The Impact of the L. Extract, Starch Solution and the Photoinitiator on Physiochemical Properties of Acrylic Hydrogels.

L. extract is well-known for its therapeutic properties; thus, it shows potential to be used to modify materials designed for biomedical purposes. In this paper, acrylic hydrogels modified with this extract were prepared. The other modifier was starch introduced into the hydrogel matrix in two forms: room-temperature solution and elevated-temperature solution. Such hydrogels were synthesized via UV radiation, while two types of photoinitiator were used: 2-hydroxy-2-methylpropiophenone or phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide. The main task of performed research was to verify the impact of particular modifiers and photoinitiator on physicochemical properties of hydrogels. Studies involved determining their swelling ability, elasticity, chemical structure via FTIR spectroscopy and surface morphology via the SEM technique. Incubation of hydrogels in simulated physiological liquids, studies on the release of chamomile extract from their matrix and their biological analysis via MTT assay were also performed. It was demonstrated that all investigated variables affected the physicochemical properties of hydrogels. The modification of hydrogels with chamomile extract reduced their absorbency, decreased their thermal stability and increased the cell viability incubated with this material by 15%. Next, hydrogels obtained by using phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide as a photoinitiator showed lower absorbency, more compact structure, better stability in SBF and a more effective release of chamomile extract compared to the materials prepared by using 2-hydroxy-2-methylpropiophenone. It was proved that, by applying adequate reagents, including both photoinitiator and modifiers, it is possible to obtain hydrogels with variable properties that will positively affect their application potential.