Highly biocompatible BSA-MnO2 nanoparticles as an efficient near-infrared photothermal agent for cancer therapy

β-MnO2 nanozyme/Ni2+ mediated formation of TriOPD-Ni2+ polymers for specific and background-free detection of carbaryl

A novel photothermal sensing platform for direct, specific, and background-free detection of carbaryl has been fabricated. Firstly, β-MnO2 with excellent oxidase-like property has been screened out from MnO2 with different crystalline structures. Interestingly, Ni2+ as a chelator with nitrogen atom can modulate the MnO2 catalytic oxidation and assembly of o-phenylenediamine (OPD) to photothermal probe, OPD trimer (triOPD)-Ni2+ polymers, with an excellent photothermal conversion efficiency of 42.4 % under 808 nm laser irradiation. Then, carbaryl was hydrolyzed into reductive 1-naphthol in alkaline condition, which directly decomposed β-MnO2 into Mn2+ and significantly hindered the β-MnO2/Ni2+-mediated production of triOPD-Ni2+ polymers. Consequently, the photothermal effect was linearly correlated with carbaryl concentration in the range of 0.05-4.0 μM with a satisfactory limit of detection at 0.018 μM. Moreover, background-free detection of carbaryl can be achieved in actual food samples with good recovery (96.5%-104.3%), low relative standard deviation (≤1.0%), and excellent anti-interference capacity. The established photothermal sensor will not only provide an efficient method for carbaryl assay but also supply a new pathway for detection pesticides.

Current status and prospects of MOFs loaded with H2O2-related substances for ferroptosis therapy

Ferroptosis is a programmed cell death mechanism characterized by the accumulation of iron (Fe)-dependent lipid peroxides within cells. Ferroptosis holds excellent promise in tumor therapy. Metal-organic frameworks (MOFs) offer unique advantages in tumor ferroptosis treatment due to their high porosity, excellent stability, high biocompatibility, and targeting capabilities. Inducing ferroptosis in tumor cells primarily involves the production of reactive oxygen species (ROS), like hydroxyl radicals (˙OH), through iron-mediated Fenton reactions. However, the intrinsic H2O2 levels in tumor cells are often insufficient to sustain prolonged consumption, limiting therapeutic efficacy if ˙OH production is inadequate. Therefore, catalyzing or supplementing the intracellular H2O2 levels in tumor cells is essential for inducing ferroptosis by nanoscale metal-organic frameworks. This article reviews the biological characteristics and molecular mechanisms of ferroptosis, introduces H2O2-related substances, and reviews MOF-based nanoscale strategies for enhancing intracellular H2O2 levels in tumor cells. Finally, the challenges and prospects of this approach are discussed, aiming to provide insights into improving the effectiveness of ferroptosis induced by MOFs.

Manganese Dioxide-Based Nanomaterials for Medical Applications

Manganese dioxide (MnO2) nanomaterials can react with trace hydrogen peroxide (H2O2) to produce paramagnetic manganese (Mn2+) and oxygen (O2), which can be used for magnetic resonance imaging and alleviate the hypoxic environment of tumors, respectively. MnO2 nanomaterials also can oxidize glutathione (GSH) to produce oxidized glutathione (GSSG) to break the balance of intracellular redox reactions. As a consequence of the sensitivity of the tumor microenvironment to MnO2-based nanomaterials, these materials can be used as multifunctional diagnostic and therapeutic platforms for tumor imaging and treatment. Importantly, when MnO2 nanomaterials are implanted along with other therapeutics, synergetic tumor therapy can be achieved. In addition to tumor treatment, MnO2-based nanomaterials display promising prospects for tissue repair, organ protection, and the treatment of other diseases. Herein, we provide a thorough review of recent progress in the use of MnO2-based nanomaterials for biomedical applications, which may be helpful for the design and clinical translation of next-generation MnO2 nanomaterials.

Tumor targeted nanohybrid for dual stimuli responsive and NIR amplified photothermal/photo-induced thermodynamic/chemodynamic combination therapy

The combination of photodynamic (PDT) and chemodynamic therapy (CDT) for cancer treatment has gathered a lot of attention in recent years. However, its efficacy is severely limited by elevated levels of hypoxia and glutathione (GSH) in the tumor microenvironment (TME). Multifunctional nanoparticles that can help remodel the TME while facilitating PDT/CDT combination therapy are the need of the hour. To this effect, we have developed O2self-supplying, free radical generating nanohybrids that exhibit near infra-red (NIR) triggered photothermal (PTT)/photo-induced thermodynamic (P-TDT) and CDT for efficient breast cancer treatment. The surface of nanohybrids has been further modified by biointerfacing with cancer cell membrane. The biomimetic nanohybrids have been comprehensively characterized and found to exhibit high 2,2'-azobis-[2-(2-imidazolin-2-yl)propane] dihydrochloride (AIPH) loading, GSH depletion, oxygen self-supply with TME responsive AIPH release. Biological activity assays demonstrate efficient cellular uptake with homotypic targeting, excellent hemo- and cytocompatibility as well as high intracellular reactive oxygen species generation with synergistic cytotoxicity against tumor cells. The multifunctional nanohybrid proposed in the present study provides an attractive strategy for achieving NIR responsive, tumor targeted PTT/P-TDT/CDT combination therapy for breast cancer treatment.

Double-enzyme active MnO2@BSA mediated lab-on-paper dual-modality aptasensor for di(2-ethylhexyl)phthalate

Di(2-ethylhexyl)phthalate (DEHP), as an environmental endocrine disruptor, has adverse effects on eco-environments and health. Thus, it is crucial to highly sensitive on-site detect DEHP. Herein, a double-enzyme active MnO2@BSA mediated dual-modality photoelectrochemical (PEC)/colorimetric aptasensing platform with the cascaded sensitization structures of ZnIn2S4 and TiO2 as signal generators was engineered for rapid and ultrasensitive detection of DEHP using an all-in-one lab-on-paper analytical device. Benefitting from cascaded sensitization effect, the ZnIn2S4/TiO2 photosensitive structures-assembled polypyrrole paper electrode gave an enhanced photocurrent signal. The MnO2@BSA nanoparticles (NPs) with peroxidase-mimic and oxidase-mimic double-enzymatic activity induced multiple signal quenching effects and catalyzed color development. Specifically, the MnO2@BSA NPs acted as peroxidase mimetics to generate catalytic precipitates, which not only obstructed interfacial electron transfer but also served as electron acceptors to accept photogenerated electrons. Besides, the steric hindrance effect from MnO2@BSA NPs-loaded branchy polymeric DNA duplex structures further decreased photocurrent signal. The target recycling reaction caused the detachment of MnO2@BSA NPs to increase PEC signal, realizing the ultrasensitive detection of DEHP with a low detection limit of 27 fM. Ingeniously, the freed MnO2@BSA NPs flowed to colorimetric zone with the aid of fluid channels and acted as oxidase mimetics to induce color intensity enhancement, resulting in the rapid visual detection of DEHP. This work provided a prospective paradigm to develop field-based paper analytical tool for DEHP detection in aqueous environment.

Ultrasensitive fluorescence immunoassay of pepsinogen I based on enzyme-triggered decomposition of AuNCs/MnO2

Gastric cancer is a prevalent malignant tumor of the gastrointestinal tract accompanied by a high mortality rate; therefore, early gastric cancer screening is critical for improving patient survival. In this study, we present a facile fluorescence immunoassay for highly sensitive screening of pepsinogen I (PG I) based on a one-pot biomimetic mineralization process for the synthesis of gold nanocluster-anchored manganese dioxide (AuNCs/MnO2) nanosheets. MnO2 first quenches the fluorescence of AuNCs through the Förster resonance energy transfer effect, whereas the introduction of ascorbic acid (AA) leads to the decomposition of MnO2 and rapidly recovers the fluorescence of AuNCs. Based on the above principles and phenomena, we developed a sensitive fluorescence immunoassay for the in situ generation of AA to detect PG I. Specifically, in the presence of PG I, the sandwich-type immunoreactivity-enriched alkaline phosphatase-labeled secondary antibody catalyzes the production of AA from the substrate, which enhances the fluorescence intensity. Under optimized conditions, the fluorescence intensity increased linearly with the concentration of PG I (0.05 to 200 ng mL-1) with a limit of detection (LOD) of 0.013 ng mL-1 (S/N = 3). The designed sensing platform has good stability (more than one year) and excellent anti-interference capability and demonstrates satisfactory accuracy for detection in real samples compared to commercial ELISA kits.

Advances in anti-invasive fungal drug delivery systems

Currently, the first-line drugs for invasive fungal infections (IFI), such as amphotericin B, fluconazole and itraconazole, have drawbacks including poor water solubility, low bioavailability, and severe side effects. Using drug delivery systems is a promising strategy to improve the efficacy and safety of traditional antifungal therapy. Synthetic and biomimetic carriers have greatly facilitated the development of targeted delivery systems for antifungal drugs. Synthetic carrier drug delivery systems, such as liposomes, nanoparticles, polymer micelles, and microspheres, can improve the physicochemical properties of antifungal drugs, prolong their circulation time, enhance targeting capabilities, and reduce toxic side effects. Cell membrane biomimetic drug delivery systems, such as macrophage or red blood cell membrane-coated drug delivery systems, retain the membrane structure of somatic cells and confer various biological functions and specific targeting abilities to the loaded antifungal drugs, exhibiting better biocompatibility and lower toxicity. This article reviews the development of antifungal drug delivery systems and their application in the treatment of IFI, and also discusses the prospects of novel biomimetic carriers in antifungal drug delivery.

ALA/Ag2S/MnO2 Hybrid Nanoparticles for Near-Infrared Image-Guided Long-Wavelength Phototherapy of Breast Cancer

The combination of photothermal therapy (PTT) and photodynamic therapy (PDT) based on temperature increase and the formation of reactive oxygen species (ROS), respectively, is an exciting avenue to provide local and improved therapy of tumors with minimal off-site toxicity. 5-Aminolevulinic acid (ALA) is one of the most popular PDT pro-drugs, and its efficiency improves significantly when delivered to tumors with nanoparticles (NPs). But the tumor site's hypoxic environment is a handicap for the oxygen-consuming PDT process. In this work, highly stable, small, theranostic NPs composed of Ag₂S quantum dots and MnO₂, electrostatically loaded with ALA, were developed for enhanced PDT/PTT combination of tumors. MnO₂ catalyzes endogenous H₂O₂ to O₂ conversion and glutathione depletion, enhancing ROS generation and ALA-PDT efficiency. Ag₂S quantum dots (AS QDs) conjugated with bovine serum albumin (BSA) support MnO₂ formation and stabilization around Ag₂S. AS-BSA-MnO₂ provided a strong intracellular near-infrared (NIR) signal and increased the solution temperature by 15 °C upon laser irradiation at 808 nm (215 mW, 10 mg/mL), proving the hybrid NP as an optically trackable, long-wavelength PTT agent. In the in vitro studies, no significant cytotoxicity was observed in the absence of laser irradiation in healthy (C2C12) or breast cancer cell lines (SKBR3 and MDA-MB-231). The most effective phototoxicity was observed when AS-BSA-MnO₂-ALA-treated cells were co-irradiated for 5 min with 640 nm (300 mW) and 808 nm (700 mW) due to enhanced ALA-PDT combined with PTT. The viability of cancer cells decreased to approximately 5-10% at 50 μg/mL [Ag], corresponding to 1.6 mM [ALA], whereas at the same concentration, individual PTT and PDT treatments decreased the viability to 55-35%, respectively. The late apoptotic death of the treated cells was mostly correlated with high ROS levels and lactate dehydrogenase. Overall, these hybrid NPs overcome tumor hypoxia, deliver ALA to tumor cells, and provide both NIR tracking and enhanced PDT + PTT combination therapy upon short, low-dose co-irradiation at long wavelengths. These agents that may be utilized for treating other cancer types are also highly suitable for in vivo investigations.

In situ photo-crosslinking silk fibroin based hydrogel accelerates diabetic wound healing through antibacterial and antioxidant

Bacterial infection and excessive reactive oxygen species (ROS) in diabetic wounds lead to a prolonged inflammatory phase, and injuries are highly susceptible to developing into chronic wounds. Improving the poor microenvironment is vital to achieving effective diabetic wound healing. In this work, methacrylated silk fibroin (SFMA) was combined with ε-polylysine (EPL) and manganese dioxide nanoparticles (BMNPs) to form an SF@(EPL-BM) hydrogel with in situ forming, antibacterial and antioxidant properties. EPL imparted high antibacterial activity (>96 %) to the hydrogel. BMNPs and EPL showed good scavenging activity against a variety of free radicals. SF@(EPL-BM) hydrogel had low cytotoxicity and could alleviate H₂O₂-induced oxidative stress in L929 cells. In diabetic wounds infected with Staphylococcus aureus (S. aureus), the SF@(EPL-BM) hydrogel exhibited better antibacterial properties and reduced wound ROS levels more significantly than that of the control in vivo. In this process, the pro-inflammatory factor TNF-α was down-regulated, and the vascularization marker CD31 was up-regulated. H&E and Masson staining showed a rapid transition from the inflammatory to the proliferative phase of the wounds, with significant new tissue and collagen deposition. These results confirm that this multifunctional hydrogel dressing holds well potential for chronic wound healing.

Poly-thymine DNA templated MnO2 biomineralization as a high-affinity anchoring enabling tumor targeting delivery

Manganese oxide nanomaterials (MONs) are emerging as a type of highly promising nanomaterials for diseases diagnosis, and surface modification is the basis for colloidal stability and targeting delivery of the nanomaterials. Here, we report the in-situ functionalization of MnO₂ with DNA through a biomineralization process. Using adsorption-oxidation method, DNA templated Mn²⁺ precursor to biomineralize into nano-cubic seed, followed by the growth of MnO₂ to form cube/nanosheet hybrid nanostructure. Among four types of DNA homopolymers, poly-thymine (poly-T) was found to stably attach on MnO₂ surface to resist various biological displacements (phosphate, serum, and complementary DNA). Capitalized on this finding, a di-block DNA was rationally designed, in which the poly-T block stably anchored on MnO₂ surface, while the AS1411 aptamer block was not only an active ligand for tumor targeting delivery, but also a carrier for photosensitizer (Ce6) loading. Upon targeting delivery into tumor cells, the MnO₂ acted as catalase-mimic nanozyme for oxygenation to sensitize photodynamic therapy, and the released Mn²⁺ triggered chemodynamic therapy via Fenton-like reaction, achieving synergistic anti-tumor effect with full biocompatibility. This work provides a simple yet robust strategy to functionalize metal oxides nanomaterials for biological applications via DNA-templated biomineralization.

One-step self-assembly of multilayer graphene oxide via streamlined click reactions for sensitive colorimetric assays

Hemin-loaded graphene oxide with excellent peroxidase-like activity shows great potential for biosensing applications. However, the detection sensitivity of biosensors based on such catalytic methods is limited by the lack of a signal amplification technique. In this work, we developed a simple and rapid signal amplification method based on streamlined click reactions enabling one-step assembly of multilayer graphene oxide nanosheets on magnetic beads to immobilize large amounts of hemin serving as active catalysts, which allowed for the highly sensitive detection of various biological targets, including copper ions, DNA sequences and proteins. With this method, we achieved detection limits down to 13.74 nM, 4.89 pM and 7.77 pg/mL for Cu²⁺, Ebola virus DNA sequences, and carcinoembryonic antigen, respectively. The designed platform holds great promise in the self-assembly of graphene-based nanozymes and sensitive colorimetric biosensing in a wider range of applications.

Facile synthesis of phycocyanin/polydopamine hierarchical nanocomposites for synergizing PTT/PDT against cancer

The exceptional biocompatibility and biosafety of natural proteins have made them a popular choice for tumor therapy in recent years, but their therapeutic effectiveness is severely constrained by factors including physiological instability, insufficient delivery, limited accumulation in tumor cells, etc. Here, a novel Mn-doped phycocyanin (Pc)/polydopamine (PDA) hierarchical nanostructure (MnPc@P) with excellent optical absorption, photothermal conversion, and photodynamic performances, is first designed and fabricated by a simply one-pot reaction, which not only successfully encapsulates natural protein Pc with intact activity in the nanostructure of MnPc@P but also gives them better biocompatibility. Upon laser irradiation, PDA-mediated hyperthermia and Pc-induced ROS elevation in tumor cells have been demonstrated, leading to drastic tumor cell death via combined PTT/PDT effect, greater than single PTT or PDT. In general, the expert fusion of Pc and PDA into a single nanomedicine opens fascinating perspectives in the delivery of natural proteins and tumor therapy.

Modulatory role of Bovine serum albumin conjugated manganese dioxide nanoparticle on microwave radiation induced alterations in reproductive parameters of rat

In recent decades, microwave (MW) radiations are being used extensively for various applications such as Wi-Fi, telecommunication, etc. due to which there have been grave concerns regarding the adverse effects of MW exposure on human health, particularly the reproductive system. MW cause damage to the reproductive system by generating free radicals, decreasing antioxidant defence, and inducing oxidative stress. Hence, the present study was aimed to counteract the harmful effect by using antioxidant enzymes mimicking nanoparticle, Bovine serum albumin (BSA) conjugated manganese dioxide nanoparticle (MNP*). Male Wistar rats were exposed to MW and treated with MNP*, and their individual, as well as combined effect on reproductive parameters was investigated. Results showed that MW exposed rats had significantly reduced testosterone levels along with alterations in the testicular morphology. The antioxidant status decreased, and lipid peroxidation increased significantly in testis. MW exposure also showed altered sperm parameters such as a significant decrease in sperm count, viability, membrane integrity and mitochondrial activity with a significant increase in morphological abnormality and lipid peroxidation. As a result, the changes induced by MW may affect male fertility. However, upon combined exposure of MNP* and MW, these alterations were reduced significantly. Hence, it may be concluded that MNP* could reduce oxidative stress mediated damages in the reproductive system of rats owing to its antioxidant activity, and thus have a potential to act as a radioprotectant.

In-Situ Assembly of Janus Nanoprobe for Cancer Activated NIR-II Photoacoustic Imaging and Enhanced Photodynamic Therapy

Inorganic nanoprobes have attracted increasing attention in the biomedical field due to their versatile functionalities and excellent optical properties. However, conventional nanoprobes have a relatively low retention time in the tumor and are mostly applied in the first near-infrared window (NIR-I, 650-950 nm), limiting their applications in accurate and deep tissue imaging. Herein, we develop a Janus nanoprobe, which can undergo tumor microenvironment (TME)-induced aggregation, hence, promoting tumor retention time and providing photoacoustic (PA) imaging in the second NIR (NIR-II, 950-1700 nm) window, and enhancing photodynamic therapy (PDT) effect. Ternary Janus nanoprobe is composed of gold nanorod (AuNR) coated with manganese dioxide (MnO₂) and photosensitizer pyropheophorbide-a (Ppa) on two ends of AuNR, respectively, named as MnO₂-AuNR-Ppa. In the tumor, MnO₂ could be etched by glutathione (GSH) to release Mn²⁺, which is coordinated with multiple Ppa molecules to induce in situ aggregation of AuNRs. The aggregation of AuNR effectively improves the NIR-II photoacoustic signal in vivo. Moreover, the increased retention time of nanoprobes and GSH reduction in the tumor greatly improve the PDT effect. We believe that this work will inspire further research on specific in situ aggregation of inorganic nanoparticles.

Localized Hyperthermia Induced by Biogenic Synthesized Manganese Oxide Nanoparticles from Cannabis Sativa for Glioblastoma Photothermal Therapy

Glioblastoma is one of the most aggressive and fast-growing types of cancers which required sophisticated and effective therapeutic methods. In this work, we synthesized manganese oxide nanoparticles (MnO2 NPs) using a green synthesis approach. In this process, an aqueous extract of Cannabis sativa (CS) leaves was used as the reacting medium and reducing agent of manganese acetate. The characterizations showed that the synthesized NPs have a diameter of 25–35 nm and high purity. The thermal generating studies showed that the combination of the synthesized biogenic MnO2 NPs with near-infrared laser (NIR, 808 nm) produce considerable heat in a concentration and power density-dependent manner. In vitro studies revealed that the NPs are cytocompatible in concentration up to 80 μg/mL and induce negligible toxicity (p < 0.1). On the other hand, the treatment-induced considerably cell death on C6 glioma cells in an optimum concentration and generated heat (p < 0.05). This study showed the CS extract can synthesis MnO2 NPs and the synthesized NPs can be applied as the effective photothermal agent.

Bovine serum albumin-based biomimetic gene complexes with specificity facilitate rapid re-endothelialization for anti-restenosis

Re-endothelialization is a critical problem to inhibit postoperative restenosis, and gene delivery exhibits great potential in rapid endothelialization. Unfortunately, the therapeutic effect is enormously limited by inefficient specificity, poor biocompatibility and in vivo stability owing largely to the complicated in vivo environment. Herein, we developed a series of platelet membrane (PM) cloaked gene complexes based on natural bovine serum albumin (BSA) and polyethyleneimine (PEI). The gene complexes aimed to accelerate re-endothelialization for anti-restenosis via pcDNA3.1-VEGF165 (VEGF) plasmid delivery. Based on BSA and PM coating, these gene complexes exhibited good biocompatibility, stability with serum and robust homing to endothelium-injured site inherited from platelets. Besides, they enhanced the expression of VEGF protein by their high internalization and nucleus accumulation efficiency, and also substantially promoted migration and proliferation of vascular endothelial cells. The biological properties were further optimized via altering PEI and PM content. Finally, rapid recovery of endothelium in a carotid artery injured mouse model (79% re-endothelialization compared with model group) was achieved through two weeks' treatment by the PM cloaked gene complexes. High level of expressed VEGF in vivo was also realized by the gene complexes. Moreover, neointimal hyperplasia (IH) was significantly inhibited by the gene complexes according to in vivo study. The results verified the great potential of the PM cloaked gene complexes in re-endothelialization for anti-restenosis. STATEMENT OF SIGNIFICANCE: Rapid re-endothelialization is a major challenge to inhibit postoperative restenosis. Herein, a series of biodegradable and biocompatible platelet membrane (PM) cloaked gene complexes were designed to accelerate re-endothelialization for anti-restenosis via pcDNA3.1-VEGF165 (VEGF) plasmid delivery. The PM cloaked gene complexes provided high VEGF expression in vascular endothelial cells (VECs), rapid migration and proliferation of VECs and robust homing to endothelium-injured site. In a carotid artery injured mouse model, PM cloaked gene complexes significantly promoted VEGF expression in vivo, accelerated re-endothelialization and inhibited neointimal hyperplasia due to their good biocompatibility and superior specificity. Overall, the optimized PM cloaked gene complexes overcomes multiple obstacles in gene delivery for re-endothelialization and can be a promising candidate for gene delivery and therapy of postoperative restenosis.

Synthesis of manganese-oxide and palladium nanoparticles co-decorated polypyrrole/graphene oxide (MnO2@Pd@PPy/GO) nanocomposites for anti-cancer treatment

Design and fabrication of novel multifunctional nanomaterials as novel “theranostic nanoagents”with high efficiency and low side effects is important for cancer treatment. Herein, we synthesized manganese-oxide and palladium nanoparticle-co-decorated polypyrrole/graphene oxide (MnO₂@Pd@PPy/GO) nanocomposites, which could be used as a novel “theranostic nanoagent” for cancer treatment. Various spectroscopic and microscopic characterizations of the synthesized MnO₂@Pd@PPy/GO nanocomposites suggest that the nanocomposites are assembled sequentially by graphene oxide, polypyrrole, palladium nanoparticles and manganese-oxide nanoplates. Further research revealed that the nanocomposites had excellent photothermal conversion performance (reached near 50 °C after 10 min of irradiation), pH responsive enzymatic-like catalytic activity and enhanced magnetic resonance imaging (MRI) performance (r₁ = 7.74 mM⁻¹ s⁻¹ at pH 5.0 and glutathione (GSH)). Cell experiments also testified that combined cancer treatment (the viability of cancer cells is 30%) with photothermal therapy (PTT, the viability of cancer cells is 91% only with irradiation) and chemodynamic therapy (CDT, the viability of cancer cells is 74.7% only with nanocomposites) guided by MRI was achieved when the as-prepared nanocomposites were employed as theranostic nanoagents. This work could provide some new ideas for the controllable synthesis and application of multicomponent nanomaterials.

Manganese-oxide and palladium nanoparticle-co-decorated polypyrrole/graphene oxide (MnO₂@Pd@PPy/GO) nanoenzyme composites were synthesized, and could be as a novel “theranostic nanoagent” for cancer treatment due to excellent performance.

Tumor microenvironment-responsive Ag2S-PAsp(DOX)-cRGD nanoparticles-mediated photochemotherapy enhances the immune response to tumor therapy

Chemotherapy drugs play important roles in clinical treatment, and most first-line regimens of cancer therapy contain chemotherapy drugs. In particular, some chemotherapeutic drugs can also produce ICD effect and enhance the immune response of the body. However, most chemotherapy drugs do not specifically target tumors or the complex tumor microenvironment, which renders their curative effect insufficient. Therefore, we constructed a tumor microenvironment-responsive drug delivery system (Ag₂S-PAsp-cRGD) combined with doxorubicin (DOX) for tumor therapy. Firstly, Ag₂S nanoparticles (NPs) were modified with polymer aspartic acid (PAsp) to construct the drug-loading platform. Then, an active targeting ligand (cRGD) was coupled through an amide reaction to enhance the functional targeting ability of the drug delivery system. In vivo imaging of the system showed that the nanoparticles accumulated in the tumor site, which facilitated the delivery of the chemotherapy drug DOX to the targeted tumor site. Furthermore, the photothermal effect of Ag₂S NPs can effectively killed tumor cells, and also helped the release of DOX from nanoparticles into tumor tissue, thus enhancing the chemotherapeutic effect. Moreover, combined with the ICD effect jointly induced by photothermal therapy (PTT) and DOX, the treatment further activated the host immune response against tumors by enhancing the presentation of antigens and promoting the differentiation of T cells. This strategy of photo-chemo-immunotherapy showed excellent antitumor effect, not only eliminating the primary tumor but also preventing recurrence and inhibiting metastasis.

A multifunctional nanoamplifier with self-enhanced acidity and hypoxia relief for combined photothermal/photodynamic/starvation therapy

Phototherapies, including photothermal therapy (PTT) and photodynamic therapy (PDT) have been potential noninvasive therapeutic modality with high efficiency, however, there still exist some intrinsic limitations that impede their clinical applications. Herein, taking the advantages of the synergistic effect and high reactivity of manganese dioxide (MnO₂) nanosheets and glucose oxidase (GOx), multifunctional MPDA@MnO₂-MB-GOx nanoamplifier was constructed for enhanced PTT, PDT, and starvation therapy. In tumor microenvironment (TME), MnO₂ nanosheets on the surface of mesoporous polydopamine (MPDA) could react with endogenous hydrogen peroxide (H₂O₂) and generate oxygen (O₂) to relieve tumor hypoxia, thus enhancing the efficacy of PDT and GOx catalysis. Glucose consumption under the catalysis of GOx will enhance the acidity of TME and increase intracellular H₂O₂ concentration, which in turn promotes the production of O₂ by MnO₂ nanosheets, thus forming efficient cascade reaction and maximizing the efficacy of the functional agents. Furthermore, the heat generated by MPDA under the irradiation of 808 nm laser can accelerate chemical reactions, thus further enhancing synergistic therapeutic efficacy. In vitro/vivo results emphasize that enhanced cancer cell death and tumor inhibition are gained by modulating unfavorable TME with the functional nanosystem, which highlights the promise of the synthesized MPDA@MnO₂-MB-GOx nanomaterial to overcome the limitations of phototherapy.

Manganese-based advanced nanoparticles for biomedical applications: future opportunity and challenges

Nanotechnology is the most promising technology to evolve in the last decade. Recent research has shown that transition metal nanoparticles especially manganese (Mn)-based nanoparticles have great potential for various biomedical applications due to their unique fundamental properties. Therefore, globally, scientists are concentrating on the development of various new manganese-based nanoparticles (size and shape dependent) due to their indispensable utilities. Although numerous reports are available regarding the use of manganese nanoparticles, there is no comprehensive review highlighting the recent development of manganese-based nanomaterials and their potential applications in the area of biomedical sciences. The present review article provides an overall survey on the recent advancement of manganese nanomaterials in biomedical nanotechnology and other fields. Further, the future perspectives and challenges are also discussed to explore the wider application of manganese nanoparticles in the near future. Overall, this review presents a fundamental understanding and the role of manganese in various fields, which will attract a wider spectrum of the scientific community.

Enzymatically synthesised MnO2 nanoparticles for efficient near-infrared photothermal therapy and dual-responsive magnetic resonance imaging

Manganese dioxide (MnO2) nanoparticles (NPs) are highly attractive for biomedical applications due to their biocompatibility, stimuli-responsive magnetic resonance imaging (MRI) properties and capability to modulate the hypoxic tumour microenvironment (TME). However, conventional MnO2 NPs do not possess photothermal therapy (PTT) functions except for hybrids with other photothermal materials. Herein, we first reveal the extraordinary photothermal conversion efficiency (44%) of enzymatically synthesised MnO2 NPs (Bio-MnO2 NPs), which are distinct from chemically synthesised MnO2 NPs. In addition, the Bio-MnO2 NPs revealed high thermal recycling stability and solubility as well as dual pH- and reduction-responsive MRI enhancement for tumour theragnosis. These NPs were prepared through a facile MnxEFG enzyme-mediated biomineralization process. The MnxEFG complex from Bacillus sp. PL-12 is the only manganese mineralization enzyme that could be heterologously overexpressed in its active form to achieve Bio-MnO2 NPs without a bacterial host. The hexagonal layer symmetry of the Bio-MnO2 NPs is the key feature facilitating the high photothermal conversion efficiency and TME-responsive T1-weighted MRI. Evaluations both in vitro at the cellular level and in vivo in a systematic tumour-bearing mouse xenograft model demonstrated the high photothermal ablation efficacy of the Bio-MnO2 NPs, which achieved complete tumour eradication with high therapeutic biosafety without obvious reoccurrence. Moreover, stimuli-responsive MR enhancement potentially allows imaging-guided precision PTT. With their excellent biocompatibility, mild synthesis conditions and relatively simple composition, Bio-MnO2 NPs hold great translational promise.

Recent near-infrared light-activated nanomedicine toward precision cancer therapy

Light has been present throughout the history of mankind and even the universe. It is of great significance to human life, contributing to energy, agriculture, communication, and much more. In the biomedical field, light has been developed as a switch to control medical processes with minimal invasion and high spatiotemporal selectivity. During the past three years, near-infrared (NIR) light as long-wavelength light has been applied to more than 3000 achievements in biological applications due to its deep penetration depth and low phototoxicity. Remotely controlled cancer therapy usually involves the conversion of biologically inert NIR light. Thus, various materials, especially nanomaterials that can generate reactive oxygen species (ROS), ultraviolet (UV)/visual light, or thermal energy and so on under NIR illumination achieve great potential for the research of nanomedicine. Here, we offered an overview of recent advances in NIR light-activated nanomedicine for cancer therapeutic applications. NIR-light-conversion nanotechnologies for both directly triggering nanodrugs and smart drug delivery toward tumor therapy were discussed emphatically. The challenges and future trends of the use of NIR light in biomedical applications were also provided as a conclusion. We expect that this review will spark inspiration for biologists, materials scientists, pharmacologists, and chemists to fight against diseases and boost the future clinical-translational applications of NIR technology-based precision nanomedicine.

Recent Trends in Photoacoustic Imaging Techniques for 2D Nanomaterial-Based Phototherapy

A variety of 2D materials have been developed for therapeutic biomedical studies. Because of their excellent physicochemical properties, 2D materials can be used as carriers for delivering therapeutic agents into a lesion, leading to phototherapy. Various optical imaging techniques have been used for the monitoring of the treatment process. Among these, photoacoustic imaging has unique advantages including relatively deep imaging depth and large field of view with high spatial resolution. In this review article, we summarize the types of photoacoustic imaging systems used for phototherapy monitoring, then we explore contrast-enhanced photoacoustic images using 2D materials. Finally, photoacoustic image-guided phototherapies are discussed. We conclude that 2D material-based phototherapy can be efficiently monitored by photoacoustic imaging techniques.

Injectable Thermosensitive Hydrogel Containing Erlotinib-Loaded Hollow Mesoporous Silica Nanoparticles as a Localized Drug Delivery System for NSCLC Therapy

Erlotinib (ERT), oral administration agents, is one of the most pivotal targeted drugs in the treatment of non-small cell lung cancer (NSCLC); however, its poor solubility, low oral bioavailability, and capricious toxicity limit broader clinical applications. In this paper, a novel injectable matrix is prepared based on hollow mesoporous silica nanoparticles (HMSNs) and thermosensitive poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PDLLA-PEG-PDLLA, PLEL) hydrogel to encapsulate and localize the sustained release of ERT for improved efficacy against NSCLC. The test-tube-inversion method shows that this ERT-loaded hydrogel composite (ERT@HMSNs/gel) presents as an injectable flowing solution under room temperature and transfers into a physically crosslinked non-flowing gel structure at physiological temperature.The ERT@HMSNs/gel composite shows a much longer intratumoral and peritumoral drug retention by in vivo imaging study. Notably, this injectable drug delivery system (DDS) provides an impressive balance between antitumor efficacy and systemic safety in a mice xenograft model. The novel ERT loaded HMSNs/gel system may be a promising candidate for the in situ treatment of NSCLC. Moreover, this study provides a prospective platform for the design and fabrication of a nano-scaled delivery system for localized anticancer therapies.

Ag2S nanoparticle-mediated multiple ablations reinvigorates the immune response for enhanced cancer photo-immunotherapy

Photothermal therapy (PTT) has been widely used in cancer treatment in recent years. However, it is difficult to completely eliminate tumors by single PTT, and the effects of single dose of PTT frequency on the therapeutic outcome of PTT and the multiple PTT-induced immune response in cancer therapy also remain unclear. Here, water-soluble Ag₂S nanoparticles (NPs) with optimal particle size (~15 nm) were synthesized and used as the PTT agents. The in vitro and in vivo results demonstrated that Ag₂S NPs had good photothermal conversion in response to the irradiation of an 808 nm laser, and the results indicated that the NPs have potential as contrast agents for photoacoustic imaging as well as good biocompatibility. The in vivo results further revealed that the frequency of the Ag₂S NP-mediated PTT affected the cancer therapeutic outcome. The increase of frequency efficiently reduced the primary tumor recurrence and alleviated metastasis. The present study suggested that the mechanism involves multiple PTT cycles inhibiting the proliferation of primary tumor cells and stimulating the systematic immune response in the mouse breast cancer model. Therefore, frequency optimization in photothermal ablation may provide a promising strategy to enhance the therapeutic outcome in cancer therapy.

Persistent luminescence-polypyrrole nanocomposite for dual-modal imaging and photothermal therapy of mammary cancer

Multifunctional nanocomposites that possess imaging and high-performance therapeutic features are experiencing a surge in interest in the precision clinical anticancer treatment. In this work, we reported the fabrication and bio-application of a novel persistent luminescence-polypyrrole nanocomposite (LPLNP@SPP) for photoacoustic/persistent luminescence (PA/PL) dual-modal imaging guided photothermal therapy (PTT). The construction of LPLNP@SPP avoids the PL quenching of LPLNP-OH by the polypyrrole-coating, and thus enables the combination of PL and PTT. The LPLNP@SPP shows excellent biocompatibility, long lasting near-infrared (NIR) PL emitting without in situ excitation and high-contrast PA signals. Meanwhile, this nanocomposite exhibits strong NIR absorbance and exceptional photothermal conversion capability, which provides notable potential for imaging-guided antitumor therapy. Thus, our work highlights the dual-functional core-shell LPLNP@SPP as a feasible theranostic nanoplatform for cancer diagnosis and therapy.

Biomedical application of manganese dioxide nanomaterials

Manganese dioxide nanomaterial is a new type of inorganic nanomaterial offering numerous advantages: simple preparation, low cost, and environmental friendliness. This review summarizes the traditional and novel synthetic methods for manganese dioxide nanomaterials and mainly discusses their potential in biomedical applications. Manganese dioxide nanomaterials are mainly used as drug carriers in tumor therapy. In recent years, the construction of multifunctional nano-platforms using manganese dioxide has gradually improved. The main mechanism is that manganese dioxide nanomaterials can combine with reactive oxygen species in the tumor microenvironment to alleviate tumor hypoxia. Manganese dioxide has also been used to quench fluorescent carbon dots in fluorescent probes. Based on the oxidation ability and catalytic activity of MnO₂, MnO₂ nanosheets are widely used to build biosensors. New research shows that manganese dioxide nanomaterials also have great potential in gene therapy and nuclear magnetic imaging.

Facile synthesis of monodisperse chromogenic amylose–iodine nanoparticles as an efficient broad-spectrum antibacterial agent

Monodisperse chromogenic amylose–iodine nanoparticles were developed as an efficient broad-spectrum antibacterial agent under the assistance of near-infrared laser irradiation.

Engineering two-dimensional metal oxides via surface functionalization for biological applications

Schematic illustration of 2D MO nanosheets for applications in biosystems.

Intelligent protein-coated bismuth sulfide and manganese oxide nanocomposites obtained by biomineralization for multimodal imaging-guided enhanced tumor therapy

Radiotherapy (RT) has been used clinically to overcome cancer in recent decades. However, the abnormal tumor microenvironment (TME), involving hypoxia, acidosis and a dense extracellular matrix, is found to be related to the resistance of tumors to RT. Herein, intelligent bovine serum albumin (BSA)-coated Bi₂S₃ and MnO₂ (Bi₂S₃-MnO₂) nanocomposites synthesized via biomineralization are capable of modulating the hypoxic TME effectively to enhance the efficacy of RT. After intravenous injection, the BSA-Bi₂S₃-MnO₂ nanocomposites show efficient accumulation in tumors, where endogenous H₂O₂ can react with MnO₂ to generate oxygen in situ, leading to increased tumor oxygenation to overcome the hypoxia-associated resistance to RT. Moreover, the photothermal effect induced by the BSA-Bi₂S₃-MnO₂ nanocomposites further relieves hypoxia in the TME and, finally, synergistically improves the effects of RT. In this work, we present a simple strategy to fabricate intelligent therapeutic nanoparticles to improve therapeutic efficiency towards cervical cancer.

Rapid and Highly Effective Noninvasive Disinfection by Hybrid Ag/CS@MnO2 Nanosheets Using Near-Infrared Light

A bacterial infection on the surface of medical apparatus and instruments as well as artificial implants is threatening human health greatly. Antibiotics and traditional bacterial-killing agents, even silver nanoparticles, can induce bacterial resistance during long-term interaction with bacteria. Hence, rapid surface sterilization and prevention of bacterial infection in the long term are urgent for biomedical devices, especially for artificial implant materials. Herein, a hybridized chitosan (CS), silver nanoparticles (AgNPs), and MnO₂ nanosheets coating was designed on the surface of titanium plates, which can ensure the implants a rapid and highly effective antibacterial efficacy of 99.00% against Staphylococcus aureus ( S. aureus) and 99.25% against Escherichia coli ( E. coli) within 20 min of 808 nm near-infrared light (NIR) irradiation. The exogenous NIR irradiation can trigger the MnO₂ nanosheets to produce enough hyperthermia within 10 min, which can combine with a low concentration of prereleased Ag⁺ from the coating to achieve superior antimicrobial efficacy through synergistic effects. In contrast, either prereleased Ag ions or a photothermal effect alone can achieve much lower antibacterial efficiency under the same concentration, i.e., 24.00% and 30.01% for the former and 30.00% and 42.54% for the later toward S. aureus and E. coli, respectively. The possible cytotoxicity of coatings could be eliminated owing to the low concentration of AgNPs and chitosan encapsulation. Thus, the novel bifunctional coating Ag/CS@MnO₂ can exhibit great potential in deep site disinfection of Ti implants through the synergy of prereleased Ag ions and a photothermal effect within a short time.

Nanoparticle Therapy for Prostate Cancer: Overview and Perspectives

Traditional prostate cancer therapy and especially chemotherapy has faced many challenges. Low accumulation levels, rapid clearance or drug resistance at the tumor site have been central to why the effect of chemotherapy drugs has declined. Applications of nanotechnology to biomedicine have enabled the development of nanoparticle therapeutic carriers suited for the delivery of chemotherapeutics in cancer therapy. This review describes the current nature of nanoparticle therapeutic carriers for prostate cancer. It describes typical nanocarriers commonly used for the delivery of chemotherapy or for imaging examination. Targeting strategies and related influencing factors are investigated to find ways of enhancing treatment effects of nanoparticles. The overall purpose of this review is to further understanding and to offer recommendations on the design and development of therapeutic nanoparticles for prostate cancer.