Fabrication of novel biofibers by coating silk fibroin with chitosan impregnated with silver nanoparticles.

Nanoparticle based agents often applied as coatings on biomaterials have shown promise in delivering the improved sterility against variety of microbes. In the present study, silk fibers (SF) were coated with chitosan impregnated with silver nanoparticles (Ag-C-SF). These Ag-C-SF fibers were characterized using scanning electron microscopy (SEM) with energy dispersive X-ray analysis, atomic force microscopy (AFM), Infra Red spectroscopy, Thermogravimetric Analysis and Microbiological assay techniques. AFM studies have confirmed the nano sized silver particles in chitosan solution; SEM pictures have exhibited the coating of chitosan along with silver nanoparticles on the silk fibroin. The modified fibers have also shown anti-microbial activity and improved thermal stability. The Ag-C-SF fibers may be explored as wound dressing and tendon reconstruction material in future.

Chitosan and its derivatives for gene delivery.

Gene delivery can particularly be used for the treatment of diseases by the insertion of genetic materials (DNA and RNA) into mammalian cells either to express new proteins or to prevent the expression of existing proteins. Chitosan, a natural polymer is nontoxic, biocompatible, and biodegradable and it is used as a support material for gene delivery. However, practical use of chitosan has been mainly limited to its unmodified forms, and thus modified chitosans can be used for the wide range of biomedical applications including the interaction and intracellular delivery of genetic materials. In this context, this review paper provides the recent development on chitosan derivatives available for gene delivery.

Preparation, characterization and evaluation of a biopolymeric gold nanocomposite with antimicrobial activity.

The present study describes the antimicrobial activity of C-AuNp-Amp (chitosan-capped gold nanoparticles coupled with ampicillin). C-AuNp-Amp was synthesized using the wet precipitation method and characterized using FTIR (Fourier-transform IR) spectroscopy and AFM (atomic force microscopy) techniques. The optimal level of ampicillin concentration that couples with the C-AuNp nanocomposite was determined by using UV-visible spectroscopy. The agar-well diffusion method was used to evaluate the antimicrobial activity, and the broth dilution assay was used to determine the MIC (minimum inhibitory concentration). The size of the ellipsoidal C-AuNp-Amp particles was found to be in the range of 50-100 nm. The FTIR spectrum confirms the bonding between amino groups of chitosan and carboxylic groups of ampicillin. The maximum coupling of ampicillin with C-AuNp was found to be 4.07 mg/10 ml. These results revealed the antimicrobial efficacy of C-AuNp-Amp and a 2-fold increase in activity was achieved when compared with that of free ampicillin. By reducing the antibiotic dosage to 50%, the side effects produced by antibiotics can be minimized.