“Off-the-shelf” thermoresponsive hydrogel design: tuning hydrogel properties by mixing precursor polymers with different lower-critical solution temperatures

Abstract

Mixing POEGMA precursor polymers with different LCSTs leads to linear changes in macroscopic gel properties (e.g. mechanics, swelling) but non-linear changes in properties dependent on gel microstructure (e.g. protein adsorption, cell adhesion).

Enhanced Mechanical Properties in Cellulose Nanocrystal–Poly(oligoethylene glycol methacrylate) Injectable Nanocomposite Hydrogels through Control of Physical and Chemical Cross-Linking

“…22,25 In particular, all mixed precursor polymer hydrogels exhibited significantly lower moduli than would be predicted based on a simple weighted average of the properties of the two constituent networks. Given the demonstrated higher affinity of PO 10 -based precursor polymers relative to PO 100 -based precursor polymers for CNC adsorption (Figure 6), we hypothesize that microphase domain separation of PO 10 and PO 100 precursor polymers leads to a correspondingly more heterogeneous incorporation of CNCs concentrated in the PO 10 -rich phase, thus reducing the capacity of CNCs to act as a reinforcing agent for the bulk hydrogel.…”

“…We have previously reported extensively on modular POEGMA hydrogels cross-linked via hydrazone bonds, formed by reactive extrusion of aldehyde and hydrazide-functionalized precursor polymers. 8,[22][23][24][25][26] Hydrogel properties including the lower critical solution temperature (LCST), cross-link density, swelling ratio, and cell adhesion can be modified by varying the ethylene oxide side chain length, 24 combining multiple precursor polymers, 22 or introducing hydrophobic domains into the precursor polymers. 26 However, the mechanical strength of these materials remains limited; more specifically, in the context of the highly protein and cell-repellent POEGMA hydrogels based on long oligo(ethylene glycol) side chains, even highly functionalized precursor polymers (30 mol % hydrazide or aldehyde-bearing repeat units) lead to hydrogels with only moderate mechanical strength (~1 kPa shear storage modulus).…”

Controlled degradation of low-fouling poly(oligo(ethylene glycol)methyl ether methacrylate) hydrogels

“…However, hydrogel degradation will not be required for drug efflux because P(EG) x MA gels with similar and higher crosslink densities have previously been demonstrated to release proteins for drug delivery applications. 44 Although, faster degradation rates will increase rates of drug release.…”

Polymers in medicine direction of development

“…Thermogels are formed during the physical conversion of sol-gel stimulated by changes in temperature [31][32][33]. Polymers that undergo thermogelation are based on natural polymers such as chitosan, hyaluronic acid, gelatin, and amylopectin [29,32], or synthetic ones such as amphiphilic block copolymers of poly(ethylene oxide) (PEG) and poly(propylene oxide) (PPG) [34], PEG-b-polyester copolymers where the polyester can be polylactide (PLA), polyglycolide (PGA), poly(lactide-co--glycolide) (PLGA) or polycaprolactone (PCL) [34][35][36], polymers based on N-isopropylacrylamide (PNIPAM) [37][38][39][40][41], and polymers based on oligo(ethylene glycol) methacrylates [42][43][44][45][46][47][48][49][50].…”