SiO2@Cu7S4 nanotubes for photo/chemodynamic and photo-thermal dual-mode synergistic therapy under 808 nm laser irradiation

Flower-like Cu9S8 nanocatalysts with highly active sites for synergistic NIR-II photothermal therapy and chemodynamic therapy

Chemodynamic therapy (CDT) is a promising reactive oxygen species-based therapeutic strategy for tumor therapy. However, the poor reaction kinetics of CDT agents severely restricts its further application. Herein, protamine stabilized flower-like Cu₉S₈ (PS@Cu₉S₈) nanocatalysts are fabricated via a one-pot biomineralization strategy for synergistic second near-infrared (NIR-II) photothermal therapy (PTT) and CDT of tumor. The PS@Cu₉S₈ nanocatalysts possess a high surface area (40.10 m² g^-1), which is higher than those of the previously reported solid and hollow copper sulfide nanoparticles. The high surface area of PS@Cu₉S₈ nanocatalysts increases the number of active sites during the Fenton-like reaction, thereby accelerating the efficiency of CDT. Meanwhile, the PS@Cu₉S₈ nanocatalysts show a high extinction coefficient (21.41 L g^-1 cm^-1) and photothermal conversion efficiency (42.34%), which results in an outstanding PTT efficiency and facilitate ˙OH generation for CDT. Furthermore, RNA-sequencing unveils the whole-genome expression change of 4T1 cells after PS@Cu₉S₈ nanocatalyst treatment, revealing the apparent changes in ROS, cell cycle, and apoptosis-related pathways. In vivo experiments proved the good therapeutic efficiency and negligible systematic toxicity of PS@Cu₉S₈ nanocatalysts. This work not only develops a superior multifunctional nanocatalyst for synergistic PTT and CDT of tumor, but also provides a facile approach to construct high-performance agents for cancer therapy.

Mesoporous nanodrug delivery system: a powerful tool for a new paradigm of remodeling of the tumor microenvironment

Tumor microenvironment (TME) plays an important role in tumor progression, metastasis and therapy resistance. Remodeling the TME has recently been deemed an attractive tumor therapeutic strategy. Due to its complexity and heterogeneity, remodeling the TME still faces great challenges. With the great advantage of drug loading ability, tumor accumulation, multifactor controllability, and persistent guest molecule release ability, mesoporous nanodrug delivery systems (MNDDSs) have been widely used as effective antitumor drug delivery tools as well as remolding TME. This review summarizes the components and characteristics of the TME, as well as the crosstalk between the TME and cancer cells and focuses on the important role of drug delivery strategies based on MNDDSs in targeted remodeling TME metabolic and synergistic anticancer therapy.

A near-infrared triggered upconversion/MoS2 nanoplatform for tumour-targeted chemo-photodynamic combination therapy

The combination of photodynamic therapy and chemotherapy has shown a great potential in cancer treatment. As a promising photosensitizer, MoS₂ quantum dots (QDs) have limited application due to the low tissue penetration of its light absorbing wavelength in the ultraviolet and visible regions. For the purpose of utilizing MoS₂QDs in higher NIR absorption region, herein, we constructed a core/shell nano-photosensitizer upconversion@MoS₂ with doxorubicin loading. This nanoplatform can convert 980 nm NIR into visible light, activating MoS₂QDs to produce reactive oxygen species through fluorescence resonance energy transfer. In addition, this nanoplatform presented good biocompatibility and tumor targeting after polyethylene glycol and folic acid modification. Interestingly, with pH-responsive drug release performance, this nanoplatform presented efficient chemotherapy effects. Thus, the tumour-targeted nanoplatform can achieve up-converted luminescence imaging guided chemo-photodynamic synergistic therapy effectively.

The construct of triple responsive nanocomposite and its antibacterial effect

The current serious mismatch between the increasing severity of bacterial infections and antibiotic production capacity urgently requires the emergence of novel antimicrobial materials. In this paper, dopamine methacrylamide (DMA) and N-isopropylacrylamide (NIPAM) were polymerized as the monomers into a block copolymer poly(dopamine methacrylamide-block-N-isopropylacrylamide) (P(DA-NIP)) and then encapsulated with polydopamine-coated magnetic nanoparticle clusters (MNC) to produce an antibacterial nanocomposite (MNC@P(DA-NIP)). This nanocomposite has triple responses respectively to light, heat and magnetism, which endow MNC@P(DA-NIP) with the abilities to kill bacteria effectively and capture/release bacteria conveniently. Under near-infrared (NIR) light irradiation, MNC@P(DA-NIP) could significantly elevate the temperature through photothermal conversion. The increased temperature favored both the capture of bacteria on MNC@P(DA-NIP), and the damage of bacterial cells, causing bacterial death almost completely. While low temperatures could promote the release of dead bacteria from the nanocomposites, might through the recovery of the hydrophilic state of the outlayer PNIPAM. Moreover, thanks to the magnetic responsibility, MNC@P(DA-NIP) could be easily separated from the bacterial cells and perform better biofilm penetration. The results showed that the antibacterial effect of MNC@P(DA-NIP) was 3.5 times higher than that of MNC, and the recycling capacity of MNC@P(DA-NIP) was better than MNC@PDA. What's more, MNC@P(DA-NIP) possessed the excellent anti-biofilm properties under magnetic field (MF) and NIR. The most important features of the triple-responsive nanocomposites are excellent antibacterial effect, good recyclability and easy preparation, which provide the nanocomposites with great potential in eliminating harmful bacterial cells.

Chemodynamic Therapy via Fenton and Fenton-Like Nanomaterials: Strategies and Recent Advances

Chemodynamic therapy (CDT), a novel cancer therapeutic strategy defined as the treatment using Fenton or Fenton-like reaction to produce •OH in the tumor region, was first proposed by Bu, Shi, and co-workers in 2016. Recently, with the rapid development of Fenton and Fenton-like nanomaterials, CDT has attracted tremendous attention because of its unique advantages: 1) It is tumor-selective with low side effects; 2) the CDT process does not depend on external field stimulation; 3) it can modulate the hypoxic and immunosuppressive tumor microenvironment; 4) the treatment cost of CDT is low. In addition to the Fe-involved CDT strategies, the Fenton-like reaction-mediated CDT strategies have also been proposed, which are based on many other metal elements including copper, manganese, cobalt, titanium, vanadium, palladium, silver, molybdenum, ruthenium, tungsten, cerium, and zinc. Moreover, CDT has been combined with other therapies like chemotherapy, radiotherapy, phototherapy, sonodynamic therapy, and immunotherapy for achieving enhanced anticancer effects. Besides, there have also been studies that extend the application of CDT to the antibacterial field. This review introduces the latest advancements in the nanomaterials-involved CDT from 2018 to the present and proposes the current limitations as well as future research directions in the related field.

The photodynamic/photothermal synergistic therapeutic effect of BODIPY-I-35 liposomes with urea

Phototherapy is a new treatment means for cancer which can reduce the side effects of traditional cancer treatments to humans. Urea is a naturally occurring metabolite in the human body. Some studies have shown that it can inhibit the proliferation of tumor cells and cause oxidative stress. In order to explore the application of urea in enhancing the phototherapy effect, we synthesized a new structure photosensitizer (BODIPY-I-35) with good phototherapeutic effect and encapsulated it in liposomes. Compared with free BODIPY-I-35, water-soluble nanoliposomes (LipoBOD) produced a huge redshift (> 122 nm) of fluorescence emission in solution. When LipoBOD was irradiated with 808 nm laser (1 W/cm²) for 10 min, the temperature contrast increased by 20 °C, which was 4 times higher than free BODIPY-I-35. Confocal microscopy showed appreciable accumulation of LipoBOD in HeLa cells. In addition, when LipoBOD was incubated with urea in HeLa cells, we found that urea not only obviously enhanced the production of ROS, but also increased the apoptosis of HeLa cells. The synergistic effect of LipoBOD (20 μg/mL, at BODIPY-I-35-eq) with urea (250 mM) showed significantly higher phototoxicity than LipoBOD alone. Low dose can reduce the cell viability to 10%. Therefore, we have obtained an effective method of using urea to enhance the phototherapy effect.

Stimulus-responsive nanomaterials under physical regulation for biomedical applications

Cancer is a growing threat to human beings. Traditional treatments for malignant tumors usually involve invasive means to healthy human tissues, such as surgical treatment and chemotherapy. In recent years the use of specific stimulus-responsive materials in combination with some non-contact, non-invasive stimuli can lead to better efficacy and has become an important area of research. It promises to develop personalized treatment systems for four types of physical stimuli: light, ultrasound, magnetic field, and temperature. Nanomaterials that are responsive to these stimuli can be used to enhance drug delivery, cancer treatment, and tissue engineering. This paper reviews the principles of the stimuli mentioned above, their effects on materials, and how they work with nanomaterials. For this aim, we focus on specific applications in controlled drug release, cancer therapy, tissue engineering, and virus detection, with particular reference to recent photothermal, photodynamic, sonodynamic, magnetothermal, radiation, and other types of therapies. It is instructive for the future development of stimulus-responsive nanomaterials for these aspects.

Chemodynamic nanomaterials for cancer theranostics

It is of utmost urgency to achieve effective and safe anticancer treatment with the increasing mortality rate of cancer. Novel anticancer drugs and strategies need to be designed for enhanced therapeutic efficacy. Fenton- and Fenton-like reaction-based chemodynamic therapy (CDT) are new strategies to enhance anticancer efficacy due to their capacity to generate reactive oxygen species (ROS) and oxygen (O2). On the one hand, the generated ROS can damage the cancer cells directly. On the other hand, the generated O2 can relieve the hypoxic condition in the tumor microenvironment (TME) which hinders efficient photodynamic therapy, radiotherapy, etc. Therefore, CDT can be used together with many other therapeutic strategies for synergistically enhanced combination therapy. The antitumor applications of Fenton- and Fenton-like reaction-based nanomaterials will be discussed in this review, including: (iþ) producing abundant ROS in-situ to kill cancer cells directly, (ii) enhancing therapeutic efficiency indirectly by Fenton reaction-mediated combination therapy, (iii) diagnosis and monitoring of cancer therapy. These strategies exhibit the potential of CDT-based nanomaterials for efficient cancer therapy.

Recent research progress in the construction of active free radical nanoreactors and their applications in photodynamic therapy

Photodynamic therapy is the most important treatment strategy in free radical therapy. However, tumor microenvironment hypoxia is a key obstacle in PDT. In order to overcome this obstacle, the strategy of in situ production of O₂/radicals by catalytic reaction in solid tumors was proposed. In recent years, it has been found that there are many oxygen-independent carbon-based free radicals that can generate toxic active free radicals under laser irradiation and lead to tumor cell death. Based on the rational design of multifunctional nano-medicine, the active free radical nano-generator has opened up a new way for the highly developed nanotechnology and tumor cooperative therapy to improve the therapeutic effect. In this paper, the research status of active free radical nano-generators, especially reactive oxygen species, including the construction mechanism of active free radical nanomaterials, is reviewed and the application of free radical nano-generators in tumor therapy is emphasized.