Recent developments in Pickering emulsions for biomedical applications

Abstract

Pickering emulsions, stabilised by organic or inorganic particles, offer long-term dispersibility of liquid droplets and resistance to coalescence. The versatility of stabilising particles and their ability to encapsulate and release cargo with high internal payload capacity makes them attractive in a wide variety of applications, ranging from catalysis to the cosmetic and food industry. While these properties make them an equally promising material platform for pharmaceutical and clinical applications, the development of Pickering emulsions for healthcare is still in its infancy. Herein, we summarise and discuss recent progress in the development of Pickering emulsions for biomedical applications, probing their design for passive diffusion-based release as well as stimuli-responsive destabilisation. We further comment on challenges and future directions of this exciting and rapidly expanding area of research.Pickering emulsions have been applied in a number of areas of research and industrial importance, such as food manufacturing, cosmetics, agrochemicals and therapeutic delivery. Their popularity in biomedical applications (i.e. for use in healthcare, such as therapeutics, diagnostics or imaging), in particular, has increased dramatically in recent years, thanks to their high stability, capacity for superior cargo loading compared to conventional systems, and diverse range of stabilising particles, creating a broad library of available building blocks. For biomedical and pharmaceutical application, the choice of emulsifier is critical; it must be biocompatible, non-toxic, and be able to be excreted from the body (if necessary). In this article, we will review the latest developments in the design and application of Pickering emulsions for biomedicine, with a focus on stimuli-responsive Pickering emulsions as a route to the triggered release of a payload towards advanced therapeutic delivery strategies. Within this discussion, we will describe systems which have been applied in proof of concept and in vitro assessments and emphasise areas of potential future development.

Sensory perception of textural properties of cosmetic Pickering emulsions

“…Pickering emulsions, because of their physical stability , can be potentially used as delivery systems of actives in biomedical and food applications , or pharmaceutics and cosmetics , namely for all‐ trans ‐retinol or caffeine skin delivery.…”

Self-assembly of mono- and poly-dispersed nanoparticles on emulsion droplets: antagonistic vs. synergistic effects as a function of particle size

“…For example, in drug delivery applications, pH changes could trigger the release of therapeutics. 22 However, effective NP-NP interactions are the result of multiple phenomena, which might occur simultaneously. For example, McClements and co-workers 23,24 reported extensive droplet flocculation and aggregation near the isoelectric point of particles adsorbed on droplet surfaces, leading to creaming instability.…”

Preparation of chitosan/gum Arabic nanoparticles and their use as novel stabilizers in oil/water Pickering emulsions

“…Emulsion-based systems are widely used as food and cosmetic products, and pharmaceutical dosage forms owing to their facile formulation and enhancement of active agents and drug solubilization (Harman, Patel, Guldin, & Davies, 2019). These systems are typically stabilized by emulsifiers, which are being increasingly associated with environmental and health concerns in the long term.…”