Amphipathic Substrates Based on Crosslinker-Free Poly(ε-Caprolactone):Poly(2-Hydroxyethyl Methacrylate) Semi-Interpenetrated Networks Promote Serum Protein Adsorption

Abstract

A simple procedure has been developed to synthesize uncrosslinked soluble poly(hydroxyethyl methacrylate) (PHEMA) gels, ready for use in a subsequent fabrication stage. The presence of 75 wt % methanol (MetOH) or dimethylformamide (DMF) impedes lateral hydroxyl–hydroxyl hydrogen bonds between PHEMA macromers to form during their solution polymerization at 60 °C, up to 24 h. These gels remain soluble when properly stored in closed containers under cold conditions and, when needed, yield by solvent evaporation spontaneous physically-crosslinked PHEMA adapted to the mould used. Moreover, this two-step procedure allows obtaining multicomponent systems where a stable and water-affine PHEMA network would be of interest. In particular, amphiphilic polycaprolactone (PCL):PHEMA semi-interpenetrated (sIPN) substrates have been developed, from quaternary metastable solutions in chloroform (CHCl3):MetOH 3:1 wt. and PCL ranging from 50 to 90 wt % in the polymer fraction (thus determining the composition of the solution). The coexistence of these countered molecules, uniformly distributed at the nanoscale, has proven to enhance the number and interactions of serum protein adsorbed from the acellular medium as compared to the homopolymers, the sIPN containing 80 wt % PCL showing an outstanding development. In accordance to the quaternary diagram presented, this protocol can be adapted for the development of polymer substrates, coatings or scaffolds for biomedical applications, not relying upon phase separation, such as the electrospun mats here proposed herein (12 wt % polymer solutions were used for this purpose, with PCL ranging from 50% to 100% in the polymer fraction).

Toughened Hydrogels for 3D Printing of Soft Auxetic Structures

“…As shown in Figure 5a, although there is no cross-linking agent in 30H-NOX-3D, there are a physical cross-linking based on hydrogen bonds from the terminal hydroxyl groups of pHEMA and a subsequent entanglement between pHEMA polymer chains. [34] These polymer chains entanglements can act as mobile cross-links for energy dissipation, [35] which contribute to the high fracture strain of 30H-NOX-3D hydrogel. Furthermore, the hydrogen bonds between the hydroxyl groups on pHEMA polymer chains are considered as the weakest intermolecular interactions, [35][36] therefore, a low tensile strength and modulus are found for the 30H-NOX-3D hydrogel.…”

Preparation of Superabsorbent Beads via Superfast Photopolymerization and Their Characterization

“…For example, polymer B's peak water absorbance was 28–29 at room temperature, while it was only 22–23 at 40 °C after 72 h. It was reported that poly(2‐hydroxyethyl methacrylate) (PHEMA) had the hydrophobicity of its backbone. [ 27 ] Prins and co‐workers observed that the PHEMA gel's swelling in water decreased from 30 to 50 °C. [ 27 ] Jhon and co‐workers reported the decreased permeability of electrolytes in uncross‐linked PHEMA membrane from 5 to 15 °C due to decreased water content in the membrane.…”

“…[ 27 ] Prins and co‐workers observed that the PHEMA gel's swelling in water decreased from 30 to 50 °C. [ 27 ] Jhon and co‐workers reported the decreased permeability of electrolytes in uncross‐linked PHEMA membrane from 5 to 15 °C due to decreased water content in the membrane. [ 28 ] Water absorbance results from this study suggest that the beads’ hydrophobicity from HEMA units’ backbone in the copolymers increased from room temperature to 40 °C.…”