Crosslinked Hyaluronan Hydrogel ECM
Thiol-ene crosslinked methacrylated hyaluronic acid hydrogel with storage modulus G′ ≈ 1.2 kPa, controlled enzymatic degradation, and tunable RGD presentation.
The primary extracellular matrix mimic is a methacrylated hyaluronic acid (MeHA) hydrogel crosslinked through visible-light thiol-ene chemistry with a 4-arm PEG-dithiol (lithium phenyl-2,4,6-trimethylbenzoylphosphinate photoinitiator, 405 nm, 5 mW/cm², 60 s). This avoids the cytotoxicity of UV/Irgacure 2959 systems while preserving cell viability >95 % at encapsulation.
Bulk mechanical tuning targets G′ of 1.2 kPa (soft dermal tissue) and a loss tangent below 0.10 at 1 Hz. RGD adhesion peptide is conjugated at 1.5 mM via thiol-Michael addition for integrin engagement. Hyaluronidase-mediated degradation half-life is held at ≈ 14 days in vitro to coincide with the scaffold ingrowth window.
| Parameter | Value | Unit | Tolerance / Note |
|---|---|---|---|
| Base polymer | Methacrylated HA | Methacrylation DS ≈ 25 % | |
| Crosslinker | 4-arm PEG-dithiol | ||
| Photoinitiator | LAP 0.05 % w/v | ||
| Cure | 405 nm / 5 mW/cm² / 60 s | ||
| Storage modulus G′ | 1.2 | kPa | 1 Hz, 37 °C |
| Loss tangent (tan δ) | <0.10 | 1 Hz | |
| RGD density | 1.5 | mM | |
| Degradation t½ | ~14 | days | Hyaluronidase mediated |
| Cell viability post-cure | >95 | % |