Tantalum Sulfide Nanosheets as a Theranostic Nanoplatform for Computed Tomography Imaging-Guided Combinatorial Chemo-Photothermal Therapy

Advanced antibacterial activity of biocompatible tantalum nanofilm via enhanced local innate immunity

Tantalum (Ta) has been shown to enhance osseointegration in clinical practice, yet little is known about whether Ta nanofilms can be used as antimicrobial coatings in vivo. A highly biocompatible Ta nanofilm was developed using magnetron sputtering technology to further study the mechanism of its antibacterial effects in vivo and elucidate its potential for clinical translation. The Ta nanofilms exhibited effective antimicrobial activity against soft tissue infections but did not show an intrinsic antimicrobial effect in vitro. This inconsistency between the in vivo and in vitro antimicrobial effects was further investigated using ex vivo models. The Ta nanofilms could enhance the phagocytosis of bacteria by polymorphonuclear neutrophils (PMNs, neutrophils), reduce the lysis of neutrophils and enhance the proinflammatory cytokine release of macrophages. This accumulative enhancement of the local host defenses contributed to the favorable antibacterial effect in vivo. The alleviated osteolysis observed in the presence of the Ta nanofilms in the osteomyelitis model further proved the practicality of this antibacterial strategy in the orthopedic field. In summary, Ta nanofilms show excellent biocompatibility and in vivo antimicrobial activity mediated by the enhancement of local innate immunity and are promising for clinical application. STATEMENT OF SIGNIFICANCE: In this study, Ta nanofilms were deposited on titanium substrate by magnetron sputtering. Ta nanofilms exhibited excellent in vivo and in vitro biocompatibility. In vivo antimicrobial effects of Ta nanofilms were revealed by soft tissue infection and osteomyelitis models, while no direct antibacterial activity was observed in vitro. Comprehensive ex vivo models revealed that Ta nanofilms could enhance the phagocytosis of bacteria by neutrophils, reduce the lysis of neutrophils and promote the release of proinflammatory cytokines from macrophages. This immunomodulatory effect helps host to eliminate bacteria. In contrast to traditional antimicrobial nanocoatings which apply toxic materials to kill bacteria, this work proposes a safe, practical and effective Ta nanofilm immunomodulatory antimicrobial strategy with clinical translational prospect.

Functional black phosphorus nanosheets for mitochondria-targeting photothermal/photodynamic synergistic cancer therapy

A mitochondria-targeting nanosystem, BP@PDA–Ce6&TPP NSs, has been constructed, and exhibit excellent performance in imaging-guided synergistic photothermal and photodynamic cancer therapy.

Organelle-targeting nanosystems are envisioned as promising tools for phototherapy, which can generate heat or reactive oxygen species (ROS) induced cytotoxicity in the targeted location but leave the surrounding biological tissues undamaged. In this work, an imaging-guided mitochondria-targeting photothermal/photodynamic nanosystem has been developed on the basis of functionalized black phosphorus (BP) nanosheets (NSs). In the nanosystem, BP NSs are coated with polydopamine (PDA) and then covalently linked with both chlorin e6 (Ce6) and triphenyl phosphonium (TPP) through carbodiimide reaction between the amino group and the carboxyl group, forming BP@PDA–Ce6&TPP NSs. Due to the strong absorbance of BP@PDA in the near-infrared region and the highly efficient ROS generation of Ce6, the as-prepared nanosystem with mitochondria-targeting capacity (TPP moiety) shows remarkably enhanced efficiency in cancer cell killing. Combined photothermal and photodynamic therapy is implemented and monitored by in vivo fluorescence imaging, achieving excellent performance in inhibiting tumor growth. This study presents a novel nanotheranostic agent for mitochondria-targeting phototherapy, which may open new horizons for biomedicine.

Ultrathin Tellurium Oxide/Ammonium Tungsten Bronze Nanoribbon for Multimodality Imaging and Second Near-Infrared Region Photothermal Therapy

Developing nanophotothermal agents (PTAs) with satisfied photothermal conversion efficiency (PTCE) in the second NIR window (1000-1350 nm, NIR II) holds great promise for enhanced photothermal therapy effect. Herein, we develop a NIR-II PTA with advanced PTCE, based on a new two-dimensional ultrathin tellurium oxide/ammonium tungsten bronze (TeO₂/(NH₄) _xWO₃) nanoribbons (TONW NRs). The doped ammonia ions-mediated-free-electrons injection into the lowest unoccupied molecular orbital band of WO₃ combined with the electronic transitions between W⁶⁺ ions and the lone pair of electrons in Te atoms achieve excellent NIR absorption of TONW NRs resulting from localized surface plasmon resonance. The polyethylene glycol functionalized TONW NRs (PEG-TONW NRs) exhibit good stability and biocompatibility, displaying a PTCE high to 43.6%, surpassing many previous nano-PTAs active in the NIR II region, leading to remarkable tumor ablation ability both in vitro and in vivo. Meanwhile, advanced X-ray computed tomography (CT) and photoacoustic (PA) imaging capability of PEG-TONW NRs were also realized. Given the admirable photothermal effect in NIR II region, good biocompatibility, and advanced CT/PA imaging diagnosis capability, the novel PEG-TONW NRs is promising in future personalized medicine applications.

Recent advances of stimuli-responsive systems based on transition metal dichalcogenides for smart cancer therapy

A comprehensive overview of the development of stimuli-responsive TMDC-based nanoplatforms for “smart” cancer therapy is presented to demonstrate a more intelligent and better controllable therapeutic strategy.

NIR light-responsive short peptide/2D NbSe2 nanosheets composite hydrogel with controlled-release capacity

The design of light-responsive peptide hydrogels with controllable drug release characteristics is still a challenge.

Cu-Fe-Se Ternary Nanosheet-Based Drug Delivery Carrier for Multimodal Imaging and Combined Chemo/Photothermal Therapy of Cancer

Ternary transition-metal chalcogenide nanosheets have shown great potential in diverse applications owing to their intrinsically amazing properties with a broad tunable window. Direct preparation of water-soluble and biocompatible ternary chalcogenide nanosheets for theranostic application remains a challenge. In this article, we prepared Cu-Fe-Se nanosheets (CFS NSs) in an aqueous solution under ambient conditions by a sequential coprecipitation method. They were functionalized with anticancer drug doxorubin (CFS@DOX) through electrostatic interactions and labeled with radioactive isotope ^99mTc through surface coordination effect. The resulting nanosheets have a size of 70 nm and a thickness of 5 nm, and can be well dispersed in water, phosphate-buffered saline, 10% fetal bovine serum, and 0.9% NaCl with an excellent colloidal stability. They also exhibit a high photothermal conversion efficiency of 78.9% for in vitro and in vivo photoacoustic imaging and photothermal therapy. The isotope-labeled nanosheets (^99mTc-CFS NSs) were used for single photon emission computed tomography/computed tomography imaging to quantify their blood circulation time (∼4.7 h) and biodistributions in major organs, which follow an order of liver > bladder > lung > spleen > heart > kidney. The DOX-functionalized nanosheets (CFS@DOX) were used for chemotherapy of cancer and exhibited excellent anticancer efficacy. Our research shows the great promise of ternary metal chalcogenide nanosheets for combined imaging and therapy of cancer.

A NanoFlare-Based Strategy for In Situ Tumor Margin Demarcation and Neoadjuvant Gene/Photothermal Therapy

Accurate tumor margin demarcation in situ remains a paramount challenge. Herein, a NanoFlare (also known as spherical-nucleic-acid technology) based strategy is reported for in situ tumor margin delineation by transforming and amplifying the pathophysiological redox signals of tumor microenvironment. The NanoFlare designed (named AuNS-ASON) is based on gold nanostar (AuNS) coated with a dense shell of disulfide bridge-inserted and cyanine dyes-labeled antisense oligonucleotides (ASON) targeting survivin mRNA. The unique anisotropic ASON-spike nanostructure endows the AuNS-ASON with universal cellular internalization of tumor cells, while the disulfide bridge inserted confers response specificity toward redox activation. In vitro experiments demonstrate that the AuNS-ASON can discriminate tumor cells rapidly with activated fluorescence signals (>100-fold) in 2 h, and further achieve synergistic gene/photothermal tumor cells ablation upon near-infrared laser irradiation. Remarkably, in situ tumor margin delineation with high accuracy and outstanding spatial resolution (<100 µm) in mice bearing different tumors is obtained based on the AuNS-ASON, providing intraoperative guidance for tumor resection. Moreover, the AuNS-ASON can enable efficient neoadjuvant gene/photothermal therapy before surgery to reduce tumor extent and increase resectability. The concept of NanoFlare-based microenvironment signal transformation and amplification could be used as a general strategy to guide the design of activatable nanoprobes for cancer theranostics.

Remote-Controlling Potassium Channels in Living Cells through Photothermal Inactivation of Calmodulin

Spatiotemporal regulation of cellular functions provides a powerful strategy for understanding underlying mechanisms of cellular bioprocesses. Here, a strategy is reported to realize the remote control of the activities of potassium channels via photothermal inactivation of calmodulin (CaM) by using reduced graphene oxide decorated with calmodulin binding peptide (rGO-P) as the transducer with near-infrared light (NIR) irradiation. Upon NIR light irradiation, the CaM/Ca²⁺ bound to rGO-P is inactivated by the photothermal effect of rGO-P, resulting in the incapability of binding with Ca²⁺ . Hence, the closed Kv10.1 channel is converted to be open in the presence of calcium in living cells. Meanwhile, the SK2 channel is induced to be closed from the open state and the Kir2.1 channel is unaffected by the intracellular inactivation of CaM. This strategy gives a noninvasive and effective approach to remotely control the activities of potassium channels, offering an alternative for the development of optogenetics.

Near-Infrared II Dye-Protein Complex for Biomedical Imaging and Imaging-Guided Photothermal Therapy

The development of novel biodegradable and nontoxic fluorophores that integrate diagnosis and therapy for effective cancer treatment has obtained tremendous attention in the past decades. In this report, water-soluble and biocompatible small-molecule near-infrared II (NIR-II) fluorescent dye H2a-4T complexed with fetal bovine serum (FBS) and Cetuximab proteins with excellent optical properties and targeting ability is prepared. High spatial and temporal resolution imaging of hind limb vasculature and the lymphatic system of living mice using H2a-4T@FBS complex is demonstrated in precise NIR-II imaging-guided sentinel lymph node surgery. More importantly, H2a-4T@Cetuximab complex not only exhibits a remarkable cell-killing ability but also achieves highly active tumor targeting efficiency for epidermal growth factor receptor, overexpressing colorectal cancer which is beneficial to in vivo NIR-II fluorescent imaging-guided photothermal therapy of colon tumors. To the best of our knowledge, it is the first time that the concept of light-harvesting complex is exploited for enhancing the NIR-II signals and photothermal energy conversion in molecule-protein complex theranostic agent, making them a promising candidate for future clinical applications in cancer theranostics.

Hypoxia-Triggered Nanoscale Metal-Organic Frameworks for Enhanced Anticancer Activity

The oxygen-dependent feature of most photosensitizers (PSs) and the aggravated hypoxia tumor microenvironment seriously impede the photodynamic therapy (PDT) effectiveness. However, this undesirable impediment can be utilized to further trigger the activation of hypoxia-sensitive prodrugs. Moreover, a combined therapy can be used by associating PDT with hypoxia-activated chemotherapy. Herein, a multifunctional Hf-porphyrin nanoscale metal-organic framework (NMOF) platform [Hf/tetra(4-carboxyphenyl)porphine (TCPP)] has been synthesized, with a high porphyrin loading capacity and a well-ordered coordination array preventing porphyrin self-quenching, thus greatly improving the generation efficiency of reactive oxygen species (ROS), which is helpful for PDT. As-synthesized Hf-TCPP nanoparticles possess more than 50 wt % of TCPP PS content, good crystallization, and a large Brunauer-Emmett-Teller surface for further loading the hypoxia-activated prodrug [tirapazamine (TPZ)] in a high-loading content. Additionally, subsequent surface modification with a dopamine-derived polymer (DOPA-PIMA-mPEG) significantly improves their dispersibility and structural stability, and the controlled release kinetics of TPZ. Such a nanoplatform can efficiently produce ROS for PDT upon irradiation, and also the depletion of the oxygen could further aggravate the hypoxic environment of tumors to induce the activation of TPZ for achieving an enhanced treatment efficacy. This work demonstrates the great advantages of an NMOF-based platform in antitumor therapies for combined PDT and hypoxia-activated chemotherapy.

A Novel Top-Down Synthesis of Ultrathin 2D Boron Nanosheets for Multimodal Imaging-Guided Cancer Therapy

Single atom nonmetal 2D nanomaterials have shown considerable potential in cancer nanomedicines, owing to their intriguing properties and biocompatibility. Herein, ultrathin boron nanosheets (B NSs) are prepared through a novel top-down approach by coupling thermal oxidation etching and liquid exfoliation technologies, with controlled nanoscale thickness. Based on the PEGylated B NSs, a new photonic drug delivery platform is developed, which exhibits multiple promising features for cancer therapy and imaging, including: i) efficient NIR-light-to-heat conversion with a high photothermal conversion efficiency of 42.5%, ii) high drug-loading capacity and triggered drug release by NIR light and moderate acidic pH, iii) strong accumulation at tumor sites, iv) multimodal imaging properties (photoacoustic, photothermal, and fluorescence imaging), and v) complete tumor ablation and excellent biocompatibility. As far as it is known, this is the first report on the top-down fabrication of ultrathin 2D B NSs by the combined thermal oxidation etching and liquid exfoliation, as well as their application as a multimodal imaging-guided drug delivery platform. The newly prepared B NSs are also expected to provide a robust and useful 2D nanoplatform for various biomedical applications.

An easy-to-fabricate clearable CuS-superstructure-based multifunctional theranostic platform for efficient imaging guided chemo-photothermal therapy

Despite drug delivery systems (DDSs) receiving ever-increasing attention, development of a simple, effective, sensitive and clearable drug delivery and multifunctional theranostic nanoplatform for cancer therapy is still highly desirable and remains a challenge. Herein, using a one-step solvothermal method, hollow acanthosphere-like CuS superstructures assembled from ∼10 nm nanoparticles (NPs) were successfully obtained and used as an efficient drug delivery and theranostic platform for photoacoustic (PA) and infrared (IR) thermal imaging-guided cancer combination therapy. The special hollow characteristic of CuS superstructures with mesoporous shells and large cavities grants them high drug loading capacity; they demonstrate near-infrared (NIR)/pH stimuli-sensitive drug release and pronounced synergetic effects of chemo-photothermal therapy both in vitro and in vivo. In particular, our as-fabricated hollow loose CuS superstructures, with easily breakable characteristic, are biodegradable and able to be cleared from the body when their therapy task is completed. This CuS-superstructure-based clearable drug delivery and "all-in-one" cancer theranostic platform might provide possibilities for improving therapeutic efficacy and minimizing adverse effects.

Liquid Exfoliation of Colloidal Rhenium Disulfide Nanosheets as a Multifunctional Theranostic Agent for In Vivo Photoacoustic/CT Imaging and Photothermal Therapy

Near-infrared light-mediated theranostic agents with superior tissue penetration and minimal invasion have captivated researchers in cancer research in the past decade. Herein, a probe sonication-assisted liquid exfoliation approach for scalable and continual synthesis of colloidal rhenium disulfide nanosheets, which is further explored as theranostic agents for cancer diagnosis and therapy, is reported. Due to high-Z element of Re (Z = 75) and significant photoacoustic effect, the obtained PVP-capped ReS₂ nanosheets are evaluated as bimodality contrast agents for computed tomography and photoacoustic imaging. In addition, utilizing the strong near-infrared absorption and ultrahigh photothermal conversion efficiency (79.2%), ReS₂ nanosheets could also serve as therapeutic agents for photothermal ablation of tumors with a tumor elimination rate up to 100%. Importantly, ReS₂ nanosheets show no obvious toxicity based on the cytotoxicity assay, serum biochemistry, and histological analysis. This work highlights the potentials of ReS₂ nanosheets as a single-component theranostic nanoplatform for bioimaging and antitumor therapy.

Sequential delivery of bismuth nanoparticles and doxorubicin by injectable macroporous hydrogels for combined anticancer kilovoltage X-ray radio- and chemo-therapy

Sequential delivery systems are required to maximize synergistic anticancer therapeutic effects in combined X-ray radio- and chemo-therapy.