Design of electrohydrodynamic sprayed polyethylene glycol hydrogel microspheres for cell encapsulation

Area of Science:

• Biofabrication and biomaterials engineering.
• Cell microencapsulation technologies.

Background:

• Electrohydrodynamic spraying (EHS) is popular for cell microencapsulation using natural polymers like alginate and chitosan.
• There is a need to expand EHS applications beyond natural polymers for broader biofabrication.
• Previous work demonstrated polyethylene glycol (PEG) microsphere fabrication via EHS.

Purpose of the Study:

• To utilize EHS principles for fabricating cell-laden PEG hydrogel microspheres.
• To investigate critical EHS parameters for controlled size and high cell viability.
• To assess the compatibility of EHS with different cell types and densities.

Main Methods:

• Fabrication of PEG hydrogel microspheres via covalent crosslinking of multiarm PEG acrylate and dithiol crosslinkers using Michael-type addition.
• Optimization of EHS parameters: applied voltage, inner needle diameter, and flow rate.
• Encapsulation efficiency, cell viability, cell dispersion, and cell culture studies.

Main Results:

• Achieved controlled PEG hydrogel microsphere diameters (70-300 μm) with low polydispersity (6-23%).
• Demonstrated high encapsulation efficiency (≥90%) and compatibility with cell densities of 10^6-10^9 cells/mL.
• Identified optimal voltage (<5 kV) to prevent cell aggregation and utilized Arg-Gly-Asp-Ser (RGDS) peptide tethering to improve cell dispersion in synthetic PEG.

Conclusions:

• The developed EHS technique enables the fabrication of cell-laden PEG hydrogel microspheres with controlled sizes and high cell viability.
• The method overcomes limitations of synthetic polymers by enabling RGDS peptide tethering for improved cell dispersion.
• This technique holds potential for applications in cell delivery and organoid cultures.