A nucleic acid sequence-based amplification（NASBA）assay was established for the detection of Macrobrachium rosenbergii Nodavirus（MrNV）.The specific primers were designed according to the high conserved region of R...A nucleic acid sequence-based amplification（NASBA）assay was established for the detection of Macrobrachium rosenbergii Nodavirus（MrNV）.The specific primers were designed according to the high conserved region of RNA2 sequence of MrNV.The 224 bp specific amplification product was obtained in positive sample determined with 3%agarose gel electrophoresis,while no product was generated from shrimp infected with other viruses including DNA viruses（IHHNV,WSSV）and RNA viruses（TSV,IMNV,YHV）.The detecting limit of the assay was 8pg nucleic acid,which is more sensitive than that of PCR method.展开更多
Nucleic acid(DNA and RNA)detection and quantification methods play vital roles in molecular biology.With the development of molecular biology,isothermal amplification of DNA/RNA,as a new molecular biology technology,c...Nucleic acid(DNA and RNA)detection and quantification methods play vital roles in molecular biology.With the development of molecular biology,isothermal amplification of DNA/RNA,as a new molecular biology technology,can be amplified under isothermal condition,it has the advantages of high sensitivity,high specificity,and high efficiency,and has been applied in various fields of biotechnology,including disease diagnosis,pathogen detection,food hygiene and safety detection and so on.This paper introduces the progress of isothermal amplification technology,including rolling circle amplification(RCA),nucleic acid sequence-dependent amplification(NASBA),strand displacement amplification(SDA),loop-mediated isothermal amplification(LAMP),helicase-dependent amplification(HDA),recombinase polymerase amplification(RPA),cross-priming amplification(CPA),and its principle,advantages and disadvantages,and application development are briefly summarized.展开更多
Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method, which amplifies DNA with high specificity, sensitivity, rapidity and efficiency under isothermal conditions using a set of fo...Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method, which amplifies DNA with high specificity, sensitivity, rapidity and efficiency under isothermal conditions using a set of four specially designed primers and a Bst DNA polymerase with strand displacement activity. The basic principle, characteristics, development of LAMP and its applications are summarized in this article.展开更多
Exosomal micro RNA(mi RNA) is an ideal candidate of noninvasive biomarker for the early diagnosis of cancer. Sensitive and accurate sensing of abnormal exosomal mi RNA plays essential role for clinical promotion due t...Exosomal micro RNA(mi RNA) is an ideal candidate of noninvasive biomarker for the early diagnosis of cancer. Sensitive and accurate sensing of abnormal exosomal mi RNA plays essential role for clinical promotion due to its close correlation with tumor proliferation and progression. Herein, a microfluidic surface-enhanced Raman scattering(SERS) sensor was proposed for an on-line detection of exosomal mi RNA based on rolling circle amplification(RCA) and tyramine signal amplification(TSA) strategy. The microfluidic chip consists of a magnetic enrichment chamber, a serpentine fluidic mixer and a plasmonic SERS substrate functionalized with capture probes. The released mi RNA activates the capture probe, triggers RCA reaction, and generates a large number of single-stranded DNA products to drive the catalysis of nanotags deposition via TSA, producing numerous “hot spots” to enhance the SERS signals. In merit of the microfluidics chip and nucleic acid-tyramine cascade amplification, the developed SERS sensor significantly improves the sensitivity for the exosomal mi RNA assay, resulting in a limit of detection(LOD) as low as 1 pmol/L and can be successfully applied in the analysis of exosomes secreted from breast tumor cells, which demonstrates the potential utility in practical applications.展开更多
The rapid and accurate detection of peanuts and soybeans allergen is important to the food safety. In this study, Cu-TCPP nanosheet, a kind of ultra-thin metal-organic framework(MOF)was synthesized and applied in loop...The rapid and accurate detection of peanuts and soybeans allergen is important to the food safety. In this study, Cu-TCPP nanosheet, a kind of ultra-thin metal-organic framework(MOF)was synthesized and applied in loop-mediated isothermal amplification(named Cu-TCPP@LAMP), which can inhibit the non-specific amplification by absorbing and precise temperature releasing of single primer. As thus, Cu-TCPP@LAMP can achieve high sensitivity and specific amplification of the target gene. As a result, peanut and soybean allergens genes contained in food were successfully detected with a favorable detection sensitivity(5 ng/μL for peanuts and 10 ng/μL for soybeans)and reliable repeatability(The coefficient of variation was 3.38% for peanuts and 3.33% for soybeans). Moreover, the established method was utilized for detection of several commercial products, and had a high consistency with the standard method. Apart from food allergens, this novel assay can be widely used in other areas, such as pathogen detection, tumor nucleic acid detection and so on.展开更多
BACKGROUND Laparoscopic and endoscopic cooperative surgery is a safe,organ-sparing surgery that achieves full-thickness resection with adequate margins.Recent studies have demonstrated the safety and efficacy of these...BACKGROUND Laparoscopic and endoscopic cooperative surgery is a safe,organ-sparing surgery that achieves full-thickness resection with adequate margins.Recent studies have demonstrated the safety and efficacy of these procedures.However,these techniques are limited by the exposure of the tumor and mucosa to the peritoneal cavity,which could lead to viable cancer cell seeding and the spillage of gastric juice or enteric liquids into the peritoneal cavity.Non-exposed endoscopic wallinversion surgery(NEWS)is highly accurate in determining the resection margins to prevent intraperitoneal contamination because the tumor is inverted into the visceral lumen instead of the peritoneal cavity.Accurate intraoperative assessment of the nodal status could allow stratification of the extent of resection.One-step nucleic acid amplification(OSNA)can provide a rapid method of evaluating nodal tissue,whilst nearinfrared laparoscopy together with indocyanine green can identify relevant nodal tissue intraoperatively.AIM To determine the safety and feasibility of NEWS in early gastric and colon cancers and of adding rapid intraoperative lymph node(LN)assessment with OSNA.METHODS The patient-based experiential portion of our investigations was conducted at the General and Oncological Surgery Unit of the St.Giuseppe Moscati Hospital(Avellino,Italy).Patients with early-stage gastric or colon cancer(diagnosed via endoscopy,endoscopic ultrasound,and computed tomography)were included.All lesions were treated by NEWS procedure with intraoperative OSNA assay between January 2022 and October 2022.LNs were examined intraoperatively with OSNA and postoperatively with conventional histology.We analyzed patient demographics,lesion features,histopathological diagnoses,R0 resection(negative margins)status,adverse events,and follow-up results.Data were collected prospectively and analyzed retrospectively.RESULTS A total of 10 patients(5 males and 5 females)with an average age of 70.4±4.5 years(range:62-78 years)were enrolled in this study.Five patients were diagnosed with gastric cancer.The remaining 5 patients were diagnosed with early-stage colon cancer.The mean tumor diameter was 23.8±11.6 mm(range:15-36 mm).The NEWS procedure was successful in all cases.The mean procedure time was 111.5±10.7 min(range:80-145 min).The OSNA assay revealed no LN metastases in any patients.Histologically complete resection(R0)was achieved in 9 patients(90.0%).There was no recurrence during the follow-up period.CONCLUSION NEWS combined with sentinel LN biopsy and OSNA assay is an effective and safe technique for the removal of selected early gastric and colon cancers in which it is not possible to adopt conventional endoscopic resection techniques.This procedure allows clinicians to acquire additional information on the LN status intraoperatively.展开更多
Current histopathological staging procedures in colorectal cancer(CRC)depend on midline division of the lymph nodes(LNs)with one section of hematoxylin and eosin staining.Cancer cells outside this transection line may...Current histopathological staging procedures in colorectal cancer(CRC)depend on midline division of the lymph nodes(LNs)with one section of hematoxylin and eosin staining.Cancer cells outside this transection line may be missed,which could lead to understaging of Union for International Cancer Control Stage II high-risk patients.The one-step nucleic acid amplification(OSNA)assay has emerged as a rapid molecular diagnostic tool for LN metastases detection.It is a molecular technique that can analyze the entire LN tissue using a reversetranscriptase loop-mediated isothermal amplification reaction to detect tumorspecific cytokeratin 19 mRNA.Our findings suggest that the OSNA assay has a high diagnostic accuracy in detecting metastatic LNs in CRC and a high negative predictive value.OSNA is a standardized,observer-independent technique,which may lead to more accurate staging.It has been suggested that in stage II CRC,the upstaging can reach 25%and these patients can access postoperative adjuvant chemotherapy.Moreover,intraoperative OSNA sentinel node evaluation may allow early CRC to be treated with organ-preserving surgery,while in more advanced-stage disease,a tailored lymphadenectomy can be performed considering the presence of aberrant lymphatic drainage and skip metastases.展开更多
Ultrasensitive detection of nucleic acids is of great significance for precision medicine.Digital polymerase chain reaction(dPCR)is the most sensitive method but requires sophisticated and expensive instruments and a ...Ultrasensitive detection of nucleic acids is of great significance for precision medicine.Digital polymerase chain reaction(dPCR)is the most sensitive method but requires sophisticated and expensive instruments and a long reaction time.Digital PCR-free technologies,which mean the digital assay not relying on thermal cycling to amplify the signal for quantitative detection of nucleic acids at the singlemolecule level,include the digital isothermal amplification techniques(d IATs)and the digital clustered regularly interspaced short palindromic repeats(CRISPR)technologies.They combine the advantages of d PCR and IATs,which could be fast and simple,enabling absolute quantification of nucleic acids at a single-molecule level with minimum instrument,representing the next-generation molecular diagnostic technology.Herein,we systematically summarized the strategies and applications of various dIATs,including the digital loop-mediated isothermal amplification(dLAMP),the digital recombinase polymerase amplification(dRPA),the digital rolling circle amplification(dRCA),the digital nucleic acid sequencebased amplification(d NASBA)and the digital multiple displacement amplification(d MDA),and evaluated the pros and cons of each method.The emerging digital CRISPR technologies,including the detection mechanism of CRISPR and the various strategies for signal amplification,are also introduced comprehensively in this review.The current challenges as well as the future perspectives of the digital PCR-free technology were discussed.展开更多
Hepatitis C virus(HCV)infection represents a significant health problem and represents a heavy load on some countries like Egypt in which about 20%of the total population are infected.Initial infection is usually asym...Hepatitis C virus(HCV)infection represents a significant health problem and represents a heavy load on some countries like Egypt in which about 20%of the total population are infected.Initial infection is usually asymptomatic and result in chronic hepatitis that give rise to complications including cirrhosis and hepatocellular carcinoma.The management of HCV infection should not only be focus on therapy,but also to screen carrier individuals in order to prevent transmission.In the present,molecular detection and quantification of HCV genome by real time polymerase chain reaction(PCR)represent the gold standard in HCV diagnosis and plays a crucial role in the management of therapeutic regimens.However,real time PCR is a complicated approach and of limited distribution.On the other hand,isothermal DNA amplification techniques have been developed and offer molecular diagnosis of infectious dieses at point-of-care.In this review we discuss recombinase polymerase amplification technique and illustrate its diagnostic value over both PCR and other isothermal amplification techniques.展开更多
Enterocytozoon hepatopenaei(EHP)infection has seriously affected prawn culture globally.The symptoms of the infection are not apparent,and traditional detection methods are time consuming and low in accuracy.We develo...Enterocytozoon hepatopenaei(EHP)infection has seriously affected prawn culture globally.The symptoms of the infection are not apparent,and traditional detection methods are time consuming and low in accuracy.We developed a new onsite rapid testing device(size 18.8×16.7×6.6 cm^(3))for EHP based on magnesium pyrophosphate precipitation and facilitated by loop mediated isothermal amplification(LAMP).The design and fabrication of the device enables efficient light absorbance.The device has a highly sensitive detector,high-precision thermal controller,and humanized touch screen.The temperature control precision of the device is 0.2-0.3℃ at 60℃,63℃,and 65℃.The coefficients of variation values(CVV)of the luminous power in one channel at light on and off were found to be 0.0097 and 0.0014,respectively,within 1 h.The CVV of the background,luminous power,and values of eight PCR tubes filled with pure water were all less than 5%.In the EHP experiment,eight samples(including seven positive and one negative)confirmed the effectiveness of the device,and four positive and four negative samples verified whether cross-contamination exists.Among them,the rise time of the curve was about 15 min.These results assert that the developed device exhibits enhanced stability and uniformity and has excellent performance with high sensitivity,good specificity,and low testing time.Moreover,the optimal and minimum absorbance range was 555-655 nm for monitoring the production of LAMP.展开更多
Liquid biopsy is a highly promising method for non-invasive detection of tumor-associated nucleic acid fragments in body fluids but is challenged by the low abundance of nucleic acids of clinical interest and their se...Liquid biopsy is a highly promising method for non-invasive detection of tumor-associated nucleic acid fragments in body fluids but is challenged by the low abundance of nucleic acids of clinical interest and their sequence homology with the vast background of nucleic acids from healthy cells.Recently,programmable endonucleases such as clustered regularly interspaced short palindromic repeats(CRISPR)associated protein(Cas)and prokaryotic Argonautes have been successfully used to remove background nucleic acids and enrich mutant allele fractions,enabling their detection with deep next generation sequencing(NGS).However,the enrichment level achievable with these assays is limited by futile binding events and off-target cleavage.To overcome these shortcomings,we conceived a new assay(Programmable Enzyme-Assisted Selective Exponential Amplification,PASEA)that combines the cleavage of wild type alleles with concurrent polymerase amplification.While PASEA increases the numbers of both wild type and mutant alleles,the numbers of mutant alleles increase at much greater rates,allowing PASEA to achieve an unprecedented level of selective enrichment of targeted alleles.By combining CRISPR-Cas9 based cleavage with recombinase polymerase amplification,we converted samples with0.01%somatic mutant allele fractions(MAFs)to products with 70%MAFs in a single step within 20 min,enabling inexpensive,rapid genotyping with such as Sanger sequencers.Furthermore,PASEA's extraordinary efficiency facilitates sensitive real-time detection of somatic mutant alleles at the point of care with custom designed Exo-RPA probes.Real-time PASEA'performance was proved equivalent to clinical amplification refractory mutation system(ARMS)-PCR and NGS when testing over hundred cancer patients'samples.This strategy has the potential to reduce the cost and time of cancer screening and genotyping,and to enable targeted therapies in resource-limited settings.展开更多
Nucleic acid amplification tests(NAAT)have long been used in laboratory facilities and recently revolutionized the field of molecular diagnostics in point-of-care testing.Digital microfluidics(DMF)has emerged as a pro...Nucleic acid amplification tests(NAAT)have long been used in laboratory facilities and recently revolutionized the field of molecular diagnostics in point-of-care testing.Digital microfluidics(DMF)has emerged as a promising tool to complete the entire NAAT workflow in a miniaturized format with minimum human intervention.Based on electric fields to manipulate independent reaction droplets,the compact DMF system could perform multiple processes simultaneously and automatically in a programmable fashion.This combination is beginning to establish powerful sample-to-answer platforms in remote or resource-limited settings.Herein,we provide a comprehensive overview of the state-of-the-art DMF technology for point-of-care NAAT.This review focused on key principles of DMF platforms and the latest trends in system integration for automated processes of nucleic acid extraction,amplification,and detection.Also,this article discusses current challenges,including control systems,scalability and throughput,as well as future prospects of DMF-based NAAT strategy for the next generation of point-of-care diagnostics.展开更多
Signal amplification is an important issue in DNA nanotechnology and molecular diagnostics.In this work,we report a strategy for the catalytic self-assembly of spherical nucleic acids(SNAs)programmed by two-layer casc...Signal amplification is an important issue in DNA nanotechnology and molecular diagnostics.In this work,we report a strategy for the catalytic self-assembly of spherical nucleic acids(SNAs)programmed by two-layer cascaded DNA circuits through integrating an entropy-driven catalytic network,a catalytic hairpin assembly circuit,and a facile SNA assembly-based reporter system.This integrated system could implement^100,000-fold signal amplification in the presence of 1 pM of input target.Possessing powerful amplification ability of nucleic acid signal,our strategy should be of great potential in fabricating more robust dynamic networks to be applied for signal transduction,DNA computing,and nucleic acid-based diagnostics.展开更多
Background Resource-limited regions face a greater burden of infectious diseases due to limited access to molecular tests,complicating timely diagnosis and management.Current molecular point-of-care tests(POCTs)either...Background Resource-limited regions face a greater burden of infectious diseases due to limited access to molecular tests,complicating timely diagnosis and management.Current molecular point-of-care tests(POCTs)either come with high costs or lack adequate sensitivity and specificity.To facilitate better prevention and control of infectious diseases in underserved areas,we seek to address the need for molecular POCTs that better align with the World Health Organization(WHO)’s ASSURED criteria—Affordable,Sensitive,Specific,User-friendly,Rapid and robust,Equipment-free,and Deliverable to end users.Methods A novel molecular POCT,Pasteur Pipette-assisted isothermal probe amplification(pp-IPA),was developed for malaria detection.Without any microfluidics,this method capturesPlasmodium 18S rRNA in a modified Pasteur pipette using tailed genus-specific probes.After washing,the bound tailed probes are ligated to form a template for subsequent novel isothermal probe amplification using a pair of generic primers,bypassing nucleic acid extraction and reverse transcription.The method was assessed using culturedPlasmodium and compared with real-time quantitative reverse transcription PCR(RT-qPCR)or reverse transcription loop-mediated isothermal amplification(RT-LAMP)in clinical blood samples.Results The entire assay is completed in 60-80 min with minimal hands-on time,using only a Pasteur pipette and a water bath.The pp-IPA’s analytical sensitivity is 1.28×10-4 parasites/μl,with 100%specificity against various blood-borne pathogens causing malaria-like symptoms.Additionally,pp-IPA needs only liquid-transfer skill for operation and the cost is around USD 0.25 per test,making it at least 300 times lower than mainstream POCT platforms.Conclusions Designed to improve the accessibility of molecular detection in resource-limited settings,pp-IPA’s simplicity,affordability,high sensitivity/specificity,and minimal equipment requirements make it a promising point-of-care pathogen identification tool in resource-constrained regions.展开更多
Background:Tuberculosis(TB)remains a major threat to human health,and TB diagnostic methods remain unsatisfactory.Nucleic acid amplification tests(NAATs)show higher sensitivity compared with culture for the diagnosis ...Background:Tuberculosis(TB)remains a major threat to human health,and TB diagnostic methods remain unsatisfactory.Nucleic acid amplification tests(NAATs)show higher sensitivity compared with culture for the diagnosis of pulmonary TB(PTB).However,NAATs are expensive and cannot be easily implemented outside major medical centers.To improve the sensitivity of NAATs for PTB diagnosis,we investigated the predictive factors that might optimize NAAT utilization.Methods:A total of 1263 patients with suspected PTB were enrolled for evaluation.The sensitivity,specificity,and accuracy of methods including smear-microbiology,culture of Mtb and NAAT for Mycobacterium tuberculosis(Mtb)detection in sputum and bronchoalveolar lavage fluid samples were compared.Odds ratios and 95%confidence intervals were used to assess variables that might be associated with positive NAAT results for sputum and bronchoalveolar lavage fluid from patients with suspected PTB.Results:NAAT showed higher sensitivity for Mtb detection(61.1%)when compared with smear(9.0%)and Mtb culture(47.8%).We found that an elevated erythrocyte sedimentation rate,the presence of cavities,and positive interferon-𝛾release assay(IGRA)results were indicative of positive Mtb detection by NAAT.Moreover,individuals who had all three of these characteristics showed an 86%diagnostic positivity for PTB from Mtb detection by NAAT.Conclusions:Our study suggests that an elevated erythrocyte sedimentation rate,a positive IGRA result,and the presence of pulmonary cavities are helpful factors for predicting positive Mtb detection by NAAT.Patients with the three positive clinical markers should undergo NAAT for Mtb detection because they are the most likely individuals to be bacteriologically confirmed as having TB.展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201103034)Huzhou Science and Technology Project(2012GN08,2011ZD2005)Science and Technology Innovation Team Project of Freshwater Aquaculture of Zhejiang Province(2012R10026-11)
文摘A nucleic acid sequence-based amplification（NASBA）assay was established for the detection of Macrobrachium rosenbergii Nodavirus（MrNV）.The specific primers were designed according to the high conserved region of RNA2 sequence of MrNV.The 224 bp specific amplification product was obtained in positive sample determined with 3%agarose gel electrophoresis,while no product was generated from shrimp infected with other viruses including DNA viruses（IHHNV,WSSV）and RNA viruses（TSV,IMNV,YHV）.The detecting limit of the assay was 8pg nucleic acid,which is more sensitive than that of PCR method.
基金supported by grants from Jiangsu Higher Education Institution Innovative Research Team for Science and Technology(2021),the Key Technology Program of Suzhou People’s Livelihood Technology Projects(Grant Nos.SKY2021029,SZS2020311)the Open Project of Jiangsu Biobank of Clinical Resources(TC2021B009)the Qing-Lan Project of Jiangsu Province in China(2021,2022).
文摘Nucleic acid(DNA and RNA)detection and quantification methods play vital roles in molecular biology.With the development of molecular biology,isothermal amplification of DNA/RNA,as a new molecular biology technology,can be amplified under isothermal condition,it has the advantages of high sensitivity,high specificity,and high efficiency,and has been applied in various fields of biotechnology,including disease diagnosis,pathogen detection,food hygiene and safety detection and so on.This paper introduces the progress of isothermal amplification technology,including rolling circle amplification(RCA),nucleic acid sequence-dependent amplification(NASBA),strand displacement amplification(SDA),loop-mediated isothermal amplification(LAMP),helicase-dependent amplification(HDA),recombinase polymerase amplification(RPA),cross-priming amplification(CPA),and its principle,advantages and disadvantages,and application development are briefly summarized.
基金General Administrationof Quality Supervision, Inspection and Quarantine of China(HK001-2007).
文摘Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method, which amplifies DNA with high specificity, sensitivity, rapidity and efficiency under isothermal conditions using a set of four specially designed primers and a Bst DNA polymerase with strand displacement activity. The basic principle, characteristics, development of LAMP and its applications are summarized in this article.
基金supported by the National Natural Science Foundation of China (Nos. 31671013, 22004096, 21874105and 21705124)the China Postdoctoral Science Foundation (Nos.2019M663658 and 2020T130096ZX)+2 种基金the Natural Science Basic Research Program of Shaanxi (Nos. 2020JQ-020, 2020JQ-021 and2018JC-001)the Fundamental Research Funds for the Central Universities (No. xzy012020034)“Young Talent Support Plan” of Xi’an Jiaotong University。
文摘Exosomal micro RNA(mi RNA) is an ideal candidate of noninvasive biomarker for the early diagnosis of cancer. Sensitive and accurate sensing of abnormal exosomal mi RNA plays essential role for clinical promotion due to its close correlation with tumor proliferation and progression. Herein, a microfluidic surface-enhanced Raman scattering(SERS) sensor was proposed for an on-line detection of exosomal mi RNA based on rolling circle amplification(RCA) and tyramine signal amplification(TSA) strategy. The microfluidic chip consists of a magnetic enrichment chamber, a serpentine fluidic mixer and a plasmonic SERS substrate functionalized with capture probes. The released mi RNA activates the capture probe, triggers RCA reaction, and generates a large number of single-stranded DNA products to drive the catalysis of nanotags deposition via TSA, producing numerous “hot spots” to enhance the SERS signals. In merit of the microfluidics chip and nucleic acid-tyramine cascade amplification, the developed SERS sensor significantly improves the sensitivity for the exosomal mi RNA assay, resulting in a limit of detection(LOD) as low as 1 pmol/L and can be successfully applied in the analysis of exosomes secreted from breast tumor cells, which demonstrates the potential utility in practical applications.
基金the Science and Technology Joint Project of the Yangtze River Delta (19395810100)Shanghai Agriculture Project (19391901500)+2 种基金the National Key Research and Development Program of China (2016YFD0501101)the Shanghai Science and Technology Innovation Foundation (19441903900 and 19XD1433000)Project of National Natural Science Foundation of China (82003705)。
文摘The rapid and accurate detection of peanuts and soybeans allergen is important to the food safety. In this study, Cu-TCPP nanosheet, a kind of ultra-thin metal-organic framework(MOF)was synthesized and applied in loop-mediated isothermal amplification(named Cu-TCPP@LAMP), which can inhibit the non-specific amplification by absorbing and precise temperature releasing of single primer. As thus, Cu-TCPP@LAMP can achieve high sensitivity and specific amplification of the target gene. As a result, peanut and soybean allergens genes contained in food were successfully detected with a favorable detection sensitivity(5 ng/μL for peanuts and 10 ng/μL for soybeans)and reliable repeatability(The coefficient of variation was 3.38% for peanuts and 3.33% for soybeans). Moreover, the established method was utilized for detection of several commercial products, and had a high consistency with the standard method. Apart from food allergens, this novel assay can be widely used in other areas, such as pathogen detection, tumor nucleic acid detection and so on.
文摘BACKGROUND Laparoscopic and endoscopic cooperative surgery is a safe,organ-sparing surgery that achieves full-thickness resection with adequate margins.Recent studies have demonstrated the safety and efficacy of these procedures.However,these techniques are limited by the exposure of the tumor and mucosa to the peritoneal cavity,which could lead to viable cancer cell seeding and the spillage of gastric juice or enteric liquids into the peritoneal cavity.Non-exposed endoscopic wallinversion surgery(NEWS)is highly accurate in determining the resection margins to prevent intraperitoneal contamination because the tumor is inverted into the visceral lumen instead of the peritoneal cavity.Accurate intraoperative assessment of the nodal status could allow stratification of the extent of resection.One-step nucleic acid amplification(OSNA)can provide a rapid method of evaluating nodal tissue,whilst nearinfrared laparoscopy together with indocyanine green can identify relevant nodal tissue intraoperatively.AIM To determine the safety and feasibility of NEWS in early gastric and colon cancers and of adding rapid intraoperative lymph node(LN)assessment with OSNA.METHODS The patient-based experiential portion of our investigations was conducted at the General and Oncological Surgery Unit of the St.Giuseppe Moscati Hospital(Avellino,Italy).Patients with early-stage gastric or colon cancer(diagnosed via endoscopy,endoscopic ultrasound,and computed tomography)were included.All lesions were treated by NEWS procedure with intraoperative OSNA assay between January 2022 and October 2022.LNs were examined intraoperatively with OSNA and postoperatively with conventional histology.We analyzed patient demographics,lesion features,histopathological diagnoses,R0 resection(negative margins)status,adverse events,and follow-up results.Data were collected prospectively and analyzed retrospectively.RESULTS A total of 10 patients(5 males and 5 females)with an average age of 70.4±4.5 years(range:62-78 years)were enrolled in this study.Five patients were diagnosed with gastric cancer.The remaining 5 patients were diagnosed with early-stage colon cancer.The mean tumor diameter was 23.8±11.6 mm(range:15-36 mm).The NEWS procedure was successful in all cases.The mean procedure time was 111.5±10.7 min(range:80-145 min).The OSNA assay revealed no LN metastases in any patients.Histologically complete resection(R0)was achieved in 9 patients(90.0%).There was no recurrence during the follow-up period.CONCLUSION NEWS combined with sentinel LN biopsy and OSNA assay is an effective and safe technique for the removal of selected early gastric and colon cancers in which it is not possible to adopt conventional endoscopic resection techniques.This procedure allows clinicians to acquire additional information on the LN status intraoperatively.
文摘Current histopathological staging procedures in colorectal cancer(CRC)depend on midline division of the lymph nodes(LNs)with one section of hematoxylin and eosin staining.Cancer cells outside this transection line may be missed,which could lead to understaging of Union for International Cancer Control Stage II high-risk patients.The one-step nucleic acid amplification(OSNA)assay has emerged as a rapid molecular diagnostic tool for LN metastases detection.It is a molecular technique that can analyze the entire LN tissue using a reversetranscriptase loop-mediated isothermal amplification reaction to detect tumorspecific cytokeratin 19 mRNA.Our findings suggest that the OSNA assay has a high diagnostic accuracy in detecting metastatic LNs in CRC and a high negative predictive value.OSNA is a standardized,observer-independent technique,which may lead to more accurate staging.It has been suggested that in stage II CRC,the upstaging can reach 25%and these patients can access postoperative adjuvant chemotherapy.Moreover,intraoperative OSNA sentinel node evaluation may allow early CRC to be treated with organ-preserving surgery,while in more advanced-stage disease,a tailored lymphadenectomy can be performed considering the presence of aberrant lymphatic drainage and skip metastases.
基金supported by the National Key Research and Development Program of China(Nos.2023YFC2307305,2021YFF0703300)the Shenzhen Medical Research Fund(No.B2303003)+3 种基金Shenzhen Research Funding Program(Nos.JCYJ20220818102014028,RCBS20210609104339043)National Natural Science Foundation of China(No.22174167)Guangdong Basic and Applied Basic Research(No.2024A1515011281)Fundamental Research Funds for the Central Universities(No.24qnpy087)from Sun Yat-sen University。
文摘Ultrasensitive detection of nucleic acids is of great significance for precision medicine.Digital polymerase chain reaction(dPCR)is the most sensitive method but requires sophisticated and expensive instruments and a long reaction time.Digital PCR-free technologies,which mean the digital assay not relying on thermal cycling to amplify the signal for quantitative detection of nucleic acids at the singlemolecule level,include the digital isothermal amplification techniques(d IATs)and the digital clustered regularly interspaced short palindromic repeats(CRISPR)technologies.They combine the advantages of d PCR and IATs,which could be fast and simple,enabling absolute quantification of nucleic acids at a single-molecule level with minimum instrument,representing the next-generation molecular diagnostic technology.Herein,we systematically summarized the strategies and applications of various dIATs,including the digital loop-mediated isothermal amplification(dLAMP),the digital recombinase polymerase amplification(dRPA),the digital rolling circle amplification(dRCA),the digital nucleic acid sequencebased amplification(d NASBA)and the digital multiple displacement amplification(d MDA),and evaluated the pros and cons of each method.The emerging digital CRISPR technologies,including the detection mechanism of CRISPR and the various strategies for signal amplification,are also introduced comprehensively in this review.The current challenges as well as the future perspectives of the digital PCR-free technology were discussed.
文摘Hepatitis C virus(HCV)infection represents a significant health problem and represents a heavy load on some countries like Egypt in which about 20%of the total population are infected.Initial infection is usually asymptomatic and result in chronic hepatitis that give rise to complications including cirrhosis and hepatocellular carcinoma.The management of HCV infection should not only be focus on therapy,but also to screen carrier individuals in order to prevent transmission.In the present,molecular detection and quantification of HCV genome by real time polymerase chain reaction(PCR)represent the gold standard in HCV diagnosis and plays a crucial role in the management of therapeutic regimens.However,real time PCR is a complicated approach and of limited distribution.On the other hand,isothermal DNA amplification techniques have been developed and offer molecular diagnosis of infectious dieses at point-of-care.In this review we discuss recombinase polymerase amplification technique and illustrate its diagnostic value over both PCR and other isothermal amplification techniques.
基金supported by the grant from the National Natural Science Foundation of China(Nos.61901168,61971187,61871180,82002405)Hunan Key Research and Development Program(No.2021SK2003)+1 种基金Zhuzhou Innovative City Construction Project(No.2020-020)China Postdoctoral Science Foundation(No.2018M630498)。
文摘Enterocytozoon hepatopenaei(EHP)infection has seriously affected prawn culture globally.The symptoms of the infection are not apparent,and traditional detection methods are time consuming and low in accuracy.We developed a new onsite rapid testing device(size 18.8×16.7×6.6 cm^(3))for EHP based on magnesium pyrophosphate precipitation and facilitated by loop mediated isothermal amplification(LAMP).The design and fabrication of the device enables efficient light absorbance.The device has a highly sensitive detector,high-precision thermal controller,and humanized touch screen.The temperature control precision of the device is 0.2-0.3℃ at 60℃,63℃,and 65℃.The coefficients of variation values(CVV)of the luminous power in one channel at light on and off were found to be 0.0097 and 0.0014,respectively,within 1 h.The CVV of the background,luminous power,and values of eight PCR tubes filled with pure water were all less than 5%.In the EHP experiment,eight samples(including seven positive and one negative)confirmed the effectiveness of the device,and four positive and four negative samples verified whether cross-contamination exists.Among them,the rise time of the curve was about 15 min.These results assert that the developed device exhibits enhanced stability and uniformity and has excellent performance with high sensitivity,good specificity,and low testing time.Moreover,the optimal and minimum absorbance range was 555-655 nm for monitoring the production of LAMP.
基金supported by China Scholarship CouncilNIH grant to the University of Pennsylvania(No.K011K01TW011190-01A1)+1 种基金NIH grant to the University of Pennsylvania(No.R21CA228614-01A1)Beijing Hope Run Special Fund from the Cancer Foundation of China(Nos.LC2019L04 and LC2020A36)。
文摘Liquid biopsy is a highly promising method for non-invasive detection of tumor-associated nucleic acid fragments in body fluids but is challenged by the low abundance of nucleic acids of clinical interest and their sequence homology with the vast background of nucleic acids from healthy cells.Recently,programmable endonucleases such as clustered regularly interspaced short palindromic repeats(CRISPR)associated protein(Cas)and prokaryotic Argonautes have been successfully used to remove background nucleic acids and enrich mutant allele fractions,enabling their detection with deep next generation sequencing(NGS).However,the enrichment level achievable with these assays is limited by futile binding events and off-target cleavage.To overcome these shortcomings,we conceived a new assay(Programmable Enzyme-Assisted Selective Exponential Amplification,PASEA)that combines the cleavage of wild type alleles with concurrent polymerase amplification.While PASEA increases the numbers of both wild type and mutant alleles,the numbers of mutant alleles increase at much greater rates,allowing PASEA to achieve an unprecedented level of selective enrichment of targeted alleles.By combining CRISPR-Cas9 based cleavage with recombinase polymerase amplification,we converted samples with0.01%somatic mutant allele fractions(MAFs)to products with 70%MAFs in a single step within 20 min,enabling inexpensive,rapid genotyping with such as Sanger sequencers.Furthermore,PASEA's extraordinary efficiency facilitates sensitive real-time detection of somatic mutant alleles at the point of care with custom designed Exo-RPA probes.Real-time PASEA'performance was proved equivalent to clinical amplification refractory mutation system(ARMS)-PCR and NGS when testing over hundred cancer patients'samples.This strategy has the potential to reduce the cost and time of cancer screening and genotyping,and to enable targeted therapies in resource-limited settings.
基金support from The Ivan Bowen Family Foundation and the Department of Physiology and Biomedical Engineering at Mayo Clinic,Rochester MN.
文摘Nucleic acid amplification tests(NAAT)have long been used in laboratory facilities and recently revolutionized the field of molecular diagnostics in point-of-care testing.Digital microfluidics(DMF)has emerged as a promising tool to complete the entire NAAT workflow in a miniaturized format with minimum human intervention.Based on electric fields to manipulate independent reaction droplets,the compact DMF system could perform multiple processes simultaneously and automatically in a programmable fashion.This combination is beginning to establish powerful sample-to-answer platforms in remote or resource-limited settings.Herein,we provide a comprehensive overview of the state-of-the-art DMF technology for point-of-care NAAT.This review focused on key principles of DMF platforms and the latest trends in system integration for automated processes of nucleic acid extraction,amplification,and detection.Also,this article discusses current challenges,including control systems,scalability and throughput,as well as future prospects of DMF-based NAAT strategy for the next generation of point-of-care diagnostics.
基金supported by the National Natural Science Foundation of China(91427304,21434007,51573175)the Fundamental Research Funds for the Central Universities(WK3450000002,WK2060200026,WK9110000005)+4 种基金the Financial Grant from the China Postdoctoral Science Foundation(2018M630708)the National Postdoctoral Program for Innovative Talents(BX20180285)supported by the Foundations of Educational Committee of Anhui Province(KJ2019A0719)the Excellent Talent Foundation of Education Department of Anhui Province(gxyq2019066)the 136 Talent Plan of Hefei Normal University
文摘Signal amplification is an important issue in DNA nanotechnology and molecular diagnostics.In this work,we report a strategy for the catalytic self-assembly of spherical nucleic acids(SNAs)programmed by two-layer cascaded DNA circuits through integrating an entropy-driven catalytic network,a catalytic hairpin assembly circuit,and a facile SNA assembly-based reporter system.This integrated system could implement^100,000-fold signal amplification in the presence of 1 pM of input target.Possessing powerful amplification ability of nucleic acid signal,our strategy should be of great potential in fabricating more robust dynamic networks to be applied for signal transduction,DNA computing,and nucleic acid-based diagnostics.
基金supported by the National Major Science and Technology Project(2018ZX10101001)to Z.Z.
文摘Background Resource-limited regions face a greater burden of infectious diseases due to limited access to molecular tests,complicating timely diagnosis and management.Current molecular point-of-care tests(POCTs)either come with high costs or lack adequate sensitivity and specificity.To facilitate better prevention and control of infectious diseases in underserved areas,we seek to address the need for molecular POCTs that better align with the World Health Organization(WHO)’s ASSURED criteria—Affordable,Sensitive,Specific,User-friendly,Rapid and robust,Equipment-free,and Deliverable to end users.Methods A novel molecular POCT,Pasteur Pipette-assisted isothermal probe amplification(pp-IPA),was developed for malaria detection.Without any microfluidics,this method capturesPlasmodium 18S rRNA in a modified Pasteur pipette using tailed genus-specific probes.After washing,the bound tailed probes are ligated to form a template for subsequent novel isothermal probe amplification using a pair of generic primers,bypassing nucleic acid extraction and reverse transcription.The method was assessed using culturedPlasmodium and compared with real-time quantitative reverse transcription PCR(RT-qPCR)or reverse transcription loop-mediated isothermal amplification(RT-LAMP)in clinical blood samples.Results The entire assay is completed in 60-80 min with minimal hands-on time,using only a Pasteur pipette and a water bath.The pp-IPA’s analytical sensitivity is 1.28×10-4 parasites/μl,with 100%specificity against various blood-borne pathogens causing malaria-like symptoms.Additionally,pp-IPA needs only liquid-transfer skill for operation and the cost is around USD 0.25 per test,making it at least 300 times lower than mainstream POCT platforms.Conclusions Designed to improve the accessibility of molecular detection in resource-limited settings,pp-IPA’s simplicity,affordability,high sensitivity/specificity,and minimal equipment requirements make it a promising point-of-care pathogen identification tool in resource-constrained regions.
基金This work was supported by the Natural Science Foundation of China(No.81,873,958,81,802,058)the National Key Research and Development Plan(No.2019YFC0840602,2020YFA0907201)+2 种基金the Guang-dong Scientific and Technological Foundation(No.2019B1515120041,2020B1111170014)the Shen-zhen Scientific and Technological Foundation(No.JCYJ20180228162336873,JCYJ20180228162321234,KCXFZ202002011007083)the China Postdoctoral Science Foundation(No.2020M670085ZX).
文摘Background:Tuberculosis(TB)remains a major threat to human health,and TB diagnostic methods remain unsatisfactory.Nucleic acid amplification tests(NAATs)show higher sensitivity compared with culture for the diagnosis of pulmonary TB(PTB).However,NAATs are expensive and cannot be easily implemented outside major medical centers.To improve the sensitivity of NAATs for PTB diagnosis,we investigated the predictive factors that might optimize NAAT utilization.Methods:A total of 1263 patients with suspected PTB were enrolled for evaluation.The sensitivity,specificity,and accuracy of methods including smear-microbiology,culture of Mtb and NAAT for Mycobacterium tuberculosis(Mtb)detection in sputum and bronchoalveolar lavage fluid samples were compared.Odds ratios and 95%confidence intervals were used to assess variables that might be associated with positive NAAT results for sputum and bronchoalveolar lavage fluid from patients with suspected PTB.Results:NAAT showed higher sensitivity for Mtb detection(61.1%)when compared with smear(9.0%)and Mtb culture(47.8%).We found that an elevated erythrocyte sedimentation rate,the presence of cavities,and positive interferon-𝛾release assay(IGRA)results were indicative of positive Mtb detection by NAAT.Moreover,individuals who had all three of these characteristics showed an 86%diagnostic positivity for PTB from Mtb detection by NAAT.Conclusions:Our study suggests that an elevated erythrocyte sedimentation rate,a positive IGRA result,and the presence of pulmonary cavities are helpful factors for predicting positive Mtb detection by NAAT.Patients with the three positive clinical markers should undergo NAAT for Mtb detection because they are the most likely individuals to be bacteriologically confirmed as having TB.
