Degradation rate affords a dynamic cue to regulate stem cells beyond varied matrix stiffness

Area of Science:

• Biomaterials Science
• Stem Cell Biology
• Materials Chemistry

Background:

• Static cues like matrix stiffness influence stem cell differentiation.
• The impact of dynamic cues, such as hydrogel degradation rate and chemistry changes, on cell behavior remains less understood.
• Investigating dynamic cues is crucial for developing advanced biomaterials.

Purpose of the Study:

• To examine the effects of varying degradation rates on mesenchymal stem cell (MSC) adhesion and differentiation in vitro.
• To synthesize and characterize biodegradable poly(ethylene glycol) (PEG)-based hydrogels with tunable degradation.
• To explore how degradation rate, independent of stiffness, influences MSC fate.

Main Methods:

• Synthesized biodegradable PEG-based hydrogels using oligo(lactic acid) and acryloyl macromers.
• Fabricated peptide nanoarrays on hydrogels using block copolymer micelle nanolithography and transfer lithography.
• Controlled hydrogel degradation rates via accelerated pre-hydrolysis in acidic conditions.
• Cultured MSCs on hydrogels with varying stiffness and degradation rates, followed by adipogenic and osteogenic induction.

Main Results:

• Hydrogel degradation rate, modulated by pre-hydrolysis, significantly impacted MSC adhesion and differentiation.
• While adipogenic differentiation correlated with decreased matrix stiffness, osteogenic differentiation was unexpectedly enhanced on softer hydrogels.
• Higher degradation rates were identified as a key factor driving enhanced osteogenesis, particularly under co-induction conditions.

Conclusions:

• Hydrogel degradation rate acts as a critical dynamic cue influencing stem cell differentiation.
• This finding highlights the importance of considering degradation kinetics in the design of degradable biomaterials for tissue engineering.
• Dynamic cues offer novel strategies for controlling stem cell fate beyond static properties like stiffness.