Page 171 - Demo

SECTION I: MOLECULAR GENETIC ENGINEERING AND BIOCHEMICAL TECHNOLOGY 1752. MATERIALS AND METHODS2.1. MaterialsChitosan (CS, Mw~100 kD; degree of deacetylation = 99 %) was purchased from Sigma-Aldrich (USA). Polylactic acid (PLA, Mw 200 kD), Polyethylene glycol (PEG, Mw = 600 Da), acetic acid (%u2265 99.5%), chloroform (%u2265 99.5%) were purchased from Merck (Germany). Capsaicin (%u2265 95%) (obtained from chili peppers) was supplied by Department of Pharmaceutical Chemistry and Organic Synthesis, Institute of Natural Products Chemistry, VAST, Vietnam. All the chemicals were used without further treatment. Bacterial strains including Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, Bacillus subtillis subsp. spizizenii ATCC 6633, Staphylococcus aureus subsp. aureus ATCC 25923, Aspergillus niger ATCC 6275, Fusarium oxysporum ATCC 7601, Candida albicans ATCC 10231, Saccharomyces cerevisiae VTCC%u2013Y%u201362 were obtained from Experimental Biology Department, Institute of Natural Products Chemistry, VAST, Vietnam. These strains were maintained on nutrient agar and stored at 4%u00b0C. 2.2. Fabrication of electrospun nanofibers CS/PLA/PEG loaded capsaicinPreparation of polymer solutions0.1 g of CS was completely dissolved in 90% acetic acid solution at 50oC to give CS solution at the concentration of 2% (w/v) (solution 1). PLA (0.75 g) and PEG (0.05 g) was dissolved in chloroform at 40oC to obtain the solution with the concentration of PLA and PEG of 15% and 1% (w/v), respectively (solution 2). An appropriate amount of capsaicin (0.123 g) was then added to solution 2 to achieve solution 3. Solution 1 was added slowly into solution 3 at the ratio of 1:1 (v:v) with magnetic stirring to obtain a homogeneous solution for electrospinning (solution 4).