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3. |
- Karlsson, Christoffer, et al.
(author)
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Stable Deep Doping of Vapor-Phase Polymerized Poly(3,4-ethylenedioxythiophene)/Ionic Liquid Supercapacitors.
- 2016
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In: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 9:16, s. 2112-2121
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Journal article (peer-reviewed)abstract
- Liquid-solution polymerization and vapor-phase polymerization (VPP) have been used to manufacture a series of chloride- and tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT) carbon paper electrodes. The electrochemistry, specific capacitance, and specific charge were determined for single electrodes in 1-ethyl-3-methylimidazolium dicyanamide (emim dca) ionic liquid electrolyte. VPP-PEDOT exhibits outstanding properties with a specific capacitance higher than 300 F g(-1) , the highest value reported for a PEDOT-based conducting polymer, and doping levels as high as 0.7 charges per monomer were achieved. Furthermore, symmetric PEDOT supercapacitor cells with the emim dca electrolyte exhibited a high specific capacitance (76.4 F g(-1) ) and high specific energy (19.8 Wh kg(-1) ). A Ragone plot shows that the VPP-PEDOT cells combine the high specific power of conventional ("pure") capacitors with the high specific energy of batteries, a highly sought-after target for energy storage.
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4. |
- Keskinen, Jari, et al.
(author)
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Asymmetric and symmetric supercapacitors based on polypyrrole and activated carbon electrodes
- 2015
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In: Synthetic metals. - : Elsevier BV. - 0379-6779 .- 1879-3290. ; 203, s. 192-199
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Journal article (peer-reviewed)abstract
- Abstract Supercapacitors were prepared using either two polypyrrole (PPy) composite electrodes or one PPy composite and one activated carbon electrode. The PPy composite electrodes were either freestanding paper-like sheets or PPy films printed on graphite ink coated aluminium/PET laminate substrates, using Cladophora algae derived cellulose as the substrate or binder, respectively. The specific capacitance of the PPy electrodes was found to be about 200 F g−1 depending on the manufacturing method, yielding supercapacitors with capacitances between 0.45 and 3.8 F and energy efficiencies of over 90%. For an asymmetric device with activated carbon positive electrode and PPy negative electrode a capacitance loss of 5% was seen after 14300 cycles.
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7. |
- Malehmir, Alireza, 1977-, et al.
(author)
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Smart Exploration Research Centre : Knowledge and Innovation for Exploration of Critical Raw Materials
- 2024
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In: First Break. - : European Association of Geoscientists & Engineers. - 0263-5046 .- 1365-2397. ; 42:8, s. 89-93
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Journal article (peer-reviewed)abstract
- In response to the rising needs for long-term research and innovation in the field of critical raw material exploration, the Smart Exploration Research Centre was established in 2024 in Sweden. Funded by the Swedish Foundation for Strategic Research (SSF), this initiative involves collaboration among academic institutions, industry, and the public sector. Building on the H2020-funded Smart Exploration project, which involved 27 European organisations including the European Association of Geoscientists and Engineers (EAGE), the centre aims to advance the global standing of Sweden’s exploration. It seeks to gather skills and create a network that will leave a lasting legacy in the field of mineral exploration. The multidisciplinary centre aims to be a fast-track hub for addressing exploration challenges in the mining industry through synergistic efforts. It connects exploration with mineral processing and nanotechnology to enhance environmental studies and develop effective extraction and beneficiation methods.
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9. |
- Pochard, Isabelle, et al.
(author)
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Amine-functionalised mesoporous magnesium carbonate : Dielectric spectroscopy studies of interactions with water and stability
- 2018
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In: Materials Chemistry and Physics. - : ELSEVIER SCIENCE SA. - 0254-0584 .- 1879-3312. ; 216, s. 332-338
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Journal article (peer-reviewed)abstract
- A mesoporous magnesium carbonate (MMC) material that was first described in 2013 is currently being investigated for several industrial and life-science-based applications. In this paper, the effect of functionalising the surface of MMC with amine groups on the water interaction properties of the material is investigated in detail. Amine functionalisation enhanced the stability and water sorption-release properties of the material. This is explained by the low affinity between amine-functionalised MMC and water molecules, as attested by the high free/total water ratio shown by dielectric spectroscopy. This low affinity had an impact on the total amount of adsorbed water at low relative humidities (RHs) but not at high RHs. The functionalisation of MMC with amine groups also stabilised the material in moist environments, hindering spontaneous crystallisation. These results provide a more fundamental understanding of the water interaction properties of MMC and are also expected to facilitate optimisation of the stability of materials like this for novel drug formulations and other life-science applications, as well as for their use in humidity control.
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10. |
- Rostedt Punga, Anna, et al.
(author)
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Flodvåg av långtidssjuka covid-19-patienter väntar
- 2020
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In: Dagens Nyheter. - : Dagens Nyheter. - 1101-2447. ; , s. 5-5
-
Journal article (pop. science, debate, etc.)abstract
- Hittills har sjukvård och forskning fokuserat på de som är svårt sjuka i covid-19. Samhällsspridningen i Sverige gör att även primärvården måste förbereda sig på ett stort antal patienter med komplexa och långdragna symtom. Nu publiceras en av de första vetenskapliga fallbeskrivningarna av en långtidssjuk patient, skriver forskare vid Uppsala universitet.
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11. |
- Sörensen, Jan H, et al.
(author)
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Co-precipitation of Tobramycin into Biomimetically Coated Orthopedic Fixation Pins Employing Submicron-Thin Seed Layers of Hydroxyapatite
- 2014
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In: Current Drug Delivery. - : Bentham Science Publishers Ltd.. - 1567-2018 .- 1875-5704. ; 11:4, s. 501-510
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Journal article (peer-reviewed)abstract
- Implant migration, loosening and cut-out as well as nosocomial infections are current problems during surgery. New innovative strategies to overcome these issues are emphasized in today's research. The currentwork presents a novel strategy involving co-precipitation ofTobramycin with biomimetic hydroxyapatite (HA) formation to produce implant coatings that may ensure controlled local drug delivery to prevent early bacterial colonization of the implant. A sub-micron thin HA layer served as seed layer for the co-precipitation process and allowed for incorporation of Tobramycin in the coating from a stock solution of antibiotic concentrations as high as 20 mg/ml. Concentrations from 0.5 to 20 mg/ml Tobramycin and process temperatures of 37 °C and 60 °C were tested to assess the optimal parameters resulting in a thin Tobramycin delivering HA coating on discs and orthopedic fixation pins. The coating morphology and thickness as well as drugrelease profile were evaluated via scanning electron microscopy and high performanceliquid chromatography. The coatings were found to deliver pharmaceutically relevant amounts of Tobramycinover a period as of12 days. To the best of our knowledge, this is the longest release period ever observed for a fast-loaded biomimetic implant coating. The presented approach may form thefoundation for development of combination device/antibiotic delivery vehicles tailored to meet well-defined clinical needs combatting infections and ensuring fast implant in-growth.
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12. |
- Tammela, Petter, et al.
(author)
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Asymmetric supercapacitors based on carbon nanofibre and polypyrrole/nanocellulose composite electrodes
- 2015
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In: RSC Advances. - 2046-2069. ; 5:21, s. 16405-16413
-
Journal article (peer-reviewed)abstract
- Asymmetric, all-organic supercapacitors (containing an aqueous electrolyte), exhibiting a capacitance of 25 F g-1 (or 2.3 F cm-2) at a current density of 20 mA cm-2 and a maximum cell voltage of 1.6 V, are presented. The devices contain a composite consisting of polypyrrole covered Cladophora cellulose fibres (PPy-cellulose) as the positive electrode while a carbon nanofibre material, obtained by heat treatment of the same PPy-cellulose composite under nitrogen gas flow, serves as the negative electrode. Scanning and transmission electron microscopy combined with X-ray photoelectron spectroscopy data show that the heat treatment gives rise to a porous carbon nanofibre material, topologically almost identical to the original PPy-cellulose composite. The specific gravimetric capacitances of the carbon and the PPy-cellulose electrodes were found to be 59 and 146 F g-1, respectively, while the asymmetric supercapacitors exhibited a gravimetric energy density of 33 J g-1. The latter value is about two times higher than the energy densities obtainable for a symmetric PPy-cellulose device as a result of the larger cell voltage range accessible. The capacitance obtained for the asymmetric devices at a current density of 156 mA cm-2 was 11 F g-1 and cycling stability results further indicate that the capacity loss was about 23% during 1000 cycles employing a current density of 20 mA cm-2. The present results represent a significant step forward towards the realization of all-organic material based supercapacitors with aqueous electrolytes and commercially viable capacitances and energy densities.
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13. |
- Tikhomirov, Evgenii
(author)
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Selective laser sintering for 3D printing of medications
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Suboptimal treatment caused by inaccurate dosing of prescribed medications is a challenging issue for the pharmaceutical industry. As a result, certain groups of patients, especially pediatric patients, may suffer from a lack of specific dosage forms, leading to potential side effects. To address this issue, various manipulation techniques are being applied, such as tablet crushing, splitting, and solution preparations. Unfortunately, these methods lack accuracy and economic efficiency.3D printing technology has been considered one of the potential solutions for manufacturing limited batch dosage forms. Dosage forms produced through 3D printing can be fabricated on demand for specific patients. Furthermore, the unique properties of these dosage forms, such as API amorphization, can be adjusted due to the high tunability of the 3D printing process. The work conducted in this thesis is dedicated to investigating the potential applications of Selective Laser Sintering (SLS) and the associated aspects of this method for manufacturing solid dosage forms.The investigations into printing parameters and formulation content enabled the establishment of correlations between these factors and the properties of the final dosage forms. Higher print temperature, Laser Power Ratio, and colorant concentration led to increased mass and hardness of the dosage forms.The polymer constitutes the major portion of the formulation in terms of mass. Consequently, various grades of polymer were examined to ascertain their chemical influence on the properties of the dosage forms. The findings revealed that the type of polymer, degree of hydrolysis, and dynamic viscosity of the polymer significantly impact both the dissolution rate and API amorphization.Utilizing FDM for printing the shell component of the drug delivery device improved its durability, whereas the SLS-printed insert resulted in a faster and adjustable dissolution rate. This experiment showcased the potential of combining the advantages of each technique to produce dosage forms with additional features.A thermal image analysis device was developed and employed to monitor temperature conditions throughout the printing process. The outcomes demonstrated that the collected data could be utilized for in-process quality control objectives and serve as a dataset for machine learning algorithms. This capability allows for real-time process monitoring, defect detection, and automated process refinement.In conclusion, a comprehensive study was conducted on the application of SLS and its limitations. This study will hopefully pave the way for further discussions and the implementation of this technology.
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14. |
- Vall, Maria, et al.
(author)
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Amine-Modified Mesoporous Magnesium Carbonate as an Effective Adsorbent for Azo Dyes
- 2019
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In: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 4:2, s. 2973-2979
-
Journal article (peer-reviewed)abstract
- Mesoporous magnesium carbonate (MMC) was evaluated as a potential candidate material for removal of dyes from textile industry wastewater. The adsorption property of MMC was analyzed for three different azo dyes: reactive black 5 (RB5), amaranth (AM), and acid red 183 (AR183). Further, the effect of porosity, amine modification, ionic strength, and pH was evaluated. MMC modified with 3-(aminopropyl)triethoxysilane (aMMC) showed consistently high uptake levels for all of the azo dyes tested; the uptake of RB5, AM, and AR183 was ∼360, ∼143 and ∼170 mg/g, respectively. The results demonstrated the importance of porosity and surface chemistry in the effective adsorption of the azo dye in aqueous systems. The uptake of RB5 and AM on aMMC was not significantly affected by pH (when varied between 4 and 10), although reduced uptake of RB5 and AM was observed at pH values <2 and >12. The addition of NaCl salt at concentrations up to 1000 mM had minimal effect on the high uptake of RB5 on aMMC. The uptake of AM by aMMC was reduced by approximately 20% in the presence of NaCl even at low concentrations. The uptake of AR183 by aMMC varied noticeably by changes in pH and no specific trend was observed. The presence of NaCl also adversely affected the uptake of AR183 on aMMC. The adsorption of the azo dye on aMMC was most likely driven by electrostatic interactions. We show here that aMMC is a potential candidate adsorbent for the effective removal of azo dyes from textile wastewaters.
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15. |
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16. |
- Vall, Maria, et al.
(author)
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Carbon dioxide adsorption on mesoporous magnesium carbonate
- 2019
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In: Energy Procedia. - : Elsevier. - 1876-6102. ; 158, s. 4671-4676
-
Journal article (peer-reviewed)abstract
- Mesoporous magnesium carbonate (MMC) was synthesized and tested for its ability to separate CO2 from N2. The pure gas CO2 uptake of MMC was around 1.5 mmol/g at 101 kPa, 0 °C. The N2 uptake under the same conditions was less than 0.1 mmol/g. Al(NO3)3, Al2O3, K2CO3 and KNO3 were introduced into the porous structure of MMC as additives. All of the additives tested increased the CO2 uptake of MMC and increased its selectivity towards CO2. The incorporation of 5 wt.% K2CO3 increased the CO2 uptake of MMC up to over 3.2 mmol/g. The ideally adsorbed solution theory was used to calculate the CO2 selectivity of MMC and MMC with additives for a hypothetical gas mixture that contained 15% CO2: 85% N2. The CO2 selectivity at 101 kPa (0 °C) was around 60. MMC with 5 wt.% K2CO3 had a CO2 selectivity of over 150 under the same conditions. Vacuum swing cyclic CO2 adsorption/desorption showed that the CO2 uptake on MMC with 5 wt.% K2CO3 decreased after each cycle. Heat regeneration (up to 250 °C, for 10 minutes) could recover most of the lost CO2 capacity after each cycle. Heat regeneration indicatively improved the cyclic performance of this adsorbent. MMC with 5 wt.% K2CO3 was the best performing adsorbent in this study and can potentially be further developed into a good CO2 adsorbent for temperature swing adsorption (TSA) processes.
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17. |
- Vall, Maria, et al.
(author)
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Effects of amine modification of mesoporous magnesium carbonate on controlled drug release
- 2017
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In: International Journal of Pharmaceutics. - : Elsevier BV. - 0378-5173 .- 1873-3476. ; 524, s. 141-147
-
Journal article (peer-reviewed)abstract
- (3-Aminopropyl)triethoxysilane (APTES) was used to modify the surface of mesoporous magnesium carbonate (MMC). The as-synthesized MMC had an average pore diameter of ∼5 nm, but amine grafting occurred preferentially on the walls of the largest MMC pores. Analysis of ibuprofen (IBU) loading and release showed that IBU remained stable in the amorphous phase in all the MMC and modified MMC samples. The kinetics of IBU release from the modified MMC were assessed and used to evaluate the effects of the different functional groups. The release rate showed that the release of IBU could be controlled by adjusting the amine surface coverage of MMC and also by changing the surface groups. It was concluded that the interaction between the grafted, functional groups in the modified MMC and the OH in the carboxyl groups of IBU was the most important factor for prolonging the release of the drug. These results are expected to lead to investigation of other as yet unexplored applications for MMC, including using it as a plastic additive and for gas separation.
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18. |
- Vall, Maria, et al.
(author)
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Exploring the use of amine modified mesoporous magnesium carbonate for the delivery of salicylic acid in topical formulations: : in vitro cytotoxicity and drug release studies
- 2019
-
In: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 24:9
-
Journal article (peer-reviewed)abstract
- Salicylic acid (SA) has for a long time been used to treat various skin disorders due to its anti-inflammatory, bacteriostatic, and antifungal properties. In the present work, mesoporous magnesium carbonate (MMC), a promising drug carrier, was modified with 3-aminopropyl-triethoxysilane to enable loading of SA. The amine modified MMC (aMMC) was successfully loaded with 8 wt.% of SA via a solvent evaporation method. SA was later completely released from the carrier in less than 15 min. Furthermore, the cytotoxicity of the functionalized material was evaluated. aMMC was found to be non-toxic for human dermal fibroblast cells with particle concentration of up to 1000 µg/mL when exposed for 48 h. The presented results form the basis of future development of aMMC as a potential carrier for SA in dermatological applications.
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19. |
- Vall, Maria, et al.
(author)
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Inorganic carbonate composites as potential high temperature CO2 sorbents with enhanced cycle stability
- 2019
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In: RSC Advances. - 2046-2069. ; 9:35, s. 20273-20280
-
Journal article (peer-reviewed)abstract
- A calcium magnesium carbonate composite (CMC) material containing highly porous amorphous calcium carbonate (HPACC) and mesoporous magnesium carbonate (MMC) was synthesized. CMCs with varying HPACC : MMC mol ratios and high BET surface area (over 490 m2 g−1) were produced. The CMCs retained the morphology shared by HPACC and MMC. All these materials were built up of aggregated nanometer-sized particles. We tested the CO2 uptake properties of the synthesized materials. The CMCs were calcined at 850 °C to obtain the corresponding calcium magnesium oxide composites (CMOs) that contained CaO : MgO at different mol ratios. CMO with CaO : MgO = 3 : 1 (CMO-3) showed comparable CO2 uptake at 650 °C (0.586 g g−1) to CaO sorbents obtained from pure HPACC (0.658 g g−1) and the commercial CaCO3 (0.562 g g−1). Over 23 adsorption–desorption cycles CMOs also showed a lower CO2 uptake capacity loss (35.7%) than CaO from HPACC (51.3%) and commercial CaCO3 (79.7%). Al was introduced to CMO by the addition of Al(NO3)3 in the synthesis of CMC-3 to give ACMO after calcination. The presence of ∼19 mol% of Al(NO3)3 in ACMO-4 significantly enhanced its stability over 23 cycles (capacity loss of 5.2%) when compared with CMO-3 (calcined CMC-3) without adversely affecting the CO2 uptake. After 100 cycles, ACMO-4 still had a CO2 uptake of 0.219 g g−1. Scanning electron microscope images clearly showed that the presence of Mg and Al in CMO hindered the sintering of CaCO3 at high temperatures and therefore, enhanced the cycle stability of the CMO sorbents. We tested the CO2 uptake properties of CMO and ACMO only under ideal laboratory testing environment, but our results indicated that these materials can be further optimized as good CO2 sorbents for various applications.
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23. |
- Afewerki, Samson, et al.
(author)
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Combined Catalysis for Engineering Bioinspired, Lignin-Based, Long-Lasting, Adhesive, Self-Mending, Antimicrobial Hydrogels
- 2020
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In: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 14:12, s. 17004-17017
-
Journal article (peer-reviewed)abstract
- The engineering of multifunctional biomaterials using a facile sustainable methodology that follows the principles of green chemistry is still largely unexplored but would be very beneficial to the world. Here, the employment of catalytic reactions in combination with biomass-derived starting materials in the design of biomaterials would promote the development of eco-friendly technologies and sustainable materials. Herein, we disclose the combination of two catalytic cycles (combined catalysis) comprising oxidative decarboxylation and quinone-catechol redox catalysis for engineering lignin-based multifunctional antimicrobial hydrogels. The bioinspired design mimics the catechol chemistry employed by marine mussels in nature. The resultant multifunctional sustainable hydrogels (1) are robust and elastic, (2) have strong antimicrobial activity, (3) are adhesive to skin tissue and various other surfaces, and (4) are able to self-mend. A systematic characterization was carried out to fully elucidate and understand the facile and efficient catalytic strategy and the subsequent multifunctional materials. Electron paramagnetic resonance analysis confirmed the long-lasting quinone-catechol redox environment within the hydrogel system. Initial in vitro biocompatibility studies demonstrated the low toxicity of the hydrogels. This proof-of-concept strategy could be developed into an important technological platform for the eco-friendly, bioinspired design of other multifunctional hydrogels and their use in various biomedical and flexible electronic applications.
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24. |
- Afewerki, Samson, 1985-, et al.
(author)
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In vitro high-content tissue models to address precision medicine challenges
- 2023
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In: Molecular Aspects of Medicine. - : Elsevier. - 0098-2997 .- 1872-9452. ; 91
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Journal article (peer-reviewed)abstract
- The field of precision medicine allows for tailor-made treatments specific to a patient and thereby improve the efficiency and accuracy of disease prevention, diagnosis, and treatment and at the same time would reduce the cost, redundant treatment, and side effects of current treatments. Here, the combination of organ-on-a-chip and bioprinting into engineering high-content in vitro tissue models is envisioned to address some precision medicine challenges. This strategy could be employed to tackle the current coronavirus disease 2019 (COVID-19), which has made a significant impact and paradigm shift in our society. Nevertheless, despite that vaccines against COVID-19 have been successfully developed and vaccination programs are already being deployed worldwide, it will likely require some time before it is available to everyone. Furthermore, there are still some uncertainties and lack of a full understanding of the virus as demonstrated in the high number new mutations arising worldwide and reinfections of already vaccinated individuals. To this end, efficient diagnostic tools and treatments are still urgently needed. In this context, the convergence of bioprinting and organ-on-a-chip technologies, either used alone or in combination, could possibly function as a prominent tool in addressing the current pandemic. This could enable facile advances of important tools, diagnostics, and better physiologically representative in vitro models specific to individuals allowing for faster and more accurate screening of therapeutics evaluating their efficacy and toxicity. This review will cover such technological advances and highlight what is needed for the field to mature for tackling the various needs for current and future pandemics as well as their relevancy towards precision medicine.
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25. |
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26. |
- Ahrentorp, Fredrik, et al.
(author)
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Sensitive magnetic biodetection using magnetic multi-core nanoparticles and RCA coils
- 2017
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In: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 427, s. 14-18
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Journal article (peer-reviewed)abstract
- We use functionalized iron oxide magnetic multi-core particles of 100 nm in size (hydrodynamic particle diameter) and AC susceptometry (ACS) methods to measure the binding reactions between the magnetic nanoparticles (MNPs) and bio-analyte products produced from DNA segments using the rolling circle amplification (RCA) method. We use sensitive induction detection techniques in order to measure the ACS response. The DNA is amplified via RCA to generate RCA coils with a specific size that is dependent on the amplification time. After about 75 min of amplification we obtain an average RCA coil diameter of about 1 mu m. We determine a theoretical limit of detection (LOD) in the range of 11 attomole (corresponding to an analyte concentration of 55 fM for a sample volume of 200 mu L) from the ACS dynamic response after the MNPs have bound to the RCA coils and the measured ACS readout noise. We also discuss further possible improvements of the LOD.
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27. |
- Alvebratt, Caroline, et al.
(author)
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A Modified In Situ Method to Determine Release from a Complex Drug Carrier in Particle-Rich Suspensions
- 2018
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In: AAPS PharmSciTech. - : Springer Science and Business Media LLC. - 1530-9932. ; 19:7, s. 2859-2865
-
Journal article (peer-reviewed)abstract
- Effective and compound-sparing methods to evaluate promising drug delivery systems are a prerequisite for successful selection of formulations in early development stages. The aim of the study was to develop a small-scale in situ method to determine drug release and supersaturation in highly concentrated suspensions of enabling formulations. Mesoporous magnesium carbonate (MMC), which delivers the drug in an amorphous form, was selected as a drug carrier. Five model compounds were loaded into the MMC at a 1:10 ratio using a solvent evaporation technique. The μDiss Profiler was used to study the drug release from MMC in fasted-state simulated intestinal fluid. To avoid extensive light scattering previously seen in particle-rich suspensions in the μDiss Profiler, an in-house-designed protective nylon filter was placed on the in situ UV probes. Three types of release experiments were conducted for each compound: micronized crystalline drug with MMC present, drug-loaded MMC, and drug-loaded MMC with 0.01% w/w hydroxypropyl methyl cellulose. The nylon filters effectively diminished interference with the UV absorption; however, the release profiles obtained were heavily compound dependent. For one of the compounds, changes in the UV spectra were detected during the release from the MMC, and these were consistent with degradation of the compound. To conclude, the addition of protective nylon filters to the probes of the μDiss Profiler is a useful contribution to the method, making evaluations of particle-rich suspensions feasible. The method is a valuable addition to the current ones, allowing for fast and effective evaluation of advanced drug delivery systems.
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28. |
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29. |
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31. |
- Alvebratt, Caroline
(author)
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Advanced Methods for Evaluation of the Performance of Complex Drug Delivery System
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Low oral bioavailability of drugs originating from poor aqueous solubility is a common issue in drug development. Various enabling formulations have been presented to circumvent this limitation, many making use of supersaturation. In these, the drug is delivered to the gastro-intestinal lumen in a high energy state e.g. in amorphous form or a liquid lipid vehicle. Concentrations surpassing the equilibrium solubility of the crystalline drug are achieved, which facilitate increased absorption for dissolution-rate limited compounds. Meanwhile the use of the enabling formulation can be beneficial to increase the bioavailability of poorly water-soluble drugs, in vitro evaluation of these systems remain challenging. Limited methods have also evaluated several different types of enabling formulation in the same experimental setup. The overall aim of this thesis was therefore to develop assays to study the performance of various complex drug delivery systems. In the first part, a small scale dissolution apparatus, the µDiss Profiler, was used to study drug release from drug-loaded mesoporous magnesium carbonate (MMC). A protective filter was developed to minimize particle interference on the UV-measurements, enabling studies of supersaturation from the amorphous carrier. In the second paper, lipids were adsorbed onto the MMC. A modified in vitro lipolysis setup was established and the samples were analyzed with nuclear magnetic resonance spectroscopy. A stability study of the lipid-loaded MMC was also performed. The methods developed in the first two projects provided an insight to events occurring in the intestinal lumen. The intestinal absorption has however been shown to be a complex interplay between dissolution-digestion and permeation. In the final two projects, two devices comprising of a donor (luminal) chamber and a receiver (serosal) chamber were studied (the µFLUX and the enabling absorption, ENA, device). The two chambers were separated by a semipermeable membrane (cell-based and/or phospholipid-based). A wide range of enabling formulations were evaluated in the two assays. As the exposure in the donor correlated poorly with the exposure in the receiver compartment, this emphasizes the importance of in vitro methods taking both the dissolution-digestion and permeation into account. The ENA results also predicted the in vivo performance in rats well. To conclude, several models have been established in the thesis to study the in vitro performance of enabling formulations, which will be valuable for screening of appropriate drug delivery systems.
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32. |
- Alvebratt, Caroline, et al.
(author)
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An in vitro dissolution–digestion–permeation assay for the study of advanced drug delivery systems
- 2020
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In: European journal of pharmaceutics and biopharmaceutics. - : Elsevier BV. - 0939-6411 .- 1873-3441. ; 149, s. 21-29
-
Journal article (peer-reviewed)abstract
- Advanced drug delivery systems (ADDS) are widely explored to overcome poor aqueous solubility of orally administered drugs. However, the prediction of their in vivo performance is challenging, as in vitro models typically do not capture the interplay between processes occurring in the gut. In additions, different models are used to evaluate the different systems. We therefore present a method that allows monitoring of luminal processing (dissolution, digestion) and its interplay with permeation to better inform on the absorption of felodipine formulated as ADDS. Experiments were performed in a µFLUX-apparatus, consisting of two chambers, representing the intestinal and serosal compartment, separated by Caco-2 monolayers. During dissolution–digestion–permeation experiments, ADDS were added to the donor compartment containing simulated intestinal fluid and immobilized lipase. Dissolution and permeation in both compartments were monitored using in situ UV-probes or, when turbidity interfered the measurements, with HPLC analysis.The method showed that all ADDS increased donor and receiver concentrations compared to the condition using crystalline felodipine. A poor correlation between the compartments indicated the need for an serosal compartment to evaluate drug absorption from ADDS. The method enables medium-throughput assessment of: (i) dynamic processes occurring in the small intestine, and (ii) drug concentrations in real-time.
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33. |
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34. |
- Alvebratt, Caroline, et al.
(author)
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In Vitro Performance and Chemical Stability of Lipid-Based Formulations Encapsulated in a Mesoporous Magnesium Carbonate Carrier
- 2020
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In: Pharmaceutics. - : MDPI AG. - 1999-4923. ; 12:5
-
Journal article (peer-reviewed)abstract
- Lipid-based formulations can circumvent the low aqueous solubility of problematic drug compounds and increase their oral absorption. As these formulations are often physically unstable and costly to manufacture, solidification has been suggested as a way to minimize these issues. This study evaluated the physicochemical stability and in vitro performance of lipid-loaded mesoporous magnesium carbonate (MMC) particles with an average pore size of 20 nm. A medium chain lipid was loaded onto the MMC carrier via physical adsorption. A modified in vitro lipolysis setup was then used to study lipid release and digestion with 1H nuclear magnetic resonance spectroscopy. The lipid loading efficiency with different solidification techniques was also evaluated. The MMC, unlike more commonly used porous silicate carriers, dissolved during the lipolysis assay, providing a rapid release of encapsulated lipids into solution. The digestion of the dispersed lipid-loaded MMC therefore resembled that of a coarse dispersion of the lipid. The stability data demonstrated minor degradation of the lipid within the pores of the MMC particles, but storage for three months did not reveal extensive degradation. To conclude, lipids can be adsorbed onto MMC, creating a solid powder from which the lipid is readily released into the solution during in vitro digestion. The chemical stability of the formulation does however merit further attention.
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35. |
- Araujo, Rafael B., et al.
(author)
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Assessing Electrochemical Properties of Polypyridine and Polythiophene for Prospective Application in Sustainable Organic Batteries
- 2017
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In: Physical Chemistry, Chemical Physics - PCCP. - 1463-9076 .- 1463-9084. ; 19:4, s. 3307-3314
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Journal article (peer-reviewed)abstract
- Conducting polymers are being considered promising candidates for sustainable organic batteries mainly due to their fast electron transport properties and high recyclability. In this work, key properties of polythiophene and polypyridine have been assessed through a combined theoretical and experimental study focusing on such applications. A theoretical protocol has been developed to calculate redox potentials in solution within the framework of the density functional theory and using continuous solvation models. Here, the evolution of the electrochemical properties of solvated oligomers as a function of the length of the chain is analyzed and then the polymer properties are estimated via linear regressions using ordinary least square. The predicted values were verified against our electrochemical experiments. This protocol can now be employed to screen a large database of compounds in order to identify organic electrodes with superior properties.
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36. |
- Araujo, Rafael B., et al.
(author)
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Designing strategies to tune reduction potential of organic molecules for sustainable high capacity batteries application
- 2017
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In: Journal of Materials Chemistry A. - 2050-7488 .- 2050-7496. ; 5:9, s. 4430-4454
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Journal article (peer-reviewed)abstract
- Organic compounds evolve as a promising alternative to the currently used inorganic materials in rechargeable batteries due to their low-cost, environmentally friendliness and flexibility. One of the strategies to reach acceptable energy densities and to deal with the high solubility of known organic compounds is to combine small redox active molecules, acting as capacity carrying centres, with conducting polymers. Following this strategy, it is important to achieve redox matching between the chosen molecule and the polymer backbone. Here, a synergetic approach combining theory and experiment has been employed to investigate this strategy. The framework of density functional theory connected with the reaction field method has been applied to predict the formal potential of 137 molecules and identify promising candidates for the referent application. The effects of including different ring types, e.g. fused rings or bonded rings, heteroatoms, [small pi] bonds, as well as carboxyl groups on the formal potential, has been rationalized. Finally, we have identified a number of molecules with acceptable theoretical capacities that show redox matching with thiophene-based conducting polymers which, hence, are suggested as pendent groups for the development of conducting redox polymer based electrode materials.
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37. |
- Basu, Alex, et al.
(author)
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In Vitro and in Vivo Evaluation of the Wound Healing Properties of Nanofibrillated Cellulose Hydrogels
- 2018
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In: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 1:6, s. 1853-1863
-
Journal article (peer-reviewed)abstract
- Current trends in wound care research move toward the development of wound healing dressings designed to treat different types of wounds (e.g., burns and chronic wounds) and toward tailoring treatments for different stages of the wound healing process. In this context, the development of advanced nanotherapeutic materials is highlighted as a promising strategy to efficiently control specific phases of the wound healing process. Here, Ca2+-cross-linked wood-derived nanofibrillated cellulose (NFC) hydrogels are evaluated as wound healing dressings. In vitro biocompatibility assays were performed to study the interaction of the NFC hydrogels with cellular processes that are tightly related to wound healing. Moreover, an in vivo dermo-epidermic full thickness wound healing model in rat was used to uncover the wound healing ability of the Ca2+-cross-linked NFC hydrogels. The in vitro experiments showed that the NFC hydrogels were able to support fibroblast and keratinocyte proliferation. A potential effect of the hydrogels on triggering keratinocyte differentiation was furthermore proposed. In vivo, the NFC hydrogels stimulated healing without causing any adverse local tissue effects, potentially owing to their moisture-donating properties and the herein discussed aiding effect of the Ca2+-cross-linker on epidermal generation. Thus, this work extensively demonstrates the wound healing ability of NFC hydrogels and presents an important milestone in the research on NFC toward advanced wound healing applications.
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38. |
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39. |
- Basu, Alex, et al.
(author)
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Ion-crosslinked wood-derived nanocellulose hydrogels with tunable antibacterial properties : Candidate materials for advanced wound care applications
- 2018
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In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 181, s. 345-350
-
Journal article (peer-reviewed)abstract
- Development of advanced dressings with antimicrobial properties for the treatment of infected wounds is an important approach in the fight against evolution of antibiotic resistant bacterial strains. Herein, the effects of ion-crosslinked nanocellulose hydrogels on bacteria commonly found in infected wounds were investigated in vitro. By using divalent calcium or copper ions as crosslinking agents, different antibacterial properties against the bacterial strains Staphylococcus epidermidis and Pseudomonas aeruginosa were obtained. Calcium crosslinked hydrogels were found to retard S. epidermidis growth (up to 266% increase in lag time, 36% increase in doubling time) and inhibited P. aeruginosa biofilm formation, while copper crosslinked hydrogels prevented S. epidermidis growth and were bacteriostatic towards P. aeruginosa (49% increase in lag time, 78% increase in doubling time). The wound dressing candidates furthermore displayed barrier properties towards both S. epidermidis and P. aeruginosa, hence making them interesting for further development of advanced wound dressings with tunable antibacterial properties.
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40. |
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41. |
- Basu, Alex, et al.
(author)
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On the use of ion-crosslinked nanocellulose hydrogels for wound healing solutions : Physicochemical properties and application-oriented biocompatibility studies
- 2017
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In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 174, s. 299-308
-
Journal article (peer-reviewed)abstract
- Calcium ion-crosslinked nanofibrillated cellulose (NFC) hydrogels were investigated as potential materials for wound healing dressings. The physicochemical properties of the hydrogels were examined by rheology and water retention tests. Skin cells and monocytes were selected for application-oriented bio-compatibility studies. The NFC hydrogels presented entangled fibrous networks and solid-like behavior. Water retention tests showed the material's potential to maintain a suitable moist environment for different type of wounds. The hydrogels did not affect dermal fibroblasts monolayer cultures upon directcontact, as cell monolayers remained intact after application, incubation and removal of the materials. Inflammatory response studies with blood-derived mononuclear cells revealed the inert nature of the hydrogels in terms of cytokine secretion and reactive oxygen species production. Results highlight the great potential of ion-crosslinked NFC hydrogels for the development of advanced wound dressings, where further functionalization of the material could lead to improved properties towards the healing of specific wound types.
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42. |
- Basu, Alex, et al.
(author)
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Towards Tunable Protein-Carrier Wound Dressings Based on Nanocellulose Hydrogels Crosslinked with Calcium Ions
- 2018
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In: Nanomaterials. - : MDPI. - 2079-4991. ; 8:7
-
Journal article (peer-reviewed)abstract
- A Ca2+-crosslinked wood-based nanofibrillated cellulose (NFC) hydrogel was investigated to build knowledge toward the use of nanocellulose for topical drug delivery applications in a chronic wound healing context. Proteins of varying size and isoelectric point were loaded into the hydrogel in a simple soaking procedure. The release of the proteins from the hydrogel was monitored and kinetics determining parameters of the release processes were assessed. The integrity of the hydrogel and proteins were also studied. The results showed that electrostatic interactions between the proteins and the negatively-charged NFC hydrogel structure played a central role in the loading process. The release of the proteins were governed by Fickian diffusion. An increased protein size, as well as a positive protein charge facilitated a slower and more sustained release process from the hydrogel matrix. At the same time, the positively-charged protein was shown to increase the post-loading hydrogel strength. Released proteins maintained structural stability and activity, thus indicating that the Ca2+-crosslinked NFC hydrogel could function as a carrier of therapeutic proteins without compromising protein function. It is foreseen that, by utilizing tunable charge properties of the NFC hydrogel, release profiles can be tailored to meet very specific treatment needs.
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43. |
- Björklund, Håkan, et al.
(author)
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Ett aktivt svenskt värdskap för ESS är viktigare än någonsin : Regeringen måste ta ett aktivt ledarskap och säkra de extra resurser som krävs för att ESS ska bli tillgängligt för forskarsamhället och näringslivet, skriver rådgivare till ESS.
- 2022
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In: Dagens Industri. - Stockholm : Dagens Industri. ; 5/4
-
Journal article (peer-reviewed)abstract
- Kriget i Ukraina visar på behovet av att det fria Europa står på egna ben och bygger sig starkt och då spelar forskning och utveckling en viktig roll. Den forskningsinfrastruktur som nu byggs i Sverige – till exempel European Spallation Source (ESS) – har stor betydelse för att vi ska behålla och utveckla vårt teknologiska ledarskap och samtidigt bidra till att lösa de stora utmaningar mänskligheten står inför. De flesta av oss vill se ett starkt och attraktivt Europa som kännetecknas av innovation, framtidstro och medmänsklighet. I en konkurrensutsatt värld behöver samhällsdebatten handla mer om hur vi skapar vårt välstånd, för det kommer inte av sig självt. Sverige har lång tradition av nyfiket uppfinnande, skickligt ingenjörskap och drivna entreprenörer. Det är så vi har skapat de svenska företag som nu är globala. Vi säljer varor och tjänster på en världsmarknad, vilket förutsätter teknologiskt ledarskap och spetskompetens. Exportnettot, handelsbalansens överskott, omvandlas till välstånd hemmavid och det går en rak linje från innovationer till äldreomsorg. Men att vara ett innovativt ledande land är en position som ständigt måste erövras. Varje dag. Efter 150 år av forskning och framsteg, tillväxt och ökande välstånd, växer mänskligheten in i en ny fas. Vi kommer att behöva leva, producera och konsumera på nya sätt. Utmaningarna är kända, men lösningarna är okända och det är bråttom. De stora frågorna har många svar och redskapen för att förflytta vår kunskaps gräns blir alltmer avancerade. Nya skräddarsydda material är väsentliga för att lösa många av utmaningarna. I industrins barndom kom ingenjörerna långt med envishet och enkla verktyg. Men de lågt hängande frukterna är plockade. De enkla lösningarna implementerade. För att kunna fortsätta krävs alltmer avancerade metoder och angreppssätt som kräver miljardinvesteringar för att studera material i dess minsta beståndsdelar och se hur celler reagerar på olika substanser. Energiutmaningen har inte en enda storskalig lösning utan behöver ständiga framsteg inom allt från processteknik till energialstring. Cancer har inte ett motmedel, utan stävjas genom många upptäckter inom allt från immunologi till radiologi. De tusen stegens innovationer avgör vår förmåga att lyckas med omställningen till ett mer hållbart samhälle och att utveckla nya behandlingsformer och botemedel. Att Sverige och svensk industri tar en ledande roll i denna utveckling borde vara självklart för alla. För drygt tjugo år sedan tog nordiska forskare initiativ till att skapa en världsledande infrastruktur för materialforskning i Sverige. Nu installeras instrumenten på ESS medan forskning redan pågår hos grannen MAX IV. ESS är en av Europas största vetenskapliga satsningar och beräknas vara i drift under 40 års tid. Sverige har fått ett guldägg i sin famn – sin första globala Big Science anläggning någonsin – och är värdland med Danmark som medvärd. Tretton av Europas mest tekniskt avancerade nationer finansierar detta tillsammans. ESS beräknas bli 20 gånger mer kraftfull än befintliga motsvarande anläggningar, vilket kommer att ge forskare tillgång till världens skarpaste ”öga” in i organisk och oorganisk materia. ESS blir ett verktyg som kan hjälpa mänskligheten att söka svar på många frågor som måste lösas inom energi, medicin, bioteknik, datalagring och -processing, ja inom alla områden som behöver smarta material. Närheten till Max IV är genomtänkt och en stor möjlighet. Anläggningarna kompletterar varandra och kommer att kunna bidra till ny banbrytande kunskap, nya innovationer och nya företag. Den forskning som kommer att bedrivas vid ESS stämmer väl med vår industriella tradition av ingenjörskap och det ständiga sökandet efter bättre produkter och processer. För Sverige innebär närvaron av ESS en exceptionell möjlighet. Tusentals spetsforskare från hela världen kommer varje år att komma till Sverige. Den förstärkning det innebär för forskarsamhälle, innovationsklimat och näringsliv är stor och kommer inte att likna något vi hittills sett. Satsningen kräver aktivt svenskt värdskap.ESS stärker Sveriges rykte som kunskapsnation, förbättrar vår konkurrenskraft och ger större möjligheter att tackla samhällsutmaningarna genom samverkan mellan näringsliv, samhälle och akademi. Det är en mycket långsiktig satsning som handlar om vårt framtida välstånd. För att få utdelning på Sveriges investering måste vi se till att svenska företag blir bäst i världen på att använda ESS. I dag finns en nationell strategi och ett kansli kopplat till Vetenskapsrådet och Vinnova, men det är bara början. Därför har vi valt att engagera oss ideellt, som rådgivare till ESS, för att stödja samarbetet mellan företag, samhälle och ESS.Ett aktivt svenskt värdskap för ESS är viktigare än någonsin. Pandemin leder till förseningar och därmed kostnadsökningar av stora och komplexa projekt som ESS, men förstärker samtidigt det långsiktiga behovet av ny kunskap. Det är ytterst viktigt att vi nu bäddar för framtiden så att ESS kommer i drift så snart som möjligt och kan bidra till att lösa de stora utmaningar vi står inför. Vi uppmanar därför regeringen att ta ett aktivt ledarskap för ESS genom att tillsammans med övriga medlemsländer säkra de extra resurser som krävs för att ESS ska bli tillgängligt för forskarsamhället och näringslivet så snart som möjligt.ESS blir världens mest kraftfulla verktyg för forskare. Håkan Björklund, styrelsearbetareArne Karlsson, styrelsearbetareLena Olving, styrelsearbetareBjörn Savén, grundare IK PartnersMaria Strömme, professor i nanoteknologiArtikelförfattarna är medlemmar i ESS Executive Advisory Board, ett rådgivande organ.
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44. |
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45. |
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46. |
- Blasi-Romero, Anna, et al.
(author)
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In Vitro Investigation of Thiol-Functionalized Cellulose Nanofibrils as a Chronic Wound Environment Modulator
- 2021
-
In: Polymers. - : MDPI. - 2073-4360. ; 13:2
-
Journal article (peer-reviewed)abstract
- There is currently a huge need for new, improved therapeutic approaches for the treatment of chronic wounds. One promising strategy is to develop wound dressings capable of modulating the chronic wound environment (e.g., by controlling the high levels of reactive oxygen species (ROS) and proteases). Here, we selected the thiol-containing amino acid cysteine to endow wood-derived cellulose nanofibrils (CNF) with bioactivity toward the modulation of ROS levels and protease activity. Cysteine was covalently incorporated into CNF and the functionalized material, herein referred as cys-CNF, was characterized in terms of chemical structure, degree of substitution, radical scavenging capacity, and inhibition of protease activity. The stability of the thiol groups was evaluated over time, and an in vitro cytotoxicity study with human dermal fibroblasts was performed to evaluate the safety profile of cys-CNF. Results showed that cys-CNF was able to efficiently control the activity of the metalloprotease collagenase and to inhibit the free radical DPPH (1,1-Diphenyl-2-picrylhydrazyl radical), activities that were correlated with the presence of free thiol groups on the nanofibers. The stability study showed that the reactivity of the thiol groups challenged the bioactivity over time. Nevertheless, preparing the material as an aerogel and storing it in an inert atmosphere were shown to be valid approaches to increase the stability of the thiol groups in cys-CNF. No signs of toxicity were observed on the dermal fibroblasts when exposed to cys-CNF (concentration range 0.1-0.5 mg/mL). The present work highlights cys-CNF as a promising novel material for the development of bioactive wound dressings for the treatment of chronic wounds.
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47. |
- Blomgren, Jakob, et al.
(author)
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Development of a sensitive induction-based magnetic nanoparticle biodetection method
- 2018
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In: Nanomaterials. - : MDPI AG. - 2079-4991. ; 8:11
-
Journal article (peer-reviewed)abstract
- We developed a novel biodetection method for influenza virus based on AC magnetic susceptibility measurement techniques (the DynoMag induction technique) together with functionalized multi-core magnetic nanoparticles. The sample consisting of an incubated mixture of magnetic nanoparticles and rolling circle amplified DNA coils is injected into a tube by a peristaltic pump. The sample is moved as a plug to the two well-balanced detection coils and the dynamic magnetic moment in each position is read over a range of excitation frequencies. The time for making a complete frequency sweep over the relaxation peak is about 5 minutes (10 Hz–10 kHz with 20 data points). The obtained standard deviation of the magnetic signal at the relaxation frequency (around 100 Hz) is equal to about 10−5 (volume susceptibility SI units), which is in the same range obtained with the DynoMag system. The limit of detection with this method is found to be in the range of 1 pM.
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48. |
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