Janus Particles are asymmetric colloidal structures where two or more different chemical natures are distributed in bulk or surface. This unique asymmetric structure is the source of many interesting properties and applications. In fact, the ability to assemble several different and sometimes contradictory natures on a single particle makes these particles attractive for researchers. Seeded emulsion polymerization is one of the most efficient methods based on phase separation of two different substances due to a powerful driving force. On the other hand, importance of co-delivery and simultaneous detect and treat of cells attracted more attentions towards Janus particles. In this regard, we tried to produce biocompatible pH-sensitive Janus particles via seeded emulsion polymerization based on acrylate monomers and use them in simultaneous loading and release of two drugs. At first cross-linked poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(methacrylic acid) (PMAA) cores as hydrophilic seed particles were synthesized via distillation precipitation polymerization (DPP) and then, MAA, HEMA and 2-dimethylaminoethyl methacrylate (DMAEMA) were used as second hydrophilic monomers to produce Janus particles with different morphologies such as dumbbell-like, snowman-like and cauliflower-like. The morphology, size and size distribution of resultant particles was investigated by field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). In some cases, the formation of core-shell structures was also observed. The effects of different parameters such as feeding approach and composition, polymerization medium, pH-sensitivity of secondary monomer and variation of used surfactant on morphology were investigated. Drug release studies showed that Janus particles can be used in loading and release of two drugs simultaneously. Release behaviors of DOX and ibuprofen were pH dependent and significantly affected by the structure of composite particles.

Fabricating Janus particles using seeded emulsion polymerization: Loading and simultaneous release of two drugs

2019 Fall National Meeting

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