Smart Microcapsules Designed for On-Demand Local Heating and Drug Release

Abstract

Chemophotothermal therapy is promising for cancer treatmentwithits synergistic effect. Although various photothermal agents havebeen formulated as drug carriers, low payload, burst release, andsevere dilution usually restrict their uses. To overcome the limitations,we design smart microcapsules as a pragmatic material for chemophotothermaltherapy. With a microfluidic device, water-in-oil-in-water (W/O/W)double-emulsion templates are produced to have photothermal polydopaminenanoparticles and drugs in the water core and a mixture of photocurablemonomers and phase-change material (PCM) in the oil shell. The dropletsare significantly shrunken by the osmotic extraction of water fromthe core, which enables the size reduction for the ease of injectionand enrichment of polydopamine nanoparticles and drugs for enhancedphotothermal performance and high payload. The microcapsules, producedby photopolymerization of monomers, release drugs when PCM in continuousnanochannels of the polymer shell is molten while retaining drugswithout leakage when frozen. As the concentrated polydopamine nanoparticlesprovide rapid and drastic heating by near-infrared irradiation, thedrug release can be switched on and off in a programmed manner bymanipulating the irradiation. The smart microcapsules secure highdrug payload in a spacious core, negligible initial bursting, anddilution-free high photothermal performance, potentially serving asa pragmatic therapy platform.