Size-dependent optical properties of bio-compatible ZnS:Mn nanocrystals and their application in the immobilisation of trypsin

作者：Augustine M Sajimol^*; Ali P P Manzur; Sapna K; Elyas K K; Jayalekshmi S

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2013, 108: 223-228.

DOI：10.1016/j.saa.2013.01.066

• Chitosan
• Bio-compatible
• Chemical capping
• Trypsin
• Immobilisation

Chitosan capped zinc sulphide nanocrystals doped with manganese (ZnS:Mn) have been synthesised by chemical capping co-precipitation method and structurally characterised by XRD, TEM and EDXS techniques. The dependence of optical properties on the size of these bio-compatible ZnS:Mn nanocrystals was investigated by UV/Vis and photoluminescence (PL) spectroscopic techniques in aqueous solvents. A variation in molar concentration of the precursor, sodium sulphide, from 0.125 to 0.01 mol L-1 is accompanied by a decrease in particle size. The excitonic peak in the UV/Vis spectra is found to be blue shifted with a decrease in size of the nanocrystals due to confinement effects. In the present study, trypsin was immobilised onto ZnS:Mn nanocrystals using glutaraldehyde (GA) as cross-linker, which was confirmed by photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopic studies. Results indicate that the activity of trypsin, immobilised onto chitosan modified nanocrystals, has improved upon cross-linking, which suggests that the immobilised trypsin has become more stable and active. This work highlights the prospects of potential applications of immobilised trypsin in therapeutic and diagnostic fields.

• 出版日期2013-5