Molecularly imprinted upconversion nanoparticles for active tumor targeting and microinvasive photothermal therapy

Actively tumor-targeted photothermal therapy (PTT) has been regarded as an attractive strategy for tumor treatment. Unfortunately, invasive damage caused by hyperthermia, irrepressible heating transfer and self-heating from in-organism water is always a real ‘hot potato’ in existing PTT modes. Herein, molecularly imprinted upconversion nanoparticles (UCPs@MIPs) were innovatively reported as an artificial antibody for active tumor targeting and microinvasive PTT. UCPs@MIPs were prepared using boronic acid-functionalized upconversion nanoparticles as a substrate, in-water polymerizable dopamine and m-aminophenylboronic acid as a functional co-monomer and photothermal couplant, and sialic acid, a monosaccharide overexpressed on most cancer cells, as a template to create tumor-targeted imprinting cavities. Uniquely, the as-designed UCPs@MIPs were of three-in-one traits, i.e., active tumor targetability, bright upconversion luminescence and superb photothermal properties, enabling to achieve tumor-targeted microinvasive PTT by virtue of semi-accurate hyperthermia tumor ablation while protecting the normal tissue from overheating. Finally, as a proof of concept, such a molecular imprinting technique (MIT)-based PTT mode was successfully applied to real biosystems using HepG2 tumor-bearing mice as tumor models. Since MIT has good versatility in the selection of imprinting methods, substrate materials and template molecules, it will find its wider applications in the fields of biosensing and nanomedicine.