New approaches of invertase immobilisation on functionalised support-nanoparticles and films

Mihaela I. Mihalache 1Eugenia D. Teodor 1Cristian Petcu 3Gabriel-Lucian Radu 1,4Simona Carmen F. Litescu 1,2

1. National Institute for Biological Sciences, Centre of Bioanalysis, 296 Splaiul Independetei, Bucharest 06003, Romania
2. University of Bucharest, Faculty of Chemistry, Panduri 90, Bucharest, Romania
3. National Institute for Chemical and Petrochemical Research, Bucharest 060021, Romania
4. University Politehnica of Bucharest, Polizu 1-7, Bucharest, Romania


The experiments were focused on two directions: immobilisation of invertase on new supports based on chitosan and hyaluronic acid ionically cross-linked and on magnetic nanoparticles covered with various polymers.

Biopolymeric films were obtained by mixing different ratios of 2% (w/v) chitosan and 1% (w/v) hyaluronate solutions. Chitosan/hyaluronic acid films were cross-linked with sodium citrate by soaking chitosan/hyaluronic acid films into a sodium citrate solutions (2.5, 5%, w/v). Immobilisation of the enzime on the film surface was made through immersion. The ultrastructure of carried out films (chitosan, chitosan/hyaluronic acid and invertase immobilised on chitosan/hyaluronic acid film) were exmined using Confocal Scanning Laser Microscopy.

Magnetic nanoparticles were synthetized by thermal co-precipitation of ferric and ferrous chloride. In order to improve biocompatibility, magnetic carriers were encapsulated using polyvinyl alcohol, polyethylene glycol, polyvinyl acetate and polyacrilic acid as sheel materials. Enzyme was immobilized on the functionalized surface. Transmision Electron Microscopy and Scanning Electron Microscopy were used to characterize the particles, having a size between 18 nm and 580 nm. Fourier Transformed Infrared Spectroscopy was used to confirm the structure of functionalized particles and also the enzyme binding, via monitoring the changes in shape, intensity and wavelength shift (1715.5 - 1732 cm-1) of the - COOH group of polymers.

The study indicates that the stability and activity of enzyme were enhanced via magnetic nanoparticles and films binding.


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Presentation: Short communication at SMCBS'2005 Workshop, by Eugenia D. Teodor
See On-line Journal of SMCBS'2005 Workshop

Submitted: 2005-07-28 12:43
Revised:   2009-06-07 00:44