Preparation of UFO-Like Core/Shell Au@MnO₂ Nanoparticles and Their Colorimetric Detection of Glutathione AITranslate

［1］Zhao N，Gong Q，Zhang R X，Yang J，Huang Z Y，Li N，Tang B Z. A fluorescent probe with aggregation-induced emission characteristics for distinguishing homocysteine over cysteine and glutathione［J］.Journal of Materials Chemistry A，2015，3（32）：8397.

［2］Yin J，Kwon Y，Kim D，Lee D，Kim G，Hu Y，Ryu J H，Yoon J. Preparation of a cyanine-based fluorescent probe for highly selective detection of glutathione and its use in living cells and tissues of mice［J］.Nature Protocols，2015，10（11）：1742.

［3］Benhar M，Shytaj I L，Stamler J S，Savarino A J. Dual targeting of the thioredoxin and glutathione systems in cancer and HIV［J］.Journal of Clinical Investigation，2016，126（5）：1630.

［4］Yang P，Ebbert J O，Sun Z，Weinshilboum R M. Role of the glutathione metabolic pathway in lung cancer treatment and prognosis：a review［J］.Journal of Clinical Oncology，2006，24（11）：1761.

［5］Huang M，Wang H，He D，Jiang P，Zhang Y. Ultrafine and monodispersed iridium nanoparticles supported on nitrogen-functionalized carbon：an efficient oxidase mimic for glutathione colorimetric detection［J］.Chemical Communications，2019，55（25）：3634.

［6］（娄语芯，叶仁才，陈坤，钟嘉，毛俐. 中性毛细管电泳电化学发光法检测血清中的同型半胱氨酸和还原型谷胱甘肽［J］.分析试验室，2024，43（8）：1088.）

Y X Lou，R C Ye，K Chen，J Zhong，L Mao. Neutral capillary electrophoresis with electrochemiluminescence sensing for determination of homocysteine and reduced glutathione assay in human serum［J］.Chinese Journal of Analysis Laboratory，2024，43（8）：1088.

［7］Chen J，He Z Y，Liu H，Cha C S. Electrochemical determination of reduced glutathione （GSH） by applying the powder microelectrode technique［J］.Journal of Electroanalytical Chemistry，2006，588（2）：324.

［8］Chen W，Zhao Y，Seefeldt T，Guan X. Determination of thiols and disulfides via HPLC quantification of 5-thio-2-nitrobenzoic acid［J］.Journal of pharmaceutical and biomedical analysis，2008，48（5）：1375.

［9］Zinellu A，Sotgia S，Scanu B，Usai M F，Fois A G，Spada V，Deledda A，Deiana L，Pirina P，Carru C. Simultaneous detection of N-acetyl-l-cysteine and physiological low molecular mass thiols in plasma by capillary electrophoresis［J］.Amino Acids，2009，37（2）：395.

［10］Burford N，Eelman M D，Mahony D E，Morash M. Definitive identification of cysteine and glutathione complexes of bismuth by mass spectrometry：assessing the biochemical fate of bismuth pharmaceutical agents［J］.Chemical Communications，2003，（1）：146.

［11］Li Y X，Li P，Chen Y Q，Wu Y，Wei J.Interfacial deposition of Ag nanozyme on metal-polyphenol nanosphere for SERS detection of cellular glutathione［J］.Biosensors & Bioelectronics，2023，228：115200.

［12］Yang J J，Bian L，Wang A Q，Zhao X F，Arslanov T，Zeng L，Mu B，Song M X，Liu P，Gu X B. Interfacial interactions in CdTe/MX （M=Zn，Cd，Sb，Bi；X=Te，Se，S，O） nanoparticles：implications for glutathione fluorescence detection［J］.ACS Applied Nano Materials，2025，8（35）：17031.

［13］Qi H，Teng M，Liu M，Liu S，Li J，Yu H，Teng C，Huang Z，Liu H，Shao Q. Biomass-derived nitrogen-doped carbon quantum dots：highly selective fluorescent probe for detecting Fe3+ ions and tetracyclines［J］.Journal of Colloid and Interface Science，2019，539：332.

［14］Cai N，Tan L，Li Y，Xia T T，Hu T Y，Su X G. Biosensing platform for the detection of uric acid based on graphene quantum dots and G-quadruplex/hemin DNAzyme［J］.Analytica Chimica Acta，2017，965：96.

［15］（沈潺潺，马骁，李建勋，王海青，裘娜. 三维石墨烯/氧化铜纳米酶在草甘膦检测中的应用究［J］.稀有金属，2022，（8）：846.）

C C Shen，X Ma，J X Li，H Q Wang，N Qiu. Three-dimensional graphene/copper oxide nanocomposites nanozymes for colorimetric sensing of glyphosate［J］.Chinese Journal of Rare Metals，2022，（6）：846.

［16］Liu Q Y，Yang Y T，Li H，Zhu R，Shao Q，Yang S G，Xu J J. NiO nanoparticles modified with 5，10，15，20-tetrakis （4-carboxyl pheyl）-porphyrin：promising peroxidase mimetics for H2O2 and glucose detection［J］.  Biosensors & Bioelectronics，2015，64：147.

［17］Liu Q Y，Yang Y T，Lv X T，Ding Y N，Zhang Y Z，Jing J J，Xu C X. One-step synthesis of uniform nanoparticles of porphyrin functionalized ceria with promising peroxidase mimetics for H2O2 and glucose colorimetric detection［J］.Sensors and Actuators B：Chemical，2017，240：726.

［18］（李静静，梁宽，张泽娜，张海麒，奚红霞，段崇雄. 纳米尺度多级孔金属-有机骨架材料应用研究进展［J］.  稀有金属，2023，47（7）：1013.）

J J Li，K Liang，Z N Zhang，H Q Zhang，H X Xi，C X Duan. Recent advances in application of nanoscale hierarchically porous metal-organic frameworks［J］.Chinese Journal of Rare Metals，2023，47（7）：1013.

［19］Zhang X L，Li G L，Wu D，Li X L，Hu N，Chen J，Chen G，Wu Y N. Recent progress in the design fabrication of metal-organic frameworks-based nanozymes and their applications to sensing and cancer therapy［J］.  Biosensors & Bioelectronics，2019，137：178.

［20］Wang X，Feng S Y，He D P，Jiang P.Porous manganese-cobalt oxide microspheres with tunable oxidase mimicking activity for sulfide ion colorimetric detection［J］.Chemical Communications，2020，56（90）：14098.

［21］Casado A G，Rodriguez L C，Hernandez E A，Vilchez J L. Estimate of gas chromatographic blanks-application to detection limits evaluation as recommended by IUPAC［J］.  Journal of Chromatography A，1996，726（1-2）：133.

［22］Li T，Wang Z，Jiang D，Wang H，Lai W F，Lv Y，Zhai Y. A FRET biosensor based on MnO2 nanosphere/copper nanocluster complex：from photoluminescence quenching to recovery and magnification［J］.Sensors and Actuators B-Chemical，2019，290：535.

［23］Liu Y F，Zhou M，Cao W，Wang X Y，Wang Q，Li S R，Wei H. Light-responsive metal-organic framework as an oxidase mimic for cellular glutathione detection［J］.Analytical Chemistry，2019，91（13）：8170.

［24］Jin C Q，Lian J J，Gao Y，Guo K K，Wu K L，Gao L N，Zhang X X，Zhang X，Liu Q Y. Si doped CoO nanorods as peroxidase mimics for colorimetric sensing of reduced glutathione［J］.Acs Sustainable Chemistry & Engineering，2019，7（16）：13989.

［25］Luo N，Yang Z L，Tang F L，Wang D，Feng M，Liao X J，Yang X P. Fe3O4/carbon nanodot hybrid nanoparticles for the indirect colorimetric detection of glutathione［J］.ACS Applied Nano Materials，2019，2（6）：3951.

［26］Peng C，Xing H H，Fan X S，Xue Y，Li J，Wang E K. Glutathione regulated inner filter effect of MnO2 nanosheets on boron nitride quantum dots for sensitive assay［J］.Analytical Chemistry，2019，91（9）：5762.

［27］Zhu S M，Wang S C，Xia M M，Wang B J，Huang Y，Zhang D X，Zhang X J，Wang G F. Intracellular imaging of glutathione with MnO2 nanosheet@Ru（bpy）32+-UiO-66 nanocomposites［J］.Acs Applied Materials & Interfaces，2019，11（35）：31693.

［28］Sun J Y，Chen N N，Chen X L，Zhang Q，Gao F. Two-photon fluorescent nanoprobe for glutathione sensing and imaging in living cells and zebrafish using a semiconducting polymer dots hybrid with dopamine and β-cyclodextrin［J］.Analytical Chemistry，2019，91（19）：12414.

Basic Information:

DOI：10.13373/j.cnki.cjrm.XY24060009

Chinese Library Classification Number:O657.71

Citation Information:

Glutathione (GSH) exists in all cells and plays a vital role in controlling the redox state of cells. Abnormal GSH concentrations are closely related to many diseases, including AIDS, cancer, liver damage, and diseases caused by aging. Therefore, the development of effective and sensitive GSH detection methods is extremely important. Because of the importance of GSH, its detection methods have emerged endlessly. So far, different methods, such as electroluminescence, surface-enhanced Raman scattering (SERS), mass spectrometry (MS), capillary electrophoresis, high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA), electrochemical, and colorimetric methods have been employed to detect GSH. However, the high price and cumbersome operation limit its practical application. Colorimetric approaches have attracted significant attention due to their rapidity, low cost, and visibility. Mimetic enzyme +3, 3, 5, 5-tetramethylbenzidine (TMB)+H₂O₂ system is one of the most commonly used methods to detect GSH. In the presence of simulated enzyme, including carbon-based nanomateraials, inorganic nanoparticles, and metal-organic frameworks-based nanomaterials, TMB is oxidized by H₂O₂, and the color of the solution changed from colorless to blue. Inspired by the above facts, in this work, well-dispersed Au@MnO₂ nanoparticles were prepared using a simple method. Scanning electron microscope (SEM) image showed that the as-prepared Au@MnO₂ products had structures of the core/shell UFO-like nanoparticles. Line scanning plot suggested Au nanoparticles with an average size of about 50 nm in the center surrounded by the tightly coated layer of MnO₂ with a thickness of 20~30 nm, producing a uniform core-shell structure. Elemental analysis indicated the nanoparticle was composed of elements (Au, Mn, and O). Au@MnO₂ had oxidase-like catalytic activity and could catalyze the oxidation-reduction reaction between TMB and oxygen in the air, resulted in a change in absorbance at 650 nm and a color changed from colorless to blue. In the presence of GSH, GSH reacted with oxidation products (oxTMB) of TMB successfully to inhibit the reaction between MnO₂ and TMB, resulted in the decrease of the absorbance and the lightening of solution color (blue). Under the optimized conditions (pH of 3.6, the reaction time between MnO₂ and TMB：10 min, and incubation time of GSH：5 min), the absorbance of oxTMB at 650 nm wavelength gradually decreased as GSH concentration varies from 0 to 5 μmol·L^-1, accompanied by color changes from dark blue to light blue. Absorbance change (ΔA_{650 nm}), where ΔA was the difference of the absorbance of the solution without and with GSH, was proportional to logarithm of GSH concentration from 1 nmol·L^-1 to 50 μmol·L^-1 (R=0.991). The limit of detection (LOD) reached 0.79 nmol·L^-1 based on signal-to-noise ratio (S/N)=3. Compared with other methods for GSH detection, it was worth noting that the method in this paper was more sensitive for GSH detection, and LOD was lower. The selectivity of Au@MnO₂-TMB reaction system toward other potential interfering antioxidans, including ascorbic acid (AA), cysteine (Cys), tea polyphenols (TP), dopamine (DA), uric acid (UA), citric acid (CA), glucose (Glu), melatonin (Mel), was also investigated. These interfering substances, with 100-time of GSH concentration (5 μmol·L^-1), exhibited very small effect toward the oxTMB absorbance. Compared with the blank absorbance, the absorbance difference values caused by these interferences were in the range of 0.012~0.05. However, GSH, 100 times lower than the concentration of the interfering substances, induced a tremendous change in absorbance compared to the blank, with 0.362 of the absorbance difference value. These results manifested almost no effect of AA, Cys, TP, DA, UA, CA, Glu, and Mel on the GSH detection, and the GSH selectivity for the assay was acceptable. In order to evaluate the feasibility of the assay in complex real samples, GSH in serum was determined. First, serum was diluted 100 times. Then, GSH with a certain content was spiked into the diluted serum samples, so that the final concentration of GSH in serum ranged from 5 nmol·L^-1 to 50 μmol·L^-1. Compared with the GSH detection result in buffer, there was almost no change in absorbance caused by low concentration of GSH (0~1 μmol·L^-1) in serum, and beyond 1 μmol·L^-1, a higher absorbance difference (˂0.223) occurred, meaning the GSH detection of high concentrations influenced by milk media was more serious. However, in view of the good linear relationship between absorbance change and GSH concentration in the range of 5 nmol·L^-1~1 μmol·L^-1 and 1~50 μmol·L^-1, the sensor was suitable for quantitative analysis of GSH in actual samples. In addition, GSH tablets were used to perform the recovery test. The average recovery for GSH tablet (0.1 g) sample was 99.76%~102.1%, which indicated that the method is reliable for GSH detection in real samples.