Bioartificial Polymeric Material: Poly(Ethylene Glycol) Crosslinked with Albumin. II: Mechanical and Thermal Properties

Abstract

A family of hydrogels based on the crosslinking of bovine serum albumin (BSA) and activated poly(ethylene glycol) (PEG), were characterized. The swelling process was found to be dependent on the molecular weight of the PEG used and on the OH/NH2 molar ratio of the reagents. These hydrogels performed a volume expansion from 266 to 554% when PEG with molecular weights from 3,350 to 20,000 were used. The volume expansion was greater when the OH/NH2 molar ratio increased. Some anisotropy occurred during swelling since thinner devices swelled more than thicker ones, due to the difference of constraints in the hydrogels structure. Mechanical studies showed that these hydrogels were highly deformable and presented good elastic behavior since they broke only after 80% deformation. At this point, they needed a compression force ranging from 165 to 456 g/cm2 to break. The differentiation of two kinds of water in these highly swollen hydrogels was performed using DSC studies at low temperature. Free water (i.e., bulk water) was found to be the predominant form which filled the network, .and bound water (i.e., water engaged in interactions with PEG) tended to form a trihydrate complex (three molecules of water per ethylene oxide repeated unit). Three forms of water with different evaporating rates were detected by DSC studies at high temperature. This other form of water may be important for maintaining the hydrogen's form.

Mechanical and microstructural properties of hybrid poly(ethylene glycol)–soy protein hydrogels for wound dressing applications

“…The details of the hydrogel synthesis have been published elsewhere. 2,[18][19][20][21] In brief, hydrogel formation is achieved via a condensation reaction between the amino groups of protein and carbonate-activated PEG with subsequent release of p-nitrophenol molecules. As a result of this reaction, stable urethane linkages between a biopolymer and PEG are formed.…”

“…2 The protein component of the hydrogel contributes to the ''tissue-like'' properties, whereas the bioinert polymer chains of PEG are responsible for the hydrophilicity of the material. This hydrogel contains up to 96% of water 2,18,19 and is presently used as a moist wound dressing and transdermal drug delivery device. Recent studies demonstrated that the PEG-protein hydrogel is inflammatory inert and accelerates wound closure in vivo.…”

Phase Transition Behavior, Protein Adsorption, and Cell Adhesion Resistance of Poly(ethylene glycol) Cross-Linked Microgel Particles

“…Hydrogels, three-dimensional networks of hydrophilic polymer chains, have found many applications in biomedicine and biotechnology due to their high water content, soft tissue-like consistency, and, thus, potential biocompatibility. − They have been used in such areas as tissue engineering, artificial organs, and drug release devices. , Poly( N -alkyl acrylamides), pNIPAm, in particular, have been extensively studied with respect to their thermoresponsivity. , These systems undergo a reversible volume phase transition (VPT) at a lower critical solution temperature (LCST) where the hydrogel hydrophobically collapses upon itself, thereby expelling water in an entropically favored fashion. Isopropyl groups in the pNIPAm side chains play an important role in this temperature-dependent phase separation above the LCST. , The temperature at which this coil-to-globule transition occurs is approximately 31 °C, , with this temperature being dependent on the identity of the N -alkyl group.…”

“…Hydrogels, three-dimensional networks of hydrophilic polymer chains, have found many applications in biomedicine and biotechnology due to their high water content, soft tissue-like consistency, and, thus, potential biocompatibility. [1][2][3][4][5][6][7] They have been used in such areas as tissue engineering, artificial organs, and drug release devices. 2,7 Poly(N-alkyl acrylamides), pNIPAm, in particular, have been extensively studied with respect to their thermoresponsivity.…”

In situ photopolymerization of PEGDA‐protein hydrogels on nanotube surfaces

“…The shape of this peak also shows the presence of a shoulder, that may be because of the slow rate of evaporation of residual bound water that may have been present in the sample. 96 Thus overall, the materials obtained are partly crystalline. A high degree of crystallinity is not displayed most likely due to the cross-links formed with protein bound nanotubes.…”