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Infectious diseases caused by bacteria are a global threat to the human health. Here, we propose a solvent “irrigation” technique to endow TiO2 nanotubes (NTs) to precisely modify with functional nanomaterials, and apply them in constructing a near-infrared (NIR) light controlled drug-delivery system for rapid necrosis of bacteria. In this design, the NIR stimuli-responsive functional shell is located on the external tube wall of TiO2 NT; the internal tube wall offers sufficient binding sites for drug loading. Using kanamycin as a model drug, we demonstrate that the reactive oxygen species generated in photocatalysis not only controllably release the loaded drug by scissoring the linked chains, but also effectively compromise bacteria membrane integrity by damaging the cell wall. Benefiting from the damages, antibiotics rapidly enter the bacteria and reach ≥99.9% reduction in Escherichia coli colony within only 2 h. Importantly, such a covalently conjugation-based delivery system can efficiently relieve radical-induced inflammation and cytotoxicity. This study provides an innovative design strategy for engineering delivery systems with tailorable components, enduring stimuli-response by multiple triggers.

Bufalin is efficacious in treating various tumors, however, the clinical application of which is restricted by the myocardial toxicity. Developing a smart synergetic delivery system is widely considered as a promising therapeutic strategy. To address this issue, a black phosphorus hybrid polypeptides hydrogel was designed to highly load bufalin, and achieved near-infrared (NIR)-controllable drug release with synergistic photothermal-chemo therapeutic effect. Black phosphorus nanosheets (BPNSs) and bufalin were co-loaded in temperature-sensitive supramolecular hydrogel to receive smart hybridization (BP-bufalin@SH). With NIR irradiation (1 W·cm−2), BP-bufalin@SH exhibited a rapid and large temperature increase and released bufalin via light-controllable manner, with which the side effects of bufalin were greatly decreased. Combined with photothermal-chemo therapeutic effect, BP-bufalin@SH could collapse the mitochondrial transmembrane potential resulting in the irreversible apoptosis of tumor cells, and realize a highly efficient in vivo tumor elimination with good biosafety and biocompatibility. This work provides a new hydrogel platform for controlling bufalin release, and thus further promotes the practical application on antitumor therapy.

Significant attenuation and overheating, caused by the absorption of the excitation band (980 nm) in water, are the major obstacles in the in vivo application of lanthanide-doped upconversion nanoparticles (UCNPs). Therefore, appropriately-structured Nd3+-doped UCNPs with 808 nm excitation could be a promising alternative. Herein, we developed core–shell–shell structured Nd3+-sensitized UCNPs as imaging agents, and decorated them onto the surface of polydopamine (PDA) to construct a novel multifunctional core/satellite nanotheranostic (PDA@UCNPs) for in vivo imaging guidance photothermal therapy using single 808 nm laser irradiation. The core–shell–shell structured design enabled outstanding upconversion luminescence properties and strong X-ray attenuation, thereby making the nanocomposites potential candidates for excellent upconversion luminescence/computed tomography dual modal imaging. In addition, the PDA core not only provides high photothermal conversion efficiency and outstanding antitumor effect, but also endows the platform with robust biocompatibility owing to its natural features. Therefore, this multifunctional nanocomposite could be a promising theranostic in future oncotherapy, with high therapeutic effectiveness but low side effects. This study would stimulate interest in designing bio-application-compatible multifunctional nanocomposites, especially for cancer diagnosis and treatment in vivo.

Accurate regulation of cellular zinc signaling is imperative to decipher underlying zinc functions and develop new therapeutic agents. However, the ability to modulate zinc in a spatiotemporal manner remains elusive. We herein report an intelligent spiropyran-upconversion (SP-UCNPs) based nanosystem that enables near-infrared (NIR) light-controlled zinc release at precise times and locations. The magnitude of zinc release can be simply manipulated by varying the duration of NIR irradiation. Moreover, the utilization of NIR light not only showed little damage to cells but also significantly improved penetration depth. By evaluating activity of a model protein, phosphatase 2A, we further validated zinc signaling activation. Importantly, our strategy may be broadly applicable to other types of metal ions, like the ubiquitous second messenger calcium. More importantly, our strategy can potentially enable the precise control of specific signaling pathways of metal ions while minimizing cellular damage, facilitating the advanced manipulation of cellular dynamics.

Persistent luminescence nanoparticles (PLNPs) and upconversion nanoparticles (UCNPs) are two special optical imaging nanoprobes. In this study, efficient upconverted persistent luminescence (UCPL) is realized by combining their unique features into polymethyl methacrylate, forming a film composed of both PLNPs and UCNPs. The red persistent luminescence (~640 nm) of the PLNPs (CaS:Eu,Tm,Ce) can be activated by upconverted green emission of UCNPs (β-NaYF4:Yb,Er@NaYF4) excited by near-infrared light (NIR). Using this strategy, both the unique optical properties of PLNPs and UCNPs can be optimally synergized, thus generating efficient upconversion, photoluminescence, and UCPL simultaneously. The UCPL system has potential applications in in vivo bioimaging by simply monitoring the biocompatible low power density of NIR-light-excited persistent luminescence. Due to its simplicity, we anticipate that this method for the preparation of UCPL composite can be easily adjusted using other available upconversion and persistent phosphor pairs for a number of biophotonic and photonic applications.

We report a fuel-free, near-infrared (NIR)-driven Janus microcapsule motor. The Janus microcapsule motors were fabricated by template-assisted polyelectrolyte layer-by-layer assembly, followed by spraying of a gold layer on one side. The NIR-powered Janus motors achieved high propulsion with a maximum speed of 42 µm·s-1 in water. The propulsion mechanism of the Janus motor was attributed to the self-thermophoresis effect: The asymmetric distribution of the gold layer generated a local thermal gradient, which in turn generated thermophoretic force to propel the Janus motor. Such NIR-propelled Janus capsule motors can move efficiently in cell culture medium and have no obvious effects on the cell at the power of the NIR laser, indicating considerable promise for future biomedical applications.

The photothermal therapy (PTT) technique is regarded as a promising method for cancer treatment. However, one of the obstacles preventing its clinical application is the non-degradability and biotoxicity of the existing heavy-metal and carbon-based therapeutic agents. Therefore, a PTT material with a high photothermal efficiency, low toxicity, and good biocompatibility is urgently wanted. Herein, we report a titanium oxide-based therapeutic agent with a high efficacy and low toxicity for the PTT process. We demonstrated that Magneli-phase Ti8O15 nanoparticles fabricated by the arc-melting method exhibit >98% absorption of near infrared light and a superior photothermal therapy effect in the in vivo mouse model. The Ti8O15 nanoparticle PTT material also shows a good biocompatibility and biosafety. Our study reveals Magneli-phase titanium oxide as a new family of PTT agents and introduces new applications of titanium oxides for photothermal conversion.