In-situ monitoring of drug release from therapeutic eluting polyelectrolyte multilayers under static and dynamic conditions

Abstract

The release profiles of gentamicin sulfate (GS) from [chitosan (CHI)/poly(acrylic acid) (PAA)/GS/PAA] n polyelectrolyte multilayers were investigated in situ using an innovative lab-on-fiber (LOF) optofluidic platform that mimics physiologically relevant fluid flow in a microenvironment. The LOF was constructed by enclosing in a flowenabled and optically coupled glass capillary a long-period fiber grating both as a substrate for LbL growth of [CHI/PAA/GS/PAA] n and a measurement probe for GS release. We show that the LOF is very robust in monitoring the construction of the [CHI/PAA/GS/PAA] n multilayers at monolayer resolution as well as evaluating the rate of GS release with high sensitivity. The release processes in the LOF under static and a range of dynamic conditions are evaluated, showing a faster release under dynamic condition than that under static condition due to the varying circumstance of GS concentration gradient and the effect of flow-induced shear at the medium-multilayer interface. The LOF platform has the potential to be a powerful test bed to facilitate the design and evaluation of drug-eluting polyelectrolyte thin films for their clinical insertion as part of patient care strategy.