Redox‐Responsive Degradable PEG Cryogels as Potential Cell Scaffolds in Tissue Engineering

Abstract

A Michael addition strategy involving the reaction between a maleimide double bond and amine group has been investigated for the synthesis of cryogels at subzero temperature (-8 o C).Low molecular weight PEG-based building blocks with amine end groups on one hand and disulfide containing building blocks with maleimide end groups on the other hand are combined to synthesize redox-responsive PEG cryogels. The cryogels exhibit an interconnected macroporous morphology, a high compressive modulus (> 100 kPa) and gelation yields of around 95%. While the cryogels are stable under physiological conditions, complete dissolution of the cryogels into water soluble products is obtained in the presence of a reducing agent (glutathione) in the medium. Cell seeding experiments and toxicologic analysis demonstrate their potential as scaffolds in tissue engineering.-2 -

Pore orientation mediated control of mechanical behavior of scaffolds and its application in cartilage-mimetic scaffold design

“…Equilibrium swelling ratio was calculated using the following formula: Equilibrium swelling ratio¼[(Wet weightÀDry weight)/(Dry weight)]. Porosity of scaffolds was determined using two methods, namely liquid displacement and water squeezing method as reported previously (Amrita et al, 2015;Dispinar et al, 2012). Detailed protocols for these methods have been described in the supplementary methods.…”

Facile approach to prepare pH and redox-responsive nanogels via Diels-Alder click reaction

“…Other solvents and chemicals of analytical grade were used as received. Dithiobismaleimidoethane (DTME) was synthesized as described in the previous work [29]. The crude compound was purified via column chromatography (ethyl acetate: hexane = 1:1).…”

A Brief History of Polymeric Cryogels

“…In any case, the basic principle is that one of the precursors must be at least trifunctional or higher in order to ensure the branched 3D character of the forming polymer and its crosslinking. One recent example realizing this principle is the polycondensation-type cryogel prepared via the reaction of threearm amino-terminated oligo(ethylene glycol) star polymers with dithio-bis (maleimido)ethane in the medium of non-deeply frozen dioxane at À8 C [174]. Here, a 3D polymeric network forms as a result of the Michael addition of the primary amino groups to the double bonds of maleimide residues.…”