Nondestructive testing of defects in adhesive joints

Abstract
Protein functionalized polysaccharide nano particles for novel
applications
T.Emilia Abraham
Chemical Sciences & Technology Division,
National Institute for Interdisciplinary Science & Technology (NIIST), CSIR,
Thiruvananthapuram-695019
E-mail:emiliatea@gmail.com
There has been growing interest in the use of natural polysaccharides for biomedical
applications, drug delivery vehicles, as minimally invasive scaffolds for tissue engineering,
because of their non toxicity, biocompatibility, biodegradability, low interfacial tension and high
molecular and oxygen permeability. By exploiting these features it may be possible to mimic
features of the natural extracellular matrix, and control tissue structure and cellular functions.
Protein/peptide oral drug delivery is complicated process mainly due to poor intrinsic protein
permeability as a result of large molecular weight, degradation by proteolytic enzymes in the
stomach and in the small intestine, and chemical instability. Protein functionalized micro and
nano particles are very versatile and were made to overcome this problem. Low molecular weight
chitosan, guar gum, were used for the preparation of nano particles using precipitation and ionic
cross linking method and was then linked to the enzyme (subtilisin) by glutaraldehyde coupling.
Polysaccharides having a molecular mass of 8 to 36 KDa gave high-quality nano composite
spherical particles of 100-500 nm size, with a good poly dispersity index of 0.1- 0.7. Poly
saccharides having a molecular mass greater than 50 KDa gave micro particles and vesicles of
more than 1 microns as indicated by Dynamic laser light scattering, SEM, and TEM studies. The
optimum pH of the polysaccharide nanoparticle immobilized enzyme was shifted to 8.0 from 7.0,
whereas there was no change in the optimum temperature. The immobilized enzyme shows better
affinity to the substrate (casein) with a lower K value of 4.097x10
M -5 than the native subtilisin
which is 3.30x10 -4 . These composite catalytic nano particles are having excellent activity, pH
sensitivity and stability which make them suitable for oral drug delivery, tissue scaffolds,
microreactors or for cosmetic applications.
1. Introduction:
There is significant interest in the protein functionalized nanosized particles; with
potential applications ranging from biosensors [1-3] enzymatic bioreactors [4] delivery of
sensitive drugs [5] nano biochips and membranes for bioseparations [6], surface coatings,