Implant associated infections are of increasing importance. To minimize the risks of implant-associated infections recent biomedical strategies have led to the modification of the medical device surfaces. The modifications are in the terms of increasing surface biocompatibility and decreasing bacterial adherence, which can be achieved by applying a coating of biocompatible polymer onto the said surfaces. Entrapping anti-infective agents in a polymer matrix provides an approach to kill bacteria and combat the possibility of any residual infection. We have prepared a biodegradable polyester urethane coat for implant materials, which have the property to accommodate antibiotics within itself. These polyurethane coating materials were characterized by FTIR spectroscopy, swelling property in SBF, gravimetric analysis, drug release, and biocompatibility study. Drug release rates, bacterial colonization and morphological features were also evaluated to predict and understand the antimicrobial activity of these delivery systems. Drug release characteristics were investigated and the physico-chemical mechanisms of the delivery were discussed. Results suggest that the polyester urethane can be used as an implant coating material and can be used as a matrix for the sustained delivery of anti-infective agent.

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In this paper, a surface potential based compact model for organic thin-film transistors (OTFTs) including both tail and deep trap states across the band gap is presented and benchmarked against measured data from high-performance dinaphtho thieno thiophene (C 10 -DNTT) based test devices. This model can accurately describe the OTFT test-structure current from week to strong inversion regime.

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A compact surface potential based model for organic thin-film transistors (OTFTs), including both tail and deep trap states across the band gap, is reported. The model has been developed on the basis of a complete surface potential approach for undoped-body OTFTs. Accurate surface potentials are calculated by explicitly including the floating backside potential that varies with applied biases. A pseudo-2D resistor model is developed to capture the structural features of the OTFT. The resistor model considers, in particular, the effects originating from a bias dependent 2D current flow in the channel region and results in accurate reproduction of the electrical characteristics. The fitting capability of the developed OTFT model is verified against measured high-performance dinaphtho thieno thiophene (DNTT) based field-effect transistor data. Accurate reproduction of the current characteristics of the OTFT test structures is verified from a week to a strong inversion regime.

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