pH‐ and NIR Light‐Responsive Polymeric Prodrug Micelles for Hyperthermia‐Assisted Site‐Specific Chemotherapy to Reverse Drug Resistance in Cancer Treatment

Despite the exciting advances in cancer chemotherapy over past decades, drug resistance in cancer treatment remains one of the primary reasons for therapeutic failure. IR‐780 loaded pH‐responsive polymeric prodrug micelles with near infrared (NIR) photothermal effect are developed to circumvent the drug resistance in cancer treatment. The polymeric prodrug micelles are stable in physiological environment, while exhibit fast doxorubicin (DOX) release in acidic condition and significant temperature elevation under NIR laser irradiation. Phosphorylcholine‐based biomimetic micellar shell and acid‐sensitive drug conjugation endow them with prolonged circulation time and reduced premature drug release during circulation to conduct tumor site‐specific chemotherapy. The polymeric prodrug micelles combined with NIR laser irradiation could significantly enhance intracellular DOX accumulation and synergistically induce the cell apoptosis in DOX‐resistant MCF‐7/ADR cells. Meanwhile, the tumor site‐specific chemotherapy combined with hyperthermia effect induces significant inhibition of MCF‐7/ADR tumor growth in tumor‐bearing mice. These results demonstrate that the well‐designed IR‐780 loaded polymeric prodrug micelles for hyperthermia‐assisted site‐specific chemotherapy present an effective approach to reverse drug resistance.     

Multifunctional RbxWO3 Nanorods for Simultaneous Combined Chemo‐photothermal Therapy and Photoacoustic/CT Imaging

Light‐triggered drug delivery based on near‐infrared (NIR)‐mediated photothermal nanocarriers has received tremendous attention for the construction of cooperative therapeutic systems in nanomedicine. Herein, a new paradigm of light‐responsive drug carrier that doubles as a photothermal agent is reported based on the NIR light‐absorber, Rb _x WO₃ (rubidium tungsten bronze, Rb‐TB) nanorods. With doxorubicin (DOX) payload, the DOX‐loaded Rb‐TB composite (Rb‐TB‐DOX) simultaneously provides a burst‐like drug release and intense heating effect upon 808‐nm NIR light exposure. MTT assays show the photothermally enhanced antitumor activity of Rb‐TB‐DOX to the MCF‐7 cancer cells. Most remarkably, Rb‐TB‐DOX combined with NIR irradiation also shows dramatically enhanced chemotherapeutic effect to DOX‐resistant MCF‐7 cells compared with free DOX, demonstrating the enhanced efficacy of combinational chemo‐photothermal therapy for potentially overcoming drug resistance in cancer chemotherapy. Furthermore, in vivo study of combined chemo‐photothermal therapy is also conducted and realized on pancreatic (Pance‐1) tumor‐bearing nude mice. Apart from its promise for cancer therapy, the as‐prepared Rb‐TB can also be employed as a new dual‐modal contrast agent for photoacoustic tomography and (PAT) X‐ray computed tomography (CT) imaging because of its high NIR optical absorption capability and strong X‐ray attenuation ability, respectively. The results presented in the current study suggest promise of the multifunctional Rb _x WO₃ nanorods for applications in cancer theranostics.     

A Self‐Assembled DNA Origami‐Gold Nanorod Complex for Cancer Theranostics

A self‐assembled DNA origami (DO)‐gold nanorod (GNR) complex, which is a dual‐functional nanotheranostics constructed by decorating GNRs onto the surface of DNA origami, is demonstrated. After 24 h incubation of two structured DO‐GNR complexes with human MCF7 breast cancer cells, significant enhancement of cell uptake is achieved compared to bare GNRs by two‐photon luminescence imaging. Particularly, the triangle shaped DO‐GNR complex exhibits optimal cellular accumulation. Compared to GNRs, improved photothermolysis against tumor cells is accomplished for the triangle DO‐GNR complex by two‐photon laser or NIR laser irradiation. Moreover, the DO‐GNR complex exhibits enhanced antitumor efficacy compared with bare GNRs in nude mice bearing breast tumor xenografts. The results demonstrate that the DO‐GNR complex can achieve optimal two‐photon cell imaging and photothermal effect, suggesting a promising candidate for cancer diagnosis and therapy both in vitro and in vivo.     

Recent Progress on Bioinspired Self‐Propelled Micro/Nanomotors via Controlled Molecular Self‐Assembly

The combination of bottom‐up controllable self‐assembly technique with bioinspired design has opened new horizons in the development of self‐propelled synthetic micro/nanomotors. Over the past five years, a significant advances toward the construction of bioinspired self‐propelled micro/nanomotors has been witnessed based on the controlled self‐assembly technique. Such a strategy permits the realization of autonomously synthetic motors with engineering features, such as sizes, shapes, composition, propulsion mechanism, and function. The construction, propulsion mechanism, and movement control of synthetic micro/nanomotors in connection with controlled self‐assembly in recent research activities are summarized. These assembled nanomotors are expected to have a tremendous impact on current artificial nanomachines in future and hold potential promise for biomedical applications including drug targeted delivery, photothermal cancer therapy, biodetoxification, treatment of atherosclerosis, artificial insemination, crushing kidney stones, cleaning wounds, and removing blood clots and parasites.     

Self‐Organized Multiconstituent Catalytic Nanomotors

Self‐organized catalytic nanomotors consisting of more than one individual component are presented. Tadpole‐like catalytic nanomotors fabricated by dynamic shadowing growth (DSG) self‐organize randomly to form two‐nanomotor clusters (≈1–3% yield) that spin as opposed to circular motion exhibited by the individual structures. By introducing magnetic materials to another system, self‐assembled “helicopter” nanomotors consisting of a V‐shaped nanomotor and a microbead are formed with ≈25% yield, showing a significantly higher yield than the control (0%). A flexible swimmer system that performs complex swimming, such as maneuvering around stationary objects, is also presented. These nanomotor systems are inherently more complex than those previously studied and may be the next step towards building sophisticated multifunctional nanomachinery systems.     

A Smart Responsive Dual Aptamers‐Targeted Bubble‐Generating Nanosystem for Cancer Triplex Therapy and Ultrasound Imaging

The absence of targeted, single treatment methods produces low therapeutic value for treating cancers. To increase the accumulation of drugs in tumors and improve the treatment effectiveness, near‐infrared 808 nm photothermal responsive dual aptamers‐targeted docetaxel (DTX)‐containing nanoparticles is proposed. In this system, DTX and NH₄HCO₃ are loaded in thermosensitive liposomes. The surface of liposomes is coated with gold nanoshells and connected with sulfydryl (SH? ) modified AS1411 and S2.2 aptamers. The nanosystem has good biocompatibility and uniform size (diameter about 200 nm). The drug is rapidly released, reaching a maximum amount (84%) at 4 h under 808 nm laser irradiation. The experiments conducted in vitro and in vivo demonstrate the nanosystem can synergistically inhibit tumor growth by combination of chemotherapy, photothermal therapy, and biological therapy. Dual ligand functionalization significantly increases cellular uptake on breast cancer cell line (MCF‐7) cells and achieves ultrasound imaging (USI) at tumor site. The results indicate that this drug delivery system is a promising theranostic agent involving light‐thermal response at tumor sites, dual ligand targeted triplex therapy, and USI.     

Rhenium‐188 Labeled Tungsten Disulfide Nanoflakes for Self‐Sensitized,Near‐Infrared Enhanced Radioisotope Therapy

Radioisotope therapy (RIT), in which radioactive agents are administered or implanted into the body to irradiate tumors from the inside, is a clinically adopted cancer treatment method but still needs improvement to enhance its performances. Herein, it is found that polyethylene glycol (PEG) modified tungsten disulfide (WS₂) nanoflakes can be easily labeled by ¹⁸⁸Re, a widely used radioisotope for RIT, upon simple mixing. Like other high‐Z elements acting as radiosensitizers, tungsten in the obtained ¹⁸⁸Re‐WS₂‐PEG would be able to absorb ionization radiation generated from ¹⁸⁸Re, enabling ‘‘self‐sensitization’’ to enhance the efficacy of RIT as demonstrated in carefully designed in vitro experiments of this study. In the meanwhile, the strong NIR absorbance of WS₂‐PEG could be utilized for NIR light‐induced photothermal therapy (PTT), which if applied on tumors would be able to greatly relieve their hypoxia state and help to overcome hypoxia‐associated radioresistance of tumors. Therefore, with ¹⁸⁸Re‐WS₂‐PEG as a multifunctional agent, which shows efficient passive tumor homing after intravenous injection, in vivo self‐sensitized, NIR‐enhanced RIT cancer treatment is realized, achieving excellent tumor killing efficacy in a mouse tumor model. This work presents a new concept of applying nanotechnology in RIT, by delivering radioisotopes into tumors, self‐sensitizing the irradiation‐induced cell damage, and modulating the tumor hypoxia state to further enhance the therapeutic outcomes.     

Nanocatalysts‐Augmented and Photothermal‐Enhanced Tumor‐Specific Sequential Nanocatalytic Therapy in Both NIR‐I and NIR‐II Biowindows

The tumor microenvironment (TME) has been increasingly recognized as a crucial contributor to tumorigenesis. Based on the unique TME for achieving tumor‐specific therapy, here a novel concept of photothermal‐enhanced sequential nanocatalytic therapy in both NIR‐I and NIR‐II biowindows is proposed, which innovatively changes the condition of nanocatalytic Fenton reaction for production of highly efficient hydroxyl radicals (?OH) and consequently suppressing the tumor growth. Evidence suggests that glucose plays a vital role in powering cancer progression. Encouraged by the oxidation of glucose to gluconic acid and H₂O₂ by glucose oxidase (GOD), an Fe₃O₄/GOD‐functionalized polypyrrole (PPy)‐based composite nanocatalyst is constructed to achieve diagnostic imaging‐guided, photothermal‐enhanced, and TME‐specific sequential nanocatalytic tumor therapy. The consumption of intratumoral glucose by GOD leads to the in situ elevation of the H₂O₂ level, and the integrated Fe₃O₄ component then catalyzes H₂O₂ into highly toxic ?OH to efficiently induce cancer‐cell death. Importantly, the high photothermal‐conversion efficiency (66.4% in NIR‐II biowindow) of the PPy component elevates the local tumor temperature in both NIR‐I and NIR‐II biowindows to substaintially accelerate and improve the nanocatalytic disproportionation degree of H₂O₂ for enhancing the nanocatalytic‐therapeutic efficacy, which successfully achieves a remarkable synergistic anticancer outcome with minimal side effects.     

A High‐Sensitivity and Low‐Power Theranostic Nanosystem for Cell SERS Imaging and Selectively Photothermal Therapy Using Anti‐EGFR‐Conjugated Reduced Graphene Oxide/Mesoporous Silica/AuNPs Nanosheets

A high‐sensitivity and low‐power theranostic nanosystem that combines with synergistic photothermal therapy and surface‐enhanced Raman scattering (SERS) mapping is constructed by mesoporous silica self‐assembly on the reduced graphene oxide (rGO) nanosheets with nanogap‐aligned gold nanoparticles (AuNPs) encapsulated and arranged inside the nanochannels of the mesoporous silica layer. Rhodamine 6G (R6G) as a Raman reporter is then encapsulated into the nanochannels and anti‐epidermal growth factor receptor (EGFR) is conjugated on the nanocomposite surface, defined as anti‐EGFR‐PEG‐rGO@CPSS‐Au‐R6G, where PEG is polyethylene glycol and CPSS is carbon porous silica nanosheets. SERS spectra results show that rGO@CPSS‐Au‐R6G enhances 5 × 10⁶ magnification of the Raman signals and thus can be applied in the noninvasive cell tracking. Furthermore, it displays high sensitivity (detection limits: 10^?8m R6G solution) due to the “hot spots” effects by the arrangements of AuNPs in the nanochannels of mesoporous silica. The highly selective targeting of overexpressing EGFR lung cancer cells (A549) is observed in the anti‐EGFR‐PEG‐rGO@CPSS‐Au‐R6G, in contrast to normal cells (MRC‐5). High photothermal therapy efficiency with a low power density (0.5 W cm^?2) of near‐infrared laser can be achieved because of the synergistic effect by conjugated AuNPs and rGO nanosheets. These results demonstrate that the anti‐EGFR‐PEG‐rGO@CPSS‐Au‐R6G is an excellent new theranostic nanosystem with cell targeting, cell tracking, and photothermal therapy capabilities.     

Biomimetic Platelet‐Camouflaged Nanorobots for Binding and Isolation of Biological Threats

One emerging and exciting topic in robotics research is the design of micro‐/nanoscale robots for biomedical operations. Unlike industrial robots that are developed primarily to automate routine and dangerous tasks, biomedical nanorobots are designed for complex, physiologically relevant environments, and tasks that involve unanticipated biological events. Here, a biologically interfaced nanorobot is reported, made of magnetic helical nanomotors cloaked with the plasma membrane of human platelets. The resulting biomimetic nanorobots possess a biological membrane coating consisting of diverse functional proteins associated with human platelets. Compared to uncoated nanomotors which experience severe biofouling effects and hence hindered propulsion in whole blood, the platelet‐membrane‐cloaked nanomotors disguise as human platelets and display efficient propulsion in blood over long time periods. The biointerfaced nanorobots display platelet‐mimicking properties, including adhesion and binding to toxins and platelet‐adhering pathogens, such as Shiga toxin and Staphylococcus aureus bacteria. The locomotion capacity and platelet‐mimicking biological function of the biomimetic nanomotors offer efficient binding and isolation of these biological threats. The dynamic biointerfacing platform enabled by platelet‐membrane cloaked nanorobots thus holds considerable promise for diverse biomedical and biodefense applications.     

Programmable NIR‐II Photothermal‐Enhanced Starvation‐Primed Chemodynamic Therapy using Glucose Oxidase‐Functionalized Ancient Pigment Nanosheets

Chemodynamic therapy (CDT) has attracted considerable attention recently, but the poor reaction kinetics restrict its practical utility in clinic. Herein, glucose oxidase (GOx) functionalized ancient pigment nanosheets (SrCuSi₄O₁₀, SC) for programmable near‐infrared II (NIR‐II) photothermal‐enhanced starvation primed CDT is developed. The SC nanosheets (SC NSs) are readily exfoliated from SC bulk suspension in water and subsequently functionalized with GOx to form the nanocatalyst (denoted as SC@G NSs). Upon laser irradiation, the photothermal effect of SC NSs can enhance the catalytic activity of GOx for NIR‐II photothermal‐enhanced starvation therapy, which effectively eliminates intratumoral glucose and produces abundant hydrogen peroxide (H₂O₂). Importantly, the high photothermal‐conversion efficiency (46.3%) of SC@G NSs in second biological window permits photothermal therapy of deep‐seated tumors under the guidance of NIR‐II photoacoustic imaging. Moreover, the acidity amplification due to gluconic acid generation will in turn accelerate the degradation of SC NSs, facilitating the release of strontium (Sr) and copper (Cu) ions. Both the elevated H₂O₂ and the released ions will prime the Cu²⁺/Sr²⁺‐H₂O₂ reaction for enhanced CDT. Thus, a programmable NIR‐II photothermal‐enhanced starvation primed CDT is established to combat cancer with minimal side effects.     

Polyaniline Nanovesicles for Photoacoustic Imaging‐Guided Photothermal‐Chemo Synergistic Therapy in the Second Near‐Infrared Window

Photoacoustic imaging‐guided photothermal therapy in the second near‐infrared (NIR‐II) window shows promise for clinical deep‐penetrating tumor phototheranostics. However, ideal photothermal agents in the NIR‐II window are still rare. Here, the emeraldine salt of polyaniline (PANI‐ES), especially synthesized by a one‐pot enzymatic reaction on sodium bis(2‐ethylhexyl) sulfosuccinate (AOT) vesicle surface (PANI‐ES@AOT, λ_max ≈ 1000 nm), exhibits excellent dispersion in physiological environment and remarkable photothermal ability at pH 6.5 (photothermal conversion efficiency of 43.9%). As a consequence of the enhanced permeability and retention effect of tumors and the doping‐induced photothermal effect of PANI‐ES@AOT, this pH‐sensitive NIR‐II photothermal agent allows tumor acidity phototheranostics with minimized pseudosignal readout and subdued normal tissue damage. Moreover, the enhanced fluidity of vesicle membrane triggered by heating is beneficial for drug release and allows precise synergistic therapy for an improved therapeutic effect. This study highlights the potential of template‐oriented (or interface‐confined) enzymatic polymerization reactions for the construction of conjugated polymers with desired biomedical applications.     

Smart Carbon Nanotubes with Laser‐Controlled Behavior in Gene Delivery and Therapy through a Non‐Digestive Trafficking Pathway

Near‐infrared (NIR) laser‐controlled gene delivery presents some benefits in gene therapy, inducing enhanced gene transfection efficiency. In this study, a “photothermal transfection” agent is obtained by wrapping poly(ethylenimine)‐cholesterol derivatives (PEI‐Chol) around single‐walled carbon nanotubes (SWNTs). The PEI‐Chol modified SWNTs (PCS) are effective in compressing DNA molecules and protecting them from DNaseI degradation. Compared to the complexes formed by PEI with DNA (PEI/DNA), complexes of PCS and DNA that are formed (PCS/DNA) exhibit a little lower toxicity to HEK293 and HeLa cells under the same PEI molecule weight and weight ratios. Notably, caveolae‐mediated cellular uptake of PCS/DNA occurs, which results in a safer intracellular transport of the gene due to the decreased lysosomal degradation in comparison with that of PEI/DNA whose internalization mainly depends on clathrin rather than caveolae. Furthermore, unlike PEI/DNA, PCS/DNA exhibits a photothermal conversion ability, which promotes DNA release from PCS under NIR laser irradiation. The NIR laser‐mediated photothermal transfection of PCS_10K/plasmid TP53 (pTP53) results in more apoptosis and necrosis of HeLa cells in vitro than other groups, and achieves a higher tumor‐growth inhibition in vivo than naked pTP53, PEI_25K/pTP53, and PCS_10K/pTP53 alone. The enhanced transfection efficiency of PCS/DNA can be attributed to more efficient DNA internalization into the tumor cells, promotes detachment of DNA from PCS under the mediation of NIR laser and higher DNA stability in the cells due to caveolae‐mediated cellular uptake of the complexes.     

Flexible Photothermal Assemblies with Tunable Gold Patterns for Improved Imaging‐Guided Synergistic Therapy

Self‐assembly of gold nanoparticles demonstrates a promising approach to realize enhanced photoacoustic imaging (PAI) and photothermal therapy (PTT) for accurate diagnosis and efficient cancer therapy. Herein, unique photothermal assemblies with tunable patterns of gold nanoparticles (including arcs, rings, ribbons, and vesicles) on poly(lactic‐co‐glycolic acid) (PLGA) spheres are constructed taking advantage of emulsion‐confined and polymer‐directed self‐assembly strategies. The influencing factors and formation mechanism to produce the assemblies are investigated in details. Both the emulsion structure and migration behaviors of amphiphilic block copolymer tethered gold nanoparticles are found to contribute to the formation of versatile photothermal assemblies. Hyaluronic acid‐modified R‐PLGA‐Au (RPA) exhibits outstanding photothermal performances under NIR laser irradiation, which is induced by strong plasmonic coupling between adjacent gold nanoparticles. It is interesting that secondary assembly of RPA can be triggered by NIR laser irradiation. Prolonged residence time in tumors is achieved after RPA assemblies are fused into superstructures with larger sizes, realizing real‐time monitoring of the therapeutic processes via PAI with enhanced photoacoustic signals. Notably, synergistic effect resulting from PTT‐enhanced chemotherapy is realized to demonstrate high antitumor performance. This work provides a facile strategy to construct flexible photothermal assemblies with favorable properties for imaging‐guided synergistic therapy.     

Ultrastable Near‐Infrared Conjugated‐Polymer Nanoparticles for Dually Photoactive Tumor Inhibition

It is highly desired that satisfactory photoactive agents with ideal photophysical characteristics are explored for potent cancer phototherapeutics. Herein, bifunctional nanoparticles of low‐bandgap donor–acceptor (D–A)‐type conjugated‐polymer nanoparticles (CP‐NPs) are developed to afford a highly efficient singlet‐to‐triplet transition and photothermal conversion for near‐infrared (NIR) light‐induced photodynamic (PDT)/photothermal (PTT) treatment. CP‐NPs display remarkable NIR absorption with the peak at 782 nm, and perfect resistance to photobleaching. Photoexcited CP‐NPs undergo singlet‐to‐triplet intersystem crossing through charge transfer in the excited D–A system and simultaneous nonradiative decay from the electron‐deficient electron acceptor isoindigo derivative under single‐wavelength NIR light irradiation, leading to distinct singlet oxygen quantum yield and high photothermal conversion efficiency. Moreover, the CP‐NPs display effective cellular uptake and cytoplasmic translocation from lysosomes, as well as effective tumor accumulation, thus promoting severe light‐triggered damage caused by favorable reactive oxygen species (ROS) generation and potent hyperthermia. Thus, CP‐NPs achieve photoactive cell damage through their photoconversion ability for synergistic PDT/PTT treatment with tumor ablation. The proof‐of‐concept design of D–A‐type conjugated‐polymer nanoparticles with ideal photophysical characteristics provides a general approach to afford potent photoactive cancer therapy.     

Glutathione Depletion in a Benign Manner by MoS2‐Based Nanoflowers for Enhanced Hypoxia‐Irrelevant Free‐Radical‐Based Cancer Therapy

Tumor hypoxia significantly diminishes the efficacy of reactive oxygen species (ROS)‐based therapy, mainly because the generation of ROS is highly oxygen dependent. Recently reported hypoxia‐irrelevant radical initiators (AIBIs) exhibit promising potential for cancer therapy under different oxygen tensions. However, overexpressed glutathione (GSH) in cancer cells would potently scavenge the free radicals produced from AIBI before their arrival to the specific site and dramatically limit the therapeutic efficacy. A synergistic antitumor platform (MoS₂@AIBI‐PCM nanoflowers) is constructed by incorporating polyethylene‐glycol‐functionalized molybdenum disulfide (PEG‐MoS₂) nanoflowers with azo initiator and phase‐change material (PCM). Under near‐infrared laser (NIR) irradiation, the photothermal feature of PEG‐MoS₂ induces the decomposition of AIBI to produce free radicals. Furthermore, PEG‐MoS₂ can facilitate GSH oxidation without releasing toxic metal ions, greatly promoting tumor apoptosis and avoiding the introduction of toxic metal ions. This is the first example of the use of intelligent MoS₂‐based nanoflowers as a benign GSH scavenger for enhanced cancer treatment.     

Fuel‐Free Synthetic Micro‐/Nanomachines

Inspired by the swimming of natural microorganisms, synthetic micro‐/nanomachines, which convert energy into movement, are able to mimic the function of these amazing natural systems and help humanity by completing environmental and biological tasks. While offering autonomous propulsion, conventional micro‐/nanomachines usually rely on the decomposition of external chemical fuels (e.g., H₂O₂), which greatly hinders their applications in biologically relevant media. Recent developments have resulted in various micro‐/nanomotors that can be powered by biocompatible fuels. Fuel‐free synthetic micro‐/nanomotors, which can move without external chemical fuels, represent another attractive solution for practical applications owing to their biocompatibility and sustainability. Here, recent developments on fuel‐free micro‐/nanomotors (powered by various external stimuli such as light, magnetic, electric, or ultrasonic fields) are summarized, ranging from fabrication to propulsion mechanisms. The applications of these fuel‐free micro‐/nanomotors are also discussed, including nanopatterning, targeted drug/gene delivery, cell manipulation, and precision nanosurgery. With continuous innovation, future autonomous, intelligent and multifunctional fuel‐free micro‐/nanomachines are expected to have a profound impact upon diverse biomedical applications, providing unlimited opportunities beyond one's imagination.     

Light‐Driven ZnO Brush‐Shaped Self‐Propelled Micromachines for Nitroaromatic Explosives Decomposition

Self‐propelled micromachines have recently attracted lots of attention for environmental remediation. Developing a large‐scale but template‐free fabrication of self‐propelled rod/tubular micro/nanomotors is very crucial but still challenging. Here, a new strategy based on vertically aligned ZnO arrays is employed for the large‐scale and template‐free fabrication of self‐propelled ZnO‐based micromotors with H₂O₂‐free light‐driven propulsion ability. Brush‐shaped ZnO‐based micromotors with different diameters and lengths are fully studied, which present a fast response to multicycles UV light on/off switches with different interval times (2/5 s) in pure water and slow directional motion in aqueous hydrogen peroxide solution in the absence of UV light. Light‐induced electrophoretic and self‐diffusiophoretic effects are responsible for these two different self‐motion behaviors under different conditions, respectively. In addition, the pH of the media and the presence of H₂O₂ show important effects on the motion behavior and microstructure of the ZnO‐based micromotors. Finally, these novel ZnO‐based brush‐shaped micromotors are demonstrated in a proof‐of‐concept study on nitroaromatic explosive degradation, i.e., picric acid. This work opens a completely new avenue for the template‐free fabrication of brush‐shaped light‐responsive micromotors on a large scale based on vertically aligned ZnO arrays.     

Rational Design of Multifunctional Fe@γ‐Fe2O3@H‐TiO2 Nanocomposites with Enhanced Magnetic and Photoconversion Effects for Wide Applications: From Photocatalysis to Imaging‐Guided Photothermal Cancer Therapy

Titanium dioxide (TiO₂) has been widely investigated and used in many areas due to its high refractive index and ultraviolet light absorption, but the lack of absorption in the visible–near infrared (Vis–NIR) region limits its application. Herein, multifunctional Fe@γ‐Fe₂O₃@H‐TiO₂ nanocomposites (NCs) with multilayer‐structure are synthesized by one‐step hydrogen reduction, which show remarkably improved magnetic and photoconversion effects as a promising generalists for photocatalysis, bioimaging, and photothermal therapy (PTT). Hydrogenation is used to turn white TiO₂ in to hydrogenated TiO₂ (H‐TiO₂), thus improving the absorption in the Vis–NIR region. Based on the excellent solar‐driven photocatalytic activities of the H‐TiO₂ shell, the Fe@γ‐Fe₂O₃ magnetic core is introduced to make it convenient for separating and recovering the catalytic agents. More importantly, Fe@γ‐Fe₂O₃@H‐TiO₂ NCs show enhanced photothermal conversion efficiency due to more circuit loops for electron transitions between H‐TiO₂ and γ‐Fe₂O₃, and the electronic structures of Fe@γ‐Fe₂O₃@H‐TiO₂ NCs are calculated using the Vienna ab initio simulation package based on the density functional theory to account for the results. The reported core–shell NCs can serve as an NIR‐responsive photothermal agent for magnetic‐targeted photothermal therapy and as a multimodal imaging probe for cancer including infrared photothermal imaging, magnetic resonance imaging, and photoacoustic imaging.     

Dual‐Peak Absorbing Semiconducting Copolymer Nanoparticles for First and Second Near‐Infrared Window Photothermal Therapy: A Comparative Study

Near‐infrared (NIR) light is widely used for noninvasive optical diagnosis and phototherapy. However, current research focuses on the first NIR window (NIR‐I, 650–950 nm), while the second NIR window (NIR‐II, 1000–1700 nm) is far less exploited. The development of the first organic photothermal nanoagent (SPN_I‐II) with dual‐peak absorption in both NIR windows and its utilization in photothermal therapy (PTT) are reported herein. Such a nanoagent comprises a semiconducting copolymer with two distinct segments that respectively and identically absorb NIR light at 808 and 1064 nm. With the photothermal conversion efficiency of 43.4% at 1064 nm generally higher than other inorganic nanomaterials, SPN_I‐II enables superior deep‐tissue heating at 1064 nm over that at 808 nm at their respective safety limits. Model deep‐tissue cancer PTT at a tissue depth of 5 mm validates the enhanced antitumor effect of SPN_I‐II when shifting laser irradiation from the NIR‐I to the NIR‐II window. The good biodistribution and facile synthesis of SPN_I‐II also allow it to be doped with an NIR dye for fluorescence‐imaging‐guided NIR‐II PTT through systemic administration. Thus, this study paves the way for the development of new polymeric nanomaterials to advance phototherapy.