Biomaterials for drug delivery, scaffolds

Researchers have designed new nanosized hybrid materials using natural polymers and layered silicates. The new materials can deliver drugs and provide scaffolds for tissue growth1.

Polyhydoxyalkanoates (PHA) are naturally occurring, biodegradable and biocompatible polymers suitable for tissue engineering and drug delivery. Such polymers are used in bioimplants that

don't need surgical removal. However, the need for a biomaterial that also releases drugs and aids tissue growth has been long felt. The researchers, trying to create such a material,

prepared a new class of nanohybrids by mixing a polymer hydroxybutyrate-co-valerate (PHBV) and layered silicate modified with organic compounds (nanoclays). They used two types of nanoclays

— 30B and 15 — to produce two types of nanohybrids — PHBV-30B and PHBV-15A. The researchers carried out biodegradation studies using the soil bacteria _Pseudomonas stutzeri_ . The bacterium

secreted an enzyme that degraded the nanohybrids. The biodegradation rate was enhanced in the presence of 15A nanoclay while it was dramatically suppressed in the presence of 30B nanoclay as

compared to pure PHBV. In studies with cervical cancer cells, they found that the cells survived and grew on top of the nanohybrid films. The shape of cells (elliptical) was better in

nanohybrids than that of pure polymer (nearly spherical), indicating that the nanohybrids were more biocompatible. The nanohybrids also demonstrated sustained drug release in studies with

ciprofloxacin hydrochloride. The authors of this work are from: _ Institute of Technology and Banaras Hindu University, Varanasi, India; and School of Engineering and University of Guelph,

Ontario, Canada _