A NOVEL METHOD OF STUDYING POLYMER BIODEGRADATION

A novel combination of laser light scattering (LLS) and the micronizat ion of a water-insoluble polymer into narrowly distributed nanoparticl es stable in water has provided not only an accurate, reliable and mic roscopic method to study polymer biodegradation, but also a novel and fast way to evaluate the biodegradability of a given polymer. Using po ly(epsilon-caprolactone) (PCL) as a typical example, we have shown tha t its biodegradation time can be shortened by a factor of more than 10 (3) times in comparison with the time required to biodegrade a thin fi lm (10 x 10 x 0.1 mm(3)). Moreover, the biodegradation kinetics can be in-situ monitored in terms of the decrease of the time-average scatte ring intensity and the particle number. A comparison of static and dyn amic LLS results revealed that the enzyme, Lipase Pseudomonas, ''eats' ' the PCL nanoparticles in an one-by-one manner and the enzymatic biod egradation of PCL follows a zero-order kinetics. (C) 1998 Elsevier Sci ence Ltd. All rights reserved.