RESUMEN
In this paper, l-lysine-based materials which are rich in amino groups were synthesized through a chemical reaction. The polyaniline/polyacrylonitrile (PANI/PAN) thin film and PANI/PAN nanocomposite (NC) thin films doped with l-lysine based materials were obtained by electrospinning and in situ polymerization of aniline. The gas sensing properties of the PANI/PAN thin film and PANI/PAN NC thin films doped with l-lysine based materials towards NH3, ethanol, acetone, chloroform and DMF were examined at room temperature. The experimental results reveal that the PANI/PAN/l-lysine based nanogel (4-Lys-4 nanogel) NC thin film exhibited a highly selective response toward NH3 at room temperature with improved response kinetics. The PANI/PAN/4-Lys-4 nanogel NC thin film showed the response of 5.5 with response and recovery times of 22 s and 15 s, respectively, toward 100 ppm NH3, and the detection limit of 2.2 ppm. This response and recovery are quite fast compared with the reported studies based on PANI doped with other materials. The enhanced response could be attributed to the large surface area, the core-shell structure of the nanofibers and improved charge transfer as a result of a certain amount of amino groups doping PANI. Our results clearly indicate that the PANI/PAN/4-Lys-4 nanogel NC thin film could effectively be used for the practical room temperature NH3 sensing application with quite fast response and recovery properties. At the same time, a new application of 4-Lys-4 nanogel on sensors is supplied.
RESUMEN
In this study, a promising preparation strategy for antibacterial silk sutures with an l-lysine based nanogel grafting is reported. The triclosan-loaded nanogels (NGTLs) were fabricated by the convenient enzymatic degradation of macrogels, namely, triclosan-loaded macrogel, degrading into NGTLs triggered by the trypsin. Nanogels, about 60 nm and 90 nm in diameter, were obtained after 7 days of biodegradation in the enzyme solution. Triclosan maintained a sustained release period over 260 hours in trypsin solution with the concentration of 0.1 mg mL-1. Triclosan-loaded nanogel grafted silk sutures (TLNGSs) were characterized by an antibacterial activity assessment. Our results showed that TLNGS had long-term efficacy against pathogens such as S. aureus and E. coli. In particular, these TLNGSs had a relative decreased stable size of inhibition zones on agar plates in the first four days. The antibacterial activity could be sufficient evidence of the prevention of potential early wound infections. The mechanical strength tests indicated negligible influence on TLNGSs compared to commercial ones. The novel antibacterial silk sutures showed acceptable in vitro cytotoxicity according to ISO 10993-5. This novel biocompatible and biodegradable nanogel grafting to silk sutures provides an effective and universal approach for the treatment of bacterial infections.