  Implantable hydrogels should ideally possess mechanical properties matched to
the surrounding tissues to enable adequate mechanical function while
regeneration occurs. This can be challenging, especially when degradable
systems with high water content and hydrolysable chemical bonds are required in
anatomical sites under constant mechanical stimulation, e.g. a foot ulcer
cavity. In these circumstances, the design of hydrogel composites is a
promising strategy to provide controlled structural features and macroscopic
properties over time. To explore this strategy, the synthesis of a new
photocurable elastomeric polymer, poly(glycerol-co-sebacic acid-co-lactic
acid-co-polyethylene glycol) acrylate (PGSLPA), is investigated, along with its
processing into UV-cured hydrogels, electrospun nonwovens and fibre-reinforced
variants, without the need for a high temperature curing step or use of
hazardous solvents. The mechanical properties of bioresorbable PGSLPA hydrogels
were studied with and without electrospun nonwoven reinforcement and with
varied layered configurations, aiming to determine the effects of
microstructure on bulk compressive strength and elasticity. The nonwoven
reinforced PGSLPA hydrogels exhibited a 60 % increase in compressive strength
and an 80 % increase in elastic moduli compared to fibre-free PGSLPA samples.
Mechanical properties of the fibre-reinforced hydrogels could also be modulated
by altering the layering arrangement of the nonwoven and hydrogel phase. The
nanofibre reinforced PGSLPA hydrogels also exhibited good elastic recovery, as
evidenced by hysteresis in compression fatigue stress-strain evaluations
showing a return to original dimensions.
