Abstract: The immobilization methods of biomolecules into nanostructured polypyrroles, namely, adsorption, entrapment during the electropolymerization process, covalent binding, and molecular imprint are systematically summarized based on the latest literatures. The operational principle and detective capacities of the nanostructured polypyrroles-based amperometric biosensors such as enzyme biosensor, nucleic acid biosensor, and immunosensor are also highly reviewed. It is pointed out that the nanostructured polypyrroles with excellent biocompatibility, selective permeability, interference immunity, and large specific surface area significantly favor enhancing loading capacity and keeping bioactivity of biomoleculs, resulting in higher sensitivity, selectivity, and environmental stability biosensors. Composite of polypyrrole and some metal nanoparticles or carbon nanotubes exhibits synergistic effect and remarkably enhances sensitivity in current. After nanosturctrued polypyrroles decorated, the electrocatalytic activity and detection limit of electrode are improved by 2 -4 orders and 5.0 x 10(4) times, respectively. Biosensors based on nanostructured polypyrroles have shown great potential applications in the biomedicine, clinical diagnosis, environmental monitoring, and food analysis.
Abstract: O-Lauroyl chitosan/poly(l-lactide) (OCS/PLLA) blend membranes with different compositions were prepared by solution-casting approach using chloroform as common solvent. The experimental results of FT-IR, DSC and WAXD indicated that inter-association hydrogen-bond interactions existed between OCS and PLLA in the blend membranes. And SEM observation confirmed that the blend membranes with suitable compositions were compatible
Abstract: The properties of N,N-dialkyl chitosan monolayers and corresponding vesicles have been studied by LB technique and drug-release experiment. With increasing molecular weight of chitosan backbone and/or length of alkyl chain, both the compressibility and collapse pressure of N,N-dialkyl chitosan monolayer are enhanced. The experiments on drug-release behavior of N,N-dialkyl chitosan vesicles show that the drug-release rate and the equilibrium drug-release ratio are decreased with increasing the compressibility of corresponding monolayer. It is worth noticing that there is a linear relationship between the compressibility of N,N-dialkyl chitosan monolayers and the equilibrium drug-release ratio of the vesicles.
Abstract: Blue light-emitting oligotriphenylene nanofibers are synthesized by oxidizing triphenylene using ferric chloride. By adjusting the monomer concentration, the acid used, and the temperature employed, the average diameter and length of the nanofibers can be readily tuned from 50 to 200 nm and 0.5 to 5 μm, respectively. Structural characterization, electrical conductivity, thermal stability, and fluorescence of oligotriphenylene, along with a proposed nanofiber formation mechanism, are presented. Both oligotriphenylene nanofiber dispersions and oligotriphenylene/polysulfone composite films are developed as fluorescent sensors for detecting traces of nitro-based explosives including nitromethane, nitrobenzene, and 2,4,6-trinitrophenol, as well as an electron-deficient metal ion, Fe(III). The sensors exhibit much better selectivity and sensitivity compared to conventional sensors, with detection limits down to 1.0 nm with a detection range covering â¼4 orders of magnitude. The detection mechanism of the fluorescent sensors is also disscussed.
Abstract: A novel amphiphilic chitosan, O,O-dilong chain acyl chitosan (OCS), was applied to prepare self- assembled vesicles for DDS and OCS/PLLA blend for tissue engineering scaffold. The study on morphology, drug-releasing behavior of the vesicles, and the bio-experiments of OCS vesicles and OCS/PLLA blend elucidate the relative results are similar to NCS vesicles and NCS/PLLA blend.
