Thesis (M.Eng.)--Chulalongkorn University, 2010

In this study, chitosan nanofibers were fabricated by electrospinning technique. It is an objective of this research to investing the feasibility of pure chitosan nanofibers fabrication via the electrospinning technique and to investigate bacterial attachment and cells viability of Gram-positive Brevibacillus agri strain 13 and Gram-negative Acinetobacter baylyi strain GFJ2 on the electrospun nanofibers. The fabrication of pure chitosan nanofibers was found to be unsuccessful. Only sprayed droplets were obtained. In order to obtain nanofibers, either the addition of polyvinyl alcohol (PVA) as a spinning aid or the hydrolysis of chitosan is needed. Formability, morphology and size distribution of the electrospun nanofibers using various preparation conditions are reported. For the results of bacterial attachment and viability, it has been proven that attachment of Gram-negative bacteria on chitosan is more effective than Gram-positive bacteria. Fluorescence microscopy results showed the optimal of incubation time of bacteria to be 12 h to get the highest fraction of live cells on the chitosan surface. Increasing hydrolysis time results in increased cell attachment and viability on the surface by the role of deacetylation and molecular weight reduced by hydrolysis reaction. Moreover, the chitosan in nanofibers form shows better cell attachment than chitosan in the form of films.