Engineering poly(dehydroalanine)-based gels via droplet-based microfluidics: from bulk to microspheres.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Biomedical applications require reversible molecular loading and release.
• Poly(dehydroalanine) is a promising polyzwitterion for switchable adsorption due to its pH-dependent charges.
• Integrating poly(dehydroalanine) into gel networks enhances its potential for controlled guest molecule interactions.

Purpose of the Study:

• To fabricate poly(dehydroalanine)-derived microgels of varying sizes using microfluidics.
• To evaluate the properties and biomedical applicability of these microgels.
• To investigate the influence of microgel size and crosslinking density on guest molecule adsorption.

Main Methods:

• Remodeling bulk gelation protocols for droplet-based microfluidic synthesis.
• Fabricating microgels of approximately 30 μm and 200 μm sizes.
• Analyzing microgel composition, permeability, and softness, and assessing pH- and ionic strength-sensitivity.
• Demonstrating pH-regulated uptake and release of fluorescent dyes and adsorption of antimicrobial peptide LL-37.
• Validating microgel biocompatibility through cell tests.

Main Results:

• Microfluidic synthesis yielded poly(dehydroalanine) microgels of distinct sizes (30 μm and 200 μm).
• Microgel properties (composition, permeability, softness) were tunable via crosslinker choice and density.
• The microgels exhibited high hydrophilicity and sensitivity to pH and ionic strength.
• Successful pH-regulated loading and release of model dyes and adsorption of LL-37 peptide were demonstrated.
• Microgel size and crosslinking density impacted peptide accommodation, and the microgels showed good biocompatibility.

Conclusions:

• Poly(dehydroalanine)-derived microgels are effectively fabricated using microfluidics for biomedical applications.
• These microgels possess tunable properties and demonstrate controlled, pH-responsive molecular adsorption and release.
• The findings support the potential of these zwitterionic microgels in areas like drug delivery and tissue engineering.