Terrylenediimide-Based Intrinsic Theranostic Nanomedicines with High Photothermal Conversion Efficiency for Photoacoustic Imaging-Guided Cancer Therapy

A perylene diimide probe for NIR-II fluorescence imaging guided photothermal and type I/type II photodynamic synergistic therapy

Phototherapy has garnered significant attention in the past decade. Photothermal and photodynamic synergistic therapy combined with NIR fluorescence imaging has been one of the most attractive treatment options because of the deep tissue penetration, high selectivity and excellent therapeutic effect. Benefiting from the superb photometrics and ease of modification, perylene diimide (PDI) and its derivatives have been employed as sensing probes and therapeutic agents in the biological and biomedical research fields, and exhibiting excellent potential. Herein, we reported the development of a novel organic small-molecule phototherapeutic agent, PDI-TN. The absorption of PDI-TN extends into the NIR region, which provides feasibility for NIR phototherapy. PDI-TN overcomes the traditional Aggregation-Caused Quenching (ACQ) effect and exhibits typical characteristics of Aggregation-Induced Emission (AIE). Subsequently, PDI-TN NPs were obtained by using an amphiphilic triblock copolymer F127 to encapsulate PDI-TN. Interestingly, the PDI-TN NPs not only exhibit satisfactory photothermal effects, but also can generate O2•- and 1O2 through type I and type II pathways, respectively. Additionally, the PDI-TN NPs emit strong fluorescence in the NIR-II region, and show outstanding therapeutic potential for in vivo NIR-II fluorescence imaging. To our knowledge, PDI-TN is the first PDI derivative used for NIR-II fluorescence imaging-guided photodynamic and photothermal synergistic therapy, which suggests excellent potential for future biological/biomedical applications.

A Novel Multi-Effect Photosensitizer for Tumor Destruction via Multimodal Imaging Guided Synergistic Cancer Phototherapy

Background

How to ingeniously design multi-effect photosensitizers (PSs), including multimodal imaging and multi-channel therapy, is of great significance for highly spatiotemporal controllable precise phototherapy of malignant tumors.

Methods

Herein, a novel multifunctional zinc(II) phthalocyanine-based planar micromolecule amphiphile (ZnPc 1) was successfully designed and synthesized, in which N atom with photoinduced electron transfer effect was introduced to enhance the near-infrared absorbance and nonradiative heat generation. After simple self-assembling into nanoparticles (NPs), ZnPc 1 NPs would exhibit enhanced multimodal imaging properties including fluorescence (FL) imaging (FLI) /photoacoustic (PA) imaging (PAI) /infrared (IR) thermal imaging, which was further used to guide the combined photodynamic therapy (PDT) and photothermal therapy (PTT).

Results

It was that under the self-guidance of the multimodal imaging, ZnPc 1 NPs could precisely pinpoint the tumor from the vertical and horizontal boundaries achieving highly efficient and accurate treatment of cancer.

Conclusion

Accordingly, the integration of FL/PA/IR multimodal imaging and PDT/PTT synergistic therapy pathway into one ZnPc 1 could provide a blueprint for the next generation of phototherapy, which offered a new paradigm for the integration of diagnosis and treatment in tumor and a promising prospect for precise cancer therapy.

Activable Nano-Immunomodulator Assembled from π-Extended Naphthalenediimide for Precision Photothermal Immunotherapy

A nano-immunomodulator (R-NPT NP) comprising a tumor microenvironment (TME) activable resiquimod (R848) and a π-extended NIR-absorbing naphthophenanthrolinetetraone (NPT) has been engineered for spatiotemporal controlled photothermal immunotherapy. R-NPT NP demonstrated excellent photostability, while R848 promoted synergistic immunity as a toll-like receptor 7/8 (TLR7/8) agonist. Upon accumulation at the tumor site, R-NPT NP released R848 in response to redox metabolite glutathione (GSH), triggering dendritic cell (DC) activation. The photothermal effect endowed by R-NPT NP can ablate tumors directly and trigger immunogenic cell death to augment immunity after photoirradiation. The synergistic effect of GSH-liable TLR7/8 agonist and released immunogenic factors leads to a robust evocation of systematic immunity through promoted DC maturation and T cell infiltration. Thus, R-NPT NP with photoirradiation achieved 99.3 % and 98.2 % growth inhibition against primary and distal tumors, respectively.

Aggregation-enhanced photothermal therapy of organic dyes

Photothermal therapy (PTT) represents a groundbreaking approach to targeted disease treatment by harnessing the conversion of light into heat. The efficacy of PTT heavily relies on the capabilities of photothermal agents (PTAs). Among PTAs, those based on organic dyes exhibit notable characteristics such as adjustable light absorption wavelengths, high extinction coefficients, and high compatibility in biological systems. However, a challenge associated with organic dye-based PTAs lies in their efficiency in converting light into heat while maintaining stability. Manipulating dye aggregation is a key aspect in modulating non-radiative decay pathways, aiming to augment heat generation. This review delves into various strategies aimed at improving photothermal performance through constructing aggregation. These strategies including protecting dyes from photodegradation, inhibiting non-photothermal pathways, maintaining space within molecular aggregates, and introducing intermolecular photophysical processes. Overall, this review highlights the precision-driven assembly of organic dyes as a promising frontier in enhancing PTT-related applications. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Gallic acid-loaded HFZIF-8 for tumor-targeted delivery and thermal-catalytic therapy

"Transition" metal-coordinated plant polyphenols are a type of promising antitumor nanodrugs owing to their high biosafety and catalytic therapy potency; however, the major obstacle restricting their clinical application is their poor tumor accumulation. Herein, Fe-doped ZIF-8 was tailored using tannic acid (TA) into a hollow mesoporous nanocarrier for gallic acid (GA) loading. After hyaluronic acid (HA) modification, the developed nanosystem of HFZIF-8/GA@HA was used for the targeted delivery of Fe ions and GA, thereby intratumorally achieving the synthesis of an Fe-GA coordinated complex. The TA-etching strategy facilitated the development of a cavitary structure and abundant coordination sites of ZIF-8, thus ensuring an ideal loading efficacy of GA (23.4 wt%). When HFZIF-8/GA@HA accumulates in the tumor microenvironment (TME), the framework is broken due to the competitive protonation ability of overexpressed protons in the TME. Interestingly, the intratumoral degradation of HFZIF-8/GA@HA provides the opportunity for the in situ "meeting" of GA and Fe ions, and through the coordination of polyhydroxyls assisted by conjugated electrons on the benzene ring, highly stable Fe-GA nanochelates are formed. Significantly, owing to the electron delocalization effect of GA, intratumorally coordinated Fe-GA could efficiently absorb second near-infrared (NIR-II, 1064 nm) laser irradiation and transfer it into thermal energy with a conversion efficiency of 36.7%. The photothermal performance could speed up the Fenton reaction rate of Fe-GA with endogenous H2O2 for generating more hydroxyl radicals, thus realizing thermally enhanced chemodynamic therapy. Overall, our research findings demonstrate that HFZIF-8/GA@HA has potential as a safe and efficient anticancer nanodrug.

Deciphering Oxygen-Independent Augmented Photodynamic Oncotherapy by Facilitating the Separation of Electron-Hole Pairs

Developing Type-I photosensitizers provides an attractive approach to solve the dilemma of inadequate efficacy of photodynamic therapy (PDT) caused by the inherent oxygen consumption of traditional Type-II PDT and anoxic tumor microenvironment. The challenge for the exploration of Type-I PSs is to facilitate the electron transfer ability of photosensitization molecules for transforming oxygen or H2O to reactive oxygen species (ROS). Herein, we propose an electronic acceptor-triggered photoinduced electron transfer (a-PET) strategy promoting the separation of electron-hole pairs by marriage of two organic semiconducting molecules of a non-fullerene scaffold-based photosensitizer and a perylene diimide that significantly boost the Type-I PDT pathway to produce plentiful ROS, especially, inducing 3.5-fold and 2.5-fold amplification of hydroxyl (OH⋅) and superoxide (O2 -⋅) generation. Systematic mechanism exploration reveals that intermolecular electron transfer and intramolecular charge separation after photoirradiation generate a competent production of radical ion pairs that promote the Type-I PDT process by theoretical calculation and ultrafast femtosecond transient absorption (fs-TA) spectroscopy. By complementary tumor diagnosis with photoacoustic imaging and second near-infrared fluorescence imaging, this as-prepared nanoplatform exhibits fabulous photocytotoxicity in harsh hypoxic conditions and terrific cancer revoked abilities in living mice. We envision that this work will broaden the insight into high-efficiency Type-I PDT for cancer phototheranostics.

Perylene-Mediated Cytoskeletal Dysfunction Remodels Cancer-Associated Fibroblasts to Augment Antitumor Immunotherapy

Targeted reprogramming of cancer-associated fibroblasts (CAFs) is one of the most essential cancer therapies. However, how to reprogram active CAFs toward deactivated state still remains immense challenge. To tackle this challenge, herein, one perylene N, N'-bis(2-((dimethylammonium)ethylene)-2-(methoxylethyl))-1, 6, 7, 12-tetrachloroperylene-3, 4, 9, 10-tetracarboxylic diimide (PDIC-OC) is prepared, which can trigger endogenous reactive oxygen species (ROS) burst to result in cytoskeletal dysfunction and cell apoptosis so that suppress transforming growth factor β (TGF-β) production. As a result, PDIC-OC can reprogram the activated CAFs and relieve immunosuppressive tumor microenvironment by efficient polarization of M2-typed macrophages into M1-typed ones, downregulation of alpha-smooth muscle actin (α-SMA), alleviation of hypoxic state to promote infiltration of cytotoxic T lymphocytes, and ultimately realizes outstanding antitumor performance on B16F10 tumor-xenografted and lung-metastatic mouse model even at low concentration of 1 mg kg-1 body weight. This work thus presents a novel strategy that cytoskeleton dysfunction and cell apoptosis cooperatively suppress the secretion of TGF-β to reprogram CAFs and meanwhile clarifies intrinsic mechanism for perylene-triggered chemo-immunotherapy against hypoxic tumors.

Nanoparticles as carriers of photosensitizers to improve photodynamic therapy in cancer

Photodynamic therapy (PDT) has emerged as a promising non invasive therapeutic approach for cancer treatment, offering unique advantages over conventional treatments. The combination of light activation and photosensitizing agents allows for targeted and localized destruction of cancer cells, reducing damage to surrounding healthy tissues. In recent years, the integration of nanoparticles with PDT has garnered significant attention due to their potential to enhance therapeutic outcomes. This review article aims to provide a comprehensive overview of the current state-of-the-art in utilizing nanoparticles for photodynamic therapy in cancer treatment. We summarized various nanoparticle-based approaches, their properties, and their implications in optimizing PDT efficacy, and discussed challenges and prospects in the field.

D-A-D organic fluorescent probes for NIR-II fluorescence imaging and efficient photothermal therapy of breast cancer

Near-infrared second region (NIR-II) fluorescent probes are used in the diagnosis of early cancer due to their high tissue penetration. However, there are still few reports on organic small molecule fluorescent probes with NIR-II fluorescence imaging (NIR-II FI) combined with efficient photothermal therapy (PTT). In this study, planar cyclopentadithiophene (CPDT) was incorporated into the twisted structural skeleton (D-A-D), and the strong acceptor TTQ molecule (A) and the donor triphenylamine (D) were introduced to synthesize an organic small molecule (TCT) with enhanced NIR-II fluorescence emission performance. To improve the hydrophilicity of TCT molecules, we used the nanoprecipitation method to coat DSPE-mPEG2000 on the TCT molecules and obtained nanoparticles (TCT-NPs) with a strong absorption band, good water dispersibility, and NIR-II FI ability, which realized NIR-II FI-guided PTT for breast cancer tumors. Due to their effective near-infrared absorption, TCT-NPs exhibit high photothermal conversion efficiency (η = 40.1%) under 660 nm laser irradiation, making them a photothermal therapeutic agent with good performance. Therefore, TCT-NPs have the potential to diagnose, eliminate, and monitor the diffusion of cancer.

Chiral Bay-Alkynylated Tetraazaperylenes: Photophysics and Chiroptical Properties

Fully bay-alkynylated octaazaperopyrene dioxide (OAPPDO) derivatives were accessible through Stille cross coupling reaction of the corresponding bay-chlorinated derivatives. This steric congestion of the bay area led to helically chiral fluorophores, and chiral resolution of two derivatives allowed the investigation of their chiroptical properties as well as their kinetics of enantiomerization and the related thermodynamic parameters depending on the size of the terminal alkynyl substituent. An increase of the latter resulted in stable OAPPDO atropisomers at room temperature. The dynamics of the photoexcited states of two of the OAPPDO derivatives were investigated by transient absorption (TA) and time-resolved photoluminescence (tr-PL) spectroscopy.

Soluble Nanographene C222: Synthesis and Applications for Synergistic Photodynamic/Photothermal Therapy

Nanographene C222, which consists of a planar graphenic plane containing 222 carbon atoms, holds the record as the largest planar nanographene synthesized to date. However, its complete insolubility makes the processing of C222 difficult. Here we addressed this issue by introducing peripheral substituents perpendicular to the graphene plane, effectively disrupting the interlayer stacking and endowing C222 with good solubility. We also found that the electron-withdrawing substituents played a crucial role in the cyclodehydrogenation process, converting the dendritic polyphenylene precursor to C222. After disrupting the interlayer stacking, the introduction of only a few peripheral carboxylic groups allowed C222 to dissolve in phosphate buffer saline, reaching a concentration of up to 0.5 mg/mL. Taking advantage of the good photosensitizing and photothermal properties of the inner C222 core, the resulting water-soluble C222 emerged as a single-component agent for both photothermal and photodynamic tumor therapy, exhibiting an impressive tumor inhibition rate of 96%.

Size Modulation of Conjugated Polymer Nanoparticles for Improved NIR-II Fluorescence Imaging and Photothermal Therapy

Near-infrared-II fluorescence imaging (NIR-II FI) has become a powerful imaging technique for disease diagnosis owing to its superiorities, including high sensitivity, high spatial resolution, deep imaging depth, and low background interference. Despite the widespread application of conjugated polymer nanoparticles (CPNs) for NIR-II FI, most of the developed CPNs have quite low NIR-II fluorescence quantum yields based on the energy gap law, which makes high-sensitivity and high-resolution imaging toward deep lesions still a huge challenge. This work proposes a nanoengineering strategy to modulate the size of CPNs aimed at optimizing their NIR-II fluorescence performance for improved NIR-II phototheranostics. By adjusting the initial concentration of the synthesized conjugated polymer, a series of CPNs with different particle sizes are successfully prepared via a nanoprecipitation approach. Results show that the NIR-II fluorescence brightness of CPNs gradually amplifies with decreasing particle size, and the optimal CPNs, NP0.2, demonstrate up to a 2.05-fold fluorescence enhancement compared with the counterpart nanoparticles. With the merits of reliable biocompatibility, high photostability, and efficient light-heat conversion, the optimal NP0.2 has been successfully employed for NIR-II FI-guided photothermal therapy both in vitro and in vivo. Our work highlights an effective strategy of nanoengineering to improve the NIR-II performance of CPNs, advancing the development of NIR-II FI in life sciences.

NIR-II photothermal conversion and imaging based on a cocrystal containing twisted components

On account of the scarcity of molecules with a satisfactory second near-infrared (NIR-II) response, the design of high-performance organic NIR photothermal materials has been limited. Herein, we investigate a cocrystal incorporating tetrathiafulvalene (TTF) and tetrachloroperylene dianhydride (TCPDA) components. A stable radical was generated through charge transfer from TTF to TCPDA, which exhibits strong and wide-ranging NIR-II absorption. The metal-free TTF-TCPDA cocrystal in this research shows high photothermal conversion capability under 1064 nm laser irradiation and clear photothermal imaging. The remarkable conversion ability-which is a result of twisted components in the cocrystal-has been demonstrated by analyses of single crystal X-ray diffraction, photoluminescence and femtosecond transient absorption spectroscopy as well as theoretical calculations. We have discovered that space charge separation and the ordered lattice in the TTF-TCPDA cocrystal suppress the radiative decay, while simultaneously strong intermolecular charge transfer enhances the non-radiative decay. The twisted TCPDA component induces rapid charge recombination, while the distorted configuration in TTF-TCPDA favors an internal non-radiative pathway. This research has provided a comprehensive understanding of the photothermal conversion mechanism and opened a new way for the design of advanced organic NIR-II photothermal materials.

Pd8 Nanocluster with Nonmetal-to-Metal- Ring Coordination and Promising Photothermal Conversion Efficiency

Constructing ambient-stable, single-atom-layered metal-based materials with atomic precision and understanding their underlying stability mechanisms are challenging. Here, stable single-atom-layered nanoclusters of Pd were synthesized and precisely characterized through electrospray ionization mass spectrometry and single-crystal X-ray crystallography. A pseudo-pentalene-like Pd8 unit was found in the nanocluster, interacting with two syn PPh units through nonmetal-to-metal -ring coordination. The unexpected coordination, which is distinctly different from the typical organoring-to-metal coordination in half-sandwich-type organometallic compounds, contributes to the ambient stability of the as-obtained single-atom-layered nanocluster as revealed through theoretical and experimental analyses. Furthermore, quantum chemical calculations revealed dominant electron transition along the horizontal x-direction of the Pd8 plane, indicating high photothermal conversion efficiency (PCE) of the nanocluster, which was verified by the experimental PCE of 73.3 %. Therefore, this study unveils the birth of a novel type of compound and the finding of the unusual nonmetal-to-metal -ring coordination and has important implications for future syntheses, structures, properties, and structure-property correlations of single-atom-layered metal-based materials.

Versatile Design of Organic Polymeric Nanoparticles for Photodynamic Therapy of Prostate Cancer

Radical prostatectomy is a primary treatment option for localized prostate cancer (PCa), although high rates of recurrence are commonly observed postsurgery. Photodynamic therapy (PDT) has demonstrated efficacy in treating nonmetastatic localized PCa with a low incidence of adverse events. However, its limited efficacy remains a concern. To address these issues, various organic polymeric nanoparticles (OPNPs) loaded with photosensitizers (PSs) that target prostate cancer have been developed. However, further optimization of the OPNP design is necessary to maximize the effectiveness of PDT and improve its clinical applicability. This Review provides an overview of the design, preparation, methodology, and oncological aspects of OPNP-based PDT for the treatment of PCa.

Croconaine conjugated cationic polymeric nanoparticles for NIR enhanced bacterial killing

Light-triggered treatment approach has been regarded as an effective option for sterilization due to noninvasiveness, limited drug resistance, and minimized adverse effects. Herein, we designed and synthesized a functionalized cationic polymer, CR-PQAC, with croconaine bridging agent and quaternary ammonium groups for photothermal enhanced antimicrobial therapy under near-infrared irradiation. The quaternary ammonium group on the pendent chain endowing CR-PQAC the ability to effectively bind to bacteria. The CR-PQAC could self-assembles into micellar nanoparticles in aqueous solution, which exhibited strong absorption in the near-infrared (NIR) region, excellent photostability, and photothermal conversion efficiency of up to 43.8 %. Notably, the CR-PQAC nanoparticles presented remarkable antibacterial activity against both methicillin-resistant Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria with 808 nm laser irradiation. Moreover, the developed CR-PQAC has negligible dark cytotoxicity and good hemolytic compatibility against mammalian cells. Both in vitro and in vivo studies have demonstrated that the desirable antibacterial efficacy of CR-PQAC was obtained. Therefore, the proposed CR-PQAC may be a promising antimicrobial agent for NIR-enhanced killing bacterial.

Biomedical Application of Porphyrin-Based Amphiphiles and Their Self-Assembled Nanomaterials

Porphyrins have been vastly explored and applied in many cutting-edge fields with plenty of encouraging achievements because of their excellent properties. As important derivatives of porphyrins, porphyrin-based amphiphiles (PBAs) not only maintain the advanced properties of porphyrins (catalysis, imaging, and energy transfer) but also possess self-assembly and encapsulation capability in aqueous solution. Accordingly, PBAs and their self-assembles have had important roles in diagnosing and treating tumors and inflammation lesions in vivo, but not limited to these. In this article, we introduce the research progress of PBAs, including their constitution, structure design strategies, and performances in tumor and inflammation lesion diagnosis and treatments. On that basis, the defects of synthesized PBAs during their application and the possible effective strategies to overcome the limitations are also proposed. Finally, perspectives on PBAs exploration are updated based on our knowledge. We hope this review will bring researchers from various domains insights about PBAs.

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.

Facile Photoresponsive Actuators Based on Ferrocene-Doped Poly(butyl methacrylate)

This paper presents facile photoresponsive actuators comprising ferrocene as a guest chromophore and poly(butyl methacrylate) (PBMA) as a host matrix. The ferrocene-doped PBMA film exhibits mechanical expansion and contraction when a 445 nm laser is turned on and off, respectively. The photoresponsive film is attached by a commercially available acetylcellulose adhesive tape, which exhibits a bending motion that is controlled by turning the laser on and off. Thereafter, the double-layer film is employed to fabricate a table-shaped lifting machine (0.7 mg) that lifts a 10.5 mg object up and down by turning the laser on and off, respectively, and the mechanical force offered by the double-layer film is recorded. Additionally, the film is coated with gold and applied to an electric circuit that serves as a reversible photoresponsive switch. This film preparation technique is applied to other chromophores (e.g., Coumarin 343, Rhodamine 6G, Sudan Blue II, and Solvent Green 3) to independently control the motions of the films with 445, 520, and 655 nm lasers. The ferrocene-containing films also exhibit photoinduced healing from mechanical damage. Finally, the photoirradiation-accompanied morphological changes in the film are observed via small-angle X-ray scattering.

Precise Planar-Twisted Molecular Engineering to Construct Semiconducting Polymers with Balanced Absorption and Quantum Yield for Efficient Phototheranostics

Semiconducting polymers (SPs) have shown great feasibility as candidates for near-infrared-II (NIR-II) fluorescence imaging-navigated photothermal therapy due to their strong light-harvesting ability and flexible tunability. However, the fluorescence signal of traditional SPs tends to quench in their aggregate states owing to the strong π-π stacking, which can lead to the radiative decay pathway shutting down. To address this issue, aggregation-induced emission effect has been used as a rational tactic to boost the aggregate-state fluorescence of NIR-II emitters. In this contribution, we developed a precise molecular engineering tactic based on the block copolymerizations that integrate planar and twisted segments into one conjugated polymer backbone, providing great flexibility in tuning the photophysical properties and photothermal conversion capacity of SPs. Two monomers featured with twisted and planar architectures, respectively, were tactfully incorporated via a ternary copolymerization approach to produce a series of new SPs. The optimal copolymer (SP2) synchronously shows desirable absorption ability and good NIR-II quantum yield on the premise of maintaining typical aggregation-induced emission characteristics, resulting in balanced NIR-II fluorescence brightness and photothermal property. Water-dispersible nanoparticles fabricated from the optimal SP2 show efficient photothermal therapeutic effects both in vitro and in vivo. The in vivo investigation reveals the distinguished NIR-II fluorescence imaging performance of SP2 nanoparticles and their photothermal ablation toward tumor with prominent tumor accumulation ability and excellent biocompatibility.

NIR-II Perylene Monoimide-Based Photothermal Agent with Strengthened Donor-Acceptor Conjugation for Deep Orthotopic Glioblastoma Phototheranostics

Extensive efforts have been devoted to the design of organic photothermal agents (PTAs) that absorb in the second near-infrared (NIR-II) bio-window, which can provide deeper tissue penetration that is significant for phototheranostics of lethal brain tumors. Herein, the first example of NIR-II-absorbing small organic molecule (N1) derived from perylene monoamide (PMI) and its bio-application after nano-encapsulation of N1 to function as a nano-agent for phototheranostics of deep orthotopic glioblastoma (GBM) is reported. By adopting a dual modification strategy of introducing a donor-acceptor unit and extending π-conjugation, the obtained N1 can absorb in 1000-1400 nm region and exhibit high photothermal conversation due to the apparent intramolecular charge transfer (ICT). A choline analogue, 2-methacryloyloxyethyl phosphorylcholine, capable of interacting specifically with receptors on the surface of the blood-brain barrier (BBB), is used to fabricate the amphiphilic copolymer for the nano-encapsulation of N1. The obtained nanoparticles demonstrate efficient BBB-crossing due to the receptor-mediated transcytosis as well as the small nanoparticle size of approximately 26 nm. The prepared nanoparticles exhibit excellent photoacoustic imaging and significant growth inhibition of deep orthotopic GBM. The current study demonstrates the enormous potential of PMI-based NIR-II PTAs and provides an efficient phototheranostic paradigm for deep orthotopic GBM.

Nanostructured organic photosensitizer aggregates in disease phototheranostics

Aggregate science provides promising opportunities for the discovery of novel disease phototheranostics. Under the guidance of aggregology and the Jablonski energy level diagram, photosensitizer aggregates with tunable photophysical properties can consequently result in tailorable diagnosis and treatment modalities. This review summarizes recent advances in the formation of nanostructured organic photosensitizer aggregates, their photophysical processes (e.g., radiative emission, vibrational relaxation, and intersystem crossing), and particularly, their applications in disease phototheranostics such as fluorescence imaging and sensing, photothermal therapy, photoacoustic imaging, and photodynamic therapy. It is expected that this comprehensive summary will provide guidance for the construction of nanostructured organic photosensitizer aggregates, for establishment of aggregation-photophysical property relationships and the development of novel disease phototheranostic nanomedicines. Teaser: This article reviews the electron-delocalized π system-caused formation of nanostructured organic photosensitizer aggregates, which undergo radiative emission, vibrational relaxation, or intersystem crossing pathways to achieve fluorescence imaging and sensing, photothermal therapy, photoacoustic imaging, and photodynamic therapy.

Recent Advances in Hydrogel-Based Phototherapy for Tumor Treatment

Phototherapeutic agent-based phototherapies activated by light have proven to be safe modalities for the treatment of various malignant tumor indications. The two main modalities of phototherapies include photothermal therapy, which causes localized thermal damage to target lesions, and photodynamic therapy, which causes localized chemical damage by generated reactive oxygen species (ROS). Conventional phototherapies suffer a major shortcoming in their clinical application due to their phototoxicity, which primarily arises from the uncontrolled distribution of phototherapeutic agents in vivo. For successful antitumor phototherapy, it is essential to ensure the generation of heat or ROS specifically occurs at the tumor site. To minimize the reverse side effects of phototherapy while improving its therapeutic performance, extensive research has focused on developing hydrogel-based phototherapy for tumor treatment. The utilization of hydrogels as drug carriers allows for the sustained delivery of phototherapeutic agents to tumor sites, thereby limiting their adverse effects. Herein, we summarize the recent advancements in the design of hydrogels for antitumor phototherapy, offer a comprehensive overview of the latest advances in hydrogel-based phototherapy and its combination with other therapeutic modalities for tumor treatment, and discuss the current clinical status of hydrogel-based antitumor phototherapy.

Manipulating Host-Guest Charge Transfer of a Water-Soluble Double-Cavity Cyclophane for NIR-II Photothermal Therapy

Water-soluble small organic photothermal agents (PTAs) over NIR-II biowindow (1000-1350 nm) are highly desirable, but the rarity greatly limits their applications. Based on a water-soluble double-cavity cyclophane GBox-4⁴⁺ , we report a class of host-guest charge transfer (CT) complexes as structurally uniform PTAs for NIR-II photothermal therapy. As a result of its high electron-deficiency, GBox-4⁴⁺ can bind different electron-rich planar guests with a 1 : 2 host/guest stoichiometry to readily tune the CT absorption band that extends to the NIR-II region. When using a diaminofluorene guest substituted with an oligoethylene glycol chain, the host-guest system realized both good biocompatibility and enhanced photothermal conversion at 1064 nm, and was then exploited as a high-efficiency NIR-II PTA for cancer cell and bacterial ablation. This work broadens the potential applications of host-guest cyclophane systems and provides a new access to bio-friendly NIR-II photoabsorbers with well-defined structures.

Tumor microenvironment-activated multi-functional nanodrug with size-enlargement for enhanced cancer phototheranostics

Phototheranostics that integrate diagnosis and treatment modalities have shown great promise in personalized cancer therapy. However, the "always on" characteristics often lead to suboptimal imaging quality and severe side effects. Herein, we report the construction of a perylenemonoimide based nanodrug CPMI NP with multi-functional activatable theranostic capability. The nanodrug is facilely co-assembled from a prodrug CPMI and DSPE-mPEG2000. In a tumor microenvironment (TME) with excessive glutathione (GSH), CPMI undergoes a cascade reaction to generate the phototheranostic molecule NPMI and the chemodrug chlorambucil, simultaneously switching on the near-infrared (NIR) fluorescence, photothermal effect, and drug release. The photothermal conversion efficiency is as high as 52.2%. Moreover, NPMI exhibits an enhanced intermolecular π-π stacking effect, leading to significant size-enlargement of the nanodrug and prolonged tumor retention. Due to TME-activation, the strong in vivo fluorescence signal of the tumor can be observed 144 h post injection with a high signal-to-noise ratio of up to 17. The enhanced tumor inhibition efficiency of the nanodrug is confirmed through activatable chemo-photothermal therapy. This work paves the way for the design of activatable phototheranostic agents for accurate cancer diagnosis and treatment.

Rational design of pH-activated upconversion luminescent nanoprobes for bioimaging of tumor acidic microenvironment and the enhancement of photothermal therapy

The development of effective and safe tumor photothermal therapeutic strategies has attracted considerable attention. Herein, we synthesized tumor microenvironment (TME)-activatable self-assembling organic nanotheranostics (NRhD-PEG-X NPs (X = 1, 2, 3, and 4)) for precise tumor targeting and upconversion image-guided photothermal therapy (PTT). The amphiphilic polymer NRhD-PEG-X consisted of upconversion luminescent probes (NRhD) modified with polyethylene glycol (PEG) of various lengths. The continuous external irradiation-free photothermal NRhD-PEG-4 NPs with pKa 6.70 displayed high sensitivity and selectivity to protons, resulting in the turn-on upconversion luminescence and enhanced photothermal properties in the acidic TME without asynchronous therapy and side effects. This nanotheranostic offers acidic activatability, tumor targetability, and PTT enhancement, thus allowing autofluorescence-free upconversion luminescent imaging-guided precision PTT. Our strategy affords a paradigm to develop activatable theranostic nanoplatforms for precision medicine. STATEMENT OF SIGNIFICANCE: As a hyperthermia-based treatment, activatable photothermal therapy (PTT) is highly significant in tumor treatment. Herein, we develop acidic tumor microenvironment-activatable nanotheranostics for upconversion luminescent imaging-guided diagnosis and precision tumor-targeted PTT. PEGylation of upconversion dyes not only could self-assemble to yield organic nanoparticles in water, but it could also significantly improve biocompatibility, stability, and circulation time and tune significantly the pKa value of nanoparticles. In an acidic tumor microenvironment, NRhD-PEG-4 NPs with pKa 6.70 show high sensitivity to release NRhDH⁺-PEG-4 NPs, which exhibit good upconversion luminescence and enhanced photothermal effect. Therefore, upconversion luminescence imaging-guided precision PTT has high potential to enhance cancer diagnostic and therapeutic efficiency.

Biomedical Photoacoustic Imaging for Molecular Detection and Disease Diagnosis: "Always-On" and "Turn-On" Probes

Photoacoustic (PA) imaging is a nonionizing, noninvasive imaging technique that combines optical and ultrasonic imaging modalities to provide images with excellent contrast, spatial resolution, and penetration depth. Exogenous PA contrast agents are created to increase the sensitivity and specificity of PA imaging and to offer diagnostic information for illnesses. The existing PA contrast agents are categorized into two groups in this review: "always-on" and "turn-on," based on their ability to be triggered by target molecules. The present state of these probes, their merits and limitations, and their future development, is explored.

Indocyanine green conjugated phototheranostic nanoparticle for photodiagnosis and photodynamic reaciton

BACKGROUND

Phototheranostics represents a highly promising paradigm for cancer therapy, although selecting an appropriate optical imager and sensitizer for clinical use remains challenging.

METHODS

Liposomally formulated phospholipid-conjugated indocyanine green, denoted as LP-iDOPE, was developed as phototheranostic nanoparticle and its cancer imaging-mediated photodynamic reaction, defined as the immune response induced by photodynamic and photothermal effects, was evaluated with a near-infrared (NIR)-light emitting diode (LED) light irradiator.

RESULTS

Using in vivo NIR fluorescence imaging, we demonstrated that LP-iDOPE was selectively delivered to tumor sites with high accumulation and a long half-life. Following low-intensity NIR-LED light irradiation on the tumor region of LP-iDOPE accumulated, effector CD8⁺ T cells were activated at the secondary lymphoid organs, migrated, and subsequently released cytokines including interferon-γ and tumor necrosis factor-α, resulting in effective tumor regression.

CONCLUSIONS

Our anti-cancer strategy based on tumor-specific LP-iDOPE accumulation and low-intensity NIR-LED light irradiation to the tumor regions, i.e., photodynamic reaction, represents a promising approach to noninvasive cancer therapy.

Boosting Near-Infrared Photothermal Conversion by Intermolecular Interactions in Isomeric Cocrystals

Organic cocrystal exhibits excellent photothermal conversion (PTC), but how the intermolecular interactions of cocrystals regulate the PTC is obscure. Here, two isomeric donor molecules (phenanthrene and anthracene) and two electron-withdrawing molecules (7,7,8,8,8-tetracyanodimethylquinone and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethane) are self-assembled into the four cocrystals (PTQ, PFQ, ATQ, and AFQ). By changing the molecular configuration of the donor and the electron-withdrawing ability of the acceptor, the intrinsic influencing factors of the intermolecular interaction on the PTC were explored. Under near-infrared laser (808 nm) irradiation, the PTC efficiencies of PTQ, PFQ, AFQ, and ATQ are 35.85, 44.74, 57.00, and 60.53%, respectively. Based on the single-crystal X-ray diffraction, ultrafast time-resolved transient absorption, and excited-state theoretical calculations, we found that the π-π stacking in ATQ and AFQ is conducive to promoting the near-infrared light-harvesting ability and the p-π interaction of cocrystals can regulate the nonradiative rotation of -C(C≡N)₂ groups, resulting in a tunable near-infrared PTC via the isomeric cocrystals. Accordingly, the evaporation rate of the porous polyurethane-AFQ foam can reach 1.33 kg·m^-2·h^-1 in the simulated solar-driven water evaporation system. This work provides a strategy to boost the PTC by the intermolecular interactions of cocrystal materials.

Phototherapeutic effect of transformable peptides containing pheophorbide a on colorectal cancer

Photodynamic therapy (PDT) and photothermal therapy (PTT) have attracted research interest for their noninvasive nature and selective treatment of tumor tissues. They are effective through the generation of reactive oxygen species (ROS) or heat. Nevertheless, several problems, including low bioavailability and long-lasting cutaneous photosensitivity, have limited their clinical application. In this study, we reported an in situ self-assembly strategy that could improve various biological properties of the photosensitizer in vivo. A photosensitizer connected to a receptor-mediated smart peptide can self-assemble into nanoparticles (NPs) under the force of hydrophobic interaction and then transform into a nanofibrillar network after attaching to the tumor cell surface with the help of the β-sheet-forming peptide KLVFF. The supramolecular structural changes deeply affected the PDT and PTT properties of the photosensitizer on tumors. After being aggregated into the nanostructure, the water solubility and targeting ability of the photosensitizer was ameliorated. Moreover, the improvement of the photothermal conversion efficiency, ROS generation, and tumor retention followed the formation of nanofibrils (NFs). This self-assembly strategy showed the ability of supramolecular nanofibrils to improve the bioavailability of photosensitizers, which provides a new potential treatment avenue for various cancer therapies.

Azulene-Containing Squaraines for Photoacoustic Imaging and Photothermal Therapy

Photoacoustic imaging (PAI) guided photothermal therapy (PTT) can realize real-time diagnosis and in situ treatment of cancer at the same time. Absorption in the near-infrared (NIR) region with large molar extinction coefficient (ε) and high value of photothermal conversion efficiency (PCE) are key prerequisites for photothermal agents (PTAs) to realize dual PAI and PTT treatments. Squaraines have stable quinoid structures with strong planarity and rigidity, in favor of the NIR absorption and high ε values. On the other hand, azulene derivatives mostly have very faint fluorescence emission, which is beneficial for photothermal transformation. Herein, two azulene-containing squaraines Az-SQ-1 and Az-SQ-2 are synthesized as high-performance PTAs. In comparison with Az-SQ-1, Az-SQ-2 possesses larger ε_max of 3 × 10⁵ M^-1 cm^-1 at 780 nm in organic solution and higher PCE of 53.2% in the form of nanoparticles under 808 nm laser irradiation. Accordingly, Az-SQ-2 NPs present stronger photoacoustic signals (about 15.1-times the background signal) and more efficient suppression of tumor growth. Our research indicates that the introduction of azulene unit to traditional NIR dyes is a simple but effective approach to obtain outstanding PTAs in the aspect of phototheranostics.

Injectable in situ intelligent thermo-responsive hydrogel with glycyrrhetinic acid-conjugated nano graphene oxide for chemo-photothermal therapy of malignant hepatocellular tumor

Malignant tumor is one of the major diseases with high morbidity and mortality. The purpose of this study is to prepare berberine hydrochloride (BH) in situ thermo-sensitive hydrogel based on glycyrrhetinic acid (GA) modified nano graphene oxide (NGO) (GA-BH-NGO-gel). NGO was taken as the photosensitizer, GA was taken as the target molecule, and BH was taken as the model drug. The physicochemical properties and anti-tumor activity in vivo and in vitro were also studied. This subject could provide a certain theoretical basis for the chemo-photothermal therapy combined treatment of malignant tumor. The release behavior of GA-BH-NGO-gel in vitro presented sustained and temperature-dependent drug release effect. The anti-tumor activity studies in vivo and in vitro had shown that GA-BH-NGO-gel had stronger anti-tumor activity, which could be targeting distributed to the tumor tissues. Moreover, the inhibitory effect of GA-BH-NGO-gel was enhanced when combined with 808 nm of laser irradiation. In this research, the chemo-photothermal combination therapy was applied into the tumor treatment, which may provide certain research ideas for the clinical treatment of malignant tumor.

Nanotechnology-based combinatorial phototherapy for enhanced cancer treatment

Nanotechnology-based phototherapy has attracted enormous attention to cancer treatment owning to its non-invasiveness, high controllability and accuracy. Given the fast development of anti-tumor strategies, we summarize various examples of multifunctional nanosystems to highlight the recent advances in nanotechnology-based combinatorial phototherapy towards improving cancer treatment. The limitations of the monotherapeutic approach and the superiority of the photo-involved combinatorial strategies are discussed in each part. The future breakthroughs and clinical perspectives of combinatorial phototherapy are also outlooked. Our perspectives may inspire researchers to develop more effective phototherapy-based cancer-treating approaches.

Ultrasound and nanomaterial: an efficient pair to fight cancer

Ultrasounds are often used in cancer treatment protocols, e.g. to collect tumor tissues in the right location using ultrasound-guided biopsy, to image the region of the tumor using more affordable and easier to use apparatus than MRI and CT, or to ablate tumor tissues using HIFU. The efficacy of these methods can be further improved by combining them with various nano-systems, thus enabling: (i) a better resolution of ultrasound imaging, allowing for example the visualization of angiogenic blood vessels, (ii) the specific tumor targeting of anti-tumor chemotherapeutic drugs or gases attached to or encapsulated in nano-systems and released in a controlled manner in the tumor under ultrasound application, (iii) tumor treatment at tumor site using more moderate heating temperatures than with HIFU. Furthermore, some nano-systems display adjustable sizes, i.e. nanobubbles can grow into micro-bubbles. Such dual size is advantageous since it enables gathering within the same unit the targeting properties of nano bubbles via EPR effect and the enhanced ultrasound contrasting properties of micro bubbles. Interestingly, the way in which nano-systems act against a tumor could in principle also be adjusted by accurately selecting the nano-system among a large choice and by tuning the values of the ultrasound parameters, which can lead, due to their mechanical nature, to specific effects such as cavitation that are usually not observed with purely electromagnetic waves and can potentially help destroying the tumor. This review highlights the clinical potential of these combined treatments that can improve the benefit/risk ratio of current cancer treatments.

Recent Development of MOF-Based Photothermal Agent for Tumor Ablation

Metal-organic frameworks (MOFs) are 3D-architecture compounds of metal ions and organic molecules with sufficient and permanent porosity, showing great potential as a versatile platform to load various functional moieties to endow the hybrid materials with specific applications. Currently, a variety of photothermal nanometals have been embedded into organic ligands for integrating the unique photothermal effects with the merits of MOFs to improve their performances for cancer therapy. In this review, we have summarized a series of novel MOF-based photothermal materials for this unique therapeutic modality against tumors from three main aspects according to their chemical compositions and structures, i) metal-doped MOF, ii) organic-doped MOF, and iii) polymer-coated MOF. In addition, we have summarized the latest developments and characteristics of MOF-based photothermal agents, such as good biocompatibility, low toxicity, and responsive photothermal conversion without destroying the structure of hybrid photothermal agent. At last, we addressed the future perspectives of MOF-based photothermal agent in the field of phototherapy.

Single Probe-Based Chemical-Tongue Sensor Array for Multiple Bacterial Identification and Photothermal Sterilization in Real Time

Simple and efficient identification of multiple bacteria and sterilization in real time is of considerable significance for clinical diagnostics and quality control in food. Herein, a novel chemical-tongue sensor array with 3,3',5,5'-tetramethylbenzidine (TMB) as a single probe was developed for bacterial identification and photothermal elimination. The synthesized bimetallic palladium/platinum nanoparticles (Pd/Pt_NPs) present excellent catalytic capability that can catalyze TMB into oxidized TMB (oxTMB) with four feature absorption peaks. Bacteria have different ability on inhibiting the reaction between TMB and Pd/Pt_NPs. With the absorbance intensity of oxTMB at the four feature peaks as readout, nine kinds of bacteria including two drug-resistant bacteria can be successfully distinguished via linear discriminant analysis. Remarkably, oxTMB exhibits excellent photothermal properties and can effectively kill bacteria in real time under near-infrared laser irradiation. The strategy of selecting TMB as a single probe simplifies the experimental operation and reduces the time cost. Furthermore, the developed sensing system was used to promote the wound healing process of MRSA-infected mice in vivo. The investigation provides a promising simple and efficient strategy for bacterial identification and sterilization with a universal platform, which has great potential application in clinical diagnosis and therapy.

Phthalocyanine-Assembled "One-For-Two" Nanoparticles for Combined Photodynamic-Photothermal Therapy of Multidrug-Resistant Bacteria

The treatment of diseases caused by drug-resistant bacterial infections urgently requires new types of broad-spectrum antimicrobial materials. Herein, we introduce a supramolecular self-assembly, NanoPcN, which realizes the combination of type I photodynamic activity and photothermal effects by modifying zinc(II) phthalocyanine with a 3-(dimethylamino) phenoxy group. Antibacterial experiments demonstrate that this "one-for-two" property endows NanoPcN with excellent antimicrobial efficacy, not only against Gram-positive and Gram-negative bacteria but also against multidrug-resistant bacteria. An ultralow concentration of NanoPcN (50 nM) almost completely inhibited the growth of methicillin-resistant Staphylococcus aureus upon 655 nm laser irradiation (0.5 W/cm²) for 2 min, and the antibacterial effect was significantly stronger than that of the known photosensitizers methylene blue and tetraphenylporphyrin tetrasulfonic acid. Thus, the construction of "one-for-two" materials through a simple molecular structure modification paves a feasible way for the development of effective broad-spectrum antibacterial agents.

Self-assembled porphyrin polymer nanoparticles with NIR-II emission and highly efficient photothermal performance in cancer therapy

The development of new organic nanoagents with extremely high photothermal conversion efficiency and good biocompatibility has gained considerable attention in the area of photothermal cancer therapy. In this work, we designed and synthesized a new porphyrin polymer (P-PPor) with donor-acceptor (D-A) structure. P-PPor displayed intense absorbance in the near-infrared (NIR) region with the maximum peak around at 850 ​nm. Under excitation of 808 ​nm, P-PPor demonstrated the significant fluorescence in the NIR-II region (λ _max ​= ​1015 ​nm), with the fluorescence quantum yield of 2.19%. Due to the presence of hydrophilic PEG chains and hydrophobic alkyl chains in the conjugated skeleton, the amphiphilic P-PPor could self-assemble into the nanoparticles (P-PPor NPs) with good dispersibility in water and enhanced absorption in the NIR region. Moreover, P-PPor NPs exhibited quenched fluorescence because of the aggregation-caused quenching (ACQ) effect, resulting in the distinct photothermal effect. The photothermal conversion efficiency (PCE) of P-PPor NPs was measured as 66% under 808 ​nm laser irradiation, higher than most of PTT agents. The remarkable photothermal effect of P-PPor NPs was further demonstrated in vitro and in vivo using 4T1 tumor mode. Meanwhile, the NIR-II fluorescence imaging in vivo indicated the high distribution of P-PPor NPs in tumor site. These results suggested that P-PPor NPs could effectively damage the cancer cells in mice under 808 ​nm laser irradiation, and did not cause any obvious side effects after phototherapy. Thus, P-PPor NPs could be used as a potential agent in photothermal cancer therapy with high effectiveness and safety.

Organic Nanoparticles Based on D-A-D Small Molecule: Self-Assembly, Photophysical Properties, and Synergistic Photodynamic/Photothermal Effects

Cancer is one of the major diseases threatening human health. Traditional cancer treatments have notable side-effects as they can damage the immune system. Recently, phototherapy, as a potential strategy for clinical cancer therapy, has received wide attention due to its minimal invasiveness and high efficiency. Herein, a small organic molecule (PTA) with a D-A-D structure was prepared via a Sonogashira coupling reaction between the electron-withdrawing dibromo-perylenediimide and electron-donating 4-ethynyl-N,N-diphenylaniline. The amphiphilic organic molecule was then transformed into nanoparticles (PTA-NPs) through the self-assembling method. Upon laser irradiation at 635 nm, PTA-NPs displayed a high photothermal conversion efficiency (PCE = 43%) together with efficient reactive oxygen species (ROS) generation. The fluorescence images also indicated the production of ROS in cancer cells with PTA-NPs. In addition, the biocompatibility and photocytotoxicity of PTA-NPs were evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and live/dead cell co-staining test. Therefore, the as-prepared organic nanomaterials were demonstrated as promising nanomaterials for cancer phototherapy in the clinic.

Dopamine-derived nanoparticles for protection of irradiation-induced intestinal injury by maintaining intestinal homeostasis

Radiotherapy of abdominal and pelvic tumors almost inevitably injures the intestine by oxidative stress and causes inflammation. Regrettably, traditional radioprotective agents for irradiation (IR) induced intestinal injury suffer from challenges...

Bacteria-Triggered Multifunctional Hydrogel for Localized Chemodynamic and Low-Temperature Photothermal Sterilization

Pathogenic infections seriously threaten public health and have been considered as one of the most critical challenges in clinical therapy. Construction of a safe and efficient photothermal antibacterial platform is a promising strategy for treatment of bacterial infections. Considering that high temperature does harm to the normal tissues and cells, herein, a bacteria-triggered multifunctional hydrogel is constructed for low-temperature photothermal sterilization with high efficiency by integrating localized chemodynamic therapy (L-CDT). The hydrogel is constructed by incorporating copper sulfide nanoparticles (CuS_NPs ) with photothermal profile into the network of hyaluronic acid (HA) and Fe³⁺ -EDTA complexes, named as CHFH (CuS_NPs -HA-Fe³⁺ -EDTA hydrogel). Bacteria can be accumulated on the surface of CHFH, which secretes hyaluronidase to decompose the HA and release Fe³⁺ . The Fe³⁺ is reduced into Fe²⁺ in microenvironment of bacteria to trigger Fenton reaction. The generated hydroxyl radicals result in sterilization based on L-CDT within short range. By integrating with photothermal property of CuS_NPs , low-temperature photothermal therapy (LT-PTT) for sterilization is realized, which improves the antibacterial efficiency while minimizes damage to normal tissues. The CHFH is further used to prepare Band aid which effectively promotes the Staphylococcus aureus-infected wound healing process in vivo, confirming the great potential for clinical application.

Recent Strategies to Develop Innovative Photosensitizers for Enhanced Photodynamic Therapy

This review presents a robust strategy to design photosensitizers (PSs) for various species. Photodynamic therapy (PDT) is a photochemical-based treatment approach that involves the use of light combined with a light-activated chemical, referred to as a PS. Attractively, PDT is one of the alternatives to conventional cancer treatment due to its noninvasive nature, high cure rates, and low side effects. PSs play an important factor in photoinduced reactive oxygen species (ROS) generation. Although the concept of photosensitizer-based photodynamic therapy has been widely adopted for clinical trials and bioimaging, until now, to our surprise, there has been no relevant review article on rational designs of organic PSs for PDT. Furthermore, most of published review articles in PDT focused on nanomaterials and nanotechnology based on traditional PSs. Therefore, this review aimed at reporting recent strategies to develop innovative organic photosensitizers for enhanced photodynamic therapy, with each example described in detail instead of providing only a general overview, as is typically done in previous reviews of PDT, to provide intuitive, vivid, and specific insights to the readers.