Inclusion of Proteins into Polyelectrolyte Microparticles by Alternative Adsorption of Polyelectrolytes on Protein Aggregates

D. V. Volodkin^1*, N. G. Balabushevitch¹, G. B. Sukhorukov², and N. I. Larionova¹

¹School of Chemistry, Lomonosov Moscow State University, Moscow, 119992 Russia; fax: (095) 939-5417; E-mail: vdv1@pisem.net

²Max-Planck Institute of Colloids and Interfaces, Golm/Potsdam, 14476 Germany

^* To whom correspondence should be addressed.

Received June 12, 2002; Revision received September 2, 2002

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A new method of protein immobilization into polyelectrolyte microparticles by alternative adsorption of the oppositely charged polyelectrolytes on the aggregates obtained by salting out of protein is proposed. The model protein alpha-chymotrypsin (ChT) was included in the polyelectrolyte microparticles obtained by various number of polyelectrolyte adsorption steps (from 1 to 11). The main parameters of ChT inclusion into microparticles were calculated. Scanning electron and optical microscopy were used for characterization of morphology and determination of particle size which was from 1 to 10 µm in most cases. It was shown that the size and shape of protein-containing particles and protein aggregates used as a matrix were similar. Change in ChT enzymatic activity during entrapment into polyelectrolyte particles and activity of released protein were studied. The effect of pH on release of incorporated proteins was investigated; it was shown that change in pH and the number of polyelectrolyte adsorption steps allows protein release to be manipulated.

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KEY WORDS: polyelectrolyte microparticles, proteins, polyelectrolytes, poly(styrene sulfonate) sodium salt, poly(allylamine hydrochloride), alpha-chymotrypsin

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