On-demand targeting nanotheranostics with stimuli-responsive releasing property to improve delivery efficiency to cancer

Nanocarriers have great potential to enhance drug delivery efficiency and therapeutic effect for various cancers. However, premature drug leakage and non-specific targeting still limit the delivery efficiency. Here, we present a smart on-demand targeting nanotheranostic system (PO-PB@SPIOs) with stimuli-responsive releasing property to improve the delivery efficiency for ovarian cancer. This delivery system prevents premature drug leakage via boronate ester linkages and shields the targeting moieties (phenylboronic acid) from non-specific binding when circulating in the blood. The PO-PB@SPIOs would release the tumor-targeting payload (PB) in response to the tumor microenvironment. Then, PB was able to target the overexpressed sialic acids on tumor cells. The significant improvement of delivery efficiency was demonstrated in vivo by a significantly enhanced signal in near-infrared-fluorescence (NIRF)/magnetic-resonance (MR) imaging (5-fold higher) and a remarkable photo-thermal therapeutic effect (complete cure rate (CCR) up to 80%). Furthermore, due to the on-demand targeting and stimuli-responsive releasing strategy, this nanotheranostic system shows a greater delivery efficiency even than the active-targeting small molecules or control nanoformulations. We believe this delicate design has great potential to develop novel drug nanoformulation.