Poly(vinyl alcohol)-heparin biosynthetic microspheres produced by microfluidics and ultraviolet photopolymerisation

Abstract

Biosynthetic microspheres have the potential to address some of the limitations in cell microencapsulation; however, the generation of biosynthetic hydrogel microspheres has not been investigated or applied to cell encapsulation. Droplet microfluidics has the potential to produce more uniform microspheres under conditions compatible with cell encapsulation. Therefore, the aim of this study was to understand the effect of process parameters on biosynthetic microsphere formation, size, and morphology with a co-flow microfluidic method. Poly(vinyl alcohol) (PVA), a synthetic hydrogel and heparin, a glycosaminoglycan were chosen as the hydrogels for this study. A capillary-based microfluidic droplet generation device was used, and by varying the flow rates of both the polymer and oil phases, the viscosity of the continuous oil phase, and the interfacial surface tension, monodisperse spheres were produced from $200 to 800 lm. The size and morphology were unaffected by the addition of heparin. The modulus of spheres was 397 and 335 kPa for PVA and PVA/heparin, respectively, and this was not different from the bulk gel modulus (312 and 365 for PVA and PVA/heparin, respectively). Mammalian cells encapsulated in the spheres had over 90% viability after 24 h in both PVA and PVA/heparin microspheres. After 28 days, viability was still over 90% for PVA-heparin spheres and was significantly higher than in PVA only spheres. The use of biosynthetic hydrogels with microfluidic and UV polymerisation methods offers an improved approach to long-term cell encapsulation. V C 2013 AIP Publishing LLC. [http://dx

Chronic Wound Dressings Based on Collagen-Mimetic Proteins

“…32 Fluidic methods have shown improved fabrication processes with the potential to photopolymerize hydrogel microspheres. 33 In this study, integrin affinity and cell adhesion to Scl2 GFPGER , eCol GFPGER , or an animal-derived collagen control were determined as an initial assessment of potential for wound care applications. Degradation of the hydrogels as a function of composition was investigated to identify promising compositions that permit reduced dressing changes.…”

Biopolymer Microparticles Prepared by Microfluidics for Biomedical Applications

“…[116] Composite microspheres of heparin and poly(vinyl alcohol) (PVA) have been prepared for cell encapsulation by combining a microfluidic approach with UV photo-crosslinking. [117] The fibroblast-laden heparin-PVA microspheres exhibited a high viability of encapsulated cells (>90%). In addition, composite microspheres composed of heparin and polyethylene glycol (PEG) with growth factors such as Nodal and fibroblast growth factor-2 (FGF-2) were exploited to direct pluripotent ESCs toward endoderm-specific differentiation.…”

“…Composite microspheres of heparin and poly(vinyl alcohol) (PVA) have been prepared for cell encapsulation by combining a microfluidic approach with UV photo‐crosslinking . The fibroblast‐laden heparin‐PVA microspheres exhibited a high viability of encapsulated cells (>90%).…”

On-Chip Facile Preparation of Monodisperse Resorcinol Formaldehyde (RF) Resin Microspheres

“…Many efforts have contributed to producing uniform resol resin microspheres, such as hydrothermal synthesis, emulsion polymerization, and spray drying [ 5 , 6 , 7 ]. Notably, the droplet-based microfluidic technique is useful for the fabrication of microparticles, including hydrogel-based microparticles, plastic-based microparticles, and certain microcapsules [ 8 , 9 , 10 , 11 ]. Compared with conventional methods, the droplet-based microfluidic technique can precisely control the entire material fabrication processes, and the microscale size benefits the mass and heat transfer rate [ 11 , 12 , 13 , 14 ].…”