Ferrioxalate photolysis-assisted green recovery of valuable resources from spent lithium iron phosphate batteries.

Recovering valuable resources from spent cathodes while minimizing secondary waste generation is emerging as an important objective for the future recycling of spent lithium-ion batteries, including lithium iron phosphate (LFP) batteries. This study proposes the use of oxalic acid leaching followed by ferrioxalate photolysis to separate and recover cathode active material elements from spent LFP batteries. The cathode active material can be rapidly dissolved at room temperature using appropriate quantities of oxalic acid and hydrogen peroxide, as determined through thermodynamic calculations. The dissolved ferrioxalate complex ion (Fe(C2O4)33-) is selectively precipitated through subsequent photolysis at room temperature. Depending on the initial concentration, the decomposition ratio can exceed 95 % within 1-4 h. Molecular mechanism analysis reveals that the decomposition of the Fe(C2O4)33- complex ion into water-insoluble FeC2O4·2H2O results in the precipitation of iron and the separation of metal elements. Lithium can be recovered as dihydrogen phosphates through filtration and water evaporation. No additional precipitant is needed and no other side products are generated during the process. Oxalic acid leaching followed by photolysis offers an environmentally friendly and efficient method for metal recovery from spent LFP cathodes. The photochemical process is a promising approach for reducing secondary waste generation in battery recycling.

A universal nanoreactor triggering butterfly effect for encouraging Fenton/Fenton-like reactions and chemodynamic therapy.

Fenton/Fenton-like reaction induced chemical dynamic therapy (CDT) has been widely recognized in tumor therapy. Due to the low efficiency of conversion from high-valent metal ions (M(n+1)+) to low-valent ions (Mn+) in the Fenton/Fenton-like catalytic process, enhancing the conversion efficiency safely and effectively would create a great opportunity for the clinical application of CDT. In the study, a universal nanoreactor (NR) consisting of liposome (Lip), tumor cell membrane (CM), and bis(2,4,5-trichloro-6-carboxyphenyl) oxalate (CPPO) is developed to tackle this challenge. The CPPO was first discovered to decompose under weak acidity and H2O2 conditions to generate carboxylic acids (R'COOH) and alcohols (R'OH) with reducibility, which will reduce M(n+1)+ to Mn+ and magnify the effect of CDT. Furthermore, glucose oxidase (GOx) was introduced to decompose glucose in tumor and generate H2O2 and glucose acid, which promote the degradation of CPPO, further strengthening the efficiency of CDT, leading to a butterfly effect. This demonstrated that the butterfly effect triggered by NR and GOx encourages Fenton/Fenton-like reactions of Fe3O4 and MoS2, thereby enhancing the tumor inhibition effect. The strategy of combining GOx and CPPO to strengthen the Fenton/Fenton-like reaction is a universal strategy, which provides a new and interesting perspective for CPPO in the application of CDT, reflecting the exquisite integration of Fenton chemistry and catalytic medicine.

Mineralization of SF6 and NF3 fluorinated compounds for greenhouse gas abatement by oxalates.

Fluorinated compounds (FCs) such as sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3) have garnered attention due to their environmental impact. This study investigates the mineralization and removal of two potent FCs: SF6 and NF3. The results confirm that utilizing various oxalate salts leads to the formation of corresponding metallic fluorides: lithium fluoride (LiF), sodium fluoride (NaF), and potassium fluoride (KF), validating the occurrence of mineralization reactions. Among the oxalate salts, sodium oxalate demonstrates the highest mineralization efficiency in both SF6 and NF3 removal. Real-time Fourier transform infrared spectroscopy (FT-IR) gas-phase analysis confirms rapid and complete gas removal within a short reaction time using the selected oxalate salts. Meticulous mass balance calculations revealed that oxalates (LiF, NaF, and KF) yielded sulfur (S) at rates of 92.09%, 91.85%, and 84.98% following SF6 mineralization. Additionally, the conversion rates of oxalates to the corresponding metallic fluorides (LiF, NaF, and KF) after SF6 mineralization were 98.18%, 95.82%, and 95.21%, respectively. Similarly, after NF3 mineralization, these conversion rates stood at 92.18%, 90.67%, and 90.02%, respectively. The removal efficiencies for SF6 (1000 ppm) were 4.98, 12.01, and 7.23 L/g, while those for NF3 (1000 ppm) were 14.1, 12.6, and 11.7 L/g, respectively. Notably, sodium oxalate exhibits superior effectiveness, achieving 100% SF6 conversion within 30 min and 100% NF3 conversion within 50 min. This work underscores the potential of oxalate mineralization as a promising strategy for efficient and rapid removal of potent fluorinated compounds, paving the way for environmentally benign FC remediation techniques with broader implications for sustainable gas treatment technologies.

Elucidation of escitalopram oxalate and related antidepressants as putative inhibitors of PTP4A3/PRL-3 protein in hepatocellular carcinoma: A multi-computational investigation.

Hepatocellular carcinoma (HCC) persists to be one of the most devastating and deadliest malignancies globally. Recent research into the molecular signaling networks entailed in many malignancies has given some prominent insights that can be leveraged to create molecular therapeutics for combating HCC. Therefore, in the current communication, an in-silico drug repurposing approach has been employed to target the function of PTP4A3/PRL-3 protein in HCC using antidepressants: Fluoxetine hydrochloride, Citalopram, Amitriptyline, Imipramine, and Escitalopram oxalate as the desired ligands. The density function theory (DFT) and chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) parameters for the chosen ligands were evaluated to comprehend the pharmacokinetics, drug-likeness properties, and bioreactivity of the ligands. The precise interaction mechanism was explored using computational methods such as molecular docking and molecular dynamics (MD) simulation studies to assess the inhibitory effect and the stability of the interactions against the protein of interest. Escitalopram oxalate exhibited a comparatively significant docking score (-7.4 kcal/mol) compared to the control JMS-053 (-6.8 kcal/mol) against the PRL-3 protein. The 2D interaction plots exhibited an array of hydrophobic and hydrogen bond interactions. The findings of the ADMET forecast confirmed that it adheres to Lipinski's rule of five with no violations, and DFT analysis revealed a HOMO-LUMO energy gap of -0.26778 ev, demonstrating better reactivity than the control molecule. The docked complexes were subjected to MD studies (100 ns) showing stable interactions. Considering all the findings, it can be concluded that Escitalopram oxalate and related therapeutics can act as potential pharmacological candidates for targeting the activity of PTP4A3/PRL-3 in HCC.

Solar-assisted oxidation of organochlorine pesticides in groundwater using persulfate and ferrioxalate.

The oxidation of hexachlorocyclohexane isomers in the aqueous phase (Milli-Q and groundwater) was studied using persulfate activated by ferrioxalate and solar light at circumneutral pH. The experiments were conducted in a solar simulator reactor with local radiation fluxes qw= 1.12·10-7 E cm-2s-1 and in compound parabolic collectors with solar light (qw≈10-7 E cm-2s-1) for 390 min. The effect of activator dosage (18-125 µM ferrioxalate) and persulfate concentration (520-2600 µM) on hexachlorocyclohexane conversion and oxalate and oxidant consumption was analyzed. Conversion of about 95% of ß isomer was achieved at 390 min using 1300 µM of initial persulfate and 63 µM of Fe3+ concentration despite this ß isomer being the most recalcitrant to oxidation (XHexachlorocyclohexanes=0.98). Dechlorination above 80% was achieved under these conditions, analyzing the chlorides released into the water. The influence of chloride and bicarbonate on hexachlorocyclohexanes degradation was analyzed in milli-Q water and in groundwater. Hexachlorocyclohexane conversion at 390 min decreases from 98% to 83, 75 and 65% in the presence of chloride, bicarbonate or groundwater, respectively. Results obtained with compound parabolic collectors and solar light using 2600 µM Na2S2O8 and 63 µM Fe for removing hexachlorocyclohexanes agreed with those from the solar simulator reactor, supporting using solar light to activate persulfate for sustainable abatement of persistent organic pollutants in aqueous matrixes.

Stimulation of oxalate root exudate in arsenic speciation and fluctuation with phosphate and iron in anoxic mangrove sediment.

Mutual transformations of rhizospheric arsenic (As) in pollution-prone mangrove sediments affected by root exudate oxalate were simulated. This study focuses on the effect of oxalate on As release, mobilization, and phase speciation associated with P and Fe was examined under anoxic conditions in time-dependent changes. Results showed that oxalate addition significantly facilitated As-Fe-P release from As-contaminated mangrove sediments. Sediment As formed the adsorptive and the carbonate-binding fractionations, facilitating the re-adsorption processes. Solution As and As5+ correlated with NaOH-P positively but with NaHCO3-P and HCl-P negatively. Dominant Fe3+ (>84 %) from the amorphous Fe regulated suspension changes and then time-dependent co-precipitation with As and P. Sediment P formed strong complexes with Fe oxides and could be substituted for As via STEM analysis. Oxalate ligand exchange, competitive adsorption of oxalate, and Fe-reduced dissolution are confirmed to involve, allowing for an insight As/P/Fe mobilization and fate in mangrove wetland.

Highly selective hydrogenation of dimethyl oxalate to methyl glycolate and ethylene glycol over an amino-assisted Ru-based catalyst.

A Ru/NH2-MCM-41 catalyst was prepared via a coordination-assisted strategy for chemoselective hydrogenation of dimethyl oxalate with a high selectivity of methyl glycolate (ca. 100%) and ethylene glycol (>90%) at reaction temperatures of 343 K and 433 K, respectively. The amino groups help to anchor and form stable electron-rich Ru active sites, which accounts for the excellent CO bond activation and hydrogenation selectivity.

Oxalate Activates Autophagy to Induce Ferroptosis of Renal Tubular Epithelial Cells and Participates in the Formation of Kidney Stones.

Renal tubular epithelial cell damage is the basis for the formation of kidney stones. Oxalate can induce human proximal tubular (HK-2) cells to undergo autophagy and ferroptosis. The present study was aimed at investigating whether the ferroptosis of HK-2 cells induced by oxalate is caused by the excessive activation of autophagy. We treated HK-2 cells with 2 mmol/L of oxalate to establish a kidney stone model. First, we tested the degree of oxidative damage and the level of autophagy and ferroptosis in the control group and the oxalate intervention group. We then knocked down and overexpressed the BECN1 gene and knocked down the NCOA4 gene in HK-2 cells, followed by redetection of the above indicators. We confirmed that oxalate could induce autophagy and ferroptosis in HK-2 cells. Moreover, after oxalate treatment, overexpression of the BENC1 gene increased cell oxidative damage and ferroptosis. In addition, knockdown of NCOA4 reversed the effect of oxalate-induced ferroptosis in HK-2 cells. Our results show that the effects of oxalate on the ferroptosis of HK-2 cells are caused by the activation of autophagy, and knockdown of the NCOA4 could ameliorate this effect.

Self-Activatable Photo-Extracellular Vesicle for Synergistic Trimodal Anticancer Therapy.

Extracellular vesicles (EVs) hold great potential in both disease treatment and drug delivery. However, accurate drug release from EVs, as well as the spontaneous treatment effect cooperation of EVs and drugs at target tissues, is still challenging. Here, an engineered self-activatable photo-EV for synergistic trimodal anticancer therapy is reported. M1 macrophage-derived EVs (M1 EVs) are simultaneously loaded with bis[2,4,5-trichloro-6-(pentyloxycarbonyl) phenyl] oxalate (CPPO), chlorin e6 (Ce6), and prodrug aldoxorubicin (Dox-EMCH). After administration, the as-prepared system actively targets tumor cells because of the tumor-homing capability of M1 EVs, wherein M1 EVs repolarize M2 to M1 macrophages, which not only display immunotherapy effects but also produce H2 O2 . The reaction between H2 O2 and CPPO generates chemical energy that activates Ce6, creating both chemiluminescence for imaging and singlet oxygen (1 O2 ) for photodynamic therapy (PDT). Meanwhile, 1 O2 -induced membrane rupture leads to the release of Dox-EMCH, which is then activated and penetrates the deep hypoxic areas of tumors. The synergism of immunotherapy, PDT, and chemotherapy results in potent anticancer efficacy, showing great promise to fight cancers.

Synthetic Methods of Phosphonopeptides.

Phosphonopeptides are phosphorus analogues of peptides and have been widely applied as enzyme inhibitors and antigens to induce catalytic antibodies. Phosphonopeptides generally contain one aminoalkylphosphonic acid residue and include phosphonopeptides with C-terminal aminoalkylphosphonic acids and phosphonopeptides with a phosphonamidate bond. The phosphonamidate bond in the phosphonopeptides is generally formed via phosphonylation with phosphonochloridates, condensation with coupling reagents and enzymes, and phosphinylation followed by oxidation. Pseudo four-component condensation reaction of amides, aldehydes, alkyl dichlorophosphites, and amino/peptide esters is an alternative, convergent, and efficient strategy for synthesis of phosphonopeptides through simultaneous construction of aminoalkylphosphonic acids and formation of the phosphonamidate bond. This review focuses on the synthetic methods of phosphonopeptides containing a phosphonamidate bond.

Photodegradation of para-arsanilic acid mediated by photolysis of iron(III) oxalate complexes.

Organic arsenicals are important environment pollutants due to wide use in livestock and toxicity of degradation products. In this work we report about the efficient photodegradation of the p-arsanilic acid (p-ASA) and its decomposition products in the Fe(III)-oxalate assisted approach under nature-relevant conditions. At neutral pH under near-visible UV irradiation the Fe(III) oxalate complexes generate the primary oxidizing intermediate, OH radical (the quantum yield of ϕOH âˆ¼ 0.06), which rapidly reacts with p-ASA with high rate constant, (8.6 ± 0.5) × 109 M-1s-1. Subsequent radical reactions result in the complete photooxidation of both p-ASA and basic aromatic photoproducts with the predominant formation of inorganic arsenic species, mainly As(V), under optimal conditions. Comparing with the direct UV photolysis, the presented Fe(III)-oxalate mediated degradation of p-ASA has several advantages: higher efficiency at low p-ASA concentration and complete degradation of organic arsenic by-products without use of short-wavelength UV radiation. The obtained results illustrate that the Fe(III)-oxalate complexes are promising natural photosensitizers for the removal of arsenic pollutants from contaminated waters.

NIR-II Chemiluminescence Molecular Sensor for In†Vivo High-Contrast Inflammation Imaging.

Chemiluminescence (CL) sensing without external excitation by light and autofluorescence interference has been applied to high-contrast in vitro immunoassays and in vivo inflammation and tumor microenvironment detection. However, conventional CL sensing usually operates in the range of 400-850 nm, which limits the performance of in vivo imaging due to serious light scattering effects and signal attenuation in tissue. To address this challenge, a new type of CL sensor is presented that functions in the second near-infrared window (NIR-II CLS) with a deep penetration depth (≈8 mm). Successive CL resonance energy transfer (CRET) and Förster resonance energy transfer (FRET) from the activated CL substrate to two rationally designed donor-acceptor-donor fluorophores BTD540 and BBTD700 occurs. NIR-II CLS can be selectively activated by hydrogen peroxide over other reactive oxygen species (ROSs). Moreover, NIR-II CLS is capable of detecting local inflammation in mice with a 4.5-fold higher signal-to-noise ratio (SNR) than that under the NIR-II fluorescence modality.

Development of End Stage Renal Disease after Long-Term Ingestion of Chaga Mushroom: Case Report and Review of Literature.

Chaga mushrooms are widely used in folk remedies and in alternative medicine. Contrary to many beneficial effects, its adverse effect is rarely reported. We here report a case of end-stage renal disease after long-term taking Chaga mushroom. A 49-year-old Korean man with end stage renal disease (ESRD) was transferred to our hospital. Review of kidney biopsy finding was consistent with chronic tubulointerstitial nephritis with oxalate crystal deposits and drug history revealed long-term exposure to Chaga mushroom powder due to intractable atopic dermatitis. We suspected the association between Chaga mushroom and oxalate nephropathy, and measured the oxalate content of remained Chaga mushroom. The Chaga mushroom had extremely high oxalate content (14.2/100 g). Estimated daily oxalate intake of our case was 2 times for four years and 5 times for one year higher than that of usual diet. Chaga mushroom is a potential risk factor of chronic kidney disease considering high oxalate content. Nephrologist should consider oxalate nephropathy in ESRD patients exposed to Chaga mushrooms.

5-Nonyloxytryptamine oxalate-embedded collagen-laminin scaffolds augment functional recovery after spinal cord injury in mice.

Polysialic acid (PSA) is crucial for the induction and maintenance of nervous system plasticity and repair after injury. In order to exploit the immense therapeutic potential of PSA, previous studies have focused on the identification and development of peptide-based or synthetic PSA mimetics. 5-Nonyloxytryptamine (5-NOT) has been previously reported as a PSA-mimicking compound for promoting functional recovery after spinal cord injury in mice. In order to explore the neuroregeneration potential of 5-NOT, the current study was based on a biomaterial approach using collagen-laminin (C/L) scaffolds. In in vitro studies, 5-NOT was observed to promote neurite outgrowth, migration, and fasciculation in cerebellar neuronal cells, whereas in 3D cell cultures it showed more ramification and complex Sholl profiles. 5-NOT promoted the survival and neurite length of cortical neurons when cocultured with glutamate-challenged astrocytes. In in vivo studies, spinal cord compression injury mice were used with immediate application of C/L hydrogels impregnated with 5-NOT. C/L + 5-NOT-treated mice demonstrated ∼75% of motor recovery 14 days after injury. Furthermore, this effect was shown to be dependent on the ERK-MAPK pathway and augmentation of cell survival. Thus, based on a biomaterial approach, our current study provides new insight for 5-NOT-containing hydrogels as a promising candidate to speed up recovery after central nervous system injuries.

Development and Validation of a New Gas Chromatography-Tandem Mass Spectrometry Method for the Measurement of Enrichment of Glyoxylate Metabolism Analytes in Hyperoxaluria Patients Using a Stable Isotope Procedure.

Primary hyperoxalurias (PH) are inborn errors of glyoxylate metabolism characterized by an increase in endogenous oxalate production. Oxalate overproduction may cause calcium-oxalate crystal formation leading to kidney stones, nephrocalcinosis, and ultimately kidney failure. Twenty-four hour urine oxalate excretion is an inaccurate measure for endogenous oxalate production in PH patients and not applicable in those with kidney failure. Treatment efficacy cannot be assessed with this measure during clinical trials. We describe the development and validation of a gas chromatography-tandem mass spectrometry method to analyze the samples obtained following a stable isotope infusion protocol of 13C2-oxalate and 1-13C-glycolate in both healthy individuals and PH patients. Isotopic enrichments of plasma oxalate, glycolate, and glyoxylate were measured on a gas chromatography-triple quadrupole mass spectrometry system using ethylhydroxylamine and N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) for analyte derivatization. Method precision was good for oxalate and glycolate (coefficients of variation [CV] were <6.3% and <4.2% for inter- and intraday precision, respectively) and acceptable for glyoxylate (CV <18.3% and <6.7% for inter- and intraday precision, respectively). The enrichment curves were linear over the specified range. Sensitivity was sufficient to accurately analyze enrichments. This new method allowed calculation of kinetic features of these metabolites, thus enabling a detailed analysis of the various pathways involved in glyoxylate metabolism. The method will further enhance the investigation of the metabolic PH derangements, provides a tool to accurately assess the therapeutic efficacy of new promising therapeutic interventions for PH, and could serve as a clinical tool to improve personalized therapeutic strategies.

Platinum(II)-oxalato complexes of seliciclib (CYC202) derivatives show different cellular effects and lesser adverse effects in mouse lymphoma model than cisplatin.

This work presents a deeper pharmacological evaluation of two formerly prepared and characterized, and highly in vitro cytotoxic platinum(II) oxalato complexes [Pt(ox)(L1)2] (1) and [Pt(ox)(L2)2] (2), containing the derivatives of cyclin-dependent kinase inhibitor (CDKi) seliciclib ((R)-roscovitine, CYC202) coordinating as N-donor carrier ligands, i.e., 2-(1-ethyl-2-hydroxyethylamino)-N6-(4-methoxybenzyl)-9-isopropyladenine (L1) and 2-chloro-N6-(2,4-dimethoxybenzyl)-9-isopropyladenine (L2). The positive results of in vitro cytotoxicity screening on human cancer cell lines (HeLa, HOS, A2780, A2780R, G361 and MCF7 with IC50 at low micromolar levels) published previously, motivated us to perform extended preclinical in vitro experiments to reveal the mechanisms associated with the induction of cancer cell death. In addition, the in vivo antitumor activity was evaluated using the mouse lymphocytic leukaemia L1210 model. The obtained results revealed that complex 1 exceeds the antitumor effect of cisplatin (as for the extension of life-span of mice) and shows far less adverse effects as compared to reference drug cisplatin. The in vitro and ex vivo studies of cellular effects and molecular mechanisms of cell death induction showed that the mechanism of action of complex 1 is essentially different from that of cisplatin. The obtained results showed a possible way how to obtain antitumor active platinum(II) oxalato complexes with better therapeutic profile than contemporary used platinum-based therapeutics.

A triple signal amplification method for chemiluminescent detection of the cancer marker microRNA-21.

Mesoporous silica nanospheres (MSNs) are used in a triple signal amplification chemiluminescent (CL) assay for microRNA-21. It is based on (a) the synergistic amplification via loading and controlled-release of signal reagents by MSNs, (b) target recycling amplification, and (c) the enhancement effect of graphene oxide quantum dots (GOQD). CL is generated by the bis(2,4,6-trichlorophenyl) oxalate (TCPO) and H2O2 reaction in the presence of the fluorophore rhodamine B (RB). RB is firstly loaded into the pores of MSNs modified with amino groupsand coupled with ssDNA. Then, the pores are capped by GOQD. Upon the addition of microRNA-21 into the system, the designed ssDNA assumes a double stranded structure. With the aid of duplex-specific nuclease, the double strand structure is cleaved and the free microRNA-21 enters into the next cycling process to combine with other ssDNA forming double strand structures. After several cycling process, amounts of GOQDs departing from the surface of MSNs cause the opening of the pores of MSNs and the release of RB causes the CL of TCPO-H2O2 reaction system. Free GOQDs can lead to a further CL enhancement. By this method, even a low amount of microRNA-21 leads to a large number of released RB molecules and triggers high-intensity CL. The method was applied in an assay where the CL signal increases linearly with the logarithm of the microRNA-21 concentration in the range of 0.005-50 pmol L-1 and the detection limit is 1.7 fmol L-1 (at 3σ). Graphical abstract Schematic presentation of a triple signal amplification chemiluminescence (CL) analysis platform based on rodamine B (RB) loading and controlled release, target recycling amplification and graphene oxide quantum dots (GOQD) as the enhancer for analysis of microRNA-21 in human serum.

Chemiluminescent liposomes as a theranostic carrier for detection of tumor cells under oxidative stress.

Hydrogen peroxide (H2O2) is one of the main source of oxidative stress and a typical marker of reactive oxygen species (ROS)-associated diseases. Therefore, selective detection and scavenging of overproduced H2O2 provide enormous benefits to the successful treatment of ROS-related diseases. The authors took advantage of this property to detect cancer cells using chemiluminescent peroxyoxalate reaction. Here, a new contrast agent presented for hydrogen peroxide, termed peroxyoxalate liposomes, which detect hydrogen peroxide through chemiluminescence reaction, and have the physical/chemical properties needed for imaging applications. The peroxyoxalate liposomes are composed of Bis (2, 4, 6-trichlorphenyl) oxalate (TCPO) and curcumin as fluorophore. Experimental factors such as TCPO, imidazole, hydrogen peroxide and curcumin concentration were optimized. Moreover, application of curcumin makes it possible to design a system for selective tumor destruction. In the reaction of peroxyoxalate, it acts as an oxalate activator with intracellular hydrogen peroxide and experiences excitation as a result of the reaction. In addition, curcumin also acts as a photosensitizer (PS) causing cell damage. In the optimum conditions, the measurable concentration range of 0.86-220 µM of hydrogen peroxide were evaluated from the linear calibration curve with satisfactory RSD% and corresponding detection limits of 650 nM. Therefore, it has the sensitivity needed to detect physiological concentrations of hydrogen peroxide. Moreover, cellular uptake experiments showed that the liposomes enhance extravasation into permeable membranes and significantly increased the bioavailability of curcumin.

MnO2 nanosheets as the biomimetic oxidase for rapid and sensitive oxalate detection combining with bionic E-eye.

Urolithiasis commonly occurs in kidney and ureteral, and may cause local organ/tissue damage, even kidney failure. The incidence of this disease is increasing worldwide, in which calcium oxalate is the major composition forming the urinary calculus. Therefore, to monitor this disease for the prevention and treatment, measuring the oxalate in the urine is of great significance. Here, a rapid and sensitive colorimetric method was developed based on 3,3',5,5'-tetramethylbenzidine-manganese dioxide (TMB-MnO2) nanosheets for oxalate detection. MnO2 nanosheets acted as an efficient biomimetic oxidase to catalyze the reaction with TMB and oxalate. Pale yellow TMB can be oxidized to blue oxide TMB catalyzed by BSA-stabilized MnO2 nanosheets, and oxalate can selectively inhibit this reaction by consuming and reacting with MnO2 nanosheets, thus achieving the quantitative detection of oxalate. Moreover, a home-made bionic electronic-eye (E-eye) system was developed as a portable in-situ detection platform to efficiently measure the oxalate concentrations in 10 s by direct photographing. By optimizing experimental conditions, this method shows a wide linear range (7.8 µM to 250 µM) and a low detection limit (0.91 µM) for oxalate detection. Besides, this method exhibits high selectivity even with 80-fold interfering chemicals. Furthermore, the performance of the method was validated by testing the artificial urine samples, indicating its great potential for monitoring and diagnosis of urolithiasis in point-of-care applications.