Quantitative Comparison of the Light-to-Heat Conversion Efficiency in Nanomaterials Suitable for Photothermal Therapy

Gold-Cerium bimetallic Star-Shaped nanoplatform for synergistic tumor therapy with nanozyme Catalytic/Photothermal/Chemotherapy

A gold-cerium bimetallic asteroid nanoplatform (CeO2@GNSs/Myr-HA) was obtained by electrostatically adsorbing ultra-small cerium dioxide (CeO2) onto gold nanostars (GNSs) and further loading myricetin (Myr) and hyaluronic acid (HA). This nanoplatform exhibited three types of enzymatic properties-that is, GOD (glucose-oxidase), POD (peroxidase) and GSH-Ox (glutathione oxidase) mimicking catalytic activities. These enzymatic properties work together to effectively induce apoptosis in tumor cells. HA targets the CD44 receptor, which is located on the surface of tumor cells, leading to the further release of CeO2@GNSs/Myr into the cytosol. Myr functions as a chemical agent that inhibits the expression of vascular endothelial growth factor (VEGF), thereby suppressing tumor cell angiogenesis via the p38/MAPK signaling pathway. When exposed to light radiation of 808-nm wavelength, the nanomaterials aggregated at the tumor site efficiently absorbed photons and converted them into thermal energy, enabling the precise thermal ablation of the malignancy. Moreover, CeO2@GNSs/Myr-HA-as a multifunctional nanoplatform combining nanozyme catalytic therapy with photothermal therapy and chemotherapy-demonstrated the synergistic effect of effectively suppressing cancer cell proliferation and enhancing tumor ablation.

Differential evolution-optimized gold nanorods for enhanced photothermal conversion

Noble metallic nanoparticles (NPs) have shown great potential in the field of sustainable energy. Gold nanorods (AuNRs), known for their size-dependent optical and electrical characteristics, are strong candidates for various applications, particularly in solar energy conversion. Additionally, AuNRs are well-established nanomaterials in precision medicine. In this paper, we optimize the shape and size of AuNRs to maximize light-to-heat conversion based on a validated theoretical model. Utilizing the Differential Evolution (DE) algorithm, a robust metaheuristic optimization approach, we calculated the optimal size and shape of AuNRs for selected wavelengths. The aspect ratio (AR), defined as the ratio of the diameter to the length of the AuNRs, was a key parameter in the optimization process. The optimization results reveal that for shorter wavelengths, near-spherical AuNRs (AR of 0.71 and 0.75) demonstrate the highest efficiency, while for longer wavelengths, more elongated AuNRs (AR of 0.24 and 0.17) outperform others. This study also includes Computational Fluid Dynamics (CFD) calculations to evaluate the impact of optimized AuNRs on heat generation in a real-world scenario. A case study is presented in which lasers of different wavelengths irradiate a borosilicate glass embedded with a slab of AuNRs at its center. The results, reported as temperature distributions and temperature evolution during irradiation, indicate that the optimized AuNRs significantly enhance heat generation across various laser wavelengths. Specifically, temperature increases were observed as follows: from 2.28 to [Formula: see text] at 465 nm, from 1.91 to [Formula: see text] at 532 nm, from 1.7 to [Formula: see text] at 640 nm, from 40 to [Formula: see text] at 808 nm, and from 0.94 to [Formula: see text] at 980 nm, respectively. These findings underscore the effectiveness of the optimization process in enhancing photothermal conversion.

Recent advances in fundamental research on photon avalanches on the nanometre scale

In recent years, Photon Avalanche (PA) on the nanometre scale has emerged as a groundbreaking phenomenon, enabling the generation of high-energy photons with minimal pumping power due to its highly nonlinear optical dynamics. This review focuses on the advancement in photon-avalanching nanoparticles (ANPs), composed of lanthanide ion-doped inorganic matrices, which exhibit remarkable optical nonlinear response under low-power excitation. The objective of this article is to provide a comprehensive overview of the PA mechanism in nanoscale materials, with a specific focus on single-ANP systems. Key factors influencing the PA characteristics, such as excitation-power threshold, excited-state absorption, cross-relaxation process, dopant ion concentration, and temperature sensitivity are summarized. Furthermore, the review situates recent ANP research within the broader context of early studies on the PA mechanism observed in bulk crystals and optical fibers, highlighting the distinctive features and applications of ANPs. Notable applications discussed include single-particle and biological super-resolution imaging, deep-tissue imaging, luminescence thermometry, ANP-based lasers, optical data storage, and information security. The paper also addresses current challenges and limitations of ANPs in practical applications, proposing potential solutions and future research directions to facilitate their integration into real-world environments. This review aims to serve as a valuable resource for researchers seeking to advance the understanding and application of ANPs in various scientific and technological domains.

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.

Photothermal-Photocatalytic Ternary Heterostructure for Solar Light-Driven Highly Efficient Degradation of Antimicrobial Agents and Inactivation of Superbugs

A significant proportion of antimicrobial agents, such as different antibiotics discharged into the environment via human and animal waste, poses significant problems for ecological balance and human health. Moreover, widespread overuse and misuse of antibiotics have led to antibiotic-resistant bacteria (superbugs), which is one of the biggest global health problems in the 21st century. Since the utilization of solar energy, which is an abundant and natural resource for the photocatalytic system, we report the design of a photothermal-photocatalytic dual-functional light absorber-based ternary heterostructure using plasmonic gold nanoparticle (AuNP)-anchored WO3 nanoplatelet (WO3 NPL)-decorated reduced graphene oxide (r-GO) (AuNP/WO3 NPL/r-GO), which exhibits strong absorption between 400 and 900 nm regions and has the capability for the sunlight-driven 100% degradation of doxycycline antibiotics. Herein, we show that due to the excellent photothermal performance of AuNP and r-GO in the heterostructure, the local temperature increased under 785 NIR nm light irradiation, which boosted the photocatalytic degradation reaction kinetics for doxycycline antibiotics via enhancing the transfer of "hot carriers" and the formation of reactive oxygen species (ROS). Furthermore, experimental data indicate that by integrating photothermal-photocatalytic materials, sunlight can be used for 100% doxycycline antibiotic degradation after 80 min of light irradiation. Moreover, we demonstrate that the ternary heterostructure can be used for sunlight-based 100% inactivation of carbapenem-resistant Enterobacteriaceae Escherichia coli (CRE E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) superbugs by just exposing them to light for 60 min. This study sheds light on the construction of photothermally assisted photocatalytic ternary heterostructures for high-efficiency sunlight-driven degradation of antibiotics and superbugs.

Human 3D Lung Cancer Tissue Photothermal Therapy Using Zn- and Co-Doped Magnetite Nanoparticles

Iron oxide-based nanoparticles are promising materials for cancer thermal therapy and immunotherapy. However, several proofs of concept reported data with murine tumor models that might have limitations for clinical translation. Magnetite is nowadays the most popular nanomaterial, but doping with distinct ions can enhance thermal therapy, namely, magnetic nanoparticle hyperthermia (MNH) and photothermal therapy (PTT). In this study, we used a 3D alveolar reconstructed A549 lung cancer tissue model and investigated the thermal properties, toxicity, and impact of the thermal dose on tissue viability and inflammatory response using magnetite codoped with 40% Zn and 2% Co divalent ions. The ZnCo-doped magnetite nanoparticles are not toxic up to an NP concentration of 30 mg/mL. PTT showed a better heat generation response than MNH under the evaluated conditions, while NP showed a high external photothermal conversion efficiency of ∼1.3 g·L-1·cm-1 at 808 nm. PTT study is carried out at different temperatures, 43 and 47 °C, for 15 min. Tissue viability decreased with increasing thermal dose, while intracelullar ROS levels increased, mitochondrial activity decreased, and active caspase-3 increased, suggesting cell death via apoptosis. Nanoparticles and PTT did not influence the cytokine TNF, IL-10, IL-1B, and IL-12p70. In contrast, IL-6 and IL-8 were triggered by NP and PTT. Increased expression of IL-6 and IL-8 with higher thermal doses is correlated with tissue injury results, suggesting the potential role in activating and attracting immune cells to the site of thermal-mediated tissue injury.

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.

A molybdenum sulfide based nitric oxide controlled release oral gel for rapid healing of oral mucosal ulcers

Oral mucosal ulcer is the most prevalent oral mucosal lesion, affecting over 25 % of general population. The current treatment regimens lack efficacy in addressing challenges such as wound bleeding, bacterial infection and inflammation on a continuous basis. Hence, a multi-functional oral gel (termed MPCST) with a long-acting duration is designed. It is based on a tannic acid-thioctic acid (TATA) supramolecular hydrogel which absorbs tissue exudate while exhibiting robust tissue adhesion properties. To form MPCST, TATA is loaded with MPCS, which are composed of polydopamine (PDA)-coated molybdenum disulfide (MoS2) nanoflakes (MoS2@PDA) with high photothermal conversion efficiency, nitric oxide (NO) precursor nitroprusside (SNP) and cerium oxide (CeO2) with high reactive oxygen species (ROS) scavenging rate. Upon exposure to 808 nm near-infrared (NIR) irradiation, MPCS rapidly heats up and releases NO to promote angiogenesis, while exhibiting strong ROS scavenging, antibacterial (including oral common Streptococcus mutans), and anti-inflammatory properties. Animal experiments show that the MPCST oral gel, composed of MPCS and TATA hydrogel, exhibits superior therapeutic efficacy compared to the commonly used dexamethasone patch.

Reprogramming the Tumor Immune Microenvironment Through Activatable Photothermal Therapy and GSH depletion Using Liposomal Gold Nanocages to Potentiate Anti-Metastatic Immunotherapy

Cancer immunotherapy offers significant clinical benefits for patients with advanced or metastatic tumors. However, immunotherapeutic efficacy is often hindered by the tumor microenvironment's high redox levels, leading to variable patient outcomes. Herein, a therapeutic liposomal gold nanocage (MGL) is innovatively developed based on photo-triggered hyperthermia and a releasable strategy by combining a glutathione (GSH) depletion to remodel the tumor immune microenvironment, fostering a more robust anti-tumor immune response. MGL comprises a thermosensitive liposome shell and a gold nanocage core loaded with maleimide. The flexible shell promotes efficient uptake by cancer cells, enabling targeted destruction through photothermal therapy while triggering immunogenic cell death and the maturation of antigen-presenting cells. The photoactivated release of maleimide depletes intracellular GSH, increasing tumor cell sensitivity to oxidative stress and thermal damage. Conversely, GSH reduction also diminishes immunosuppressive cell activity, enhances antigen presentation, and activates T cells. Moreover, photothermal immunotherapy decreases elevated levels of heat shock proteins in tumor cells, further increasing their sensitivity to hyperthermia. In summary, MGL elicited a robust systemic antitumor immune response through GSH depletion, facilitating an effective photothermal immunotherapeutic strategy that reprograms the tumor microenvironment and significantly inhibits primary and metastatic tumors. This approach demonstrates considerable translational potential and clinical applicability.

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.

In-Situ Grown Nanocrystal TiO2 on 2D Ti3C2 Nanosheets with Anti-Tumor Activity from Photo-Sonodynamic Treatment and Immunology

Introduction

Traditional cancer treatment strategies often have severe toxic side effects and poor therapeutic efficacy. To address the long-standing problems related to overcoming the complexity of tumors, we develop a novel nanozyme based on the in situ oxidation of 2D Ti3C2 structure to perform simultaneous phototherapy and sonodynamic therapy on tumors. Ti3C2 nanozymes exhibit multi-enzyme activity, including intrinsic peroxidase (POD) activities, which can react with H2O2 in the tumor microenvironment. This new material can construct Ti3C2/TiO2 heterostructures in vivo.

Methods

Photothermal (PTT), sonodynamic (SDT) effects, and photoacoustic (PA) image-guided synergy therapy can be achieved. Finally, anticancer immune responses occur with this nanozyme. In vivo experiments revealed that the Ti3C2/TiO2 heterostructure inhibited tumor growth.

Results

Complementarily, our results showed that the Ti3C2/TiO2 heterostructure enhanced the immunogenic activity of tumors by recruiting cytotoxic T cells, thereby enhancing the tumor ablation effect. Mechanistic studies consistently indicated that Reactive Oxygen Species (ROS) regulates apoptosis of HCC cells by modulating NRF2/OSGIN1 signaling both in vitro and in vivo. As a result, Ti3C2 nanozyme effectively inhibited tumor through its synergistic ability to modulate ROS and enhance immune infiltration of cytotoxic T cells in the tumor microenvironment.

Discussion

These findings open up new avenues for enhancing 2D Ti3C2 nanosheets and suggest a new way to develop more effective sonosensitizers for the treatment of cancer.

Neutral Cyanine: Ultra-Stable NIR-II Merocyanines for Highly Efficient Bioimaging and Tumor-Targeted Phototheranostics

Fluorescence imaging (FLI)-guided phototheranostics using emission from the second near-infrared (NIR-II) window show significant potential for cancer diagnosis and treatment. Clinical imaging-used polymethine ionic indocyanine green (ICG) dye is widely adopted for NIR fluorescence imaging-guided photothermal therapy (PTT) research due to its exceptional photophysical properties. However, ICG has limitations such as poor photostability, low photothermal conversion efficiency (PCE), short-wavelength emission peak, and liver-targeting issues, which restrict its wider use. In this study, two ionic ICG derivatives are transformed into neutral merocyanines (mCy) to achieve much-enhanced performance for NIR-II cancer phototheranostics. Initial designs of two ionic dyes show similar drawbacks as ICG in terms of poor photostability and low photothermal performance. One of the modified neutral molecules, mCy890, shows significantly improved stability, an emission peak over 1000 nm, and a high photothermal PCE of 51%, all considerably outperform ICG. In vivo studies demonstrate that nanoparticles of the mCy890 can effectively accumulate at the tumor sites for cancer photothermal therapy guided by NIR-II fluorescence imaging. This research provides valuable insights into the development of neutral merocyanines for enhanced cancer phototheranostics.

Iron Oxide Nanoparticles: Parameters for Optimized Photoconversion Efficiency in Synergistic Cancer Treatment

Photothermal therapy (PTT) can overcome cancer treatment resistance by enhancing the cell membrane permeability, facilitating drug accumulation, and promoting drug release within the tumor tissue. Iron oxide nanoparticles (IONPs) have emerged as effective agents for PTT due to their unique properties and biocompatibility. Approved for the treatment of anemia, as MRI contrast agents, and as magnetic hyperthermia mediators, IONPs also offer excellent light-to-heat conversion and can be manipulated using external magnetic fields for targeted accumulation in specific tissue. Optimizing parameters such as the laser wavelength, power density, shape, size, iron oxidation state, functionalization, and concentration is crucial for IONPs' effectiveness. In addition to PTT, IONPs enhance other cancer treatment modalities. They improve tumor oxygenation, enhancing the efficacy of radiotherapy and photodynamic therapy. IONPs can also trigger ferroptosis, a programmed cell death pathway mediated by iron-dependent lipid peroxidation. Their magneto-mechanical effect allows them to exert a mechanical force on cancer cells to destroy tumors, minimizing the damage to healthy tissue. This review outlines strategies for the management of the photothermal performance and PTT efficiency with iron oxide nanoparticles, as well as synergies with other cancer therapies.

Multifunctional Inorganic-Organic Composite Carriers for Synergistic Dual Therapy of Melanoma

Many methods for cancer treatment have been developed. Among them photothermal therapy (PTT) has drawn the most significant attention due to its noninvasiveness, remote control activation, and low side effects. However, a limited depth of light penetration of PTT is the main drawback. To improve the therapeutic efficiency, the development of combined PTT with other therapeutic agents is highly desirable. In this work, we have designed multifunctional composite carriers based on polylactic acid (PLA) particles decorated with gold nanorods (Au NRs) as nanoheaters and selenium nanoparticles (Se NPs) for reactive oxygen species (ROS) production in order to perform a combined PTT against B16-F10 melanoma. To do this, we have optimized the synthesis of PLA particles modified with Se NPs and Au NRs (PLA-Se:Au), studied the cellular interactions of PLA particles with B16-F10 cells, and analyzed in vivo biodistribution and tumor inhibition efficiency. The results of in vitro and in vivo experiments demonstrated the synergistic effect from ROS induced by Se NPs and the heating from Au NRs. In melanoma tumor-bearing mice, intratumoral injection of PLA-Se:Au followed by laser irradiation leads to almost complete elimination of tumor tissues. Thus, the optimal photothermal properties and ROS-generating capacity allow us to recommend PLA-Se:Au as a promising candidate for the development of the combined PTT against melanoma.

Controllable Gold Nanocluster-Emulsion Interface for Direct Cell Penetration and Photothermal Killing

In the view of their ability to be uptaken by cells, colloidal particles can exert diverse physiological effects and are promising vehicles for the intracellular delivery of biologically active substances. Given that the modulation of biomaterial interfaces greatly facilitates the prediction and control of the corresponding cellular responses, the interfacial behavior of hydrophobic dye-modified gold (Au) nanoclusters (Au NCs) is rationally designed to develop Au NC-containing emulsions and control their biointerfacial interactions with cell membranes. The observed biological performance is indicative of a physical penetration mechanism. The amphiphilic Au NCs decrease the interfacial energy of two immiscible liquids and hinder droplet coalescence to facilitate the formation of emulsions thermodynamically stabilized by dipole-dipole and hydrophobic interactions. Moreover, the amphiphilic Au NCs are localized on the emulsion droplet surface and form segregated interfacial microdomains that adapt to the membrane structure and facilitate the traverse of the emulsions across the cell membrane via direct penetration. Fast penetration coupled with excellent photophysical performance endows the emulsions with multifluorescence tracing and efficient photothermal killing capabilities. The successful change of the interaction mode between NCs and biological objects and the provision of a universal formulation to modulate biointerfacial interactions are expected to inspire new bioapplications.

NIR Light-Activated and RGD-Conjugated Ultrasmall Fe/PPy Nanopolymers for Enhanced Tumor Photothermal Ferrotherapy and MR Imaging

Iron-based nanomaterials have shown great promise for tumor ferrotherapy in recent years. However, nanoparticle-induced ferroptosis has low therapeutic efficacy owing to unsatisfactory Fenton reaction activity in a typical tumor microenvironment. In this study, NIR light-activated Fe/PPy-RGD nanopolymers were developed to combine photothermal therapy and ferrotherapy and achieve enhanced antitumor activity. Importantly, Fe/PPy-RGD exhibited excellent therapeutic performance under NIR light activation both in vitro and in vivo. Under irradiation with NIR light, the heat generated by Fe/PPy-RGD not only induced a therapeutic photothermal effect but also enhanced the release of iron ions and the Fenton reaction by inducing ferroptosis. Additionally, by virtue of RGD conjugation and its ultrasmall size, Fe/PPy-RGD could effectively accumulate at tumor sites in living mice after systemic administration and could be monitored via MR imaging. Hence, this study provides a promising approach for integrating ferrotherapy with photothermal therapy to achieve enhanced tumor treatment.

Photothermal Conversion Efficiency of Silver and Gold Incorporated Nanosized Apatites for Biomedical Applications

The aim of this research was to investigate the photothermal ability of nanocrystalline hydroxyapatite (nHAp) incorporated with silver and gold. It was studied by using a recently developed technique evaluating the photothermal conversion efficiency. The heating performance of aqueous dispersions was examined under 445 and 532 nm excitation. The largest increase in temperature was found for the 2% Ag-nHAp and reached above 2 °C per mg/mL of sample (445 nm) under 90 mW laser continuous irradiation and an external light-to-heat conversion efficiency of 0.11 L/g cm. The obtained results have shown a new functionality of nanosized apatites that has not been considered before. The studied materials have also been characterized by XRPD, TEM, BET, and UV-Vis techniques. Finally, in this work, a new idea for their application was proposed: photothermal therapy.

Quantitative, precise and multi-wavelength evaluation of the light-to-heat conversion efficiency for nanoparticular photothermal agents with calibrated photoacoustic spectroscopy

Biomedical photothermal therapy with optical nanoparticles is based on the conversion of optical energy into heat through three steps: optical absorption, thermal conversion of the absorbed energy and heat transfer to the surrounding medium. The light-to-heat conversion efficiency (LHCE) has become one of the main metrics to quantitatively characterize the last two steps and evaluate the merit of nanoparticules for photothermal therapy. The estimation of the LHCE is mostly performed by monitoring the temperature evolution of a solution under laser irradiation. However, this estimation strongly depends on the experimental set-up and the heat balance model used. We demonstrate here, theoretically and experimentally, that the LHCE at multiple wavelengths can be efficiently and directly determined, without the use of models, by calibrated photoacoustic spectroscopy. The method was validated using already characterized colloidal suspensions of silver sulfide nanoparticles and maghemite nanoflowers and an uncertainty of 3 to 7% was estimated for the LHCE determination. Photoacoustic spectroscopy provides a new, precise and robust method of analysis of the photothermal capabilities of aqueous solutions of nanoagents.

Confining Prepared Ultrasmall Nanozymes Loading ATO for Lung Cancer Catalytic Therapy/Immunotherapy

Nanozymes with inherent enzyme-mimicking catalytic properties combat malignant tumor progression via catalytic therapy, while the therapeutic efficacy still needs to be improved. In this work, ultrasmall platinum nanozymes (nPt) in a confined domain of a wormlike pore channel in gold nanobipyramidal-mesoporous silica dioxide nanocomposites, producing nanozyme carriers AP-mSi with photoenhanced peroxidase ability, are innovatively synthesized. Afterward, based on the prepared AP-mSi, a lung-cancer nanozymes probe (AP-HAI) is ingeniously produced by removing the SiO2 template, modifying human serum albumin, and loading atovaquone molecules (ATO) as well as IR780. Under NIR light irradiation, inner AuP and IR780 collaborate for photothermal process, thus facilitating the peroxidase-like catalytic process of H2 O2 . Additionally, loaded ATO, a cell respiration inhibitor, can impair tumor respiration metabolism and cause oxygen retention, hence enhancing IR780's photodynamic therapy (PDT) effectiveness. As a result, IR780's PDT and nPt nanozymes' photoenhanced peroxidase-like ability endow probes a high ROS productivity, eliciting antitumor immune responses to destroy tumor tissue. Systematic studies reveal that the obvious reactive oxygen species (ROS) generation is obtained by the strategy of using nPt nanozymes and reducing oxygen consumption by ATO, which in turn enables lung-cancer synergetic catalytic therapy/immunogenic-cell-death-based immunotherapy. The results of this work would provide theoretical justification for the practical use of photoenhanced nanozyme probes.

The energetic and physical concept of gold nanorod-dependent fluorescence in cancer treatment and development of new photonic compounds|review

The optical features of gold nanorods (GNR) may be precisely controlled by manipulating their size, shape, and aspect ratio. This review explores the impact of these parameters on the optical tuning of (GNR). By altering the experimental conditions, like the addition of silver ions during the seed-mediated growth process, the aspect ratio of (GNR) may be regulated. The shape is trans from spherical to rod-like structures resulting in noticeable changes in the nanoparticles surface plasmons resonance (SPR) bands. The longitudinal SPR band, associated with electron oscillations along the long axis, exhibits a pronounced red shift into the (NIR) region as the aspect ratio increases. In contrast, the transverse SPR band remains relate unchanged. Using computational methods like the discrete dipole approximation (DDA) allows for analyzing absorption, scattering, and total extinction features of gold (G) nanoparticles. Studies have shown that increasing the aspect ratio enhances the scattering efficiency, indicating a higher scattering quantum yield (QY). These findings highlight the importance of size, shape, and aspect ratio in controlling the optical features of (GNR) providing valuable insights for various uses in nanophotonics and plasmonic-dependent fluorescence in cancer treatment and developing new photonic compound NRs.

Emergence of magnetic nanoparticles in photothermal and ferroptotic therapies

With their distinctive physicochemical features, nanoparticles have gained recognition as effective multifunctional tools for biomedical applications, with designs and compositions tailored for specific uses. Notably, magnetic nanoparticles stand out as first-in-class examples of multiple modalities provided by the iron-based composition. They have long been exploited as contrast agents for magnetic resonance imaging (MRI) or as anti-cancer agents generating therapeutic hyperthermia through high-frequency magnetic field application, known as magnetic hyperthermia (MHT). This review focuses on two more recent applications in oncology using iron-based nanomaterials: photothermal therapy (PTT) and ferroptosis. In PTT, the iron oxide core responds to a near-infrared (NIR) excitation and generates heat in its surrounding area, rivaling the efficiency of plasmonic gold-standard nanoparticles. This opens up the possibility of a dual MHT + PTT approach using a single nanomaterial. Moreover, the iron composition of magnetic nanoparticles can be harnessed as a chemotherapeutic asset. Degradation in the intracellular environment triggers the release of iron ions, which can stimulate the production of reactive oxygen species (ROS) and induce cancer cell death through ferroptosis. Consequently, this review emphasizes these emerging physical and chemical approaches for anti-cancer therapy facilitated by magnetic nanoparticles, combining all-in-one functionalities.

AS1411-conjugated doxorubicin-loaded silver nanotriangles for targeted chemo-photothermal therapy of breast cancer

Background: Combination therapy has attracted tremendous interest for its great potential in treating cancers. Materials & methods: Based on chitosan-coated silver nanotriangles, polyethylene glycol, AS1411 aptamer and doxorubicin, a multifunctional nanocomposite (AS1411-DOX-AgNTs) was constructed and characterized. Then the photothermal properties, ability to target breast cancer cells and anti-breast cancer effect of AS1411-DOX-AgNTs were evaluated. Results: AS1411-DOX-AgNTs were successfully fabricated and showed excellent photothermal conversion efficiency, breast cancer cell and tumor targeting ability. Compared with single treatments, the combination of AS1411-DOX-AgNTs with near-infrared irradiation possessed the strongest anti-breast cancer effect in vitro and in vivo. Conclusion: AS1411-DOX-AgNTs hold great potential in targeted DOX delivery and combined chemo-photothermal therapy for breast cancer.

A local water molecular-heating strategy for near-infrared long-lifetime imaging-guided photothermal therapy of glioblastoma

Owing to the strong absorption of water in the near-infrared (NIR) region near 1.0 μm, this wavelength is considered unsuitable as an imaging and analytical signal in biological environments. However, 1.0 μm NIR can be converted into heat and used as a local water-molecular heating strategy for the photothermal therapy of biological tissues. Herein, we describe a Nd-Yb co-doped nanomaterial (water-heating nanoparticles (NPs)) as strong 1.0 μm emissive NPs to target the absorption band of water. Furthermore, introducing Tm ions into the water-heating NPs improve the NIR lifetime, enabling the development of a NIR imaging-guided water-heating probe (water-heating NIR NPs). In the glioblastoma multiforme male mouse model, tumor-targeted water-heating NIR NPs reduce the tumor volume by 78.9% in the presence of high-resolution intracranial NIR long-lifetime imaging. Hence, water-heating NIR NPs can be used as a promising nanomaterial for imaging and photothermal ablation in deep-tissue-bearing tumor therapy.

Nanomaterials for photothermal cancer therapy

Cancer has emerged as a pressing global public health issue, and improving the effectiveness of cancer treatment remains one of the foremost challenges of modern medicine. The primary clinical methods of treating cancer, including surgery, chemotherapy and radiotherapy, inevitably result in some adverse effects on the body. However, the advent of photothermal therapy offers an alternative route for cancer treatment. Photothermal therapy relies on photothermal agents with photothermal conversion capability to eliminate tumors at high temperatures, which offers advantages of high precision and low toxicity. As nanomaterials increasingly play a pivotal role in tumor prevention and treatment, nanomaterial-based photothermal therapy has gained significant attention owing to its superior photothermal properties and tumor-killing abilities. In this review, we briefly summarize and introduce the applications of common organic photothermal conversion materials (e.g., cyanine-based nanomaterials, porphyrin-based nanomaterials, polymer-based nanomaterials, etc.) and inorganic photothermal conversion materials (e.g., noble metal nanomaterials, carbon-based nanomaterials, etc.) in tumor photothermal therapy in recent years. Finally, the problems of photothermal nanomaterials in antitumour therapy applications are discussed. It is believed that nanomaterial-based photothermal therapy will have good application prospects in tumor treatment in the future.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

Peptide-mediated Aqueous Synthesis of NIR-II Emitting Ag2 S Quantum Dots for Rapid Photocatalytic Bacteria Disinfection

Pathogenic microorganisms in the environment are a great threat to global human health. The development of disinfection method with rapid and effective antibacterial properties is urgently needed. In this study, a biomimetic silver binding peptide AgBP2 was introduced to develop a facile synthesis of biocompatible Ag₂ S quantum dots (QDs). The AgBP2 capped Ag₂ S QDs exhibited excellent fluorescent emission in the second near-infrared (NIR-II) window, with physical stability and photostability in the aqueous phase. Under 808 nm NIR laser irradiation, AgBP2-Ag₂ S QDs can serve not only as a photothermal agent to realize NIR photothermal conversion but also as a photocatalyst to generate reactive oxygen species (ROS). The obtained AgBP2-Ag₂ S QDs achieved a highly effective disinfection efficacy of 99.06 % against Escherichia coli within 25 min of NIR irradiation, which was ascribed to the synergistic effects of photogenerated ROS during photocatalysis and hyperthermia. Our work demonstrated a promising strategy for efficient bacterial disinfection.

Optical switching a photon-avalanche-like mechanism in NdAl3(BO3)4 particles excited at 1064 nm by an auxiliary beam at 808 nm

In recent years, an unconventional excitation of trivalent neodymium ions (N d ³⁺) at 1064 nm, not resonant with ground-state transitions, has been investigated with the unprecedented demonstration of a photon-avalanche-like (PA-like) mechanism, in which the temperature increase plays a fundamental role. As a proof-of-concept, N d A l ₃(B O ₃)₄ particles were used. A consequence of the PA-like mechanism is the absorption enhancement of excitation photons providing light emission at a broad range covering the visible and near-infrared spectra. In the first study, the temperature increase was due to intrinsic nonradiative relaxations from the N d ³⁺ and the PA-like mechanism ensued at a given excitation power threshold (P _{t h} ). Subsequently, an external heating source was used to trigger the PA-like mechanism while keeping the excitation power below P _{t h} at room temperature. Here, we demonstrate the switching on of the PA-like mechanism by an auxiliary beam at 808 nm, which is in resonance with the N d ³⁺ ground-state transition ⁴ I _9/2→{⁴ F _5/2,² H _9/2}. It comprises the first, to the best of our knowledge, demonstration of an optical switched PA, and the underlying physical mechanism is the additional heating of the particles due to the phonon emissions from the N d ³⁺ relaxation pathways when exciting at 808 nm. The present results have potential applications in controlled heating and remote temperature sensing.