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In the current study, a core-shell inorganic nanostructure comprising a gold nanorod core and -mesoporous manganese dioxide shell was synthesized. Then, the mesoporous manganese dioxide shell was loaded with doxorubicin (DOX) and then coated with pluronic F127 and pluronic F127-folic acid conjugate (1.5:1 wt ratio of pluronic F127: pluronic F127-folic acid conjugate) to prepare targeted final platform. In this design, mesoporous manganese dioxide acted as a reservoir for DOX loading, anti-hypoxia, and MRI contrast agent, while the gold nanorod core acted as a photothermal and CT scan imaging agent. DOX was encapsulated in the mesoporous manganese dioxide shell with a loading capacity and loading efficiency of 19.8 % ± 0.2 and 99.0 % ± 0.9, respectively. The in vitro release experiment showed the impact of glutathione (GSH), mildly acidic pH, and laser irradiating toward accelerated stimuli-responsive DOX release. The ·OH production of the prepared platform was verified by methylene blue (MB) decomposition reaction. Furthermore, thermal imaging exhibited the ability of the prepared platform to convert the NIR irradiation to heat. In vitro cytotoxicity tests on the folate receptor-positive 4 T1 cell line revealed the remarkable cytotoxicity of the targeted formulation compared to the nontargeted formulation (statistically significant). The MTT experiment demonstrated that exposure to laser 808 irradiation enhanced cytotoxicity of the targeted formulation (p < 0.0001). The production of ROS in 4 T1 cells following treatment with the targeted formulation was demonstrated by the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. Furthermore, in vivo investigations by implementing subcutaneous 4 T1 tumorized female BABL/c mice indicated that the prepared platform was an effective system in suppressing tumor growth by combining chemotherapy with PTT (photothermal therapy). Additionally, simultanous PTT and anti-hypoxic activity of this system showed potent tumor growth suppression impact. The percent of tumor size reduction in mice treated with FA-F127-DOX@Au-MnO 2  + 808 nm laser compared to the control group was 99.7 %. The results of the biodistribution investigation showed tumor accumulation and modified pharmacokinetics of the targeted system. Lastly, 6 and 24 h post-intravenous injection, CT-scan and MR imagings capability of the prepared platform was verified in preclinical stage. The prepared multipurpose system introduces great opportunity to provide multiple treatment strategy along with multimodal imaging capability in a single platform for breast cancer treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Detection methods based on CRISPR/Cas12a have been widely developed in the application of pathogenic microorganisms to guarantee food safety and public health. For sensitive detection, the CRISPR-based strategies are often in tandem with amplification methods. However, that may increase the detection time and the process may introduce nucleic acid contamination resulting in non-specific amplification. Herein, we established a sensitive S. aureus detection strategy based on the CRISPR/Cas12a system combined with DNAzyme. The activity of Cas12a is blocked by extending the spacer of crRNA (bcrRNA) and can be reactivated by Mn 2+ . NH 2 -modified S. aureus-specific aptamer was loaded on the surface of Fe 3 O 4 MNPs (apt-Fe 3 O 4 MNPs) and MnO 2 NPs (apt-MnO 2 NPs) by EDC/NHS chemistry. The S. aureus was captured to form apt-Fe 3 O 4 MNPs/S. aureus/apt-MnO 2 NPs complex and then MnO 2 NPs were etched to release Mn 2+ to activate DNAzyme. The active DNAzyme can cleave the hairpin structure in bcrRNA to recover the activity of the CRISPR/Cas system. By initiating the whole detection process by generating Mn 2+ through nanoparticle etching, we established a rapid detection assay without nucleic acid extraction and amplification process. The proposed strategy has been applied in the ultrasensitive quantitative detection of S. aureus and has shown good performance with an LOD of 5 CFU/mL in 29 min. Besides, the proposed method can potentially be applied to other targets by simply changing the recognition element and has the prospect of developing a universal detection strategy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Despite the advancements in cancer therapy, delivering active pharmaceutical ingredients (APIs) using nanoparticles remains challenging due to the failed conveyance of the required drug payload, poor targeting ability, and poor biodistribution, hampering their clinical translation. Recently, the appropriate design of materials with intrinsic therapeutic functionalities has garnered enormous interest in the development of various intelligent therapeutic nanoplatforms. In this study, we demonstrate the fabrication of transition metal (molybdenum, Mo)-doped manganese dioxide (MnO 2 ) nanoarchitectures, exhibiting diagnostic (magnetic resonance imaging, MRI) and therapeutic (chemodynamic therapy, CDT) functionalities. The facile hydrothermal approach-assisted Mo-doped MnO 2 flower-like nanostructures offered tailorable morphologies in altered dimensions, precise therapeutic effects, exceptional biocompatibility, and biodegradability in the tumor microenvironment. The resultant defects due to doped Mo species exhibited peroxidase and oxidase activities, improving glutathione (GSH) oxidation. The two sets of variable valence metal ion pairs (Mn 2+ /Mn 4+ and Mo 5+ /Mo 6+ ) and their interplay could substantially improve the Fenton-like reaction and generate toxic hydroxyl radicals ( • OH), thus achieving CDT-assisted antitumor effects. As inherent T1-MRI agents, these MnO 2 nanoparticles displayed excellent MRI efficacy in vitro . Together, we believe that these conformational Mo-doped MnO 2 nanoarchitectures with two pairs of variable valence states could potentiate drugless therapy in pharmaceutics.

Glutathione (GSH) is one of the most abundant bioethanol antioxidants in living cells. Here, a fluorescent probe based on MnO 2 nanosheets and sulfur quantum dots (SQDs) was fabricated. Because of the synergistic effect of IFE and FRET, the fluorescence from SQDs was quenched by MnO 2 nanosheets. In the presence of GSH, the fluorescence of SQDs could be recovered because of the reduction of MnO 2 nanosheets by GSH. The method can detect GSH in the concentration range of 5 ~ 1000 μM with the detection limit as low as 1.26 μM. This quick, easy, and cost-effective sensor could be used for the quantification of GSH in serum samples and the imaging of GSH in Escherichia coli O157:H7., (© 2024 John Wiley & Sons, Ltd.)

Existing permanganates (MnO 4 - ) sensing methods suffered from the poor selectivity, restricted solubility, and/or less desirable signaling mechanisms (e.g., "turn-off" processes), resulting in the false positive result. In this work, an effective "turn-on" fluorescence method for MnO 4 - detection in aqueous media was proposed via yellow fluorescence carbon dots (Y-CDs) with the maximum emission peak of 553 nm. Upon the introduction of MnO 4 - , the fluorescence of Y-CDs increased significantly due to the enhanced surface passivation degree and intramolecular charge transfer. In the range of 0.1-10 μM, the fluorescence ratio (F/F 0 ) is proportional to the MnO 4 - ions concentration, realizing the "turn-on" fluorescence sensing of MnO 4 - . On the other hand, utilizing the significant color change of Y-CDs by MnO 4 - ions, the colorimetric analysis can also be established for MnO 4 - assay. Compared with other probes, the analysis results obtained by bimodal sensing tactics of fluorescent and colorimetric can be mutually verified to improve the reliability and meet the sensing needs of targets in complex environments., (© 2024 John Wiley & Sons Ltd.)

Purpose: Radiotherapy (RT) is currently recognized as an important treatment for glioblastoma (GBM), however, it is associated with several challenges. One of these challenges is the radioresistance caused by hypoxia, whereas the other is the low conversion efficiency of the strongly oxidized hydroxyl radical (•OH), which is produced by the decomposition of water due to high-energy X-ray radiation. These factors significantly limit the clinical effectiveness of radiotherapy., Results: To address these limitations, we developed a highly stable and efficient nanoplatform (MnO 2 /Pt@BSA). Compared to MnO 2 @BSA, this platform demonstrates high stability, a high yield of oxygen (O 2 ), enhanced production of •OH, and reduced clearance of •OH. The system exhibited increased O 2 production in vitro and significantly improved oxygen production efficiency within 100 s at the Pt loading of 38.7%. Furthermore, compared with MnO 2 , the expression rate of hypoxia-inducible factor (HIF-1α) in glioma cells treated with MnO 2 /Pt decreased by half. Additionally, the system promotes •OH generation and consumes glutathione (GSH), thereby inhibiting the clearance of •OH and enhancing its therapeutic effect. Moreover, the degradation of the nanoplatform produces Mn 2+ , which serves as a magnetic resonance imaging (MRI) contrast agent with a T 1 -weighted enhancement effect at the tumor site. The nanoplatform exhibited excellent biocompatibility and performed multiple functions related to radiotherapy, with simpler components. In U87 tumor bearing mice model, we utilized MnO 2 /Pt nanocatalysis to enhance the therapeutic effect of radiotherapy on GBM., Conclusion: This approach represents a novel and effective strategy for enhancing radiotherapy in gliomas, thereby advancing the field of catalytic radiotherapy and glioma treatment., Competing Interests: The authors report no conflicts of interest in this work., (© 2024 Chen et al.)

Background: Mn 2+ -mediated chemodynamic therapy (CDT) has been emerged as a promising cancer therapeutic modality that relies heavily on HCO 3 - level in the system. Although the physiological buffers (H 2 CO 3 /HCO 3 - ) provide certain amounts of HCO 3 - , the acidity of the tumor microenvironment (TME) would seriously affect the HCO 3 - ionic equilibrium (H 2 CO 3 ⇌ H + + HCO 3 - ). As a result, HCO 3 - level in the tumor region is actually insufficient to support effective Mn 2+ -mediated CDT., Results: In this study, a robust nanomodulator MnFe 2 O 4 @ZIF-8 (PrSMZ) with the capability of in situ self-regulation HCO 3 - is presented to enhance therapeutic efficacy of Mn 2+ -mediated CDT. Under an acidic tumor microenvironment, PrSMZ could act as a proton sponge to shift the HCO 3 - ionic equilibrium to the positive direction, significantly boosting the generation of the HCO 3 - . Most importantly, such HCO 3 - supply capacity of PrSMZ could be finely modulated by its ZIF-8 shell thickness, resulting in a 1000-fold increase in reactive oxygen species (ROS) generation. Enhanced ROS-dependent CDT efficacy is further amplified by a glutathione (GSH)-depletion ability and the photothermal effect inherited from the inner core MnFe 2 O 4 of PrSMZ to exert the remarkable antitumor effect on mouse models., Conclusions: This work addresses the challenge of insufficient HCO 3 - in the TME for Mn 2+ -mediated Fenton catalysts and could provide a promising strategy for designing high-performance Mn 2+ -mediated CDT agents to treat cancer effectively., (© 2024. The Author(s).)

In this study, a novel aptasensor based on a transition metal oxide-modified pencil graphite electrode (PGE) was developed for the diagnosis of early-stage prostate cancer (PCa) via monitoring the prostate-specific antigen (PSA), which is the main biomarker for PCa. Single-use PGEs modified with pulsed deposited manganese oxide (MnOx) film were used to attach the amino-terminated aptamer specific to the PSA via carbodiimide chemistry. The designed aptasensor was placed in an electrochemical cell containing ferri/ferrocyanide ions as a redox probe to measure the charge transfer resistances (R ct ) of the electrode surface by electrochemical impedance spectroscopy (EIS) to follow the response of each modification step. The effect of the medium pH on the ionic structure of the aptamer molecule according to its pI value and, thus, the reversing of the direction of the response (ΔR ct ) by the pH change was also discussed. The level of PSA secreted from PCa cells was investigated using impedimetric transduction. The specificity of the aptasensor was validated through selectivity studies against non-specific tumor markers like VEGF and different cancer cell lines including breast cancer and androgen-insensitive prostate cancer. The developed system showcases a label-free, fast, specific, and cost-effective approach for PSA detection, highlighting the importance of medium pH and the electrostatic environment on the aptamer's response. Our work emphasizes the potential for such aptasensors in clinical diagnostics and paves the way for further exploration into using transition metal oxides in biosensing applications., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

STING agonists can activate natural and adaptive immune responses, and are expected to become a new type of immunotherapy drug for tumor therapy. However, how to target deliver STING agonists to tumor tissues is a key factor affecting the efficacy of tumor treatment. Sonodynamic therapy (SDT) has become a research hotspot in the field of cancer treatment due to its non-invasive, spatiotemporally controllable, and high tissue penetration capabilities. Therefore, how to choose the appropriate drug delivery strategy, build a suitable drug delivery system to co-deliver photosensitizers and STING agonists, is a challenge faced in the tumor treatment. In this study, we developed an albumin-based nanodelivery system named FA-ICG&MnOx@HSA that co-loaded the sonosensitizers indocyanine green (ICG) and manganese oxide (MnOx). This approach achieved folate receptor-targeting mediated tumor delivery and tumor microenvironment (TME)-responsive release facilitated by high levels of glutathione (GSH) and hydrogen peroxide (H 2 O 2 ), which catalyze oxygen generation to potentiate SDT efficacy in killing tumors and inducing immunogenic cell death (ICD). Simultaneously, the released Mn 2+ acted as a STING agonist promoting dendritic cell maturation, IFN-β production, and proliferation of T cells. Ultimately, this albumin based co-loaded sonosensitizer and STING agonist demonstrated promising potential for advancing tumor treatment., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The present study aims to analyze the interaction between Rhodotorula toruloides and magnetic nanoparticles and evaluate their effect on carotenoid production. The manganese ferrite nanoparticles were synthesized without chitosan (MnFe 2 O 4 ) and chitosan coating (MnFe 2 O 4 -CS) by the co-precipitation method assisted by hydrothermal treatment. XRD (X-ray diffraction), Magnetometry, Dynamic Light Scattering (DLS) and FTIR (Fourier-Transform Infrared Spectroscopy), are used to characterize the magnetic nanoparticles. The crystallite size of MnFe 2 O 4 was 16 nm for MnFe 2 O 4 and 20 nm for MnFe 2 O 4 -CS. The magnetic saturation of MnFe 2 O 4 -CS was lower (39.6 ± 0.6 emu/g) than the same MnFe 2 O 4 nanoparticles (42.7 ± 0.3 emu/g), which was attributed to the chitosan fraction presence. The MnFe 2 O 4 -CS FTIR spectra revealed the presence of the characteristic chitosan bands. DLS demonstrated that the average hydrodynamic diameters were 344 nm for MnFe 2 O 4 and 167 nm for MnFe 2 O 4 -CS. A kinetic study of cell immobilization performed with their precipitation with a magnet demonstrated that interaction between magnetic nanoparticles and R. toruloides was characterized by an equilibrium time of 2 h. The adsorption isotherm models (Langmuir and Freundlich) were fitted to the experimental values. The trypan blue assay was used for cell viability assessment. The carotenoid production increased to 256.2 ± 6.1 µg/g dry mass at 2.0 mg/mL MnFe 2 O 4 -CS. The use of MnFe 2 O 4 -CS to stimulate carotenoid yeast production and the magnetic separation of biomass are promising nanobiotechnological alternatives. Magnetic cell immobilization is a perspective technique for obtaining cell metabolites., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A pilot-scale filtration system was adopted to prepare filter media with catalytic activity to remove manganese (Mn 2+ ) and ammonium (NH 4 + -N). Three different combinations of oxidants (KMnO 4 and K 2 FeO 4 ) and reductants (MnSO 4 and FeCl 2 ) were used during the start-up period. Filter R3 started up by KMnO 4 and FeCl 2 (Mn 7+ →MnO x ) exhibited excellent catalytic property, and the NH 4 + -N and Mn 2+ removal efficiency reached over 80% on the 10 th and 35 th days, respectively. Filter R1 started up by K 2 FeO 4 and MnSO 4 (MnO x ←Mn 2+ ) exhibited the worst catalytic property. Filter R2 started up by KMnO 4 and MnSO 4 (Mn 7+ →MnO x ←Mn 2+ ) were in between. According to Zeta potential results, the Mn-based oxides (MnO x ) formed by Mn 7+ →MnO x performed the highest pH IEP and pH PZC . The higher the pH IEP and pH PZC , the more unfavorable the cation adsorption. However, it was inconsistent with its excellent Mn 2+ and NH 4 + -N removal abilities, implying that catalytic oxidation played a key role. Combined with XRD and XPS analysis, the results showed that the MnO x produced by the reduction of KMnO 4 showed early formation of buserite crystals, high degree of amorphous, high content of Mn 3+ and lattice oxygen with the higher activity to form defects. The above results showed that MnO x produced by the reduction of KMnO 4 was more conducive to the formation of active species for catalytic oxidation of NH 4 + -N and Mn 2+ removal. This study provides new insights on the formation mechanisms of the active MnO x that could catalytic oxidation of NH 4 + -N and Mn 2+ ., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Developing multifunctional, stimuli-responsive nanomedicine is intriguing because it has the potential to effectively treat cancer. Yet, poor tumor penetration of nanodrugs results in limited antitumor efficacy. Herein, an oxygen-driven silicon-based nanomotor (Si-motor) loaded with MnO and CaO 2 nanoparticles is developed, which can move in tumor microenvironment (TME) by the cascade reaction of CaO 2 and MnO. Under acidic TME, CaO 2 reacts with acid to release Ca 2+ to induce mitochondrial damage and simultaneously produces O 2 and H 2 O 2 , when the loaded MnO exerts Fenton-like activity to produce ·OH and O 2 based on the produced H 2 O 2 . The generated O 2 drives Si-motor forward, thus endowing active delivery capability of the formed motors in TME. Meanwhile, MnO with glutathione (GSH) depletion ability further prevents reactive oxygen species (ROS) from being destroyed. Such TME actuated Si-motor with enhanced cellular uptake and deep penetration provides amplification of synergistic oxidative stresscaused by intracellular Ca 2 +  overloading, GSH depletion induced by Mn 2+ , and Mn 2+  mediated chemodynamic treatment (CDT), leading to excellent tumor cell death. The created nanomotor may offer an effective platform for active synergistic cancer treatment., (© 2024 Wiley‐VCH GmbH.)

The nanozyme-linked aptamer-sorbent assay (NLASA) is a rapid way to screen and characterize aptamer binding to targets. In this paper, a MnO 2 @AuNPs@aptamer (Apt) based NLASA coupled with colorimetric-SERS dual-mode for Staphylococcus aureus (S. aureus) detection is presented. Cu,Fe-CDs were used as the reducing agent to synthesize MnO 2 and gold nanoparticles (AuNPs). Then, they were fabricated to obtain MnO 2 @AuNPs with oxidase (OXD)-like and SERS activities. The S. aureus aptamer was conjugated to MnO 2 @AuNPs and enhanced the OXD-like activity, which realized the specific capture of S. aureus in food matrices. In addition, S. aureus improves the oxidation of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid (ABTS) but inhibits 3,3',5,5'-tetramethylbenzidine (TMB) to generate Raman-active oxTMB with MnO 2 @AuNPs@Apt. This sensor was used for detections of S. aureus in a concentration ranged from 10 1 to 10 7  CFU/mL with a detection limit of 0.926 CFU/mL (colorimetric) and 1.561 CFU/mL (SERS), and the recovery is 85%-105% in real samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Atherosclerosis (AS) poses a significant threat to human life and health. However, conventional antiatherogenic medications exhibit insufficient targeting precision and restricted therapeutic effectiveness. Moreover, during the progression of AS, macrophages undergo polarization toward the proinflammatory M1 phenotype and generate reactive oxygen species (ROS) to accelerate the occurrence of inflammatory storms, and ingest excess lipids to form foam cells by inhibiting cholesterol efflux. In our study, we developed a macrophage membrane-functionalized hollow mesoporous manganese dioxide nanomedicine (Col@HMnO 2 -MM). This nanomedicine has the ability to evade immune cell phagocytosis, enables prolonged circulation within the body, targets the inflammatory site of AS for effective drug release, and alleviates the inflammatory storm at the AS site by eliminating ROS. Furthermore, Col@HMnO 2 -MM has the ability to generate oxygen autonomously by breaking down surplus hydrogen peroxide generated at the inflammatory AS site, thereby reducing the hypoxic microenvironment of the plaque by downregulating hypoxia-inducible factor (HIF-1α), which in turn enhances cholesterol efflux to inhibit foam cell formation. In an APOE -/- mouse model, Col@HMnO 2 -MM significantly reduced inflammatory factor levels, lipid storage, and plaque formation without significant long-term toxicity. In summary, this synergistic treatment significantly improved the effectiveness of nanomedicine and may offer a novel strategy for precise AS therapy., (© 2024. The Author(s).)

Conventional methods for detecting unsaturated fatty acids (UFAs) pose challenges for rapid analyses due to the need for complex pretreatment and expensive instruments. Here, we developed an intelligent platform for facile and low-cost analysis of UFAs by combining a smartphone-assisted colorimetric sensor array (CSA) based on MnO 2 nanozymes with "image segmentation-feature extraction" deep learning (ISFE-DL). Density functional theory predictions were validated by doping experiments using Ag, Pd, and Pt, which enhanced the catalytic activity of the MnO 2 nanozymes. A CSA mimicking mammalian olfactory system was constructed with the principle that UFAs competitively inhibit the oxidization of the enzyme substrate, resulting in color changes in the nanozyme-ABTS substrate system. Through linear discriminant analysis coupled with the smartphone App "Quick Viewer" that utilizes multihole parallel acquisition technology, oleic acid (OA), linoleic acid (LA), α-linolenic acid (ALA), and their mixtures were clearly discriminated; various edible vegetable oils, different camellia oils (CAO), and adulterated CAOs were also successfully distinguished. Furthermore, the ISFE-DL method was combined in multicomponent quantitative analysis. The sensing elements of the CSA (3 × 4) were individually segmented for single-hole feature extraction containing information from 38,868 images of three UFAs, thereby allowing for the extraction of more features and augmenting sample size. After training with the MobileNetV3 small model, the determination coefficients of OA, LA, and ALA were 0.9969, 0.9668, and 0.7393, respectively. The model was embedded in the smartphone App "Intelligent Analysis Master" for one-click quantification. We provide an innovative approach for intelligent and efficient qualitative and quantitative analysis of UFAs and other compounds with similar characteristics.

Between 2015 and 2017, 90% of Chinese adults were reported to have periodontitis of varying degrees, highlighting the importance of novel, inexpensive, and affordable treatments for the public. The fact that more and more pathogens are becoming resistant to antibiotics further highlights this prevalence. This article addresses a novel micromotor capable of generating reactive oxygen species, as proven by a Fenton-like reaction. Such reactions allow the targeting of Gram-negative bacteria such as Escherichia coli , which are eliminated order of magnitude more effectively than by pure hydrogen peroxide, thereby addressing pathogens relevant in oral infections. The basis of the micromotors, which generate reactive oxygen species on site, reduces the likelihood of resistance developing in these types of bacteria. Catalytically reducing hydrogen peroxide in this process, these micromotors propel themselves forward. This proof of principle study paves the way for the utilization of micromotors in the field of skin disinfection utilizing hydrogen peroxide concentrations which were in previous works proven noncytotoxic.

DNA walkers have attracted considerable attention in biosensing and bioimaging. Compared with the conventional single leg-based DNA walker, the bipedal DNA walker has remarkable advantages, with improved sensitivity and fast kinetics, and can work efficiently in a crowded cellular environment. However, most reported bipedal DNA walkers are powered by exogenous supplementation, and elaborate DNA sequence designs, auxiliary additives or extra carriers are often needed. A highly integrated bipedal DNA walker that can address robustness, sensitivity and consistency issues in a single system is highly desirable but remains a great challenge. We herein report a novel bipedal DNA nanowalker system through simple assembly of a DNA substrate, hairpin functionalized-AuNPs (AuNPs-H2), and a blocked Mn 2+ -dependent DNAzyme hairpin (H1) on degradable MnO 2 nanosheets, which holds great potential for living cell operation. Highly integrated features enable the simultaneous delivery of core components of the bipedal DNA walker, including a walking track (AuNPs-H2), a walking strand (H1 cleaved by APE1), and a driving force (Mn 2+ -dependent DNAzyme cleavage) as a whole, thereby enhancing the control of the spatiotemporal distribution of these components at the intracellular target sites. The redox reaction between the MnO 2 nanosheets and GSH inside the cells not only consumed the intracellular GSH to improve the biostability of the walking track but also generated abundant Mn 2+ as a cofactor of the DNAzyme. As a proof of concept, the developed nanowalker was demonstrated to work efficiently for monitoring base excision repair (BER)-related human apurinic/apyrimidinic endonuclease 1 (APE1) in living cells, highlighting the great potential of the bipedal DNA nanowalker in biological systems., (© 2024. The Author(s).)

Methidathion (MTDT), a common organophosphorus pesticide with high insecticidal activity, is widely used for pest control. However, the misuse of MTDT leads to widespread residues and endangers human health. Therefore, it is crucial to develop a simple and highly sensitive method for the detection of MTDT residues. Herein, ZIF-90/MnO 2 /g-C 3 N 4 /Fe 3 O 4 composite particles were synthesized: The  MnO 2 nanosheets could absorb the energy of the excited g-C 3 N 4 to quench the ECL of g-C 3 N 4 while ZIF-90 acted as a mimetic enzyme to catalyze the formation of thiocholine from MTDT. The thiocholine caused the reduction of MnO 2 to Mn 2+ , restoring the ECL signal of g-C 3 N 4 . Combined with molecular imprinting technique, an electrochemiluminescence sensor was constructed for the determination of MTDT. The determination range was 1.00 × 10 -9  ~ 7.00 × 10 -7  g/L, and the detection limit was 6.58 × 10 -10  g/L. Structurally similar organophosphorus pesticides showed no cross-reactivity. The method has high sensitivity and specificity, and has been successfully applied to the determination of MTDT residue in fruits with recoveries in the range 93.75% ~ 102.37%., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Ultrahigh field magnetic resonance imaging (UHF-MRI) (≥7 T) can dramatically boost image resolution and signal-to-noise ratio, which have distinct advantages in multifunctional imaging. However, their research and application are currently limited by the absence of high-field contrast agents (CAs) and the low sensitivity and accuracy of T1/T2 single-modality CAs. Therefore, the development of T1-T2 dual-mode CAs that respond to UHF-MRI and nanoformulations with therapeutic sensitization can bring ideas for the integrated application of precise and synchronous tumor theranostics. Herein, we present a biomimetic mineralization strategy for synthesizing holmium/manganese oxide-bovine serum albumin-photosensitizer chlorin e6 nanohybrids. The hybrid nanoparticles exhibited better tumor accumulation, a suitable time imaging window, and excellent pH-response T1-T2 dual-mode UHF-MRI performance. The antitumor effect comes from the amelioration of the hypoxic tumor microenvironment to promote the synergistic effect of photodynamic therapy and radiotherapy, along with negligible acute toxicity. Undoubtedly, this work not only provides a different perspective for developing multifunctional nanotherapeutics but also promotes the potential clinical exploitation and translation of UHF CAs.

Manganese dioxide (MnO 2 ), renowned for its abundant natural crystal phases, emerges as a leading catalyst candidate for the degradation of pollutants. The relationship between its crystal phase and catalytic activity, particularly for periodate activation, has remained both ambiguous and contentious. This study delineates the influence of various synthetic MnO 2 phase structures on their capabilities in catalyzing periodate-assisted pollutant oxidation. Five distinct MnO 2 phase structures (α-, β-, γ-, δ-, and ε-MnO₂) were prepared and evaluated to activate periodate and degrade pollutants, following the sequence: α-MnO₂ > γ-MnO₂ > β-MnO₂ > ε-MnO₂ > δ-MnO₂. Through quenching experiments, electron paramagnetic resonance tests, and in situ electrochemical studies, we found an electron transfer-mediated process drive pollutant degradation, facilitated by a highly reactive metastable intermediate complex (MnO₂/PI*). Quantitative structure-activity relationship analysis further indicated that degradation efficiency is strongly associated with both the crystal phase and the Mn (IV) content, highlighting it as a key active site. Moreover, the α-MnO₂ phase demonstrated exceptional recycling stability, enabling an effective pollutant removal in a continuous flow packed-bed reactor for 168 h. Thus, α-MnO₂/PI proved highly effective in mineralizing organic pollutants and reducing their toxicities, highlighting its significant potential for environmental remediation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

In this work, we present a novel colorimetric sensing platform for the sensitive detection of ethamsylate (ETM) usingultrathin MnO 2 nanosheets with enhancedoxidase-mimicking activity. A facile template-free hydrothermal process was applied to synthesize the MnO 2 nanosheets under mild conditions. The nanosheets exhibited oxidase-mimicking activity, facilitating the conversion of TMB into the blue-colored oxTMB in the absence of H 2 O 2 . However, the presence of ETM inhibited this activity, resulting in the conversion of oxTMB back to colorless TMB and a substantial decrease in the blue color intensity. The colorimetric response exhibited a linear relationship with ETM concentration over the range of 0.5 to 10.0 µg/mL and a detection limit of 0.156 µg/mL. To further elucidate the underlying mechanism, we performed extensive characterization and kinetic experiments. The findings demonstrated that this unique property is attributed to the remarkable capacity of the MnO 2 nanosheets to absorb oxygen, producing superoxide radicals (O 2 - ). The oxidase-mimicking activity of the nanosheets was further confirmed by the reaction kinetics, following Michaelis-Menten's behavior. Moreover, the applicability of the sensing platform was assessed by determining ETM concentrations in various real samples (different pharmaceuticals, human plasma, and environmental water). The well-established platform demonstrates the prospective role that nanomaterials-based sensing platforms may play in clinical diagnostics, pharmaceutical analysis, and other relevant fields., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Multidrug-resistant (MDR) bacteria-infected wound healing remains greatly challenging, especially in diabetic patients. Herein, a novel nano-drug delivery based on endogenous glucose-driven cascade reaction is proposed for boosting MDR bacteria-infected diabetic wound healing with high efficacy by improving wound microenvironment and enhancing photodynamic antibacterial activity. The composite nanoagent is first self-assembled by integrating berberine (BBR) and epigallocatechin gallate (EGCG) from natural plant extracts, named as BE NPs , which is successively coated with manganese dioxide nanoshells (MnO 2 NSs ) and glucose oxidase (GOX) to form the final BEMG NPs . The cascade reaction is triggered by glucose at the wound site of diabetes which is specifically catalyzed by GOX in the BEMG NPs to produce gluconic acid and hydrogen peroxide (H 2 O 2 ). That is subsequently to decompose MnO 2 NSs in the BEMG NPs to generate oxygen (O 2 ). The BEMG NPs as photosensitizers effectively produce reactive oxygen species (ROS) to enhance the eradication of bacteria with the assistance of O 2 . Under the synergistic function of the cascaded reaction, the BEMG NPs present excellent antibacterial efficacy even for MDR bacteria. The in vivo experiments explicitly validate that the constructed nano-drug delivery can augment the MDR bacteria-infected diabetic wound healing with excellent biosafety. The as-proposed strategy provides an instructive way to combat ever-threatening MDR bacteria, which particularly is beneficial for diabetic patients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Hierarchical porous carbon derived from discarded biomass for energy storage materials has attracted increasing research attention due to its cost-effectiveness, ease of fabrication, environmental protection, and sustainability. Brewed tea leaves are rich in heteroatoms that are beneficial to capacitive energy storage behavior. Therefore, we synthesized high electrochemical performance carbon-based composites from Tie guan yin tea leaf waste using a facile procedure comprising hydrothermal, chemical activation, and calcination processes. In particular, potassium permanganate (KMnO 4 ) was incorporated into the potassium hydroxide (KOH) activation agent; therefore, during the activation process, KOH continued to erode the biomass precursor, producing abundant pores, and KMnO 4 synchronously underwent a redox reaction to form MnO nanoparticles and anchor on the porous carbon through chemical bonding. MnO nanoparticles provided additional pseudocapacitive charge storage capabilities through redox reactions. The results show that the amount of MnO produced is proportional to the amount of KMnO 4 incorporated. However, the specific surface area of the composite material decreases with the incorporated amount of KMnO 4 due to the accumulation and aggregation of MnO nanoparticles, thereby even blocking some micropores. Optimization of MnO nanocrystal loading can promote the crystallinity and graphitization degree of carbonaceous materials. The specimen prepared with a weight ratio of KMnO 4 to hydrochar of 0.02 exhibited a high capacitance of 337 F/g, an increase of 70%, owing to the synergistic effect between the Tie guan yin tea leaf-derived activated carbon and MnO nanoparticles. With this facile preparation method and the resulting high electrochemical performance, the development of manganese oxide/carbon composites derived from tea leaf biomass is expected to become a promising candidate as an energy storage material for supercapacitors.

Magnetic Co0.5Mn0.5Fe2O4 nanoparticles were successfully prepared via the combustion and calcination process, with an average particle diameter of 31.5 nm and a saturation magnetization of 25.25 emu·g-1, they were employed to adsorbe Congo red (CR) from wastewater, the Pseudo-second-order kinetic and Freundlich isotherm were consistent with the adsorption data, indicating that their adsorption was a multilayer chemisorption process, the thermodynamic investigation showed that the adsorption was a favored exothermic process. The ionic strength of Cl- in CR solution had no obvious effect on the adsorption efficiency of Co0.5Mn0.5Fe2O4 nanoparticles, and the maximum adsorbance was 58.3 mg·g-1 at pH 2, decreasing as the pH of the CR solutions increased from 2 to 12. The ion leaching experiment and XRD demonstrated that Co0.5Mn0.5Fe2O4 nanoparticles had excellent stability, and the relative removal rate was 93.85% of the first time after 7 cycles. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrated that CR was adsorbed onto Co0.5Mn0.5Fe2O4 nanoparticles, and the electrical conductivity of Co0.5Mn0.5Fe2O4 nanoparticles decreased after adsorption of CR. Magnetic Co0.5Mn0.5Fe2O4 nanoparticles displayed a promising application in wastewater treatment., Competing Interests: The authors do not declare any conflict of interest., (Copyright: © 2024 Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Redox-inactive metal-ion-driven modulation of the oxidation behavior of high-valent metal-oxo complex has garnered significant interest in biological and chemical synthesis; however, their role in permanganate (Mn(VII)) oxidation for the removal of organic pollutants has been largely neglected. Here, we uncover the impact of six metal ions (i.e., Ca 2+ , Mg 2+ , Ni 2+ , Zn 2+ , Al 3+ , and Sc 3+ ) presenting in water environments on Mn(VII) activity. These ions uniformly boost the electron and oxygen transfer capabilities of Mn(VII) while impeding proton transfer, as evidenced by electrochemical tests, thioanisole probe analysis, and the kinetic isotope effect. The observed effects are intricately linked to the Lewis acidity of the metal ions. Further mechanistic insights reveal that Mn(VII) can interact with metal ions without direct reduction. Such interactions modify the electronic configuration of Mn(VII) and create an acidic microenvironment, thus increasing its electrophilicity and the energy barrier for the abstraction of proton from organic substrates. More importantly, the efficacy of Mn(VII) in removing phenolic pollutants is regulated by these ions through changing the driving force for proton and electron transfer, i.e., facilitated at pH > 4.5 and inhibited at lower pH. The contribution of active Mn intermediates is also discussed to reveal the oxidative mechanism of the metal ion/Mn(VII) system. These findings not only facilitate the rational design of Mn(VII) oxidation conditions in the presence of metal ions for water decontamination but also offer an alternative paradigm for enhancing electrophilic oxidation.

Reprogramming of cellular metabolism in tumors promoted the epithelial-mesenchymal transition (EMT) process and established immune-suppressive tumor microenvironments (iTME), leading to drug resistance and tumor progression. Therefore, remodeling the cellular metabolism of tumor cells was a promising strategy to overcome drug-resistant tumors. Herein, CD276 and MTHFD2 were identified as a specific marker and a therapeutic target, respectively, for targeting sunitinib-resistant clear cell renal cell carcinoma (ccRCC) and its cancer stem cell (CSC) population. The blockade of MTHFD2 was confirmed to overcome drug resistance via remodeling of folate-nucleotide metabolism. Moreover, the manganese dioxide nanoparticle was proven here by a high-throughput metabolome to be capable of remodeling γ-aminobutyric acid (GABA) metabolism in tumor cells to reconstruct the iTME. Based on these findings, engineered CD276-CD133 dual-targeting biomimetic nanovesicle EMφ-siMTHFD2-MnO 2 @Suni was designed to overcome drug resistance and terminate tumor progression of ccRCC. Using ccRCC-bearing immune-humanized NPG model mice, EMφ-siMTHFD2-MnO 2 @Suni was observed to remodel folate-nucleotide and GABA metabolism to deactivate the EMT process and reconstruct the iTME thereby overcoming the drug resistance. In the incomplete-tumor-resection recurrence model and metastasis model, EMφ-siMTHFD2-MnO 2 @Suni reduced recurrence and metastasis in vivo. This work thus provided an innovative approach that held great potential in the treatment of drug-resistant ccRCC by remodeling cellular metabolism.

This study demonstrates that the oxidation of bromide by birnessite (δ-MnO 2 ) results in the concurrent production of soluble manganese (Mn(II)) and reactive bromine (RBr) species in frozen solutions, a process not observed in aqueous solutions. This enhanced oxidation in ice is attributed to the concentration of protons, birnessite, or bromide in the ice grain boundary region. Furthermore, different types of commercial manganese oxides can also oxidize bromide to RBr and release Mn(II) in ice. The presence of fulvic acid (FA) further increases the simultaneous production of RBr and Mn(II) in ice, accompanying the formation of organobromine compounds (OBCs). In frozen δ-MnO 2 /Br - /FA system, a significant increase in OBCs, mainly highly unsaturated and phenolic compounds, was detected using Fourier transform ion cyclotron resonance mass spectrometry. A marked contrast was observed in the number of OBCs formed in frozen solutions (853 and 415 OBCs at initial pH 3.0 and 5.8, respectively) compared to their aqueous counterparts (11 and 23 OBCs). These findings introduce a new pathway for the formation of RBr, Mn(II), and OBCs in ice, highlighting the need for further research on the environmental fate of bromide and manganese.

A novel immunoassay platform is presented utilizing a cardiac troponin T antibody (Ab-cTnT) labelled with 5-carboxyfluorescein (5-FAM) integrated into a two-dimensional (2D) manganese dioxide nanosheet (MnO 2 NS) matrix. This strategy enables a turn-on response towards cTnT antigen within a mere 10-min incubation period, boasting an impressive lower detection limit of 0.038 ng/mL. Crucially, our probe demonstrates exceptional selectivity amidst the presence of coexisting biomolecules and ions, ensuring precise detection of cTnT. Moreover, the developed platform showcases promising utility in sensing cTnT from spiked human serum samples, yielding satisfactory recovery percentages ranging from 82 to 105%. Additionally, we introduce and easy-to-use and cost-effective test strip for point-of-care detection of cTnT, further enhancing accessibility to critical cardiovascular diagnostics., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

6-mercaptopurine (6-MP) is widely used in the treatment of many diseases, but exhibits some serious side effects due to its toxicity. Therefore, it is important and imperative to effectively control and monitoring concentration of 6-MP. Herein, we designed a smartphone-assisted colorimetric sensing platform for 6-MP detection, based on an excellent β-cyclodextrin modified MnO 2 nanosheets (β-CD@MnO 2 NNS) mediated oxidase-like activity. β-CD@MnO 2 NNS can directly oxidizes 3,3',5,5'-tetramethylbenzidine (TMB) into oxidized TMB with color changes, yielding more than 3-fold higher oxidase-like catalytic activity compared with individual MnO 2 NNS. After adding 6-MP, β-CD@MnO 2 NNS can be reduced to Mn 2+ and lose their oxidase-like properties, resulting in a color and absorbance change for sensitive and selectivity detection of 6-MP. Meanwhile, the smartphone-based color recognition application can intuitively and simply measure the concentration of 6-MP. The limits of detection UV-vis instrument and smartphone were 0.35 μM and 0.86 μM, respectively. This method has also been successfully applied to the detection of real samples. Finally, this study provides a new promising platform for detection of 6-MP and is expected to be used in application of pharmaceutical analysis and biomedicine., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In recent years, the integration of radiotherapy and nanocatalytic medicine has gained widespread attention in the treatment of breast cancer. Herein, the glucose oxidase (GOx) and MnO 2 nanoparticles co-modified multifunctional liposome of GOx-MnO 2 @Lip was constructed for enhanced radiotherapy. Introduction of GOx would not only elevate the glucose consumption to starve the cancer cells, but also increased the endogenous H 2 O 2 level. Meanwhile, high intracellular GSH concentration facilitated the release of Mn 2+ to amplify the cytotoxic ·OH through cascade catalytic reactions within the tumor microenvironment, resulting in a favorable tumor suppression rate of 74.45 %. Furthermore, the blood biochemical and blood routine demonstrated that GOx-MnO 2 @Lip had no obvious toxic side effects. Therefore, this work provided a potential vehicle for synergistic cancer starving therapy, chemodynamic therapy and radiotherapy for improving therapeutic efficacy of breast cancer., Competing Interests: Declaration of Competing Interest The authors declared no conflicts of interest associated with this publication., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Ferroptosis is greatly restricted by low reactive oxygen species (ROS) generation efficiency, and the inherent self-protection mechanism originating in heat shock proteins (HSPs) seriously impedes the efficiency of photothermal therapy (PTT). Herein, we designed an intelligent strategy utilizing cascade catalytic nanoassemblies (Au@COF@MnO 2 ) with triple-enzyme activity for amplifying ferroptosis therapy and improving the efficiency of PTT in tumor. Gold nanozyme was encapsulated within a hollow manganese dioxide (MnO 2 ) shell with the help of covalent organic frameworks (COFs). The nanoassemblies possess the ability of photothermal conversion. Mechanism studies suggested that glutathione (GSH) depletion by Au@COF@MnO 2 leads to the inactivation of glutathione peroxidase 4 (GPX4). This effect synergized with Mn 2+ -mediated reactive oxygen species (ROS) generation to enhance the accumulation of lipid peroxide (LPO), thereby inducing high-efficiency ferroptosis. Notably, gold nanozyme facilitated the conversion of glucose into gluconic acid and hydrogen peroxide (H 2 O 2 ). This process augmented the endogenous H 2 O 2 levels necessary for Fenton chemistry, which could effectively promote the generation of ROS. Simultaneously, glucose depletion downregulated the expression of HSPs induced by hyperthermia, consequently reducing cellular heat resistance for enhancing PTT. Therefore, the cascade catalytic nanoassembly not only exhibits high tumor inhibition and admirable biosafety, but also possesses trimodal imaging performance for imaging-guided tumor therapy in vivo, holding great potential for clinical application. STATEMENT OF SIGNIFICANCE: This study engineered multi-responsive cascade catalytic nanoassembly (Au@COF@MnO 2 ) with triple enzymatic functions for amplifying ferroptosis therapy and improving the efficiency of PTT in tumor. The nanoassembly exhibited multi-responsive release and great photothermal conversion performance. Glucose consumption-evoked starvation downregulated the hyperthermia-induced expression of HSPs in tumor cells, thereby improving the efficacy of PTT. Mechanism studies suggested that GSH depletion by Au@COF@MnO 2 lead to the inactivation of GPX4, which synergized with Mn 2+ -mediated ROS generation to bolster the accumulation of LPO, thereby inducing high-efficiency ferroptosis. Moreover, the nanoassembly demonstrated trimodal (PT, PA, and MR) imaging in vivo, enabling the visualization of the tumor treatment with nanoassembly. Such nanoassembly exhibited high tumor inhibition and admirable biosafety in tumor therapy in vivo, holding a great potential for clinical application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

The highly immunosuppressive tumor microenvironment (TME) restricts the efficient activation of immune responses. To restore the surveillance of the immune system for robust activation, vast efforts are devoted to normalizing the TME. Here, a manganese-doped layered double hydroxide (Mn-LDH) is developed for potent anti-tumor immunity by reversing TME. Mn-LDH is synthesized via a one-step hydrothermal method. In addition to the inherent proton neutralization capacity of LDH, the introduction of manganese oxide endows LDH with an additional ability to produce oxygen. Mn-LDH effectively releases Mn 2+ and Mg 2+ upon exposure to TME with high levels of H + and H 2 O 2 , which activates synthase-stimulator of interferon genes pathway and maintains the cytotoxicity of CD8 + T cells respectively, achieving a cascade-like role in innate and adaptive immunity. The locally administered Mn-LDH facilitated a "hot" network consisting of mature dendritic cells, M1-phenotype macrophages, as well as cytotoxic and helper T cells, significantly inhibiting the growth of primary and distal tumors. Moreover, the photothermal conversion capacity of Mn-LDH sparks more robust therapeutic effects in large established tumor models with a single administration and irradiation. Overall, this study guides the rational design of TME-modulating immunotherapeutics for robust immune activation, providing a clinical candidate for next-generation cancer immunotherapy., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

The hypoxic environment within a solid tumor is a limitation to the effectiveness of photodynamic therapy. Here, we demonstrate the use of oxygen generating nanozymes (CeO 2 , Fe 3 O 4 , and MnO 2 ) to improve the photodynamic effect. The optimized combination of process parameters for irradiation was obtained using the Box Behnken experimental design. Indocyanine green, IR 820, and their different combinations with oxygen generators were studied for their effect on oral carcinoma. Dynamic light scattering technique showed the average particle size of CeO 2 , MnO 2 , and Fe 3 O 4 to be 211 ± 16, and 157 ± 28, 143 ± 19 nm with PDI of 0.23, 0.28 and 0.20 and a zeta potential of -2.6 ± 0.45, -2.4 ± 0.60 and  -6.1 ± 0.23 mV, respectively. The formation of metal oxides was confirmed using UV-visible, FTIR, and X-ray photon spectroscopies. The amount of dissolved oxygen produced by CeO 2 , MnO 2 , and Fe 3 O 4 in the presence of H 2 O 2 within 2 min was 1.7 ± 0.15, 1.7 ± 0.16, and 1.4 ± 0.12 mg/l, respectively. Growth inhibition studies in the FaDu oral carcinoma spheroid model showed a significant (P < 0.05) increase in growth reduction from 81 ± 2.9 and 88 ± 2.1% to 97 ± 1.2 and 99 ± 1.0% for ICG and IR 820, respectively, after irradiation (808 nm laser, 1 W/cm 2 , 5 min) in the presence of CeO 2 (25 μg/ml). In conclusion, oxygen-generating nanozymes can improve the photodynamic effect of ICG and IR 820., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Venkata Vamsi Krishna Venuganti reports financial support was provided by India Ministry of Science & Technology Department of Science and Technology. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Atherosclerosis (AS) is a common cause of coronary heart disease and stroke. The delivery of exogenous H 2 S and in situ production of O 2 within atherosclerotic plaques can help suppress inflammatory cell infiltration and alleviate disease progression. However, the uncontrolled release of gas donors hinders achieving effective drug concentrations and causes toxic effects. Herein, diallyl trisulfide (DATS)-loaded metal-organic cage (MOC)-68-doped MnO 2 nanoparticles are developed as a microenvironment-responsive nanodrug with the capacity for the in situ co-delivery of H 2 S and O 2 to inflammatory cells within plaques. This nanomedicine exhibited excellent monodispersity and stability and protected DATS from degradation in the circulation. In vitro studies showed that the nanomedicine reduced macrophage polarization toward an inflammatory phenotype and inhibited the formation of foam cells, while suppressing the expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and interleukin-1β. In a mouse model of ApoE -/- genotype, the nanomedicine reduces the plaque burden, inflammatory infiltration, and hypoxic conditions within the plaques. Furthermore, the treatment process and therapeutic effects can be monitored by magnetic resonance image (MRI), in real time upon Mn 2+ release from the acidic- and H 2 O 2 - microenvironment-responsive MnO 2 nanoparticles. The DATS-loaded MOC-68-doped MnO 2 -based nanodrug holds great promise as a novel theranostic platform for AS., (© 2024 Wiley‐VCH GmbH.)

The dense extracellular matrix and high interstitial pressure affect the diffusion of nanodrug in tumor tissue, resulting in a small range of action of the active components in nanodrug, thereby affecting its anticancer efficacy. In order to enhance the diffusion ability of nanodrug, a dual-bubble/photothermal-driven nanomissile (HA@MnO 2 @TA/Fe/ICG/TPZ, HMTAFIT) was designed through "four in one" anti-tumor strategy. Harnessing the capabilities of hyaluronic acid, a biomacromolecule, the nanomotor transforms into a nanomissile, targeting cancer cells with precision. The oxygen generated by the reaction of manganese dioxide with hydrogen peroxide and the local temperature rise of indocyanine green under near-infrared light endow HMTAFIT with the ability of bubble/photothermal dual-driven, and the outermost layer of modified hyaluronic acid incubates the targeting properties of HMTAFIT which could avoid damage to normal cells. The bubble/photothermal-dual-driven increases motion speed of HMTAFIT by 13.8 μm/s, and the enhanced "four in one" anti-tumor strategy effectively improved the anticancer efficacy. The precision-guided nanomissile boasts the capability to eliminate deep-seated cancer cells and overcome multidrug resistance via optimized diffusion and a cutting-edge "four-in-one" approach., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The combination of magnetic resonance and fluorescence imaging in dual-modality imaging not only resolves the limitations of conventional single molecular imaging techniques in terms of specificity, sensitivity, and resolution but also expands the possibilities of molecular imaging techniques in diagnostics and therapeutic monitoring. Herein, a novel pH-responsive magnetic resonance/near-infrared fluorescence (MR/NIRF) nanoprobe (MnO 2 @BSA-Cy5.5) was successfully prepared by biomineralizing manganese dioxide (MnO 2 ) with bovine serum albumin (BSA) while coupling fluorescent dye Cy5.5 for precise tumor detection and visualization. The synthesized MnO 2 @BSA-Cy5.5 nanoprobes were spherical particles of approximately 22.62 ± 3.31 nm in size, and their relaxation rates and T 1 imaging signals were activated-enhanced in an acidic environment. Cytotoxicity assay and hematoxylin and eosin staining demonstrated that MnO 2 @BSA-Cy5.5 had low cytotoxicity and good biocompatibility. More importantly, active targeting via solid tumor albumin-binding protein receptor and enhanced permeability and retention effect, the probe can be specifically aggregated to the tumor site of the 8305C tumor model and exhibit excellent MR/NIRF imaging properties. Our results show that MnO 2 @BSA-Cy5.5 has high resolution and sensitivity in tumor imaging and is expected to be applied as an MR/NIRF contrast agent for accurate diagnosis of thyroid cancer., (© 2024 Wiley Periodicals LLC.)

Objective: Glioblastoma multiforme is a highly aggressive form of brain cancer, and early diagnosis plays a pivotal role in improving patient survival rates. In this regard, molecular magnetic resonance imaging has emerged as a promising imaging modality due to its exceptional sensitivity to minute tissue changes and the ability to penetrate deep into the brain. This study aimed to assess the efficacy of a novel contrast agent in detecting gliomas during MRI scans., Materials and Methods: The contrast agent utilized modified chitosan coating on manganese oxide nanoparticles. The modification included adding methotrexate and 5-aminolevulinic acid (MnO 2 /CS@5-ALA-MTX) to target cells with overexpressed folate receptors and breaking down excess hydrogen peroxide in tumor tissue, resulting in enhanced signal intensity in T 1 -weighted MR images but diminished signal intensity in T 2 *-weighted MR images., Results: The nanosystem was characterized and evaluated in MR imaging, safety, and ability to target cells both in vivo and in vitro. MTX-free nanoparticles (MnO 2 /CS@5-ALA NPs) had no obvious cytotoxicity on cell lines U87MG and NIH3T3 after 24/48 h at a concentration of up to 160 µgr/mL (cell viability more than 80%). In this system, methotrexate enables tumor targeting and the MnO 2 /5-ALA improves T 1 -T 2 * -weighted MRI. In addition, MRI scans of mice with M109 carcinoma indicated significant tumor uptake and NP capacity to improve the positive contrast effect., Conclusion: This developed MnO 2 /CS@5-ALA-MTX nanoparticle system may exhibit great potential in the accurate diagnosis of folate receptor over-expressing cancers such as glioblastoma., (© 2024. The Author(s), under exclusive licence to European Society for Magnetic Resonance in Medicine and Biology (ESMRMB).)

A novel laccase mimic enzyme Cu-Mn with excellent photothermal properties was firstly prepared via a combination of hydrothermal and in situ synthesis. Cu-Mn nanozymes could catalyze the typical laccase substrate 2,4-dichlorophenol (2,4-DP) to generate the red quinone imine. Further, loading the MnO 2 nanosheets with photothermal properties, Cu-Mn nanozymes possessed not only excellent laccase catalytic activity, but also high photothermal conversion efficiency. The presence of glutathione S-transferase (GST) recovered the glutathione (GSH)-induced weakness of the laccase activity and photothermal properties of Cu-Mn. Hence, a GST enzyme-regulated dual-mode sensing strategy was established based on Cu-Mn nanozymes. The detection limits of GST monitoring based on colorimetric and photothermal methods were 0.092 and 0.087 U/L with response times of 20 min and 8 min, respectively. Furthermore, the proposed method enabled the measuring of GST levels in human serum and was successfully employed in the primary evaluation of hepatitis patients. Another attraction, the impressive photothermal behavior also endowed the Cu-Mn nanozymes with promising antimicrobial properties, which exhibited significant antimicrobial effects against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus). Unsurprisingly, multifunctional Cu-Mn nanozymes certainly explore new paths in biochemical analysis and antimicrobial applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

There is a growing interest in developing paramagnetic nanoparticles as responsive magnetic resonance imaging (MRI) contrast agents, which feature switchable T 1 image contrast of water protons upon biochemical cues for better discerning diseases. However, performing an MRI is pragmatically limited by its cost and availability. Hence, a facile, routine method for measuring the T 1 contrast is highly desired in early-stage development. This work presents a single-point inversion recovery (IR) nuclear magnetic resonance (NMR) method that can rapidly evaluate T 1 contrast change by employing a single, optimized IR pulse sequence that minimizes water signal for "off-state" nanoparticles and allows for sensitively measuring the signal change with "switch-on" T 1 contrast. Using peptide-induced liposomal gadopentetic acid (Gd 3+ -DTPA) release and redox-sensitive manganese oxide (MnO 2 ) nanoparticles as a demonstration of generality, this method successfully evaluates the T 1 shortening of water protons caused by liposomal Gd 3+ -DTPA release and Mn 2+ formation from MnO 2 reduction. Furthermore, the NMR measurement is highly correlated to T 1 -weighted MRI scans, suggesting its feasibility to predict the MRI results at the same field strength. This NMR method can be a low-cost, time-saving alternative for pre-MRI evaluation for a diversity of responsive T 1 contrast systems., (© 2024 Wiley‐VCH GmbH.)

Manganese (Mn) is a versatile transition element with diverse oxidation states and significant biological importance. Mn-based nanozymes have emerged as promising catalysts in various applications. However, the direct use of manganese oxides as oxidase mimics remains limited and requires further improvement. In this study, we focus on hydroxylated manganese (MnOOH), specifically the layered form β-MnOOH which exhibits unique electronic and structural characteristics. The two-dimensional β-MnOOH nanosheets were synthesized through a hydrothermal approach and showed remarkable oxidase-like activity. These nanosheets effectively converted the oxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), into its oxidized form by initiating the conversion of dissolved oxygen into ·O 2 - , 1 O 2 and ·OH. However, in the presence of L-cysteine (L-Cys), the catalytic activity of β-MnOOH was significantly inhibited, enabling highly sensitive detection of L-Cys. This sensing strategy was successfully applied for smartphone-based L-Cys assay, offering potential utility in the diagnosis of Cys-related diseases. The exploration of layered β-MnOOH nanosheets as highly active oxidase mimics opens up new possibilities for catalytic and biomedical applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Microbial fuel cells (MFCs) can generate electricity by breaking down organic molecules through sustainable bio-electrochemical processes and wastewater as an energy source. A novel approach to remediate wastewater containing selenite was studied utilizing a selenite-reducing mixed bacterial culture with a nano manganese oxide modified cathode in the MFCs. The modification enhanced electrochemical catalytic activity, extracellular electron transfer rate, chemical oxygen demand (COD) elimination efficiency, and coulombic efficiency. Scanning electron microscopy and energy dispersive x-rays analysis were used to examine a manganese dioxide-coated graphite cathode's surface morphology and chemical composition. The manganese dioxide-coated electrode generated up to 69% higher voltage with 150 ppm selenite concentration than the uncoated graphite electrode. The MFC removed up to 80% of the initial COD of 120 mg l -1 and achieved a maximum power density of 1.51 W m -2 . The study demonstrates that MFCs can effectively treat selenite-containing wastewater, and modifying the cathode can enhance energy production., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Damaged skin is susceptible to invasion by harmful microorganisms, especially Staphylococcus aureus and Escherichia coli , which can delay healing. Epigallocatechin-3-gallate (EGCG) is a natural compound known for effectively promoting wound healing and its potent anti-inflammatory effects. However, its application is limited due to its susceptibility to oxidation and isomerization, which alter its structure. The use of zeolitic imidazolate framework-8 (ZIF-8) can effectively tackle these issues. This study introduces an oxygen (O 2 ) and hydrogen peroxide (H 2 O 2 ) self-supplying ZIF-8 nanoplatform designed to enhance the bioavailability of EGCG, combining photodynamic therapy (PDT) and chemodynamic therapy (CDT) to improve antibacterial properties and ultimately accelerate wound healing. For this purpose, EGCG and indocyanine green (ICG), a photosensitizer, were successively integrated into a ZIF-8, and coated with bovine serum albumin (BSA) to enhance biocompatibility. The outer layer of this construct was further modified with manganese dioxide (MnO 2 ) to promote CDT and calcium peroxide (CaO 2 ) to supply H 2 O 2 and O 2 , resulting in the final nanoplatform EGCG-ICG@ZIF-8/BSA-MnO 2 /CaO 2 (EIZBMC). In in vitro experiments under 808 nm laser, EIZBMC exhibited synergistic antibacterial effects through PDT and CDT. This combination effectively released reactive oxygen species (ROS), which mediated oxidative stress to inhibit the bacteria. Subsequently, in a murine model of wound infection, EIZBMC not only exerted antibacterial effects through PDT and CDT but also alleviated the inflammatory condition and promoted the regeneration of collagen fibers, which led to accelerated wound healing. Overall, this research presents a promising approach to enhancing the therapeutic efficacy of EGCG by leveraging the synergistic antibacterial effects of PDT and CDT. This multifunctional nanoplatform maximizes EGCG's anti-inflammatory properties, offering a potent solution for promoting infected wound healing.

Treating bone defect concomitant with microbial infection poses a formidable clinical challenge. Addressing this dilemma necessitates the implementation of biomaterials exhibiting dual capabilities in anti-bacteria and bone regeneration. Of particular significance is the altered microenvironment observed in infected bones, characterized by acidity, inflammation, and an abundance of reactive oxygen species (ROS). These conditions, while challenging, present an opportunity for therapeutic intervention in the context of contaminated bone defects. In this study, we developed an oriented composite scaffold containing copper-coated manganese dioxide (MnO 2 ) nanoparticles loaded with parathyroid hormone (PMPC/Gelatin). The characteristics of these scaffolds were meticulously evaluated and confirmed the high sensitivity to H + , responsive drug release and ROS elimination. In vitro antibacterial analysis underscored the remarkable ability of PMPC/Gelatin scaffolds to substantially suppressed bacterial proliferation and colony formation. Furthermore, this nontoxic material demonstrated efficacy in mitigating ROS levels, thereby fostering osteogenic differentiation of bone marrow mesenchymal stem cells and enhancing angiogenic ability. Subsequently, the infected models of bone defects in rat skulls were established to investigate the effects of composite scaffolds on anti-bacteria and bone formation in vivo. The PMPC/Gelatin treatment exhibited excellent antibacterial activity, coupled with enhanced vascularization and osteogenesis at the defect sites. These compelling findings affirm that the PMPC/Gelatin composite scaffold represents a promising avenue for anti-bacteria and bone regeneration., (© 2024. The Author(s).)

Mercury (Hg) is a hazardous heavy metal, non-biodegradable and toxic, posing a serious threat to aquatic life and human health. Therefore, the removal of Hg ions from contaminated water using effective and eco-friendly adsorbents is necessary. In the present study, three magnetic chitosan-based organic-inorganic nanocomposites, such as CS-MnFe 2 O 4 , CS-MnFe 2 O 4 -CoS, and CS-MnFe 2 O 4 -CoS-MWCNTs, were designed and constructed to investigate their capacity for adsorbing Hg ions from aqueous solutions. The physicochemical properties of prepared composites were characterized by various analyses. The BET analyses indicated their high surface area and porous structure, and the N 2 adsorption-desorption showed that the modification of CS in three stages by MnFe 2 O 4 and crosslinking reaction, CoS preparation, and MWCNT incorporation resulted in increased N 2 adsorption. The XRD confirms the synthesis of MnFe 2 O 4 and CoS in the CS matrix and also the distinct peaks of MWCNTs. The CS-MnFe 2 O 4 -CoS-MWCNTs showed acceptable thermal stability with 45% char yields and superparamagnetic properties with magnetic saturation (Ms) of 16 emu g -1 . The interactive impacts of independent variables (pH, contact time, and adsorbent dosage) on the removal percentage of Hg(II) onto three prepared adsorbents, as well as the process optimization, were assessed by the Box-Behnken design. The optimum conditions were identified, and the data from the analysis of variance showed that the three independent factors (pH, contact time, and adsorbent dosage) significantly influenced the adsorption of Hg(II). The adsorption isotherm and thermodynamics analysis investigation showed that at low concentrations of Hg(II), the adsorption process was both endothermic and spontaneous for the studied adsorbents., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Although the hierarchical manganese dioxide film electrode shows promise as a durable and catalytically active anode for zinc electrowinning, it often fails and deactivates when it is exposed to fluoride-rich environments. The lack of understanding regarding the mechanism behind fluoride-induced irreversible interface reconstruction hinders their practical application in large-scale energy-saving and pollution-reduction efforts. Here, we conducted multidimensional operando investigations to gain insights into the dynamic evolution across the film electrode interface with temporal and spatial resolution. Our findings reveal that electroosmosis of F - initially triggers structural collapse and subsequent reconstruction of [MnO 6 ] units, followed by interaction with the spontaneous oxide film at the surface of lead substrate. Experimental studies and theoretical calculations indicate that F - facilitates the irreversible transformation of γ-MnO 2 into more stable yet protective catalytic dual-defective α-MnO 2 . Additionally, lower levels of F - at the interface promote a change in microenvironmental pH within porous PbSO 4 , triggering the development of microporous corrosion-resistant β-PbO 2 as the dominant phase. The combined effects of MnO 2 and interphase evolution effectively explain the abnormally elevated oxygen evolution overpotential. Then, the proposed appropriate application scenarios based on the corrosion behavior will serve as a practical guide for the implementation of the hierarchical manganese dioxide film electrode.

Development of new technologies with strong selectivity for target pollutants and low sensitivity toward a water matrix remains challenging. Herein, we introduced a novel strategy that used chlorite as an activator for Mn(VII) at pH 4.8, turning the inert reactivity of the pollutants toward Mn(VII) into a strong reactivity. This paved a new way for triggering reactions in water decontamination. By utilizing sulfamethoxazole (SMX) as a typical pollutant, we proposed coupled pathways involving electron transfer across hydrogen bonds (TEHB) and oxidation by reactive manganese species. The results indicated that a hydrogen bonding complex, SMX-ClO 2 - *, formed through chlorite binding the amino group of SMX initially in the TEHB route; such a complex exhibited a stronger reduction capability toward Mn(VII). Chlorite, in the hydrogen bonding complex SMX-ClO 2 - *, can then complex with Mn(VII). Consequently, a new reactive center (SMX-ClO 2 - -Mn(VII)*) was formed, initiating the transfer of electrons across hydrogen bonds and the preliminary degradation of SMX. This is followed by the involvement of the generated Mn(V)-ClO 2 - /Mn(III) in the reduction process of Mn(VII). Such a process showed pH-dependent degradation, with a removal ratio ranging from 80% to near-stagnation as pH increased from 4.8 to 7. Combining with p K a analysis showed that the predominant forms of contaminants were crucial for the removal efficiency of pollutants by the Mn(VII)/chlorite process. The impact of the water matrix was demonstrated to have few adverse or even beneficial effects. With satisfactory performance against numerous contaminants, this study introduced a novel Mn(VII) synergistic strategy, and a new reactivity pattern focused on reducing the reduction potential of the contaminant, as opposed to increasing the oxidation potential of oxidants.

As important organic components in water environments, effluent organic matters (EfOMs) from wastewater treatment plants are widely present in Mn-rich environments or engineered treatment systems. The redox interaction between manganese oxides (MnO x ) and EfOMs can lead to their structural changes, which are crucial for ensuring the safety of water environments. Herein, the reactivities of MnO x with EfOMs were evaluated, and it was found that MnO x with high specific surface area, active high-valent manganese content and lattice oxygen content (i.e., amorphous MnO 2 ) possessed stronger oxidizing ability towards EfOMs. Accompanying by EfOMs oxidation, Mn(IV) and Mn(III) were reduced into Mn(II), with Mn(III) as the significant active species. Through molecular-level transformation analysis by ultrahigh mass spectrometry (FT-ICR MS), the highly reactive compounds in EfOMs were clearly determined to be that with more aromatic and unsaturated structures, especially lignin-like compounds (the highest content in EfOMs (over 60 %)). EfOMs were oxidized by amorphous MnO 2 into products with lower humification index (0.60 vs. 0.46), smaller apparent molecular weight (386.94 Da vs. 368.68 Da), and higher biodegradability (BOD 5 /COD: 0.12 vs. 0.78). This finding suggested that redox reactions between MnO x and EfOMs might alter their abiotic and biotic behaviors in receiving water environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Glyphosate as an effective broad-spectrum herbicide is frequently detected in various water and soil resources. Given the ubiquity of β-MnO 2 and δ-MnO 2 colloids in groundwater and soil, the abiotic removal of glyphosate by MnO 2 colloids was investigated. β-MnO 2 colloids exhibited superior glyphosate removal efficiency, up to 37%, compared to 21% for δ-MnO 2 colloids at a pH of 4.0. Glyphosate removal involved simultaneous adsorption and oxidation process, identified by HRTEM, NH 3 -TPD, XPS, LC-MS, FTIR analyses and the occurrence of aminomethylphosphonic acid (AMPA) and Mn 2+ . Moreover, adsorption dominated the removal of glyphosate by two MnO 2 colloids. The solution pH had a substantial effect on glyphosate removal. Co-existing ions in the solution, such as carbonate (CO 3 2- ), phosphate (Na 2 HPO 4 , NaH 2 PO 4 ) and humic acid (HA), were also found to impede glyphosate removal. Phosphate, in particular, exhibited a strong competitive effect for adsorption sites on both MnO 2 colloids. Of them, the removal of glyphosate by β-MnO 2 colloids was more prone to occur due to its higher specific surface area, abundant oxygen vacancies, and moderate acid sites. However, δ-MnO 2 colloids presented a stronger oxidation capacity than that of β-MnO 2 colloids due to the quicker generation rate of Mn 2+ . Finally, AMPA was the same products by two MnO 2 colloids in the oxidation process, revealing the degradation pathway based on the cleavage of C-N bond. Therefore, by comparing kinetics and mechanisms of glyphosate removal by β- and δ-MnO 2 colloids, this study improves us better understanding for the behavior of glyphosate in the environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Aerobic granular sludge (AGS) is a powerful biotechnological tool capable of treating multiple pollutants simultaneously. However, the granulation process and pollutant removal efficiency still need to be further improved. In this study, Fe 2 O 3 - and MnO 2 -surface-modified straw foam-based AGS (Fe 2 O 3 @SF-AGS and MnO 2 @SF-AGS), with an average particle size of 3 mm, were developed and evaluated. The results showed that surface modification reduced the hydrophobic groups of carriers, facilitating the attachment and proliferation of microorganisms. Notably, MnO 2 @SF-AGS showed excellent granulation performance, reaching a stable state about one week earlier than the unmodified SF-AGS. The polymeric substance content of MnO 2 @SF-AGS was found to be 1.28 times higher than that of the control group. Furthermore, the removal rates for NH 4 + -N, TN, and TP were enhanced by 27.28%, 12.8%, and 32.14%, respectively. The bacterial communities exhibited significant variations in response to different surface modifications of AGS, with genera such as Saprospiraceae, Terrimonas, and Ferruginibacter playing a crucial role in the formation of AGS and the removal of pollutants specifically in MnO 2 @SF-AGS. The charge transfer of metal ions of MnO 2 @SF promotes the granulation process and pollutant removal. These results highlight that MnO 2 @SF-AGS is an effective strategy for improving nitrogen and phosphorus removal efficiency from wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Manganese oxide nanoparticles (MONs)-based contrast agents have attracted increasing attention for magnetic resonance imaging (MRI), attributed to their good biocompatibility and advantageous paramagnetism. However, conventional MONs have poor imaging performance due to low T 1 relaxivity. Additionally, their lack of tumor-targeting theranostics capabilities and complex synthesis pathways have impeded clinical applications. Rutin (Ru) is an ideal tumor-targeted ligand that targets glucose transporters (GLUTs) overexpressed in various malignant tumors, and exhibits photothermal effects upon chelation with metal ions. Herein, a series of Ru-coated MONs (Ru/MnO 2 ) were synthesized using a straightforward, rapid one-step process. Specifically, Ru/MnO 2 -5, with the smallest crystal size of approximately 4 nm, exhibits the highest T 1 relaxivity (33.3 mM -1 s -1 at 1.5 T, surpassing prior MONs) along with notable stability, photothermal efficacy, and tumor-targeting ability. Furthermore, Ru/MnO 2 -5 shows promise in MRI and photothermal therapy of H22 tumors owing to its superior GLUTs-mediated tumor-targeting capability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)