Black SnO2-x based nanotheranostic for imaging-guided photodynamic/photothermal synergistic therapy in the second near-infrared window

An Asymmetric NIR-II Organic Fluorophore with an Ultra-Large Stokes Shift for Imaging-Guided and Targeted Phototherapy

NIR-II imaging-guided phototherapy is an attractive, yet challenging, tumor treatment strategy. By monitoring the accumulation of phototherapy reagents at the tumor site through imaging and determining the appropriate therapy window, the therapeutic effect could be significantly improved. Probes with NIR-II (1000-1700 nm) fluorescence emission and a large Stokes shift hold great promise for fluorescence imaging with deep penetration, minimized self-quenching, and high spatiotemporal resolution. However, due to the lack of a suitable molecular framework, the design of a simple small-molecule dye with a large Stokes shift and NIR-II fluorescence emission has rarely been reported. Herein, we prepare an asymmetric D-π-A type NIR-II fluorescence probe (TBy). The probe is incapsulated in an amphiphilic polymer and modified with a fibronectin targeting peptide CREKA, which could recognize the fibrin-fibronectin complex overexpressed in multiple malignant tumors. The nanoparticles thus constructed (TByC-NPs) have maximum fluorescence emission at 1037 nm with a large Stokes shift of 426 nm, which is the largest Stokes shift among organic NIR-II fluorescent dyes reported in the literature. The TByC-NPs exhibit a good NIR-II imaging performance, active tumor targeting, and good photothermal and photodynamic capabilities. In vitro and in vivo studies verify that the TByC nanoplatform shows outstanding biocompatibility for NIR-II imaging-guided phototherapy and provides an excellent antitumor effect.

Iron/Molybdenum Sulfide Nanozyme Cocatalytic Fenton Reaction for Photothermal/Chemodynamic Efficient Wound Healing

The issue of bacterial infectious diseases remains a significant concern worldwide, particularly due to the misuse of antibiotics, which has caused the emergence of antibiotic-resistant strains. Fortunately, the rapid development of nanomaterials has propelled significant progress in antimicrobial therapy, offering promising solutions. Among them, the utilization of nanoenzyme-based chemodynamic therapy (CDT) has become a highly hopeful approach to combating bacterial infectious diseases. Nevertheless, the application of CDT appears to be facing certain constraints for its low efficiency in the Fenton reaction at the infected site. In this study, we have successfully synthesized a versatile nanozyme, which was a composite of molybdenum sulfide (MoS2) and iron sulfide (FeS2), through the hydrothermal method. The results showed that iron/molybdenum sulfide nanozymes (Fe/Mo SNZs) with desirable peroxidase (POD) mimic activity can generate cytotoxic reactive oxygen species (ROS) by successfully triggering the Fenton reaction. The presence of MoS2 significantly accelerates the conversion of Fe2+/Fe3+ through a cocatalytic reaction that involves the participation of redox pairs of Mo4+/Mo6+, thereby enhancing the efficiency of CDT. Additionally, based on the excellent photothermal performance of Fe/Mo SNZs, a near-infrared (NIR) laser was used to induce localized temperature elevation for photothermal therapy (PTT) and enhance the POD-like nanoenzymatic activity. Notably, both in vitro and in vivo results demonstrated that Fe/Mo SNZs with good broad-spectrum antibacterial properties can help eradicate Gram-negative bacteria like Escherichia coli and Gram-positive bacteria like Staphylococcus aureus. The most exciting thing is that the synergistic PTT/CDT exhibited astonishing antibacterial ability and can achieve complete elimination of bacteria, which promoted wound healing after infection. Overall, this study presents a synergistic PTT/CDT strategy to address antibiotic resistance, providing avenues and directions for enhancing the efficacy of wound healing treatments and offering promising prospects for further clinical use in the near future.

Size transformable organic nanotheranostic agents for NIR-II imaging-guided oncotherapy

Nanotheranostic agents combined the second near-infrared (NIR-II, 1000-1700 nm) fluorescence imaging with phototherapy strategy have attracted tremendous interest. However, the actual efficacy of NIR-II probes could be weakened by their limited accumulation and penetration in tumor tissues. Herein, a size-transformable NIR-II nanotheranostic agent (BBT-HASS@FPMPL NPs) is employed for simultaneously enhanced penetration and retention in deep tumor tissue to realize precise image and effective PTT therapy. BBT-HASS@FPMPL NPs were first formed by using hyaluronic acid (HA) chains and disulfide bonds as stimuli-responsive "lock" to efficiently load conjugated oligomer (BBTN+), and then folic acid (FA) modified polylysine (FPMPL) shell was stacked at the surface by electrostatic interaction. Dual targeting with HA and FA is expected to lead to more selective targeting and better accumulation of BBT-HASS@FPMPL NPs in tumor sites. Simultaneously, obvious particle size reduction and charge reversal can be triggered in acidic tumor microenvironment to achieve deep intratumor filtration through transcytosis. Following tumor penetration, size change was further initiated by overexpressed hyaluronidase and GSH in tumor. Free BBTN+ can be subsequently released from nanoparticles to promote specific intratumor retention, which synergistically enhance photothermal therapeutic efficacy. Owing to sufficient tumor accumulation and deep penetration, the NIR-II emission of BBTN+ could further be used for precise monitoring of subcutaneous tumor progression in mice for 6 days with just one dose injection. We expect that such nanotheranostic platform that combined the high resolution of NIR-II fluorescence with deep tumor penetration and long intratumor retention could be useful for real-time monitoring of tumor process, precise diagnosis, and enhanced phototherapy.

Near-Infrared-II-Activatable Self-Assembled Manganese Porphyrin-Gold Heterostructures for Photoacoustic Imaging-Guided Sonodynamic-Augmented Photothermal/Photodynamic Therapy

Porphyrins and their derivatives are widely used as photosensitizers and sonosensitizers in tumor treatment. Nevertheless, their poor water solubility and low chemical stability reduce their singlet oxygen (1O2) yield and, consequently, their photodynamic therapy (PDT) and sonodynamic therapy (SDT) efficiency. Although strategies for porphyrin molecule assembly have been developed to augment 1O2 generation, there is scope for further improving PDT and SDT efficiencies. Herein, we synthesized ordered manganese porphyrin (SM) nanoparticles with well-defined self-assembled metalloporphyrin networks that enabled efficient energy transfer for enhanced photocatalytic and sonocatalytic activity in 1O2 production. Subsequently, Au nanoparticles were grown in situ on the SM surface by anchoring the terminal alkynyl of porphyrin to form plasmonic SMA heterostructures, which showed the excellent near-infrared-II (NIR-II) region absorption and photothermal properties, and facilitated electron-hole pair separation and transfer. With the modification of hyaluronic acid (HA), SMAH heterostructure nanocomposites exhibited good water solubility and were actively targeted to cancer cells. Under NIR-II light and ultrasound (US) irradiation, the SMAH generates hyperthermia, and a large amount of 1O2, inducing cancer cell damage. Both in vitro and in vivo studies confirmed that the SMAH nanocomposites effectively suppressed tumor growth by decreasing GSH levels in SDT-augmented PDT/PTT. Moreover, by utilizing the strong absorption in the NIR-II window, SMAH nanocomposites can achieve NIR-II photoacoustic imaging-guided combined cancer treatment. This work provides a paradigm for enhancing the 1O2 yield of metalloporphyrins to improve the synergistic therapeutic effect of SDT/PDT/PTT.

Application of hyaluronic acid-based nanoparticles for cancer combination therapy

Cancer is a significant public health problem in the world. The treatment methods include surgery, chemotherapy, phototherapy, and immunotherapy. Due to their respective limitations, the treatment effect is often unsatisfactory, laying hidden dangers for metastasis and recurrence. Since their exceptional biocompatibility and excellent targeting capabilities, hyaluronic acid-based biomaterials have generated great interest as drug delivery methods for tumor therapy. Moreover, modified HA can self-assemble into hydrogels or nanoparticles (NPs) for precise drug administration. This article summarizes the application of HA-based NPs in combination therapy. Ultimately, it is anticipated that this research will offer guidance for creating various HA-based NPs utilized in numerous cancer therapies.

Oxygen-Deficient Bioceramics: Combination of Diagnosis, Therapy, and Regeneration

The journey of ceramics in medicine has been synchronized with an evolution from the first generation-alumina, zirconia, etc.-to the third -3D scaffolds. There is an up-and-coming member called oxygen-deficient or colored bioceramics, which have recently found their way through biomedical applications. The oxygen vacancy steers the light absorption toward visible and near infrared regions, making the colored bioceramics multifunctional-therapeutic, diagnostic, and regenerative. Oxygen-deficient bioceramics are capable of turning light into heat and reactive oxygen species for photothermal and photodynamic therapies, respectively, and concomitantly yield infrared and photoacoustic images. Different types of oxygen-deficient bioceramics have been recently developed through various synthesis routes. Some of them like TiO2- x , MoO3- x , and WOx have been more investigated for biomedical applications, whereas the rest have yet to be scrutinized. The most prominent advantage of these bioceramics over the other biomaterials is their multifunctionality endowed with a change in the microstructure. There are some challenges ahead of this category discussed at the end of the present review. By shedding light on this recently born bioceramics subcategory, it is believed that the field will undergo a big step further as these platforms are naturally multifunctional.

Phototoxicity of Tridentate Ru(II) Polypyridyl Complex with Expanded Bite Angles toward Mammalian Cells and Multicellular Tumor Spheroids

Tridentate ligand-coordinated ruthenium (II) polypyridyl complexes with large N-Ru-N bite angles have been shown to promote ligand field splitting and reduce singlet-triplet state mixing leading to dramatically extended emission quantum yields and lifetimes under ambient conditions. These effects are anticipated to enhance their photoinduced singlet oxygen production, promoting prospects for such complexes as type II phototherapeutics. In this contribution, we examined this putative effect for [Ru(bqp)(bqpCOOEt)]2+, Ru-bqp-ester, a heteroleptic complex containing bqp = [2,6-bi(quinolin-8-yl)pyridine], a well-established large bite angle tridentate ligand, as well as its peptide conjugates [Ru(bqp)(bqpCONH-ahx-FrFKFrFK(Ac)-CONH2)]5+ (Ru-bqp-MPP) and [Ru(bqp) (bqp)(CONH-ahx-RRRRRRRR-CONH2)]10+ (Ru-bqp-R8) that were prepared in an effort to promote live cell/tissue permeability and targeting of the parent. Membrane permeability of both parent and peptide conjugates were compared across 2D cell monolayers; A549, Chinese hamster ovary, human pancreatic cancer (HPAC), and 3D HPAC multicellular tumor spheroids (MCTS) using confocal microscopy. Both the parent complex and peptide conjugates showed exceptional permeability with rapid uptake in both 2D and 3D cell models but with little distinction in permeability or distribution in cells between the parent or peptide conjugates. Unexpectedly, the uptake was temperature independent and so attributed to passive permeation. Both dark and photo-toxicity of the Ru(II) complexes were assessed across cell types, and the parent showed notably low dark toxicity. In contrast, the parent and conjugates were found to be highly phototoxic, with impressive phototoxic indices (PIs) toward HPAC cell monolayers in particular, with PI values ranging from ∼580 to 760. Overall, our data indicate that the Ru(II) parent complex and its peptide conjugates show promise at both cell monolayers and 3D MCTS as photosensitizers for photodynamic therapy.

Near-infrared-II-activatable sulfur-deficient plasmonic Bi2S3-x-Au heterostructures for photoacoustic imaging-guided ultrasound enhanced high performance phototherapy

Bismuth sulfide is widely used as an n-type semiconductor material in photocatalytic reactions. However, bismuth sulfide has poor absorption in the near-infrared region and low charge separation efficiency, limiting its application in phototherapy and sonodynamic therapy (SDT). In this study, we successfully synthesized an "all-in-one" phototheranostic nanoplatform, namely Bi₂S_3-x-Au@HA, based on a single second near-infrared (NIR-II) light-responsive Schottky-type Bi₂S_3-x-Au heterostructure for photoacoustic (PA) imaging-guided SDT-enhanced photodynamic therapy (PDT)/photothermal therapy (PTT). Bi₂S_3-x-Au@HA exhibits excellent NIR-II plasmonic and photothermal properties, rendering it with NIR-II PA imaging capabilities for accurate diagnosis. Additionally, the high-density sulfur vacancies constructed on the Bi₂S₃ surface cause it to possess a reduced band gap (1.21 eV) that can act as an electron trap. Using the density functional theory, we confirmed that the light and ultrasound-induced electrons are more likely to aggregate on the Au nanoparticle surface through interfacial self-assembly, which promotes electron-hole separation and enhances photocatalytic activity with increased reactive oxygen species (ROS) generation. With a further modification of hyaluronic acid (HA), Bi₂S_3-x-Au@HA can selectively target cancer cells through HA and CD44 protein interactions. Both in vitro and in vivo experiments demonstrated that Bi₂S_3-x-Au@HA effectively suppressed tumor growth through SDT-enhanced PTT/PDT under a single NIR-II laser and ultrasound irradiation with negligible toxicity. Our findings provide a framework for fabricating Schottky-type heterostructures as single NIR-II light-responsive nanotheranostic agents for PA imaging-guided cancer phototherapy.

Near-infrared band responsive ROS regulator selectively inhibits breast cancer cells by programming combination phototherapy

Catalytic therapy can effectively kill tumor cells and inhibit tumor growth by producing highly toxic reactive oxygen species (ROS). However, the long-term catalysis of nanozymes easily lead to ROS breaking through the boundary in tumor tissues, resulting in spillover and injuring normal cells. Therefore, how to control the threshold of ROS production from nanozymes in tumor tissues is an unsolved problem. In this work, to prevent the boundary effect of the photosensitizer ([Ru(bpy)2(tip)]²⁺, RBT) during ROS generation, we used the sensitivity of RBT and PdH_0.2-Ir with different wavelengths of near-infrared light (NIR) to generate ROS and H₂, respectively. Therefore, an intelligent nanosystem PdH_0.2-Ir@RBT(PIH@R) was constructed to precisely control ROS generation by adjusting the NIR laser wavelength. The palladium-iridium alloy (Pd-Ir) nanoparticles as the core can co-load hydrogen (H₂) and RBT and show NIR-responsive behaviors. Under 808 nm laser irradiation, PIH@R produces ROS with the photocatalysis of RBT, while under 1064 nm laser irradiation PIH@R will quickly activate and release H₂ to eliminate ROS. Interestingly, in vitro and in vivo experiments showed that PIH@R acted like a "Trojan horse": PIH@R can destroy the mitochondria of 4T1 cells to destroy their redox homeostasis system, resulting in cancer cells relying on exogenous PIH@R to change their reactive oxygen species levels. Subsequently, when PIH@R is activated into a harmful oxidation state, it can easily crush the redox homeostasis system of cancer cells and induce cancer cell apoptosis.

Advances in Single-component inorganic nanostructures for photoacoustic imaging guided photothermal therapy

Phototheranostic based on photothermal therapy (PTT) and photoacoustic imaging (PAI), as one of avant-garde medical techniques, have sparked growing attention because it allows noninvasive, deeply penetrative, and highly selective and effective therapy. Among a variety of phototheranostic nanoagents, single-component inorganic nanostructures are found to be novel and attractive PAI and PTT combined nanotheranostic agents and received tremendous attention, which not only exhibit structural controllability, high tunability in physiochemical properties, size-dependent optical properties, high reproducibility, simple composition, easy functionalization, and simple synthesis process, but also can be endowed with multiple therapeutic and imaging functions, realizing the superior therapy result along with bringing less foreign materials into body, reducing systemic side effects and improving the bioavailability. In this review, according to their synthetic components, conventional single-component inorganic nanostructures are divided into metallic nanostructures, metal dichalcogenides, metal oxides, carbon based nanostructures, upconversion nanoparticles (UCNPs), metal organic frameworks (MOFs), MXenes, graphdiyne and other nanostructures. On the basis of this category, their detailed applications in PAI guide PTT of tumor treatment are systematically reviewed, including synthesis strategies, corresponding performances, and cancer diagnosis and therapeutic efficacy. Before these, the factors to influence on photothermal effect and the principle of in vivo PAI are briefly presented. Finally, we also comprehensively and thoroughly discussed the limitation, potential barriers, future perspectives for research and clinical translation of this single-component inorganic nanoagent in biomedical therapeutics.

Progress of Nanomaterials in Photodynamic Therapy Against Tumor

Photodynamic therapy (PDT) is an advanced therapeutic strategy with light-triggered, minimally invasive, high spatiotemporal selective and low systemic toxicity properties, which has been widely used in the clinical treatment of many solid tumors in recent years. Any strategies that improve the three elements of PDT (light, oxygen, and photosensitizers) can improve the efficacy of PDT. However, traditional PDT is confronted some challenges of poor solubility of photosensitizers and tumor suppressive microenvironment. To overcome the related obstacles of PDT, various strategies have been investigated in terms of improving photosensitizers (PSs) delivery, penetration of excitation light sources, and hypoxic tumor microenvironment. In addition, compared with a single treatment mode, the synergistic treatment of multiple treatment modalities such as photothermal therapy, chemotherapy, and radiation therapy can improve the efficacy of PDT. This review summarizes recent advances in nanomaterials, including metal nanoparticles, liposomes, hydrogels and polymers, to enhance the efficiency of PDT against malignant tumor.

Nanomaterials-based photosensitizers and delivery systems for photodynamic cancer therapy

The increasing cancer morbidity and mortality requires the development of high-efficiency and low-toxicity anticancer approaches. In recent years, photodynamic therapy (PDT) has attracted much attention in cancer therapy due to its non-invasive features and low side effects. Photosensitizer (PS) is one of the key factors of PDT, and its successful delivery largely determines the outcome of PDT. Although a few PS molecules have been approved for clinical use, PDT is still limited by the low stability and poor tumor targeting capacity of PSs. Various nanomaterial systems have shown great potentials in improving PDT, such as metal nanoparticles, graphene-based nanomaterials, liposomes, ROS-sensitive nanocarriers and supramolecular nanomaterials. The small molecular PSs can be loaded in functional nanomaterials to enhance the PS stability and tumor targeted delivery, and some functionalized nanomaterials themselves can be directly used as PSs. Herein, we aim to provide a comprehensive understanding of PDT, and summarize the recent progress of nanomaterials-based PSs and delivery systems in anticancer PDT. In addition, the concerns of nanomaterials-based PDT including low tumor targeting capacity, limited light penetration, hypoxia and nonspecific protein corona formation are discussed. The possible solutions to these concerns are also discussed.

Extended π-Conjugative Carbon Nitride for Single 1064 nm Laser-Activated Photodynamic/Photothermal Synergistic Therapy and Photoacoustic Imaging

The synergetic photodynamic/photothermal therapy, activated via a single-second near-infrared (NIR-II) laser and guided by photoacoustic imaging (PAI), receives significant attention for precise in vivo therapy. However, due to the lack of a corresponding theranostic agent, it faces a great challenge for practical clinical implementation. Here, we present a single diagnostic and therapeutic nanoplatform named carbon nitride nanoparticles (CN-NPs) for efficient NIR-II PAI-guided photodynamic therapy (PDT)/photothermal therapy (PTT). The CN-NPs were obtained by incorporating an aromatic compound (PTCDA) with a large π-structure into melem by high-temperature polymerization. The absorption of the obtained CN-NPs was significantly enhanced compared with pristine melem. Under 1064 nm laser illumination, sufficient reactive oxygen species (ROS) generated by CN-NPs could reduce the mitochondrial membrane potential. Moreover, the CN-NPs exhibited an efficient PTT effect through improved photothermal stability and high photo-to-heat conversion efficiency (47.6%). We were also able to monitor the accumulation and metabolism of CN-NPs in vivo of mice in real time using PAI. The in vivo experiments proved that the CN-NPs could inhibit tumor growth and recurrence completely under 1064 nm. Thus, the proposed innovative strategy would open a new avenue to explore and construct NIR-II responsive nanoplatforms with enhanced performance and safety for multimodal phototheranostics.