Fabrication of a biodegradable polysaccharide hydrogel with riboflavin, vitamin B2, as a photo‐initiator and L‐arginine as coinitiator upon UV irradiation

Abstract

The objective of this study is to develop a completely natural material based photo-initiation system for fabricating biologically compatible hydrogels, that is, free of any synthetic materials like conventional synthetic photo-initiators. The resulting biodegradable hydrogels would be completely free of conventional toxic synthetic substances. Dextran-based precursor was used as a model system for this study. The natural material based photo-initiation system used riboflavin (vitamin B2) as photo-initiator and L-arginine as a coinitiator. Dextran-methacrylate precursor was prepared to introduce photosensitive unsaturated moieties into dextran for subsequent photo-induced gel formation. Riboflavin alone could not initiate the photo-crosslinking reaction of the dextran methacrylate solution upon UV irradiation. L-arginine, which can act as an electron donor in the photo-initiation process, was used as a coinitiator. The optimum gel formulation conditions in terms of the concentrations of riboflavin and L-arginine as well as different pH media were extensively investigated. The dextran-methacrylate hydrogels were formed well and fast at low riboflavin concentration range (0.2-1 wt %), and L-arginine promoted the photo-initiation at all concentrations. The gelation was promoted most in the neutral pH and the least in the alkaline pH. The turbidity of the dextran-methacrylate hydrogel precursor solution affected the polymerization because UV penetration was significantly hindered as the opacity of the solution increased. The swelling property and structural visualization of the prepared hydrogels were also investigated.

Comparison of visible and UVA phototoxicity in neural culture systems micropatterned with digital projection photolithography

“…A 50% MeDex solution was tested with variable concentrations of RF, l ‐arginine (Arg), and tetramethylethylenediamine (TEMED). The composition was adjusted until a consistent gel formed at three time points: 30, 60 and 90 s. The final composition was MeDex 50% (w/v), Arg 0.1% of MeDex (w/w), RF 0.001% of MeDex (w/w), and TEMED 0.2% of the final solution (v/v) …”

“…Despite broad reaching applications, a limitation of using photosensitive hydrogels is the possible harmful effect of irradiation on the cells during encapsulation . The two principal wavelength spectra implemented for this purpose are UVA (315–400 nm) and visible light (400–700 nm).…”

“…To study the influence of these wavelengths on neuronal behavior, including cytotoxicity and cellular apoptosis as a result of photoencapsulation, we utilized 3D hydrogels that incorporate ‐(−) Riboflavin (RF), a photoinitiator that has similar light absorption quantities in UVA and visible region . Functionalized dextran has been shown to have the potential of forming a hydrogel network upon addition of RF as a photoinitiator . This design allows a unique platform to study the effect of visible and UVA light on cytotoxicity due to irradiation.…”

Biodegradable Microparticles for Simultaneous Detection of Counterfeit and Deteriorated Edible Products

“…Riboflavin requires an electron donor to work as a photoinitiator. l ‐arginine is a natural amino acid, which has been successfully implemented as an electron donor for riboflavin . Using riboflavin and arginine allowed us to avoid traditional, possibly harmful, phenone photoinitiators, which have been used up to now with SFL.…”

“…l ‐arginine is a natural amino acid, which has been successfully implemented as an electron donor for riboflavin . Using riboflavin and arginine allowed us to avoid traditional, possibly harmful, phenone photoinitiators, which have been used up to now with SFL. Furthermore, riboflavin is photosensitive in the visible part of the spectrum, hence we could use visible light (400–490 nm) for crosslinking.…”