Ultrasound-Chargeable Persistent Luminescence Nanoparticles to Generate Self-Propelled Motion and Photothermal/NO Therapy for Synergistic Tumor Treatment

Recent advances in the development of tumor microenvironment-activatable nanomotors for deep tumor penetration

Cancer represents a significant threat to human health, with the use of traditional chemotherapy drugs being limited by their harsh side effects. Tumor-targeted nanocarriers have emerged as a promising solution to this problem, as they can deliver drugs directly to the tumor site, improving drug effectiveness and reducing adverse effects. However, the efficacy of most nanomedicines is hindered by poor penetration into solid tumors. Nanomotors, capable of converting various forms of energy into mechanical energy for self-propelled movement, offer a potential solution for enhancing drug delivery to deep tumor regions. External force-driven nanomotors, such as those powered by magnetic fields or ultrasound, provide precise control but often necessitate bulky and costly external equipment. Bio-driven nanomotors, propelled by sperm, macrophages, or bacteria, utilize biological molecules for self-propulsion and are well-suited to the physiological environment. However, they are constrained by limited lifespan, inadequate speed, and potential immune responses. To address these issues, nanomotors have been engineered to propel themselves forward by catalyzing intrinsic "fuel" in the tumor microenvironment. This mechanism facilitates their penetration through biological barriers, allowing them to reach deep tumor regions for targeted drug delivery. In this regard, this article provides a review of tumor microenvironment-activatable nanomotors (fueled by hydrogen peroxide, urea, arginine), and discusses their prospects and challenges in clinical translation, aiming to offer new insights for safe, efficient, and precise treatment in cancer therapy.

Surface Engineering Enhances Vanadium Carbide MXene-Based Nanoplatform Triggered by NIR-II for Cancer Theranostics

Despite the advantages of high tissue penetration depth, selectivity, and non-invasiveness of photothermal therapy for cancer treatment, developing NIR-II photothermal agents with desirable photothermal performance and advanced theranostics ability remains a key challenge. Herein, a universal surface modification strategy is proposed to effectively improve the photothermal performance of vanadium carbide MXene nanosheets (L-V2C) with the removal of surface impurity ions and generation of mesopores. Subsequently, MnOx coating capable of T1-weighted magnetic resonance imaging can be in situ formed through surface redox reaction on L-V2C, and then, stable nanoplatforms (LVM-PEG) under physiological conditions can be obtained after further PEGylation. In the tumor microenvironment irradiated by NIR-II laser, multivalent Mn ions released from LVM-PEG, as a reversible electronic station, can consume the overexpression of glutathione and catalyze a Fenton-like reaction to produce ·OH, resulting in synchronous cellular oxidative damage. Efficient synergistic therapy promotes immunogenic cell death, improving tumor-related immune microenvironment and immunomodulation, and thus, LVM-PEG can demonstrate high accuracy and excellent anticancer efficiency guided by multimodal imaging. As a result, this study provides a new approach for the customization of 2D surface strategies and the study of synergistic therapy mechanisms, highlighting the application of MXene-based materials in the biomedical field.

Controlled Surface Textures of Elastomeric Polyurethane Janus Particles: A Comprehensive Review

Colloidal particle research has witnessed significant advancements in the past century, resulting in a plethora of studies, novel applications, and beneficial products. This review article presents a cost-effective and low-tech method for producing Janus elastomeric particles of varied geometries, including planar films, spherical particles, and cylindrical fibers, utilizing a single elastomeric material and easily accessible chemicals. Different surface textures are attained through strain application or solvent-induced swelling, featuring well-defined wavelengths ranging from sub-microns to millimeters and offering easy adjustability. Such versatility renders these particles potentially invaluable for medical applications, especially in bacterial adhesion studies. The coexistence of "young" regions (smooth, with a small surface area) and "old" regions (wrinkled, with a large surface area) within the same material opens up avenues for biomimetic materials endowed with additional functionalities; for example, a Janus micromanipulator where micro- or nano-sized objects are grasped and transported by an array of wrinkled particles, facilitating precise release at designated locations through wrinkle pattern adjustments. This article underscores the versatility and potential applications of Janus elastomeric particles while highlighting the intriguing prospects of biomimetic materials with controlled surface textures.

Current Developments in Emerging Lanthanide-Doped Persistent Luminescent Scintillators and Their Applications

Lanthanide-doped scintillators have the ability to convert the absorbed X-ray irradiation into ultraviolet (UV), visible (Vis), or near-infrared (NIR) light. Lanthanide-doped scintillators with excellent persistent luminescence (PersL) are emerging as a new class of PersL materials recently. They have attracted great attention due to their unique "self-luminescence" characteristic and potential applications. In this review, we comb through and focus on current developments of lanthanide-doped persistent luminescent scintillators (PersLSs), including their PersL mechanism, synthetic methods, tuning of PersL properties (e. g. emission wavelength, intensity, and duration time), as well as their promising applications (e. g. information storage, encryption, anti-counterfeiting, bio-imaging, and photodynamic therapy). We hope this review will provide valuable guidance for the future development of PersLSs.

Sunflower Pollen-Morphology Mimicked Spiky Zinc Nanomotors as a Photosensitizer for Killing Bacteria and Cancer Cells

Photosensitizing agents have received increased attention from the medical community, owing to their higher photothermal efficiency, induction of hyperthermia, and sustained delivery of bioactive molecules to their targets. Micro/nanorobots can be used as ideal photosensitizing agents by utilizing various physical stimuli for the targeted killing of pathogens (e.g., bacteria) and cancer cells. Herein, we report sunflower-pollen-inspired spiky zinc oxide (s-ZnO)-based nanorobots that effectively kill bacteria and cancer cells under near-infrared (NIR) light irradiation. The as-fabricated s-ZnO was modified with a catechol-containing photothermal agent, polydopamine (PDA), to improve its NIR-responsive properties, followed by the addition of antimicrobial (e.g., tetracycline/TCN) and anticancer (e.g., doxorubicin/DOX) drugs. The fabricated s-ZnO/PDA@Drug nanobots exhibited unique locomotory behavior with an average speed ranging from 13 to 14 μm/s under 2.0 W/cm2 NIR light irradiation. Moreover, the s-ZnO/PDA@TCN nanobots exhibited superior antibacterial activity against E. coli and S. epidermidis under NIR irradiation. The s-ZnO/PDA@DOX nanobots also displayed sufficient reactive oxygen species (ROS) amplification in B16F10 melanoma cells and induced apoptosis under NIR light, indicating their therapeutic efficacy. We hope the sunflower pollen-inspired s-ZnO nanorobots have tremendous potential in biomedical engineering from the phototherapy perspective, with the hope to reduce pathogen infections.

Black Titania Janus Mesoporous Nanomotor for Enhanced Tumor Penetration and Near-Infrared Light-Triggered Photodynamic Therapy

Thanks to their excellent photoelectric characteristics to generate cytotoxic reactive oxygen species (ROS) under the light-activation process, TiO2 nanomaterials have shown significant potential in photodynamic therapy (PDT) for solid tumors. Nevertheless, the limited penetration depth of TiO2-based photosensitizers and excitation sources (UV/visible light) for PDT remains a formidable challenge when confronted with complex tumor microenvironments (TMEs). Here, we present a H2O2-driven black TiO2 mesoporous nanomotor with near-infrared (NIR) light absorption capability and autonomous navigation ability, which effectively enhances solid tumor penetration in NIR light-triggered PDT. The nanomotor was rationally designed and fabricated based on the Janus mesoporous nanostructure, which consists of a NIR light-responsive black TiO2 nanosphere and an enzyme-modified periodic mesoporous organosilica (PMO) nanorod that wraps around the TiO2 nanosphere. The overexpressed H2O2 can drive the nanomotor in the TME under catalysis of catalase in the PMO domain. By precisely controlling the ratio of TiO2 and PMO compartments in the Janus nanostructure, TiO2&PMO nanomotors can achieve optimal self-propulsive directionality and velocity, enhancing cellular uptake and facilitating deep tumor penetration. Additionally, by the decomposition of endogenous H2O2 within solid tumors, these nanomotors can continuously supply oxygen to enable highly efficient ROS production under the NIR photocatalysis of black TiO2, leading to intensified PDT effects and effective tumor inhibition.

Nanomaterials for light-mediated therapeutics in deep tissue

Light-mediated therapeutics, including photodynamic therapy, photothermal therapy and light-triggered drug delivery, have been widely studied due to their high specificity and effective therapy. However, conventional light-mediated therapies usually depend on the activation of light-sensitive molecules with UV or visible light, which have poor penetration in biological tissues. Over the past decade, efforts have been made to engineer nanosystems that can generate luminescence through excitation with near-infrared (NIR) light, ultrasound or X-ray. Certain nanosystems can even carry out light-mediated therapy through chemiluminescence, eliminating the need for external activation. Compared to UV or visible light, these 4 excitation modes penetrate more deeply into biological tissues, triggering light-mediated therapy in deeper tissues. In this review, we systematically report the design and mechanisms of different luminescent nanosystems excited by the 4 excitation sources, methods to enhance the generated luminescence, and recent applications of such nanosystems in deep tissue light-mediated therapeutics.

Amphiphilic Janus nanoparticles for nitric oxide synergistic photodynamic eradication of MRSA biofilms

Biofilms pose significant threats to public health by causing persistent clinical infections. The development of innovative antibacterial approaches for eliminating biofilms is an urgent necessity. In this study, we developed amphiphilic Janus nanoparticles (JNPs), loaded with hydrophobic chlorin e6 (Ce6) and hydrophilic S-nitrosoglutathione (GSNO), denoted as Ce6-PDA/CaP-GSNO, with the aim to effectively eradicate biofilms and combat methicillin-resistant Staphylococcus aureus (MRSA) infections through nitric oxide (NO) synergistic photodynamic therapy (PDT). Ce6-PDA/CaP-GSNO demonstrated remarkable biofilm penetration ability, efficiently reaching the acidic inner layers, which triggered the rapid release of GSNO, resulting in the generation of an abundant supply of NO. NO not only exhibited potent bactericidal activity but also effectively lowered the GSH level of the biofilm, leading to enhanced efficacy of Ce6. Additionally, the interaction between NO and reactive oxygen species (ROS) resulted in the generation of reactive nitrogen species (RNS), further enhancing PDT efficacy both in vitro and in vivo. In summary, Ce6-PDA/CaP-GSNO demonstrated remarkable biofilm penetration capacity and effective reduction of the GSH level in the biofilms, leading to enhanced PDT efficacy at low photosensitizer doses and laser intensities, thereby minimizing adverse effects on normal tissues. These findings highlight the promising potential of our approach for combating biofilm-related infections.

Photothermal-driven micro/nanomotors: From structural design to potential applications

Micro/nanomotors (MNMs) that accomplish autonomous movement by transforming external energy into mechanical work are attractive cargo delivery vehicles. Among various propulsion mechanisms of MNMs, photothermal propulsion has gained considerable attention because of their unique advantages, such as remote, flexible, accurate, biocompatible, short response time, etc. Moreover, besides as a propulsion source, the light has been extensively investigated as an excitation source in bioimaging, photothermal therapy (PTT), photodynamic therapy (PDT) and so on. Furthermore, the geometric topology and morphology of MNMs have a tremendous impact on improving their performance in motion behavior under NIR light propulsion, environmental suitability and functional versatility. Hence, this review article provides a comprehensive overview of structural design principles and construction strategies of photothermal-driven MNMs, and their emerging nanobiomedical applications. Finally, we further provide an outlook towards prospects and challenges during the development of photothermal-driven MNMs in the future. STATEMENT OF SIGNIFICANCE: Photothermal-driven micro/nanomotors (MNMs) that are regarded as functional cargo delivery tools have gained considerable attention because of unique advantages in propulsion mechanisms, such as remote, flexible, accurate and fully biocompatible light manipulation and extremely short light response time. The geometric topology and morphology of MNMs have a tremendous impact on improving their performance in motion behavior under NIR light propulsion, environmental suitability and functional versatility of MNMs. There are no reports about the review focusing on photothermal-driven MNMs up to now. Herein, we systematically review the latest progress of photothermal-driven MNMs including design principle, fabrication strategy of various MNMs with different structures and nanobiomedical applications. Moreover, the summary and outlook on the development prospects and challenges of photothermal-driven MNMs are proposed, hoping to provide new ideas for the future design of photothermal-driven MNMs with efficient propulsion, multiple functions and high biocompatibility.