Bioactivity of permselective PVA hydrogels with mixed ECM analogues

Abstract

The presentation of multiple biological cues, which simulate the natural in vivo cell environment within artificial implants, has recently been identified as crucial for achieving complex cellular functions. The incorporation of two or more biological cues within a largely synthetic network can provide a simplified model of multifunctional ECM presentation to encapsulated cells. Therefore, the aim of this study was to examine the effects of simultaneously and covalently incorporating two dissimilar biological molecules, heparin and gelatin, within a PVA hydrogel. PVA was functionalized with 7 and 20 methacrylate functional groups per chain (FG/c) to tailor the permselectivity of UV photopolymerized hydrogels. Both heparin and gelatin were covalently incorporated into PVA at an equal ratio resulting in a final PVA:heparin:gelatin composition of 19:0.5:0.5. The combination of both heparin and gelatin within a PVA network has proven to be stable over time without compromising the PVA base characteristics including its permselectivity to different proteins. Most importantly, this combination of ECM analogues supplemented PVA with the dual functionalities of promoting cellular adhesion and sequestering growth factors essential for cellular proliferation. Multi-functional PVA hydrogels with synthetically controlled network characteristics and permselectivity show potential in various biomedical applications including artificial cell implants.

Photopolymerized Porous Hydrogels

“…This photoinitiator was shown to be much less cytotoxic than DMPA , for a similar reactivity with (meth)­acrylate moieties. It has been widely used for synthesizing porous photopolymerized hydrogels for biomedical purposes. − However, its drawbacks lie in its low molar absorption coefficient and the need of UV light that may be detrimental to living cells …”

“…Generally, the grafting of polymerizable groups is made by reaction of hydroxyl or amine functions borne by the polymeric precursor with (meth)­acryloyl chloride, (meth)­acrylic anhydride, (meth)­acrylic acid (in the presence of EDC and NHS), or glycidyl methacrylate. Many researchers have also associated two or more polymers to form a conetwork or interpenetrated polymer networks (IPNs). ,,,,,,,,,,,− …”

“…This approach was used by many authors for determining the intrinsic mesh size (without porogen) of photopolymerized hydrogels ,,,− ,,,,,− or the size of pores created upon degradation of the hydrogels. ,,, Pore sizes ranging from a few nanometers to 100s of nanometers were determined by this technique.…”

Electroresponsive Hydrogels for Therapeutic Applications in the Brain

“…[140] In certain cases, the hydrophilic and anti-fouling properties of electroconductive hydrogels prevent cell attachments, [141] which can be mitigated by functionalizing hydrogels with molecules such as gelatin and sericin to promote neuronal attachment and growth. [142] As such, hydrogels can be modified post-fabrication with chemical functionalization [143] and surface modifications to strengthen bonding and covalent interactions between hydrogels and neuroprosthetic devices. [34] These modifications can direct the responses of hydrogels to electric fields and guide their interactions with surrounding cells.…”

Reconstruction Strategies of the Ureter and Urinary Diversion Using Tissue Engineering Approaches

“…The ultra violet (UV) photopolymerized PVA hydrogels were prepared via methacrylated functionalization, and the effects of incorporation of heparin and GEL within a PVA hydrogel were examined. 167 Chen et al advanced the novel double network PEG/COL, whose mechanical strength could be modified by changing the rigidity, molecular weight, and crosslinking density of the two components. Results indicated that the incorporation of COL significantly enhanced the strength and toughness of hydrogels.…”