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- Jonsson, Amanda, et al.
(författare)
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Bioelectronic neural pixel: Chemical stimulation and electrical sensing at the same site
- 2016
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 113:34, s. 9440-9445
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Tidskriftsartikel (refereegranskat)abstract
- Local control of neuronal activity is central to many therapeutic strategies aiming to treat neurological disorders. Arguably, the best solution would make use of endogenous highly localized and specialized regulatory mechanisms of neuronal activity, and an ideal therapeutic technology should sense activity and deliver endogenous molecules at the same site for the most efficient feedback regulation. Here, we address this challenge with an organic electronic multifunctional device that is capable of chemical stimulation and electrical sensing at the same site, at the single-cell scale. Conducting polymer electrodes recorded epileptiform discharges induced in mouse hippocampal preparation. The inhibitory neurotransmitter, γ-aminobutyric acid (GABA), was then actively delivered through the recording electrodes via organic electronic ion pump technology. GABA delivery stopped epileptiform activity, recorded simultaneously and colocally. This multifunctional “neural pixel” creates a range of opportunities, including implantable therapeutic devices with automated feedback, where locally recorded signals regulate local release of specific therapeutic agents.
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- Unalan, Ilke Uysal, et al.
(författare)
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Exceptional oxygen barrier performance of pullulan nanocomposites with ultra-low loading of graphene oxide
- 2015
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 26:27
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Tidskriftsartikel (refereegranskat)abstract
- Polymer nanocomposites are increasingly important in food packaging sectors. Biopolymer pullulan is promising in manufacturing packaging films or coatings due to its excellent optical clarity, mechanical strength, and high water-solubility as compared to other biopolymers. This work aims to enhance its oxygen barrier properties and overcome its intrinsic brittleness by utilizing two-dimensional planar graphene oxide (GO) nanoplatelets. It has been found that the addition of only 0.2 wt% of GO enhanced the tensile strength, Young's modulus, and elongation at break of pullulan films by about 40, 44 and 52%, respectively. The light transmittance at 550 nm of the pullulan/GO films was 92.3% and haze values were within 3.0% threshold, which meets the general requirement for food packaging materials. In particular, the oxygen permeability coefficient of pullulan was reduced from 6337 to 2614 mL mu mm(-2) (24 h(-1)) atm(-1) with as low as 0.05 wt% of GO loading and further to 1357 mL mu mm(-2) (24 h(-1)) atm(-1) when GO concentration reached 0.3 wt%. The simultaneous improvement of the mechanical and oxygen barrier properties of pullulan was ascribed to the homogeneous distribution and prevalent unidirectional alignment of GO nanosheets, as determined from the characterization and theoretical modelling results. The exceptional oxygen barrier properties of pullulan/ GO nanocomposites with enhanced mechanical flexibility and good optical clarity will add new values to high performance food packaging materials.
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