Strategies for efficient photothermal therapy at mild temperatures: Progresses and challenges

Injectable Therapeutic Hydrogel with H2O2 Self-Supplying and GSH Consumption for Synergistic Chemodynamic/Low-Temperature Photothermal Inhibition of Postoperative Tumor Recurrence and Wound Infection

Postoperative tumor recurrence and wound infection remain significant clinical challenges in surgery, often requiring adjuvant therapies. The combination treatment of photothermal therapy (PTT) and chemodynamic therapy (CDT) has proven to be effective in cancer treatment and wound infection. However, the hyperthermia during PTT increases the risk of normal tissue damage, severely impeding its application. Moreover, the efficacy of CDT is limited by insufficient hydrogen peroxide (H2O2) and excessive glutathione (GSH) levels at tumor or infection sites. Herein, an injectable and multifunctional CuO2@Au hydrogel system (CuO2@Au Gel) is developed for synergistic CDT and low-temperature PTT (LTPTT) to prevent tumor recurrence and bacterial wound infections. CuO2@Au Gel is constructed by embedding therapeutic CuO2@Au into low-melting point agarose hydrogel. In vitro and in vivo experiments confirm that the CuO2@Au in CuO2@Au Gel is capable of self-supplying H2O2 and depleting GSH, exhibiting effective CDT effect in acidic tumor or bacterial infected microenvironment. Additionally, it exhibits favorable photothermal conversion ability, inducing localized temperature elevation and synergistically enhancing CDT efficiency. The prepared CuO2@Au Gel demonstrates efficient tumor ablation capability in post-surgery recurrence mouse models and exhibits promising anti-infective efficiency in bacterial infection wound models, indicating significant potential in adjuvant therapy for post-surgical treatment and recovery.

NIR triggered polydopamine coated cerium dioxide nanozyme for ameliorating acute lung injury via enhanced ROS scavenging

Acute lung injury (ALI) is a life threatening disease in critically ill patients, and characterized by excessive reactive oxygen species (ROS) and inflammatory factors levels in the lung. Multiple evidences suggest that nanozyme with diversified catalytic capabilities plays a vital role in this fatal lung injury. At present, we developed a novel class of polydopamine (PDA) coated cerium dioxide (CeO2) nanozyme (Ce@P) that acts as the potent ROS scavenger for scavenging intracellular ROS and suppressing inflammatory responses against ALI. Herein, we aimed to identify that Ce@P combining with NIR irradiation could further strengthen its ROS scavenging capacity. Specifically, NIR triggered Ce@P exhibited the most potent antioxidant and anti-inflammatory behaviors in lipopolysaccharide (LPS) induced macrophages through decreasing the intracellular ROS levels, down-regulating the levels of TNF-α, IL-1β and IL-6, up-regulating the level of antioxidant cytokine (SOD-2), inducing M2 directional polarization (CD206 up-regulation), and increasing the expression level of HSP70. Besides, we performed intravenous (IV) injection of Ce@P in LPS induced ALI rat model, and found that it significantly accumulated in the lung tissue for 6 h after injection. It was also observed that Ce@P + NIR presented the superior behaviors of decreasing lung inflammation, alleviating diffuse alveolar damage, as well as promoting lung tissue repair. All in all, it has developed the strategy of using Ce@P combining with NIR irradiation for the synergistic enhanced treatment of ALI, which can serve as a promising therapeutic strategy for the clinical treatment of ROS derived diseases as well.

Two-photon fluorescence-guided precise photothermal therapy located in a single cancer cell utilizing bifunctional N-doped carbon quantum dots

The utilization of carbon quantum dots (CQDs) for photothermal therapy has emerged as a hot research topic. However, there has been limited research on killing one single cancer cell which is critical in reducing unnecessary damage to the surrounding healthy tissues. In this work, we developed a two-photon fluorescence-guided precise photothermal therapy in a single human malignant melanoma (A375) cancer cell utilizing bifunctional N-doped CQDs. Resulting from the two-photon fluorescence of the CQDs, one single cancer cell can be located and simultaneously destroyed by the photothermal effect of the same CQDs. Specifically, the balanced two-photon absorption cross-section (7000 GM) and photoluminescence quantum yield (8.4%) of the CQDs enable the fluorescence-guided photothermal treatment to be achieved in only 5 s under the irradiation of 800 nm laser of 27.5 mW, much faster than the control experiment without the guidance of fluorescence. The heat generated by the aggregated CQDs is in sufficient amounts while being confined in a small area, as evidenced by the numerical simulations and photothermal experiments, to limit the range of thermal treatment in the cells. This work provides a new approach for realizing photothermal therapy with minimal damage and establishes a new application scenario of CQDs for precise tumor ablation.

Biosynthesis of CuTe Nanorods with Large Molar Extinction Coefficients for NIR-II Photoacoustic Imaging

Photoacoustic imaging (PAI) in the second near-infrared region (NIR-II), due to deeper tissue penetration and a lower background interference, has attracted widespread concern. However, the development of NIR-II nanoprobes with a large molar extinction coefficient and a high photothermal conversion efficiency (PCE) for PAI and photothermal therapy (PTT) is still a big challenge. In this work, the NIR-II CuTe nanorods (NRs) with large molar extinction coefficients ((1.31 ± 0.01) × 108 cm-1·M-1 at 808 nm, (7.00 ± 0.38) × 107 cm-1·M-1 at 1064 nm) and high PCEs (70% at 808 nm, 48% at 1064 nm) were synthesized by living Staphylococcus aureus (S. aureus) cells as biosynthesis factories. Due to the strong light-absorbing and high photothermal conversion ability, the in vitro PA signals of CuTe NRs were about 6 times that of indocyanine green (ICG) in both NIR-I and NIR-II. In addition, CuTe NRs could effectively inhibit tumor growth through PTT. This work provides a new strategy for developing NIR-II probes with large molar extinction coefficients and high PCEs for NIR-II PAI and PTT.

A carrier-free tri-component nanoreactor for multi-pronged synergistic cancer therapy

Non-invasive therapies such as photodynamic therapy (PDT) and chemodynamic therapy (CDT) have received wide attention due to their low toxicity and side effects, but their efficacy is limited by the tumor microenvironment (TME), and monotherapy cannot achieve satisfactory efficacy. In this work, a multifunctional nanoparticle co-assembled from oleanolic acid (OA), chlorin e6 (Ce6) and hemin was developed. The as-constructed nanoparticle named OCH with diameters of around 130 nm possessed good biostability, pH/GSH dual-responsive drug release properties, and remarkable cellular internalization and tumor accumulation capabilities. OCH exhibited prominent catalytic activities to generate •OH, deplete GSH, and produce O2 to overcome the hypoxia TME, thus potentiating the photodynamic and chemodynamic effect. In addition, OCH can induce the occurrence of ferroptosis in both ferroptosis-sensitive and ferroptosis-resistant cancer cells. The multi-pronged effects of OCH including hypoxia alleviation, GSH depletion, ferroptosis induction, CDT and PDT effects jointly facilitate excellent anticancer effects in vitro and in vivo. Hence, this work will advance the development of safe and effective clinically transformable nanomedicine by employing clinically-applied agents to form drug combinations for efficient multi-pronged combination cancer therapy.

Engineering a hyaluronic acid-encapsulated tumor-targeted nanoplatform with sensitized chemotherapy and a photothermal effect for enhancing tumor therapy

Chemotherapy remains one of the most widely used cancer treatment modalities in clinical practice. However, the characteristic microenvironment of solid tumors severely limits the anticancer efficacy of chemotherapy. In addition, a single treatment modality or one death pathway reduces the antitumor outcome. Herein, tumor-targeting O2 self-supplied nanomodules (CuS@DOX/CaO2-HA) are proposed that not only alleviate tumor microenvironmental hypoxia to promote the accumulation of chemotherapeutic drugs in tumors but also exert photothermal effects to boost drug release, penetration and combination therapy. CuS@DOX/CaO2-HA consists of copper sulfide (CuS)-loaded calcium peroxide (CaO2) and doxorubicin (DOX), and its surface is further modified with HA. CuS@DOX/CaO2-HA underwent photothermal treatment to release DOX and CaO2. Hyperthermia accelerates drug penetration to enhance chemotherapeutic efficacy. The exposed CaO2 reacts with water to produce Ca2+, H2O2 and O2, which sensitizes cells to chemotherapy through mitochondrial damage caused by calcium overload and a reduction in drug efflux via the alleviation of hypoxia. Moreover, under near infrared (NIR) irradiation, CuS@DOX/CaO2-HA initiates a pyroptosis-like cell death process in addition to apoptosis. In vivo, CuS@DOX/CaO2-HA demonstrated high-performance antitumor effects. This study provides a new strategy for synergistic enhancement of chemotherapy in hypoxic tumor therapy via combination therapy and multiple death pathways.

Engineered macrophage-derived cellular vesicles for NIR-II fluorescence imaging-guided precise cancer photo-immunotherapy

Significant progress has been made in cancer immunotherapy; however, challenges such as interpatient variability, limited treatment response, and severe side effects persist. Although nanoimmunotherapy has emerged as a promising approach, the construction of precise and efficient nanosystems remain formidable challenges. Herein, a multifunctional nanoplatform was developed using macrophage-derived cellular vesicles (MCVs) for NIR-II imaging-guided precise cancer photo-immunotherapy. MCVs exhibited excellent tumor targeting and TAMs re-education effects, serving as both delivery carriers and therapeutic agents. Through amide bond, indocyanine green (ICG) was conjugated to the surface of MCVs, enabling in vivo tracking of MCVs distribution. Notably, ICG exhibited dual functionality as a NIR-II fluorescent agent and possessed photodynamic and photothermal effects, enabling the conversion of light energy into chemical or heat energy to eliminate tumor cells. This precision phototherapy triggered immunogenic cell death (ICD) of tumor, thereby activating the anti-tumor immune response. Additionally, MCVs loaded with R848, a toll-like receptor agonist, augmented the ICD-induced anti-tumor immunity. Animal experiments confirmed that MCVs-mediated photoimmunotherapy promoted T cell infiltration, inhibited tumor growth, and improved survival rates. In conclusion, we have developed a promising precision immunotherapy strategy capable of enhancing the immune response while mitigating off-target effects. These findings offer encouraging prospects for clinical translation.

Gene and Photothermal Combination Therapy: Principle, Materials, and Amplified Anticancer Intervention

Gene therapy (GT) and photothermal therapy (PTT) have emerged as promising alternatives to chemotherapy and radiotherapy for cancer treatment, offering noninvasiveness and reduced side effects. However, their efficacy as standalone treatments is limited. GT exhibits slow response rates, while PTT is confined to local tumor ablation. The convergence of GT and PTT, known as GT-PTT, facilitated by photothermal gene nanocarriers, has attracted considerable attention across various disciplines. In this integrated approach, GT reciprocates PTT by sensitizing cellular response to heat, while PTT benefits GT by improving gene translocation, unpacking, and expression. Consequently, this integration presents a unique opportunity for cancer therapy with rapid response and improved effectiveness. Extensive efforts over the past few years have been dedicated to the development of GT-PTT, resulting in notable achievements and rapid progress from the laboratory to potential clinical applications. This comprehensive review outlines recent advances in GT-PTT, including synergistic mechanisms, material systems, imaging-guided therapy, and anticancer applications. It also explores the challenges and future prospects in this nascent field. By presenting innovative ideas and insights into the implementation of GT-PTT for enhanced cancer therapy, this review aims to inspire further progress in this promising area of research.

UV-C driven reduction of nanographene oxide opens path for new applications in phototherapy

The main challenges associated to the application of graphene-based materials (GBM) in phototherapy are obtaining particles with lateral nanoscale dimensions and water stability that present high near-infrared (NIR) absorption. Nanosized graphene oxide (GOn) is stable in aqueous dispersion, due to the oxygen functionalities on its surface, but possesses low photothermal efficiency in NIR region. GOn total reduction originates reduced nanographene oxide (rGOn) that presents high NIR absorption, but poor water stability. In this work, we produced a partially reduced nanographene oxide (p-rGOn) by GOn photoreduction using ultraviolet radiation (UV-C), yielding nanometric particles that preserve the original water stability, but acquire high light-to-heat conversion efficiency. GOn and p-rGOn presented mean particle sizes of 170 ± 81 nm and 188 ± 99 nm, respectively. 8 h of UV-C irradiation allowed to obtain a p-rGOn stable for up 6 months in water, with a zeta potential of -32.3 ± 1.3 mV. p-rGOn water dispersions have shown to absorb NIR radiation, reaching 52.7 °C (250 µg mL-1) after 30 min NIR irradiation. Chemical characterization of p-rGOn showed a decrease in the number of characteristic oxygen functional groups, confirming GOn partial reduction. Furthermore, p-rGOn (250 µg mL-1) didn't cause any cytotoxicity (ISO10993-5:2009(E)) towards human skin fibroblasts (HFF-1) and human skin keratinocytes (HaCat), after 24 and 48 h incubation. An innovative custom-built NIR LED-system has been developed and validated for p-rGOn photothermal effect evaluation. Finally, exposure to p-rGOn+NIR-LEDs has caused no cytotoxicity towards HFF-1 or HaCat cells, revealing its potential to be used as a safe therapy.

Lonidamine liposomes to enhance photodynamic and photothermal therapy of hepatocellular carcinoma by inhibiting glycolysis

Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has great promise in the treatment of cancer. However, there are many obstacles that can restrict the therapeutic efficacy of phototherapy. The hypoxic tumor microenvironment can restrict the production of reactive oxygen species (ROS) in PDT. As for PTT, the thermotolerance of cancer cells may lead to ineffective PTT. In this study, IR780 and glycolysis inhibitor lonidamine (LND)-encapsulated liposomes are prepared for photodynamic and photothermal therapy of hepatocellular carcinoma. IR780 can be used as a photosensitizer and photothermal agent for simultaneous PDT and PTT after being irradiated with 808 nm laser. LND can reduce the oxygen consumption of cancer cells by inhibiting glycolysis, which will relieve tumor hypoxia and produce more ROS for PDT. On the other hand, energy supply can be blocked by LND-induced glycolysis inhibition, which will inhibit the production of heat shock proteins (HSPs), reduce the thermotolerance of tumor cells, and finally enhance the therapeutic efficacy of PTT. The enhanced PTT is studied by measuring intracellular HSPs, ATP level, and mitochondrial membrane potential. The antitumor effect of IR780 and LND co-loaded liposomes is extensively investigated by in vitro and in vivo experiments. This research provides an innovative strategy to simultaneously enhance the therapeutic efficacy of PDT and PTT by inhibiting glycolysis, which is promising for future creative approaches to cancer phototherapy.

A dipyridophenazine Ni(II) dithiolene complex as a dual-acting cancer phototherapy agent activatable within the phototherapeutic window

A combination of photodynamic therapy (PDT) and photothermal therapy (PTT) within the phototherapeutic window (600-900 nm) can lead to significantly enhanced therapeutic outcomes, surpassing the efficacy observed with PDT or PTT alone in cancer phototherapy. Herein, we report a novel small-molecule mixed-ligand Ni(II)-dithiolene complex (Ni-TDD) with a dipyridophenazine ligand, demonstrating potent red-light PDT and significant near-infrared (NIR) light mild-temperature PTT activity against cancer cells and 3D multicellular tumour spheroids (MCTSs). The four-coordinate square planar complex exhibited a moderately intense absorption band (ε ∼ 3700 M-1cm-1) centered around 900 nm and demonstrated excellent dark and photostability in an aqueous phase. Ni-TDD induced a potent red-light (600-720 nm) PDT effect on HeLa cancer cells (IC50 = 1.8 μM, photo irritation factor = 44), triggering apoptotic cell death through efficient singlet oxygen generation. Ni-TDD showed a significant intercalative binding affinity towards double-helical calf thymus DNA, resulting in a binding constant (Kb) ∼ 106 M-1. The complex induced mild hyperthermia and exerted a significant mild-temperature PTT effect on MDA-MB-231 cancer cells upon irradiation with 808 nm NIR light. Simultaneous irradiation of Ni-TDD-treated HeLa MCTSs with red and NIR light led to a remarkable synergistic inhibition of growth, exceeding the effects of individual irradiation, through the generation of singlet oxygen and mild hyperthermia. Ni-TDD displayed minimal toxicity towards non-cancerous HPL1D and L929 cells, even at high micromolar concentrations. This is the first report of a Ni(II) complex demonstrating red-light PDT activity and the first example of a first-row transition metal complex exhibiting combined PDT and PTT effects within the clinically relevant phototherapeutic window. Our findings pave the way for designing and developing metal-dithiolene complexes as dual-acting cancer phototherapy agents using long wavelength light for treating solid tumors.

Mild photothermal therapy assist in promoting bone repair: Related mechanism and materials

Achieving precision treatment in bone tissue engineering (BTE) remains a challenge. Photothermal therapy (PTT), as a form of precision therapy, has been extensively investigated for its safety and efficacy. It has demonstrated significant potential in the treatment of orthopedic diseases such as bone tumors, postoperative infections and osteoarthritis. However, the high temperatures associated with PTT can lead to certain limitations and drawbacks. In recent years, researchers have explored the use of biomaterials for mild photothermal therapy (MPT), which offers a promising approach for addressing these limitations. This review provides a comprehensive overview of the mechanisms underlying MPT and presents a compilation of photothermal agents and their utilization strategies for bone tissue repair. Additionally, the paper discusses the future prospects of MPT-assisted bone tissue regeneration, aiming to provide insights and recommendations for optimizing material design in this field.

A covalent organic framework-derived M1 macrophage mimic nanozyme for precise tumor-targeted imaging and NIR-II photothermal catalytic chemotherapy

Nanoprobes for efficient tumor-targeted imaging and therapy are urgently needed for clinical tumor theranostics. Herein, inspired by the heterogeneity of the tumor microenvironment, we report a covalent organic framework (COF)-derived biomimetic nanozyme for precise tumor-targeted imaging and NIR-II photothermal-catalysis-enhanced chemotherapy (PTCEC). Using a crystalline nanoscale COF as the precursor, a peroxidase-like porous N-doped carbonous nanozyme (PNC) was obtained, which was cloaked with an M1 macrophage cell membrane (M1m) to create a multifunctional biomimetic nanoprobe for tumor-targeted imaging and therapy. The M1m coating enabled the nanoprobe to target cancer cells and tumor tissues for highly efficient tumor imaging and drug delivery. The peroxidase-like activity of the PNC allowed for the conversion of intratumoral H2O2 into toxic ˙OH that synergized with its NIR-II photothermal effect to strengthen the chemotherapy. Therefore, highly efficient tumor-targeted imaging and NIR-II PTCEC were realized with an M1 macrophage mimic nanoprobe. This work provides a feasible tactic for a biomimetic theranostic nanoprobe and will inspire the development of new bioactive nanomaterials for clinical tumor theranostic applications.

Resveratrol-Coated Gold Nanoflowers for CT Imaging and Apoptosis/Photothermal Synergistic Therapy of Malignant Melanoma

In the past decade, photothermal therapy (PTT) of tumors based on gold nanomaterials has been widely studied because of their strong extinction ability and high photothermal conversion ability in the near-infrared (NIR) region. However, related research still faces two problems: First, the biosafety of the surface ligands on gold nanomaterials is not ideal and even has strong toxicity, so the surface modification or shell coating is very necessary; second, gold nanomaterials only have a single PTT function, which requires high temperature to achieve better treatment effect. Therefore, it is necessary to enrich the antitumor function of gold nanomaterials and realize synergistic therapy. Natural polyphenols can combine with each other or other substances through various supramolecular forces, forming shells on the surface of nanomaterials and reducing biotoxicity. In addition, natural polyphenols represented by resveratrol have antitumor activity and can induce apoptosis of tumor cells. Therefore, the surface coating method of gold nanomaterials with natural polyphenols with antitumor activity can effectively solve the above problems. In this work, we prepared resveratrol-coated gold nanoflowers (Au@Res NFs) and applied them to the treatment of malignant melanoma. Resveratrol in Au@Res NFs can induce the apoptosis of tumor cells, and Au@Res NFs can play a role in PTT under an NIR laser. In cell experiments, the synergistic effect of apoptosis/PTT on the A375 cells was extremely strong. In animal experiments, Au@Res NFs enriched in tumor sites identified the location and boundary of tumors by computed tomography (CT). The apoptosis induced by resveratrol had a certain inhibitory effect on tumor growth. Further applying the NIR laser, under the synergistic effect of apoptosis and PTT, the tumors were completely eliminated without recurrence during the experimental period.

A NIR-Activated and Mild-Temperature-Sensitive Nanoplatform with an HSP90 Inhibitor for Combinatory Chemotherapy and Mild Photothermal Therapy in Cancel Cells

Mild photothermal therapy (PTT) shows great potential to treat cancers while avoiding unwanted damage to surrounding normal cells. However, the efficacy of mild PTT is normally moderate because of the low hyperthermia temperature and limited light penetration depth. Chemotherapy has unlimited penetration but often suffers from unsatisfactory efficacy in view of the occurrence of drug resistance, suboptimal drug delivery and release profile. As a result, the combinatory of chemotherapy and mild PTT would integrate their advantages and overcome the shortcomings. Herein, we synthesized an NIR-activatable and mild-temperature-sensitive nanoplatform (BDPII-gel@TSL) composed of temperature-sensitive liposomes (TSL), heat shock protein 90 (HSP90) inhibitor (geldanamycin) and photothermal agent (BDPII), for dual chemotherapy and mild PTT in cancer cells. BDPII, constructed with donor-acceptor moieties, acts as an excellent near-infrared (NIR) photothermal agent (PTA) with a high photothermal conversion efficiency (80.75%). BDPII-containing TSLs efficiently produce a mild hyperthermia effect (42 °C) under laser irradiation (808 nm, 0.5 W cm-2). Importantly, the phase transformation of TSL leads to burst release of geldanamycin from BDPII-gel@TSL, and this contributes to down-regulation of the overexpression of HSP90, ensuring efficient inhibition of cancer cell growth. This research provides a dual-sensitive synergistic therapeutic strategy for cancer cell treatment.

Photothermal Propelling and Pyroelectric Potential-Promoted Cell Internalization of Janus Nanoparticles and Pyroelectrodynamic Tumor Therapy

Cancer phototherapy experiences limitations in tissue diffusion and cell internalization of phototherapeutic agents and dose-dependent side effects. Herein, Janus pyroelectric nanoparticles (NPs) are designed to generate self-powered motion and built-in electric fields to overcome the delivery barriers. Polydopamine (PDA) layers are partially coated on tetragonal BaTiO3 (tBT) NPs to prepare Janus tBT@PDA, and Au NPs are deposited on the PDA caps to obtain Janus tBT@PDA-Au NPs. Near-infrared (NIR) illumination of tBT@PDA-Au builds in situ pyroelectric potentials on NPs, which selectively affect the membrane potential of tumor cells rather than normal cells to enhance tumor cell internalization and produce reactive oxygen species (ROS) for pyroelectric dynamic therapy (PEDT). The asymmetric photothermal effect of the Janus NPs creates thermophoretic force to propel NP motion, which enhances tumor diffusion and cellular uptake of NPs and boosts cytotoxicity and intracellular ROS levels. The inoculation of Au NPs increases the photothermal effect, exhibits larger motion velocities, produces higher pyroelectric potentials, and elevates cellular uptake rates, resulting in significant induction of tumor cell apoptosis, suppression of tumor growth, and extension of animal survival. Thus, the concise design of tBT@PDA-Au/NIR treatment has achieved thermophoretic motion-promoted tissue diffusion, built-in electric field-enhanced cell internalization, and photothermal/PEDT-synergized antitumor efficacy.

A gold nanoparticle engineered metal-organic framework nanoreactor for combined ferroptosis and mild photothermal therapy

We demonstrate a gold nanoparticle engineered metal-organic framework nanoreactor with photothermal, glucose oxidase-like and GSH-consuming performance to achieve the accumulation of hydroxyl radicals and the enhancement of the thermal sensitivity for combined ferroptosis and mild photothermal therapy.

Sialic acid-targeting multi-functionalized silicon quantum dots for synergistic photodynamic and photothermal cancer therapy

To explore the potential of silicon quantum dots (SiQDs) in combined photodynamic therapy (PDT) and photothermal therapy (PTT), we engineered the surface of SiQDs with the photosensitizer Ce6 and the tumor-cell-targeting ligand phenylboronic acid (PBA) via polydopamine-mediated chemistry. Upon irradiation with light of specific wavelengths, SiQDs@Ce6/PBA could generate high levels of reactive oxygen species (ROS) and trigger effective photo-to-thermal conversion. PBA-conjugation could not only increase the cellular uptake and transcellular transport capability of nanoparticles, but also enhance their tumor accumulation. In the presence of a 635 nm laser, SiQDs@Ce6/PBA was able to trigger intracellular ROS production, which further altered the mitochondrial membrane potential and promoted apoptosis of tumor cells. Finally, combined PDT/PTT treatments led to synergistically enhanced cancer cell killing and tumor-growth inhibition effects. This study demonstrates the surface engineering of silicon quantum dots for synergistic PDT/PTT cancer therapy.

Pt nanozyme-bridged covalent organic framework-aptamer nanoplatform for tumor targeted self-strengthening photocatalytic therapy

Covalent organic frameworks (COFs) have emerged as a promising platform for nanomedicine, while developing multifunctional COF nanoplatforms remains challenging due to the lack of efficient strategies for COF modification. Herein, we propose a nanozyme bridging (NZB) strategy for COF functionalization. Platinum nanoparticles (Pt NPs) as catalase mimics were in situ grown on the surface of COF NPs without reducing their drug loading capacity (CP), and thiol-terminated aptamer was further densely decorated onto CP NPs via a stable Pt-S bond (CPA). Pt nanozyme engineering and aptamer functionalization rendered the nanoplatform with excellent photothermal conversion, tumor targeting, and catalase-like catalytic performances. Using clinical-approved photosensitizer indocyanine green (ICG) as a model drug, we fabricated a nanosystem (ICPA) for tumor-targeted self-strengthening therapy. ICPA can effectively accumulate into tumor tissue and relieve the hypoxia microenvironment by decomposing the overexpressed H₂O₂ and generating O₂. Under monowavelength NIR light irradiation, the catalase-like catalytic and singlet oxygen generation activities of ICPA can be significantly strengthened, leading to admirable photocatalytic treatment effects against malignant cells as well as tumor-bearing mice in a self-strengthening manner.

Multifunctional gold nanorods in low-temperature photothermal interactions for combined tumor starvation and RNA interference therapy

Collateral damage to healthy tissue, uneven heat distribution, inflammatory diseases, and tumor metastasis induction hinder the translation of high-temperature photothermal therapy (PTT) from bench to practical clinical applications. In this report, a multifunctional gold nanorod (GNR)-based nanosystem was designed by attaching siRNA against B7-H3 (B7-H3si), glucose oxidase (GOx), and hyaluronic acid (HA) for efficient low-temperature PTT. Herein, GOx can not only exhaust glucose to induce starvation therapy but also reduce the heat shock protein (HSP), realizing the ablation of tumors without damage to healthy tissues. Evidence shows that B7-H3, a type I transmembrane glycoprotein molecule, plays essential roles in growth, metastasis, and drug resistance. By initiating the downregulation of B7-H3 by siRNA, siRNA-GOx/GNR@HA NPs may promote the effectiveness of treatment. By targeting cluster of differentiation 44 (CD44) and depleting B7-H3 and HSPs sequentially, siRNA-GOx/GNR@HA NPs showed 12.9-fold higher lung distribution than siRNA-GOx/GNR NPs. Furthermore, 50% of A549-bearing mice in the siRNA-GOx/GNR NPs group survived over 50 days. Overall, this low-temperature phototherapeutic nanosystem provides an appropriate strategy for eliminating cancer with high treatment effectiveness and minimal systemic toxicity. STATEMENT OF SIGNIFICANCE: To realize efficient tumor ablation under mild low-temperature (42-45 ℃) and RNA interference simultaneously, here we developed a multifunctional gold nanorod (GNR)-based nanosystem (siRNA-GOx/GNR@HA NPs). This nanoplatform can significantly inhibit tumor cell proliferation and induce cell apoptosis by downregulation of HSP90α, HSP70, B7-H3, p-AKT, and p-ERK and upregulation of cleaved caspase-9 at mild low-temperature due to its superior tumor homing ability and the combined effect of photothermal effect, glucose deprivation-initiated tumor starvation, and B7-H3 gene silence effect. It is believed that this multifunctional low-temperature photothermal nanosystem with efficient and specific anticancer properties, shows a potential application in clinical tumor treatment.

Liquid exfoliation of ultrasmall zirconium carbide nanodots as a noninflammatory photothermal agent in the treatment of glioma

Photothermal therapy (PTT), like other clinical translational tumor ablation techniques, requires a temperature increase above 50 °C to cause necrosis and death of tumor cells. Although the tumor can be eliminated rapidly by PTT, the inflammatory response is triggered by the large amounts of released reactive oxygen species (ROS). Therefore, liquid exfoliation was used to create ultrasmall zirconium carbide nanodots (NDs) with an average diameter of approximately 4.5 nm as noninflammatory/anti-inflammatory photosensitizers for PTT of glioma. Ultrasmall ZrC NDs showed excellent photothermal stability and biocompatibility but no obvious toxicity. Moreover, the ultrasmall ZrC NDs effectively ablated glioma at relatively low concentrations and inhibited tumor migration and proliferation in vitro and in vivo. Furthermore, the excellent ROS-scavenging ability of ultrasmall ZrC NDs suppressed the inflammatory response to PTT. Intriguingly, we found that ZrC had the capability of performing CT imaging. We demonstrated that the ultrasmall ZrC NDs created in this study could effectively and safely treat glioma without inflammation.

Multifunctional theragnostic ultrasmall gold nanodot-encapsuled perfluorocarbon nanodroplets for laser-focused ultrasound sequence irradiation (LFSI)-based enhanced tumor ablation

Despite the substantial potential of focused ultrasound therapy, its efficacy in cancer therapy has been limited due to the high cavitation threshold and safety concerns regarding the use of high-intensity energy pulses. Here, ultrasmall Au nanodot-loaded PEG-modified perfluorocarbon nanodroplets (Au-PFCnDs) were prepared and used as a therapeutic enhancer. A LFSI method was designed to achieve enhanced tumor ablation at a mild focused ultrasound (FUS) energy pulse with the assistance of the instinct photothermal effect of intratumor-permeable ultrasmall Au nanodots under 808 nm NIR laser irradiation. In addition to their therapeutic function, Au-PFCnDs can also generate multimodal images to provide information for tumor surveillance and treatment guidance. The experimental results also showed that the cRGD-targeted Au-PFCnDs could be more efficiently delivered into the tumor and selectively destroy tumors with no observable side effects on normal tissue under LFSI treatment.

Nanoparticles-based phototherapy systems for cancer treatment: Current status and clinical potential

Remarkable progress in phototherapy has been made in recent decades, due to its non-invasiveness and instant therapeutic efficacy. In addition, with the rapid development of nanoscience and nanotechnology, phototherapy systems based on nanoparticles or nanocomposites also evolved as an emerging hotspot in nanomedicine research, especially in cancer. In this review, first we briefly introduce the history of phototherapy, and the mechanisms of phototherapy in cancer treatment. Then, we summarize the representative development over the past three to five years in nanoparticle-based phototherapy and highlight the design of the innovative nanoparticles thereof. Finally, we discuss the feasibility and the potential of the nanoparticle-based phototherapy systems in clinical anticancer therapeutic applications, aiming to predict future research directions in this field. Our review is a tutorial work, aiming at providing useful insights to researchers in the field of nanotechnology, nanoscience and cancer.

Nanozyme-laden intelligent macrophage EXPRESS amplifying cancer photothermal-starvation therapy by responsive stimulation

Precise delivery and responsive activation of therapeutic agents are critical for tumor precise therapy. Herein, inspired by intelligent express, a nanozyme-laden intelligent macrophage express was fabricated based on IR 820-macrophage loaded with GOx nanozymes for tumor-targeted photothermal-amplified starvation therapy with fluorescence imaging guidance. The nanozyme-laden intelligent macrophage express exerted precise delivery through cargo loading, conveying and unloading. For efficient cargo loading, H₂O₂-sensitive GOx nanozymes with blocked enzymatic activity were packaged on macrophage expresses with excellent phagocytic ability. Due to the inherent tumor tropism, the therapeutic agents-laden macrophage expresses naturally accumulated at tumor site with fluorescence navigation to track the conveying process. The spatiotemporal unpacking of the laden therapeutic agents at tumor site was triggered by the external laser for the macrophage express photothermal property. The released special tumor-microenvironment responsive GOx nanozymes were activated by H₂O₂ in tumor to start starvation therapy. Photothermal therapy generated mild hyperthermia and starvation therapy produced H₂O₂ further increased the nanozymes enzymatic activity, enhancing GOx-mediated starvation therapy. The nanozyme-laden intelligent macrophage express integrated laser-induce drug release and activation, tumor microenvironment-responsiveness, and circular amplification property, achieving the synergistic effects of PTT and starvation therapy in vitro and in vivo.

Near-Infrared-II Activatable Symbiotic 2D Carbon-Clay Nanohybrids for Dual Imaging-Guided Combinational Cancer Therapy

Two-dimensional (2D) nanomaterials hold great potential for cancer theranostic applications, yet their clinical translation faces great challenges of high toxicity and limited therapeutic/diagnostic modality. Here, we have created a kind of symbiotic 2D carbon-2D clay nanohybrids, which are composed of a novel 2D carbon nanomaterial (carbon nanochips, or CNC), prepared by carbonizing a conjugated polymer polydiiodobutadiyne, and a 2D layered aluminosilicate clay mineral montmorillonite (MMT). Intriguingly, with the formation of the nanohybrids, MMT can help the dispersion of CNC, while CNC can significantly reduce the hemolysis and toxicity of MMT. The symbiotic combination of CNC and MMT also leads to a synergistic anti-cancer theranostic effect. CNC has a strong absorption and high photothermal conversion efficiency in the second near-infrared region (NIR-II, 1000-1700 nm), while MMT contains Fe3+ that can facilitate the generation of reactive oxygen species from highly expressed H2O2 in tumor microenvironment. The nanohybrids not only enable a synergy of photothermal therapy and chemodynamic therapy to suppress the extremely rapid growth of RM1 tumors in mice but also allow for dual photoacoustic and magnetic imaging to guide the drug delivery and NIR-II irradiation execution, hence establishing a highly efficient and biosafe "all-in-one" theranostic platform for precision nanomedicine.

Fluorous-Tagged Peptide Nanoparticles Ameliorate Acute Lung Injury via Lysosomal Stabilization and Inflammation Inhibition in Pulmonary Macrophages

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common respiratory critical syndrome that currently has no effective therapeutic interventions. Pulmonary macrophages play a principal role in the initiation and progression of the overwhelming inflammation in ALI/ARDS. Here, a type of fluorous-tagged bioactive peptide nanoparticle termed CFF13F is developed, which can be efficiently internalized by macrophages and suppress the excessive expression of cytokines and the overproduction of reactive oxygen species (ROS) triggered by lipopolysaccharide (LPS). The cytoprotective effect of CFF13F may be attributed to the lysosomal-stabilization property and regulation of the antioxidative system. Moreover, intratracheal pretreatment with CFF13F can effectively reduce local and systematic inflammation, and ameliorate pulmonary damage in an LPS-induced ALI murine model. The therapeutic efficacy of CFF13F is affected by the administration routes, and the local intratracheal injection is found to be the optimal choice for ALI treatment, with preferred biodistribution profiles. The present study provides solid evidence of the potent immunomodulatory bioactivity of the fluorous-tagged peptide nanoparticles CFF13F in vitro and in vivo, and sheds light on the development of novel efficient nanodrugs for ALI/ARDS.

pH-Responsive Au@Pd bimetallic core-shell nanorods for enhanced synergistic targeted photothermal-augmented nanocatalytic therapy in the second near-infrared window

Nanotheranostic agents based on plasmonic nanostructures with their resonance wavelengths located in the second near-infrared window (NIR-II) have gained significant attention in profound tumor photothermal therapy. However, the modulation of localized surface plasmon resonance of gold nanomaterials from the first near-infrared (NIR-I) window to the NIR-II window is still challenging. The structures and compositions of the plasmonic nanomaterials have demonstrated promising characteristics in controlling the optical properties of plasmonic nanostructures. Here, gold nanorod (Au NR) coated with an ultrathin palladium (Pd) shell was developed for tumor-targeted NIR-II photothermal-augmented nanocatalytic therapy through the combination of compositional manipulation and structural evolution strategies. These Au@Pd core-shell hybrid NRs (HNRs) were functionalized with biocompatible chitosan (CS) to acquire lower toxicity and higher stability in physiological systems. Further, Au@Pd-CS HNRs were endowed with an excellent targeting ability by conjugating with folic acid (FA). The as-synthesized Au@Pd-CS-FA HNRs show efficient and complete photothermal ablation of tumor cells upon 1064 nm laser irradiation. The remarkable photothermal conversion efficiency of 69.0% was achieved, which is superior to many reported photothermal agents activated in the NIR-II region. Excitingly, Au@Pd-CS-FA HNRs have peroxidase and catalase activities, simultaneously producing ˙OH for catalytic therapy and O₂ for relieving tumor hypoxia and photodynamic therapy. Additionally, in vivo tumor photothermal therapy was carried out, where the biocompatible Au@Pd-CS-FA HNRs penetrate intensely into the tumor cells and consequently show remarkable therapeutic effects. The idea about plasmonic modulation behind the bimetallic core-shell nanostructure in this report can be extended to construct new classes of metal-based nanotheranostic agents with dual-modal combined therapy as an alternative to traditional chemotherapy.

Research Progress of Conjugated Nanomedicine for Cancer Treatment

The conventional cancer therapeutic modalities include surgery, chemotherapy and radiotherapy. Although immunotherapy and targeted therapy are also widely used in cancer treatment, chemotherapy remains the cornerstone of tumor treatment. With the rapid development of nanotechnology, nanomedicine is believed to be an emerging field to further improve the efficacy of chemotherapy. Until now, there are more than 17 kinds of nanomedicine for cancer therapy approved globally. Thereinto, conjugated nanomedicine, as an important type of nanomedicine, can not only possess the targeted delivery of chemotherapeutics with great precision but also achieve controlled drug release to avoid adverse effects. Meanwhile, conjugated nanomedicine provides the platform for combining several different therapeutic approaches (chemotherapy, photothermal therapy, photodynamic therapy, thermodynamic therapy, immunotherapy, etc.) with the purpose of achieving synergistic effects during cancer treatment. Therefore, this review focuses on conjugated nanomedicine and its various applications in synergistic chemotherapy. Additionally, the further perspectives and challenges of the conjugated nanomedicine are also addressed, which clarifies the design direction of a new generation of conjugated nanomedicine and facilitates the translation of them from the bench to the bedside.

Aptamer-Functionalized Iron-Based Metal–Organic Frameworks (MOFs) for Synergistic Cascade Cancer Chemotherapy and Chemodynamic Therapy

Hypoxia-activated prodrugs (HAPs) with selective toxicity in tumor hypoxic microenvironments are a new strategy for tumor treatment with fewer side effects. Nonetheless, the deficiency of tumor tissue enrichment and tumor hypoxia greatly affect the therapeutic effect of HAPs. Herein, we design an active targeted drug delivery system driven by AS1411 aptamer to improve the tumor tissue enrichment of HAPs. The drug delivery system, called TPZ@Apt-MOF (TA-MOF), uses iron-based MOF as a carrier, surface-modified nucleolin aptamer AS1411, and the internal loaded hypoxia activation prodrug TPZ. Compared with naked MOF, the AS1411-modified MOF showed a better tumor targeting effect both in vitro and in vivo. MOF is driven by GSH to degrade within the tumor, producing Fe2+, and releasing the cargo. This process leads to a high consumption of the tumor protective agent GSH. Then, the Fenton reaction mediated by Fe2+ not only consumes the intracellular oxygen but also increases the intracellular production of highly toxic superoxide anions. This enhances the toxicity and therapeutic effect of TPZ. This study provides a new therapeutic strategy for cancer treatment.

Reversing tumor multidrug resistance with a catalytically active covalent organic framework

We report here a catalytically active nano covalent organic framework [COF(Fe)] with high drug loading capacity for reversing tumor multidrug resistance (MDR). The Fe catalytic sites in COF(Fe) could convert intracellular overexpressed H₂O₂ into highly reactive ˙OH to induce oxidation stress and down-regulate MDR protein. Therefore, COF(Fe) could enhance the intracellular drug accumulation to overcome MDR, which was demonstrated both in vitro and in vivo.

Multicolor Covalent Organic Framework-DNA Nanoprobe for Fluorescence Imaging of Biomarkers with Different Locations in Living Cells

Precisely detecting biomarkers in living systems holds tremendous promise for disease diagnosis and monitoring. Herein, we developed a covalent organic framework (COF)-based tricolor fluorescent nanoprobe for simultaneously imaging biomarkers with different spatial locations in living cells. Briefly, a TAMRA-labeled survivin mRNA antisense nucleotide and a Cy5-labeled transmembrane glycoprotein mucin 1 (MUC1) aptamer were adsorbed on a nanoscale fluorescent COF. To enhance the interactions between COF nanoparticles (NPs) and nucleic acid molecules, a freezing method was employed for improving the nucleic acid loading density and ensuring detection performance. The fluorescence signals of dyes on DNAs were first quenched by the COF NPs. Internalization and distribution of the nanoprobes can be real-time visualized by the autofluorescence of COF NPs. In living cells, recognition between MUC1 with MUC1 aptamers causes fluorescence signal recovery of Cy5, while hybridization between survivin mRNA and its antisense DNA induces the signal recovery of TAMRA. Therefore, this COF-based multicolor nanoprobe could be employed for visualizing MUC1 on the cell membrane and survivin mRNA in the cytoplasm. Cancer cell-specific diagnostic imaging and monitoring of the process of cancer cell exosomes infecting normal cells using the nanoprobe were achieved. This work not only offers a versatile nanoprobe for bioanalysis but also provides new insights for developing novel COF-based nanoprobes.