| 1. |
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| 2. |
- Bai, Yang, et al.
(författare)
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Geometry design of tethered small-molecule acceptor enables highly stable and efficient polymer solar cells
- 2023
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Ingår i: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- With the power conversion efficiency of binary polymer solar cells dramatically improved, the thermal stability of the small-molecule acceptors raised the main concerns on the device operating stability. Here, to address this issue, thiophene-dicarboxylate spacer tethered small-molecule acceptors are designed, and their molecular geometries are further regulated via the thiophene-core isomerism engineering, affording dimeric TDY-alpha with a 2, 5-substitution and TDY-beta with 3, 4-substitution on the core. It shows that TDY-alpha processes a higher glass transition temperature, better crystallinity relative to its individual small-molecule acceptor segment and isomeric counterpart of TDY-beta, and amore stablemorphology with the polymer donor. As a result, the TDY-alpha based device delivers a higher device efficiency of 18.1%, and most important, achieves an extrapolated lifetime of about 35000 hours that retaining 80% of their initial efficiency. Our result suggests that with proper geometry design, the tethered small-molecule acceptors can achieve both high device efficiency and operating stability.
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| 3. |
- Hua, Geng, et al.
(författare)
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Anionic polycondensation and equilibrium driven monomer formation of cyclic aliphatic carbonates
- 2018
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Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 8:68, s. 39022-39028
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Tidskriftsartikel (refereegranskat)abstract
- The current work explores the sodium hydride mediated polycondensation of aliphatic diols with diethyl carbonate to produce both aliphatic polycarbonates and cyclic carbonate monomers. The lengths of the diol dictate the outcome of the reaction; for ethylene glycol and seven other 1,3-diols with a wide array of substitution patterns, the corresponding 5-membered and 6-membered cyclic carbonates were synthesized in excellent yield (70-90%) on a 100 gram scale. Diols with longer alkyl chains, under the same conditions, yielded polycarbonates with an M-w ranging from 5000 to 16000. In all cases, the macromolecular architecture revealed that the formed polymer consisted purely of carbonate linkages, without decarboxylation as a side reaction. The synthetic design is completely solvent-free without any additional post purification steps and without the necessity of reactive ring-closing reagents. The results presented within provide a green and scalable approach to synthesize both cyclic carbonate monomers and polycarbonates with possible applications within the entire field of polymer technology.
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| 4. |
- Hua, Geng, et al.
(författare)
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Exploiting Ring-Opening Aminolysis–Condensation as a Polymerization Pathway to Structurally Diverse Biobased Polyamides
- 2018
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602.
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Tidskriftsartikel (refereegranskat)abstract
- A pathway to biobased polyamides (PAs) via ring-opening aminolysis–condensation (ROAC) under benign conditions with diverse structure was designed. Ethylene brassylate (EB), a plant oil-derived cyclic dilactone, was used in combination with an array of diamines of diverse chemical structure, and ring-opening of the cyclic dilactone EB was revealed as a driving force for the reaction. The ROAC reactions were adjusted, and reaction conditions of 100 °C under atmospheric pressure using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as a catalyst for 24 h were optimal. The structures of the polyamides were confirmed by mass spectroscopy, FTIR, and NMR, and the PAs had viscosity average molecular weights (Mη) of ∼5–8 kDa. Glassy or semicrystalline PAs with glass transition temperatures between 48 and 55 °C, melting temperatures of 120–200 °C for the semicrystalline PAs, and thermal stabilities above 400 °C were obtained and were comparable to the existing PAs with similar structures. As a proof-of-concept of their usage, one of the PAs was shown to form fibers by electrospinning and films by melt pressing. Compared to conventional methods for PA synthesis, the ROAC route portrayed a reaction temperature at least 60–80 °C lower, could be readily carried out without a low-pressure environment, and eliminated the use of solvents and toxic chemicals. Together with the plant oil-derived monomer (EB), the ROAC route provided a sustainable alternative to design biobased PAs.
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| 5. |
- Hua, Geng, et al.
(författare)
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From Food Additive to High-Performance Heavy Metal Adsorbent : A Versatile and Well-Tuned Design
- 2016
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Ingår i: ACS Sustainable Chemistry and Engineering. - : ACS Publications. - 2168-0485.
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Tidskriftsartikel (refereegranskat)abstract
- A biosourced, cross-linked hydrogel-type heavy metal adsorbent is presented. Various factors such as the highly efficient chemical interactions, the various network structures, the decreased energy consumption during cross-linking, and the negligible amount of generated waste are considered when designing the adsorbent. The widely applied, naturally occurring food additive δ-gluconolactone is studied as a building block for the adsorbent. Aminolysis reactions were applied to form linear dimer precursors between diamines and δ-gluconolactones. The abundant hydroxyl groups on the dimers from δ-gluconolactone were fully exploited by using them as the cross-linking sites for reactions with ethylenediaminetetraacetic dianhydride, a well-known metal-chelating moiety. The versatility of the adsorbent and its metal-ion binding capacity is well tuned using dimers with different structures and by controlling the feed ratios of the precursors. Buffers with different pH values were used as the conditioning media to examine the swelling properties and the mechanical properties of the hydrogels, revealing that both properties can be controlled. High heavy metal chelating performance of the adsorbent was determined by isothermal adsorption kinetics, titration, and thermal gravimetric analysis. The adsorbent exhibits an outstanding chelating ability toward the three tested heavy metals (Cu(II), Co(II), Ni(II)), and the maximum adsorption capacity (qm ∼ 121 mg·g–1) is higher than that of the majority of the reported biosourced adsorbents.
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| 6. |
- Hua, Geng, et al.
(författare)
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Isocyanate-Free, UV-Crosslinked Poly(Hydroxyurethane) Networks: A Sustainable Approach toward Highly Functional Antibacterial Gels
- 2017
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Ingår i: Macromolecular Bioscience. - : John Wiley & Sons. - 1616-5187 .- 1616-5195.
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Tidskriftsartikel (refereegranskat)abstract
- An increased sustainabile awarness has inspired the development of new polymeric networks in a remarkable way and this strive should be combined with environmentally concerned end-uses. Therefore, a UV-crosslinked polyhydroxyurethane film with antibacterial properties is developed. First, a hydroxyurethane precursor is synthesized using aminolysis condensation, circumventing the use of isocyanates. The films are subsequently crosslinked under solvent-free conditions through a UV-triggered thiol-ene mechanism. The reactions are monitored by 1H nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy, and the networks have gel contents above 90%, and are transparent, hydrophilic, and highly flexible. Antibacterial properties are achieved by a controlled quaternization of the network's tertiary-amine and methylation of thiol-ether functionality, resulting in quaternary ammonium compounds (QACs) and sulfonium compounds. The antibacterial properties are evaluated against both Escherichia coli and Staphylococcus aureus using the agar plate diffusion and tube shaking methods. The QAC-loaded films exhibit outstanding bactericide properties (>99.9%) and the antibacterial mechanism is demonstrated to be a dual killing mechanism, i.e., diffusion killing and contact active killing.
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| 7. |
- Hua, Geng, et al.
(författare)
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One-pot inimer promoted ROCP synthesis of branched copolyesters using α-hydroxy-γ-butyrolactone as the branching reagent
- 2016
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Ingår i: Journal of Polymer Science Part A. - : John Wiley & Sons. - 0887-624X .- 1099-0518. ; 54:13, s. 1908-1918
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Tidskriftsartikel (refereegranskat)abstract
- An array of branched poly(ɛ-caprolactone)s was successfully synthesized using an one-pot inimer promoted ring-opening multibranching copolymerization (ROCP) reaction. The biorenewable, commercially available yet unexploited comonomer and initiator 2-hydroxy-γ-butyrolactone was chosen as the inimer to extend the use of 5-membered lactones to branched structures and simultaneously avoiding the typical tedious work involved in the inimer preparation. Reactions were carried out both in bulk and in solution using stannous octoate (Sn(Oct)2) as the catalyst. Polymerizations with inimer equivalents varying from 0.01 to 0.2 were conducted which resulted in polymers with a degree of branching ranging from 0.049 to 0.124. Detailed ROCP kinetics of different inimer systems were compared to illustrate the branch formation mechanism. The resulting polymer structures were confirmed by 1H, 13C, and 1H-13C HSQC NMR and SEC (RI detector and triple detectors). The thermal properties of polymers with different degree of branching were investigated by DSC, confirming the branch formation. Through this work, we have extended the current use of the non-homopolymerizable γ-butyrolactone to the branched polymers and thoroughly examined its behaviors in ROCP.
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| 8. |
- Hua, Geng, et al.
(författare)
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Phosphazene-Catalyzed Regioselective Ring-Opening Polymerization of rac-1-Methyl Trimethylene Carbonate : Colder and Less is Better
- 2019
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Ingår i: Macromolecules. - : AMER CHEMICAL SOC. - 0024-9297 .- 1520-5835. ; 52:7, s. 2681-2690
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Tidskriftsartikel (refereegranskat)abstract
- The regioselective organocatalytic ring-opening polymerization (ROP) of a 6-membered cyclic carbonate, rac-1-methyl trimethylene carbonate, was studied using phosphazene base (t-BuP2) as the principle catalyst. The influence on the reaction kinetics caused by the reaction temperature (-74-60 degrees C), catalyst loading (0.5-2.5%), and reaction solvent (toluene and tetrahydrofuran) was systematically tuned and followed by H-1 NMR. All studied reactions reached close to or above 90% monomer conversion in 3 h, and all exhibited typical equilibrium polymerization behavior that is inherent to 6-membered cyclic carbonates. Good control over the molecular weight and distribution of the polycarbonate product was obtained in most studied conditions, with M-n ranging from similar to 4k to similar to 20k and D < 1.2. The regioregularity (X-reg) of the resulting polycarbonate was thoroughly studied using various NMR techniques, with the highest X-reg obtained being.0.90. The major influence from the reaction conditions on both the ROP kinetics and X-reg are as follows: higher reaction temperature resulted in a decrease of both; higher catalyst loading resulted in a faster ROP reaction but a slight decrease in X-reg; and toluene being a better solvent resulted in both faster reaction and higher X-reg. Throughout this study, we have demonstrated the possibility to synthesize regioregular aliphatic polycarbonate using an organic base as the ROP catalyst, contrary to the existing studies on similar systems where only metal-base catalysts were in focus and our systems showed similar high X-reg of the product.
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| 9. |
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| 10. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 11. |
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| 12. |
- Lin, Lili, et al.
(författare)
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First-principles investigations on the anisotropic charge transport in 4,4 '-bis((E)-2-(naphthalen-2-yl)vinyl)-1,1 '-biphenyl single crystal
- 2014
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Ingår i: Theoretical Chemistry accounts. - : Springer Science and Business Media LLC. - 1432-881X .- 1432-2234. ; 133:9, s. 1551-
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Tidskriftsartikel (refereegranskat)abstract
- We applied the master equation method to investigate the anisotropic transport property of the 4,4'-bis((E)-2-(naphthalen-2-yl)vinyl)-1,1'-biphenyl molecular crystal based on first-principles calculation. It is found that the hole mobility has the largest value along the [100] direction, while electrons have the best transport property along the [010] direction. The anisotropic transport property was found to have close relationship with the charge transfer integral which is determined by the molecular stacking network in the crystals as well as the intermolecular frontier orbital overlap. In addition, the effect of the charge carrier density and the electronic field on the charge transport was also studied, and little effect was found except that the density is larger than 0.01 and the electronic field is increased to 1.0 x 106 V/cm. The kinetic Monte Carlo simulation method has also been used to study the anisotropic charge transport property, and consistent results were obtained as with the master equation method.
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| 13. |
- Lin, Lili, et al.
(författare)
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Theoretical insights into the charge transport in perylene diimides based n-type organic semiconductors
- 2012
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Ingår i: Organic electronics. - : Elsevier BV. - 1566-1199 .- 1878-5530. ; 13:11, s. 2763-2772
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Tidskriftsartikel (refereegranskat)abstract
- We employed a tunneling enabled hopping model to investigate the charge transport properties for four n-type organic semiconductors perylene diimides compounds. The molecular parameters are calculated by density functional theory and the transport is modeled by kinetic Monte Carlo simulation. It is found that the substitutions at the bay positions of the perylene core have large influences on the charge transport properties through modifications in molecular conformation, the charge reorganization energy as well as the stacking networks in the crystals. The temperature dependence of the mobility shows typical "band-like", in agreement with the recent experiment, but we ascribe it to be the characteristic of nuclear tunneling effect for a localized charge, not by a delocalized band. The largest charge mobility is calculated to be 16.96 cm(2)/V s for the cyano substitution, in good comparison with the experimental value of 6 cm(2)/V s.
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| 14. |
- Liu, Lei, et al.
(författare)
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Irreversible phase transitions of the multiferroic oxide Mn3TeO6 at high pressures
- 2022
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 121:4
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Tidskriftsartikel (refereegranskat)abstract
- Due to their large bandgaps, multiferroic oxides, the promising candidates for overcoming the disadvantages of metal-halide perovskites as light absorbers, have so far very limited use in solar cell applications. Previous investigations demonstrate that high pressure represents an efficient tool for tuning the bandgap of multiferroic Mn3TeO6 (MTO). However, the underlying mechanism of the giant bandgap reduction discovered in MTO remains unclear, which critically prevents the design of next-generation light absorbers. In this study, we performed in situ x-ray diffraction analyses on the structure evolution of MTO upon compression and decompression, discovering a sequence of irreversible phase transitions R(3)over bar -> C2/c -> P2(1)/n. The experimental results, supported by electronic structure calculations, show the shortening of Mn-O-Mn bonding, and, to a lower extent, the decrease in connectivity of octahedra across the phase transition, explain the giant bandgap reduction of MTO. These findings will facilitate the design and synthesis of next-generation light absorbers in solar cells.
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| 15. |
- Liu, Tang hong, et al.
(författare)
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Field test measurement of the dynamic tightness performance of high-speed trains and study on its influencing factors
- 2019
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Ingår i: Measurement: Journal of the International Measurement Confederation. - : Elsevier BV. - 0263-2241. ; 138, s. 602-613
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Tidskriftsartikel (refereegranskat)abstract
- During the actual operation of a high-speed train, the airtight performance of the carriages will change significantly. Based on a series of field tests, the external and interior pressure variations of train carriages are measured and then the dynamic pressure tightness coefficient are analysed quantitatively for investigating the airtight performance of a train passing at various speeds through tunnels of different lengths. It is found that the amplitude of the external pressure variations is proportional to the square of the train speed, while the amplitude inside the vehicle is approximately proportional to the speed to the 0.7th power due to the airtight effect. The dynamic pressure tightness coefficient increases with increasing tunnel length and decreases with increasing train speed. Regarding the effect of the carriage location, the coefficient shows an overall increasing trend from the train head to tail.
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| 16. |
- Ouyang, Sheng-de, et al.
(författare)
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Quantum chemical investigations on electron transport characteristics of porphyrin and metal-porphyrin
- 2007
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Ingår i: Chemical Research in Chinese Universities. - 1005-9040 .- 2210-3171. ; 23:1, s. 87-91
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Tidskriftsartikel (refereegranskat)abstract
- Recently, molecular electronics has become increasingly important. By applying the hybrid density functional theory coupled with the Green's function method, the current-voltage characteristics of the molecular junctions composed of gold-porphyrin-gold and gold-copper porphyrin-gold were investigated. The role of the metal coordination effect in organic molecular electron transport was highlighted. Although the thresholds of the bias voltage for both molecules were almost the same, approximately 0.9 V, the metal compound showed a larger increase in current because of the metal-coordination-enhanced molecule-electrode coupling in the frontier molecular orbitals.
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| 17. |
- Pronoitis, Charalampos, et al.
(författare)
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Biobased Polyamide Thermosets : From a Facile One-Step Synthesis to Strong and Flexible Materials
- 2019
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 52:16, s. 6181-6191
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Tidskriftsartikel (refereegranskat)abstract
- Biobased polyamide (PA) thermosets composed of renewable ethylene brassylate were synthesized through a one-step reaction under solvent-free conditions, at 100 degrees C in the presence of an organocatalyst. Under these conditions, thermoset formation times as low as 10 min were achieved. The thermosets were easily prepared as thin, transparent films with high strength, flexibility, and high thermal stability. The ester-to-amine content and formation of ethylene glycol in situ as a byproduct of the reaction were studied and correlated with the final properties of the materials. Crystalline oligoester segments were identified as a result of ring-opening polymerization and were shown to have a beneficial effect on the mechanical properties of the thermosets and endowed shape-memory behavior. In contrast to other routes, employing multistep monomer preparation, harsh conditions, and chlorinated reagents, this procedure contributed to the development of sustainable, functional PA thermosets.
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| 18. |
- Tang, Wen, et al.
(författare)
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Bioactive Surface Modification of Metal Oxides via Catechol-Bearing Modular Peptides : Multivalent-Binding, Surface Retention, and Peptide Bioactivity
- 2014
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 136:46, s. 16357-16367
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Tidskriftsartikel (refereegranskat)abstract
- A series of multivalent dendrons containing a bioactive osteogenic growth peptide (OGP) domain and surface-binding catechol domains were obtained through solid phase synthesis, and their binding affinity to hydroxyapatite, TiO2, ZrO2, CeO2, Fe3O4 and gold was characterized using a quartz crystal microbalance with dissipation (QCM-d). Using the distinct difference in binding affinity of the bioconjugate to the metal oxides, TiO2-coated glass slides were selectively patterned with bioactive peptides. Cell culture studies demonstrated the bioavailability of the OGP and that OGP remained on the surface for at least 2 weeks under in vitro cell culture conditions. Bone sialoprotein (BSP) and osteocalcein (OCN) markers were upregulated 3-fold and 60-fold, respectively, relative to controls at 21 days. Similarly, 3-fold more calcium was deposited using the OGP tethered dendron compared to TiO2. These catechol-bearing dendrons provide a fast and efficient method to functionalize a wide range of inorganic materials with bioactive peptides and have the potential to be used in coating orthopaedic implants and fixation devices.
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| 19. |
- Xu, Huan, et al.
(författare)
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Stereocontrolled Entanglement-Directed Self-Alignment of Poly(lactic acid) Cylindrites
- 2016
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Ingår i: Macromolecular Chemistry and Physics. - : John Wiley & Sons. - 1022-1352 .- 1521-3935. ; 217:23, s. 2567-2575
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Tidskriftsartikel (refereegranskat)abstract
- The concept of stereocontrolled entanglements, in which the tunable H-bonded chiral pairs serve as crosslinks to create topological constraints on the local chain dynamics, is introduced to tailor the crystalline morphology of stereocomplex poly(lactic acid). For the entanglements to be interconnected and activated, poly(d-lactic acid) with statistical branched architecture is incorporated, enabling the construction of 3D association with linear poly(l-lactic acid) chains. With thermodynamically graded disentanglement relaxation for the blends, the profound influence of entanglements on the crystalline morphology is revealed during isothermal crystallization. Orderly aligned cylindrites some with an exceptional length of over 500 μm, resembling the structural features of the classical shish-kebab superstructure, are observed in the blends penetrated with dense entanglement constraints. By contrast, only dendritic spherulites are formed in the highly disentangled blends. The selectively suppressed homo-crystallization by the entanglements offers insights into the contribution of constraints. This bottom-up strategy opens up pathways to engender oriented crystals of long-range order under quiescent conditions, which has potential implications for other chiral polymers.
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| 20. |
- Xu, Yunsheng, et al.
(författare)
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Isosorbide as Core Component for Tailoring Biobased Unsaturated Polyester Thermosets for a Wide Structure- Property Window
- 2018
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 19:7, s. 3077-3085
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Tidskriftsartikel (refereegranskat)abstract
- Biobased unsaturated polyester thermosets as potential replacements for petroleum-based thermosets were designed. The target of incorporating rigid units, to yield thermosets with high thermal and mechanical performance, both in the biobased unsaturated polyester (UP) and reactive diluent (RD) while retaining miscibility was successfully achieved. The biobased unsaturated polyester thermosets were prepared by varying the content of isosorbide, 1,4-butanediol, maleic anhydride, and succinic anhydride in combination with the reactive diluent isosorbide-methacrylate (IM). Isosorbide was chosen as the main component in both the UP and the RD to enhance the rigidity of the formed thermosets, to overcome solubility issues commonly associated with biobased UPs and RDs and volatility and toxicity associated with styrene as RD. All UPs had good solubility in the RD and the viscosity of the mixtures was primarily tuned by the feed ratio of isosorbide but also by the amount of maleic anhydride. The flexural modulus and storage modulus were tailorable by altering the monomer composition The fabricated thermosets had superior thermal and mechanical properties compared to most biobased UP thermosets with thermal stability up to about 250 degrees C and a storage modulus at 25 degrees C varying between 0.5 and 3.0 GPa. These values are close to commercial petroleum-based UP thermosets. The designed tailorable biobased thermosets are, thus, promising candidates to replace their petroleum analogs.
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| 21. |
- Zander, Zachary K., et al.
(författare)
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Control of Mesh Size and Modulus by Kinetically Dependent Cross-Linking in Hydrogels
- 2015
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; , s. n/a-n/a
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Tidskriftsartikel (refereegranskat)abstract
- Kinetically controlled cross-linking processes produce mechanically distinguishable hydrogels using identical precursor chemistry. The oxime ligation demonstrates tunable reaction kinetics with pH and buffer strength, which induce changes in the structural features of hydrogels and determine their mechanical properties. Small-angle neutron scattering and swelling studies provide an insight into how structural properties correlate with mechanical properties for this hydrogel system.
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| 22. |
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| 23. |
- Zheng, Jukuan, et al.
(författare)
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Enhanced Schwann Cell Attachment and Alignment Using One-Pot “Dual Click” GRGDS and YIGSR Derivatized Nanofibers
- 2015
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 16:1, s. 357-363
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Tidskriftsartikel (refereegranskat)abstract
- Using metal-free click chemistry and oxime condensation methodologies, GRGDS and YIGSR peptides were coupled to random and aligned degradable nanofiber networks postelectrospinning in a one-pot reaction. The bound peptides are bioactive, as demonstrated by Schwann cell attachment and proliferation, and the inclusion of YIGSR with GRGDS alters the expression of the receptor for YIGSR. Additionally, aligned nanofibers act as a potential guidance cue by increasing the aspect ratio and aligning the actin filaments, which suggest that peptide-functionalized scaffolds would be useful to direct SCs for peripheral nerve regeneration.
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| 24. |
- Zheng, Jukuan, et al.
(författare)
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Post-Electrospinning “Triclick” Functionalization of Degradable Polymer Nanofibers
- 2015
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Ingår i: ACS Macro Letters. - : American Chemical Society (ACS). - 2161-1653. ; 4:2, s. 207-213
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Tidskriftsartikel (refereegranskat)abstract
- 4-Dibenzocyclooctynol (DIBO) was used as an initiator for the ring-opening copolymerization of ε-caprolactone and 1,4,8-trioxaspiro[4.6]-9-undecanone (TOSUO) resulting in a series of DIBO end-functionalized copolymers. Following deprotection of the ketone group, the polymers were derivatized with aminooxyl-containing compounds by oxime ligation. Mixtures of keto- and alkyne-derivatized polymers were co-electrospun into well-defined nanofibers containing three separate chemical handles. Strain-promoted azide alkyne cycloaddition (SPAAC), oxime ligation, and copper-catalyzed azide alkyne cycloaddition (CuAAC) were used to sequentially functionalize the nanofibers first with fluorescent reporters and then separately with bioactive Gly-Arg-Gly-Asp-Ser (GRGDS), BMP-2 peptide, and dopamine. This translationally relevant approach facilitates the straightforward derivatization of diverse bioactive molecules that can be controllably tethered to the surface of nanofibers.
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