Highly efficient ablation of metastatic breast cancer using ammonium-tungsten-bronze nanocube as a novel 1064 nm-laser-driven photothermal agent

Photocrosslinked Co-Assembled Amino Acid Nanoparticles for Controlled Chemo/Photothermal Combined Anticancer Therapy

Nanostructures formed from the self-assembly of amino acids are promising materials in many fields, especially for biomedical applications. However, their low stability resulting from the weak noncovalent interactions between the amino acid building blocks limits their use. In this work, nanoparticles co-assembled by fluorenylmethoxycarbonyl (Fmoc)-protected tyrosine (Fmoc-Tyr-OH) and tryptophan (Fmoc-Trp-OH) are crosslinked by ultraviolet (UV) light irradiation. Two methods are investigated to induce the dimerization of tyrosine, irradiating at 254 nm or at 365 nm in the presence of riboflavin as a photo-initiator. For the crosslinking performed at 254 nm, both Fmoc-Tyr-OH and Fmoc-Trp-OH generate dimers. In contrast, only Fmoc-Tyr-OH participates in the riboflavin-mediated dimerization under irradiation at 365 nm. The participation of both amino acids in forming the dimers leads to more stable crosslinked nanoparticles, allowing also to perform further chemical modifications for cancer applications. The anticancer drug doxorubicin (Dox) is adsorbed onto the crosslinked nanoparticles, subsequently coated by a tannic acid-iron complex, endowing the nanoparticles with glutathione-responsiveness and photothermal properties, allowing to control the release of Dox. A remarkable anticancer efficiency is obtained in vitro and in vivo in tumor-bearing mice thanks to the combined chemo- and photothermal treatment.

A Nanographene-Porphyrin Hybrid for Near-Infrared-Ii Phototheranostics

Photoacoustic imaging (PAI)-guided photothermal therapy (PTT) in the second near-infrared (NIR-II, 1000-1700 nm) window has been attracting attention as a promising cancer theranostic platform. Here, it is reported that the π-extended porphyrins fused with one or two nanographene units (NGP-1 and NGP-2) can serve as a new class of NIR-responsive organic agents, displaying absorption extending to ≈1000 and ≈1400 nm in the NIR-I and NIR-II windows, respectively. NGP-1 and NGP-2 are dispersed in water through encapsulation into self-assembled nanoparticles (NPs), achieving high photothermal conversion efficiency of 60% and 69%, respectively, under 808 and 1064 nm laser irradiation. Moreover, the NIR-II-active NGP-2-NPs demonstrated promising photoacoustic responses, along with high photostability and biocompatibility, enabling PAI and efficient NIR-II PTT of cancer in vivo.

Fused Azulenyl Squaraine Derivatives Improve Phototheranostics in the Second Near-Infrared Window by Concentrating Excited State Energy on Non-Radiative Decay Pathways

The second near-infrared (NIR-II) theranostics offer new opportunities for precise disease phototheranostic due to the enhanced tissue penetration and higher maximum permissible exposure of NIR-II light. However, traditional regimens lacking effective NIR-II absorption and uncontrollable excited-state energy decay pathways often result in insufficient theranostic outcomes. Herein a phototheranostic nano-agent (PS-1 NPs) based on azulenyl squaraine derivatives with a strong NIR-II absorption band centered at 1092 nm is reported, allowing almost all absorbed excitation energy to dissipate through non-radiative decay pathways, leading to high photothermal conversion efficiency (90.98 %) and strong photoacoustic response. Both in vitro and in vivo photoacoustic/photothermal therapy results demonstrate enhanced deep tissue cancer theranostic performance of PS-1 NPs. Even in the 5 mm deep-seated tumor model, PS-1 NPs demonstrated a satisfactory anti-tumor effect in photoacoustic imaging-guided photothermal therapy. Moreover, for the human extracted tooth root canal infection model, the synergistic outcomes of the photothermal effect of PS-1 NPs and 0.5 % NaClO solution resulted in therapeutic efficacy comparable to the clinical gold standard irrigation agent 5.25 % NaClO, opening up possibilities for the expansion of NIR-II theranostic agents in oral medicine.

A Laser-Driven Microrobot for Thermal Stimulation of Single Cells

Here, the study presents a thermally activated cell-signal imaging (TACSI) microrobot, capable of photothermal actuation, sensing, and light-driven locomotion. The plasmonic soft microrobot is specifically designed for thermal stimulation of mammalian cells to investigate cell behavior under heat active conditions. Due to the integrated thermosensitive fluorescence probe, Rhodamine B, the system allows dynamic measurement of induced temperature changes. TACSI microrobots show excellent biocompatibility over 72 h in vitro, and they are capable of thermally activating single cells to cell clusters. Locomotion in a 3D workspace is achieved by relying on thermophoretic convection, and the microrobot speed is controlled within a range of 5-65 µm s-1 . In addition, light-driven actuation enables spatiotemporal control of the microrobot temperature up to a maximum of 60 °C. Using TACSI microrobots, this study targets single cells within a large population, and demonstrates thermal cell stimulation using calcium signaling as a biological output. Initial studies with human embryonic kidney 293 cells indicate a dose dependent change in intracellular calcium content within the photothermally controlled temperature range of 37-57 °C.

Investigations of the Photothermal Properties of a Series of Molecular Gold-bis(dithiolene) Complexes Absorbing in the NIR-III Region

The photothermal properties of a series of neutral radical gold-bis(dithiolene) complexes absorbing in the near-infrared-III window (1550-1870 nm) have been investigated. This class of complexes was found to be good photothermal agents (PTAs) in toluene under 1600 nm laser irradiation with photothermal efficiencies around 40 and 60 % depending on the nature of the dithiolene ligand. To the best of our knowledge, these complexes are the first small molecular photothermal agents to absorb so far into the near infrared. To test their applicability in water, these hydrophobic complexes have been encapsulated into nanoparticles constituted by amphiphilic block-copolymers. Stable suspensions of polymeric nanoparticles (NPs) encapsulating the gold-bis(dithiolene) complexes have been prepared which show a diameter around 100 nm. The encapsulation rate was found to be strongly dependent on the nature of the dithiolene ligands. The photothermal properties of the aqueous suspensions containing gold-bis(dithiolene) complexes were then studied under 1600 nm laser irradiation. These studies demonstrate that water has strong photothermal activity in the NIR-III region that, cannot be overcome even with the addition of gold complexes displaying good photothermal properties.

Tungsten-based Nanomaterials in the Biomedical Field: A Bibliometric Analysis of Research Progress and Prospects

Tungsten-based nanomaterials (TNMs) with diverse nanostructures and unique physicochemical properties have been widely applied in the biomedical field. Although various reviews have described the application of TNMs in specific biomedical fields, there are still no comprehensive studies that summarize and analyze research trends of the field as a whole. To identify and further promote the development of biomedical TNMs, a bibliometric analysis method is used to analyze all relevant literature on this topic. First, general bibliometric distributions of the dataset by year, country, institute, referenced source, and research hotspots are recognized. Next, a comprehensive review of the subjectively recognized research hotspots in various biomedical fields, including biological sensing, anticancer treatments, antibacterials, and toxicity evaluation, is provided. Finally, the prospects and challenges of TNMs are discussed to provide a new perspective for further promoting their development in biomedical research.

A synergistic chemodynamic-photodynamic-photothermal therapy platform based on biodegradable Ce-doped MoOx nanoparticles

Near-infrared light-induced catalysts are considered to be potential nanoagents for tumor therapy. Cerium (Ce) is a non-biotoxic lanthanide element and exhibits variable valence states for catalytic reactions. In this work, we report a one-step hydrothermal synthesis for Ce-doped MoO_x (CMO) nanomaterials. The obtained CMO nanomaterials show high absorption in the NIR II regime and a high photothermal conversion efficiency of 67.7% (1064 nm). Moreover, due to the doping of Ce element, the consumption of hydrogen peroxide (H₂O₂) and glutathione (GSH) is boosted which enhances the chemodynamic and photodynamic therapy simultaneously. Under NIR II laser irradiation, the designed CMO nanocatalysts induce metabolism disruption and mitochondrial damage in the tumor cells. As-prepared CMO nanomaterials also show good biocompatibility and pH-responsive degradation behavior, which can be degraded rapidly under alkaline conditions (pH = 7.4) and remain stable in acidic solution (pH = 5.6). These properties make CMO nanomaterials ideal biodegradable nanotheranostic agents for synergistic chemodynamic-photodynamic-photothermal antitumor therapy.

Recent advances in photothermal therapy-based multifunctional nanoplatforms for breast cancer

Breast cancer (BC) is one of the most common cancers in women worldwide; however, the successful treatment of BC, especially triple-negative breast cancer (TNBC), remains a significant clinical challenge. Recently, photothermal therapy (PTT), which involves the generation of heat under irradiation to achieve photothermal ablation of BC with minimal invasiveness and outstanding spatial–temporal selectivity, has been demonstrated as a novel therapy that can overcome the drawbacks of chemotherapy or surgery. Significantly, when combining PTT with chemotherapy and/or photodynamic therapy, an enhanced synergistic therapeutic effect can be achieved in both primary and metastatic BC tumors. Thus, this review discusses the recent developments in nanotechnology-based photothermal therapy for the treatment of BC and its metastasis to provide potential strategies for future BC treatment.

A Cu-based nanoplatform for near-infrared light amplified multi-mode prostate cancer specific therapy

Chemodynamic therapy (CDT), as a new method for oncotherapy, can convert less reactive hydrogen peroxide (H₂O₂) into highly toxic hydroxyl radicals (˙OH) in the tumor microenvironment (TME) to kill tumor cells and inhibit tumor growth. However, the TME usually presents a low content of endogenous H₂O₂ and weak acidity, which weakens the therapeutic effect of CDT to a certain extent. Here, we developed a multifunctional nanoplatform based on Cu-doped mesoporous carbon nanospheres loaded with free radical generator 2'-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride (AIPH) and polyacrylic acid (Cu-MNCS-AIPH@PAA). Cu-MNCS-AIPH@PAA exhibited high photothermal conversion efficiency, and could not only act as a good photothermal agent for photothermal therapy (PTT) but also trigger AIPH to produce alkyl radicals. In response to the specificity of the TME, Cu-MNCS-AIPH@PAA could generate ˙OH through a Fenton-like reaction for CDT and enhance the efficacy of CDT by a photothermal effect. The excellent anticancer efficiency by the synergistic effect of CDT, PTT and free radicals, high biocompatibility and low adverse effects of Cu-MNCS-AIPH@PAA make it an ideal nanoplatform for tumor therapy.

A biotin-modified and H2O2-activatable theranostic nanoplatform for enhanced photothermal and chemical combination cancer therapy

Although synergistic effects of photothermal therapy (PTT) and chemotherapy for cancer have been extensively investigated in previous studies, more potential strategies need to be exploited to alleviate severe adverse effects. In this study, a biotin-modified and activatable nanotheranostic system is developed. This system (BPSP/DOX-CyBA) composed of H₂O₂-sensitive thioketal (TK) linker, hydrophilic biotin-decorated polyethylene glycol (PEG) segment, hydrophobic polycaprolactone (PCL) segment, could self-assemble into (99±1.3) nm nanoparticles and co-deliver H₂O₂-triggered photosensitizer CyBA and cytotoxic drugs DOX to tumor site. In vitro, DOX and CyBA could release rapidly from nanoparticles, CyBA accumulation in the mitochondria causes mitochondrial damage, leading to mitochondrial dysfunctions,while rising the level of ROS in B16F10 cells, and further to promote the micells to trigger release. CyBA could be activated into CyOH and the photothermal therapy was turn "off" into "on". In BPSP/DOX-CyBA group, the local temperature within tumor reached 50℃ and cell apoptosis rate reached 68.6% under Laser irradiation(650 nm, 1W/cm2). Fluorescence microscopy and flow cytometry analysis further demonstrated the better uptake efficiency on B16F10 cells with biotin decoration. In a mice B16F10 tumor model, the group with co-delivery CyBA and DOX had the best tumor retention effect, the maximal local temperature increasement and the minimum tumor growth with negligible side effects, suggesting the potential of BPSP/DOX-CyBA nanopalteform that synergistic photothermal therapy and chemotherapy and mitochondria damage as an effective melanoma treatment strategy.

Recent Advances in Engineering Nanomedicines for Second Near-Infrared Photothermal-Combinational Immunotherapy

Immunotherapy has emerged as one of the major strategies for cancer treatment. Unlike conventional therapeutic methods, immunotherapy can treat both primary and distant metastatic tumors through triggering systematic antitumor immune responses and can even prevent tumor recurrence after causing the formation of immune memory. However, immunotherapy still has the issues of low patient response rates and severe immune-related adverse events in clinical practices. In this regard, the combination of nanomedicine-mediated therapy with immunotherapy can modulate a tumor immunosuppressive microenvironment and thus amplify antitumor immunity. In particular, second near-infrared (NIR-II) photothermal therapy (PTT), which utilizes light conversions to generate heat for killing cancer cells, has shown unique advantages in combining with immunotherapy. In this review, the recent progress of engineering nanomedicines for NIR-II PTT combinational immunotherapy is summarized. The role of nanomedicine-mediated NIR-II PTT in inducing immunogenic cell death and reprogramming the tumor immunosuppressive microenvironment for facilitating immunotherapy are highlighted. The development of NIR-II-absorbing organic and inorganic nonmetal and inorganic metal nanomedicines for the NIR-II PTT combinational immunotherapy of cancer is also introduced in detail. Lastly, the current challenges and future perspectives of these nanomedicines for combinational immunotherapy are proposed.

LncRNA GACAT3: A Promising Biomarker and Therapeutic Target in Human Cancers

Long non-coding RNAs (lncRNAs) are a class of functional RNA molecules that do not encode proteins and are composed of more than 200 nucleotides. LncRNAs play important roles in epigenetic and gene expression regulation. The oncogenic lncRNA GACAT3 was recently discovered to be dysregulated in many tumors. Aberrant expression of GACAT3 contributes to clinical characteristics and regulates multiple oncogenic processes. The association of GACAT3 with a variety of tumors makes it a promising biomarker for diagnosis, prognosis, and targeted therapy. In this review, we integrate the current understanding of the pathological features, biological functions, and molecular mechanisms of GACAT3 in cancer. Additionally, we provide insight into the utility of GACAT3 as an effective diagnostic and prognostic marker for specific tumors, which offers novel opportunities for targeted therapeutic intervention.

Recent advances in selective photothermal therapy of tumor

Photothermal therapy (PTT), which converts light energy to heat energy, has become a new research hotspot in cancer treatment. Although researchers have investigated various ways to improve the efficiency of tumor heat ablation to treat cancer, PTT may cause severe damage to normal tissue due to the systemic distribution of photothermal agents (PTAs) in the body and inaccurate laser exposure during treatment. To further improve the survival rate of cancer patients and reduce possible side effects on other parts of the body, it is still necessary to explore PTAs with high selectivity and precise treatment. In this review, we summarized strategies to improve the treatment selectivity of PTT, such as increasing the accumulation of PTAs at tumor sites and endowing PTAs with a self-regulating photothermal conversion function. The views and challenges of selective PTT were discussed, especially the prospects and challenges of their clinical applications.

A Borondifluoride-Complex-Based Photothermal Agent with an 80 % Photothermal Conversion Efficiency for Photothermal Therapy in the NIR-II Window

Small organic photothermal agents (SOPTAs) that absorb in the second near-infrared (NIR-II, 1000-1700 nm) window are highly desirable in photothermal therapy for their good biocompatibility and deeper tissue penetration. However, the design of NIR-II absorbing SOPTAs remains a great challenge. Herein, we report that molecular engineering of BF₂ complex via strengthening the donor-acceptor conjugation and increasing the intramolecular motions is an efficient strategy to achieve NIR-II absorbing SOPTAs with high photothermal performance. Based on this strategy, a BF₂ complex, BAF4, was designed and synthesized. BAF4 exhibits an intense absorption maximum at 1000 nm and negligible fluorescence. Notably, the nanoparticles of BAF4 achieve a high photothermal conversion efficiency value of 80 % under 1064 nm laser irradiation (0.75 W cm^-2 ). In vitro and in vivo studies reveal the great potential of BAF4 nanoparticles in photoacoustic imaging-guided photothermal therapy in the NIR-II window.

NIR-II Responsive Hollow Magnetite Nanoclusters for Targeted Magnetic Resonance Imaging-Guided Photothermal/Chemo-Therapy and Chemodynamic Therapy

Phototherapy in the second near-IR (1000-1700 nm, NIR-II) window has achieved much progress because of its high efficiency and relatively minor side effects. In this paper, a new NIR-II responsive hollow magnetite nanocluster (HMNC) for targeted and imaging-guided cancer therapy is reported. The HMNC not only provides a hollow cavity for drug loading but also serves as a contrast agent for tumor-targeted magnetic resonance imaging. The acid-induced dissolution of the HMNCs can trigger a pH-responsive drug release for chemotherapy and catalyze the hydroxyl radical (·OH) formation from the decomposition of hydrogen peroxide for chemodynamic therapy. Moreover, the HMNCs can adsorb and convert NIR-II light into local heat (photothermal conversion efficacy: 36.3%), which can accelerate drug release and enhance the synergistic effect of chemo-photothermal therapy. The HMNCs show great potential as a versatile nanoplatform for targeted imaging-guided trimodal cancer therapy.

Recent Progress on NIR-II Photothermal Therapy

Photothermal therapy is a very promising treatment method in the field of cancer therapy. The photothermal nanomaterials in near-infrared region (NIR-I, 750-900 nm) attracts extensive attention in recent years because of the good biological penetration of NIR light. However, the penetration depth is still not enough for solid tumors due to high tissue scattering. The light in the second near-infrared region (NIR-II, 1000-1700 nm) allows deeper tissue penetration, higher upper limit of radiation and greater tissue tolerance than that in the NIR-I, and it shows greater application potential in photothermal conversion. This review summarizes the photothermal properties of Au nanomaterials, two-dimensional materials, metal oxide sulfides and polymers in the NIR-II and their application prospects in photothermal therapy. It will arouse the interest of scientists in the field of cancer treatment as well as nanomedicine.

Carbon-Defect-Driven Boron Carbide for Dual-Modal NIR-II/Photoacoustic Imaging and Photothermal Therapy

Recently, tremendous attention has been evoked in the discovery of defect-engineered nanomaterials for near-infrared second window (NIR-II)-driven cancer therapy. Herein, we have constructed a novel type of carbon defects enriched in boron carbide nanomaterial (denoted as B₄C@C) through reacting B₄C and glucose by a hydrothermal method. The carbon defect concentration in B₄C@C has been significantly increased after coating with glucose; thus, B₄C@C exhibited a distinct photothermal response under the NIR-II window and the efficiency of photothermal conversion is determined to reach 45.4%, which is higher than the carbon-based nanomaterials in the NIR-II region. Both Raman spectra and X-ray photoelectron spectroscopy (XPS) spectra reveal that B₄C@C has rich sp²-hybridized carbon defects and effectively increases the NIR-II window light absorption capacity, thus enhancing the nonradiative recombination rate and improving the NIR-II photothermal effect. Furthermore, the B₄C@C nanosheets allows for tumor phototherapy and simultaneous photoacoustic imaging. This work indicates the huge potential of B₄C@C as a novel photothermal agent, which might arise much attention in exploring boron-based nanomaterials for the advantage of cancer therapy.

Antibody-Based Targeted Interventions for the Diagnosis and Treatment of Skin Cancers

BACKGROUND

Cutaneous malignancies most commonly arise from skin epidermal cells. These cancers may rapidly progress from benign to a metastatic phase. Surgical resection represents the gold standard therapeutic treatment of non-metastatic skin cancer while chemo- and/or radiotherapy are often used against metastatic tumors. However, these therapeutic treatments are limited by the development of resistance and toxic side effects, resulting from the passive accumulation of cytotoxic drugs within healthy cells.

OBJECTIVE

This review aims to elucidate how the use of monoclonal Antibodies (mAbs) targeting specific Tumor Associated Antigens (TAAs) is paving the way to improved treatment. These mAbs are used as therapeutic or diagnostic carriers that can specifically deliver cytotoxic molecules, fluorophores or radiolabels to cancer cells that overexpress specific target antigens.

RESULTS

mAbs raised against TAAs are widely in use for e.g. differential diagnosis, prognosis and therapy of skin cancers. Antibody-Drug Conjugates (ADCs) particularly show remarkable potential. The safest ADCs reported to date use non-toxic photo-activatable Photosensitizers (PSs), allowing targeted Photodynamic Therapy (PDT) resulting in targeted delivery of PS into cancer cells and selective killing after light activation without harming the normal cell population. The use of near-infrared-emitting PSs enables both diagnostic and therapeutic applications upon light activation at the specific wavelengths.

CONCLUSION

Antibody-based approaches are presenting an array of opportunities to complement and improve current methods employed for skin cancer diagnosis and treatment.

Recent near-infrared light-activated nanomedicine toward precision cancer therapy

Light has been present throughout the history of mankind and even the universe. It is of great significance to human life, contributing to energy, agriculture, communication, and much more. In the biomedical field, light has been developed as a switch to control medical processes with minimal invasion and high spatiotemporal selectivity. During the past three years, near-infrared (NIR) light as long-wavelength light has been applied to more than 3000 achievements in biological applications due to its deep penetration depth and low phototoxicity. Remotely controlled cancer therapy usually involves the conversion of biologically inert NIR light. Thus, various materials, especially nanomaterials that can generate reactive oxygen species (ROS), ultraviolet (UV)/visual light, or thermal energy and so on under NIR illumination achieve great potential for the research of nanomedicine. Here, we offered an overview of recent advances in NIR light-activated nanomedicine for cancer therapeutic applications. NIR-light-conversion nanotechnologies for both directly triggering nanodrugs and smart drug delivery toward tumor therapy were discussed emphatically. The challenges and future trends of the use of NIR light in biomedical applications were also provided as a conclusion. We expect that this review will spark inspiration for biologists, materials scientists, pharmacologists, and chemists to fight against diseases and boost the future clinical-translational applications of NIR technology-based precision nanomedicine.

Bi19S27I3 nanorods: a new candidate for photothermal therapy in the first and second biological near-infrared windows

Near-infrared (NIR) light-induced photothermal cancer therapy using nanomaterials as photothermal agents has attracted considerable research interest over the past few years. As the key factor in photothermal therapy systems, a variety of photothermal agents have been developed. However, the exploration of novel photothermal therapy nanoplatforms with high NIR absorption remains a significant challenge, especially those working in both NIR-I and NIR-II windows. In this work, Bi19S27I3 nanorods with remarkably high absorption covering the whole visible light to the entire NIR-I and NIR-II regions have been successfully prepared through a facile solvothermal approach. The as-synthesized Bi19S27I3 nanorods have a high photothermal conversion efficiency of 42.7% at 808 nm (NIR-I) and 41.5% at 1064 nm (NIR-II), making them a promising candidate for photothermal therapy. In vitro cell viability assay reveals that the Bi19S27I3 sample has good biocompatibility and exhibits significant cell-killing effect under NIR irradiation. In vivo anti-tumor experiments demonstrate that the tumor growth can be effectively inhibited by fatal hyperthermia ablation mediated by Bi19S27I3 nanorods under the irradiation of an 808 nm or 1064 nm laser. Therefore, this study should be primarily beneficial for the development of new materials for NIR photothermal therapy applications.

Self-assembled organic nanomedicine enables ultrastable photo-to-heat converting theranostics in the second near-infrared biowindow

Development of organic theranostic agents that are active in the second near-infrared (NIR-II, 1000-1700 nm) biowindow is of vital significance for treating deep-seated tumors. However, studies on organic NIR-II absorbing agents for photo-to-heat energy-converting theranostics are still rare simply because of tedious synthetic routes to construct extended π systems in the NIR-II region. Herein, we design a convenient strategy to engineer highly stable organic NIR-II absorbing theranostic nanoparticles (Nano-BFF) for effective phototheranostic applications via co-assembling first NIR (NIR-I, 650-1000 nm) absorbing boron difluoride formazanate (BFF) dye with a biocompatible polymer, endowing the Nano-BFF with remarkable theranostic performance in the NIR-II region. In vitro and in vivo investigations validate that Nano-BFF can serve as an efficient theranostic agent to achieve photoacoustic imaging guided deep-tissue photonic hyperthermia in the NIR-II biowindow, achieving dramatic inhibition toward orthotopic hepatocellular carcinoma. This work thus provides an insight into the exploration of versatile organic NIR-II absorbing nanoparticles toward future practical applications.

Photothermal treatment of oropharyngeal cancer with carbon-defective silicon carbide

Oral squamous carcinoma (OSCC) is a clinical common tumor with high recurrence rate and low 5 year survival rate. In this work, photothermal antitumor treatment has been performed to treat OSCC by taking anti-wound infection into consideration. By introducing C defects, we have successfully converted the semi-conductive SiC into metallic carbon-defective silicon carbide (SiC1-x), and endowed it with the near infrared absorption property for photothermal therapy (PTT). The results revealed that SiC1-x mediated PTT treatment could remove solid OSCC tumor in a biosafe way, showing low hematotoxicity, cytotoxicity and tissue toxicity. Moreover, the low invasion of PTT treatment could not only prevent the invasion of bacteria, but also realize an antibacterial effect on the wound, both of which are important for oral surgery. SiC1-x could be excreted from the body post treatment, which thus reduces the long-term potential toxicity. On the whole, this study provided a promising way to treat OSCC in an effective and safe way.

Microwave-triggered/HSP-targeted gold nano-system for triple-negative breast cancer photothermal therapy

Due to the lack of effective therapeutic targets and the passive delivery of a limited quantity of nanoparticles to the tumors, the photothermal conversion agents used in photothermal therapy (PTT) have not been effective in treating triple-negative breast cancer (TNBC). As a result, there is a need to improve the tumor-targeting ability of these photothermal conversion agents. To address this, a microwave-triggered heat shock protein (HSP)-targeted gold nano-system (cmHSP-AuNC), with a gold nanocage (AuNC) as a photothermal conversion agent and anti-HSP monoclonal antibody (cmHSP) as a targeting ligand, was fabricated. cmHSP-AuNC was characterized based on morphology, particle size, zeta potentials, absorption spectrum, and photothermal conversion ability. The expression of HSP70 in 4T1 cells after microwave irradiation was verified by western blotting, and the optimal treatment conditions to achieve the highest expression were determined. Both in vitro and in vivo results indicated that the induction through microwave irradiation could effectively activate the HSP70 overexpression in TNBC, thereby significantly improving the targeting ability, tumor accumulation and anti-tumor efficacy of cmHSP-AuNC. This study proposes a promising strategy for improving the targeting ability and therapeutic efficacy of PTT.

Near-infrared-II activated inorganic photothermal nanomedicines

The emergence of near-infrared-II (NIR-II) activated photomedicines has extended the penetration depth for noninvasive theranostics, especially for photothermal nanomedicines. The current early development stage for NIR-II activated photomedicines has focused on creating a greater variety of photothermal agents (PTAs) with superior photothermal conversion ability. However, there is no thorough review for NIR-II inorganic PTAs and most comparisons of the photothermal performances of NIR-II inorganic PTAs are made with NIR-I PTAs. This review will first discuss about the key mechanisms of NIR-II absorption and photothermal conversion. Subsequently, this review will summarize recently developed advanced NIR-II inorganic PTAs based on the dominant inorganic elements and provide a comparison of their NIR-II photothermal performances. The nanostructure design, enhancement strategies and potential biomedical applications will be listed and discussed. We hope this review will further inspire active development and study of NIR-II activated inorganic PTAs with good photothermal conversion ability, multifunctionality, biocompatibility or biodegradability, and disease targeting ability.

Antibody-Based Immunotherapy: Alternative Approaches for the Treatment of Metastatic Melanoma

Melanoma is the least common form of skin cancer and is associated with the highest mortality. Where melanoma is mostly unresponsive to conventional therapies (e.g., chemotherapy), BRAF inhibitor treatment has shown improved therapeutic outcomes. Photodynamic therapy (PDT) relies on a light-activated compound to produce death-inducing amounts of reactive oxygen species (ROS). Their capacity to selectively accumulate in tumor cells has been confirmed in melanoma treatment with some encouraging results. However, this treatment approach has not reached clinical fruition for melanoma due to major limitations associated with the development of resistance and subsequent side effects. These adverse effects might be bypassed by immunotherapy in the form of antibody–drug conjugates (ADCs) relying on the ability of monoclonal antibodies (mAbs) to target specific tumor-associated antigens (TAAs) and to be used as carriers to specifically deliver cytotoxic warheads into corresponding tumor cells. Of late, the continued refinement of ADC therapeutic efficacy has given rise to photoimmunotherapy (PIT) (a light-sensitive compound conjugated to mAbs), which by virtue of requiring light activation only exerts its toxic effect on light-irradiated cells. As such, this review aims to highlight the potential clinical benefits of various armed antibody-based immunotherapies, including PDT, as alternative approaches for the treatment of metastatic melanoma.

Inflammation-responsive functional Ru nanoparticles combining a tumor-associated macrophage repolarization strategy with phototherapy for colorectal cancer therapy

Due to the complexity and heterogeneity of solid tumors, traditional clinical treatments often only achieve limited therapeutic effects. Tumor-associated macrophages (TAMs) play a key role in the development of solid tumors, and the elimination of solid tumors based on the tumor microenvironment has proven to be an effective therapeutic strategy. Here, we successfully developed Ru-based nanoparticles, Ru@ICG-BLZ NPs, with inflammation-responsive release ability, which could repolarize TAMs into M1 macrophages (with an antitumor role) and further produce hyperthermia and ROS to eliminate cancer cells. In vitro experiments showed that Ru@ICG-BLZ NPs had superior drug (ICG and BLZ-945) loading capacity and sensitive inflammation-responsive drug release behavior, which enhanced CT26 cell uptake and penetration ability. Furthermore, in vivo experiments showed that Ru@ICG-BLZ NPs could effectively up-regulate the expression of M1 markers (iNOS, and IL-12) and exert phototherapy to ablate solid tumor, without causing obvious damage to the surrounding tissues of the tumor. The lower toxicity and excellent antitumor ability of Ru@ICG-BLZ NPs could provide new ideas for the clinical transformation of nanomedicine.

Rational Design of Conjugated Small Molecules for Superior Photothermal Theranostics in the NIR-II Biowindow

Extensive recent progress has been made on the design and applications of organic photothermal agents for biomedical applications because of their excellent biocompatibility comparing with inorganic materials. One major hurdle for the further development and applications of organic photothermal agents is the rarity of high-performance materials in the second near-infrared (NIR-II) window, which allows deep tissue penetration and causes minimized side effects. Up till now, there have been few reported NIR-II-active photothermal agents and their photothermal conversion efficiencies are relatively low. Herein, optical absorption of π-conjugated small molecules from the first NIR window to the NIR-II window is precisely regulated by molecular surgery of substituting an individual atom. With this technique, the first demonstration of a conjugated oligomer (IR-SS) with an absorption peak beyond 1000 nm is presented, and its nanoparticle achieves a record-high photothermal conversion efficiency of 77% under 1064 nm excitation. The nanoparticles show a good photoacoustic response, photothermal therapeutic efficacy, and biocompatibility in vitro and in vivo. This work develops a strategy to boost the light-harvesting efficiency in the NIR-II window for cancer theranostics, offering an important step forward in advancing the design and application of NIR-II photothermal agents.

Activatable NIR-II photoacoustic imaging and photochemical synergistic therapy of MRSA infections using miniature Au/Ag nanorods

Multidrug-resistant Staphylococcus aureus (MRSA) seriously endanger human health. The development of efficient methods to eliminate the infections and monitor the treatment process are of great significance. Near-infrared-II (NIR-II) photoacoustic (PA) imaging and photothermal therapy (PTT) are highly integrated theranostic platforms with superior performance including a low imaging background, increased tissue penetration depth, and high photothermal threshold. Herein, we report an activatable near-infrared II (NIR-II) phototheranostic strategy using miniature Au/Ag nanorods (NRs) for the photochemical synergistic therapy of MRSA infections and in situ monitoring of the treatment progress. Au/Ag NRs were efficiently activated by ferricyanide solution and allowed to continuously release free Ag+ to eliminate MRSA, triggering NIR-II photothermal and PA performance enhancement. The activated NIR-II photothermal effect in turn accelerated the release of free Ag+ from Au/Ag NRs for the synergistic elimination of gram-positive Staphylococcus aureus and promoted wound healing. No photothermal damages or free Ag+-induced side effects were observed in treated mice. After synergistic treatment, a 20-fold NIR-II PA signal increase with a maximum signal-to-noise measurement of 9.5 was observed between the implanted site and normal tissue, enabling sensitive monitoring of Ag+ release process. The prepared Au/Ag NRs were stable and biocompatible, showing great potential for activatable NIR-II phototheranostic application.

Conjugated polymer nano-systems for hyperthermia, imaging and drug delivery

Hyperthermia has shown tremendous therapeutic efficiency in the treatment of cancer due to its controllability, minimal invasiveness and limited side effects compared to the conventional treatment techniques like surgery, radiotherapy and chemotherapy. To improve the precision of hyperthermia specifically to a tumor location, near infra-red (NIR) light activatable inorganic metal nanoparticles have served as effective photothermal therapy materials, but toxicity and non-biodegradability have limited their clinical applications. Conjugated polymer nanoparticles have overcome these limitations and are emerging as superior photothermal materials owing to their excellent light harvesting nature, biocompatibility and tunable absorption properties. In this review we focus on the development of organic conjugated polymers (polyaniline, polypyrrole, polydopamine etc.) and their nanoparticles, which have broad NIR absorption. Such materials elicit photothermal effects upon NIR stimulation and may also serve as carriers for delivery of therapeutic and contrast agents for combined therapy. Subsequently, the emergence of donor-acceptor based semiconducting polymer nanoparticles with strong absorbance that is tunable across the NIR have been shown to eradicate tumors by either hyperthermia alone or combined with other therapies. The design of multifunctional polymer nanoparticles that absorb near- or mid- infrared light for heat generation, as well as their diagnostic abilities for precise biomedical applications are highlighted.

Functional Fibers, Composites and Textiles Utilizing Photothermal and Joule Heating

This review focuses on the mechanism of adjusting the thermal environment surrounding the human body via textiles. Recently highlighted technologies for thermal management are based on the photothermal conversion principle and Joule heating for wearable electronics. Recent innovations in this technology are described, with a focus on reports in the last three years and are categorized into three subjects: (1) thermal management technologies of a passive type using light irradiation of the outside environment (photothermal heating), (2) those of an active type employing external electrical circuits (Joule heating), and (3) biomimetic structures. Fibers and textiles from the design of fibers and textiles perspective are also discussed with suggestions for future directions to maximize thermal storage and to minimize heat loss.

A biodegradable nanodrug of molybdenum silicide for photothermal oncotherapy

MoSi₂ is a clearable photothermal nanodrug that can be metabolized and excreted from the body via feces and urine.

Magnetic-induced graphene quantum dots for imaging-guided photothermal therapy in the second near-infrared window

Graphene quantum dots (GQDs) are considered emerging nanomaterials for photothermal therapy (PTT) of cancer due to their good biocompatibility and rapid excretion. However, the optical absorbance of GQDs in shorter wavelengths (<1000 nm) limits their overall therapeutic efficacies as photothermal agent in the second near infrared window (1000-1700 nm, NIR-II). Herein, we report a type of GQDs with strong absorption (1070 nm) in NIR-II region that was synthesized via a one-step solvothermal treatment using phenol as single precursor by tuning the decomposition of hydrogen peroxide under a high magnetic field with an intensity of 9T. The obtained 9T-GQDs demonstrate uniform size distribution (3.6 nm), and tunable fluorescence (quantum yield, 16.67%) and high photothermal conversion efficacy (33.45%). In vitro and in vivo results indicate that 9T-GQDs could efficiently ablate tumor cells and inhibit the tumor growth under NIR-II irradiation. Moreover, the 9T-GQDs exhibited enhanced NIR imaging of tumor in living mice, suggesting the great probability of using 9T-GQDs for in vivo NIR imaging-guided PTT in the NIR-II window.

Antiangiogenesis-Combined Photothermal Therapy in the Second Near-Infrared Window at Laser Powers Below the Skin Tolerance Threshold

Photothermal agents with strong light absorption in the second near-infrared (NIR-II) region (1000-1350 nm) are strongly desired for successful photothermal therapy (PTT). In this work, titania-coated Au nanobipyramids (NBP@TiO₂) with a strong plasmon resonance in the NIR-II window were synthesized. The NBP@TiO₂ nanostructures have a high photothermal conversion efficiency of (93.3 ± 5.2)% under 1064-nm laser irradiation. They are also capable for loading an anticancer drug combretastatin A-4 phosphate (CA4P). In vitro PTT studies reveal that 1064-nm laser irradiation can efficiently ablate human lung cancer A549 cells and enhance the anticancer effect of CA4P. Moreover, the CA4P-loaded NBP@TiO₂ nanostructures combined with PTT induce a synergistic antiangiogenesis effect. In vivo studies show that such CA4P-loaded NBP@TiO₂ nanostructures under mild 1064-nm laser irradiation at an optical power density of 0.4 W cm^-2, which is lower than the skin tolerance threshold value, exhibit a superior antitumor effect. This work presents not only the development of the NBP@TiO₂ nanostructures as a novel photothermal agent responsive in the NIR-II window but also a unique combined chemo-photothermal therapy strategy for cancer therapy.

Photothermal Polymer Nanocomposites of Tungsten Bronze Nanorods with Enhanced Tensile Elongation at Low Filler Contents

We present polymer nanocomposites of tungsten bronze nanorods (TBNRs) and ethylene propylene diene monomers (EPDM). The combination of these components allows the simultaneous enhancement in the mechanical and photothermal properties of the composites at low filler contents. The as-synthesized TBNRs had lengths and diameters of 14.0 ± 2.4 nm and 2.5 ± 0.5 nm, respectively, and were capped with oleylamine, which has a chemical structure similar to EPDM, making the TBNRs compatible with the bulk EPDM matrix. The TBNRs absorb a wide range of near-infrared light because of the sub-band transitions induced by alkali metal doping. Thus, the nanocomposites of TBNRs in EPDM showed enhanced photothermal properties owing to the light absorption and subsequent heat emission by the TBNRs. Noticeably, the nanocomposite with only 3 wt% TBNRs presented significantly enhanced tensile strain at break, in comparison with those of pristine EPDM, nanocomposites with 1 and 2 wt % TBNRs, and those with tungsten bronze nanoparticles, because of the alignment of the nanorods during tensile elongation. The photothermal and mechanical properties of these nanocomposites make them promising materials for various applications such as in fibers, foams, clothes with cold weather resistance, patches or mask-like films for efficient transdermal delivery upon heat generation, and photoresponsive surfaces for droplet transport by the thermocapillary effect in microfluidic devices and microengines.

W-doped TiO2 nanoparticles with strong absorption in the NIR-II window for photoacoustic/CT dual-modal imaging and synergistic thermoradiotherapy of tumors

Multifunctional nanomaterials that have integrated diagnostic and therapeutic functions and low toxicity, and can enhance treatment efficacy through combination therapy have drawn tremendous amounts of attention. Herein, a newly developed multifunctional theranostic agent is reported, which is PEGylated W-doped TiO2 (WTO) nanoparticles (NPs) synthesized via a facile organic route, and the results demonstrated strong absorbance of these WTO NPs in the second near-infrared (NIR-II) window due to successful doping with W. These PEGylated WTO NPs can absorb both NIR-II laser and ionizing radiation, rendering them well suited for dual-modal computed tomography/NIR-II photoacoustic imaging and synergistic NIR-II photothermal/radiotherapy of tumors. In addition, the long-term in vivo studies indicated that these PEGylated WTO NPs had no obvious toxicity on mice in vivo, and they can be cleared after a 30-day period. In summary, this multifunctional theranostic agent can absorb both NIR-II laser and ionizing radiation with negligible toxicity and rapid clearance, therefore it has great promise for applications in imaging and therapeutics in biomedicine.

Tailor-Made Semiconducting Polymers for Second Near-Infrared Photothermal Therapy of Orthotopic Liver Cancer

Liver tumor is one of the most lethal cancers due to its low ratio of surgical resection, high recurrence rate, and invasiveness. Photothermal therapy (PTT) possesses many advantages for cancer therapy because of its noninvasive nature. However, most PTT is conducted in the first near-infrared (NIR-I) window, so second near-infrared (NIR-II) photosensitizers with higher penetrating ability and clinical prospects are seriously desirable. Herein, a semiconducting polymer with optimized absorption in NIR-I and NIR-II regions is obtained by ternary copolymerization methodology. The prepared nanoparticle (NP) from the semiconducting polymer is used for treatment of orthotopic liver cancer upon laser irradiation. Compared with an 808 nm laser, a 1064 nm laser leads to more effective inhibition toward orthotopic liver cancer in the same conditions. These results thus demonstrate that the NIR-II polymeric NPs may inspire another aspect for highly efficient therapy of various orthotopic cancers.

PEGylated (NH4)xWO3 nanorod mediated rapid photonecrosis of breast cancer cells

Photothermal therapy has emerged as a potential minimally invasive technique to destroy malignant cells with high selectivity. It utilizes low band gap nanoscale materials as photothermal agents dispersed at the affected area to increase the temperature locally by absorbing radiation in the near infrared (NIR) region and destroys the cells. In an effort to develop a photothermal agent with high efficacy for photothermal therapy, we found that (NH4)xWO3 nanorods of length 0.5-1.0 μm and diameter ∼100 nm could destroy breast cancer cells rapidly when irradiated with a wavelength in the therapeutic window. The material was prepared using a solvothermal route followed by PEGylation for improving the biocompatibility. X-ray diffraction and transmission electron microscopy studies revealed the hexagonal crystal lattice of the material. The uniform wrapping of polyethylene glycol (PEG) around the nanorods was confirmed using energy dispersive spectroscopy elemental mapping. An 808 nm laser was used to investigate the photothermal responses of the material on SUM-159 and MCF-7 breast cancer cells in vitro. The PEGylated-(NH4)xWO3 nanorods exhibited rapid temperature elevation from 20 °C to 60 °C within 3 min upon irradiation. A significant growth inhibition of SUM-159 and MCF-7 breast cancer cells with photonecrosis was observed. PEGylated (NH4)xWO3 nanorods could potentially be used in cancer therapy due to their strong photonecrotic properties at specific NIR wavelengths that suffer from minimal attenuation while passing through biological tissues.

Metabolizable Semiconducting Polymer Nanoparticles for Second Near-Infrared Photoacoustic Imaging

Photoacoustic (PA) imaging in the second near-infrared (NIR-II) window (1000-1700 nm) holds great promise for deep-tissue diagnosis due to the reduced light scattering and minimized tissue absorption; however, exploration of such a noninvasive imaging technique is greatly constrained by the lack of biodegradable NIR-II absorbing agents. Herein, the first series of metabolizable NIR-II PA agents are reported based on semiconducting polymer nanoparticles (SPNs). Such completely organic nanoagents consist of π-conjugated yet oxidizable optical polymer as PA generator and hydrolyzable amphiphilic polymer as particle matrix to provide water solubility. The obtained SPNs are readily degraded by myeloperoxidase and lipase abundant in phagocytes, transforming from nonfluorescent nanoparticles (30 nm) into NIR fluorescent ultrasmall metabolites (≈1 nm). As such, these nanoagents can be effectively cleared out via both hepatobiliary and renal excretions after systematic administration, leaving no toxicity to living mice. Particularly these nanoagents possess high photothermal conversion efficiencies and emit bright PA signals at 1064 nm, enabling sensitive NIR-II PA imaging of both subcutaneous tumor and deep brain vasculature through intact skull in living animals at a low systematic dosage. This study thus provides a generalized molecular design toward organic metabolizable semiconducting materials for biophotonic applications in NIR-II window.

SnxWO3 as a theranostic platform for realizing multi-imaging-guided photothermal/photodynamic combination therapy

Precise oncotherapy requires effective cancer treatments that are guided by clinical imaging techniques. One of the most representative cases is multi-imaging-guided phototherapy. This study presents a novel multifunctional theranostic agent of SnxWO3 tungsten bronze, which is an excellent light absorber in the near infrared (NIR) range. Theoretical calculations based on density functional theory confirm that the insertion of donor Sn atoms into orthorhombic WO3 gives rise to the broadband visible-NIR absorption. Accordingly, both the photothermal effect and reactive oxygen species (ROS) production could be realized under NIR light irradiation by SnxWO3 tungsten bronze nanocrystals, thereby triggering the potent in vivo photothermal and photodynamic synergistic therapy. Meanwhile, modified SnxWO3 tungsten bronze has the functions of photoacoustic imaging (PAI), X-ray computed tomography (CT) imaging and near-infrared fluorescence (NIRF) imaging for tumor detection as well. Finally, for investigating the antitumor mechanism of in vivo solid tumors, clinical imaging modalities of B-mode ultrasonography (US) and magnetic resonance imaging (MRI) are employed to monitor the tumor evolution process after the photo-treatment, verifying a typically liquefactive necrosis process. These results indicate that the SnxWO3 tungsten bronze nanostructure is a promising theranostic agent for imaging-guided cancer therapy.

Ultra-small bimetallic iron–palladium (FePd) nanoparticle loaded macrophages for targeted tumor photothermal therapy in NIR-II biowindows and magnetic resonance imaging

Nanoparticles working in the NIR-II biowindows possess larger maximum permissible exposure (MPE) and desirable penetration depth to the laser. However, most NIR-II responsive nanomaterials lack tumor targeting and Magnetic Resonance Imaging (MRI) ability. This greatly limits their applications. This study reported ultra-small bimetallic iron–palladium (FePd) nanoparticle loaded macrophages for targeted tumor photothermal therapy in NIR-II biowindows and magnetic resonance imaging. The crystal phase, morphology, absorption spectrum and photothermal performance of the synthesized samples were systematically characterized. The effects of photothermal therapy and nuclear magnetic imaging (MRI) were studied both in vitro and in vivo. Since FePd nanoparticles have both iron and palladium elements, it had a good MRI imaging capability and high photothermal conversion efficiency (36.7%). After binding to macrophages, FePd nanoparticles@macrophages (FePd@M) showed a good tumor targeting ability and were used for targeting NIR-II photothermal therapy and MRI imaging of tumors. The results of photothermal treatment showed that the tumor volume decreased by 90% compared to the control group, and no significant organ toxicity was observed. The results of MRI imaging showed that the FePd@M has the best imaging effect. The nanoparticles with the excellent NIR-II PTT ability and MRI effect have overcome the problem of tumor targeting and avoid the rapid removal of ultra-small nanoparticles. The FePd@M delivery system provides new ideas for material construction in the NIR-II region and has great clinical application potential.

Nanoparticles working in the NIR-II biowindows possess larger maximum permissible exposure (MPE) and desirable penetration depth to the laser.

Facile synthesis of urchin-like CsxWO3 particles with improved transparent thermal insulation using bacterial cellulose as a template

Urchin-like Cs_xWO₃ particles were synthesized using bacterial cellulose (BC) as a template by the hydrothermal method. The effects of the BC addition amount on the morphology, W⁵⁺ content and transparent thermal insulation of Cs_xWO₃ were studied. It has been confirmed that abnormal growth of Cs_xWO₃ rods was greatly reduced after introduction of BC into the precursor solution. Moreover, introduction of BC into the precursor solution could significantly improve the transparent thermal insulation properties of the Cs_xWO₃ film. In particular, when the BC amount was appropriate, the prepared Cs_xWO₃ film exhibited better visible transparency, with the visible light transmittance (T_Vis) more than 60%. In addition, the urchin-like particles could be transformed into small size nanorods after H₂ heat-treatment, exhibiting excellent visible light transparency and thermal insulation performance. In particular, it has been proved that the 20BC-HT-Cs_xWO₃ film exhibits excellent thermal insulation performance, and shows broad application prospects in the field of solar heat filters and energy-saving window glass.

Urchin-like Cs_xWO₃ particles were synthesized using bacterial cellulose (BC) as a template by the hydrothermal method. The BC could greatly reduce the abnormal growth of Cs_xWO₃ rods and improve the transparent heat-insulation properties of Cs_xWO₃ film.