Microfluidic fabrication of alendronate-loaded chitosan nanoparticles for enhanced osteogenic differentiation of stem cells

A central challenge in the development of drug-encapsulated polymeric nanoparticles is the inability to control the mixing processes required for their synthesis resulting in variable nanoparticle physicochemical properties. Nanoparticles may be developed by mixing and nanoprecipitation of polymers and drugs dissolved in organic solvents with nonsolvents. We used rapid and tunable mixing through hydrodynamic flow focusing in microfluidic channels to control nanoprecipitation of poly(lactic- co-glycolic acid)- b-poly(ethylene glycol) diblock copolymers as a model polymeric biomaterial for drug delivery. We demonstrate that by varying (1) flow rates, (2) polymer composition, and (3) polymer concentration we can optimize the size, improve polydispersity, and control drug loading and release of the resulting nanoparticles. This work suggests that microfluidics may find applications for the development and optimization of polymeric nanoparticles in the newly emerging field of nanomedicine.

Chitin is one of the most abundant polysaccharide found on earth. The deacetylated form of chitin viz. chitosan has been reported for its various important pharmacological properties and its role in tissue engineering and regenerative medicine is also well documented. Chitosan based bone graft substitutes are biocompatible, biodegradable, osteoconductive, osteoinductive and structurally similar to bone, with excellent mechanical strength and cost effectiveness. Chitosan based hydrogels and wound healing bandages have also found a great market in the field of medicine. More recently, chitosan has gained popularity for its use as a matrix molecule for drug delivery and also finds an upcoming utility in the area of dentistry. The present article has tried to review the latest research on chitosan based tissue engineering constructs, drug delivery vehicles as well as dental care products. An attempt has also been made to discuss the various modifications of chitosan that enhance its use for a given set of applications which would pave a way for future applied research in the field of biomedical innovation and regenerative medicine.