Monitoring biogenic amines,which are metabolic byproducts of shrimp spoilage,is crucial for assessing food quality.Currently,most detection methods for biogenic amines suffer from limitations such as time-consuming pr...Monitoring biogenic amines,which are metabolic byproducts of shrimp spoilage,is crucial for assessing food quality.Currently,most detection methods for biogenic amines suffer from limitations such as time-consuming procedures,complex operations,and delayed results.Colorimetric analysis techniques have gained attention in recent years due to their advantages of short analysis time,simple operation,and suitability for on-site testing.This study successfully developed a series of colorimetric sensor platforms for biogenic amines by loading the natural active ingredient curcumin(CUR)and its derivative of Boron complex BFCUR onto filter paper and electrospun nanofibre films(ENFs),respectively.By analyzing the color response differences of these sensors upon contact with biogenic amines,the colorimetric sensors with superior detection performance were selected and further applied to the visual monitoring and indication of shrimp spoilage processes.展开更多
Simultaneous identification and quantitative detection of phenylenediamine(PDA)isomers,including o-phenylenediamine(OPD),m-phenylenediamine(MPD),and p-phenylenediamine(PPD),are essential for environmental risk assessm...Simultaneous identification and quantitative detection of phenylenediamine(PDA)isomers,including o-phenylenediamine(OPD),m-phenylenediamine(MPD),and p-phenylenediamine(PPD),are essential for environmental risk assessment and human health protection.However,current visual detection methods can only distinguish individual PDA isomers and failed to identify binary or ternary mixtures.Herein,a highly active and ultrastable peroxidase(POD)-like CoPt graphitic nanozyme was used for naked-eye identification and colorimetric/fluorescent(FL)dual-mode quantitative detection of PDA isomers.The CoPt@G nanozyme effectively catalyzed the oxidation of OPD,MPD,PPD,OPD+PPD,OPD+MPD,MPD+PPD and OPD+MPD+PPD into yellow,colorless,lilac,yellow,yellow,wine red and reddish-brown products,respectively,in the presence of H_(2)O_(2).Thus,the MPD,PPD,MPD+PPD and OPD+MPD+PPD were easily identified based on the distinct color of their oxidation products,and the OPD,OPD+PPD,OPD+MPD could be further identified by the additional addition of MPD or PPD.Subsequently,CoPt@G/H_(2)O_(2)-,a 3,3′,5,5′-tetramethylbenzidine(TMB)/CoPt@G/H_(2)O_(2)-,and MPD/CoPt@G/H_(2)O_(2)-enabled colorimetric/FL dual-mode platforms for the quantitative detection of OPD,MPD and PPD were proposed.The experimental results illustrated that the constructed sensing platforms exhibit satisfactory sensitivity,comparable to that reported in previous studies.Finally,the evaluation of PDAs in water samples was realized,yielding satisfactory recoveries.This work expanded the application prospects of nanozymes in assessing environmental risks and protection of human security.展开更多
In this study,a novel colorimetric detection method for tryptophan is developed using Au@MnO_(2)NPs based on their redox reaction.Tryptophan etches the outer MnO_(2)NPs shell and forms a stable protective layer outsid...In this study,a novel colorimetric detection method for tryptophan is developed using Au@MnO_(2)NPs based on their redox reaction.Tryptophan etches the outer MnO_(2)NPs shell and forms a stable protective layer outside the released AuNPs core in situ,accompanied by a noticeable color change from brown to pink.According to the absorbance ratio of 545 nm and 580 nm(A_(545)/A_(580)),a rapid(within 1 min),accurate,and specific detection method for tryptophan is constructed amidst other common amino acids.Coupling with a smartphone application,integrated Au@MnO_(2)NPs-based portable test strips can be used for the point-of-care testing(POCT)of tryptophan.展开更多
Nanomaterials exhibiting mimetic enzyme activity are promising candidates for colorimetric detection of chlorpyrifos.Herein,lignin-based FeN/C nanozymes(FeN/CNs)with peroxidase-like activity were synthesized by a one-...Nanomaterials exhibiting mimetic enzyme activity are promising candidates for colorimetric detection of chlorpyrifos.Herein,lignin-based FeN/C nanozymes(FeN/CNs)with peroxidase-like activity were synthesized by a one-pot method.Within the material,the nitrogen mainly exists as pyrrolyl nitrogen,which coordinates with iron to form an Fe-N structure that serves as the active site.The sensor incorporates acetylcholinesterase(AChE)to facilitate the restoration of oxidized 3,3',5',5'-tetramethylbenzidine(TMB),thereby restoring the blue solution to a color⁃less state.Furthermore,the presence of chlorpyrifos was found to inhibit AChE activity,causing the solution to turn blue again.A sensitive colorimetric method for chlorpyrifos has been established.The linear range of this method for the detection of chlorpyrifos was 0.90-80.00μg·g^(-1) and the limit of detection(LOD)was 0.13μg·g^(-1).When applied to real samples,the method achieved recoveries of 94.4%-109%for chlorpyrifos in soil,and relative standard devia⁃tions(RSD)of the assay were 3.6%-4.2%.Therefore,the constructed sensor holds significant potential for the reli⁃able detection of chlorpyrifos.展开更多
This research has developed a paper-based sensor incorporating molecularly imprinted polymer(MIP)technology for the detection of bisphenol-A(BPA)in plastic bottles.The characterization of BPA-molecular imprinted polym...This research has developed a paper-based sensor incorporating molecularly imprinted polymer(MIP)technology for the detection of bisphenol-A(BPA)in plastic bottles.The characterization of BPA-molecular imprinted polymers on paper(BPA-MIP/FP)demonstrated the successful deposition of MIP on the paper substrate.The binding properties analysis revealed that the BPA-MIP/FP sensor exhibited significantly enhanced BPA adsorption capacity(29.04±1.45μmol/cm^(2))compared to unmodified paper.The sensor demonstrated excellent performance characteristics,including high sensitivity with a detection limit of 0.053 ng/mL and superior selectivity for BPA over other bisphenol compound derivatives.The results of the actual samples showed that the sensor has good stability with a RSD of 3.7%and accuracy with recovery rates in the range from 93.46%to 102.06%.展开更多
Lateral flow immunoassay(LFIA),a rapid detection technique noted for simplicity and economy,has showcased indispensable applicability in diverse domains such as disease screening,food safety,and environmental monitori...Lateral flow immunoassay(LFIA),a rapid detection technique noted for simplicity and economy,has showcased indispensable applicability in diverse domains such as disease screening,food safety,and environmental monitoring.Nevertheless,challenges still exist in detecting ultra-low concentration analytes due to the inherent sensitivity limitations of LFIA.Recently,significant advances have been achieved by integrating enzyme activity probes and transforming LFIA into a highly sensitive tool for rapidly detecting trace analyte concentrations.Specifically,modifying natural enzymes or engineered nanozymes allows them to function as immune probes,directly catalyzing the production of signal molecules or indirectly initiating enzyme activity.Therefore,the signal intensity and detection sensitivity of LFIA are markedly elevated.The present review undertakes a comprehensive examination of pertinent research literature,offering a systematic analysis of recently proposed enzyme-based signal amplification strategies.By way of comparative assessment,the merits and demerits of current approaches are delineated,along with the identification of research avenues that still need to be explored.It is anticipated that this critical overview will garner considerable attention within the biomedical and materials science communities,providing valuable direction and insight toward the advancement of high-performance LFIA technologies.展开更多
A tri-signal ultrasensitive colorimetric/electrochemical detection of ovomucoid(OM)was developed.Herein,copper oxide nanoparticles(CuO NPs)were prepared,which exhibit excellent enzyme-like activity(peroxidase-like and...A tri-signal ultrasensitive colorimetric/electrochemical detection of ovomucoid(OM)was developed.Herein,copper oxide nanoparticles(CuO NPs)were prepared,which exhibit excellent enzyme-like activity(peroxidase-like and laccase-like)and electrochemical activity.CuO@3-APBA nanoparticles(CuO@3-APBA NPs)were prepared by the coordinating Cu with the amino group on 3-aminophenobenic boric acid(3-APBA)in CuO NPs.3-APBA of CuO@3-APBA can react with diol structure on sugar chain of OM under alkaline conditions.Then,a tri-signal ultrasensitive biosensing platform for OM was established based on the catalytic activity of CuO@3-APBA nanozyme.For the first signal,CuO@3-APBA can catalyze oxidation of 1,3,5-trimethylbenzene(TMB)to turn the solution from colorless to blue in the presence of H_(2)O_(2)(absorbance at 652 nm).For the second signal,CuO@3-APBA can catalyze the oxidation of substrates(2,4-dichlorophenol and 4-aminoantipyrine)and turn the solution from colorless to pink(absorbance at 510 nm).For the third signal,electrochemical oxidation peak of copper ion from Cu^(+)to Cu^(2+)of Cu O@3-APBA was recorded by differential pulse voltammetry,which was used to determine the OM.The sensing platform exhibited a wide linear range(0.0000316-100.000000 ng/mL)with a low detection limit(0.0105 pg/mL),as well as showed advantages,such as satisfactory reproducibility,good stability,and excellent selectivity.The assay has the potential applications for ultrasensitive detection of allergen in foods.展开更多
NT build 443, or profile fitting method, is often used to measure the diffusion coefficient of chloride in concrete. However, this method is quite laborious and needs special equipment. Colorimetric method is a quick ...NT build 443, or profile fitting method, is often used to measure the diffusion coefficient of chloride in concrete. However, this method is quite laborious and needs special equipment. Colorimetric method is a quick and simple method to measure the penetration depth of chloride by spraying 0.1 mol/L silver nitrate solution. The objective of this work is to study the possibility of the use of colorimetric method in the calculation of non-steady-state diffusion coefficient. Twelve concrete mixtures with different supplementary cementitious materials and water-to-cement ratios of 0.35, 0.48 and 0.6 were used for study. According to NT build 443, the concrete specimens were immersed in 165 g/L NaC1 （2.8 mol/L） solution for 42 d. Both water-soluble （convert to free chloride） chloride and acid-soluble chloride at different layers of specimens were measured. The results show that the mean value of free chloride concentration at the color change boundary Cd was 0.306 mol/L. The surface free chloride concentration cs was obtained by profile fitting method, which was 40% lower than the chloride concentration of exposure solution after an immersion period of 42 d. Chloride diffusion coefficients obtained by the colorimetric method was not well correlated with those obtained by profile fitting method.展开更多
Accurate on-site determination of arsenic （As） concentration as well as its speciation presents a great environmental challenge especially to developing countries. To meet the need of routine field monitoring, we de...Accurate on-site determination of arsenic （As） concentration as well as its speciation presents a great environmental challenge especially to developing countries. To meet the need of routine field monitoring, we developed a rapid colorimetric method with a wide dynamic detection range and high precision. The novel application of KMnO4 and CHaN2S as effective As（III） oxidant and As（V） reductant, respectively, in the formation of molybdenum blue complexes enabled the differentiation of As（III） and As（V）. The detection limit of the method was 8 ~tg/L with a linear range （R2 = 0.998） of four orders of magnitude in total As concentrations. The As speciation in groundwater samples determined with the colorimetric method in the field were consistent with the results using the high performance liquid chromatography atomic fluorescence spectrometry, as evidenced by a linear correlation in paired analysis with a slope of 0.9990- 0.9997 （p 〈 0.0001, n = 28）. The recovery of 96%-116% for total As, 85%-122% for As（III）, and 88%-127% for As（V） were achieved for groundwater samples with a total As concentration range 100-800 μg/L. The colorimetric result showed that 3.61 g/L As（III） existed as the only As species in a real industrial wastewater, which was in good agreement with the HPLC-AFS result of 3.56 g/L As（Ⅲ）. No interference with the color development was observed in the presence of sulfate, phosphate, silicate, humic acid, and heavy metals from complex water matrix. This accurate, sensitive, and easy-to-use method is especially suitable for field As determination.展开更多
A chemiluminescence enzyme immunoassay based on magnetic microparticles(MmPs-CLEIA)was developed to evaluate serum a-fetoprotein(AFP)in parallel with traditional colorimetric enzyme-linked immunosorbent assay(ELISA).A...A chemiluminescence enzyme immunoassay based on magnetic microparticles(MmPs-CLEIA)was developed to evaluate serum a-fetoprotein(AFP)in parallel with traditional colorimetric enzyme-linked immunosorbent assay(ELISA).A systematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer dosages of immunoreagents,less total assay time,and better linearity,recovery,precision,sensitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results were compared with commercial electrochemiluminescence immunoassay(ECLIA)kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R 20.6703;however,the correlation between MPs-CLEIA and ECLIA(R 20.9582)was obviously better than that between colorimetric ELISA and ECLIA(R 20.6866).展开更多
Metallic nanoparticles have received considerable attention in bioassays and diagnostics due to their unique surface plasmon resonance(SPR) properties.Gold nanoparticles have been employed for the development of SPR-b...Metallic nanoparticles have received considerable attention in bioassays and diagnostics due to their unique surface plasmon resonance(SPR) properties.Gold nanoparticles have been employed for the development of SPR-based colorimetric bioassays.In the present report we have described a sensitive colorimetric approach for estimation of proteins,within a detection limit of 10?80 μg/m L,using unmodified silver nanoparticles.Besides the common advantages of colorimetric assay such as simplicity,high sensitivity,and low cost,our method has a label-free design and provides an important and attractive alternative to classical sensing probes and systems.The present work will contribute to the development of nanotechnology-based diagnostic tools.展开更多
Okadaic acid(OA)is a typical marine toxin with strong toxicity causing diarrheic shellfish poisoning(DSP).Aptamers show great advantages in toxin detection and attract increasing attentions in the field of food analys...Okadaic acid(OA)is a typical marine toxin with strong toxicity causing diarrheic shellfish poisoning(DSP).Aptamers show great advantages in toxin detection and attract increasing attentions in the field of food analysis.In this study,a label-free col-orimetric aptasensor was constructed for visual and rapid detection of OA in shellfish.To exploit the binding capability of the anti-OA aptamer,the inherent molecular recognition mechanism of aptamer and OA was studied,based on molecular docking,fluorescent assay,and biolayer interferometry.Consistent results showed that the stem-loop near the 3’terminal of the aptamer exhibit dominate binding capacity.Based on the revealed recognition information,the aptamer was thus rationally utilized and combined with AuNPs and cationic polymer polydiallyl dimethyl ammonium chloride(PDDA)for the development of the label-free colorimetric aptasensor,in which the 3’terminal was thoroughly exposed to OA.The aptasensor provided robust performance with a linear detection range of 100-1200 nmol L-1,a limit of detection of 41.30 nmol L-1,recovery rates of 91.6%-106.2%,as well as a high selectivity towards OA in shellfish samples.The whole detection process can be completed within 1 h.To our best knowledge,this is the first time that the anti-OA aptamer was thoroughly studied,and a label-free colorimetric aptasensor was rationally designed in this way.This study not only provides a rapid detection method for highly sensitive and specific detection of OA,but also serves as a reference for the design of efficient aptasensors in the future.展开更多
Colorimetric characterization is to transform the device-dependent responses to device-independent colorimetric values, and is usually conducted in CIEXYZ space. However, the optimal solution in CIEXYZ space does not ...Colorimetric characterization is to transform the device-dependent responses to device-independent colorimetric values, and is usually conducted in CIEXYZ space. However, the optimal solution in CIEXYZ space does not mean the mini-mization of perceptual error. A novel method for colorimetric characterization of imaging device based on the minimization of total color difference is proposed. The method builds the transform between RGB space and CIELAB space directly using the downhill simplex algorithm. Experimental results showed that the proposed method performs better than traditional least-square (LS) and total-least-square (TLS) methods, especially for colors with low luminance values.展开更多
Iron chalcogenides have attracted great interest as potential substitutes of nature enzymes in the colorimetric biological sensing due to their unique chemodynamic characteristics.Herein,we report the preparation of u...Iron chalcogenides have attracted great interest as potential substitutes of nature enzymes in the colorimetric biological sensing due to their unique chemodynamic characteristics.Herein,we report the preparation of ultrathin Fe S nanosheets(NSs)by a simple one-pot hydrothermal method and the prepared Fe S NSs exhibit strong Fenton-reaction activity to catalyze hydrogen peroxide(H_(2)O_(2))for generation of hydroxyl radical(^(·)OH).Based on the chromogenic reaction of resultant^(·)OH with 3,3,5,5-tetramethylbenzidine(TMB),we develop colorimetric biosensors for highly sensitive detection of H_(2)O_(2)and glutathione(GSH).The fabricated biosensors show wide linear ranges for the detection of H_(2)O_(2)(5–150μmol/L)and GSH(5–50μmol/L).Their detection limits for H_(2)O_(2)and GSH reach as low as0.19μmol/L and 0.14μmol/L,respectively.The experimental results of sensing intracellular H_(2)O_(2)and GSH demonstrate that this colorimetric method can realize the accurate detection of H_(2)O_(2)and GSH in normal cells(L02 and 3T3)and cancer cells(MCF-7 and He La).Our results have demonstrated that the synthesized Fe S NSs is a promising material to construct colorimetric biosensors for the sensitive detection of H_(2)O_(2)and GSH,holding great promising for medical diagnosis in cancer therapy.展开更多
The development of efficient methods for the detection of hazardous and toxic elements is extremely important for environmental security and public health.In this work,we developed a facile colorimetric assaying syste...The development of efficient methods for the detection of hazardous and toxic elements is extremely important for environmental security and public health.In this work,we developed a facile colorimetric assaying system for Ag+detection in aqueous solution.Chitosan-stabilized platinum nanoparticles(ChPtNPs)were synthesized and severed as an artificial oxidase to catalyze the oxidation of the substrate3,30,5,50-tetramethylbenzidine(TMB)and generate color signal.In the presence of Ag+,due to the strong metallophilic interactions between Ag+and Pt^(2+)on the surface of Ch-PtNPs,Ag^(+)can weaken the affinity to the substrates and inactivate the catalytic activity of Ch-PtNPs,leading to decreased absorbance signal to varying degrees depending on Ag+amount.Combing the specific binding between Ch-PtNPs and Ag+with signal amplification procedure based on the Ch-PtNPs-catalyzed TMB oxidation,a sensitive,selective,simple,cost-effective,and rapid detection method for Ag+can be realized.Ag+ions in tap and lake waters have been successfully detected.We ensured that the proposed method can be a potential alternative for Ag+determination in environmental samples.展开更多
Due to the serious harm of diabetes to human health,development of sensitive assays for glucose level is of high significance for early prevention and treatment of diabetes.Currently,most conventional enzyme-based glu...Due to the serious harm of diabetes to human health,development of sensitive assays for glucose level is of high significance for early prevention and treatment of diabetes.Currently,most conventional enzyme-based glucose sensors suffer from high cost and low stability due to the inherent defects of natural enzymes.Herein,we develop a pure nanozyme-based glucose detection method using Ag@Au core/shell triangular nanoplates(TNPs),which combines glucose oxidase(GOD)-and horseradish peroxidase(HRP)-like activities of the Au shell and inherent plasmonic properties of Ag TNPs.The sensing mechanism is based on the fact that the Au shell possessed GOD-like activity,enabling the oxidation of glucose to produce H2O2,which can further etch the silver core,leading to the decrease of absorbance at 800 nm and the color change from blue to colorless.Compared with the previous nanozymes-based glucose sensors,our method avoids the use of enzymes and organic chromogenic agent.Moreover,the stability of the Ag@Au core/shell TNPs is much better than that of Ag TNPs due to the protection by the coating of the Au shell.This method was successfully applied to the detection of urine samples from patients with diabetes,indicating its practical applicability for real sample analysis.展开更多
The objective of this study is to propose a more accurate and faster MTT 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins...The objective of this study is to propose a more accurate and faster MTT 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r2=0.975±0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125～32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7～8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24～28 h for ADA. The MCA provides an accurate and rapid method for quantifi-cation of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.展开更多
Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption, but other ...Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption, but other 19 kinds of natural amino acids could not. Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.展开更多
Norovirus(NoV)is regarded as one of the most common causes of foodborne diarrhea in the world.It is urgent to identify the pathogenic microorganism of the diarrhea in short time.In this work,we developed an electroche...Norovirus(NoV)is regarded as one of the most common causes of foodborne diarrhea in the world.It is urgent to identify the pathogenic microorganism of the diarrhea in short time.In this work,we developed an electrochemical and colorimetric dual-mode detection for NoV based on the excellent dual catalytic properties of copper peroxide/COF-NH_(2)nanocomposite(CuO_(2)@COF-NH_(2)).For the colorimetric detection,NoV can be directly detected by the naked eye based on CuO_(2)@COF-NH_(2)as a laccase-like nonazyme using“peptide-NoV-antibody”recognition mode.The colorimetric assay displayed a wide and quality linear detection range from 1 copy/mL to 5000 copies/mL of NoV with a low limit of detection(LOD)of 0.125 copy/mL.For the electrochemical detection of NoV,CuO_(2)@COF-NH_(2)showed an oxidation peak of copper ion from Cu^(+)to Cu^(2+)using“peptide-NoV-antibody”recognition mode.The electrochemical assay showed a linear detection range was 1-5000 copies/mL with a LOD of 0.152 copy/mL.It's worthy to note that this assay does not need other electrical signal molecule,which provide the stable and sensitive electrochemial detection for NoV.The electrochemical and colorimetric dual-mode detection was used to detect NoV in foods and faceal samples,which has the potential for improving food safety and diagnosing of NoV-infected diarrhea.展开更多
A rhodamine-based sensor has been developed for the detection of mercuric ions. The colorimetric and fluorescence responses, allowing naked-eye detections, are based on Hg^2＋-induced opening of the rhodamine spirocyc...A rhodamine-based sensor has been developed for the detection of mercuric ions. The colorimetric and fluorescence responses, allowing naked-eye detections, are based on Hg^2＋-induced opening of the rhodamine spirocycle. Among all the testes ions, only Hg^2＋generated a significant fluorescence enhancement of up to 300-fold, with a bright yellow–green emission. This sensor was a low toxic compound, and was successfully applied in the in vivo imaging of Hg^2＋in Spill 2 cells and C. elegans. This approach provides a sensitive and accurate method for the estimation of Hg^2＋in environmental, tobacco and biological applications.展开更多
基金Supported by the Guangdong-Hong Kong-Macao Joint Laboratory on Micro-Nano Manufacturing Technology,China(No.2021LSYS004)Guangdong Provincial Key Laboratory of Sustainable Biomimetic Materials and Green Energy,China(No.2024B1212010003)。
文摘Monitoring biogenic amines,which are metabolic byproducts of shrimp spoilage,is crucial for assessing food quality.Currently,most detection methods for biogenic amines suffer from limitations such as time-consuming procedures,complex operations,and delayed results.Colorimetric analysis techniques have gained attention in recent years due to their advantages of short analysis time,simple operation,and suitability for on-site testing.This study successfully developed a series of colorimetric sensor platforms for biogenic amines by loading the natural active ingredient curcumin(CUR)and its derivative of Boron complex BFCUR onto filter paper and electrospun nanofibre films(ENFs),respectively.By analyzing the color response differences of these sensors upon contact with biogenic amines,the colorimetric sensors with superior detection performance were selected and further applied to the visual monitoring and indication of shrimp spoilage processes.
基金supported by the National Key Research and Development Program of China(No.2022YFC2403500)the National Natural Science Foundation of China(No.22225401)+1 种基金the Science and Technology Innovation Program of Hunan Province(No.2020RC4017)the Guizhou Provincial Science and Technology Projects(No.ZK[2023]293).
文摘Simultaneous identification and quantitative detection of phenylenediamine(PDA)isomers,including o-phenylenediamine(OPD),m-phenylenediamine(MPD),and p-phenylenediamine(PPD),are essential for environmental risk assessment and human health protection.However,current visual detection methods can only distinguish individual PDA isomers and failed to identify binary or ternary mixtures.Herein,a highly active and ultrastable peroxidase(POD)-like CoPt graphitic nanozyme was used for naked-eye identification and colorimetric/fluorescent(FL)dual-mode quantitative detection of PDA isomers.The CoPt@G nanozyme effectively catalyzed the oxidation of OPD,MPD,PPD,OPD+PPD,OPD+MPD,MPD+PPD and OPD+MPD+PPD into yellow,colorless,lilac,yellow,yellow,wine red and reddish-brown products,respectively,in the presence of H_(2)O_(2).Thus,the MPD,PPD,MPD+PPD and OPD+MPD+PPD were easily identified based on the distinct color of their oxidation products,and the OPD,OPD+PPD,OPD+MPD could be further identified by the additional addition of MPD or PPD.Subsequently,CoPt@G/H_(2)O_(2)-,a 3,3′,5,5′-tetramethylbenzidine(TMB)/CoPt@G/H_(2)O_(2)-,and MPD/CoPt@G/H_(2)O_(2)-enabled colorimetric/FL dual-mode platforms for the quantitative detection of OPD,MPD and PPD were proposed.The experimental results illustrated that the constructed sensing platforms exhibit satisfactory sensitivity,comparable to that reported in previous studies.Finally,the evaluation of PDAs in water samples was realized,yielding satisfactory recoveries.This work expanded the application prospects of nanozymes in assessing environmental risks and protection of human security.
基金College student innovation training program of Guangzhou University,202311078018the National Key Research and Development Program of China,2022YFE0201800+2 种基金Fundamental Research Funds for the Central Universities,24xkjc025Tertiary Education Scientific research project of Guangzhou Municipal Education Bureau,2024312227Guangzhou University Instrument and Equipment Open Sharing Fund,Year 2024。
文摘In this study,a novel colorimetric detection method for tryptophan is developed using Au@MnO_(2)NPs based on their redox reaction.Tryptophan etches the outer MnO_(2)NPs shell and forms a stable protective layer outside the released AuNPs core in situ,accompanied by a noticeable color change from brown to pink.According to the absorbance ratio of 545 nm and 580 nm(A_(545)/A_(580)),a rapid(within 1 min),accurate,and specific detection method for tryptophan is constructed amidst other common amino acids.Coupling with a smartphone application,integrated Au@MnO_(2)NPs-based portable test strips can be used for the point-of-care testing(POCT)of tryptophan.
基金The Fundamental Research Funds for the Central Universities(2572022DJ01)Natural Science Foundation of Heilongjiang Province(LH2022B002)。
文摘Nanomaterials exhibiting mimetic enzyme activity are promising candidates for colorimetric detection of chlorpyrifos.Herein,lignin-based FeN/C nanozymes(FeN/CNs)with peroxidase-like activity were synthesized by a one-pot method.Within the material,the nitrogen mainly exists as pyrrolyl nitrogen,which coordinates with iron to form an Fe-N structure that serves as the active site.The sensor incorporates acetylcholinesterase(AChE)to facilitate the restoration of oxidized 3,3',5',5'-tetramethylbenzidine(TMB),thereby restoring the blue solution to a color⁃less state.Furthermore,the presence of chlorpyrifos was found to inhibit AChE activity,causing the solution to turn blue again.A sensitive colorimetric method for chlorpyrifos has been established.The linear range of this method for the detection of chlorpyrifos was 0.90-80.00μg·g^(-1) and the limit of detection(LOD)was 0.13μg·g^(-1).When applied to real samples,the method achieved recoveries of 94.4%-109%for chlorpyrifos in soil,and relative standard devia⁃tions(RSD)of the assay were 3.6%-4.2%.Therefore,the constructed sensor holds significant potential for the reli⁃able detection of chlorpyrifos.
基金provided by the Faculty of Mathematics and Natural Science, Universitas Islam Indonesia through Grant Number 323/Dek-FMIPA/70/FMIPAIV/2024。
文摘This research has developed a paper-based sensor incorporating molecularly imprinted polymer(MIP)technology for the detection of bisphenol-A(BPA)in plastic bottles.The characterization of BPA-molecular imprinted polymers on paper(BPA-MIP/FP)demonstrated the successful deposition of MIP on the paper substrate.The binding properties analysis revealed that the BPA-MIP/FP sensor exhibited significantly enhanced BPA adsorption capacity(29.04±1.45μmol/cm^(2))compared to unmodified paper.The sensor demonstrated excellent performance characteristics,including high sensitivity with a detection limit of 0.053 ng/mL and superior selectivity for BPA over other bisphenol compound derivatives.The results of the actual samples showed that the sensor has good stability with a RSD of 3.7%and accuracy with recovery rates in the range from 93.46%to 102.06%.
基金Financial supports from the National Natural Science Foundation of China(NSFC,Nos.52272144 and 22205048)Heilongjiang Provincial Natural Science Foundation of China(No.JQ2022E001)+3 种基金China Postdoctoral Science Foundation(Nos.2022M710931 and 2023T160154)Heilongjiang Postdoctoral Science Foundation(No.LBH-Z22010)Natural Science Foundation of Shandong Province(No.ZR2020ZD42)the Fundamental Research funds for the Central Universities are greatly acknowledged.
文摘Lateral flow immunoassay(LFIA),a rapid detection technique noted for simplicity and economy,has showcased indispensable applicability in diverse domains such as disease screening,food safety,and environmental monitoring.Nevertheless,challenges still exist in detecting ultra-low concentration analytes due to the inherent sensitivity limitations of LFIA.Recently,significant advances have been achieved by integrating enzyme activity probes and transforming LFIA into a highly sensitive tool for rapidly detecting trace analyte concentrations.Specifically,modifying natural enzymes or engineered nanozymes allows them to function as immune probes,directly catalyzing the production of signal molecules or indirectly initiating enzyme activity.Therefore,the signal intensity and detection sensitivity of LFIA are markedly elevated.The present review undertakes a comprehensive examination of pertinent research literature,offering a systematic analysis of recently proposed enzyme-based signal amplification strategies.By way of comparative assessment,the merits and demerits of current approaches are delineated,along with the identification of research avenues that still need to be explored.It is anticipated that this critical overview will garner considerable attention within the biomedical and materials science communities,providing valuable direction and insight toward the advancement of high-performance LFIA technologies.
基金financially supported by Major Science and Technology Project of Yunnan Province(202302AE090022)the National Natural Science Foundation of China(21764005,32160236)+4 种基金National Key Research and Development Program of China(2022YFC2601604)Spring City Plan:the High-level Talent Promotion and Training Project of Kunming(2022SCP001)the Second Phase of“Double-First Class”Program Construction of Yunnan UniversityProgram for Donglu Scholars of Yunnan Universitythe Research Innovation Fund for Graduate Students of School of Chemical Science and Technology,Yunnan University。
文摘A tri-signal ultrasensitive colorimetric/electrochemical detection of ovomucoid(OM)was developed.Herein,copper oxide nanoparticles(CuO NPs)were prepared,which exhibit excellent enzyme-like activity(peroxidase-like and laccase-like)and electrochemical activity.CuO@3-APBA nanoparticles(CuO@3-APBA NPs)were prepared by the coordinating Cu with the amino group on 3-aminophenobenic boric acid(3-APBA)in CuO NPs.3-APBA of CuO@3-APBA can react with diol structure on sugar chain of OM under alkaline conditions.Then,a tri-signal ultrasensitive biosensing platform for OM was established based on the catalytic activity of CuO@3-APBA nanozyme.For the first signal,CuO@3-APBA can catalyze oxidation of 1,3,5-trimethylbenzene(TMB)to turn the solution from colorless to blue in the presence of H_(2)O_(2)(absorbance at 652 nm).For the second signal,CuO@3-APBA can catalyze the oxidation of substrates(2,4-dichlorophenol and 4-aminoantipyrine)and turn the solution from colorless to pink(absorbance at 510 nm).For the third signal,electrochemical oxidation peak of copper ion from Cu^(+)to Cu^(2+)of Cu O@3-APBA was recorded by differential pulse voltammetry,which was used to determine the OM.The sensing platform exhibited a wide linear range(0.0000316-100.000000 ng/mL)with a low detection limit(0.0105 pg/mL),as well as showed advantages,such as satisfactory reproducibility,good stability,and excellent selectivity.The assay has the potential applications for ultrasensitive detection of allergen in foods.
基金Project(2010QZZD018) supported by Central South Universtiy,China,and Ghent University,Belgium
文摘NT build 443, or profile fitting method, is often used to measure the diffusion coefficient of chloride in concrete. However, this method is quite laborious and needs special equipment. Colorimetric method is a quick and simple method to measure the penetration depth of chloride by spraying 0.1 mol/L silver nitrate solution. The objective of this work is to study the possibility of the use of colorimetric method in the calculation of non-steady-state diffusion coefficient. Twelve concrete mixtures with different supplementary cementitious materials and water-to-cement ratios of 0.35, 0.48 and 0.6 were used for study. According to NT build 443, the concrete specimens were immersed in 165 g/L NaC1 （2.8 mol/L） solution for 42 d. Both water-soluble （convert to free chloride） chloride and acid-soluble chloride at different layers of specimens were measured. The results show that the mean value of free chloride concentration at the color change boundary Cd was 0.306 mol/L. The surface free chloride concentration cs was obtained by profile fitting method, which was 40% lower than the chloride concentration of exposure solution after an immersion period of 42 d. Chloride diffusion coefficients obtained by the colorimetric method was not well correlated with those obtained by profile fitting method.
基金the financial support of the National Natural Science Foundation of China (No. 20977098,20921063)the National Basic Research Program (973) of China (No. 2010CB933502)
文摘Accurate on-site determination of arsenic （As） concentration as well as its speciation presents a great environmental challenge especially to developing countries. To meet the need of routine field monitoring, we developed a rapid colorimetric method with a wide dynamic detection range and high precision. The novel application of KMnO4 and CHaN2S as effective As（III） oxidant and As（V） reductant, respectively, in the formation of molybdenum blue complexes enabled the differentiation of As（III） and As（V）. The detection limit of the method was 8 ~tg/L with a linear range （R2 = 0.998） of four orders of magnitude in total As concentrations. The As speciation in groundwater samples determined with the colorimetric method in the field were consistent with the results using the high performance liquid chromatography atomic fluorescence spectrometry, as evidenced by a linear correlation in paired analysis with a slope of 0.9990- 0.9997 （p 〈 0.0001, n = 28）. The recovery of 96%-116% for total As, 85%-122% for As（III）, and 88%-127% for As（V） were achieved for groundwater samples with a total As concentration range 100-800 μg/L. The colorimetric result showed that 3.61 g/L As（III） existed as the only As species in a real industrial wastewater, which was in good agreement with the HPLC-AFS result of 3.56 g/L As（Ⅲ）. No interference with the color development was observed in the presence of sulfate, phosphate, silicate, humic acid, and heavy metals from complex water matrix. This accurate, sensitive, and easy-to-use method is especially suitable for field As determination.
基金supported by the National Basic Research Program of China(973 Program,no.2007CB714507)National Nature Science Foundation of China(no.90813015)
文摘A chemiluminescence enzyme immunoassay based on magnetic microparticles(MmPs-CLEIA)was developed to evaluate serum a-fetoprotein(AFP)in parallel with traditional colorimetric enzyme-linked immunosorbent assay(ELISA).A systematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer dosages of immunoreagents,less total assay time,and better linearity,recovery,precision,sensitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results were compared with commercial electrochemiluminescence immunoassay(ECLIA)kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R 20.6703;however,the correlation between MPs-CLEIA and ECLIA(R 20.9582)was obviously better than that between colorimetric ELISA and ECLIA(R 20.6866).
基金Grants received by D. Dash from the Department of Biotechnology (DBT),Government of India,and Indian Council of Medical Research (ICMR),and equipment supports from the DST Unit on Nanoscience and Technology (DST-UNANST),Banaras Hindu University,and Humboldt Foundation
文摘Metallic nanoparticles have received considerable attention in bioassays and diagnostics due to their unique surface plasmon resonance(SPR) properties.Gold nanoparticles have been employed for the development of SPR-based colorimetric bioassays.In the present report we have described a sensitive colorimetric approach for estimation of proteins,within a detection limit of 10?80 μg/m L,using unmodified silver nanoparticles.Besides the common advantages of colorimetric assay such as simplicity,high sensitivity,and low cost,our method has a label-free design and provides an important and attractive alternative to classical sensing probes and systems.The present work will contribute to the development of nanotechnology-based diagnostic tools.
基金funded by the National Natural Sci-ence Foundation of China(No.31801620).
文摘Okadaic acid(OA)is a typical marine toxin with strong toxicity causing diarrheic shellfish poisoning(DSP).Aptamers show great advantages in toxin detection and attract increasing attentions in the field of food analysis.In this study,a label-free col-orimetric aptasensor was constructed for visual and rapid detection of OA in shellfish.To exploit the binding capability of the anti-OA aptamer,the inherent molecular recognition mechanism of aptamer and OA was studied,based on molecular docking,fluorescent assay,and biolayer interferometry.Consistent results showed that the stem-loop near the 3’terminal of the aptamer exhibit dominate binding capacity.Based on the revealed recognition information,the aptamer was thus rationally utilized and combined with AuNPs and cationic polymer polydiallyl dimethyl ammonium chloride(PDDA)for the development of the label-free colorimetric aptasensor,in which the 3’terminal was thoroughly exposed to OA.The aptasensor provided robust performance with a linear detection range of 100-1200 nmol L-1,a limit of detection of 41.30 nmol L-1,recovery rates of 91.6%-106.2%,as well as a high selectivity towards OA in shellfish samples.The whole detection process can be completed within 1 h.To our best knowledge,this is the first time that the anti-OA aptamer was thoroughly studied,and a label-free colorimetric aptasensor was rationally designed in this way.This study not only provides a rapid detection method for highly sensitive and specific detection of OA,but also serves as a reference for the design of efficient aptasensors in the future.
文摘Colorimetric characterization is to transform the device-dependent responses to device-independent colorimetric values, and is usually conducted in CIEXYZ space. However, the optimal solution in CIEXYZ space does not mean the mini-mization of perceptual error. A novel method for colorimetric characterization of imaging device based on the minimization of total color difference is proposed. The method builds the transform between RGB space and CIELAB space directly using the downhill simplex algorithm. Experimental results showed that the proposed method performs better than traditional least-square (LS) and total-least-square (TLS) methods, especially for colors with low luminance values.
基金the Key Grant for Special Professors in Jiangsu Province(No.RK030STP18001)the National Postdoctoral Program for Innovative Talents(No.BX20190156)+1 种基金the China Postdocoral Science Foundation funded project(No.2021M691654)the“1311 Talents Program”of Nanjing University of Posts and Telecommunications,the Scientific Research Foundation of Nanjing University of Posts and Telecommunications(Nos.NY218150,NY221042)。
文摘Iron chalcogenides have attracted great interest as potential substitutes of nature enzymes in the colorimetric biological sensing due to their unique chemodynamic characteristics.Herein,we report the preparation of ultrathin Fe S nanosheets(NSs)by a simple one-pot hydrothermal method and the prepared Fe S NSs exhibit strong Fenton-reaction activity to catalyze hydrogen peroxide(H_(2)O_(2))for generation of hydroxyl radical(^(·)OH).Based on the chromogenic reaction of resultant^(·)OH with 3,3,5,5-tetramethylbenzidine(TMB),we develop colorimetric biosensors for highly sensitive detection of H_(2)O_(2)and glutathione(GSH).The fabricated biosensors show wide linear ranges for the detection of H_(2)O_(2)(5–150μmol/L)and GSH(5–50μmol/L).Their detection limits for H_(2)O_(2)and GSH reach as low as0.19μmol/L and 0.14μmol/L,respectively.The experimental results of sensing intracellular H_(2)O_(2)and GSH demonstrate that this colorimetric method can realize the accurate detection of H_(2)O_(2)and GSH in normal cells(L02 and 3T3)and cancer cells(MCF-7 and He La).Our results have demonstrated that the synthesized Fe S NSs is a promising material to construct colorimetric biosensors for the sensitive detection of H_(2)O_(2)and GSH,holding great promising for medical diagnosis in cancer therapy.
基金the financial support from the National Natural Science Foundation of China(Nos.21075023,21804021)the Program for Innovative Leading Talents in Fujian Province(No.2016B016)+2 种基金the Joint Funds for the Innovation of Science and Technology,Fujian Province(No.2016Y9056)the Natural Science Foundation of Fujian Province(No.2017J01575)Startup Fund for Scientific Research,Fujian Medical University(No.2017XQ1014)
文摘The development of efficient methods for the detection of hazardous and toxic elements is extremely important for environmental security and public health.In this work,we developed a facile colorimetric assaying system for Ag+detection in aqueous solution.Chitosan-stabilized platinum nanoparticles(ChPtNPs)were synthesized and severed as an artificial oxidase to catalyze the oxidation of the substrate3,30,5,50-tetramethylbenzidine(TMB)and generate color signal.In the presence of Ag+,due to the strong metallophilic interactions between Ag+and Pt^(2+)on the surface of Ch-PtNPs,Ag^(+)can weaken the affinity to the substrates and inactivate the catalytic activity of Ch-PtNPs,leading to decreased absorbance signal to varying degrees depending on Ag+amount.Combing the specific binding between Ch-PtNPs and Ag+with signal amplification procedure based on the Ch-PtNPs-catalyzed TMB oxidation,a sensitive,selective,simple,cost-effective,and rapid detection method for Ag+can be realized.Ag+ions in tap and lake waters have been successfully detected.We ensured that the proposed method can be a potential alternative for Ag+determination in environmental samples.
基金supported by the National Natural Science Foundation of China(No.21876206)the Fundamental Research Funds for the Central Universities(No.18CX02037A)。
文摘Due to the serious harm of diabetes to human health,development of sensitive assays for glucose level is of high significance for early prevention and treatment of diabetes.Currently,most conventional enzyme-based glucose sensors suffer from high cost and low stability due to the inherent defects of natural enzymes.Herein,we develop a pure nanozyme-based glucose detection method using Ag@Au core/shell triangular nanoplates(TNPs),which combines glucose oxidase(GOD)-and horseradish peroxidase(HRP)-like activities of the Au shell and inherent plasmonic properties of Ag TNPs.The sensing mechanism is based on the fact that the Au shell possessed GOD-like activity,enabling the oxidation of glucose to produce H2O2,which can further etch the silver core,leading to the decrease of absorbance at 800 nm and the color change from blue to colorless.Compared with the previous nanozymes-based glucose sensors,our method avoids the use of enzymes and organic chromogenic agent.Moreover,the stability of the Ag@Au core/shell TNPs is much better than that of Ag TNPs due to the protection by the coating of the Au shell.This method was successfully applied to the detection of urine samples from patients with diabetes,indicating its practical applicability for real sample analysis.
基金Project (Nos.2005C22035 and 2005C12015) supported by theDepartment of Science and Technology of Zhejiang Province, China
文摘The objective of this study is to propose a more accurate and faster MTT 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r2=0.975±0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125～32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7～8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24～28 h for ADA. The MCA provides an accurate and rapid method for quantifi-cation of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.
基金the financial support of the Ministry of Science and Technology of the People's Republic of China(No.2006CB 933100).
文摘Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption, but other 19 kinds of natural amino acids could not. Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.
基金financially supported by National Key Research and Development Program of China(2022YFC2601604)Major science and technology project of Yunnan Province(202202AE090085)+9 种基金the National Natural Science Foundation of China(3216059732160236)Science and technology talent and platform plan of YunnanKey Scientific and Technology Project of Yunnan(202203AC100010)Spring City Plan:the High-level Talent Promotion and Training Project of Kunming(2022SCP001)the second phase of“Double-First Class”program construction of Yunnan Universitygrants from State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan,Yunnan University(2021KF005)Key Scientific and Technology Project of Yunnan(202002AE320005)Program for Excellent Young Talents of Yunnan Universitythe Program for Donglu Scholars of Yunnan University。
文摘Norovirus(NoV)is regarded as one of the most common causes of foodborne diarrhea in the world.It is urgent to identify the pathogenic microorganism of the diarrhea in short time.In this work,we developed an electrochemical and colorimetric dual-mode detection for NoV based on the excellent dual catalytic properties of copper peroxide/COF-NH_(2)nanocomposite(CuO_(2)@COF-NH_(2)).For the colorimetric detection,NoV can be directly detected by the naked eye based on CuO_(2)@COF-NH_(2)as a laccase-like nonazyme using“peptide-NoV-antibody”recognition mode.The colorimetric assay displayed a wide and quality linear detection range from 1 copy/mL to 5000 copies/mL of NoV with a low limit of detection(LOD)of 0.125 copy/mL.For the electrochemical detection of NoV,CuO_(2)@COF-NH_(2)showed an oxidation peak of copper ion from Cu^(+)to Cu^(2+)using“peptide-NoV-antibody”recognition mode.The electrochemical assay showed a linear detection range was 1-5000 copies/mL with a LOD of 0.152 copy/mL.It's worthy to note that this assay does not need other electrical signal molecule,which provide the stable and sensitive electrochemial detection for NoV.The electrochemical and colorimetric dual-mode detection was used to detect NoV in foods and faceal samples,which has the potential for improving food safety and diagnosing of NoV-infected diarrhea.
基金supported by the fund of China Tobacco Yunnan Industrial Co. (No. 2015JC05)Foundation of the Department of Science and Technology of Yunnan Province of China (Nos. 2013HB062, 2014HB008)Training Project (No. XT412003) of Yunnan University
文摘A rhodamine-based sensor has been developed for the detection of mercuric ions. The colorimetric and fluorescence responses, allowing naked-eye detections, are based on Hg^2＋-induced opening of the rhodamine spirocycle. Among all the testes ions, only Hg^2＋generated a significant fluorescence enhancement of up to 300-fold, with a bright yellow–green emission. This sensor was a low toxic compound, and was successfully applied in the in vivo imaging of Hg^2＋in Spill 2 cells and C. elegans. This approach provides a sensitive and accurate method for the estimation of Hg^2＋in environmental, tobacco and biological applications.
