Tumor Microenvironment Responsive Oxygen-Self-Generating Nanoplatform for Dual-Imaging Guided Photodynamic and Photothermal Therapy

Enhancing Deep-Seated Melanoma Therapy through Wearable Self-Powered Microneedle Patch

Effective treatment of deep-seated tumors relies on enhanced drug penetration in transdermal drug delivery systems. While microneedles (MNs) and iontophoresis techniques have shown improved transdermal drug delivery efficiency, challenges such as skin elasticity, high electrical resistance of the stratum corneum, and external power supply requirements hinder their efficacy in treating deep-seated tumors. In this study, a wearable, self-powered MN patch that integrates a flexible triboelectric nanogenerator (F-TENG) is presented, aimed at advancing deep-seated tumor therapy. MNs are composed of water-soluble materials mixed with negatively charged pH-responsive nanoparticles (NPs) loaded with therapeutic drugs. The F-TENG harnesses personal mechanical movements generate electrical energy. Leveraging the advantages of both MNs and F-TENG, therapeutic NPs can penetrate deep skin locations upon MN patch insertion, releasing drugs rapidly in acidic tumor tissues. Owing to these features, a single administration of the integrated MN-patch in a mouse model with deep-seated melanoma exhibits superior therapeutic efficacy in inhibiting deep-located tumor compared to using the MN-patch alone, indicating promising potential for treating tumors at deep sites.

Combined Photosensitive Gene Therapy Effective Against Triple-Negative Breast Cancer in Mice Model

Introduction

Tumor hypoxia and invasion present significant challenges for the efficacy of photodynamic therapy (PDT) in triple-negative breast cancer (TNBC). This study developed a mitochondrial targeting strategy that combined PDT and gene therapy to promote each other and address the challenges.

Methods

The positively charged amphiphilic material triphenylphosphine-tocopherol polyethylene glycol succinate (TPP-TPGS, TPS) and the photosensitizer chloride e6 (Ce6) formed TPS@Ce6 nanoparticles (NPs) by hydrophobic interaction. They electrostatically condensed microRNA-34a (miR-34a) to form stable TPS@Ce6/miRNA NPs.

Results

Firstly, Ce6 disrupted the lysosomal membrane, followed by successful delivery of miR-34a by TPS@Ce6/miRNA NPs. Meanwhile, miR-34a reduced ROS depletion and further enhanced the effectiveness of PDT. Consequently, the mutual promotion between PDT and gene therapy led to enhanced anti-tumor effects. Furthermore, the TPS@Ce6/miRNA NPs promoted apoptosis by down-regulating Caspase-3 and inhibited tumor cell migration and invasion by down-regulating N-Cadherin. In addition, in vitro and in vivo experiments demonstrated that the TPS@Ce6/miRNA NPs achieved excellent anti-tumor effects. These findings highlighted the enhanced anticancer effects and reduced migration of tumor cells through the synergistic effects of PDT and gene therapy.

Conclusion

Taken together, the targeted co-delivery of Ce6 and miR-34a will facilitate the application of photodynamic and genic nanomedicine in the treatment of aggressive tumors, particularly TNBC.

Synthesis and properties of novel type I photosensitizer polycyclic amide

Herein, we have designed and synthesized a novel type-I photosensitizer (PhPA) via Rh-catalyzed oxidative cyclization of diacetoxyterephthalamide with alkynes. The photoelectric properties, photosensitivity and photodegradation process of PhPA have been systematically investigated. The remarkable fluorescence quenching effect (Φ_PL < 0.01) of PhPA suggests that the intersystem crossing from the singlet excited state to the reactive triplet state is enhanced by the enlarged conjugated backbone. Additionally, the ability of superoxide radical (O₂^-˙) generation was confirmed by electron paramagnetic resonance spectroscopy. Finally, the mechanism of PhPA photo-oxidative degradation via the structure of two metabolites is proposed.

Bioinspired Materials for Wearable Devices and Point-of-Care Testing of Cancer

Wearable, point-of-care diagnostics, and biosensors are on the verge of bringing transformative changes in detection, management, and treatment of cancer. Bioinspired materials with new forms and functions have frequently been used, in both translational and commercial spaces, to fabricate such diagnostic platforms. Engineered from organic or inorganic molecules, bioinspired systems are naturally equipped with biorecognition and stimuli-sensitive properties. Mechanisms of action of bioinspired materials are deeply connected with thermodynamically or kinetically controlled self-assembly at the molecular and supramolecular levels. Thus, integration of bioinspired materials into wearable devices, either as triggers or sensors, brings about unique device properties usable for detection, capture, or rapid readout for an analyte of interest. In this review, we present the basic principles and mechanisms of action of diagnostic devices engineered from bioinspired materials, describe current advances, and discuss future trends of the field, particularly in the context of cancer.

Recent advances in metal-organic frameworks and their composites for the phototherapy of skin wounds

Wound healing is a complex process that greatly affects the normal physiological activities of genes, proteins, signaling pathways, tissues, and organs. Bacterial infection could easily lead to serious tissue damage during wound healing, thus countering wound infections becomes a major challenge for clinicians and nursing professionals. At present, the exploration of highly effective, low toxicity and environment friendly methods for wound healing is attracting considerable interest all over the world. Recently, metal-organic frameworks (MOFs) have presented great potential for treating wound infections due to their unique characteristics of diversified functionality, large specific surface area, and high biocompatibility. These properties endow MOFs/MOF-based composites with an outstanding anti-wound infection effect, which is mainly attributed to the continuously released active components and the exerted catalytic activity with the assistance of phototherapy. In this review, the current progress of MOFs/MOF-based composites for the phototherapy of skin wounds is presented. Firstly, we illustrate the pathophysiological mechanisms, principles of phototherapy and the conventional methods for wound healing. Then, the structures and characteristics of MOFs are systematically summarized. Moreover, the review highlights the recent advances in the application of phototherapy for wound healing (including photodynamic therapy, photothermal therapy, and synergistic therapy) based on various MOFs/MOF-based composites. Finally, the challenges and perspectives are provided for the further development of MOF-based materials for medical application.

Sensitization of Antibiotic-Resistant Gram-Negative Bacteria to Photodynamic Therapy via Perfluorocarbon Nanoemulsion

With the merits of excellent efficacy, safety, and facile implementation, antibacterial photodynamic therapy (APDT) represents a promising means for treating bacterial infections. However, APDT shows an unsatisfactory efficacy in combating antibiotic-resistant Gram-negative bacteria due to their specific cell wall structure. In this work, we report a perfluorocarbon nanoemulsion (Ce6@FDC) used as a multifunctional nanocargo of photosensitizer and oxygen for sensitizing antibiotic-resistant Gram-negative bacteria to APDT. Ce6@FDC was fabricated via ultrasonic emulsification with good colloidal stability, efficient Ce6 and oxygen delivery, and excellent photodynamic activity. Meanwhile, Ce6@FDC could strongly bind with Gram-negative Acinetobacter baumannii (A. baumannii) and Escherichia coli (E. coli) via electrostatic interaction, thus leading to notable photodynamic bactericidal potency upon irradiation. In addition, oxygenated Ce6@FDC also exhibited a remarkable efficacy in eradicating Gram-negative bacteria biofilm, averaging five log units lower than the Ce6 group under identical conditions. Taken together, we demonstrate that photodynamic perfluorocarbon nanoemulsion with oxygen-delivery ability could effectively kill planktonic bacteria and remove biofilm, representing a novel strategy in fighting against antibiotic-resistant Gram-negative bacteria.

Recent advances in metal-organic framework-based materials for anti-staphylococcus aureus infection

The rapid spread of staphylococcus aureus (S. aureus) causes an increased morbidity and mortality, as well as great economic losses in the world. Anti-S. aureus infection becomes a major challenge for clinicians and nursing professionals to address drug resistance. Hence, it is urgent to explore high efficiency, low toxicity, and environmental-friendly methods against S. aureus. Metal-organic frameworks (MOFs) represent great potential in treating S. aureus infection due to the unique features of MOFs including tunable chemical constitute, open crystalline structure, and high specific surface area. Especially, these properties endow MOF-based materials outstanding antibacterial effect, which can be mainly attributed to the continuously released active components and the exerted catalytic activity to fight bacterial infection. Herein, the structural characteristics of MOFs and evaluation method of antimicrobial activity are briefly summarized. Then we systematically give an overview on their recent progress on antibacterial mechanisms, metal ion sustained-release system, controlled delivery system, catalytic system, and energy conversion system based on MOF materials. Finally, suggestions and direction for future research to develop and mechanism understand MOF-based materials are discussed in antibacterial application.

Nanoscale metal-organic frameworks for tumor phototherapy

Metal-Organic Frameworks (MOFs) are constructed from metal ions/cluster nodes and functional organic ligands through coordination bonds. Owing to the advantages of diverse synthetic methods, easy modification after synthesis, large adsorption capacity for heavy metals, and short equilibrium time, considerable attention has recently been paid to MOFs for tumor phototherapy. Through rational tuning of metal ions and ligands, MOFs present abundant properties for various applications. Light-triggered phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is an emerging cancer treatment approach. Nanosized MOFs can be applied as phototherapeutic agents to accomplish phototherapy with excellent phototherapeutic efficacy. This review outlines the latest advances in the field of phototherapy with various metal ion-based MOFs.

Type I Photosensitizers Revitalizing Photodynamic Oncotherapy

Photodynamic therapy (PDT) has shown great potential for tumor treatment with merits of non-invasiveness, high selectivity, and minimal side effects. However, conventional type II PDT relying on ¹ O₂ presents poor therapeutic efficacy for hypoxic tumors due to the oxygen-dependent manner. Alternatively, emerging researches have demonstrated that type I PDT exhibits superiority over type II PDT in tumor treatment owing to its diminished oxygen-dependence. In this review, state-of-the-art studies concerning recent progress in type I photosensitizers are scrutinized, emphasizing the strategies to construct highly effective type I photosensitizers. As the foundation, basic principles of type I PDT are presented, and up-to-date type I photosensitizers are summarized and classified based on their attributes. Then, a literature review of representative type I photosensitizers (including nanomaterials and small molecules) is presented with impetus to delineate their novel designs, action mechanisms, as well as anticancer PDT applications. Finally, the remaining challenges and development directions of type I photosensitizers are outlined, highlighting key scientific issues toward clinical translations.

Organic/inorganic nanohybrids rejuvenate photodynamic cancer therapy

The development of nanotechnology has changed the 100-year-old paradigm of photodynamic therapy (PDT), in which organic/inorganic hybrid nanomaterials have made great contributions. In this review, we first describe the mechanisms of PDT and discuss the limitations of conventional PDT. On this basis, we summarize recent progress in organic/inorganic nanohybrids-based photodynamic agents, highlighting how these nanohybrids can be programmed to overcome challenges in photodynamic cancer therapy.

Designing Hypoxia-Responsive Nanotheranostic Agents for Tumor Imaging and Therapy

Hypoxia, a common feature of most solid tumors, plays an important role in tumor proliferation, metastasis, and invasion, leading to drug, radiation, and photodynamic therapy resistance, and resulting in a sharp reduction in the disease-free survival rate of tumor patients. The lack of sufficient blood supply to the interior regions of tumors hinders the delivery of traditional drugs and contrast agents, interfering with their accumulation in the hypoxic region, and preventing efficient theranostics. Thus, there is a need for the fabrication of novel tumor theranostic agents that overcome these obstacles. Reports, in recent years, of hypoxia-responsive nanomaterials may provide with such means. In this review, a comprehensive description of the physicochemical and biological characteristics of hypoxic tumor tissues is provided, the principles of designing the hypoxia-responsive tumor theranostic agents are discussed, and the recent research into hypoxia-triggered nanomaterials is examined. Additionally, other hypoxia-associated responsive strategies, the current limitations, and future prospects for hypoxia-responsive nanotheranostic agents in tumor treatment are discussed.

Mitochondria-Specific Agents for Photodynamic Cancer Therapy: A Key Determinant to Boost the Efficacy

Mitochondria-targeted photodynamic therapy (Mt-PDT), which enables the photogenerated cytotoxic oxygen species with fatal oxidative damage to block mitochondrial functions, has been considered as a promising method to enhance the anticancer effectiveness. Aiming at the challenges of PDT, in the past few decades, numerous mitochondria-targeting molecular agents have been developed to boost the PDT efficacy via directly destroying the mitochondria or activating mitochondria-mediated cell death pathways. Herein, a review for recent advances of Mt-PDT is highlighted including: mitochondrial targeting design principles and strategies, therapeutic performance of mitochondria-targeted agents-mediated PDT as well as the agent-free Mt-PDT. In addition, it puts together the achievements of the combinatory mitochondria-anchoring PDT and other anticancer strategies, demonstrating the advantages provided by Mt-PDT. The existing challenges are discussed and future settlements for the development of mitochondria-specific agents are also forecasted.

Designing caps for colloidal Au nanoparticles

The plasmonic property of a nanostructure is highly dependent on its morphology, but there are few methods for appending a domain as the "functional group" or modifier. As a means of modulating plasmonic properties, we create and modulate Au hats on Au nanoparticles, including mortarboards, beret hats, helmets, crowns, antler hats and antenna hats. The structural control arises from the active surface growth as a result of dynamic competition between ligand absorption and metal deposition. It allows the continuous tuning of hat morphologies, from the facet-controlled growth of mortarboards, to the spreading-favored growth of beret hats and helmets, and to the vertical growth of pillars in crowns, antler hats and antenna hats. Among these plasmonic nanostructures, the mortarboards show excellent SERS enhancement of 8.1 × 105, which is among the best in colloidal nanostructures; and the antler hats show the photothermal conversion efficiency of 66.2%, which compares favorably with the literature reports.

In situ oxygenating and 808 nm light-sensitized nanocomposite for multimodal imaging and mitochondria-assisted cancer therapy

The efficiency of photodynamic therapy (PDT) is severely constrained due to the innate hypoxic environment, besides the elevated level of glutathione (GSH). To get rid of the hypoxic environment and higher concentrations of GSH in the solid tumors, we propose an approach of oxygen self-sufficient multimodal imaging-guided nanocomposite CaO₂-MnO₂-UCNPs-Ce6/DOX (abbreviated as CaMn-NUC), in which CaO₂ nanoparticles in the hydrophobic layer were seated on the hydrophilic MnO₂ sheet and conjugated with chlorin e6 (Ce6) loaded upconversion nanoparticles (UCNPs-Ce6) via the click chemistry approach. CaMn-NUC was presented to overcome hypoxia and GSH-associated photodynamic resistance due to in situ oxygen generation and GSH reduction of MnO₂ upon endocytosis, and a bulk amount of Mn²⁺ ions generated in the process under acidic tumor environment acts as the MRI contrast agent. Moreover, the MnO₂ sheet protects Ce6 from self-degradation under irradiation; thus, it can be used to switch control of cellular imaging. Afterwards, in a regulated and targeted manner, the chemotherapeutic drug (doxorubicin hydrochloride, DOX) can be released with the degradation of CaMn-NUC in the acidic tumor microenvironment (TME). Thus, we testify a competent nanoplatform employing 808 nm-excited UCNPs-Ce6 for concurrent imaging and PDT in consideration of the large anti-Stokes shifts, deep penetration into biological tissues, narrow emission bands, and high spatial-temporal resolution of the UCNPs. Thus, our proposed nanoplatform postulates a strategy to efficiently kill cancer cells in a concentration- and time-dependent manner via the in situ oxygenation of solid tumor hypoxia to enhance the efficiency of multimodal imaging-guided chemo-photodynamic therapy.

Learning from Nature: Bioinspired Chlorin-Based Photosensitizers Immobilized on Carbon Materials for Combined Photodynamic and Photothermal Therapy

Chlorophylls, which are chlorin-type photosensitizers, are known as the key building blocks of nature and are fundamental for solar energy metabolism during the photosynthesis process. In this regard, the utilization of bioinspired chlorin analogs as photosensitizers for photodynamic therapy constitutes an evolutionary topic of research. Moreover, carbon nanomaterials have been widely applied in photodynamic therapy protocols due to their optical characteristics, good biocompatibility, and tunable systematic toxicity. Herein, we review the literature related to the applications of chlorin-based photosensitizers that were functionalized onto carbon nanomaterials for photodynamic and photothermal therapies against cancer. Rather than a comprehensive review, we intended to highlight the most important and illustrative examples over the last 10 years.

Oxygen-releasing manganese clay hybrid complex triggers p53-mediated cancer cell death in hypoxia

Hypoxia in tumor microenvironment is responsible for resistance to conventional modes of cancer therapeutics. A manganese-clay hybrid compound MHC was shown to generate molecular oxygen in aqueous solution. In this study we have shown that MHC, in hypoxia, causes cancer cell death, through release of molecular oxygen and via p53-dependent apoptosis. MHC treatment of cells results in depletion of mitochondrial membrane potential and inhibition of ROS production, in a cell-specific manner. In hypoxia, the oxygen from MHC releases cells from S-phase arrest thus causing p53-dependent apoptosis. The induction of apoptosis by MHC is higher in p53 Wt/Wt cells when it is compared with p53 Mt/Mt cells. The released oxygen from MHC triggers apoptosis via p53 activation through its enhanced homo-oligomerization, post-translational modifications and nuclear localization. Thus MHC as a cellular oxygen-releasing compound has high potential as a drug for hypoxic tumor regression.

The synthesis of two-dimensional Bi2Te3@SiO2core–shell nanosheets for fluorescence/photoacoustic/infrared (FL/PA/IR) tri-modal imaging-guided photothermal/photodynamic combination therapy

Surface activated Bi₂Te₃nanosheets (NSs) conjugated with chlorin e6 (Ce6) were developed for high-performance tumor theranostics.

Self-assembled injectable biomolecular hydrogels towards phototherapy

Biomolecular hydrogels assembled from biomolecules, such as proteins, peptides, and polysaccharides, are promising candidates for facilitating biomedical applications due to their advantages of high biocompatibility, adjustable mechanical properties, functional diversity, and good degradability. This review focuses on current progress in the field of supramolecular injectable biomolecular hydrogels and their applications in antitumor photodynamic therapy (PDT), photothermal therapy (PTT), combined PDT and PTT, and antibacterial phototherapy with emphasis on biomolecular hydrogelators, injectable behaviors, phototherapeutic functions, and the remaining challenges. We hope that this review can provide useful inspiration for the construction and biological applications of novel photo-functional hydrogels as well as phototherapies.

Fighting Hypoxia to Improve PDT

Photodynamic therapy (PDT) has drawn great interest in recent years mainly due to its low side effects and few drug resistances. Nevertheless, one of the issues of PDT is the need for oxygen to induce a photodynamic effect. Tumours often have low oxygen concentrations, related to the abnormal structure of the microvessels leading to an ineffective blood distribution. Moreover, PDT consumes O2. In order to improve the oxygenation of tumour or decrease hypoxia, different strategies are developed and are described in this review: 1) The use of O2 vehicle; 2) the modification of the tumour microenvironment (TME); 3) combining other therapies with PDT; 4) hypoxia-independent PDT; 5) hypoxia-dependent PDT and 6) fractional PDT.

Facile Phototherapeutic Nanoplatform by Integrating a Multifunctional Polymer and MnO2 for Enhancing Tumor Synergistic Therapy

Recent studies indicate that the synergistic phototherapy (SPT) process can simultaneously generate heat for photothermal therapy (PTT) and singlet oxygen (¹ O₂ ) for photodynamic therapy (PDT) to overcome the recurrence of tumors. However, the hypoxic environment in tumors seriously limits the therapeutic effect of the oxygen-dependent PDT, leading to the domination of PTT in the SPT process. Therefore, it is urgent to develop a novel SPT platform for overcoming hypoxia in tumors and improving the therapeutic effect of both PTT and PDT. In this work, a novel phototherapeutic platform based on a nanocomposite of aza-BODIPY/manganese dioxide (MnO₂ ) is developed via simple electrostatic self-assembly. In this design, MnO₂ nanosheets, which could produce heat and catalyze endogenous hydrogen peroxide (H₂ O₂ ) to generate oxygen, are prepared as a nanocarrier. After being coated with the as-prepared water-soluble aza-BODIPY-based polymer (PPAIB), the obtained MnO₂ @PPAIB performs as a smart phototherapeutic agent for enhancing the efficiency of both PTT and PDT. More importantly, compared to PPAIB, MnO₂ @PPAIB generates more heat and reactive oxygen species to realize the enhanced therapy effects of PTT and PDT. Hence, this work provides a new method to enhance the therapeutic efficacy of SPT by using a polymer/MnO₂ nanoplatform to improve the oxygen concentration and produce more heat.

Recent Advances in Carbon Nanomaterials for Cancer Phototherapy

Carbon nanomaterials have received great attention from the scientific community over the past few decades because of their unique physical and chemical properties. In this minireview, we will summarize the recent progress of the use of various carbon nanomaterials in the field of cancer phototherapy. The structural characteristics of each category and the surface functionalization strategies of these nanomaterials will be briefly introduced before focusing on their therapeutic applications. Recent advances on their use in photothermal therapy, photodynamic therapy, and combined phototherapies are presented. Moreover, a few challenges and perspectives on the development of carbon nanomaterials for future theranostics are also discussed.

Mesoporous semiconductors combined with up-conversion nanoparticles for enhanced photodynamic therapy under near infrared light

Photodynamic therapy (PDT) is a promising and effective method for tumor therapy that relies on the reactive oxygen species (ROS) produced by photosensitizers at specific wavelengths to inhibit tumor cells. Inorganic semiconductive materials are potential photosensitizers that can excellently absorb ultraviolet light to produce ROS to kill cancer cells. However, this strategy is still limited in terms of practical applications due to the weak penetration of ultraviolet light through biological tissue, as well as the hypoxic tumor microenvironment, largely decreasing ROS generation. In this research, novel PDT agents made with mesoporous lanthanide-semiconductor composites are developed to obtain a remarkable amount of generated ROS under near-infrared (NIR) laser irradiation. Due to the larger size (about 120 nm) of the up-conversion material (UCM) used as the substrate, coated with different amounts of semiconductors with mesoporous morphologies, this platform could emit higher blue emission under a 980 nm laser. Meanwhile, both of the semiconductors (SnO₂ and TiO₂) used have wide absorbance bands in the ultraviolet region, and the ultraviolet fluorescence emitted from the UCM core under NIR laser excitation can be used as the energy donor. Electron transfer processes in SnO₂ and TiO₂ are generated via the above platforms and produce ROS through photochemical action. Furthermore, the coated semiconductors are mesoporous with larger surface areas (about 302 m² g⁻¹) and various channels; this is beneficial to obtain enough oxygen to generate more ROS under a hypoxic environment. The PDT efficiency of a typical NaYF₄@SnO₂ sample is studied using a DPBF detector, in vitro MTT assays, and in vivo tumor inhibition experiments, revealing that this lanthanide-semiconductor platform could be potentially used as a PDT agent under NIR excitation.

Photodynamic therapy (PDT) is a promising and effective method for tumor therapy that relies on the reactive oxygen species (ROS) produced by photosensitizers at specific wavelengths to inhibit tumor cells.