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Abstract

Introduction Immobilisation of biomaterials has been widely used in many fields, such as industry, biochemistry and immunology (Cheetham, 1985; Hermanson et al., 1992). This technology employs a large number of natural and artificial materials as matrices (Kennedy and Cabral, 1987). In our laboratory, we have proposed immobilisation procedures using dacron (Carneiro Leão et al., 1994), polyaniline (Nadruz et al., 1996) and glyptal (Jordão et al., 1996). Here, polyvinyl alcoholglutaraldehyde (PVA-glutaraldehyde) network is described for antigen and enzyme immobilisation. Previously, this material was used for the diagnosis of plague as a solid-phase in ELISA (Araujo et al., 1996) and also in laser induced fluorescence (Carvalho et al., 1996). Materials and methods Synthesis of PVA-glutaraldehyde beads Polyvinyl alcohol (2.0 g; Reagen ®) was dissolved in deionised water (20 mL) containing sodium dodecylsulfate (10 mg; Sigma) under heating and stirring. Glutaraldehyde (25%, w/v; 4.12 mL; Sigma) and H 2 SO 4 (0.3 M; 1 mL) were successively added to the dissolved PVA and then the solution was slowly poured into a beaker containing mineral oil/water mixture (45:45; v/v) with stirring. After about 15 min, PVA-glutaraldehyde beads were synthesised. In order to remove oil and sodium dodecylsulfate the beads were exhaustively washed with ethanol 95% v/v (500 mL) and deionised water (1 L). Synthesis of PVA-glutaraldehyde discs According to Araujo et al. (1996). Enzyme immobilisation ␣-Amylase (20 mL of 65 U/mg protein; Termamyl, Novo Nordisk, Paraná, Brazil) prepared in 50 mM citrate-phosphate buffer, pH 4.5, was incubated with PVA-glutaraldehyde beads (1 g) under stirring overnight at 4°C. After immobilisation, the water insoluble enzymatic derivative was washed with 1 M NaCl (100 mL) in buffer. Amyloglucosidase (20 mL of 6.5 U/mg protein; AMG, Novo Nordisk, Paraná, Brazil), prepared in 50 mM citrate-phosphate buffer, pH 6.5, was incubated with PVA-glutaraldehyde as described above. Xanthine oxidase (10 mL; Nutritional Biochemichals Corporation) prepared in 0.1 M phosphate buffer, pH 8.0, was incubated with PVAglutaraldehyde beads (0.6 g) under mild stirring overnight at 4°C. Then, the immobilised enzymatic derivative was exhaustively washed with deionised water and 1 M NaCl, successively. Afterwards, overnight incubation with 1 M glycine was carried out to inactivate free carbonyl groups and washings were carried out again.

Poly(vinyl alcohol)-Based Hydrogels Formed by “Click Chemistry”

“…The ester bond is, however, easily hydrolyzed, and chemical modification with ether linkages may be an alternative approach. PVA is reported to react with epoxides and alkyl halides according to the Williamson ether synthesis. , The carbonyl group in aldehydes can be coupled to PVA via acetal rings. , However, harsh conditions normally associated with either ether or acetal linkage formation cannot be applied for appending of sensitive functionalities. Although hydroxyl groups in PVA show little reactivity at low temperatures, we have been interested in chemical modification of PVA hydroxyl groups under mild conditions, which would permit efficient incorporation of a broad range of chemical functionalities.…”

“…Hydrogels was thus formed by chemoselective 1,3-cycloaddition between alkynyl and azido functional groups of PVA components with the multiple formation of triazole cross-links (Figure A). Chemically cross-linked PVA hydrogels have been mostly prepared using bifunctional cross-linking agents, such as glutaraldehyde and hexamethylene diisocyanate, which react directly with PVAs hydroxyl groups. , As was mentioned above, cross-linking with low-molecular-weight toxic reagents is not practicable for in-situ hydrogel formation. Photo-cross-linking of PVA functionalized with the photo-cross-linkable groups such as acrylate ,,, or furan-based photosensitive chromophores 39 was employed recently in order to preserve the biocompatibility of PVA-based chemical hydrogels.…”

Immobilization of Anti-Galectin-3 onto Polysiloxane–Polyvinyl Alcohol Disks for Tumor Prostatic Diseases Diagnosis

“…In our laboratories, several supports have been proposed for biomolecules immobilization: Dacron [42,43]; ferromagnetic Dacron [44,45]; polyvinyl alcohol-glutaraldehyde network [46][47][48]; polyaniline-Dacron composite [49]; plasticized filter paper with polyvinyl alcohol-glutaraldehyde [50].…”

Immobilization of β-galactosidase from Kluyveromyces lactis onto a polysiloxane–polyvinyl alcohol magnetic (mPOS–PVA) composite for lactose hydrolysis

“…Afterwards, the beads are smashed to increase the immobilization surface (second step) and the particles are co-precipitated with Fe 2+ and Fe 3+ (third step) to provide them with magnetic properties in order to facilitate support recovery from the reaction medium. Finally, glutaraldehyde is attached to the polyvinyl alcohol vicinal hydroxyl groups under acid catalysis [23], and allowing the b-galactosidase immobilization by acting as a chemical spacer-arm. The linkage of the enzyme to the polyvinyl alcohol-glutaraldehyde is schematically represented in Fig.…”