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
Development of accurate analytical protocols for cancer biomarkers is used for the initial prescreening of malignant tumors,disease surveillance,and efficacy assessment with significant clinical benefits.In this work,...Development of accurate analytical protocols for cancer biomarkers is used for the initial prescreening of malignant tumors,disease surveillance,and efficacy assessment with significant clinical benefits.In this work,we reported a liposome-mediated signal-off photoelectrochemical(PEC)immunoassay for the sensitive detection of carcinoembryonic antigen(CEA)using ternary transition metal sulfide CuS/ZnCdS as the photoactive material.Good photocurrents were acquired on the basis of specific oxidation reaction of dopamine on the CuS/ZnCdS.The energy band relationship of CuS/ZnCdS was determined,and the wellmatched oxidation potential of dopamine was verified.To achieve accurate recovery of low-abundance CEA,systematic PEC evaluation from human serum samples was performed by combining with classical immunoreaction and liposome-induced dopamine amplification strategy with high stability and selectivity.Under optimum conditions,PEC immunoassay displayed good photocurrent responses toward target CEA with a dynamic linear range of 0.1-50 ng/mL with a detection limit of 31.6 pg/mL.Importantly,this system by combining with a discussion of energy level matching between semiconductor energy bands and small-molecules opens a new horizon for development of high-efficient PEC immunoassays.展开更多
It has been reported that endosperm undergoes programmed cell death (PCD) during maize kernel development.Both bz1 (bronze ) and bz2 are anthocyanin biosynthetic genes,and related to development of aleuronic la...It has been reported that endosperm undergoes programmed cell death (PCD) during maize kernel development.Both bz1 (bronze ) and bz2 are anthocyanin biosynthetic genes,and related to development of aleuronic layer of maize seeds.Tyramide signal amplification fluorescence in situ hybridization (TSA FISH) is a novel and high sensitive FISH technique,which is suitable for routine application in plant cytogenetic research.Using this technique,we physically mapped the bz1 gene onto the short arm of chromosome 9 and the long arm of chromosome 1;the percentage distances from centromere to hybridization site were 40.2,75.4 respectively,and the bz2 onto the long arm of chromosome 1 and the short arm of chromosome 5;the percentage distances from centromere to hybridization site were 21.6,15.3 separately.The TSA FISH techniques of small low copy DNA sequences for plants are discussed.展开更多
Due to their high specificity and affinity towards various targets,along with other unique advantages such as stability and low cost,aptamers are widely applied in analytical techniques.A typical aptamerbased electroc...Due to their high specificity and affinity towards various targets,along with other unique advantages such as stability and low cost,aptamers are widely applied in analytical techniques.A typical aptamerbased electrochemical biosensor is composed of a aptamer as the biological recognition element and transducer converting the biologic interaction into electrical signals for the quantitative measurement of targets.Improvement of the sensitivity of a biosensor is significantly important in order to achieve the detection of biomolecules with low abundance,and different amplification strategies have been explored.The strategies either employ nanomaterials such as gold nanoparticles to con struct electrodes which can transfer the biological reactions more efficiently,or attempt to obtain enhanced signal through multi-labeled carriers or utilize enzyme mimics to catalyze redox cycling.This review discusses recent advances in signal amplification methods and their applications.Critical assessment of each method is also considered.展开更多
Selective and sensitive detection of trace microRNA is important for early diagnosis of diseases due to its expression level related to diseases.Herein,a triple signal amplification strategy is developed for trace mic...Selective and sensitive detection of trace microRNA is important for early diagnosis of diseases due to its expression level related to diseases.Herein,a triple signal amplification strategy is developed for trace microRNA-21 (miRNA-21) detection by combining with target-triggered cyclic strand displacement reaction (TCSDR),hybridization chain reaction (HCR) and enzyme catalytic amplification.Four DNA hairpins(H1,H2,H3,H4) are employed to form an ultralong double-strand DNA (dsDNA) structure,which is initiated by target miRNA-21.As H3 and H4 are labeled with horseradish peroxidase (HRP),numerous HRPs are loaded on the long dsDNA,producing significantly enhanced electrocatalytic signals in the hydrogen peroxide (H_(2)O_(2)) and 3,3,5,5-tetramethylbenzidine (TMB) reaction strategy.Compared with single signal amplification,the triple signal amplification strategy shows higher electrochemical response,wider dynamic range and lower detection limit for miRNA-21 detection with excellent selectivity,reproducibility and stability.Taking advantage of the triple signal amplification strategy,the proposed electrochemical biosensor can detect miRNA-21 in 10 He La cell lysates,suggesting that it is a promising method for fruitful assay in clinical diagnosis.展开更多
Ensuring food safety is paramount worldwide.Developing effective detection methods to ensure food safety can be challenging owing to trace hazards,long detection time,and resource-poor sites,in addition to the matrix ...Ensuring food safety is paramount worldwide.Developing effective detection methods to ensure food safety can be challenging owing to trace hazards,long detection time,and resource-poor sites,in addition to the matrix effects of food.Personal glucose meter(PGM),a classic point-of-care testing device,possesses unique application advantages,demonstrating promise in food safety.Currently,many studies have used PGM-based biosensors and signal amplification technologies to achieve sensitive and specific detection of food hazards.Signal amplification technologies have the potential to greatly improve the analytical performance and integration of PGMs with biosensors,which is crucial for solving the challenges associated with the use of PGMs for food safety analysis.This review introduces the basic detection principle of a PGM-based sensing strategy,which consists of three key factors:target recognition,signal transduction,and signal output.Representative studies of existing PGM-based sensing strategies combined with various signal amplification technologies(nanomaterial-loaded multienzyme labeling,nucleic acid reaction,DNAzyme catalysis,responsive nanomaterial encapsulation,and others)in the field of food safety detection are reviewed.Future perspectives and potential opportunities and challenges associated with PGMs in the field of food safety are discussed.Despite the need for complex sample preparation and the lack of standardization in the field,using PGMs in combination with signal amplification technology shows promise as a rapid and cost-effective method for food safety hazard analysis.展开更多
For circulating tumor cells(CTCs)-based cancer diagnosis and monitoring,effective enrichment and specific analysis of CTCs present significant challenges.The biomembrane interfaces can enhance the highaffinity interac...For circulating tumor cells(CTCs)-based cancer diagnosis and monitoring,effective enrichment and specific analysis of CTCs present significant challenges.The biomembrane interfaces can enhance the highaffinity interactions between various receptors and ligands in life activities by mediating the rearrangement and positioning of membrane-bound components through its fluidity.Inspired by this,we have constructed a multivalent membrane nano-interface using aptamer-linked liposomes for the efficient capture of CTCs.Furthermore,the subsequent introduction of rolling circle amplification(RCA)reaction has increased the number of aptamers and extended them to the surrounding space to improve the affinity of the membrane nano-interface for CTCs.After CTCs are enriched,alkaline phosphatase overexpressed on the surface of tumor cells is used as endogenous enzyme-mediated signal amplification by catalyzing 4-nitrophenyl phosphate(p NPP)with color change,achieving the analysis of CTCs.Finally,the enrichment and visual analysis of human hepatocellular carcinoma(HepG2)with a detection limit of 10 cells/m L can be obtained by integrating the multivalent membrane nano-interface and endogenous enzyme signal amplification.The detection of the target in the serum proved this method has the potential for further clinical application and provides a potential method for studying the correlation between alkaline phosphatase dimer and cancer progression.展开更多
The identification of tumor-related microRNAs(miRNAs)exhibits excellent promise for the early diagnosis of cancer and other bioanalytical applications.Therefore,we developed a sensitive and efficient biosensor using p...The identification of tumor-related microRNAs(miRNAs)exhibits excellent promise for the early diagnosis of cancer and other bioanalytical applications.Therefore,we developed a sensitive and efficient biosensor using polyadenine(polyA)-mediated fluorescent spherical nucleic acid(FSNA)for miRNA analysis based on strand displacement reactions on gold nanoparticle(AuNP)surfaces and electrokinetic signal amplification(ESA)on a microfluidic chip.In this FSNA,polyA-DNA biosensor was anchored on AuNP surfaces via intrinsic affinity between adenine and Au.The upright conformational polyA-DNA recognition block hybridized with 6-carboxyfluorescein-labeled reporter-DNA,resulting in fluorescence quenching of FSNA probes induced by AuNP-based resonance energy transfer.Reporter DNA was replaced in the presence of target miRNA,leading to the recovery of reporter-DNA fluorescence.Subsequently,reporter-DNAs were accumulated and detected in the front of with Nafion membrane in the microchannel by ESA.Our method showed high selectivity and sensitivity with a limit of detection of 1.3 pM.This method could also be used to detect miRNA-21 in human serum and urine samples,with recoveries of 104.0%-113.3% and 104.9%-108.0%,respectively.Furthermore,we constructed a chip with three parallel channels for the simultaneous detection of multiple tumor-related miRNAs(miRNA-21,miRNA-141,and miRNA-375),which increased the detection efficiency.Our universal method can be applied to other DNA/RNA analyses by altering recognition sequences.展开更多
Fungal infections are hazardous to human health that has drawn wide attention.In this work,a specific and sensitive method combing the recognition of aptamer to(1,3)-β-D-glucan and tyramide signal amplification techn...Fungal infections are hazardous to human health that has drawn wide attention.In this work,a specific and sensitive method combing the recognition of aptamer to(1,3)-β-D-glucan and tyramide signal amplification technology was proposed for the in situ fluorescence imaging of fungi.Fungi could be distinctly observed by fluorescence microscope rapidly.This method provides morphology and diagnostic information for identifying fungi.The combination of aptamer and tyramide signal amplification technology is a promising tool for the detection of fungi,bacteria and even eukaryotic cell with the virtue of biomarkers.展开更多
The three-node feedforward motif has been revealed to function as a weak signal amplifier. In this motif, two nodes(input nodes) receive a weak input signal and send it unidirectionally to the third node(output node)....The three-node feedforward motif has been revealed to function as a weak signal amplifier. In this motif, two nodes(input nodes) receive a weak input signal and send it unidirectionally to the third node(output node). Here, we change the motif's unidirectional couplings(feedforward) to bidirectional couplings(feedforward and feedback working together).We find that a small asymmetric coupling, in which the feedforward effect is stronger than the feedback effect, may enable the three-node motif to go through two distinct dynamic transitions, giving rise to a double resonant signal response. We present an analytical description of the double resonance, which agrees with the numerical findings.展开更多
An electrochemical immunosensor for sensitive detection of thyroid stimulating hormone(TSH) has been developed by using an inkjet printed microchip and based on a double signal amplification strategy using magnetic be...An electrochemical immunosensor for sensitive detection of thyroid stimulating hormone(TSH) has been developed by using an inkjet printed microchip and based on a double signal amplification strategy using magnetic beads(MBs), alkaline phosphatase(ALP) and p-aminophenyl phosphate(pAPP) reaction.Differential pulse voltammetry(DPV), cyclic voltammogram(CV) and amperometric i-t curve(i-t) were employed to characterize the immunosensor. High sensitivity and good selectivity were observed. The detection linear range was from 0.01 μIU/mL to 10 μIU/mL, in which the peak currents increased along with the concentration. The detection limit was 0.005 μIU/mL at S/N = 3. The immunosensor was also applied for TSH detection in human serum with recoveries from 98.0% to 101.8% and relative standard deviations from 1.3% to 3.1%, demonstrating potential value in clinical diagnosis.展开更多
BACKGROUND Malignant tumors are one of the leading causes of death worldwide,imposing a substantial economic and social burden.Early detection is the key to improving cure rates and reducing mortality rates,which requ...BACKGROUND Malignant tumors are one of the leading causes of death worldwide,imposing a substantial economic and social burden.Early detection is the key to improving cure rates and reducing mortality rates,which requires the development of sensitive early detection technologies.Signal amplification techniques play a crucial role in aptamer-based early detection of tumors and are increasingly garnering attention from researchers.AIM To investigate the current research status,developmental trajectories,and hotspots in signal amplification for aptamer-based tumor detection through bibliometric analysis.METHODS English publications pertaining to signal amplification in aptamer-based tumor detection were retrieved from the Web of Science Core Collection database.VOSviewer and CiteSpace software were employed to analyze various information within this field,including countries,institutions,authors,co-cited authors,journals,co-cited journals,cited references,and keywords.RESULTS A total of 757 publications were included in this study.China accounted for 85.47%of all publications,with Nanjing University(China)emerging as the institution with the highest publication output.The most influential authors and journals were Hasanzadeh M.from Iran and"Biosensors and Bioelectronics",respectively.Exosomes and carcinoembryonic antigen(CEA)stood out as the most researched tumor-related molecules.Currently,the predominant signal amplification technique,nanomaterial,and signal transduction method were identified as hybridization chain reactions,gold nanoparticles,and electrochemical methods,respectively.Over the past 3 years,exosomes,CEA,electrochemical biosensors,and nanosheets have emerged as research hotspots,exhibiting a robust burst of intensity.CONCLUSION This study is the first bibliometric analysis of literature on signal amplification in aptamer-based tumor detection and elucidates the current status,hotspots,and prospective research directions within this realm.Additionally,it provides an important reference for researchers.展开更多
It has been found that a triple-node feed-forward motif has a function of signal amplification, where two input nodes receive the external weak signal and jointly modulate the response of the third output node [Liang ...It has been found that a triple-node feed-forward motif has a function of signal amplification, where two input nodes receive the external weak signal and jointly modulate the response of the third output node [Liang et al.,Phys. Rev. E 88（2013） 012910]. We here show that the signal amplification can be further enhanced by adding a link between the two input nodes in the feed-forward motif. We further reveal that the coupling strength of the link regulates the enhancement of signal amplification in the modified feed-forward motif. We finally analyze the mechanism of signal amplification of such simple structure.展开更多
Dairy products have become one of the most prevalent daily foods worldwide,but safety concerns are rising.In dairy farming,unscrupulous traders misuse antibiotics to treat some diseases such as mastitis in cows,leadin...Dairy products have become one of the most prevalent daily foods worldwide,but safety concerns are rising.In dairy farming,unscrupulous traders misuse antibiotics to treat some diseases such as mastitis in cows,leading to antibiotic residues in dairy products.Rapid,sensitive,and simple detection methods for antibiotic residues are particularly important for food safety in dairy products.Traditional detection technology can effectively detect antibiotics,but there are defects such as complicated pre-treatment and high cost.Biosensors are widely used in food safety due to fast detection speed,low detection cost,strong anti-interference ability,and suitability for the field application.Nevertheless,these sensors often fail to trigger the signal conversion output due to low target concentration.To cope with this issue,some high-efficiency signal amplification systems can be introduced to improve the detection sensitivity and linear range of biosensors.In this review,we focused on:(i)Sources and toxicity of major antibiotics in animal-derived foods.(ii)Nanomaterial-mediated biosensors for real-time detection of target antibiotics in animal-derived foods.(iii)Signal amplification techniques to increase the sensitivity of biosensors.Finally,future prospects and challenges in this research field are discussed.展开更多
Glial fibrillary acidic protein(GFAP)is one of the discriminative biomarkers for diagnosing traumatic brain injury(TBI),and accurate determination of GFAP is clinically significant.In this study,a novel fluorescence i...Glial fibrillary acidic protein(GFAP)is one of the discriminative biomarkers for diagnosing traumatic brain injury(TBI),and accurate determination of GFAP is clinically significant.In this study,a novel fluorescence immunoassay system was designed.We encapsulated carbon dots with a high fluorescence quantum yield(QY=92.5%)inside silicon nanocapsules to serve as fluorescent markers.These markers were then integrated with the streptavidin(SA)-biotin biomagnification system and immunomagnetic separation technology for the sensitive detection of GFAP.Based on the signal cascade amplification effect of the silicon nanocapsules and SA-biotin,the fluorescence signal of the SA-biotin-modified immunofluorescence nanocapsules increased 3.6-fold compared to the carbon dot-based immunoprobe.The fluorescence immunoassay system was constructed for GFAP using SA-biotin-modified immunocapsules as the sensing probe and immunomagnetic nanoparticles as the immunorecognition probe.The fluorescence immunoassay system can specifically and ultra-sensitively quantify GFAP in blood samples,with a detection range of 10 pg/mL–10 ng/mL and detection limits of 3.2 pg/mL(serum)and 3.6 pg/mL(plasma).Moreover,the fluorescence immunoassay system exhibited prominent recoveries of 99.4%–100.4%(phosphate buffered saline),96%–102.6%(serum),and 93.2%–110.2%(plasma),with favorable specificity and excellent stabilization.The novel fluorescence immunoassay system provides a new approach to the clinical analysis of GFAP and may serve as a potential tool for screening and diagnosing TBI.展开更多
A highly sensitive electrochemical aptasensor was developed for the detection of kanamycin,employing a DNA signal amplification strategy that combines RecJf exonuclease-assisted target recycling with a hybridization c...A highly sensitive electrochemical aptasensor was developed for the detection of kanamycin,employing a DNA signal amplification strategy that combines RecJf exonuclease-assisted target recycling with a hybridization chain reaction(HCR).The sensing platform is constructed by covalently immobilizing double-stranded DNA(dsDNA)comprised of a kanamycin-specific aptamer and its thiol-modified complementary strand(SH-CDNA)onto a gold electrode.In the presence of kanamycin and RecJf exonuclease,the aptamer selectively binds to kanamycin,dissociating from the dsDNA complex.The RecJf exonuclease then cleaves the aptamer,releasing kanamycin and initiating a cycle of repetitive binding and release.The residual SH-CDNA on the electrode triggers an HCR between two types of ferrocene-labeled hairpin DNA,forming an elongated stable dsDNA nanostructure.This results in an amplified electrochemical signal proportional to the logarithm of kanamycin concentration over a range of 0.01–10 nmol/L,with a remarkable detection limit of 1.8 pmol/L.The aptasensor's performance was validated by analyzing spiked kanamycin in pharmaceutical eye drops and milk samples,yielding recovery rates between 95.6%and 104.8%and relative standard deviations from 1.4%to 4.2%.With its exceptional selectivity and sensitivity,this aptasensor offers a compelling alternative to traditional HPLC for rapid on-site detection of kanamycin.Capitalizing on the specificity of aptamers,the sensor design presented herein serves as a valuable blueprint for engineering detectors of other molecules,with significant implications for analytical chemistry and food safety monitoring.展开更多
The simultaneous detection of carcinoembryonic antigen(CEA)and microRNA-21(miR-21)is of significant clinical importance for cancer diagnosis,prognosis evaluation,and therapy monitoring.In this study,we developed a nov...The simultaneous detection of carcinoembryonic antigen(CEA)and microRNA-21(miR-21)is of significant clinical importance for cancer diagnosis,prognosis evaluation,and therapy monitoring.In this study,we developed a novel electrochemical biosensor utilizing a peptide-self-assembly-engineered signal amplification(PSA-e-SA)nanoarchitectonic strategy to achieve ultrasensitive and simultaneous quantification of these two critical biomarkers.By designing amphiphilic peptides(C_(16)-MB-AptamerCEA and C_(16)-Fc-ssDNA2)as multifunctional probes,the system exploits their dual roles in target recognition and signal amplification.These peptides self-assemble into nanostructures under mild conditions,facilitating enhanced loading of electroactive molecules such as methylene blue(MB)and ferrocene(Fc),thereby significantly amplifying the electrochemical signal.The biosensor achieved detection limits of 0.788 pM for CEA and 0.0357 nM for miR-21,demonstrating remarkable sensitivity enhancements of 18-fold and 3.8-fold compared to unamplified approaches.As a proof-of-concept study,further experiments underscored the excellent reproducibility and stability of the strategy while also demonstrating its applicability when tested with simulated serum samples.Thus,this work not only presents a valuable assay tool for early cancer diagnosis and biomarker analysis but also indicates that this signal amplification strategy based on peptide self-assembly engineering can be extended to detect other disease-related biomarkers,propelling the development of clinical applications for multifunctional biosensors.展开更多
Sensitive and accurate detection of biological analytes,such as proteins,genes,small molecules,ions,cells,etc.,has been a significant project in life science.Signal amplification is one of the most effective approache...Sensitive and accurate detection of biological analytes,such as proteins,genes,small molecules,ions,cells,etc.,has been a significant project in life science.Signal amplification is one of the most effective approaches to improve the sensitivity of bioanalysis.Taking advantage of specific base pairing,programmable operation,and predictable assembly,DNA is flexible and suitable to perform the signal amplification procedure.In recent years,signal amplification strategies by means of DNA technology have been widely integrated into the construction of electrochemiluminescence(ECL)biosensors,achieving desirable analytical performance in clinical diagnosis,biomedical research,and drug development.To the best of our knowledge,these DNA signal amplification technologies mainly include classical polymerase chain reaction,and various amplification approaches conducted under mild conditions,such as rolling circle amplification(RCA)or hyperbranched RCA,cleaving enzyme-assisted amplification,DNAzyme-involved amplification,toehold-mediated DNA strand displacement amplification without enzyme participation,and so on.This review overviews the recent advancements of DNA signal amplification strategies for bioanalysis in the ECL realm,sketching the creative trajectory from strategies design to ultrasensitive ECL platform construction and resulting applications.展开更多
Human T-cell lymphophilic virus type 1(HTLV-1),the known retrovirus causing cancer in humans,is closely associated with adult T-cell leukemia/lymphoma and HTLV-1 associated myelopathy/tropical spastic paraparesis.Due ...Human T-cell lymphophilic virus type 1(HTLV-1),the known retrovirus causing cancer in humans,is closely associated with adult T-cell leukemia/lymphoma and HTLV-1 associated myelopathy/tropical spastic paraparesis.Due to its ability to evade the host's defense mechanisms,early tracking of HTLV-1 becomes crucial.In this study,we integrateλ-Exonuclease(λ-Exo)-assisted target recycling with a terminal deoxynucleotidyl transferase(TdT)-mediated template-free DNA extension process to develop an electrochemical analysis platform for the specific and sensitive detection of HTLV-1 DNA.During theλ-Exo-assisted target recycling,HTLV-1 DNA is recognized by hairpin DNA(Hp-DNA),forming double-stranded DNA(dsDNA)through DNA hybridization.The dsDNA,featuring blunt 5'terminal phosphorylation,is cleaved byλ-Exo,generating abundant short output sequence(sDNA).HTLV-1 DNA is released,initiating a cyclic hybridization-cleavage process.Subsequently,thiol-labelled capture DNA(CP-DNA)assembled on gold electrode surface captures a substantial amount of the generated sDNA,forming CP-DNA-sDNA nanostructures.When TdT and dNTPs are present on the electrode surface,the 3'-OH terminal of sDNA extends to generate long single-stranded DNA(ssDNA)structure.Methylene blue(MB)is selected as the electrochemical signal molecule.MB not only binds with ssDNA but also interacts specifically with dsDNA,resulting in a significantly enhanced electrochemical signal on modified electrode surface.The detection limit of HTLV-1 DNA is as low as 19 amol/L(S/N=3)when the two signal amplification strategies are combined.The analysis platform exhibits excellent analytical performance and holds promise as a novel tool for the early tracing and diagnosis of HTLV-1 DNA.展开更多
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financial support from the National Natural Science Foundation of China(Nos.22274022 and 21874022).
文摘Development of accurate analytical protocols for cancer biomarkers is used for the initial prescreening of malignant tumors,disease surveillance,and efficacy assessment with significant clinical benefits.In this work,we reported a liposome-mediated signal-off photoelectrochemical(PEC)immunoassay for the sensitive detection of carcinoembryonic antigen(CEA)using ternary transition metal sulfide CuS/ZnCdS as the photoactive material.Good photocurrents were acquired on the basis of specific oxidation reaction of dopamine on the CuS/ZnCdS.The energy band relationship of CuS/ZnCdS was determined,and the wellmatched oxidation potential of dopamine was verified.To achieve accurate recovery of low-abundance CEA,systematic PEC evaluation from human serum samples was performed by combining with classical immunoreaction and liposome-induced dopamine amplification strategy with high stability and selectivity.Under optimum conditions,PEC immunoassay displayed good photocurrent responses toward target CEA with a dynamic linear range of 0.1-50 ng/mL with a detection limit of 31.6 pg/mL.Importantly,this system by combining with a discussion of energy level matching between semiconductor energy bands and small-molecules opens a new horizon for development of high-efficient PEC immunoassays.
文摘It has been reported that endosperm undergoes programmed cell death (PCD) during maize kernel development.Both bz1 (bronze ) and bz2 are anthocyanin biosynthetic genes,and related to development of aleuronic layer of maize seeds.Tyramide signal amplification fluorescence in situ hybridization (TSA FISH) is a novel and high sensitive FISH technique,which is suitable for routine application in plant cytogenetic research.Using this technique,we physically mapped the bz1 gene onto the short arm of chromosome 9 and the long arm of chromosome 1;the percentage distances from centromere to hybridization site were 40.2,75.4 respectively,and the bz2 onto the long arm of chromosome 1 and the short arm of chromosome 5;the percentage distances from centromere to hybridization site were 21.6,15.3 separately.The TSA FISH techniques of small low copy DNA sequences for plants are discussed.
基金This work was financially supported by the National Key Research and Development Program of China(No.2017YFA0205301)the National Natural Science Foundation of China(Nos.61527806,81902153 and 61871180)+1 种基金the Clinical Advanced Technology of Social Development Projects in Jiangsu Province(No.BE2018695)the Natural Science Foundation of Hunan Province(No.2017JJ2069).
文摘Due to their high specificity and affinity towards various targets,along with other unique advantages such as stability and low cost,aptamers are widely applied in analytical techniques.A typical aptamerbased electrochemical biosensor is composed of a aptamer as the biological recognition element and transducer converting the biologic interaction into electrical signals for the quantitative measurement of targets.Improvement of the sensitivity of a biosensor is significantly important in order to achieve the detection of biomolecules with low abundance,and different amplification strategies have been explored.The strategies either employ nanomaterials such as gold nanoparticles to con struct electrodes which can transfer the biological reactions more efficiently,or attempt to obtain enhanced signal through multi-labeled carriers or utilize enzyme mimics to catalyze redox cycling.This review discusses recent advances in signal amplification methods and their applications.Critical assessment of each method is also considered.
基金supported by the National Key Research and Development Program of China (No. 2017YFA0205302)the Natural Science Foundation of Jiangsu Province-Major Project (No. BK20212012)+2 种基金the National Natural Science Foundation of China (No. 21874071)the “Six Talents Peak” Foundation of Jiangsu Province (No. SWYY-046)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD, No. YX030003)。
文摘Selective and sensitive detection of trace microRNA is important for early diagnosis of diseases due to its expression level related to diseases.Herein,a triple signal amplification strategy is developed for trace microRNA-21 (miRNA-21) detection by combining with target-triggered cyclic strand displacement reaction (TCSDR),hybridization chain reaction (HCR) and enzyme catalytic amplification.Four DNA hairpins(H1,H2,H3,H4) are employed to form an ultralong double-strand DNA (dsDNA) structure,which is initiated by target miRNA-21.As H3 and H4 are labeled with horseradish peroxidase (HRP),numerous HRPs are loaded on the long dsDNA,producing significantly enhanced electrocatalytic signals in the hydrogen peroxide (H_(2)O_(2)) and 3,3,5,5-tetramethylbenzidine (TMB) reaction strategy.Compared with single signal amplification,the triple signal amplification strategy shows higher electrochemical response,wider dynamic range and lower detection limit for miRNA-21 detection with excellent selectivity,reproducibility and stability.Taking advantage of the triple signal amplification strategy,the proposed electrochemical biosensor can detect miRNA-21 in 10 He La cell lysates,suggesting that it is a promising method for fruitful assay in clinical diagnosis.
基金supported by the Natural Science Foundation of Shandong Province(Grant No.:ZR2020QC250)China Agriculture Research System(Grant No.:CARS-38)+1 种基金Modern Agricultural Technology Industry System of Shandong Province(Grant No.:SDAIT10-10)Key Technology Research and Development Program of Shandong(Grant Nos.:2021CXGC010809 and 2021TZXD012).
文摘Ensuring food safety is paramount worldwide.Developing effective detection methods to ensure food safety can be challenging owing to trace hazards,long detection time,and resource-poor sites,in addition to the matrix effects of food.Personal glucose meter(PGM),a classic point-of-care testing device,possesses unique application advantages,demonstrating promise in food safety.Currently,many studies have used PGM-based biosensors and signal amplification technologies to achieve sensitive and specific detection of food hazards.Signal amplification technologies have the potential to greatly improve the analytical performance and integration of PGMs with biosensors,which is crucial for solving the challenges associated with the use of PGMs for food safety analysis.This review introduces the basic detection principle of a PGM-based sensing strategy,which consists of three key factors:target recognition,signal transduction,and signal output.Representative studies of existing PGM-based sensing strategies combined with various signal amplification technologies(nanomaterial-loaded multienzyme labeling,nucleic acid reaction,DNAzyme catalysis,responsive nanomaterial encapsulation,and others)in the field of food safety detection are reviewed.Future perspectives and potential opportunities and challenges associated with PGMs in the field of food safety are discussed.Despite the need for complex sample preparation and the lack of standardization in the field,using PGMs in combination with signal amplification technology shows promise as a rapid and cost-effective method for food safety hazard analysis.
基金supported by the National Natural Science Foundation of China(No.81672570)the State Key Laboratory of Natural and Biomimetic Drugs(No.K202009)。
文摘For circulating tumor cells(CTCs)-based cancer diagnosis and monitoring,effective enrichment and specific analysis of CTCs present significant challenges.The biomembrane interfaces can enhance the highaffinity interactions between various receptors and ligands in life activities by mediating the rearrangement and positioning of membrane-bound components through its fluidity.Inspired by this,we have constructed a multivalent membrane nano-interface using aptamer-linked liposomes for the efficient capture of CTCs.Furthermore,the subsequent introduction of rolling circle amplification(RCA)reaction has increased the number of aptamers and extended them to the surrounding space to improve the affinity of the membrane nano-interface for CTCs.After CTCs are enriched,alkaline phosphatase overexpressed on the surface of tumor cells is used as endogenous enzyme-mediated signal amplification by catalyzing 4-nitrophenyl phosphate(p NPP)with color change,achieving the analysis of CTCs.Finally,the enrichment and visual analysis of human hepatocellular carcinoma(HepG2)with a detection limit of 10 cells/m L can be obtained by integrating the multivalent membrane nano-interface and endogenous enzyme signal amplification.The detection of the target in the serum proved this method has the potential for further clinical application and provides a potential method for studying the correlation between alkaline phosphatase dimer and cancer progression.
基金supported financially by the National Natural Science Foundation of China(Grant No.:81973282)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.:2018A030313843 and 2021A1515011493)+3 种基金National College Students Innovation and Entrepreneurship Training Program(Grant No.:202012121024)Science and Technology Innovation Strategic Special Project of Guangdong Province("Climbing Program"Special ProjectGrantNo.:pdjh2022b0106)Guangdong College Students Innovation and Entrepreneurship Training Program(Grant No.:S202112121154).
文摘The identification of tumor-related microRNAs(miRNAs)exhibits excellent promise for the early diagnosis of cancer and other bioanalytical applications.Therefore,we developed a sensitive and efficient biosensor using polyadenine(polyA)-mediated fluorescent spherical nucleic acid(FSNA)for miRNA analysis based on strand displacement reactions on gold nanoparticle(AuNP)surfaces and electrokinetic signal amplification(ESA)on a microfluidic chip.In this FSNA,polyA-DNA biosensor was anchored on AuNP surfaces via intrinsic affinity between adenine and Au.The upright conformational polyA-DNA recognition block hybridized with 6-carboxyfluorescein-labeled reporter-DNA,resulting in fluorescence quenching of FSNA probes induced by AuNP-based resonance energy transfer.Reporter DNA was replaced in the presence of target miRNA,leading to the recovery of reporter-DNA fluorescence.Subsequently,reporter-DNAs were accumulated and detected in the front of with Nafion membrane in the microchannel by ESA.Our method showed high selectivity and sensitivity with a limit of detection of 1.3 pM.This method could also be used to detect miRNA-21 in human serum and urine samples,with recoveries of 104.0%-113.3% and 104.9%-108.0%,respectively.Furthermore,we constructed a chip with three parallel channels for the simultaneous detection of multiple tumor-related miRNAs(miRNA-21,miRNA-141,and miRNA-375),which increased the detection efficiency.Our universal method can be applied to other DNA/RNA analyses by altering recognition sequences.
基金supported by the National Natural Science Foundation of China(Nos.22174102,21974101,22174101)the Sino-German rapid response funding call for Covid-19 related research(No.C-0008)。
文摘Fungal infections are hazardous to human health that has drawn wide attention.In this work,a specific and sensitive method combing the recognition of aptamer to(1,3)-β-D-glucan and tyramide signal amplification technology was proposed for the in situ fluorescence imaging of fungi.Fungi could be distinctly observed by fluorescence microscope rapidly.This method provides morphology and diagnostic information for identifying fungi.The combination of aptamer and tyramide signal amplification technology is a promising tool for the detection of fungi,bacteria and even eukaryotic cell with the virtue of biomarkers.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12175087 and 12105117)。
文摘The three-node feedforward motif has been revealed to function as a weak signal amplifier. In this motif, two nodes(input nodes) receive a weak input signal and send it unidirectionally to the third node(output node). Here, we change the motif's unidirectional couplings(feedforward) to bidirectional couplings(feedforward and feedback working together).We find that a small asymmetric coupling, in which the feedforward effect is stronger than the feedback effect, may enable the three-node motif to go through two distinct dynamic transitions, giving rise to a double resonant signal response. We present an analytical description of the double resonance, which agrees with the numerical findings.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21775028,21375022)Scienceand Technology Commission of Shanghai Municipality(Nos.16391903900,17JC1401900,17JC1400200)
文摘An electrochemical immunosensor for sensitive detection of thyroid stimulating hormone(TSH) has been developed by using an inkjet printed microchip and based on a double signal amplification strategy using magnetic beads(MBs), alkaline phosphatase(ALP) and p-aminophenyl phosphate(pAPP) reaction.Differential pulse voltammetry(DPV), cyclic voltammogram(CV) and amperometric i-t curve(i-t) were employed to characterize the immunosensor. High sensitivity and good selectivity were observed. The detection linear range was from 0.01 μIU/mL to 10 μIU/mL, in which the peak currents increased along with the concentration. The detection limit was 0.005 μIU/mL at S/N = 3. The immunosensor was also applied for TSH detection in human serum with recoveries from 98.0% to 101.8% and relative standard deviations from 1.3% to 3.1%, demonstrating potential value in clinical diagnosis.
基金National Natural Science Foundation of China,No.82160494 and No.82160444.
文摘BACKGROUND Malignant tumors are one of the leading causes of death worldwide,imposing a substantial economic and social burden.Early detection is the key to improving cure rates and reducing mortality rates,which requires the development of sensitive early detection technologies.Signal amplification techniques play a crucial role in aptamer-based early detection of tumors and are increasingly garnering attention from researchers.AIM To investigate the current research status,developmental trajectories,and hotspots in signal amplification for aptamer-based tumor detection through bibliometric analysis.METHODS English publications pertaining to signal amplification in aptamer-based tumor detection were retrieved from the Web of Science Core Collection database.VOSviewer and CiteSpace software were employed to analyze various information within this field,including countries,institutions,authors,co-cited authors,journals,co-cited journals,cited references,and keywords.RESULTS A total of 757 publications were included in this study.China accounted for 85.47%of all publications,with Nanjing University(China)emerging as the institution with the highest publication output.The most influential authors and journals were Hasanzadeh M.from Iran and"Biosensors and Bioelectronics",respectively.Exosomes and carcinoembryonic antigen(CEA)stood out as the most researched tumor-related molecules.Currently,the predominant signal amplification technique,nanomaterial,and signal transduction method were identified as hybridization chain reactions,gold nanoparticles,and electrochemical methods,respectively.Over the past 3 years,exosomes,CEA,electrochemical biosensors,and nanosheets have emerged as research hotspots,exhibiting a robust burst of intensity.CONCLUSION This study is the first bibliometric analysis of literature on signal amplification in aptamer-based tumor detection and elucidates the current status,hotspots,and prospective research directions within this realm.Additionally,it provides an important reference for researchers.
基金Supported by the Program for Professor of Special Appointment（Eastern Scholar） at Shanghai Institutions of Higher Learning under Grant No.QD2015016 the National Natural Science Foundation of China under Grant Nos.11505114 and 11305078
文摘It has been found that a triple-node feed-forward motif has a function of signal amplification, where two input nodes receive the external weak signal and jointly modulate the response of the third output node [Liang et al.,Phys. Rev. E 88（2013） 012910]. We here show that the signal amplification can be further enhanced by adding a link between the two input nodes in the feed-forward motif. We further reveal that the coupling strength of the link regulates the enhancement of signal amplification in the modified feed-forward motif. We finally analyze the mechanism of signal amplification of such simple structure.
基金We thank the Natural Science Foundation of Hubei Province of China(2023AFB330)the China Postdoctoral Science Foundation(2022M721275)the Hubei Provincial Market Supervision Administration Science and Technology Program Project(Hbscjg-KJ2021002)for financial support.
文摘Dairy products have become one of the most prevalent daily foods worldwide,but safety concerns are rising.In dairy farming,unscrupulous traders misuse antibiotics to treat some diseases such as mastitis in cows,leading to antibiotic residues in dairy products.Rapid,sensitive,and simple detection methods for antibiotic residues are particularly important for food safety in dairy products.Traditional detection technology can effectively detect antibiotics,but there are defects such as complicated pre-treatment and high cost.Biosensors are widely used in food safety due to fast detection speed,low detection cost,strong anti-interference ability,and suitability for the field application.Nevertheless,these sensors often fail to trigger the signal conversion output due to low target concentration.To cope with this issue,some high-efficiency signal amplification systems can be introduced to improve the detection sensitivity and linear range of biosensors.In this review,we focused on:(i)Sources and toxicity of major antibiotics in animal-derived foods.(ii)Nanomaterial-mediated biosensors for real-time detection of target antibiotics in animal-derived foods.(iii)Signal amplification techniques to increase the sensitivity of biosensors.Finally,future prospects and challenges in this research field are discussed.
基金supported by the AMS Funding Project(No.ZZB2023C7010).
文摘Glial fibrillary acidic protein(GFAP)is one of the discriminative biomarkers for diagnosing traumatic brain injury(TBI),and accurate determination of GFAP is clinically significant.In this study,a novel fluorescence immunoassay system was designed.We encapsulated carbon dots with a high fluorescence quantum yield(QY=92.5%)inside silicon nanocapsules to serve as fluorescent markers.These markers were then integrated with the streptavidin(SA)-biotin biomagnification system and immunomagnetic separation technology for the sensitive detection of GFAP.Based on the signal cascade amplification effect of the silicon nanocapsules and SA-biotin,the fluorescence signal of the SA-biotin-modified immunofluorescence nanocapsules increased 3.6-fold compared to the carbon dot-based immunoprobe.The fluorescence immunoassay system was constructed for GFAP using SA-biotin-modified immunocapsules as the sensing probe and immunomagnetic nanoparticles as the immunorecognition probe.The fluorescence immunoassay system can specifically and ultra-sensitively quantify GFAP in blood samples,with a detection range of 10 pg/mL–10 ng/mL and detection limits of 3.2 pg/mL(serum)and 3.6 pg/mL(plasma).Moreover,the fluorescence immunoassay system exhibited prominent recoveries of 99.4%–100.4%(phosphate buffered saline),96%–102.6%(serum),and 93.2%–110.2%(plasma),with favorable specificity and excellent stabilization.The novel fluorescence immunoassay system provides a new approach to the clinical analysis of GFAP and may serve as a potential tool for screening and diagnosing TBI.
基金financially supported by Central Government Guided Local Science and Technology Development Fund Project(guikeZY22096017)Natural Science Foundation of Guangxi Province(2024GXNSFDA010036)National Natural Science Foundation of China(22164014,U23A2089)。
文摘A highly sensitive electrochemical aptasensor was developed for the detection of kanamycin,employing a DNA signal amplification strategy that combines RecJf exonuclease-assisted target recycling with a hybridization chain reaction(HCR).The sensing platform is constructed by covalently immobilizing double-stranded DNA(dsDNA)comprised of a kanamycin-specific aptamer and its thiol-modified complementary strand(SH-CDNA)onto a gold electrode.In the presence of kanamycin and RecJf exonuclease,the aptamer selectively binds to kanamycin,dissociating from the dsDNA complex.The RecJf exonuclease then cleaves the aptamer,releasing kanamycin and initiating a cycle of repetitive binding and release.The residual SH-CDNA on the electrode triggers an HCR between two types of ferrocene-labeled hairpin DNA,forming an elongated stable dsDNA nanostructure.This results in an amplified electrochemical signal proportional to the logarithm of kanamycin concentration over a range of 0.01–10 nmol/L,with a remarkable detection limit of 1.8 pmol/L.The aptasensor's performance was validated by analyzing spiked kanamycin in pharmaceutical eye drops and milk samples,yielding recovery rates between 95.6%and 104.8%and relative standard deviations from 1.4%to 4.2%.With its exceptional selectivity and sensitivity,this aptasensor offers a compelling alternative to traditional HPLC for rapid on-site detection of kanamycin.Capitalizing on the specificity of aptamers,the sensor design presented herein serves as a valuable blueprint for engineering detectors of other molecules,with significant implications for analytical chemistry and food safety monitoring.
基金the National Natural Science Foundation of China(Nos.22004051 and 22072060)the Natural Science Foundation of Jiangsu Province(No.BK20180858)+4 种基金the China Postdoctoral Science Foundation(No.2019M661733)the Scientific Research Starting Foundation for Senior Talent at Jiangsu University(No.18JDG025)Science Foundation of Wuxi Health Committee(No.BJ202220)Top Talent Support Program for young and middle-aged people of WuxiHealth Committee(No.BJ2023105)Opening of Jiangsu Provincial Key Laboratory of Laboratory Medicine(No.JSKLM-T-2024-1).
文摘The simultaneous detection of carcinoembryonic antigen(CEA)and microRNA-21(miR-21)is of significant clinical importance for cancer diagnosis,prognosis evaluation,and therapy monitoring.In this study,we developed a novel electrochemical biosensor utilizing a peptide-self-assembly-engineered signal amplification(PSA-e-SA)nanoarchitectonic strategy to achieve ultrasensitive and simultaneous quantification of these two critical biomarkers.By designing amphiphilic peptides(C_(16)-MB-AptamerCEA and C_(16)-Fc-ssDNA2)as multifunctional probes,the system exploits their dual roles in target recognition and signal amplification.These peptides self-assemble into nanostructures under mild conditions,facilitating enhanced loading of electroactive molecules such as methylene blue(MB)and ferrocene(Fc),thereby significantly amplifying the electrochemical signal.The biosensor achieved detection limits of 0.788 pM for CEA and 0.0357 nM for miR-21,demonstrating remarkable sensitivity enhancements of 18-fold and 3.8-fold compared to unamplified approaches.As a proof-of-concept study,further experiments underscored the excellent reproducibility and stability of the strategy while also demonstrating its applicability when tested with simulated serum samples.Thus,this work not only presents a valuable assay tool for early cancer diagnosis and biomarker analysis but also indicates that this signal amplification strategy based on peptide self-assembly engineering can be extended to detect other disease-related biomarkers,propelling the development of clinical applications for multifunctional biosensors.
基金financially supported by the National Natural Science Foundation of China(21834004 and 21904063)the Natural Science Foundation of Jiangsu Province(BK20190279)the Fundamental Research Funds for the Central Universities(021314380151)
文摘Sensitive and accurate detection of biological analytes,such as proteins,genes,small molecules,ions,cells,etc.,has been a significant project in life science.Signal amplification is one of the most effective approaches to improve the sensitivity of bioanalysis.Taking advantage of specific base pairing,programmable operation,and predictable assembly,DNA is flexible and suitable to perform the signal amplification procedure.In recent years,signal amplification strategies by means of DNA technology have been widely integrated into the construction of electrochemiluminescence(ECL)biosensors,achieving desirable analytical performance in clinical diagnosis,biomedical research,and drug development.To the best of our knowledge,these DNA signal amplification technologies mainly include classical polymerase chain reaction,and various amplification approaches conducted under mild conditions,such as rolling circle amplification(RCA)or hyperbranched RCA,cleaving enzyme-assisted amplification,DNAzyme-involved amplification,toehold-mediated DNA strand displacement amplification without enzyme participation,and so on.This review overviews the recent advancements of DNA signal amplification strategies for bioanalysis in the ECL realm,sketching the creative trajectory from strategies design to ultrasensitive ECL platform construction and resulting applications.
基金financially supported by Central Leading Local Science and Technology Development Fund Project(guikeZY22096017)Natural Science Foundation of Guangxi Province(2024GXNSFDA010036)National Natural Science Foundation of China(22164014,U23A2089).
文摘Human T-cell lymphophilic virus type 1(HTLV-1),the known retrovirus causing cancer in humans,is closely associated with adult T-cell leukemia/lymphoma and HTLV-1 associated myelopathy/tropical spastic paraparesis.Due to its ability to evade the host's defense mechanisms,early tracking of HTLV-1 becomes crucial.In this study,we integrateλ-Exonuclease(λ-Exo)-assisted target recycling with a terminal deoxynucleotidyl transferase(TdT)-mediated template-free DNA extension process to develop an electrochemical analysis platform for the specific and sensitive detection of HTLV-1 DNA.During theλ-Exo-assisted target recycling,HTLV-1 DNA is recognized by hairpin DNA(Hp-DNA),forming double-stranded DNA(dsDNA)through DNA hybridization.The dsDNA,featuring blunt 5'terminal phosphorylation,is cleaved byλ-Exo,generating abundant short output sequence(sDNA).HTLV-1 DNA is released,initiating a cyclic hybridization-cleavage process.Subsequently,thiol-labelled capture DNA(CP-DNA)assembled on gold electrode surface captures a substantial amount of the generated sDNA,forming CP-DNA-sDNA nanostructures.When TdT and dNTPs are present on the electrode surface,the 3'-OH terminal of sDNA extends to generate long single-stranded DNA(ssDNA)structure.Methylene blue(MB)is selected as the electrochemical signal molecule.MB not only binds with ssDNA but also interacts specifically with dsDNA,resulting in a significantly enhanced electrochemical signal on modified electrode surface.The detection limit of HTLV-1 DNA is as low as 19 amol/L(S/N=3)when the two signal amplification strategies are combined.The analysis platform exhibits excellent analytical performance and holds promise as a novel tool for the early tracing and diagnosis of HTLV-1 DNA.
