Liang Zhao,Han Zhu,You-Yang Duo,Dai-Wen Pang,Zhi-Gang Wang,Shu-Lin Liu
The serious threat that cancer poses to human health highlights the significance of early detection and effective treatment. The integration of fluorescence diagnosis and photothermal therapy in NIR-II has gained attention due to its high sensitivity, fast response, and non-invasiveness. Fluorescence, produced by the radiative relaxation process of electrons in a molecule, and photothermal, generated by the non-radiative relaxation process of electrons in a molecule, are competing photophysical processes. Hence, it is a challenge for the molecule to balance between the properties of fluorescence and photothermal. In this study, we designed a NIR-II hemicyanine with TICT character to obtain molecules with both better fluorescence and photothermal properties, utilizing positively charged pyridine salt and triphenylamine as electron acceptor and donor, respectively, and oxole as the conjugated π-bridge. HCY-995 , one of the synthesized compounds, had a quantum yield of 0.09%, photothermal conversion efficiency of 54.90%, and a significant Stoke shift of 232 nm, which made it appropriate for the integration of photothermal therapy and high-resolution imaging. This study provides new insights into the development of NIR-II molecules with fluorescent and photothermal integrated properties. This article is protected by copyright. All rights reserved
Micro/nanorobots have been extensively explored as a tetherless small-scale robotic biodevice to perform minimally invasive interventions in hard-to-reach regions. Despite the emergence of versatile micro/nanorobots in recent years, matched in vivo development remains challenging, limited by unsatisfactory integration of core functions. Herein, we report a polydopamine (PDA)-coated magnetic microswimmer consisting of a magnetized Spirulina (MSP) matrix and PDA surface. Apart from the properties of the existing MSP (e.g., robust propulsion, natural fluorescence, tailored biodegradation, and selective cytotoxicity), the introduced PDA coating enhances the photoacoustic (PA) signal and photothermal effect of the MSP, thus making PA image tracking and photothermal therapy possible. Meanwhile, the PDA’s innate fluorescence quenching and diverse surface reactivity allows an off–on fluorescence diagnosis with fluorescence probes (e.g., coumarin 7). As a proof of concept, real-time image tracking (by PA imaging) and desired theranostic capabilities of PDA-MSP microswimmer swarms are demonstrated for the treatment of pathogenic bacterial infection. Our study suggests a feasible antibacterial microrobot for in vivo development and a facile yet versatile functionalization strategy of micro/nanorobots.
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