Solvent‐Free Fabrication of polyHIPE Microspheres for Controlled Release of Growth Factors

Abstract

The growth factor bone morphogenetic protein 2 (BMP-2) is utilized in surgical procedures to improve bone regeneration; however, current treatments deliver BMP-2 at amounts greater than 100,000 fold of physiological levels, which increases treatment costs and risk of side effects. Drug-eluting microcarriers developed to improve these therapies have faced significant commercialization challenges including particle size distributions, solvent removal, low encapsulation efficiency, and bioactivity loss. In this study, a solvent-free method is presented for fabrication of uniform polyHIPE microspheres for controlled growth factor release. Emulsion templating principles and fluid dynamics were used to fabricate uniform particles with tunable particle size (200-800 μm) and pore size (10-30 μm). The ability to independently tune particle and pore size is expected to provide excellent control of release kinetics. Overall, this solvent-free method for making porous microspheres displays strong promise for the controlled release of BMP-2 and other growth factors.

Basic Principles of Emulsion Templating and Its Use as an Emerging Manufacturing Method of Tissue Engineering Scaffolds

“…Moglia et al developed bone morphogenetic protein 2 (BMP-2) releasing solvent-free ethylene glycol dimethacrylate PolyHIPE microspheres using w/o/w double emulsion system (Moglia et al, 2014a). They reported that while the encapsulation efficiency of their system was up to 73%, but this efficiency reduced to as low as 15% in the processes which require purification.…”

Porous microspheres support mesenchymal progenitor cell ingrowth and stimulate angiogenesis

“…27 Controlling the processing conditions allows precise control over the degree of porosity within the material along with control over the interconnectivity and to some extent pore size. 28 We have recently demonstrated that the mechanical properties of this copolymer system can be finely tuned by changing the monomer ratios. 29 PolyHIPEs are increasingly being used in tissue engineering applications and as cell culture substrates due to their porosity and interconnectivity.…”

Pickering emulsion-templated polymers: insights into the relationship between surfactant and interconnecting pores

“…Macroporous polymers have extensive applications in many elds, such as tissue engineering scaffolds, [1][2][3][4] controlled release, [5][6][7][8][9] ion adsorption, 10-13 separation 14,15 and supports for catalysis. [16][17][18][19][20] These applications normally require porous polymers with an open-cell structure.…”