Activatable theranostic nanomedicines involved in photothermal therapy (PTT) have received constant attention as promising alternatives to traditional therapies in clinic. However, the theranostic nanomedicines widely suffer from instability and complicated nanostructures, which hamper potential clinical applications. Herein, we demonstrated a terrylenediimide (TDI)-poly(acrylic acid) (TPA)-based nanomedicine (TNM) platform used as an intrinsic theranostic agent. As an exploratory paradigm in seeking biomedical applications, TDI was modified with poly(acrylic acid)s (PAAs), resulting in eight-armed, star-like TPAs composed of an outside hydrophilic PAA corona and an inner hydrophobic TDI core. TNMs were readily fabricated via spontaneous self-assembly. Without additional vehicle and cargo, the as-prepared TNMs possessed a robust nanostructure and high photothermal conversion efficiency up to approximately 41%. The intrinsic theranostic properties of TNMs for use in photoacoustic (PA) imaging by a multispectral optoacoustic tomography system and in mediating photoinduced tumor ablation were intensely explored. Our results suggested that the TNMs could be successfully exploited as intrinsic theranostic agents for PA imaging-guided efficient tumor PTT. Thus, these TNMs hold great potential for (pre)clinical translational development.
Precision phototheranostics, including photoacoustic imaging and photothermal therapy, requires stable photothermal agents. Developing such agents with high stability and high photothermal conversion efficiency (PTCE) remains a considerable challenge. Herein, we introduce a new photothermal agent based on water‐soluble quaterrylenediimide (QDI) that can self‐assemble into nanoparticles (QDI‐NPs) in aqueous solution. Incorporating polyethylene glycol (PEG) into the QDI core significantly enhances both physiological stability and biocompatibility of QDI‐NPs. The highly photostable QDI‐NPs offer advantages including intense absorption in the near‐infrared (NIR) and high PTCE of up to 64.7±4 %. This is higher than that of commercial indocyanine green (ICG). Their small size (ca. 10 nm) enables sustained retention in deep tumor sites and also proper clearance from the body. QDI‐NPs allow high‐resolution photoacoustic imaging and efficient 808 nm laser‐triggered photothermal therapy of cancer in vivo.
Novel multi‐stimuli‐responsive microcapsules with adjustable controlled‐release characteristics are prepared by a microfluidic technique. The proposed microcapsules are composed of crosslinked chitosan acting as pH‐responsive capsule membrane, embedded magnetic nanoparticles to realize “site‐specific targeting”, and embedded temperature‐responsive sub‐microspheres serving as “micro‐valves”. By applying an external magnetic field, the prepared smart microcapsules can achieve targeting aggregation at specific sites. Due to acid‐induced swelling of the capsule membranes, the microcapsules exhibit higher release rate at specific acidic sites compared to that at normal sites with physiological pH. More importantly, through controlling the hydrodynamic size of sub‐microsphere “micro‐valves” by regulating the environment temperature, the release rate of drug molecules from the microcapsules can be flexibly adjusted. This kind of multi‐stimuli‐responsive microcapsules with site‐specific targeting and adjustable controlled‐release characteristics provides a new mode for designing “intelligent” controlled‐release systems and is expected to realize more rational drug administration.
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