Poly(Ethylene Glycol)-Serum Albumin Hydrogel as Matrix for Enzyme Immobilization: Biomedical Applications

Abstract

Poly(ethylene glycol)-albumin hydrogels were implanted in mice in subcutaneous position to study their biocompatibility. After one month of implantation, the fibrous capsule formed around the implant was thin and the inflammatory tissue was limited. Acid phosphatase (AP) was selected to evaluate the hydrogel as matrix for enzyme immobilization. AP-hydrogels were prepared using activated PEG (PEGa) of different molecular weights (M.W. 4,600 to 20,000) to evaluate the effect of the matrix composition on the activity of AP. The apparent Km of the immobilized AP was 16 to 20 times higher than the Km of the soluble enzyme. The apparent Km value decreases with the increase of the chain length of the PEGa used. This can be correlated to an increase in the hydrogel porosity. The operational stability of the AP was markedly improved after immobilization by 110 to 160 times according to the PEGa molecular weight involved. Also, asparaginase (ASNase) was immobilized in PEGa (M.W. 10,000)-albumin-hydrogel as a model for in vivo bioreactor. ASNase hydrogels were implanted in the peritoneal cavity of rats; 7 days later, 75% of the initial enzyme activity were retrieved.

Effect of Cd2+ and Hg2+ on the Activity of Na+/K+-ATPase and Mg2+-ATPase Adsorbed on Polystyrene Microtiter Plates

“…Adsorption harbors 10% fraction of initially applied amount of SPM, which is comparable with literature data concerning the protein adsorption on other support materials. It was reported that immobilization efficiency ranges from 0.1 to 40% and it depends on the chemical nature of the support and applied immobilization method (29,30). The results of the present study show that Na ϩ /K ϩ -ATPase and Mg 2ϩ -ATPase of aSPM retain about 70 -80% of native specific activity.…”

Immobilization of native and poly(ethylene glycol)‐treated (‘PEGylated’) bovine serum amine oxidase into a biocompatible hydrogel

“…They were used as drug‐controlled delivery devices [4] and as a matrix for enzyme immobilization [5,6]. These hydrogel slabs showed good biocompatibility [7,8] and were characterized by a high water content of about 95% (w/w) and good mechanical properties [9]. An enzyme can be immobilized into the matrix by dissolving it in the polymerization solution before the polymerization is started.…”

Photopolymerizable Hydrogels Made from Polymer‐Conjugated Albumin for Affinity‐Based Drug Delivery

“…There have been many attempts in the past to use PEG and albumin for a number of different applications. [13][14][15][16][17][18] Specifically, attempts to conjugate PEG to albumin were made for reducing bovine serum albumin immunogenicity, [19] for lipid factor delivery, [20] and as a model of protein delivery from PEG hydrogels. [21] Although PEG is most frequently used to conjugate biomolecules in order to achieve a decrease in immunogenicity and an increase in body-residence-time, [22] PEG's unique properties are also suited for drug delivery applications.…”