Carrier‐Free Biomimetic Organic Nanoparticles with Super‐High Drug Loading for Targeted NIR‐II Excitable Triple‐Modal Bioimaging and Phototheranostics

Abstract Multimodal near‐infrared II (NIR‐II) theranostics combined with nanotechnology have emerged as promising treatments for cancer due to their noninvasive and high spatiotemporal nature. Traditional NIR‐II theranostics typically comprise useless and massive inert carriers, resulting in low drug loading capacity, reduced therapeutic effects, and potential biotoxicity. To overcome these limitations, this work reports carrier‐free NIR‐II theranostics simultaneously with high drug loading capacity and multimodal NIR‐II imaging capabilities for cancer phototheranostics in the NIR‐II window. Carrier‐free BTA nanoparticles (NPs) are prepared by self‐assembling the NIR‐II responsive conjugated oligomer BTA without adding coating agents; these NPs exhibited 100% drug loading and high‐performance NIR‐II theranostic capabilities. Cancer cell membranes are camouflaged on carrier‐free BTA NPs to provide homologous targeting ability, enhanced stability, and 77.8% drug loading. Both in vitro and in vivo studies have indicated that biomimetic NPs provide efficient triple‐modal guidance for NIR‐II fluorescence, photoacoustic, and photothermal imaging and complete tumor elimination via photothermal therapy (PTT). Additionally, theranostics‐based treatments with good biosecurity are demonstrated. This study contributes a new strategy for the design of high‐drug‐loading NIR‐II theranostics and further promotes the clinical translation of theranostic agents.