Microscale Heat Transfer Transduced by Surface Plasmon Resonant Gold Nanoparticles

Adipose-targeted nanohybrid as a browning inducer for synergistic hyperthermia-pharmacotherapy of obesity

Inducing adipose browning to increase energy expenditure has recently emerged as a promising approach for antiobesity treatment. However, its therapeutic efficacy is often limited by poor adipose-targeted drug delivery and suboptimal browning efficiency. To address these challenges, an adipose-targeting aptamer (Apt8) and browning agent resveratrol (Res) were used to construct an Apt-modified and Res-loaded degradable mesoporous silica-coated Au nanorods nanocarriers (NC), termed Res@NC@Apt8, achieving adipose-targeted hyperthermia-pharmacotherapy. Upon internalization by adipocytes, laser irradiation induces mild local hyperthermia (LHT) via Res@NC@Apt8, triggering calcium ion (Ca2+) influx. Simultaneously, the interaction of the nanohybrid with local glutathione (GSH) releases Res. The dual mechanisms activate the adenosine 5'-monophosphate-activated protein kinase (AMPK) pathway, reduce the lipid droplet content, enhance mitochondrial biogenesis, and accelerate metabolism, thereby synergistically promoting adipose browning. Intravenous Res@NC@Apt8 administration in obese mice significantly drives adipose reduction and further achieves excellent antiobesity therapeutic efficacy. This synergistic treatment achieves a superior weight reduction of 17.2% compared with 6.9% and 10.6% achieved using LHT and pharmacotherapy alone, respectively. This study introduces a novel strategy for achieving activatable LHT and drug release for synergetic obesity treatment.

NO-producing Arg-sCNDs for combined photothermal and gas effects in cancer cell ablation

Photothermal therapy (PTT) and gas therapy (GT) were used in combination to enhance the antitumor effect by leveraging the dual cytotoxic mechanisms of nitric oxide (NO) and peroxynitrite (ONOO-), along with the localized heating capability of photothermal materials. Arginine-supra-carbon nanodots (Arg-sCNDs) were obtained through a one-pot hydrothermal method without subsequent modification, allowing them to produce endogenous NO and photothermal effects on a single platform. The photothermal conversion efficiency of Arg-sCNDs reaches 77.09% and 58.01% under 730 nm and 808 nm irradiation, respectively. Arg-sCNDs demonstrated good killing and ablation effects on cancer cells and had minimal side effects on normal cells. The photothermal and NO effects reinforce each other. The cell apoptosis mechanism was demonstrated through measurements of cell temperature, NO levels, ONOO- levels, and mitochondrial membrane potential. Therefore, the in vitro study demonstrated that Arg-sCNDs with dual functions present broad application prospects in tumor cell ablation.

An All-in-One Nanoheater and Optical Thermometer Fabricated from Fractal Nanoparticle Assemblies

We designed and optimized a dual-functional photothermal agent that performs as a nanoheater and real-time optical thermometer by leveraging gold nanoparticle (AuNP) self-assembly and anti-Stokes thermometry. We engineered colloidally stable fractal AuNP clusters with well-defined nanogaps to absorb strongly in the near-infrared and enhance anti-Stokes vibrational modes via surface-enhanced Raman scattering (SERS) for electromagnetic (EM) hotspot-localized thermometry during plasmonic heating. Photothermal characterization and simulations of a range of AuNP building block sizes demonstrated that 40 nm AuNPs are optimum for combined plasmonic heating and SERS due to the high probability of in resonance chains within assemblies. We explored the relationship between the far-field of our AuNP clusters and the near-field enhancement of anti-Stokes modes in the context of SERS thermometry, setting out design considerations for applying SERS thermometry. Finally, using a single near-infrared (NIR) laser source, we demonstrated plasmonic heating of a colloidal system with simultaneous accurate temperature measurement from EM hotspots via the thermal information encoded in the anti-Stokes mode of surface-bound Raman reporter molecules. Ultimately, our approach could enable real-time noninvasive temperature feedback from plasmonic nanoparticles within tumor tissue environments to guide safe and effective temperature increases during cancer photothermal therapy.

In Vitro and In Vivo Photothermal and Photoacoustic Activities of Polymeric Nanoparticles Loaded with Nickel, Palladium, and Platinum-Bis(dithiolene) Complexes

The development of nanosystems with enhanced photothermal and photoacoustic properties is crucial for advancing theranostic applications in cancer therapy. This study explores polymeric nanoparticles (NPs) constituted by a biocompatible poly(ethylene glycol)-block-poly(benzyl malate) copolymer and loaded with metal-bis(dithiolene) complexes (M = Ni, Pd, Pt). These NPs, prepared via a robust nanoprecipitation method, demonstrate uniform morphology, efficient encapsulation (≈70%), and tailored near-infrared (NIR) optical absorption properties. Photothermal and photoacoustic evaluations reveal superior performance of palladium-loaded NPs, offering high contrast for imaging and significant temperature increases under NIR laser irradiation. Cytotoxicity assays confirm their nontoxicity without laser exposure, while effective cancer cell eradication is achieved upon irradiation at power densities ≥2 W cm-2. In vivo experiments on zebrafish embryos bearing human cancer xenografts show significant tumor size reduction (20%) post-treatment with palladium-loaded NPs under 880 nm laser irradiation. These findings underscore that metal-bis(dithiolene)-loaded NPs can be versatile agents for combined diagnostics and photothermal therapy, paving the way for further optimization and clinical translation.

Engineered gold nanoparticles for accurate and full-scale tumor treatment via pH-dependent sequential charge-reversal and copper triggered photothermal-chemodynamic-immunotherapy

Current anti-tumor strategies majorly rely on the targeted delivery of functional nanomedicines to tumor region, neglecting the importance of effective infiltration of these nanomedicines in whole tumor tissue. This process normally causes the quick endocytosis by the tumor cells at surface layer of tumor tissue, resulting in the restriction of the penetration of these nanomedicines and limited therapeutic region, which would not be able to treat the entire tumor tissue. Herein, we prepared a series of engineered gold nanoparticles (Au-MBP NPs) with step-wise charge reversal in different acid environments that could entirely infiltrate into the whole tumor tissue and then perform tumor-specific photothermal-chemodynamic-immunotherapy to achieve the complete and accurate tumor treatment. These Au-MBP NPs consisted of AuNPs, thiol modified piperidine (SH-PD, charge reversal group), thiol modified benzoyl thiourea (SH-BTU, copper chelator) and 11-mercaptoundecanoic acid (MUA) with different proportions. Once these Au-MBP NPs arrived tumor tissue, the decreasing pH values from shallow to deep region of tumor tissue separately induced the charge reversal of these nanoparticles from negative to positive, allowing them to bind with negatively charged tumor cells at designed area to occupy the whole tumor for further therapy. Following with the internalization by tumor cells, these Au-MBP NPs would selectively capture the excessive Cu2+ to decrease the available copper in tumor cells, resulting in the inhibition of tumor metastasis via the copper metabolism blockade. On one hand, the captured Cu2+ also induced the aggregation of Au-MBP NPs, which in situ generated the photothermal agents in tumor cells for tumor-specific photothermal therapy (PTT). On the other hand, the chelated Cu2+ ions were reduced to Cu+, which catalyzed the high concentration of intracellular H2O2 to produce cytotoxic hydroxyl radical (•OH), exerting tumor-specific chemodynamic therapy (CDT). Furthermore, the immune-associated tumor antigens were also generated during PTT and CDT processes via immunogenic cell death (ICD), which further matured the dendritic cells (DCs) and then activated CD4+ and CD8+ T cells to turn on the immunotherapy, resulting in additional anti-tumor and anti-metastasis effects. Both in vitro and in vivo results indicated that these Au-MBP NPs possessed enormous potential for effectively suppressing primary and metastatic tumors.

BODIPY-Based Photothermal Agent Incorporating Azulene for Enhanced NIR Absorption and Tumor Ablation

Photothermal therapy (PTT) is a promising minimally invasive treatment that converts light energy into localized heat for tumor ablation. Indocyanine green (ICG), the only clinically approved photothermal agent (PTA), suffers from rapid photobleaching and poor tumor retention, underscoring the urgent need for next-generation PTAs with improved properties. In this study, we report AzuGlu-BODIPY, a novel azulene-containing BODIPY-based PTA incorporating 1,2,3,4-tetrahydroquinoline and glucose, designed to overcome these limitations. AzuGlu-BODIPY demonstrates a high photothermal conversion efficiency (PCE) of 51%, effective near-infrared (NIR) absorption, and thermal stability in both dimethyl sulfoxide (DMSO) and aqueous solutions. In vitro studies revealed potent photothermal efficacy against cancer cell lines, with IC50 values of 3.1-4.6 μM under 808 nm laser irradiation, while in vivo experiments showed complete tumor regression in 4T1 tumor-bearing mice following localized administration and laser treatment. These results suggest AzuGlu-BODIPY as a promising PTA and provide a versatile platform for advancing azulene-based PTAs with enhanced functionality for PTT.

Responsive plasmonic hybrid nanorods enables metabolism reprogramming via cuproptosis-photothermal combined cancer therapy

Abnormal tumor metabolism leads to tumor growth, metastasis, and recurrence, reprogramming tumor metabolism and activating potent anti-tumor immune response have been demonstrated to have good therapeutic effects on tumor elimination. Copper-based nanomaterials involved in cuproptosis show great prospects in these two aspects, but their efficiency is restricted by Cu homeostasis and the toxicity of the chelator. Here, the pH-responsive AuNRs@Cu2O core-shell plasmonic hybrid nanorods (ACNRs) have been successfully fabricated to realize microenvironment-controlled release at the tumor site for the combined therapy of cuproptosis and photothermal treatment. The AuNRs core exhibited excellent NIR-II photothermal property, which boost the intracellular concentration of copper to trigger severe cuproptosis and induce immunogenic cell death of tumor cells. In vivo studies demonstrated the ACNR exhibited efficient tumor therapy for primary, metastatic, and recurrent tumors. ACNRs-induced cuproptosis and PTT were capable of reprogramming energy metabolism, leading to a decreased production of lactic acid. This potential of metabolic reprogramming assisted in reshaping the immunosuppressive tumor microenvironment to facilitate the infiltration of immune cells and boost the immune responses triggered by PTT. The therapeutic mechanism was further verified by metabolomics analysis, which indicated that ACNRs + PTT treatment led to the inhibition of the Pentose Phosphate Pathway and Glycolysis pathways in tumor cells. The suppression of glycolytic reduced ATP synthesis, thereby hindering energy-dependent copper efflux, which in turn promoted cuproptosis. Taken together, this study offers promising insights for cuproptosis-based cancer treatment and sheds new light on nanomedicine-mediated metabolic modulation for future tumor therapy.

Mitochondria-targeted photothermal-chemodynamic therapy enhances checkpoint blockade immunotherapy on colon cancer

Immunotherapy has emerged as a hotspot for cancer treatment. However, the response rate of monotherapy remains relatively low in clinical settings. Photothermal therapy (PTT), which employs light energy to ablate tumors, can also activate tumor-specific immune responses. This effect has been attributed in several studies to the release of damage-associated molecular patterns (DAMPs) triggered by mitochondrial injury. We propose that mitochondria-targeted PTT may better synergize with immunotherapy. Herein, we constructed a multifunctional nanoplatform that enables mitochondria-targeted photothermal-chemodynamic combination therapy by conjugating indocyanine green-thiol (ICG-SH) and mercaptoethyl-triphenylphosphonium (TPP-SH) onto polyvinyl pyrrolidone (PVP)-coated gold-copper nanoparticles (AIT). Upon near-infrared light (NIR) irradiation, AIT ablates cancer cells and amplifies the effect of chemodynamic therapy (CDT), thereby inducing apoptosis in the tumor. The combination of CDT and PTT promotes immunogenic cell death, which could synergize with checkpoint blockade immunotherapy. In a bilateral mouse colon cancer model, we observed complete eradication of light-irradiated primary tumors and significant inhibition of distant untreated tumors in the group treated with AIT plus anti-PD-1 (αPD-1). We found a significant increase in serum levels of pro-inflammatory factors, including interleukin-6 (IL-6), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α), following PTT/CDT/immunotherapy treatment, suggesting effective activation of the immune response. The enhanced immunogenicity caused by AIT with αPD-1 treatment resulted in efficient antigen presentation, as indicated by the increased infiltration of dendritic cells (DCs) into the tumor-draining lymph nodes (LNs). We also observed enhanced infiltration of CD8+ T cells in distant tumors in the AIT with αPD-1 group compared to αPD-1 alone. Hence, mitochondria-targeting represents an effective strategy to potentiate the combination of photothermal, chemodynamic, and immune checkpoint blockade therapies for the treatment of metastatic cancer.

Active Iron-Drug Nanocomplexes Improve Photodynamic and Photothermal Cancer Therapy by Mitigating Tumor Hypoxia and Counteracting Tumor Heat Resistance

Photodynamic therapy (PDT) and photothermal therapy (PTT) offer the advantages of precise temporal and spatial selectivity in cancer treatment, minimizing damage to normal cells while effectively eliminating tumor cells. However, the therapeutic efficacy of phototherapy is always hindered by challenges such as hypoxia and tumor heat resistance. Herein, a pH-responsive metal-drug nanocomplex (denoted as PAFH) comprising hypericin (HYP), apigenin (APG), polyvinylpyrrolidone (PVP), and Fe3+ is developed to enhance the therapeutic efficacy of PDT and PTT. The PAFH nanocomplex exhibits photothermal properties under 808 nm laser irradiation, which can disassociate in response to the acidic tumor microenvironment and the temperature increase induced by PTT, thereby eventually triggering the on-site release of APG and HYP. The released APG inhibits the synthesis of heat shock protein HSP-90, facilitating the PAFH-mediated PTT to kill tumor cells at mild temperature. Additionally, APG alleviates hypoxia and then regulates the expression of hypoxia-inducible factor HIF-1𝛼, increasing cellular oxygen levels to produce singlet oxygen for enhanced HYP-mediated PDT and inhibiting tumor metastasis. Ultimately, this sophisticated nanosystem represents an advanced strategy to promote PDT and PTT by mitigating tumor hypoxia and counteracting tumor heat resistance, significantly improving therapeutic efficacy for precise cancer therapy.

Ti3C2/CuWO4/Pt nanozyme: photothermal-enhanced chemodynamic antibacterial effects induced by NIR

With the growing issue of antibiotic resistance, it has become increasingly crucial to develop highly efficient antimicrobial materials. While the single-component nanozyme systems exhibited some catalytic activity, their efficiency remains suboptimal. This study presents a Ti3C2/CuWO4/Pt hybrid nanozyme composed of photothermal agents and nanozymes, which leverages the photothermal effect to enhance nanozyme activity and achieve efficient antimicrobial effects. The composite material exhibited peroxidase (POD)-like catalytic activity, effectively converting hydrogen peroxide (H2O2) into hydroxyl radicals (·OH). Meanwhile, the Ti3C2/CuWO4/Pt material demonstrated high photothermal conversion ability, which not only promoted the generation of ·OH under near-infrared (NIR) light irradiation, but also facilitated copper (Cu2+) ions release from the CuWO4 nanozyme, thereby further augmenting its catalytic activity. After 4 to 5 min of light irradiation, the Ti3C2/CuWO4/Pt nanozyme exhibited significant antimicrobial performance against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In summary, this work presents a Ti3C2/CuWO4/Pt nanoplatform that utilizes the photothermal effect to enhance the chemodynamic antimicrobial activity, showcasing its potential applications in antibiotic-free antimicrobial fields.

A PEGylated conjugated-BODIPY oligomer for NIR-II imaging-guided photothermal therapy

The integration of second near-infrared (NIR-II) fluorescence imaging and photothermal therapy (PTT) achieved precise and efficient tumor treatment. BODIPY, a promising fluorescent dye, is widely used in biological fluorescence imaging due to its excellent optical properties and chemical stability. However, the excitation wavelengths of BODIPY typically range from 530 nm to 650 nm within the visible spectrum, which significantly limits tissue penetration. In this work, a self-assembled nanoparticle (BODIPY4-PEG NP) was fabricated with a BODIPY-conjugated oligomer (BODIPY4) bearing a hydrophilic polyethylene glycol (PEG) chain. BODIPY4-PEG NPs exhibit excellent NIR-II emission, with a maximum fluorescence emission peak of 1123 nm. The outstanding imaging performance of BODIPY4-PEG NPs has been evaluated in the imaging of lymph nodes and the vascular system in mice, demonstrating excellent spatial resolution. Based on the excellent imaging performance and photothermal conversion efficiency (35%) of the BODIPY4-PEG NPs, they can be further utilized in NIR-II imaging-guided photothermal therapy. In a 4T1 tumor-bearing mouse model, BODIPY4-PEG NPs exhibited strong fluorescence under 980 nm laser irradiation and successfully induced heat generation to eliminate the tumor. To summarize, BODIPY4-PEG NPs contribute to the ongoing progress in the field of NIR-II fluorescence imaging-guided PTT.

Cu2-xO@Ti3C2 Integrated Photothermal Nanofibers with Antibacterial, Anti-Inflammatory, and Hemostatic Properties for Promoting Infected Diabetic Wound Healing

Infected diabetic wounds represent a significant challenge in clinical care due to persistent inflammation and impaired healing. To address these issues, the development of novel wound dressings with both antibacterial and reactive oxygen species (ROS) scavenging properties is essential. Herein, we prepare a novel wound dressing composed of Cu2-xO nanoparticles decorated on Ti3C2 MXene (Cu2-xO@Ti3C2) and integrate it into a poly(vinyl alcohol) (PVA) matrix to form electrospun nanofibers (Cu2-xO@Ti3C2@PVA). Cu2-xO@Ti3C2 exhibits remarkable photothermal conversion efficiency and effective ROS scavenging properties. In vitro experiments demonstrated that Cu2-xO@Ti3C2 effectively kills bacteria upon near-infrared (NIR) irradiation, which can be attributed to the photothermal therapy (PTT) effect of Ti3C2. At the same time, the ROS scavenging abilities of both Ti3C2 and Cu2-xO endow Cu2-xO@Ti3C2 with significant in vitro anti-inflammatory effects. As a promising wound dressing, in vivo studies validated the high efficacy of Cu2-xO@Ti3C2@PVA in promoting hemostasis, exerting antibacterial activity, reducing inflammation, and accelerating the healing process of diabetic wounds. This innovative approach provides a comprehensive solution to the multifaceted challenges of diabetic wound healing and paves the way for improved clinical outcomes.

Near Infrared Biomimetic Hybrid Magnetic Nanocarrier for MRI-Guided Thermal Therapy

Cell-membrane hybrid nanoparticles (NPs) are designed to improve drug delivery, thermal therapy, and immunotherapy for several diseases. Here, we report the development of distinct biomimetic magnetic nanocarriers containing magnetic nanoparticles encapsulated in vesicles and IR780 near-infrared dyes incorporated in the membranes. Distinct cell membranes are investigated, red blood cell (RBC), melanoma (B16F10), and glioblastoma (GL261). Hybrid nanocarriers containing synthetic lipids and a cell membrane are designed. The biomedical applications of several systems are compared. The inorganic nanoparticle consisted of Mn-ferrite nanoparticles with a core diameter of 15 ± 4 nm. TEM images show many multicore nanostructures (∼40 nm), which correlate with the hydrodynamic size. Ultrahigh transverse relaxivity values are reported for the magnetic NPs, 746 mM-1s-1, decreasing respectively to 445 mM-1s-1 and 278 mM-1s-1 for the B16F10 and GL261 hybrid vesicles. The ratio of relaxivities r2/r1 decreased with the higher encapsulation of NPs and increased for the biomimetic liposomes. Therapeutic temperatures are achieved by both, magnetic nanoparticle hyperthermia and photothermal therapy. Photothermal conversion efficiency ∼25-30% are reported. Cell culture revealed lower wrapping times for the biomimetic vesicles. In vivo experiments with distinct routes of nanoparticle administration were investigated. Intratumoral injection proved the nanoparticle-mediated PTT efficiency. MRI and near-infrared images showed that the nanoparticles accumulate in the tumor after intravenous or intraperitoneal administration. Both routes benefit from MRI-guided PTT and demonstrate the multimodal theranostic applications for cancer therapy.

Biomimetic Atorvastatin Self-Assembled Nanomedicine Inhibits the Cyclooxygenase-2/Prostaglandin E2 Pathway Enhanced Photothermal and Antitumor Immunity

Cancer continues to pose remarkable medical challenges worldwide. While current cancer therapies can lead to initial clinical improvement, they are often followed by recurrence, metastasis, and drug resistance, underscoring the urgent need for innovative treatment strategies. Atorvastatin calcium (AC), a widely used lipid-lowering and anti-inflammation drug in the clinic, has shown antitumor potential. To further improve the antitumor efficacy, we developed self-assembled AC and polydopamine (PDA) nanoparticles whose surface was coated with macrophage membranes (CM) as a biomimetic drug delivery system [AC@PDA@CM (APM)]. APM showed high drug-loading capacity, excellent stability, excellent bioavailability, and tumor-targeting ability, ultimately achieving photothermal synergistic cancer immunotherapy. Our findings indicate that APM efficiently delivers AC to tumor sites while leveraging photothermal therapy (PTT) to enhance local tumor ablation and antitumor immune effect. Notably, APM mitigates tumor immunosuppression triggered by PTT through AC, suppressing the COX-2/PGE2 pathway and immune evasion signal CD47. Furthermore, APM notably reduced nonspecific distribution and side effects, which is conducive to ensuring the safety level of medication. This integrated approach boosts therapeutic efficacy and highlights the potential of APM as a multifunctional agent for cancer therapy, paving the way for future clinical applications.

Heterojunction-Mediated Co-Adjustment of Band Structure and Valence State for Achieving Selective Regulation of Semiconductor Nanozymes

Improving reaction selectivity is the next target for nanozymes to mimic natural enzymes. Currently, the majority of strategies in this field are exclusively applicable to metal-organic-based or organic-based nanozymes, while limited in regulating metal oxide-based semiconductor nanozymes. Herein, taking semiconductor Co3O4 as an example, a heterojunction strategy to precisely regulate nanozyme selectivity by simultaneously regulating three vital factors including band structure, metal valence state, and oxygen vacancy content is proposed. After introducing MnO2 to form Z-scheme heterojunctions with Co3O4 nanoparticles, the catalase (CAT)-like and peroxidase (POD)-like activities of Co3O4 can be precisely regulated since the introduction of MnO2 affects the position of the conduction bands, preserves Co in a higher oxidation state (Co3+), and increases oxygen vacancy content, enabling Co3O4-MnO2 exhibit improved CAT-like activity and reduced POD-like activity. This study proposes a strategy for improving reaction selectivity of Co3O4, which contributes to the development of metal oxide-based semiconductor nanozymes.

A stimuli-responsive drug delivery system based on konjac glucomannan, carboxymethyl chitosan and mesoporous polydopamine nanoparticles

A stimuli-responsive drug delivery system is developed for controlled delivery of curcumin (Cur) and chemo-photothermal therapy of breast cancer (BC). Cur is first loaded into mesoporous polydopamine nanoparticles (mPDA NPs) by π-π stacking, and then the Cur loaded mPDA NPs (mPDA NPs@Cur) are encapsulated in the hydrogels prepared through the crosslinking of oxidized konjac glucomannan (oxKGM) and carboxymethyl chitosan (CMCS). Owing to the pH-sensitivity of the hydrogels and the outstanding photothermal conversion capability of mPDA NPs, the release of Cur from the hydrogels can be greatly accelerated in acidic media upon near infrared (NIR) irradiation. Cytotoxicity assay indicates that the hydrogels have significant cytotoxicity against murine breast tumor cell 4 T1 while the drug-free hydrogels (oxKGM/CMCS/mPDA NPs) show good biocompatibility. In addition, the hyperthermia generated upon NIR irradiation can lead to the apoptosis of cancer cells, achieving chemo-photothermal combination therapy of BC. Release kinetics study reveals that the release of Cur from the hydrogels follows zero-order model.

Plasmonic heating by indium tin oxide nanoparticles: spectrally enabling decoupled near-infrared theranostics

All-optical theranostic systems are sought after in nanomedicine, since they combine in a single platform therapeutic and diagnostic capabilities. Commonly in these systems the therapeutic and diagnostic/imaging functions are accomplished with plasmonic photothermal agents and luminescent nanoparticles (NPs), respectively. For maximized performance and minimized side effects, these two modalities should be independently activated, i.e., in a decoupled way, using distinct near infrared (NIR) wavelengths: a radiation window wherein photon-tissue interaction is reduced. Yet, to date, a fully decoupled NIR theranostics system is not available. Finding plasmonic NPs working in that range and without spectral overlap with the absorption and emission of state-of-the-art NIR luminescent NPs requires the development of new materials specifically designed for this purpose. To address this limitation, we herein present water-dispersible indium tin oxide (ITO) NPs whose surface plasmon resonance was tuned for exclusive operation in the third biological window (NIR-III, 1500-1800 nm). That leaves available the first and second biological windows, in which diagnostic tools are typically working. Both the microwave-assisted synthesis and the water-transfer protocol were optimized to obtain NPs with maximum light-to-heat conversion capabilities, owing to their small size and reduced aggregation in aqueous media. Proof-of-concept experiments showed that the lack of overlap between the absorption of ITO NPs and the absorption/emission of model near infrared luminescent species (the widely used Nd3+-doped NPs) is an asset when devising an all-optical theranostics platform. The obtained results set the stage for the development of a new generation of high-performance, all-optical theranostic systems with minimized side effects.

Nanoization of Technical Pesticides: Facile and Smart Pesticide Nanocapsules Directly Encapsulated through "On Site" Metal-Polyphenol Coordination Assembly for Improved Efficacy and Biosafety

Facile pesticide nanocapsules were successfully prepared by directly encapsulating the antisolvent precipitation of pesticides through instantaneous "on site" coordination assembly of tannic acid and Fe3+, avoiding tedious preparation, time consumption, and large amounts of organic solvents. The pesticide nanocapsules showed excellent resistance to ultraviolet photolysis and rainwater washing owing to the nanocapsule walls. The smart pesticide nanocapsules exhibited the controlled release of pesticides under multidimensional stimuli, such as acidic/alkaline pH, glutathione, H2O2, phytic acid, laccase, tannase, and sunlight, which were related to the physiological and natural environments of crops, pests, and pathogens. The tebuconazole nanocapsules not only enhanced the fungicidal activity against Fusarium graminearum and effective control efficacy in wheat powdery mildew through foliar spray and seed coating, but also improved the biosafety of target plant growth and nontarget organisms. The facile, smart, efficient, safe, and green pesticide nanocapsules using the universal strategy have broad application prospects in ecoagriculture.

Alternating Donor-Acceptor Ladder-Type Heteroarene for Efficient Photothermal Conversion via Boosting Non-Radiative Decay

The development of novel ladder-type conjugated molecules is crucial for advancing supramolecular chemistry and material science. In this study, we report a straightforward synthesis of new alternating donor-acceptor (D-A) ladder-type heteroarene, FCDTDPP, and demonstrate its application as photothermal agent for imaging and cancer therapy. FCDTDPP is constructed by vinylene bridge between cyclopentadithiophene (D) and diketopyrrolopyrrole (A) through intramolecular Friedel-Crafts type reaction. FCDTDPP exhibits unique combination of good molecular planarity, efficient intra-/intermolecular mixed D-A interactions, and local aromaticity. These features collectively contribute to its broad and intense absorptions with narrow band gap in red band of the spectra, coupled with multiple vibrational absorption feature, thereby enhancing non-radiative decay process and resulting in efficient photothermal conversion property. FCDTDPP and its nanoparticles (NPs) exhibit superior photothermal conversion performance and stability under 660 nm laser irradiation. Moreover, in vitro studies reveal that FCDTDPP NPs possess excellent biocompatibility, low cytotoxicity, and robust photothermal therapeutic efficacy, a finding further corroborated by preliminary in vivo experiments in tumor-bearing mice. This work charts a novel course for the molecular engineering of organic photothermal conversion systems, propelling relevant research forward.

A cuproptosis-based nanomedicine suppresses triple negative breast cancers by regulating tumor microenvironment and eliminating cancer stem cells

Cuproptosis is a new kind of cell death that depends on delivering copper ions into mitochondria to trigger the aggradation of tricarboxylic acid (TCA) cycle proteins and has been observed in various cancer cells. However, whether cuproptosis occurs in cancer stem cells (CSCs) is unexplored thus far, and CSCs often reside in a hypoxic tumor microenvironment (TME) of triple negative breast cancers (TNBC), which suppresses the expression of the cuproptosis protein FDX1, thereby diminishing anticancer efficacy of cuproptosis. Herein, a ROS-responsive active targeting cuproptosis-based nanomedicine CuET@PHF is developed by stabilizing copper ionophores CuET nanocrystals with polydopamine and hydroxyethyl starch to eradicate CSCs. By taking advantage of the photothermal effects of CuET@PHF, tumor hypoxia is overcome via tumor mechanics normalization, thereby leading to enhanced cuproptosis and immunogenic cell death in 4T1 CSCs. As a result, the integration of CuET@PHF and mild photothermal therapy not only significantly suppresses tumor growth but also effectively inhibits tumor recurrence and distant metastasis by eliminating CSCs and augmenting antitumor immune responses. This study presents the first evidence of cuproptosis in CSCs, reveals that disrupting hypoxia augments cuproptosis cancer therapy, and establishes a paradigm for potent cancer therapy by simultaneously eliminating CSCs and boosting antitumor immunity.

Hybrid Membrane Biomimetic Photothermal Nanorobots for Enhanced Chemodynamic-Chemotherapy-Immunotherapy

Glioblastoma multiforme (GBM) is a highly invasive and fatal brain tumor with a grim prognosis, where current treatment modalities, including postoperative radiotherapy and temozolomide chemotherapy, yield a median survival of only 15 months. The challenges of tumor heterogeneity, drug resistance, and the blood-brain barrier necessitate innovative therapeutic approaches. This study introduces a strategy employing biomimetic magnetic nanorobots encapsulated with hybrid membranes derived from platelets and M1 macrophages to enhance blood-brain barrier penetration and target GBM. The nanorobots encapsulate a polypyrrole/Fe3O4 nanocomplex (PPy@F) for photothermal therapy (PTT) and promote the Fenton reaction of Fe3O4 to generate chemodynamic therapy (CDT). Additionally, temozolomide and PD-L1 antibody (SNTSESF) act as chemotherapy drug and immune checkpoint inhibitor, respectively. The biomimetic design leverages the functional properties of cell membranes to improve the blood residence time and tumor targeting. The integration of PTT and CDT aims to transform "cold" tumors into "hot" tumors, thereby enhancing immunotherapeutic efficacy. This multifaceted approach, PTT, CT, CDT, and immune checkpoint blockade therapy, offers a promising strategy for the treatment of GBM.

Near-Infrared Photothermal Conversion by Isocorrole and Phlorin Derivatives

Photothermal therapy is a promising strategy for treating tumors and bacterial infections by using light irradiation to locally heat tissues. Metalloisoporphyrinoid materials have been investigated for their use as singlet oxygen photosensitizers for photodynamic therapy but remain underexplored as photothermal agents. Recently, two metallophlorin and two metalloisocorrole materials were found to have strong near-infrared absorbance, with low photoluminescent quantum yields, suggesting high rates of nonradiative decay. Here we demonstrate that when encapsulated into aggregated organic nanoparticles (a-Odots), these materials show high photothermal conversion efficiencies between 67.3 ± 8.4 and 75.7 ± 4.1%. When considered alongside their ability to generate singlet oxygen, these materials may show promise as agents for dual photothermal and photodynamic therapy.

Plasmonic Nanoparticles for Photothermal Therapy: Benchmarking of Photothermal Properties and Modeling of Heating at Depth in Human Tissues

Many different types of nanoparticles have been developed for photothermal therapy (PTT), but directly comparing their efficacy as heaters and determining how they will perform when localized at depth in tissue remains complex. To choose the optimal nanoparticle for a desired hyperthermic therapy, it is vital to understand how efficiently different nanoparticles extinguish laser light and convert that energy to heat. In this paper, we apply photothermal mass conversion efficiency (η m ) as a metric to compare nanoparticles of different shapes, sizes, and conversion efficiencies. We selected silica-gold nanoshells (AuNShells), gold nanorods (AuNRs), and gold nanostars (AuNStars) as three archetypal nanoparticles for PTT and measured the η m of each to demonstrate the importance of considering both photothermal efficiency and extinction cross section when comparing nanoparticles. By utilizing a Monte Carlo model, we further applied η m to model how AuNRs performed when located at tissue depths of 0-30 mm by simulating the depth penetration of near-infrared (NIR) laser light. These results show how nanoparticle concentration, laser power, and tissue depth influence the ramp time to a hyperthermic temperature of 43 °C. The methodology outlined in this paper creates a framework to benchmark the heating efficacy of different nanoparticle types and a means of estimating the feasibility of nanoparticle-mediated PTT at depth in the NIR window. These are key considerations when predicting the potential clinical impact in the early stages of nanoparticle design.

Design, synthesis, and characterization of an Ag-Bi-S-based multifunctional nanotheranostic platform

This paper reports an Ag-Bi-S-based nanotheranostic platform with an ingeniously designed heterostructure, an appropriate size, and good imaging and therapy performances. By comparing the fluorescence property and Bi element content, the optimal heterostructure was demonstrated to be Ag2S/Bi2S3 core/shell. The hydrophilic Ag2S/Bi2S3-PEG nanocrystals with hydrodynamic diameter of 37.56 nm exhibited near-infrared-II fluorescence, good CT imaging contrast, and a high photothermal conversion efficiency (38.4%), and have shown significant potential in the precision diagnosis and treatment of tumors.

Construction of a regulable chiral recognition platform based on the photothermal effect of popcorn-like gold nanoparticles/bovine serum albumin

Although the chiral recognition ability of nanomaterials is known to play a crucial role in the chiral discrimination of enantiomers, it remains challenging to precisely regulate the chiral recognition ability predictably and on demand. In this work, a regulable chiral recognition platform is designed based on the photothermal effect of popcorn-like gold nanoparticles (AuNPs)/bovine serum albumin (BSA). First, AuNPs with excellent chiral recognition ability are prepared for the discrimination of tyrosine (Tyr) enantiomers. Subsequently, AuNPs can be combined with BSA through the Au-S bond. The obtained AuNPs/BSA exhibits the opposite chiral recognition ability to AuNPs due to the inherent chirality of BSA. Interestingly, BSA can also be destroyed relying on the photothermal effect of AuNPs and the excitation of near-infrared (NIR) light. Therefore, the resulting AuNPs/BSA/NIR reversibly displays the same chiral recognition ability as AuNPs. A regulable chiral recognition platform is constructed for chiral discrimination of Tyr enantiomers, which can satisfy the purpose of predictable and on-demand regulation of the recognition ability of nanomaterials and might be a potential candidate for detection and therapy in vivo.

Numerical Simulation of Light to Heat Conversion by Plasmonic Nanoheaters

Plasmonic nanoparticles are widely recognized as photothermal conversion agents, i.e., nanotransducers or nanoheaters. Translation of these materials into practical applications requires quantitative analyses of their photothermal conversion efficiencies (η). However, the value of η obtained for different materials is dramatically influenced by the experimental setup and method of calculation. Here, we evaluate the most common methods for estimating η (Roper's and Wang's) and compare these with numerical estimates using the simulation software ANSYS. Experiments were performed with colloidal gold nanorod solutions suspended in a hanging droplet irradiated by an 808 nm diode laser and monitored by a thermal camera. The ANSYS simulations accounted for both heating and evaporation, providing η values consistent with the Wang method but higher than the Roper approach. This study details methods for estimating the photothermal efficiency and finds ANSYS to be a robust tool where experimental constraints complicate traditional methods.

Synergistic effects of Au nanoparticles in SiO2@Au@Polyaniline system for improved photothermal performance

A SiO2@Au@Polyaniline (SiO2@Au@PAN) system has been successfully fabricated leveraging the synergistic effects of gold nanoparticles (AuNPs) to realize enhanced photothermal performance. The SiO2@Au@PAN exhibited strong near-infrared (NIR) absorbance, excellent photothermal conversion efficiency, good dispersibility, and outstanding photostability. The SiO2 nanospheres as the template provided numerous binding sites for coating of AuNPs. Subsequently, aniline was grafted onto SiO2 to form PAN, which further facilitated the growth of AuNPs. The high efficiency of electron transfer from PAN to AuNPs was utilized to enhance the photothermal performance, resulting in a photothermal conversion efficiency of 41.47%. Additionally, the effects of SiO2 with different sizes on the anchoring of AuNPs and the impact of aniline with varying concentrations on the morphology and photothermal properties of the materials were investigated. Finally, we verified the photothermal therapeutic (PTT) effect of SiO2@Au@PAN at cellular level, with results demonstrating effective destruction of cancer cells. This work may provide an approach for establishing a multi-component PTT platform based on the synergistic effects of AuNPs, holding significant potential for biomedical and biochemistry applications.

Polydopamine-assisted decoration of silver nanoparticles on gold nanorods for photothermal and chemical antimicrobial applications

AuNRs@PDA@AgNPs were prepared by assembling AgNPs on AuNRs with the assistance of PDA, realizing synergistic photothermal and chemical sterilization.

Manganese-coordinated nanoparticle with high drug-loading capacity and synergistic photo-/immuno-therapy for cancer treatments

Stimulator of interferon genes (STING) agonists have shown promise in cancer treatment by stimulating the innate immune response, yet their clinical potential has been limited by inefficient cytosolic entry and unsatisfactory pharmacological activities. Moreover, aggressive tumors with "cold" and immunosuppressive microenvironments may not be effectively suppressed solely through innate immunotherapy. Herein, we propose a multifaceted immunostimulating nanoparticle (Mn-MC NP), which integrates manganese II (Mn2+) coordinated photosensitizers (chlorin e6, Ce6) and STING agonists (MSA-2) within a PEGylated nanostructure. In Mn-MC NPs, Ce6 exerts potent phototherapeutic effects, facilitating tumor ablation and inducing immunogenic cell death to elicit robust adaptive antitumor immunity. MSA-2 activates the STING pathway powered by Mn2+, thereby promoting innate antitumor immunity. The Mn-MC NPs feature a high drug-loading capacity (63.42 %) and directly ablate tumor tissue while synergistically boosting both adaptive and innate immune responses. In subsutaneous tumor mouse models, the Mn-MC NPs exhibit remarkable efficacy in not only eradicating primary tumors but also impeding the progression of distal and metastatic tumors through synergistic immunotherapy. Additionally, they contribute to preventing tumor recurrence by fostering long-term immunological memory. Our multifaceted immunostimulating nanoparticle holds significant potential for overcoming limitations associated with insufficient antitumor immunity and ineffective cancer treatment.

Iron-based magnetic nanocomplexes for combined chemodynamic and photothermal cancer therapy through enhanced ferroptosis

Chemodynamic therapy (CDT) guided by Fenton chemistry and iron-containing materials can induce ferroptosis as a prospective cancer treatment method, but the inefficient Fe3+/Fe2+ conversion restricts the monotherapeutic performances. Here, an iron-based nanoplatform (Fe3O4-SRF@FeTA) including a magnetic core and a reductive film is developed for combined CDT and photothermal therapy (PTT) through ferroptosis augmentation. The inner iron oxide core serves as a photothermal transducer, a magnet-responsive module, and an iron reservoir for CDT. The coated Fe3+-tannic acid film (FeTA) provides extra iron and reductants for Fe3+/Fe2+ conversion acceleration, and functions as a door keeper for the pH- and light-responsive release of the embedded ferroptosis inducer sorafenib (SRF). The in vitro results demonstrate that the iron-based nanocomplexes promote the production of lipid peroxide through the amplified Fenton activity, and downregulate glutathione involved in lipid peroxide repair system through the responsively released SRF. Upon accumulation in tumor by magnetic targeting and sequential laser irradiation locoregionally, Fe3O4-SRF@FeTA nanocomplexes present prominent in vivo anticancer efficacy by leveraging PTT and CDT-enhanced ferroptosis.

Strong absorption in ultra-wide band by surface nano engineering of metallic glass

Broadband light absorption is important for applications such as infrared detectors, solar energy collectors, and photothermal conversion. We propose a facile and common strategy to fabricate light absorbers with strong ultra-wideband absorption. Due to their excellent thermoplastic forming ability, metallic glasses could be patterned into finely arranged nanowire arrays, which show extremely low reflectivity (∼0.6%) in the visible and near-infrared regimes, and a low reflectivity (∼15%) in the mid-infrared regime as caused by multiscale nano spacing, multiple reflections, and plasmonic behavior. The strong absorption at surfaces with nanowires provides excellent photothermal conversion properties. The photothermal properties show that a surface with nanowires can be rapidly heated up to ∼160 °C at a rate of 28.75 °C/s, which is 30 times higher than smooth surfaces. Meanwhile, a surface with nanowires shows a high photothermal conversion efficiency (ηPT = 56.36%). The fabricated metallic glass absorbers exhibit adaptability as they can be easily formed into various complex shapes and meet the requirements under harsh conditions. The outcomes of our research open the door to manufacturing high-performance absorbers for applications in photothermal electric power generation, desalination, and photodetectors.

A Phthalimide-Functionalized Heptamethine Cyanine Dye for Tumor-Targeted Photothermal Therapy

BACKGROUND

A phthalimide-functionalized heptamethine cyanine dye, named Ph790H, is used for targeted photothermal cancer therapy in vivo. We highlight that the chemical structure of Ph790H is newly designed and synthesized for the first time in this study.

OBJECTIVES

By possessing a rigid chloro-cyclohexenyl ring in the heptamethine cyanine backbone, the bifunctional near-infrared (NIR) fluorescent dye Ph790H can be preferentially accumulated in tumor without the need for additional targeting ligands, which is defined as the "structure-inherent tumor targeting" concept.

METHODS

The phototherapeutic effect of Ph790H is evaluated in HT-29 human colorectal cancer xenografts to be used as a cancer-targeting photothermal agent.

RESULTS

The results reveal that the Ph790H shows enhanced tumor accumulation in HT-29 xenografts 48 h post-injection with a high tumor-to-background ratio. After determination of the optimal timing for photothermal therapy (PTT), the HT-29 tumor-possessing nude mice pretreated with Ph790H are subsequently irradiated with an 808 nm NIR laser for 5 min. The tumor-targeted PTT treatment can efficiently inhibit the tumor development compared with that of control groups. Moreover, no tumor regrowth or Ph790H-induced mortality occurs after the treatment of Ph790H and laser irradiation during a period of monitoring.

CONCLUSIONS

Therefore, this work demonstrates that the bifunctional phototheranostic agent Ph790H can be utilized for targeted cancer imaging and fluorescence-guided phototherapy simultaneously.

Near-Infrared-II-Activated Transition Metal(II)-Coordinated Ligand Radical Primes Robust Anticancer Immunity

Photoactivatable metallodrugs combining tumor cell eradication and immune stimulation hold immense promise for targeted cancer therapy. However, limitations such as oxygen dependence, narrow visible light responsiveness, and poor immunogenicity hinder their efficacy in deep solid tumors with hypoxic and immunosuppressive microenvironments. Herein, we present a novel design strategy for transition metal(II)-coordinated ligand radicals exhibiting intense near-infrared-II (NIR-II) absorption, unique endoplasmic reticulum-targeting capability, and oxygen-independent photothermal performance, effectively addressing these constraints. Proof-of-concept results demonstrate the potent efficacy of our cobalt(II)-coordinated ligand radical (BPDP-Co) in inducing highly immunogenic pyroptosis in tumor cells under both normoxic and severe hypoxic conditions upon 1064 nm laser irradiation. This NIR-II activation triggers the release of damage-associated molecular patterns (DAMPs) and proinflammatory cytokines, fueling a robust antitumor immune response. In vivo studies demonstrate that treatment with BPDP-Co/NIR-II significantly inhibited 4T1 tumor growth in BALB/c mice with a high inhibitory rate of 85.7%, highlighting its therapeutic potential in tumor immunotherapy.

Bio-friendly multi-stimuli responsive α-CD polymer-gated mesoporous carbon nanoherbicides for enhanced paraquat delivery

INTRODUCTION

Weeds seriously affect crop yield in global agricultural production. Paraquat (PQ), as one of low cost and highly effective herbicide, is forbidden or severely restricted in production and sales owing to its lethal toxicity to humans. Creating an efficient and bio-friendly PQ formulation is crucial to facilitate the open use of PQ in world's agriculture.

OBJECTIVES

This study aims to construct one intelligent and bio-friendly mesoporous carbon nanoparticles (MCN) nanoherbicides coated with α-CD polymer (CDP) gatekeepers.

METHODS

MCN was prepared through the low-concentration hydrothermal way, calcined and carbonized. PEG stalks were immobilized on MCN surface by amidation reaction. The PQ was trapped in the MCN pores via physical diffusion adsorption and the robust π-π effects between electron-deficient PQ and electron-rich MCN. CDP gatekeepers were fastened via host-guest effects between the chamber of α-CD units and PEG stalks.

RESULTS

The PQ-loaded MCN-PEG@CDP nanoherbicides integrated with multi-stimuli responses to amylase, elevated temperature under sunlight, and competitors at leaf interface to control the PQ release for efficient weed control, while appeared low PQ leakage under the simulated human gastric or intestinal conditions, low cytotoxicity to human normal cells in vitro, and high mouse survival rate in vivo. Even through the nanoherbicides inevitably contact with water or intake by beneficial insects, they appear good biosafety on zebrafish (D. rerio) and honeybees (Apis mellifera L.).

CONCLUSION

The as-prepared nanoherbicides have high herbicidal efficacy and low risks to non-target species, and could promote the open use of PQ in agriculture.

Dual-Targeted Assembled Nanodrugs for Near-Infrared Photothermal Immunotherapy of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is known for its poor prognosis and aggressive behavior, being highly prone to recurrence and metastasis, and currently has limited effective treatment options. Photothermal therapy (PTT) is an emerging, minimally invasive, low-drug-resistance, and precisely controllable therapeutic method for cancer treatment, offering hope to break through the bottleneck in TNBC therapy. The antitumor efficiency of PTT is predominantly contingent upon the performance of the photothermal drugs. Therefore, there is an urgent need to develop photothermal drugs that not only have excellent photothermal conversion efficiency but also possess strong tumor-targeting capabilities and good biosafety. Here, we have developed a tumor-targeted photothermal agent with near-infrared (NIR) absorption capability based on the strategy of biomolecular assembly, utilizing biliverdin manganese complexes (MnBV) and amphiphilic phospholipid-polymer conjugates (DSPE-PEG and DSPE-PEG-cKNGRE). This photothermal assembled drug exhibits a uniform size, good stability, and ideal photothermal conversion efficiency. In the 4T1 tumor-bearing mouse model of TNBC, it shows good tumor dual-targeting capabilities and a significant drug enrichment performance. While ablating the primary tumor, PTT further stimulates the maturation of dendritic cells (DCs), enhancing the infiltration of T lymphocytes into the spleen and tumor, thus reshaping the immune microenvironment of TNBC and thereby effectively inhibiting tumor metastasis and recurrence. The developed photothermal assembled drug provides an innovative candidate treatment paradigm for TNBC, offering the potential to advance precise, targeted, and safe therapy for highly invasive and aggressive malignancies.

Leveraging Femtosecond Laser Ablation for Tunable Near-Infrared Optical Properties in MoS2-Gold Nanocomposites

Transition metal dichalcogenides (TMDCs), particularly molybdenum disulfide (MoS2), have gained significant attention in the field of optoelectronics and photonics due to their unique electronic and optical properties. The integration of TMDCs with plasmonic materials allows to tailor the optical response and offers significant advantages for photonic applications. This study presents a novel approach to synthesize MoS2-Au nanocomposites utilizing femtosecond laser ablation in liquid to achieve tunable optical properties in the near-infrared (NIR) region. By adjusting ablation and fragmentation protocols, we successfully synthesize various core-shell and core-shell-satellite nanoparticle composites, such as MoS2/MoSxOy, MoSxOy/Au, and MoS2/MoSxOy/Au. UV-visible absorption spectroscopy unveils considerable changes in the optical response of the particles depending on the fabrication regime due to structural modifications. Hybrid nanoparticles exhibit enhanced photothermal properties when subjected to NIR-I laser irradiation, demonstrating potential benefits for selective photothermal therapy. Our findings underscore that the engineered nanocomposites not only facilitate green synthesis but also pave the way for tailored therapeutic applications, highlighting their role as promising candidates in the field of nanophotonics and cancer treatment.

4T1 Cell Membrane-Coated Pdots with NIR-II Absorption and Fluorescence Properties for Targeted Phototheranostics of Breast Tumors

Designing highly biocompatible organic semiconducting conjugated polymer dots (Pdots) with bright fluorescence and superior absorption properties in the second near-infrared window (NIR-II: 1000-1700 nm) remains a huge challenge for tumor phototheranostics. In this study, we constructed 4T1 cell membrane-coated m-PBTQ4F Pdots (CPdots) with enhanced NIR-II photoacoustic (PA) and fluorescence (FL) imaging capability for NIR-II photothermal therapy (PTT) of breast tumors. Our findings demonstrated that CPdots could specifically target breast tumors, leading to enhanced tumor accumulation after systemic administration in living mice. In addition, CPdots can not only serve as contrast agents for NIR-II PA and FL imaging for improved breast tumor detection but also generate more cytotoxic heat to improve PTT efficacy. Therefore, this pilot study opens an option avenue for developing new NIR-II Pdots with homologous targeting capability for enhanced phototheranostics of breast tumors.

Synergistic Effect in Hybrid Plasmonic Conjugates for Photothermal Applications

Photothermal conversion efficiency (η) plays a crucial role in selecting suitable gold nanoparticles for photothermal therapeutic applications. The photothermal efficiency depends on the material used for the nanoparticles as well as their various parameters, such as size and shape. By maximizing the light-to-heat conversion efficiency (η), one can reduce the concentration of nanoparticle drugs for photothermal cancer treatment and apply lower laser power to irradiate the tumor. In our study, we explored a new hybrid plasmonic conjugate for theranostic (therapy + diagnostic) applications. We conjugated PEG-functionalized 20 nm gold nanospheres with cyanine IR dyes via a PEG linker. The resulting conjugates exhibited significantly enhanced photothermal properties compared with bare nanoparticles. We experimentally showed that a proposed new hybrid plasmonic conjugate can achieve almost four times larger conversion efficiency (47.7%) than 20 nm gold nanospheres (12%). The enhanced photothermal properties of these gold conjugates can provide the required temperature for the photothermal treatment of cancer cells with lower concentrations of gold nanoparticles injected in the body as well as with lower applied incident laser power density. Moreover, the improved photothermal properties of the conjugates can be explained by a synergistic effect that has not been observed in the past. This effect results from the coupling between the metal nanosphere and the organic dye.

Antibacterial and anti-biofilm activities of gold-curcumin nanohybrids and its polydopamine form upon photo-sonotherapy of Staphylococcus aureus infected implants: In vitro and animal model studies

Implant-related infections are among the major post-surgery problems, and treatment of these infections is challenging due to the formation of biofilms by microorganisms such as Staphylococcus aureus. Herein, a novel gold-curcumin nanohybrid (GCNH) was synthesized for the first time and characterized. GCNH had a band gap energy of 2.41 eV, a zeta potential of -15 mV, and comprised uniform spherical particles with a mean diameter of 8 ± 2 nm. The biological macromolecule of polydopamine was then coated on GCNH to prepare a gold-curcumin-polydopamine nanohybrid (GCDNH). The nanohybrids were employed as novel dual photo-sonosensitizers for bacterial eradication by near-infrared (NIR) light and ultrasound (US) irradiations. GCNH and GCDNH represented photothermal conversion efficiencies of 26 and 32 %, respectively, and GCDNH represented a hemolysis rate of 2.3 % under both near-infrared (NIR) light and ultrasound (US) irradiations. NIR light and US irradiations (photo-sonotherapy) of Staphylococcus aureus using GCDNH depicted anti-bacterial and anti-biofilm efficiencies of 98 and 99 %, respectively, in synergistic manners, which are higher or as high as other sensitizers reported previously. The mechanism of photo-sonotherapy was related to generation of high levels of reactive oxygen species (ROS), and protein and nucleic acid leakages. In an in vivo infection model, NIR light and US irradiations annihilated Staphylococcus aureus on GCDNH-covered implants with high efficiency, without causing damage to normal tissues.

Biodegradable ICG-Conjugated Germanium Nanoparticles for In Vivo Near-Infrared Dual-Modality Imaging and Photothermal Therapy

Theranostics, by integrating diagnosis and therapy on a single platform, enables real-time monitoring of tumors during treatment. To improve the accuracy of tumor diagnosis, the fluorescence and photoacoustic imaging modalities can complement each other to achieve high resolution and a deep penetration depth. Despite the superior performance, the biodegradability of theranostic agents plays a critical role in enhancing nanoparticle excretion and reducing chronic toxicity, which is essential for clinical applications. Herein, we synthesize biocompatible and biodegradable indocyanine green (ICG)-conjugated germanium nanoparticles (GeNPs) and investigate their biodistributions in nude mice and 4T1 tumor models after intravenous injections using near-infrared (NIR) dual-modality fluorescence and photoacoustic imaging. The ICG-conjugated GeNPs have strong NIR absorption due to the NIR-absorbing ICG and Ge in combination, emit strong NIR fluorescence due to the multilayered ICG coatings, and exhibit very low in vitro and in vivo toxicity. After tail vein injections, the ICG-conjugated GeNPs mainly accumulate in the liver and spleen as well as the tumor with the help of the enhanced permeability and retention effect. The tumor's fluorescence signal is much stronger than that of the control group injected with pure ICG solution, as the GeNPs can function as biodegradable carriers for efficiently delivering the ICG molecules to the tumor. Lastly, the ICG-conjugated GeNPs accumulated in the tumor can also be utilized for photothermal treatment under NIR laser irradiation, after which the tumor volume almost diminishes after 14 days. The experimental findings in this work demonstrate that the ICG-conjugated GeNPs are promising theranostic agents with exceptional biodegradability for in vivo NIR dual-modality imaging and photothermal therapy.

Calixarene-coated gold nanorods as robust photothermal agents

Gold nanorods (AuNRs) hold considerable promise for their use in biomedical applications, notably in the context of photothermal therapy (PTT). Yet, their anisotropic nature presents a notable hurdle. Under laser irradiation, these structures are prone to deformation, leading to changes in their optical and photothermal properties over time. To overcome this challenge, an efficient strategy involving the use of calix[4]arene-tetradiazonium salts for stabilizing AuNRs has been implemented. These molecular platforms are capable of irreversible grafting onto surfaces through the reduction of their diazonium groups, thereby resulting in the formation of exceedingly robust organic monolayers. This innovative coating strategy not only ensures enduring stability but also facilitates conjugation of AuNRs. This study showcases the superiority of these fortified AuNRs over conventional counterparts, notably exhibiting exceptional resilience even under sustained laser exposure in the context of PTT. By bolstering the stability and reliability of AuNRs in PTT, our approach holds the potential to drive significant advancements in the field.

Assembly-enhanced indocyanine green nanoparticles for fluorescence imaging-guided photothermal therapy

The development of theranostic agents that offer complete biocompatibility, coupled with enhanced diagnostic and therapeutic performance, is crucial for fluorescence imaging-guided photothermal therapy in anti-tumor applications. However, the fabrication of nanotheranostics meeting the aforementioned requirements is challenged by concerns regarding biosafety and limited control over construction. Herein, we reported a class of fluorescence imaging-guided photothermal theranostic nanomaterials that are composed of amino acid derivatives and clinically used small photoactive indocyanine green molecules. Through manipulation of noncovalent interactions, these binary building blocks can co-assemble into nanoparticles in a tunable manner. Significantly, such construction not only maintained the fluorescence properties of photoactive molecules, but also enhanced their stability to overcome barriers from photodegradation and complex physiological conditions. These collective features integrated their precise anti-tumor applications, including fluorescence imaging diagnosis and photothermal ablation therapy. This study reported a class of nanotheranostics characterized by biocompatibility, adjustable construction, and robust stability, which are beneficial for the clinical translation of fluorescence imaging-guided photothermal therapy against tumors.

Highly Branched Au Superparticles as Efficient Photothermal Transducers for Optical Neuromodulation

Precise neuromodulation is critical for interrogating cellular communication and treating neurological diseases. Nanoscale transducers have emerged as effective interfaces to exert photothermal effects and modulate neural activities with a high spatiotemporal resolution. Ideal materials for this application should possess strong light absorption, high photothermal conversion efficiency, and great biocompatibility for clinical translation. Here, we show that the structurally designed 3D Au superparticles with a highly branched morphology can be promising candidates for nongenetic and remote neuromodulation. The structure-induced blackbody-like absorption endows Au superparticles with photothermal conversion efficiency over 90%, much higher than that of conventional Au nanorods. With the biocompatible polydopamine ligands, Au superparticles can be readily interfaced with primary mouse hippocampal neurons and other cells and can photostimulate or inhibit their activities in both cell networks or with a single-cell resolution. These findings highlight the importance of structural designs as powerful tools to promote the performance of plasmonic materials in neuromodulation and related research of neuroscience and neuroengineering.

Interband and Intraband Hot Carrier-Driven Photocatalysis on Plasmonic Bimetallic Nanoparticles: A Case Study of Au-Cu Alloy Nanoparticles

Photoexcited nonthermal electrons and holes in metallic nanoparticles, known as hot carriers, can be judiciously harnessed to drive interesting photocatalytic molecule-transforming processes on nanoparticle surfaces. Interband hot carriers are generated upon direct photoexcitation of electronic transitions between different electronic bands, whereas intraband hot carriers are derived from nonradiative decay of plasmonic electron oscillations. Due to their fundamentally distinct photogeneration mechanisms, these two types of hot carriers differ strikingly from each other in terms of energy distribution profiles, lifetimes, diffusion lengths, and relaxation dynamics, thereby exhibiting remarkably different photocatalytic behaviors. The spectral overlap between plasmon resonances and interband transitions has been identified as a key factor that modulates the interband damping of plasmon resonances, which regulates the relative populations, energy distributions, and photocatalytic efficacies of intraband and interband hot carriers in light-illuminated metallic nanoparticles. As exemplified by the Au-Cu alloy nanoparticles investigated in this work, both the resonant frequencies of plasmons and the energy threshold for the d-to-sp interband transitions can be systematically tuned in bimetallic alloy nanoparticles by varying the compositional stoichiometries and particle sizes. Choosing photocatalytic degradation of Rhodamine B as a model reaction, we elaborate on how the variation of the particle sizes and compositional stoichiometries profoundly influences the photocatalytic efficacies of interband and intraband hot carriers in Au-Cu alloy nanoparticles under different photoexcitation conditions.

Plasmonic semi shells derived from simultaneous in situ gold growth and anisotropic acid etching of ZIF-8 for photothermal ablation of metastatic breast tumor

Open nanoshells such as nanobowls or nanocups collectively described as 'semi shells' have unique plasmonic properties due to their lack of symmetry. So far, their fabrication was based on multistep and laborious methods such as solid state sputter coating or selective deposition/etching using sacrificial templates. In this work, we report a rapid one step colloidal synthetic protocol for PEGylated semi-shell (SS) fabrication by simultaneous facet specific anisotropic chemical etching of rhombic dodecahedral ZIF-8 and heterogenous nucleation & growth of gold. The SS possesses a strong localized surface plasmon resonance in the near-infrared region, which is retained after surface passivation with polyethylene glycol and subsequent cryopreservation for extended shelf-life. Freshly reconstituted PEGylated SS was found to be safe & non-toxic in healthy C57BL/6 mice post intravenous administration. The PEGylated SS displayed significant photothermal efficiency of ~37% with 808 nm laser irradiation. Preclinical assessment of intra-tumoral photothermal efficacy indicated complete remission of primary breast tumor mass with insignificant metastasis to vital organs in 4T1 FL2 tumor bearing CD1 nude mice. Further, PEGylated SS mediated photothermal therapy also yielded morbidity free survivael of 75% for up to 90 days, indicating their potential to significantly improve outcomes in advanced breast tumors.

A photothermal effect-based chiral sensor for chiral discrimination and sensitive detection

Chiral analysis with simple devices is of great importance for analytical chemistry. Based on the photothermal (PT) effect, a simple chiral sensor with a portable laser device as the light source and a thermometer as the detection tool was developed for the chiral recognition of tryptophan (Trp) isomers and the sensitive sensing of one isomer (L-Trp). Gold nanorods (GNRs), which have outstanding photo-thermal conversion ability due to their localized surface plasma resonance (LSPR) effect, are used as PT reagents, and biomacromolecules bovine serum albumin (BSA) are used as natural chiral sources, and thus, GNRs@BSA was obtained through Au-S bonds. The resultant GNRs@BSA displays higher affinity toward L-Trp than D-Trp owing to the inherent chirality of BSA. Under the irradiation of near-infrared (NIR) light, the temperature of GNRs@BSA//L-Trp is greatly lower than that of GNRs@BSA//D-Trp due to its greatly decreased thermal conductivity, and thus chiral discrimination of Trp isomers can be achieved. In addition, the developed PT effect-based chiral sensor can be used for sensitive detection of L-Trp, and the linear range and limit of detection (LOD) are 1 μM-10 mM and 0.43 μM, respectively.

Laser-synthesized plasmonic HfN-based nanoparticles as a novel multifunctional agent for photothermal therapy

Hafnium nitride nanoparticles (HfN NPs) can offer appealing plasmonic properties at the nanoscale, but the fabrication of stable water-dispersible solutions of non-toxic HfN NPs exhibiting plasmonic features in the window of relative biological transparency presents a great challenge. Here, we demonstrate a solution to this problem by employing ultrashort (femtosecond) laser ablation from a HfN target in organic solutions, followed by a coating of the formed NPs with polyethylene glycol (PEG) and subsequent dispersion in water. We show that the fabricated NPs exhibit plasmonic absorption bands with maxima around 590 nm, 620 nm, and 650 nm, depending on the synthesis environment (ethanol, acetone, and acetonitrile, respectively), which are largely red-shifted compared to what is expected from pure HfN NPs. The observed shift is explained by including nitrogen-deficient hafnium nitride and hafnium oxynitride phases inside the core and oxynitride coating of NPs, as follows from a series of structural characterization studies. We then show that the NPs can provide a strong photothermal effect under 808 nm excitation with a photothermal conversion coefficient of about 62%, which is comparable to the best values reported for plasmonic NPs. MTT and clonogenic assays evidenced very low cytotoxicity of PEG-coated HfN NPs to cancer cells from different tissues up to 100 μg mL-1 concentrations. We finally report a strong photothermal therapeutic effect of HfN NPs, as shown by 100% cell death under 808 nm light irradiation at NP concentrations lower than 25 μg mL-1. Combined with additional X-ray theranostic functionalities (CT scan and photon capture therapy) profiting from the high atomic number (Z = 72) of Hf, plasmonic HfN NPs promise the development of synergetically enhanced modalities for cancer treatment.

Site-Specific Location of Black Phosphorus Quantum Dot Cluster-Based Nanocomplexes for Synergistic Ion Channel Therapy and Hypoxic Microenvironment Activated Chemotherapy

The spatiotemporal regulation of ion transport in living cell membrane channels has immense potential for providing novel therapeutic approaches for the treatment of currently intractable diseases. So far, most strategies suffer from uncontrolled ion transport and limited tumor therapy effects. On the premise of low toxicity to healthy tissues, enhancing the degree of ion overloading and the effect of tumor treatment still remains a challenging concern. Herein, an innovative strategy for synergistic ion channel therapy and hypoxic microenvironment activated chemotherapy is proposed. Biocompatible AQ4N/black phosphorus quantum dot clusters@liposomes (AQ4N/BPCs@Lip) nanocomplexes are site-specifically immobilized on the living cell membrane by a metabolic labeling strategy, eliminating the need for modifying or genetically encoding channel structures. Ascribing to the localized temperature increase of BPCs under NIR light irradiation, Ca2+ overinflux can be remotely controlled and the overloading degree was increased; moreover, the local released AQ4N can only be activated in the tumor cell, while it has no toxicity to normal cells. Compared with single intracellular Ca2+ overloading, the tumor cell viabilities decrease 2-fold with synergetic Ca2+ overloading-induced ion channel therapy and hypoxic microenvironment activated chemotherapeutics. Our study demonstrates the example of a remote-controlled ion influx and drug delivery system for tumor therapy.

Development of folate-conjugated polypyrrole nanoparticles incorporated with nitrogen-doped carbon quantum dots for targeted bioimaging and photothermal therapy

PPy nanoparticles are widely employed as PTT agents, because of their exceptional near-infrared absorption properties. Nonetheless, the efficacy of PTT with PPy nanoparticles is hindered by a challenge, specifically, a lack of precise targeting. In this study, a PTT imaging agent was developed by combining NCQDs having bright green fluorescent properties with PPy nanoparticles along with the masking of folic acid to overcome the challenge of targeting. The synthesized PPy:NCQDs:FA nanocomposite, characterized by extraordinary photothermal property, was utilized for imaging of folate receptor positive (FA+) MCF-7 cancer cells through the emission of green fluorescence by NCQDs incorporated within the nanocomposite. Additionally, these nanoparticles demonstrated a good level of cell viability, exceeding 82 %, even at a concentration of 600 μg mL-1. Even the in vivo toxicity inspection of the nanocomposite exemplified no observed acute toxicity at experimental dosages of 1 and 3 mg per kg body weight. By subjecting MCF-7 cells, inoculated with 100 μg mL-1 of nanocomposite, to NIR laser irradiation for 5 min, a significant decline in cell viability was witnessed, establishing the photothermal therapeutic potency of the nanocomposite. The death of cancer cells induced by nanocomposite was verified through MTT assay, imaging of cells by NCQDs alone, with nanocomposite, and by live/dead cell Calcein AM/PI staining assay. Quantification of induced apoptosis post-laser treatment is conducted through staining with Annexin V-FITC/PI. These findings establish potential use of PPy:NCQDs:FA nanocomposite as versatile theranostic agents, capable of targeted bioimaging and treatment for cancer cells exhibiting folate receptors.

Facile Surface Modification with Croconaine-Functionalized Polymer on Polypropylene for Antifouling and NIR-Light-Mediated Photothermal Sterilization

Biomedical-device-associated infection (BAI) is undoubtedly a major concern and a serious challenge in modern medicine. Therefore, the development of biomedical materials that are capable of resisting or killing bacteria is of great importance. In this work, a croconaine-functionalized polymer with antifouling and near-infrared (NIR) photothermal bactericidal properties was prepared and facilely modified on polypropylene (PP) to combat medical device infections. Croconaine dye is elaborately modified as a "living" initiator, termed CR-4EBiB, for preparing amphiphilic block polymers by atom transfer radical polymerization (ATRP). In the formed polymer coating, the hydrophobic block can strongly adhere to the surface of the PP substrate, whereas the hydrophilic block is located on the outer layer by solvent-induced resistance to bacterial adhesion. Under the irradiation of an NIR laser (808 nm), the croconaine dye in the coating achieved maximum conversion of light to heat to effectively kill E. coli, S. aureus, and methicillin-resistant Staphylococcus aureus (MRSA). This work provides a facile and promising strategy for the development of implantable antibacterial biomedical materials.