| 1. |
- Bolin, Maria, et al.
(författare)
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Active Control of Epithelial Cell-Density Gradients Grown Along the Channel of an Organic Electrochemical Transistor
- 2009
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Ingår i: ADVANCED MATERIALS. - : Wiley. - 0935-9648 .- 1521-4095. ; 21:43, s. 4379-
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Tidskriftsartikel (refereegranskat)abstract
- Complex patterning of the extracellular matrix, cells, and tissues under in situ electronic control is the aim of the technique presented here. The distribution of epithelial cells along the channel of an organic electrochemical transistor is shown to be actively controlled by the gate and drain voltages, as electrochemical gradients are formed along the transistor channel when the device is biased.
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| 2. |
- Bolin, Maria, et al.
(författare)
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Nano-fiber scaffold electrodes based on PEDOT for cell stimulation
- 2009
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Ingår i: SENSORS AND ACTUATORS B-CHEMICAL. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 142:2, s. 451-456
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Tidskriftsartikel (refereegranskat)abstract
- Electronically conductive and electrochemically active 3D-scaffolds based on electrospun poly(ethylene terephthalate) (PET) nano-fibers are reported. Vapour phase polymerization was employed to achieve an uniform and conformal coating of poly(3,4-ethylenedioxythiophene) doped with tosylate (PEDOT:tosylate) on the nano-fibers. The PEDOT coatings had a large impact on the wettability, turning the hydrophobic PET fibers super-hydrophilic. SH-SY5Y neuroblastoma cells were grown on the PEDOT coated fibers. The SH-SY5Y cells adhered well and showed healthy morphology. These electrically active scaffolds were used to induce Ca2+ signalling in SH-SY5Y neuroblastoma cells. PEDOT:tosylate coated nano-fibers represent a class of 3D host environments that combines excellent adhesion and proliferation for neuronal cells with the possibility to regulate their signalling.
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| 3. |
- Brouwers, Lisa, 1967-, et al.
(författare)
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Economic consequences to society of pandemic H1N1 influenza 2009 : preliminary results for Sweden
- 2009
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Ingår i: Eurosurveillance. - : European Centre for Disease Control and Prevention (ECDC). - 1025-496X .- 1560-7917. ; 14:37, s. 19333-
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Tidskriftsartikel (refereegranskat)abstract
- Experiments using a microsimulation platform show that vaccination against pandemic H1N1 influenza is highly cost-effective. Swedish society may reduce the costs of pandemic by about SEK 2.5 billion (approximately EUR 250 million) if at least 60 per cent of the population is vaccinated, even if costs related to death cases are excluded. The cost reduction primarily results from reduced absenteeism. These results are preliminary and based on comprehensive assumptions about the infectiousness and morbidity of the pandemic, which are uncertain in the current situation.
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| 4. |
- Hederos, Carl-Axel, et al.
(författare)
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Comparison of clinically diagnosed asthma with parental assessment of children's asthma in a questionnaire
- 2007
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Ingår i: Pediatric Allergy and Immunology. - : Wiley. - 0905-6157 .- 1399-3038. ; 18:2, s. 135-141
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological evaluations of the prevalence of asthma are usually based on written questionnaires (WQs) in combination with validation by clinical investigation. In the present investigation, we compared parental assessment of asthma among their preschool children in response to a WQ with the corresponding medical records in the same region. An International Study of Asthma and Allergies in Childhood (ISAAC)-based WQ was answered by 75% of the parents of 6295 children aged 1–6 yr. Clinically diagnosed asthma, recorded in connection with admissions to the hospital or a visit to any of the outpatient clinics in the same region, were analysed in parallel. Finally, a complementary WQ was sent to the parents of children identified as asthmatic by either or both of this approaches. In response to the WQ 5.9% were claimed to suffer from asthma diagnosed by a doctor. According to the medical records, the prevalence of clinically diagnosed asthma was 4.9%. The estimated prevalence among children requiring treatment for their asthma was 4.4%. The sensitivity of the WQ was 77%, the specificity 97.5%. In the 1–2 yr age group the sensitivity was only 22%. This WQ was able to identify 54% of the children with a medical record of asthma. Forty percent of the children claimed by their parents to be asthmatic had no medical record of asthma. An ISAAC-based parentally completed WQ provided an acceptable estimation of the prevalence of asthma in children 2–6 yr of age, although only half of the individual patients identified in this manner are the same as those identified clinically.
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| 5. |
- Isaksson, Joakim, et al.
(författare)
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Electronic Control of Ca2+ Signalling in Neuronal Cells using an Organic Electronic Ion Pump
- 2007
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-1122 .- 1476-4660. ; 6:9, s. 673-679
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Tidskriftsartikel (refereegranskat)abstract
- Cells and tissues use finely regulated ion fluxes for their intra- and intercellular communication. Technologies providing spatial and temporal control for studies of such fluxes are however, limited. We have developed an electrophoretic ion pump made of poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulphonate) (PEDOT:PSS) to mediate electronic control of the ion homeostasis in neurons. Ion delivery from a source reservoir to a receiving electrolyte via a PEDOT:PSS thin-film channel was achieved by electronic addressing. Ions are delivered in high quantities at an associated on/off ratio exceeding 300. This induces physiological signalling events that can be recorded at the single-cell level. Furthermore, miniaturization of the device to a 50-um-wide channel allows for stimulation of individual cells. As this technology platform allows for electronic control of ion signalling in individual cells with proper spatial and temporal resolution, it will be useful in further studies of communication in biological systems.
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| 6. |
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| 7. |
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| 8. |
- Sonesson, Andreas, et al.
(författare)
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A comparison between dual polarization interferometry (DPI) and surface plasmon resonance (SPR) for protein adsorption studies
- 2007
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Ingår i: Colloids and Surfaces B. - : Elsevier BV. - 0927-7765 .- 1873-4367. ; 54, s. 236-240
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Tidskriftsartikel (refereegranskat)abstract
- This work was performed with the aim of comparing protein adsorption results obtained from the recently developed dual polarization interferometry (DPI) with the well-established surface plasmon resonance (SPR) technique. Both techniques use an evanescent field as the sensing element but completely different methods to calculate the adsorbed mass. As a test system we used adsorption of the lipase from Thermomyces lanuginosus (TLL) on C18 surfaces. The adsorbed amount calculated with both techniques is in good agreement, with both adsorption isotherms saturating at 1.30–1.35 mg/m2 at TLL concentrations of 1000nM and above. Therefore, this supports the use of both SPR and DPI as tools for studying protein adsorption, which is very important when comparing adsorption data obtained from the use different techniques. Due to the spot sensing in SPR, this technique is recommended for initial kinetic studies, whereas DPI is more accurate when the refractive index and thickness of the adsorbed layer is of more interest.
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| 9. |
- Sonesson, Andreas, et al.
(författare)
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Adsorption and activity of Thermomyces lanuginosus lipase on hydrophobic and hydrophilic surfaces measured with dual polarization interferometry (DPI) and confocal microscopy
- 2008
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Ingår i: Colloids and Surfaces B. - : Elsevier BV. - 0927-7765 .- 1873-4367. ; 61:2, s. 208-215
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption and activity of Thermomyces lanuginosus lipase (TLL) was measured with dual polarization interferometry (DPI) and confocal microscopy at a hydrophilic and hydrophobic surface. In the adsorption isotherms, it was evident that TLL both had higher affinity for the hydrophobic surface and adsorbed to a higher adsorbed amount (1.90 mg/m(2)) compared to the hydrophilic surface (1.40-1.50 mg/m(2)). The thickness of the adsorbed layer was constant (similar to 3.5 nm) on both surfaces at an adsorbed amount > 1.0 mg/m(2), but decreased on the hydrophilic surface at lower surface coverage, which might be explained by partially unfolding of the TLL structure. However, a linear dependence of the refractive index of the adsorbed layer on adsorbed amount of TLL on C18 surfaces indicated that the structure of TLL was similar at low and high surface coverage. The activity of adsorbed TLL was measured towards carboxyfluorescein diacetate (CFDA) in solution, which upon lipase activity formed a fluorescent product. The surface fluorescence intensity increase was measured in a confocal microscope as a function of time after lipase adsorption. It was evident that TLL was more active on the hydrophilic surface, which suggested that a larger fraction of adsorbed TLL molecules were oriented with the active site facing the solution compared to the hydrophobic surface. Moreover, most of the activity remained when the TLL surface coverage decreased. Earlier reports on TLL surface mobility on the same surfaces have found that the lateral diffusion was highest on hydrophilic surfaces and at low surface coverage of TLL. Hence, a high lateral mobility might lead to a longer exposure time of the active site towards solution, thereby increasing the activity against a water-soluble substrate.
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| 10. |
- Sonesson, Andreas, et al.
(författare)
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Adsorption and mobility of a lipase at a hydrophobic surface in the presence of surfactants
- 2006
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 22:13, s. 5810-1817
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Tidskriftsartikel (refereegranskat)abstract
- With the aim of being able to manipulate the processes involved in interfacial catalysis, we have studied the effects of a mixture of nonionic/anionic surfactants, C12E6/LAS (1: 2 mol %), on the adsorption and surface mobility of a lipase obtained from Thermomyces lanuginosus (TLL). Surface plasmon resonance (SPR) and ellipsometry were used to analyze the competitive adsorption process between surfactants and TLL onto hydrophobic model surfaces intended to mimic an oily substrate for the lipase. We obtained the surface diffusion coefficient of a fluorescently labeled TLL variant on silica silanized with octadecyltrichlorosilane (OTS) by fluorescence recovery after photobleaching (FRAP) on a confocal laser scanning microscope. By means of ellipsometry we calibrated the fluorescence intensity with the surface density of the lipase. The TLL diffusion was measured at different surface densities of the enzyme and at two time intervals after coadsorption with different concentrations of C12E6/LAS. The surfactant concentrations were chosen to represent concentrations below the critical micelle concentration (CMC), in the CMC region, and above the CMC. The apparent TLL surface diffusion was extrapolated to infinite surface dilution, D-0. We found that the presence of surfactants strongly modulated the surface mobility of TLL: with D-0 = 0.8 x 10(-11) cm(2)/s without surfactants and D-0 = 13.1 x 10(-11) cm(2)/s with surfactants above the CMC. The increase in lipase mobility on passing the CMC was also accompanied by a 2- fold increase in the mobile fraction of TLL. SPR analysis revealed that surface bound TLL was displaced by C12E6/LAS in a concentration-dependent manner, suggesting that the observed increase in surface mobility imparts bulk-mediated diffusion and so-called rebinding of TLL to the surface. Our combined results on lipase/surfactant competitive adsorption and lipase surface mobility show how surfactants may play an important role in regulating interfacial catalysis from physiological digestion to technical applications such as detergency.
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