Mechanistic formation of drug-encapsulated Janus particles through emulsion solvent evaporation

Abstract

Janus particles are emerging as structurally unique drug carriers with the potential to deliver multiple drugs and agents. Although synthesis methods have been extensively explored to fabricate Janus particles, it remains a challenge to generate drug-loaded Janus particles through an economical, high throughput technique. Here, we report the formation of the first drug-loaded, micro-scale Janus particles prepared using a single-step emulsion solvent evaporation approach. Our results revealed that both the net charge of drug molecules (i.e. glibenclamide, tolbutamine, rapamycin and lidocaine) and polymer weight ratio (i.e.poly(lactic-co-glycolic) and polycaprolactone) were critical in determining the formation of Janus particles.The formation of drug-loaded Janus particles was proven to be thermodynamically-driven in accordance to the classical equilibrium spreading coefficient theory, which is strongly governed by interfacial tensions.Specifically, comparable interfacial tensions between the two interacting polymers with the water phase were identified to be key criteria to achieve the Janus particles hemispheric structure. Such interfacial tensions were amenable, and were found to be highly dependent on the interfacial charge density attributed to both drug and polymer ratio. Hereby, this study provides a mechanistic insight into the fabrication of drug-loaded Janus particles and paves an important path towards large-scale production of Janus particles using a simplified, single-step emulsion solvent evaporation strategy.

Synthesis of Polymeric Janus Superstructures via a Facile Synthesis Method

“…[ 22–25 ] To begin, their baseline interfacial tension values (γ 12 , γ 13 , γ 23 ) at their optimal weight ratios were first measured, and these values are summarized in Table S1 in the Supporting Information. These three polymer combinations have also been shown to be able to form Janus particles by varying weight ratios, [ 20,21 ] and are also documented in Table S2 in the Supporting Information.…”

“…subsequently documented the mechanistic effect of drug addition to Janus particles, reporting how drugs can affect polymer interfacial tensions thereby shaping the final particle morphology. [ 20 ] Using data on interfacial tensions, a broad range of polymeric Janus particles (i.e., drug‐loaded, surface functionalized, etc.) can now be produced through solvent emulsion.…”

“…Previous reports have systematically shown that thermodynamics is the main driving force for the formation of Janus particles via the solvent emulsion method, [ 9,20,21 ] In solvent emulsion, there are three interfaces arising from the three phases (phases one and three are polymer solutions, and phase two is the aqueous solution). These interfaces are with respect to the individual polymers and the aqueous solution (γ 12 and γ 23 ), as well as the interface between both polymers (γ 13 ) (Figure S1a, Supporting Information).…”

“…Based on Fan et al., the authors proposed an additional requirement, |γ 12 − γ 23 | < γ 13 , as a possible extension to the HSC theory to achieve Janus particles. [ 20 ] Thus, to favor the formation of Janus particles, the polymer‐to‐polymer interfacial tension (γ 13 ) value would have to be as high as possible. A high γ 13 value can buffer changes to the interfacial tensions, while still keeping to the above criteria, and thus favoring Janus particles formation.…”

Magneto-thermochromic coupling Janus sphere for dual response display

“…Janus spheres (JPs) are made up of two or more different materials, and the surface of JPs can even produce two distinct types of chemical reactions on a single sphere. 1 Due to their biphasic characteristic, JPs have received increasing attention in remote manipulation, 2,3 drug delivery, 4 switchable display devices, [5][6][7][8][9][10] imaging, and magnetoelastic therapy. 11 Many approaches have been developed to fabricate JPs, including masking, 12 self-assembly, 13 phase separation, 14 physical vapor deposition 15 and microuidics.…”