Organic molecule-based photothermal agents: an expanding photothermal therapy universe

J-aggregates of strong electron-donating groups linked Aza-BODIPY adjusting by polypeptide for NIR-II phototheranostics

The commonly employed strategies for engineering second near-infrared (NIR-II) organic phototheranostic agents are based on expanding conjugated backbone length, strengthening donor (D)-acceptor (A) effect, or forming J-aggregates. We constructed the D-A-D' structure by incorporating strong electron-donating methoxy and tetraphenylethene (TPE) moieties on the electron-deficient Aza-BODIPY core, and simultaneously expanded the π-conjugation effect by introducing thiophene groups, to obtain a dye BDP-TPE. Next, the nanoparticles P-TPE were prepared via the assembly of BDP-TPE with amphiphilic polypeptides (mPEG2000-P(Asp)10), and successfully constructed the J-aggregates. The obtained P-TPE exhibited strong absorption and fluorescence with maxima at 808 and 1018 nm, respectively, with a conspicuous absolute quantum yield of 0.241 %. Moreover, P-TPE also showed excellent biocompatibility, and high photothermal conversion efficiency of 61.15 %, and excellent resistance to pH, long-term storage, and photobleaching. In vitro and in vivo experiments revealed that P-TPE exhibited good biocompatibility and effectively achieved NIR-II fluorescence imaging-guided PTT with complete tumor ablation under 808 nm laser irradiation. These results provided good evidence for the use of P-TPE as a NIR-II fluorescence imaging-guided PTT therapeutic agent in vivo.

Multifunctional long afterglow nanoparticles with enhanced photothermal effects for in vivo imaging and tumor-targeting therapy

Considering the excellent properties such as deep tissue penetration, high signal-to-noise ratio, and in-situ recharge and reactivation, near-infrared luminescence long afterglow nanoparticles show considerable promise for biological application, especially in multifunctional imaging, targeting, and synergistic therapeutic. In this paper, Zn3Ga4GeO11: 0.1 % Cr3+, 1 % Yb3+, 0.1 % Tm3+@Ag-FA (ZGGO@Ag-FA, ZGA-FA) nanoparticles were synthesized by in-situ growth of Ag nanoparticles on the surface of long afterglow nanoparticles, and further modified with folic acid. Through precise adjustments, the luminescent properties of ZnGa2O4 were enhanced and notably boosted the photothermal effect of Ag by leveraging the upconversion emission of ZGGO, with a photothermal conversion efficiency reaching about 59.9 %. The ZGA-FA nanoparticles are ultra-small, measuring less than 50 nm. The modification with folic acid provides the ZGA-FA nanoparticles with excellent tumor-targeting capabilities, demonstrating effective enrichment and retention in tumor tissues, thus enabling long-term imaging and therapy through in vivo re-excitation. Due to its stable photothermal effect, outstanding near-infrared (NIR) afterglow imaging, and red-light charged characteristics, combined with effective tumor-targeting abilities, the therapeutic strategy proposed by this study has significant potential for clinical applications.

GSH-responsive bithiophene Aza-BODIPY@HMON nanoplatform for achieving triple-synergistic photoimmunotherapy

Photoimmunotherapy represents an innovative approach to enhancing the efficiency of immunotherapy in cancer treatment. This approach involves the fusion of immunotherapy and phototherapy (encompassing techniques like photodynamic therapy (PDT) and photothermal therapy (PTT)). Boron-dipyrromethene (BODIPY) has the potential to trigger immunotherapy owing to its excellent PD and PT efficiency. However, the improvements in water solubility, bioavailability, PD/PT combined efficiency, and tumor tissue targeting of BODIPY require introduction of suitable carriers for potential practical application. Herein, a disulfide bond-based hollow mesoporous organosilica (HMON) with excellent biocompatibility and GSH-responsive degradation properties was used as a carrier to load a bithiophene Aza-BODIPY dye (B5), constructing a sample chemotherapy reagent-free B5@HMON nanoplatform achieving triple-synergistic photoimmunotherapy. HMON, involving disulfide bond, is utilized to improve water solubility, tumor tissue targeting, and PD efficiency by depleting GSH and enhancing host-guest interaction between B5 and HMO. The study reveals that HMON's large specific surface area and porous properties significantly enhance the light collection and oxygen adsorption capacity. The HMON's rich mesoporous structure and internal cavity achieved a loading rate of B5 at 11 %. It was found that the triple-synergistic nanoplatform triggered a stronger anti-tumor immune response, including tumor invasion, cytokine production, calreticulin translocation, and dendritic cell maturation, eliciting specific tumor-specific immunological responses in vivo and in vitro. The BALB/c mouse model with 4T1 tumors was used to assess tumor suppression efficiency in vivo, showing that almost all tumors in the B5@HMON group disappeared after 14 days. Such a simple chemotherapy reagent-free B5@HMON nanoplatform achieved triple-synergistic photoimmunotherapy.

J-aggregates of multi-groups cyanine dye for NIR-IIa fluorescence-guided mild photothermal therapy under 1064 nm irradiation

NIR-IIa fluorescence imaging (FI) and NIR-II photothermal therapy (PTT) have gained popularity due to the advantages of high temporal and spatial resolution and deep penetration. However, the hyperthermia (>48 °C) of conventional PTT with nonspecific warming and thermal diffusion may inevitably cause damage to healthy tissues or organs surrounding the tumor. Therefore, it is highly desirable to provide effective cancer treatment by implementing mild photothermal therapy (mPTT) at mild temperatures with lower laser power density. Here, the nanotheranostic platform FN@P-GA NPs with NIR-II absorption and NIR-IIa emission was developed by constructing J-aggregates. FN@P-GA possesses good biocompatibility, favorable NIR-IIa FI performance, decent stability, and high photothermal conversion efficiency (57.6 %), which lays a solid foundation for FI-guided mPTT. Due to its ability to effectively down-regulate the expression of HSP90 and reduce cellular thermoresistance to kill cancer cells, FN@P-GA successfully achieved NIR-IIa FI-guided mPTT and demonstrated its potent anti-tumor effect under 1064 nm laser irradiation at mild temperature and low power density (0.3 W/cm2).

Rutin-coated ultrasmall manganese oxide nanoparticles for targeted magnetic resonance imaging and photothermal therapy of malignant tumors

Manganese oxide nanoparticles (MONs)-based contrast agents have attracted increasing attention for magnetic resonance imaging (MRI), attributed to their good biocompatibility and advantageous paramagnetism. However, conventional MONs have poor imaging performance due to low T1 relaxivity. Additionally, their lack of tumor-targeting theranostics capabilities and complex synthesis pathways have impeded clinical applications. Rutin (Ru) is an ideal tumor-targeted ligand that targets glucose transporters (GLUTs) overexpressed in various malignant tumors, and exhibits photothermal effects upon chelation with metal ions. Herein, a series of Ru-coated MONs (Ru/MnO2) were synthesized using a straightforward, rapid one-step process. Specifically, Ru/MnO2-5, with the smallest crystal size of approximately 4 nm, exhibits the highest T1 relaxivity (33.3 mM-1s-1 at 1.5 T, surpassing prior MONs) along with notable stability, photothermal efficacy, and tumor-targeting ability. Furthermore, Ru/MnO2-5 shows promise in MRI and photothermal therapy of H22 tumors owing to its superior GLUTs-mediated tumor-targeting capability.

Cross-linker engineered poly(hydroxyethyl methacrylate) hydrogel allows photodynamic and photothermal therapies and controlled drug release

Here, we disclose the synthesis of poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels incorporating a squaraine dye (Sq) as a chemical crosslinker, viz. Sq@PHEMA. Photothermal and photodynamic features of Sq@PHEMA hydrogels are evaluated in detail. It is noteworthy that Sq@PHEMA induces hyperthermia upon irradiation with an 808 nm laser. Furthermore, Sq@PHEMA enables the generation of reactive oxygen species (ROS) upon irradiation with red light. To our delight, Sq@PHEMA hydrogels can be used as efficient dual photosensitizers pertinent to both PDT and PTT simultaneously. Finally, the hydrogels are loaded with methotrexate (MTX) to investigate controlled drug release behavior. It is noted that Sq@PHEMA hydrogels are promising candidates as drug delivery systems since on-demand MTX release is feasible upon irradiation. In summary, we effectively demonstrate that hydrogel cross-linker engineering allows for synergistic photodynamic and photothermal therapy. Furthermore, drug delivery is also feasible with the Sq@PHEMA core.

Lipo/TK-CDN/TPP/Y6 nanoparticles inhibit cutaneous melanoma formation

Stimulation of the innate immune stimulator of interferon genes (STING) pathway has been shown to boost anti-tumour immunity. Nevertheless, the systemic delivery of STING agonists to the tumour presents challenges. Therefore, we designed a cyclic dinucleotide (CDN)-based drug delivery system (DDS) combined photothermal therapy (PTT)/photodynamic therapy (PDT)/immunotherapy for cutaneous melanoma. We coencapsulated a reactive oxygen species (ROS)-responsive prodrug thioketone-linked CDN (TK-CDN), and photoresponsive agents chlorin E6 (Y6) within mitochondria-targeting reagent triphenylphosphonium (TPP)-modified liposomes (Lipo/TK-CDN/TPP/Y6). Lipo/TK-CDN/TPP/Y6 exhibited a photothermal effect similar to Y6, along with a superior cellular uptake rate. Upon endocytosis by B16F10 cells, Lipo/TK-CDN/TPP/Y6 generated large amounts of ROS under laser irradiation for PDT. Mice bearing B16F10 tumours were intravenously injected with Lipo/TK-CDN/TPP/Y6 and exposed to irradiation, resulting in a substantial inhibition of tumour growth. Exploration of the mechanism of anti-tumour action showed that Lipo/TK-CDN/TPP/Y6 had a stronger stimulation of STING activation and anti-tumour immune cell infiltration compared to other groups. Hence, the Lipo/TK-CDN/TPP/Y6 nanoparticles offer great potential as a DDS for targeted and on-demand drug release at tumour sites. These nanoparticles exhibit promise as a candidate for precise and controllable combination therapy in the treatment of tumours.

Fabrication of conjugated polymers with aggregation-induced near-infrared-II emission for efficient phototheranostics

Conjugated polymers (CPs), which emit in the second near-infrared window (NIR-II, 1000-1700 nm), are used as biomaterials for NIR-II fluorescence imaging because of their adjustable photophysical properties and high optical stability. However, the fluorescence signal of conventional CPs is quenched in an aggregated state due to strong π-π stacking, which results in the closure of the radiation attenuation pathway. To solve this problem, the aggregation-induced emission effect is considered a reasonable strategy for enhancing the aggregative fluorescence of IR-II emitters. We herein report NIR-II conjugated polymers with typical AIE characteristics (αAIE > 3) by changing the side chain structure of receptor units and the conjugation degree of donors. Conjugated polymer nanoparticles (PoBVT NPs) exhibit outstanding performance in NIR-II fluorescence imaging (QY = 1.94%) and highly effective photothermal therapy (η = 45%). In vivo studies have shown that the location of tumors can be accurately obtained by NIR-II FL/NIR-II PA imaging, and there is a significant anti-tumor effect after laser irradiation. This work offers prospects for the design of multifunctional conjugated polymers for NIR-II FL/PA imaging to guide NIR-II PTT applications.

Prostate-Specific Membrane Antigen-Targeted NIR Phototheranostics for Prostate Cancer

The evolution of targeted cancer theranostics has revolutionized personalized medicine by integrating diagnostic and therapeutic capabilities. Prostate-specific membrane antigen (PSMA) has emerged as a key theranostic target in the context of prostate cancer, paving the way for the clinical approval of multiple drugs. However, the persistent challenge of off-target toxicity, which plagues both conventional and advanced treatment modalities such as targeted chemotherapy and radiotherapy, thus demands further innovation. Considering this critical issue, this review discusses the recent advances in the binary treatment techniques, i.e., phototherapies, that have the potential to circumvent the key concern of off-target toxicity associated with personalized chemotherapy and radiotherapy. Precisely, an up-to-date overview of the latest developments in the near-infrared (NIR)-based phototheranostic strategies for prostate cancer by targeting PSMA has been presented. Furthermore, we have discussed the associated particulars that require specific attention in enhancing the translational potential of phototheranostic techniques.

Tumor microenvironment ameliorative and adaptive nanoparticles with photothermal-to-photodynamic switch for cancer phototherapy

The notorious tumor microenvironment (TME) usually becomes more deteriorative during phototherapeutic progress that hampers the antitumor efficacy. To overcome this issue, we herein report the ameliorative and adaptive nanoparticles (TPASIC-PFH@PLGA NPs) that simultaneously reverse hypoxia TME and switch photoactivities from photothermal-dominated state to photodynamic-dominated state to maximize phototherapeutic effect. TPASIC-PFH@PLGA NPs are designed by incorporating oxygen-rich liquid perfluorohexane (PFH) into the intraparticle microenvironment to regulate the intramolecular motions of AIE photosensitizer TPASIC. TPASIC exhibits a unique aggregation-enhanced reactive oxygen species (ROS) generation feature. PFH incorporation affords TPASIC the initially dispersed state, thus promoting active intramolecular motions and photothermal conversion efficiency. While PFH volatilization leads to nanoparticle collapse and the formation of tight TPASIC aggregates with largely enhanced ROS generation efficiency. As a consequence, PFH incorporation not only currently promotes both photothermal and photodynamic efficacies of TPASIC and increases the intratumoral oxygen level, but also enables the smart photothermal-to-photodynamic switch to maximize the phototherapeutic performance. The integration of PFH and AIE photosensitizer eventually delivers more excellent antitumor effect over conventional phototherapeutic agents with fixed photothermal and photodynamic efficacies. This study proposes a new nanoengineering strategy to ameliorate TME and adapt the treatment modality to fit the changed TME for advanced antitumor applications.

Aggregable gold nanoparticles for cancer photothermal therapy

Photothermal therapy (PTT) is an important non-invasive cancer treatment method. Enhancing the photothermal conversion efficiency (PCE) of photothermal agents (PTAs) and prolonging their tumor accumulation and retention are effective strategies to enhance the efficiency of cancer PTT. Recently, tremendous progress has been made in developing stimuli-responsive aggregable gold nanoparticles as effective PTAs for PTT. In this review, we discuss the chemical principles underlying gold nanoparticle aggregation and highlight the progress in gold nanoparticle aggregation triggered by different stimuli, especially tumor microenvironment-related factors, for cancer PTT. Covalent condensation reactions, click cycloaddition reactions, chelation reactions, and Au-S bonding, as well as non-covalent electrostatic interactions, hydrophobic interactions, hydrogen bonding, and van der Waals forces play key roles in the aggregation of gold nanoparticles. Enzymes, pH, reactive oxygen species, small molecules, salts, and light drive the occurrence of gold nanoparticle aggregation. Targeted aggregation of gold nanoparticles prolongs tumor accumulation and retention of PTAs and improves PCE, resulting in enhanced tumor PTT. Moreover, the major challenges of aggregable gold nanoparticles as PTAs are pointed out and the promising applications are also prospected at the end. With the deepening of research, we expect aggregable gold nanoparticles to become essential PTAs for tumor therapy.

Bimetallic Single-Atom Nanozyme-Based Electrochemical-Photothermal Dual-Function Portable Immunoassay with Smartphone Imaging

Rapid and accurate detection of human epidermal growth factor receptor 2 (HER2) is crucial for the early diagnosis and prognosis of breast cancer. In this study, we reported an iron-manganese ion N-doped carbon single-atom catalyst (FeMn-NCetch/SAC) bimetallic peroxidase mimetic enzyme with abundant active sites etched by H2O2 and further demonstrated unique advantages of single-atom bimetallic nanozymes in generating hydroxyl radicals by density functional theory (DFT) calculations. As a proof of concept, a portable device-dependent electrochemical-photothermal bifunctional immunoassay detection platform was designed to achieve reliable detection of HER2. In the enzyme-linked reaction, H2O2 was generated by substrate catalysis via secondary antibody-labeled glucose oxidase (GOx), while FeMn-NCetch/SAC nanozymes catalyzed the decomposition of H2O2 to form OH*, which catalyzed the conversion of 3,3',5,5'-tetramethylbenzidine (TMB) to ox-TMB. The ox-TMB generation was converted from the colorimetric signals to electrical and photothermal signals by applied potential and laser irradiation, which could be employed for the quantitative detection of HER2. With the help of this bifunctional detection technology, HER2 was accurately detected in two ways: photothermally, with a linear scope of 0.01 to 2.0 ng mL-1 and a limit of detection (LOD) of 7.5 pg mL-1, and electrochemically, with a linear scope of 0.01 to 10 ng mL-1 at an LOD of 3.9 pg mL-1. By successfully avoiding environmental impacts, the bifunctional-based immunosensing strategy offers strong support for accurate clinical detection.

BF2-Bridged Azafulvene Dimer-Based 1064 nm Laser-Driven Superior Photothermal Agent for Deep-Seated Tumor Therapy

Small organic photothermal agents (PTAs) with absorption bands located in the second near-infrared (NIR-II, 1000-1700 nm) window are highly desirable for effectively combating deep-seated tumors. However, the rarely reported NIR-II absorbing PTAs still suffer from a low molar extinction coefficient (MEC, ϵ), inadequate chemostability and photostability, as well as the high light power density required during the therapeutic process. Herein, we developed a series of boron difluoride bridged azafulvene dimer acceptor-integrated small organic PTAs. The B-N coordination bonds in the π-conjugated azafulvene dimer backbone endow it the strong electron-withdrawing ability, facilitating the vigorous donor-acceptor-donor (D-A-D) structure PTAs with NIR-II absorption. Notably, the PTA namely OTTBF shows high MEC (7.21×104 M-1 cm-1), ultrahigh chemo- and photo-stability. After encapsulated into water-dispersible nanoparticles, OTTBF NPs can achieve remarkable photothermal conversion effect under 1064 nm irradiation with a light density as low as 0.7 W cm-2, which is the lowest reported NIR-II light power used in PTT process as we know. Furthermore, OTTBF NPs have been successfully applied for in vitro and in vivo deep-seated cancer treatments under 1064 nm laser. This study provides an insight into the future exploration of versatile D-A-D structured NIR-II absorption organic PTAs for biomedical applications.

Harnessing External Irradiation for Precise Activation of Metal-Based Agents in Cancer Therapy

Cancer is a significant global health issue. Platinum-based chemotherapy drugs, including cisplatin, are crucial in clinical anti-cancer treatment. However, these drugs have limitations such as drug resistance, non-specific distribution, and irreversible toxic and side effects. In recent years, the development of metal-based agents has led to the discovery of other anti-cancer effects beyond chemotherapy. Precise spatiotemporal controlled external irradiation can activate metal-based agents at specific sites and play a different role from traditional chemotherapy. These strategies can not only enhance the anti-cancer efficiency, but also show fewer side effects and non-cross-drug resistance, which are ideal approaches to solve the problems caused by traditional platinum-based chemotherapy drugs. In this review, we focus on various metal-based agent-mediated cancer therapies that are activated by three types of external irradiation: near-infrared (NIR) light, ultrasound (US), and X-ray, and give some prospects. We hope that this review will promote the generation of new kinds of metal-based anti-cancer agents.

Regulating Charge Transfer in Cyanine Dyes: A Universal Methodology for Enhancing Cancer Phototherapeutic Efficacy

ConspectusDue to the advantages of spatiotemporal selectivity and inherent noninvasiveness, cancer phototherapy, which includes both photodynamic therapy (PDT) and photothermal therapy (PTT), has garnered significant attention in recent years as a promising cancer treatment. Despite the commendable progress in this field, persistent challenges remain. In PDT, limitations in dyes manifest as low intersystem crossing (ISC) efficiency and oxygen-dependent photoactivity, resulting in unsatisfactory performance, particularly under hypoxic conditions. Similarly, PTT encounters consistent insufficiencies in the photothermal conversion efficiency (PCE) of dyes. Additionally, the suboptimal phototherapeutic efficacy often exhibits a limited immune response. These factors collectively impose significant constraints on phototherapy in oncological applications, leading to limited tumor inhibition, tumor recurrence, and even metastasis.Unlike strategies that rely on external assistance with complicated systems, manipulating excited-state deactivation pathways in biocompatible dyes offers a universal way to systematically address these challenges. Our group has devoted considerable effort to achieving this goal. In this Account, we present and discuss our journey in optimizing excited-state energy-release pathways through regulating molecular charge transfer based on cyanine dyes, which are renowned for their exceptional photophysical properties and harmonious biocompatibility. The investigation begins with the introduction of amino groups in the meso position of a heptamethine cyanine dye, where the intramolecular charge transfer (ICT) effect causes a significant enlargement of the Stokes shift. Subsequently, ICT induced by introducing functional electron-deficient groups in cyanines is found to decrease the overlap of electron distribution or narrow the energy gaps of molecular frontier orbitals. Such modifications result in a reduction of the energy gaps between singlet and triplet states or an improvement in internal conversion, ultimately promoting phototherapy efficacy in both primary and distant tumors. Furthermore, with the intensification of the charge transfer effect aided by light, photoinduced intramolecular electron transfer occurs in some cyanines, leading to complete charge separation in the excited state. This process enhances the transition to the ground or triplet states, improving tumor phototherapy and inhibiting metastasis by increasing the PCE or the yield of reactive oxygen species, respectively. Shifting focus from intramolecular to intermolecular interactions, we successfully constructed and explored cyanines based on intermolecular charge transfer. These dyes, with excited-state dynamics mimicking natural photosynthesis, generate radicals and facilitate oxygen-independent hypoxic tumor PDT. Finally, we outlined the existing challenges and future directions for optimizing phototherapeutic efficacy by regulating molecular charge transfer. This Account provides molecular-level insights into improving phototherapeutic performance, offering valuable perspectives, and inspiring the development of functional dyes in other application fields.

NIR-Absorbing Tetraphenylethene-Containing bisBODIPY Nanoplatforms Demonstrate Effective Lysosome-Targeting and Combinational Phototherapy

Photosensitizer-based phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), offer safe treatment modalities for tumor ablation with spatiotemporal precision. After photons are absorbed, PDT creates localized chemical damage by generating reactive oxygen species (ROS), while PTT induces localized thermal damage. However, PDT still faces hypoxic tumor challenges, while PTT encounters issues related to heat resistance and potential overheating. The combination of PDT and PTT shows great potential as an effective anticancer strategy. By targeting lysosomes with carefully designed phototherapeutic reagents for combined phototherapy, rapid dysfunction and cell death in cancer cells can be induced, showing promise for cancer treatment. Herein, two α-α-linked bisBODIPYs with tetraphenylethene (TPE) moieties are designed and synthesized. These TPE-substituted bisBODIPYs expand the absorption into NIR range (λmaxabs/λmaxem ∼ 740/810 nm) and confer aggregation-induced emission (AIE) activity (λmaxem ∼ 912 nm). Moreover, these bisBODIPYs self-assemble with surfactant F-127 into nanoparticles (NPs), which efficiently generate ROS (1O2 and •OH) in both solution and cellular environments and demonstrate superior photothermal conversion efficiencies (η ∼ 68.3%) along with exceptional photothermal stability. More importantly, these NPs showed lysosomal targeting and remarkable tumor ablation in cellular and murine models, indicating their potential in precision tumor therapy.

Recent advances of copper-based metal phenolic networks in biomedical applications

Metal-phenolic Networks (MPNs) are a novel class of nanomaterial developed gradually in recent years which are self-assembled by metal ions and polyphenolic ligands. Due to their environmental protection, good adhesion, and biocompatibility with green phenolic ligands, MPNs can be used as a new type of nanomaterial. They show excellent properties such as anti-inflammatory, antioxidant, antibacterial, and anticancer, and have been widely studied in the biomedical field. As one of the most common subclasses of the MPNs family, copper-based MPNs have been widely studied for drug delivery, Photodynamic Therapy (PDT), Chemo dynamic Therapy (CDT), antibacterial and anti-inflammatory, bone tissue regeneration, skin regeneration wound repair, and metal ion imaging. In this paper, the preparation strategies of different types of copper-based MPNs are reviewed. Then, the application status of copper-based MPNs in the biomedical field under different polyphenol ligands is introduced in detail. Finally, the existing problems and challenges of copper-based MPNs are discussed, as well as their future application prospects in the biomedical field.

Croconaine-based NIR-II fluorescence imaging-guided tumor photothermal therapy induces long-term antitumor immune memory

Photothermal therapy (PTT) for cancers guided by optical imaging has recently shown great potential for precise diagnosis and efficient therapy. The second near-infrared window (NIR-II, 1000-1700 nm) fluorescence imaging (FLI) is highly desirable owing to its good spatial and temporal resolution, deep tissue penetration, and negligible tissue toxicity. Organic small molecules are attractive as imaging and treatment agents in biomedical research because of their low toxicity, fast clearance rate, diverse structures, ease of modification, and excellent biocompatibility. Various organic small molecules have been investigated for biomedical applications. However, there are few reports on the use of croconaine dyes (CRs), especially NIR-II emission CRs. To our knowledge, there have been no prior reports of NIR-II emissive small organic photothermal agents (SOPTAs) based on CRs. Herein, we report a croconaine dye (CR-TPE-T)-based nanoparticle (CR NP) with absorption and fluorescence emission in the NIR-I and NIR-II windows, respectively. The CR NPs exhibited intense NIR absorption, outstanding photothermal properties, and good biological compatibility. In vivo studies showed that CR NPs not only achieved real-time, noninvasive NIR-II FLI of tumors, but also induced significant tumor ablation with laser irradiation guided by imaging, without apparent side effects, and promoted the formation of antitumor immune memory in a colorectal cancer model. In addition, the CR NPs displayed efficient inhibition of breast tumor growth, improved longevity of mice and triggered efficient systemic immune responses, which further inhibited tumor metastasis to the lungs. Our study demonstrates the great potential of CRs as therapeutic agents in the NIR-II region for cancer diagnosis.

Supramolecular antibody-drug conjugates for combined antibody therapy and photothermal therapy targeting HER2-positive cancers

Antibody therapy of anti-HER2 monoclonal antibody (mAb) has been an important strategy in treating HER2-positive cancers. However, the efficacy is restricted by many factors, including the level of HER2 expressed by tumor cells and antibody resistance. To overcome these and boost the efficacy, a novel nanoparticle (NP) was constructed in this study for combined antibody therapy of antibody and photothermal therapy (PTT). This novel NP was assembled from 1-pyrenecarboxylic acid (PCA) functionalized anti-HER2 mAb and indocyanine green (ICG), a photothermal transduction agents (PTA), by non-covalent interactions, which was named as Anti-HER2 mAb-pyrene-indocyanine green (H-P-I). Notably, the constructed H-P-I NP not only maintained the affinity and cytotoxicity of anti-HER2 mAb, but also exhibited high photothermal conversion efficiency mediated by ICG. Both in vitro and in vivo assessments confirmed that compared with monotherapy of antibody or ICG, H-P-I demonstrated preferable efficacy in treating HER2-positive cancers. Further biochemistry analysis and pathological analysis ensured the biosafety of H-P-I administration. Taked together, this study proposes a feasible method for constructing tumor-targeted nano PTA based on anti-HER2 mAb through supramolecular self-assembly strategy, achieving synergistic antibody photothermal anticancer treatment, which has the potential to be a promising candidate for combination therapy of HER2-positive cancers.

Temperature-Responsive "Nano-to-Micro" Transformed Polymersomes for Enhanced Ultrasound/Fluorescence Dual Imaging-Guided Tumor Phototherapy

The perfect integration of microbubbles for efficient ultrasound imaging and nanocarriers for intelligent tumor-targeting delivery remains a challenge in precise tumor theranostics. Herein, we exquisitely fabricated laser-activated and targeted polymersomes (abbreviated as FIP-NPs) for simultaneously encapsulating the photosensitizer indocyanine green (ICG) and the phase change agent perfluorohexane (PFH). The formulated FIP-NPs were nanosize and effectively accumulated into tumors as observed by ICG fluorescence imaging. When the temperature rose above 56 °C, the encapsulated PFH transformed from liquid to gas and the FIP-NPs underwent balloon-like enlargement without structure destruction. Impressively, the enlarged FIP-NPs fused with adjacent polymersomes to form even larger microparticles. This temperature-responsive "nano-to-micro" transformation and fusion process was clearly demonstrated, and FIP-NPs showed greatly improved ultrasound signals. More importantly, FIP-NPs achieved dramatic antitumor efficacy through ICG-mediated phototherapy. Taken together, the novel polymersomes achieved excellent ultrasound/fluorescence dual imaging-guided tumor phototherapy, providing an optimistic candidate for the application of tumor theranostics.

A NIR-II absorbing conjugated polymer based on tetra-fused isoindigo with ultrahigh photothermal conversion efficiency for cancer therapy

A conjugated polymer, P4TTD-DPP, based on tetra-fused isoindigo-alt-diketopyrrolopyrrole, has been synthesized as a photothermal therapeutic nanotransducer within the near-infrared-II (NIR-II) window. P4TTD-DPP exhibits a notable mass extinction coefficient of 62.8 L g-1 cm-1 at 1064 nm. Additionally, P4TTD-DPP nanoparticles demonstrate remarkable photothermal conversion efficiency of 91.5% at 1064 nm and exhibit excellent anticancer efficacy under photothermal conditions.

Engineering an Organic Nanoplatform for Augmented Pyroeletroimmunotherapy

Photothermal immunotherapy has shown great promise in the treatment of tumor metastasis. However, the thermal resistance of tumor cells substantially compromises the treatment effect of photothermal immunotherapy. Herein, a high-performance organic pyroelectric nanoplatform, tBu-TPAD-BF2 nanoparticles (NPs), is rationally engineered for the effective pyroelectroimmunotherapy of tumor metastasis. Biocompatible tBu-TPAD-BF2 NPs with excellent pyroelectric and photothermal conversion properties are constructed by assembling organic, low-bandgap pyroelectric molecules with amphiphilic polymers. After internalization by tumor cells, treatment with tBu-TPAD-BF2 NPs causes an apparent temperature elevation upon near-infrared (NIR) laser irradiation, inducing potent immunogenic cell death (ICD). Additionally, the temperature variations under alternating NIR laser irradiation facilitate reactive oxygen species production for pyroelectric therapy, thus promoting ICD activation and lowering thermal resistance. Importantly, in vivo assessments illustrate that tBu-TPAD-BF2 NPs in combination with NIR laser exposure notably inhibit primary and distant tumor proliferation and prominently retarded lung metastasis. RNA profiling reveals that treatment with tBu-TPAD-BF2 NPs markedly suppresses metastasis under NIR laser illumination by downregulating metastasis-related genes and upregulating immune response-associated pathways. Therefore, this study provides a strategy for designing high-performance pyroelectric nanoplatforms to effectively cure tumor metastasis, thereby overcoming the inherent shortcomings of photothermal immunotherapy.

A Cyanine with 83.2% Photothermal Conversion Efficiency and Absorption Wavelengths over 1200 nm for Photothermal Therapy

Developing small-molecule photothermal agents (PTAs) with good near-infrared-II (NIR-II) response for deeper tissue penetration and minimizing damage to healthy tissues has attracted much attention in photothermal therapy (PTT). However, concentrating ultra-long excitation wavelengths and high photothermal conversion efficiencies (PCEs) into a single organic small molecule is still challenging due to the lack of suitable molecular structures. Here, six polymethine cyanine molecules based on the structure of indocyanine green are synthesized by increasing the conjugated structure of the two-terminal indole salts and the number of rigid methine units, and incorporating longer alkyl side chains into the indole salts. Ultimately, IC-1224 is obtained with an absorption wavelength of more than 1200 nm, which has a high PCE up to 83.2% in the NIR-II window and exhibits excellent PTT tumor ablation performance. This provides a high-performance NIR-II-responsive PTA, and offers further possibilities for the application of PTT in biomedical fields.

Near-infrared II theranostic agents for the diagnosis and treatment of Alzheimer's disease

BACKGROUND

Near-infrared II theranostic agents have gained great momentum in the research field of AD owing to the appealing advantages. Recently, an array of activatable NIR-II fluorescence probes has been developed to specifically monitor pathological targets of AD. Furthermore, various NIR-II-mediated nanomaterials with desirable photothermal and photodynamic properties have demonstrated favorable outcomes in the management of AD.

METHODS

We summerized amounts of references and focused on small-molecule probes, nanomaterials, photothermal therapy, and photodynamic therapy based on NIR-II fluorescent imaging for the diagnosis and treatment in AD. In addition, design strategies for NIR-II-triggered theranostics targeting AD are presented, and some prospects are also addressed.

RESULTS

NIR-II theranostic agents including small molecular probes and nanoparticles have received the increasing attention for biomedical applications. Meanwhile, most of the theranostic agents exhibited the promising results in animal studies. To our surprise, the multifunctional nanoplatforms also show a great potential in the diagnosis and treatment of AD.

CONCLUSIONS

Although NIR-II theranostic agents showed the great potential in diagnosis and treatment of AD, there are still many challenges: 1) Faborable NIR-II fluorohpores are still lacking; 2) Biocompatibility, bioseurity and dosage of NIR-II theranostic agents should be further revealed; 3) New equipment and software associated with NIR-II imaging system should be explored.

Photothermal therapy of xenografted tumor by carbon nanoparticles-Fe(II) complex

Due to the unique structure, carbon nanomaterials could convert near-infrared (NIR) light into heat efficiently in tumor ablation using photothermal therapy (PTT). However, none of them has been applied in clinical treatment, because they have not been approved for clinical evaluations and the precise temperature control facility is scarce. In this study, we designed a temperature-responsive controller for PTT and used carbon nanoparticles-Fe(II) complex (CNSI-Fe) as photothermal conversion agent (PTA) for PTT of tumor in vitro and in vivo. CNSI-Fe was an innovative drug under the evaluations in clinical trials. CNSI-Fe showed excellent photothermal conversion ability in water to increase the water temperature by 40 °C within 5 min under irradiation of 808 nm laser at 0.5 W/cm2. The temperature was precisely controlled at 52 °C for both in vitro and in vivo tumor inhibition. CNSI-Fe with NIR irradiation showed higher tumor cell inhibition than CNSI. In tumor bearing mice, CNSI-Fe with NIR irradiation achieved an inhibition rate of 84.7 % and 71.4 % of them were completely cured. Mechanistically, CNSI-Fe under NIR irradiation induced the radical generation, oxidative damage and ferroptosis to kill tumor. In addition, CNSI-Fe showed good biosafety during PTT according to hematological, serum biological and histopathological examinations. These results indicated that the combination of chemotherapy and PTT provided higher antitumor efficiency using CNSI-Fe as PTA.

Isomer engineering for deep understanding of aggregation-induced photothermal enhancement in conjugated systems

Organic photothermal materials based on conjugated structures have significant potential applications in areas such as biomedical diagnosis, therapy, and energy conversion. Improving their photothermal conversion efficiency through molecular design is critical to promote their practical applications. Especially in similar structures, understanding how the position of heteroatoms affects the conversion efficiency is highly desirable. Herein, we prepared two isomeric small D-A molecules with different sulfur atom positions (TBP-MPA and i-TBP-MPA), which display strong and broad absorption in the UV-visible region due to their strong intramolecular charge transfer characteristics. Compared to i-TBP-MPA, TBP-MPA demonstrates aggregation-induced photothermal enhancement (AIPE). Under simulated sunlight (1 kW m-2) irradiation, the stable temperature of TBP-MPA powder reached 60 °C, significantly higher than the 50 °C achieved by i-TBP-MPA. Experimental and theoretical results indicate that the S⋯N non-covalent interactions in TBP-MPA impart a more rigid conjugated framework to the molecule, inducing ordered molecular stacking during aggregation. This ordered stacking provides additional non-radiative transition channels between TBP-MPA molecules, enhancing their photothermal performance in the aggregated state. Under 1 sun irradiation, TBP-MPA achieved a water evaporation rate of 1.0 kg m-2 h-1, surpassing i-TBP-MPA's rate of 0.92 kg m-2 h-1.

Zwitterionic nanoparticles from indocyanine green dimerization for imaging-guided cancer phototherapy

Indocyanine green (ICG), the only near-infrared (NIR) dye approved for clinical use, has received increasing attention as a theranostic agent wherein diagnosis (fluorescence) is combined with therapy (phototherapy), but suffers rapid hepatic clearance, poor photostability, and limited accumulation at tumor sites. Here we report that dimerized ICG can self-assemble to form zwitterionic nanoparticles (ZN-dICG), which generate fluorescence self-quenching but exhibit superior photothermal and photodynamic properties over ICG. The zwitterionic moieties confer ZN-dICG an ultralow critical micelle concentration and high colloidal stability with low non-specific binding in vivo. In addition, ZN-dICG can respond to the over-generated reactive oxygen species (ROSs) and dissociate to restore NIR fluorescence of ICG, amplifying the sensitivity via albumin binding for low-background imaging of tumors. Following systemic administration, ZN-dICG accumulated in tumors of xenograft-bearing mice for imaging primary and metastatic tumors, and induced tumor ablation under laser irradiation. The discovery of ZN-dICG would contribute to the design of translational phototheranostic platform with high biocompatibility. STATEMENT OF SIGNIFICANCE: Indocyanine green (ICG) has been extensively studied as a phototheranostic agent that combines imaging with phototherapies, but it suffers from rapid hepatic clearance, poor photostability, and limited accumulation at tumor sites. Here, we report a strategy to construct ICG dimers (ICG-tk-ICG) by conjugating two ICG molecules via a thioketal bond, which can self-assemble into zwitterionic nanoparticles (ZN-dICG) at ultralow critical micelle concentrations, exhibiting superior photothermal and photodynamic properties over ICG. ZN-dICG responds to the over-generated ROS in tumors and dissociates to restore the NIR fluorescence of ICG, enhancing the sensitivity via albumin binding for low-background imaging of tumors. This study offers a supramolecular strategy that may potentiate the clinical translation of ICG in imaging-guided cancer phototherapy.

A Processible and Ultrahigh-temperature Organic Photothermal Material through Spontaneous and Quantitative [2+2] Cycloaddition-Cycloreversion

Energy conversion, particularly light to heat conversion, has garnered significant attention owing to its prospect in renewable energy exploitation and utilization. Most previous efforts have focused on developing organic photothermal materials for low-temperature applications, whereas the importance of simplifying the preparation methods of photothermal materials and enhancing their maximum photothermal temperature have been less taken. Herein, we prepare an organic near-infrared (NIR) photothermal material namely ATT by a spontaneous [2+2] cycloaddition-cycloreversion reaction. In addition to the solution-based method, ATT could also be readily preapred by ball milling in a high yield of 90 % in just 15 min. ATT powder exhibits a broad absorption extending beyond 2000 nm, excellent processability, and thermal stability. Remarkably, ATT powder can reach an unprecedently temperature as high as 450 °C while maintaining excellent photostability upon photoirradiation. Leveraging its extraordinary photothermal and processable properties, ATT was used in the high-temperature applications, such as photo-ignition, photo-controlled metal processing and high-temperature shape memory, all of which offer spatiotemporal control capabilities. This work provides a new approach to prepare organic photothermal materials with high temperatures, and pave the way for their applications in extreme environments.

Multi-modal triggered-release sonodynamic/chemo/phototherapy synergistic nanocarriers for the treatment of colon cancer

Most colon cancer patients are diagnosed at an advanced stage, with a grim prognosis. In clinical, various combination therapies have been employed to enhance the efficacy of colon cancer treatment. The essence of combined treatment is the judicious selection and combination of various treatment units. Phototherapy (PT), sonodynamic therapy (SDT), and chemotherapy are treatment modalities that rely on the active molecules to treat tumors, and have been demonstrated to synergistically enhance tumor treatment efficacy. However, the differences in the metabolism of active molecules and hypoxic microenvironment of tumors have limited the synergistic effects of the aforementioned methods. To address this significant issue, in this study, we utilized polydopamine (PDA) as the encapsulated material to form a rigid shell that contains the therapeutic molecules IR-780 and methotrexate (MTX) on the surface of perfluorohexane (PFH) microdroplets through self-assembling method to develop an SDT/chemotherapy/PT combined nanoparticles (SCP NPs). Transmission electron microscopy (TEM) revealed that the nanoparticles exhibited a hollow shell structure, with an average size of approximately 100 nm. SCP NPs have excellent stability and biocompatibility in both in vitro and in vivo. The absorption and emission spectrum of the loaded IR-780 did not exhibit any significant shift, and the photothermal temperature rose to 92°C. Their ultrasonic cavitation effect was good and their cell inhibitory effect of MTX was maintained. SCP NPs can achieve multi-modal triggered release through ultrasound, laser irradiation, and pH, ensuring a simultaneous accumulation of therapeutic molecules in the tumor area and effectively alleviating tumor hypoxia. Additionally, both the near-infrared fluorescence (NIF) signal and the ultrasonic cavitation signal of the nanoparticles can be utilized for tracking and monitoring treatment efficacy. Most notably, SCP NPs exhibited outstanding synergistic treatment effects at low intervention levels, resulting in a 67% cure rate of tumors. These results provide an experimental basis for developing the new clinical treatments for colon cancer.

Remote actuation and on-demand activation of biomaterials pre-incorporated with physical cues for bone repair

The high incidence of bone defect-related diseases caused by trauma, infection, and tumor resection has greatly stimulated research in the field of bone regeneration. Generally, bone healing is a long and complicated process wherein manipulating the biological activity of interventional scaffolds to support long-term bone regeneration is significant for treating bone-related diseases. It has been reported that some physical cues can act as growth factor substitutes to promote osteogenesis through continuous activation of endogenous signaling pathways. This review focuses on the latest progress in bone repair by remote actuation and on-demand activation of biomaterials pre-incorporated with physical cues (heat, electricity, and magnetism). As an alternative method to treat bone defects, physical cues show many advantages, including effectiveness, noninvasiveness, and remote manipulation. First, we introduce the impact of different physical cues on bone repair and potential internal regulatory mechanisms. Subsequently, biomaterials that mediate various physical cues in bone repair and their respective characteristics are summarized. Additionally, challenges are discussed, aiming to provide new insights and suggestions for developing intelligent biomaterials to treat bone defects and promote clinical translation.

Nitroreductase-Responsive Fluorescent "Off-On" Photosensitizer for Hypoxic Tumor Imaging and Dual-Modal Therapy

Photothermal therapy synergized with photodynamic therapy for the treatment of tumors has emerged as a promising strategy. However, designing photosensitizers with both high photothermal efficiency and high photodynamic performance remains challenging. In contrast, the strategy of rationalizing the design of photosensitizers using the physiological properties of tumors to improve the photon utilization of photosensitizers during phototherapy is more advantageous than the approach of endowing a single photosensitizer with complex functions. Herein, we propose a molecular design (CyNP) to convert from photothermal therapy to photodynamic synergistic photothermal therapy based on the prevalent properties of hypoxic tumors. In the normoxic region of tumors, the deactivation pathway of CyNP excited state is mainly the conversion of photon energy to thermal energy; in the hypoxic region of tumors, CyNP is reduced to CyNH by nitroreductase, and the deactivation pathway mainly includes radiation leap, energy transfer between CyNP and oxygen, and conversion of photons energy to heat energy. This strategy enables real-time fluorescence detection of hypoxic tumors, and it also provides dual-mode treatment for photothermal and photodynamic therapy of tumors, achieving good therapeutic effects in vivo tumor treatment. Our study achieves more efficient tumor photoablation and provides a reference for the design ideas of smart photosensitizers.

Recent Advancements in Biomaterials for Chimeric Antigen Receptor T Cell Immunotherapy

Cellular immunotherapy is an innovative cancer treatment method that utilizes the patient's own immune system to combat tumor cells effectively. Currently, the mainstream therapeutic approaches include chimeric antigen receptor T cell (CAR-T) therapy, T cell receptor gene-modified T cell therapy and chimeric antigen receptor natural killer-cell therapy with CAR-T therapy mostly advanced. Nonetheless, the conventional manufacturing process of this therapy has shortcomings in each step that call for improvement. Marked efforts have been invested for its enhancement while notable progresses achieved in the realm of biomaterials application. With CAR-T therapy as a prime example, the aim of this review is to comprehensively discuss the various biomaterials used in cell immunotherapy, their roles in regulating immune cells, and their potential for breakthroughs in cancer treatment from gene transduction to efficacy enhancement. This article additionally addressed widely adopted animal models for efficacy evaluating.

A BRD4-Targeting Photothermal Agent for Controlled Protein Degradation

BRD4 protein plays a pivotal role in cell cycle regulation and differentiation. Disrupting the activity of BRD4 has emerged as a promising strategy for inhibiting the growth and proliferation of cancer cells. Herein, we introduced a BRD4-targeting photothermal agent for controlled protein degradation, aiming to enhance low-temperature photothermal therapy (PTT) for cancer treatment. By incorporating a BRD4 protein inhibitor into a cyanine dye scaffold, the photothermal agent specifically bond to the bromodomain of BRD4. Upon low power density laser irradiation, the agent induced protein degradation, directly destroying the BRD4 structure and inhibiting its transcriptional regulatory function. This strategy not only prolonged the retention time of the photothermal agent in cancer cells but also confined the targeted protein degradation process solely to the tumor tissue, minimizing side effects on normal tissues through the aid of exogenous signals. This work established a simple and feasible platform for future PTT agent design in clinical cancer treatment.

Synergistic meso-β regulation of porphyrins: squeezing the band gap into the near-infrared I/II region

The development of novel near-infrared (NIR) materials with extremely small energy gaps and high stability is highly desirable in bioimaging and phototherapy. Here we report an effective strategy for narrowing the energy gaps of porphyrins by synergistic regulation of meso/β substituents. The novel NIR absorbing/emitting meso-alkynyl naphthoporphyrins (Zn-TNP and Pt-TNP) are synthesized via the retro-Diels-Alder reaction. X-ray crystallography analysis confirms the highly distorted structures of the complexes. Both compounds exhibit intense Q bands around 800 nm, while Zn-TNP shows deep NIR fluorescence at 847 nm. Pt-TNP displays NIR-II room temperature phosphorescence peaking at 1106 nm with an extremely large Stokes shift of 314 nm, which are the longest wavelengths observed among the reported platinum porphyrinoids. Furthermore, Pt-TNP shows remarkable photostability and a notable capacity for synchronous singlet oxygen and heat generation under NIR light irradiation, demonstrating potential in combined photodynamic/photothermal therapy. A theoretical analysis reveals the progressive lifting of the HOMO by the β-fused benzene ring, the decrease of the LUMO upon meso-alkynyl substitution, and energy-releasing pathways varying with metal ions. This dual regulation approach demonstrates great promise in designing innovative multifunctional NIR porphyrin materials.

Designing Mesoporous Prussian Blue@zinc Phosphate Nanoparticles with Hierarchical Pores for Varisized Guest Delivery and Photothermally-Augmented Chemo-Starvation Therapy

Background

With the rapid development of nanotechnology, constructing a multifunctional nanoplatform that can deliver various therapeutic agents in different departments and respond to endogenous/exogenous stimuli for multimodal synergistic cancer therapy remains a major challenge to address the inherent limitations of chemotherapy.

Methods

Herein, we synthesized hollow mesoporous Prussian Blue@zinc phosphate nanoparticles to load glucose oxidase (GOx) and DOX (designed as HMPB-GOx@ZnP-DOX NPs) in the non-identical pore structures of their HMPB core and ZnP shell, respectively, for photothermally augmented chemo-starvation therapy.

Results

The ZnP shell coated on the HMPB core, in addition to providing space to load DOX for chemotherapy, could also serve as a gatekeeper to protect GOx from premature leakage and inactivation before reaching the tumor site because of its degradation characteristics under mild acidic conditions. Moreover, the loaded GOx can initiate starvation therapy by catalyzing glucose oxidation while causing an upgradation of acidity and H2O2 levels, which can also be used as forceful endogenous stimuli to trigger smart delivery systems for therapeutic applications. The decrease in pH can improve the pH-sensitivity of drug release, and O2 can be supplied by decomposing H2O2 through the catalase-like activity of HMPBs, which is beneficial for relieving the adverse conditions of anti-tumor activity. In addition, the inner HMPB also acts as a photothermal agent for photothermal therapy and the generated hyperthermia upon laser irradiation can serve as an external stimulus to further promote drug release and enzymatic activities of GOx, thereby enabling a synergetic photothermally enhanced chemo-starvation therapy effect. Importantly, these results indicate that HMPB-GOx@ZnP-DOX NPs can effectively inhibit tumor growth by 80.31% and exhibit no obvious systemic toxicity in mice.

Conclusion

HMPB-GOx@ZnP-DOX NPs can be employed as potential theranostic agents that incorporate multiple therapeutic modes to efficiently inhibit tumors.

A novel nanodrug for the sensitization of photothermal chemotherapy for breast cancer in vitro

Owing to the complexity of tumor treatment, clinical tumor treatment has evolved from a single treatment mode to multiple combined treatment modes. Reducing the tolerance of tumors to heat and the toxicity of chemotherapy drugs to the body, as well as increasing the sensitivity of tumors to photothermal therapy and chemotherapy drugs, are key issues that urgently need to be addressed in the current cancer treatment. In this work, polylactic acid-based drug nanoparticles (PLA@DOX/GA/ICG) were synthesized with good photothermal conversion ability by encapsulating the water-soluble anticancer drug doxorubicin (DOX), photothermal conversion agent indocyanine green (ICG) and liposoluble drug gambogic acid (GA) using a double emulsion method. The preparation process of PLA@DOX/GA/ICG was examined. Gambogic acid entrapped in PLA@DOX/GA/ICG nanoparticles could act as an HSP90 protein inhibitor to achieve bidirectional sensitization to chemotherapy and photothermal therapy under 808 nm laser irradiation for the first time, effectively ablating breast cancer cells in vitro. This nanodrug was expected to be used for the efficient treatment of tumors.

Gold Nanoparticles-Modified 2D Self-Assembled Amphiphilic Peptide Nanosheets with High Biocompatibility and Photothermal Therapy Efficiency

Amphiphilic peptides have garnered significant attention due to their highly designable and self-assembling behaviors. Self-assembled peptides hold excellent potential in various fields such as biosensing, environmental monitoring, and drug delivery, owing to their remarkable biological, physical, and chemical properties. While nanomaterials formed by peptide self-assembly have found widespread use in biomedical applications, the development of 2D peptide nanosheets based on the self-assembly of amphiphilic peptides remains challenging in terms of rational design and morphology modulation. In this study, rationally designed amphiphilic peptide molecules are self-assembled into peptide nanosheets (PNS) under specific conditions to encapsulate gold nanoparticles (AuNPs), resulting in the formation of AuNPs/PNS hybrid materials with high photothermal conversion efficiency. The findings demonstrate that 2D PNS enhances the overall photothermal therapy effect of the nanohybrid materials due to their larger hosting area for AuNPs and higher biocompatibility. The well-designed amphiphilic peptides in this study offer insights into the structural design and functional modulation of self-assembled molecules. In addition, the constructed biomimetic-functional 2D inorganic/organic nanohybrid materials hold potential applications in biomedical engineering.

Functional hydrogels for hepatocellular carcinoma: therapy, imaging, and in vitro model

Hepatocellular carcinoma (HCC) is among the most common malignancies worldwide and is characterized by high rates of morbidity and mortality, posing a serious threat to human health. Interventional embolization therapy is the main treatment against middle- and late-stage liver cancer, but its efficacy is limited by the performance of embolism, hence the new embolic materials have provided hope to the inoperable patients. Especially, hydrogel materials with high embolization strength, appropriate viscosity, reliable security and multifunctionality are widely used as embolic materials, and can improve the efficacy of interventional therapy. In this review, we have described the status of research on hydrogels and challenges in the field of HCC therapy. First, various preparation methods of hydrogels through different cross-linking methods are introduced, then the functions of hydrogels related to HCC are summarized, including different HCC therapies, various imaging techniques, in vitro 3D models, and the shortcomings and prospects of the proposed applications are discussed in relation to HCC. We hope that this review is informative for readers interested in multifunctional hydrogels and will help researchers develop more novel embolic materials for interventional therapy of HCC.

Near-Infrared Light-Driving Organic Photothermal Agents with an 88.9% Photothermal Conversion Efficiency for Image-Guided Synergistic Phototherapy

Photothermal agents (PTAs) with desirable near-infrared (NIR) absorption and excellent photothermal conversion efficiency (PCE) are ideal candidates for cancer treatment. However, numerous PTAs still require high-intensity and long-duration laser irradiation to completely ablate the tumor during the photothermal therapy (PTT) process, resulting in light damage to healthy skin and tissue as well as limiting their biomedical applications. Integrating intense NIR absorption and high PCE into a single small-molecule PTA is an important prerequisite for realizing efficient PTT, but is a serious challenge. Herein, a series of donor-acceptor type PTAs (CC1 to NC4) are designed through a molecular engineering strategy. Theoretical calculations and experimental results show that the NIR absorption and photothermal effect from CC1 to NC4 are significantly enhanced as expected. Notably, NC4 nanoparticles exhibit intense NIR absorption, superhigh PCE of up to 88.9% for PTT, photoacoustic imaging and photothermal imaging, and effective reactive oxygen species generation for photodynamic therapy (PDT). The superior PTT/PDT synergistic phototherapeutic efficacy is well demonstrated by the complete elimination of tumor in vivo upon one-time, low-intensity, and short-duration laser irradiation (808 nm, 330 mW cm-2, and 3 min). This work provides a valuable guideline for rational design of PTAs for cancer phototherapy.

Harnessing the potential of hydrogels for advanced therapeutic applications: current achievements and future directions

The applications of hydrogels have expanded significantly due to their versatile, highly tunable properties and breakthroughs in biomaterial technologies. In this review, we cover the major achievements and the potential of hydrogels in therapeutic applications, focusing primarily on two areas: emerging cell-based therapies and promising non-cell therapeutic modalities. Within the context of cell therapy, we discuss the capacity of hydrogels to overcome the existing translational challenges faced by mainstream cell therapy paradigms, provide a detailed discussion on the advantages and principal design considerations of hydrogels for boosting the efficacy of cell therapy, as well as list specific examples of their applications in different disease scenarios. We then explore the potential of hydrogels in drug delivery, physical intervention therapies, and other non-cell therapeutic areas (e.g., bioadhesives, artificial tissues, and biosensors), emphasizing their utility beyond mere delivery vehicles. Additionally, we complement our discussion on the latest progress and challenges in the clinical application of hydrogels and outline future research directions, particularly in terms of integration with advanced biomanufacturing technologies. This review aims to present a comprehensive view and critical insights into the design and selection of hydrogels for both cell therapy and non-cell therapies, tailored to meet the therapeutic requirements of diverse diseases and situations.

A Golgi Apparatus-Targeted Photothermal Agent with Protein Anchoring for Enhanced Cancer Photothermal Therapy

The Golgi apparatus (GA) is central in shuttling proteins from the endoplasmic reticulum to different cellular areas. Therefore, targeting the GA to precisely destroy its proteins through local heat could induce apoptosis, offering a potential avenue for effective cancer therapy. Herein, a GA-targeted photothermal agent based on protein anchoring is introduced for enhanced photothermal therapy of tumor through the modification of near-infrared molecular dye with maleimide derivative and benzene sulfonamide. The photothermal agent can actively target the GA and covalently anchor to its sulfhydryl proteins, thereby increasing its retention within the GA. Under laser irradiation, the heat generated by the photothermal agent efficiently disrupts sulfhydryl proteins in situ, leading to GA dysfunction and ultimately inducing cell apoptosis. In vivo experiments demonstrate that the photothermal agent can precisely treat tumors and significantly reduce side effects.

Making the Brightest Ones Dim: Maximizing the Photothermal Conversion Efficiency of BODIPY-Based Photothermal Agents

The successful implementation of photothermal therapy (PTT) in cancer treatment hinges on the development of highly effective photothermal agents (PTAs). Boron dipyrromethene (BODIPY) dyes, being well known for their high brightness and quantum efficiencies, are the antithesis of PTAs. Nonetheless, a systematic exploration of the photophysics and photothermal characteristics of a series of π-extended BODIPY dyes with high absorptivity in the near-infrared (NIR) region has achieved superior photothermal conversion efficiencies (>90%), in both monomeric state and nanoparticles after encapsulation in a biocompatible polyethyleneglycol 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy-(polyethylene glycol)-2000]. Optimal PTA candidates combine strong NIR absorption provided by extended donor-acceptor conjugation and an optimization of the electronic and steric effects of meso-substituents to maximize photothermal conversion performance. The PTT-optimized meso-CF3-BODIPY, TCF3PEn exhibits exceptional efficacy in inducing cancer cell apoptosis and in vivo tumor ablation using low-power NIR laser irradiation (0.3 W cm-2, 808 nm) as well as excellent biological safety, underscoring its potential for advancing light-induced cancer therapies.

Silver sulfide anchored bismuth molybdate p-n heterojunction nano-coating with excellent photo-thermal self-healing performance

In this research, a self-healing nano-coating with excellent photo-thermal response to near-infrared (NIR) laser is prepared. This coating incorporates silver sulfide anchored bismuth molybdate (Ag2S@Bi2MoO6) into a shape memory epoxy resin to achieve for a good photo-thermal conversion capability. The Ag2S@Bi2MoO6 p-n heterojunction could photo-generate more electron-holes pairs under the NIR laser irradiation. Also, it shows a wider absorption range of visible light, leading to effectively absorb the light energy, generate enough heat to induce the shape memory recovery in the coating, and seal the scratch. The results indicate that the temperature of EP-1 % Ag2S@Bi2MoO6 coating has reached about 88 °C, while good self-healing and anti-corrosion properties with a self-healing rate of 88.41 % have been achieved. Furthermore, calculations based on Density Functional Theory and Finite Element Method pointed out that the formation of p-n heterojunction effectively has enhanced the photo-thermal effect. This research opens a new way for developing self-healing coatings with an ultra-fast response time and high self-healing efficiency.

Genetic Engineering Bacillus thuringiensis Enable Melanin Biosynthesis for Anti-Tumor and Anti-Inflammation

Collaboration between cancer treatment and inflammation management has emerged as an integral facet of comprehensive cancer care. Nevertheless, the development of interventions concurrently targeting both inflammation and cancer has encountered significant challenges stemming from various external factors. Herein, a bioactive agent synthesized by genetically engineering melanin-producing Bacillus thuringiensis (B. thuringiensis) bacteria, simultaneously achieves eco-friendly photothermal agent and efficient reactive oxygen/nitrogen species (RONS) scavenger benefits, perfectly tackling present toughies from inflammation to cancer therapies. The biologically derived melanin exhibits exceptional photothermal-conversion performance, facilitating potent photonic hyperthermia that effectively eradicates tumor cells and tissues, thereby impeding tumor growth. Additionally, the RONS-scavenging properties of melanin produced by B. thuringiensis bacteria contribute to inflammation reduction, augmenting the efficacy of photothermal tumor repression. This study presents a representative paradigm of genetic engineering in B. thuringiensis bacteria to produce functional agents tailored for diverse biomedical applications, encompassing inflammation and cancer therapy.

Harnessing Bacterial Membrane Components for Tumor Vaccines: Strategies and Perspectives

Tumor vaccines stand at the vanguard of tumor immunotherapy, demonstrating significant potential and promise in recent years. While tumor vaccines have achieved breakthroughs in the treatment of cancer, they still encounter numerous challenges, including improving the immunogenicity of vaccines and expanding the scope of vaccine application. As natural immune activators, bacterial components offer inherent advantages in tumor vaccines. Bacterial membrane components, with their safer profile, easy extraction, purification, and engineering, along with their diverse array of immune components, activate the immune system and improve tumor vaccine efficacy. This review systematically summarizes the mechanism of action and therapeutic effects of bacterial membranes and its derivatives (including bacterial membrane vesicles and hybrid membrane biomaterials) in tumor vaccines. Subsequently, the authors delve into the preparation and advantages of tumor vaccines based on bacterial membranes and hybrid membrane biomaterials. Following this, the immune effects of tumor vaccines based on bacterial outer membrane vesicles are elucidated, and their mechanisms are explained. Moreover, their advantages in tumor combination therapy are analyzed. Last, the challenges and trends in this field are discussed. This comprehensive analysis aims to offer a more informed reference and scientific foundation for the design and implementation of bacterial membrane-based tumor vaccines.

Application of photothermal effects of nanomaterials in food safety detection

Numerous nanomaterials endowed with outstanding light harvesting and photothermal conversion abilities have been extensively applied in various fields, such as photothermal diagnosis and therapy, trace substance detection, and optical imaging. Although photothermal detection methods have been established utilizing the photothermal effect of nanomaterials in recent years, there is a scarcity of reviews regarding their application in food safety detection. Herein, the recent advancements in the photothermal conversion mechanism, photothermal conversion efficiency calculation, and preparation method of photothermal nanomaterials were reviewed. In particular, the application of photothermal nanomaterials in various food hazard analyses and the newly established photothermal detection methods were comprehensively discussed. Moreover, the development and promising future trends of photothermal nanomaterial-based detection methods were discussed, which provide a reference for researchers to propose more effective, sensitive, and accurate detection methods.

An All-Rounder for NIR-II Phototheranostics: Well-Tailored 1064 nm-Excitable Molecule for Photothermal Combating of Orthotopic Breast Cancer

The second near-infrared (NIR-II, 1000-1700 nm) light-activated organic photothermal agent that synchronously enables satisfying NIR-II fluorescence imaging is highly warranted yet rather challenging on the basis of the overwhelming nonradiative decay. Herein, such an agent, namely TPABT-TD, was tactfully designed and constructed via employing benzo[c]thiophene moiety as bulky electron donor/π-bridge and tailoring the peripheral molecular rotors. Benefitting from its high electron donor-acceptor strength and finely modulated intramolecular motion, TPABT-TD simultaneously exhibits ultralong absorption in NIR-II region, intense fluorescence emission in the NIR-IIa (1300-1500 nm) region as nanoaggregates, and high photothermal conversion upon 1064 nm laser irradiation. Those intrinsic advantages endow TPABT-TD nanoparticles with prominent fluorescence/photoacoustic/photothermal trimodal imaging-guided NIR-II photothermal therapy against orthotopic 4T1 breast tumor with negligible adverse effect.

Gold(III) Porphyrin-Metal-Polyphenolic Nanocomplexes: Breaking Intracellular Redox Environment for Enhancing Mild-Temperature Photothermal Therapy

Photothermal therapy (PTT) is a promising clinical antitumor strategy. However, local hyperthermia inevitably induces heat damage to adjacent normal tissues, while alternative mild-temperature therapy (MPTT, T < 45 °C) is also inefficient due to the overexpressed hyperthermia-induced heat shock proteins (HSPs) by cancer cells. Therefore, developing PTT strategies with minimizing damage to healthy tissues with improved cellular temperature sensitivity is extremely valuable for clinical application. Herein, we proposed the strategy of disrupting the intracellular redox environment via destroying the ROS-defending systems to promote MPTT. The gold(III) porphyrin-Fe3+-tannic acid nanocomplexes (AuTPP@TA-Fe NPs) were achieved via interfacial cohesion and supramolecular assembly of bioadhesive species, which could trigger the Fenton reaction to produce ·OH radicals and downregulation of reductive TrxR enzyme and mitochondrial chaperone protein Hsp60. The aggravation of oxides and the inactivation of Hsp60 provide favorable pathways for impeding the heat shock-induced self-repair mechanism of cancer cells, which strengthens AuTPP@TA-Fe NPs mediated MPTT.

Tumor Cell-Targeting and Tumor Microenvironment-Responsive Nanoplatforms for the Multimodal Imaging-Guided Photodynamic/Photothermal/Chemodynamic Treatment of Cervical Cancer

Purpose

Phototherapy, known for its high selectivity, few side effects, strong controllability, and synergistic enhancement of combined treatments, is widely used in treating diseases like cervical cancer.

Methods

In this study, hollow mesoporous manganese dioxide was used as a carrier to construct positively charged, poly(allylamine hydrochloride)-modified nanoparticles (NPs). The NP was efficiently loaded with the photosensitizer indocyanine green (ICG) via the addition of hydrogen phosphate ions to produce a counterion aggregation effect. HeLa cell membrane encapsulation was performed to achieve the final M-HMnO2@ICG NP. In this structure, the HMnO2 carrier responsively degrades to release ICG in the tumor microenvironment, self-generates O2 for sensitization to ICG-mediated photodynamic therapy (PDT), and consumes GSH to expand the oxidative stress therapeutic effect [chemodynamic therapy (CDT) + PDT]. The ICG accumulated in tumor tissues exerts a synergistic PDT/photothermal therapy (PTT) effect through single laser irradiation, improving efficiency and reducing side effects. The cell membrane encapsulation increases nanomedicine accumulation in tumor tissues and confers an immune evasion ability. In addition, high local temperatures induced by PTT can enhance CDT. These properties of the NP enable full achievement of PTT/PDT/CDT and targeted effects.

Results

Mn2+ can serve as a magnetic resonance imaging agent to guide therapy, and ICG can be used for photothermal and fluorescence imaging. After its intravenous injection, M-HMnO2@ICG accumulated effectively at mouse tumor sites; the optimal timing of in-vivo laser treatment could be verified by near-infrared fluorescence, magnetic resonance, and photothermal imaging. The M-HMnO2@ICG NPs had the best antitumor effects among treatment groups under near-infrared light conditions, and showed good biocompatibility.

Conclusion

In this study, we designed a nano-biomimetic delivery system that improves hypoxia, responds to the tumor microenvironment, and efficiently loads ICG. It provides a new economical and convenient strategy for synergistic phototherapy and CDT for cervical cancer.

Multiple Synergistic Effects of the Microglia Membrane-Bionic Nanoplatform on Mediate Tumor Microenvironment Remodeling to Amplify Glioblastoma Immunotherapy

Glioblastoma (GBM) is a lethal brain tumor with high levels of malignancy. Most chemotherapy agents show serious systemic cytotoxicity and restricted delivery effectiveness due to the impediments of the blood-brain barrier (BBB). Immunotherapy has developed great potential for aggressive tumor treatments. Disappointingly, its efficacy against GBM is hindered by the immunosuppressive tumor microenvironment (TME) and BBB. Herein, a multiple synergistic immunotherapeutic strategy against GBM was developed based on the nanomaterial-biology interaction. We have demonstrated that this BM@MnP-BSA-aPD-1 can transverse the BBB and target the TME, resulting in amplified synergetic effects of metalloimmunotherapy and photothermal immunotherapy (PTT). The journey of this nanoformulation within the TME contributed to the activation of the stimulator of the interferon gene pathway, the initiation of the immunogenic cell death effect, and the inhibition of the programmed cell death-1/programmed cell death ligand 1 (PD-1/PD-L1) signaling axis. This nanomedicine revitalizes the immunosuppressive TME and evokes the cascade effect of antitumor immunity. Therefore, the combination of BM@MnP-BSA-aPD-1 and PTT without chemotherapeutics presents favorable benefits in anti-GBM immunotherapy and exhibits immense potential for clinical translational applications.