POSITIVELY CHARGED POLY(LACTIC ACID) FIBER MAT AND BIOLOGICAL RESPONSE

Abstract

Poly(lactic acid) (PLA) has been widely used in several applications including biomedical applications. In this work the hydrophilicity of PLA was enhanced by attaching positively charged quaternary ammonium groups at both sides of polymer chain ends. The positively charged PLA or PLAdi+ was synthesized by two-step synthesis method. First, PLA having carboxylic groups on both chain ends (PLAdiCOOH) was prepared via polycondensation of L-lactic acid in the presence of succinic acid. Then the carboxyl groups of PLAdiCOOH were attached to glycidyl trimethylammonium chloride (GTMAC) to form PLAdi+ having Mn of 3,670 Da, It was then blended with a commercialized PLA (Mn of 60,000 Da) with mass ratio of PLA:PLAdi+ 100:0, 100:10, 100:30 100:50 and 100:70. The polymer blends were then used to produce non-woven fiber mats by electrospinning technique. The diameter of PLA/PLAdi+ fiber was found to be decreased from 365±83 nm to 109±29 nm with mass ratio of PLA:PLAdi+ 100:70. The addition of PLAdi+ also caused a reduction of air-water contact angle of the fiber mats from 135±1º (PLA) down to 50±3º and 144±5º (PLA) down to 55±3º measured by static and dynamic water contact angle, respectively. Moreover, the electrospun fiber mats were further evaluated for antibacterial testing and fibroblast L929 cell adhesion and proliferation. All electrospun fiber mats, however, did not possess antibacterial activity. But the fiber mats of PLA/PLAdi+ and PLA/PLAdiCOOH with mass ratio of PLA:PLAdi+ (100:70) were found to be an acceptable material for fibroblast cell culture.