Photoimmobilization of organophosphorus hydrolase within a PEG-based hydrogel

Abstract

Organophosphorous hydrolase (OPH) was physically and covalently immobilized within photosensitive polyethylene glycol (PEG)‐based hydrogels. The hydroxyl ends of branched polyethylene glycol (b‐PEG, four arms, MW = 20,000) were modified with cinnamylidene acetate groups to give water‐soluble, photosensitive PEG macromers (b‐PEG‐CA). The b‐PEG‐CA macromers underwent photocrosslinking reaction and formed gels upon UV irradiation (>300 nm) in the presence of erythrosin B. Native OPH was pegylated with cinnamylidene‐terminated PEG chains (MW = 3400) to be covalently linked with the b‐PEG‐CA macromers during photogelation. The effect of pegylation on the stability of the enzyme was determined. Furthermore, the effect of enzyme concentration, wavelength of irradiation, and photosensitizer on the stability of the entrapped enzyme was also investigated. The pegylated OPH was more stable than the native enzyme, and the OPH‐containing gels exhibited superior stability than the soluble enzyme preparations. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 65: 579–588, 1999.

Photoreversible Chain Extension of Poly(ethylene glycol)

“…[29][30][31][32][33] The crosslinked hydrogels were synthesized via a reaction between either cinnamylidene acetyl chloride or 9-anthracenecarbonyl chloride and the terminal hydroxyl units of a 4-armed PEG (MW ¼ 20 000 g Á mol À1 ) star-shaped polymer. Andreopoulos and coworkers were able to reversibly control the degree of swelling (between 10 and 20%) of the hydrogels in water.…”

Environmentally responsive injectable materials

“…The formed shapes are long-lasting and can be transformed back into their original shape only by being exposed to ambient temperature and by altering the wavelength of UV light (Lendlein et al 2005). Andreopoulos et al (1999), in a different study, immobilized the enzyme, organophosphorous hydrolase, in a PEG-cinnamylidene acetate hydrogel. They observed that the hydrogel, with an irradiation of 30 and 45 minutes at 300 nm, provoked the crosslinking of the gel and little enzyme escape was detected.…”

Critical factors in the design of growth factor releasing scaffolds for cartilage tissue engineering

“…In these materials, the double bonds available along the PPF backbone are crosslinked through the use of a vinyl monomer, N -vinyl pyrrolidinone, and an initiator, benzoyl peroxide [98][99][100] , with minimal temperature rise. However, the incorporation of proteins and growth factors in such in situ polymerizable hydrogels might be hampered by the exposure to ultraviolet light and crosslinking agents, which can induce protein denaturation or aggregation and decrease the activity of encapsulated proteins [101] .…”