A microwave-triggered opening of the multifunctional polyelectrolyte capsules with nanodiamonds in the shell composition

Microcapsules are ideal cargo platform for variety of applications such as drug delivery, sensing and imaging due to the combination of a simplicity fabrication and flexibility in the design. We developed remotely collapsing polymer capsules to response to external microwave treatment. The multilayer structure of the capsules was designed to create a polyfunctional system intercalating with nanodiamonds (NDs) and upconversion nanoparticles (UCNPs) into the polyelectrolyte shell. NDs empower local overheating to the microcapsules, while UCNPs provide opportunity to luminescent thermal sensing. UCNPs consist of inorganic crystalline host matrix - hexagonal beta-phase NaYF4, doped with pairs of trivalent lanthanide ions, which play role of sensitizer (Yb3+) and activator (Er3+). The microwave triggering followed by the capsule heating results in the controlled destruction of the polyelectrolyte shell with subsequent cargo release. UCNPs luminescence was utilized to determine the local temperature of the capsule shell at nanoscale under GHz ultrasonic treatment. Our novel approach provides on demand microcapsule system destruction, which can be used in the development of nanotheranostic platform for the unification of diagnosis and treatment of various diseases.

Automated summary

This study developed remotely collapsing polymer capsules triggered by microwave treatment, achieving precise destruction and drug release through nanodiamonds and upconversion nanoparticles in a multilayer structure. The research provides a new approach for the development of nanotheranostic platform for the unification of diagnosis and treatment.