High internal phase emulsions (HIPEs), with densely packed droplets of internal phase and monomers dispersed in the continuous phase, are now an established medium for porous polymer preparation (polyHIPEs). The ability to influence the pore size and interconnectivity, together with the process scalability and a wide spectrum of possible chemistries are important advantages of polyHIPEs. In this review, the focus on the biomedical applications of polyHIPEs is emphasised, in particular the applications of polyHIPEs as scaffolds/supports for biological cell growth, proliferation and tissue (re)generation. An overview of the polyHIPE preparation methodology is given and possibilities of morphology tuning are outlined. In the continuation, polyHIPEs with different chemistries and their interaction with biological systems are described. A further focus is given to combined techniques and advanced applications.

Terpenes, namely limonene, carvone and myrcene were polymerized with multifunctional actylates within high internal phase emulsions to yield bio based macroporous monolithic polymers-polyHIPEs.

A facile method for the preparation of hierarchically porous spherical particles using high internal phase water-in-oil-in-water (w/o/w) double emulsions via the photopolymerization of the water-in-oil high internal phase emulsion (w/o HIPE) was developed. Visible-light photopolymerization was used for the synthesis of microspherical particles. The HIP emulsion had an internal phase volume of 80% and an oil phase containing either thiol pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) or trimethylolpropane tris(3-mercaptopropionate) (TMPTMP) and acrylate trimethylolpropane triacrylate (TMPTA). This enabled the preparation of microspheres with an open porous morphology, on both the surface and within the microsphere, with high yields in a batch manner. The effect of the thiol-to-acrylate ratio on the microsphere diameter, pore and window diameter, and degradation was investigated. It is shown that thiol has a minor effect on the microsphere and pore diameter, while the acrylate ratio affects the degradation speed, which decreases with increasing acrylate content. The possibility of free thiol group functionalization was demonstrated by a reaction with allylamine, while the microsphere adsorption capabilities were tested by the adsorption of methylene blue.