Advances of Photothermal Agents with Fluorescence Imaging/Enhancement Ability in the Field of Photothermal Therapy and Diagnosis

Development of a Highly Efficient NIR-II Phototherapeutic Agent for Fluorescence Imaging-Guided Synergistic PTT/PDT/Chemotherapy of Colorectal Cancer

NIR-II-triggered phototherapy presents a noninvasive, resistance-free alternative therapeutic approach with deeper tissue penetration and improved imaging of deep tumors. However, many NIR-II phototherapeutic agents suffer from low fluorescence quantum yields, poor photothermal conversion efficiency (PCE), and reduced efficacy due to the upregulation of heat shock protein HSP70. This study develops a small-molecule NIR-II phototherapeutic agent (IRF) with a high fluorescence quantum yield (17.4%), excellent PCE (96.8%) for photothermal therapy (PTT), and photodynamic therapy (PDT) activity. To decrease thermal resistance during phototherapy, IRF and evodiamine (EVO) were loaded onto hyaluronic acid (HA)-modified nanoparticles, creating a multifunctional nanoplatform termed EVO/IRF@HA NPs. EVO/IRF@HA NPs can actively target tumors for NIR-II fluorescence imaging via the HA moiety. Upon 980 nm laser irradiation, IRF increases the temperature and content of reactive oxygen species for synergistic PTT/PDT. Importantly, EVO effectively inhibits the overexpression of HSP70, enabling combined PTT/PDT/chemotherapy for effective colorectal cancer (CRC) treatment.

Ultrasound-Driven Nitric Oxide Generation for Enhanced Sonodynamic-Photothermal Therapy

Recently, green gas therapy based on nitric oxide (NO) has gained considerable attention in cancer treatment. The supplementation of exogenous NO and its controlled release represent promising strategies for adjuvant tumor therapy. In this study, we developed a novel ultrasound (US)-triggered NO generation and release nanoplatform that integrates NO therapy, sonodynamic therapy, and photothermal therapy (PTT) into a collaborative therapeutic modality. An environmentally friendly biomacromolecule, polydopamine, was employed to coload chlorin e6 (Ce6) and NO donor (BNN6), resulting in the nanocomposite PDA-Ce6/BNN6 (PCB). A single US stimulus simultaneously activated Ce6 to produce reactive oxygen species (ROS) and promoted BNN6 to release NO. The dual effects of ultrasonic mechanical action and physiological modulation by NO substantially improved local vascular function and enhanced tumor cell permeability, thereby increasing the targeted accumulation of PCB within tumors. Reactive nitrogen species (RNS) derived from NO and ROS further exacerbated oxidative damage and enhanced the sensitivity of tumor cells to hyperthermia. Both in vitro and in vivo experiments demonstrated that ultrasonic stimulation of NO/ROS/RNS combined with PTT effectively inhibited tumor cell growth and proliferation. The findings suggest that NO gas therapy based on extracorporeal US can significantly amplify the efficacy of PTT and offer new insights for developing other combined strategies aimed at physically regulating deep tumors.

Metal-Polyphenol Self-Assembled Nanophotothermal Agent for Precise Mitochondrial Targeted Photothermal Therapy

Nanocarriers have been extensively utilized to improve the stability of photothermal agents in vivo, enhance delivery efficiency, and reduce drug side effects. However, challenges, such as the low safety of carrier materials, insufficient loading of therapeutic agents, and complex preparation procedures, still persist. In this study, the photothermal agent IR780 was encapsulated in network TA-Fe3+ (TF) which was self-assembled by tannic acid (TA) and Fe3+ to synthesize an acid-responsive multifunctional nanophotothermal agent TF@IR780 (TR). In the slightly acidic tumor microenvironment (TME), network shell TF is degraded, and the internal photothermal agent IR780 is exposed. On the one hand, the TF network can improve the solubility and stability of photothermal agent IR780 in vivo and significantly increase the uptake efficiency in tumor cells. On the other hand, Fe3+ exhibits magnetic resonance imaging (MRI) functionality, which combined with the fluorescence imaging of IR780 endows TR with multimodal imaging capabilities. In addition, TR is easy to release photosensitizers through acid response in the low pH environment of TME, and achieves precise damage to mitochondria through mitochondrial anchoring and light regulation. This overcomes the drawbacks of traditional tumor treatment methods, such as poor specificity, and demonstrates efficient and controllable antitumor activity.

Injectable, Biodegradable and Photothermal Hydrogel with Quorum Sensing Inhibitory Effects for Subcutaneous Fungal Infection Treatment

Owing to the high invasion depth and easy formation of biofilms, the treatment of subcutaneous fungal infection is intractable and challenging. Herein, we report an injectable and biodegradable hydrogel with bactericidal, quorum sensing inhibition and antioxidant activities for the in situ treatment of subcutaneous fungal infection. The hydrogel (BEPE) was constructed by irradiating mixed bovine serum albumin (BSA), ε-polylysine and epigallocatechin gallate (EGCG)-loaded mesoporous polydopamine (PDA) under near-infrared (NIR) light. BEPE exerted microbicidal effects against Candida albicans (99.5%) and Streptococcus mutans (99.6%) through synergistic photothermal effects and the microbiocidal activity of slowly released ε-polylysine. Moreover, the gently released EGCG from BEPE with relatively high bioavailability, synergistically inhibited and destroyed biofilms by inhibiting quorum sensing between microbes, resulting in an antibiofilm efficiency of 80.5% against C. albicans. An in vivo subcutaneous fungal infection study revealed that BEPE accelerates tissue regeneration via targeted formation, elimination of fungal infection and alleviation of inflammation in situ, thereby promoting wound healing. This biodegradable hydrogel strategy will facilitate the design of multifunctional microbicidal agents for targeted subcutaneous fungal infection treatment.

MOF-derived intelligent arenobufagin nanocomposites with glucose metabolism inhibition for enhanced bioenergetic therapy and integrated photothermal-chemodynamic-chemotherapy

Bioenergetic therapy based on tumor glucose metabolism is emerging as a promising therapeutic modality. To overcome the poor bioavailability and toxicity of arenobufagin (ArBu), a MOF-derived intelligent nanosystem, ZIAMH, was designed to facilitate energy deprivation by simultaneous interventions of glycolysis, OXPHOS and TCA cycle. Herein, zeolitic imidazolate framework-8 was loaded with ArBu and indocyanine green, encapsulated within metal-phenolic networks for chemodynamic therapy and hyaluronic acid modification for tumor targeting. ZIAMH nanoparticles can release ArBu in the tumor microenvironment for chemtherapy, and ICG enables photothermal therapy under near-infrared laser irradiation. In vitro and in vivo mechanism studies revealed that the ZIAMH nanoplatform downregulated glucose metabolism related genes, resulting in the reduction of energy substances and metabolites in tumors. Additionally, it significantly promoted cell apoptosis by upregulating pro-apoptotic proteins such as Bax, Bax/Bcl-2, cytochrome C. Animal studies have shown that the tumor inhibition efficiency of ZIAMH nanomedicines was three fold higher than that of free drugs. Therefore, this study provides a new strategy for glucose metabolism-mediated bioenergetic therapy and PTT/CDT/CT combined therapy for tumors.

Photodynamic Therapy Synergizes CD47 Blockade Strategy for Enhanced Antitumor Therapy

The antitumor strategies based on innate immunity activation have become favored by researchers in recent years. In particular, strategies targeting antiphagocytic signaling blockade to enhance phagocytosis have been widely reported. For example, the addition of prophagocytic signals such as calreticulin could make the strategy significantly more effective. In this study, an antitumor strategy that combines photodynamic therapy (PDT) with CD47 blockade has been reported. This approach promotes the maturation of dendritic cells and the presentation of tumor antigens by PDT-mediated tumor immunogenic cell death, as well as the enhancement of cytotoxic T lymphocyte infiltration in tumor areas and the phagocytic activity of phagocytes. Furthermore, the downregulation and blockage of CD47 protein could further promote phagocytic activity, strengthen the innate immune system, and ultimately elevate the antitumor efficacy and inhibit tumor metastasis.

Self-Delivery Nanoplatform Based on Amphiphilic Apoptosis Peptide for Precise Mitochondria-Targeting Photothermal Therapy

Mitochondria-targeting photothermal therapy could significantly enhance the tumor cell killing effect. However, since therapeutic reagents need to overcome a series of physiological obstacles to arrive at mitochondria accurately, precise mitochondria-targeting photothermal therapy still faces great challenges. In this study, we developed a self-delivery nanoplatform that specifically targeted the mitochondria of tumor cells for precise photothermal therapy. Photothermal agent IR780 was encapsulated by amphiphilic apoptotic peptide KLA with mitochondria-targeting ability to form nanomicelle KI by self-assembly through hydrophilic and hydrophobic interactions. Subsequently, negatively charged tumor-targeting polymer HA was coated on the surface of KI through electrostatic interactions, to obtain tumor mitochondria-targeting self-delivery nanoplatform HKI. Through CD44 receptor-mediated recognition, HKI was internalizated by tumor cells and then disassembled in an acidic environment with hyaluronidase in endosomes, resulting in the release of apoptotic peptide KLA and photothermal agent IR780 with mitochondria anchoring capacity, which achieved precise mitochondria guidance and destruction. This tumor mitochondria-targeting self-delivery nanoplatform was able to effectively deliver photothermal agents and apoptotic peptides to tumor cell mitochondria, resulting in precise destruction to mitochondria and enhancing tumor cell inhibition at the subcellular organelle level.