Development of an Integrated Disposable Device for SARSCoV-2 Nucleic Acid Extraction and Detection

Objective To develop a highly sensitive and rapid nucleic acid detection method for the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Methods We designed,developed,and manufactured an integrated disposable device for SARS-CoV-2 nucleic acid extraction and detection.The precision of the liquid transfer and temperature control was tested.A comparison between our device and a commercial kit for SARS-Cov-2 nucleic acid extraction was performed using real-time fluorescence reverse transcription polymerase chain reaction(RT-PCR).The entire process,from SARS-CoV-2 nucleic acid extraction to amplification,was evaluated.Results The precision of the syringe transfer volume was 19.2±1.9μL(set value was 20),32.2±1.6(set value was 30),and 57.2±3.5(set value was 60).Temperature control in the amplification tube was measured at 60.0±0.0℃(set value was 60)and 95.1±0.2℃(set value was 95)respectively.SARS-Cov-2 nucleic acid extraction yield through the device was 7.10×10^(6) copies/mL,while a commercial kit yielded 2.98×10^(6) copies/mL.The mean time to complete the entire assay,from SARS-CoV-2 nucleic acid extraction to amplification detection,was 36 min and 45 s.The detection limit for SARS-CoV-2 nucleic acid was 250 copies/mL.Conclusion The integrated disposable devices may be used for SARS-CoV-2 Point-of-Care test(POCT).

Recent advances in living cell nucleic acid probes based on nanomaterials for early cancer diagnosis

The early diagnosis of cancer is vital for effective treatment and improved prognosis. Tumor biomarkers, which can be used for the early diagnosis, treatment, and prognostic evaluation of cancer, have emerged as a topic of intense research interest in recent years. Nucleic acid, as a type of tumor biomarker, contains vital genetic information, which is of great significance for the occurrence and development of cancer. Currently, living cell nucleic acid probes, which enable the in situ imaging and dynamic monitoring of nucleic acids, have become a rapidly developing field. This review focuses on living cell nucleic acid probes that can be used for the early diagnosis of tumors. We describe the fundamental design of the probe in terms of three units and focus on the roles of different nanomaterials in probe delivery.

A brief review of novel nucleic acid test biosensors and their application prospects for salmonids viral diseases detection

Viral diseases represent one of the major threats for salmonids aquaculture.Early detection and identification of viral pathogens is the main prerequisite prior to undertaking effective prevention and control measures.Rapid,sensitive,efficient and portable detection method is highly essential for fish viral diseases detection.Biosensor strategies are highly prevalent and fulfill the expanding demands of on-site detection with fast response,cost-effectiveness,high sensitivity,and selectivity.With the development of material science,the nucleic acid biosensors fabricated by semiconductor have shown great potential in rapid and early detection or screening for diseases at salmonids fisheries.This paper reviews the current detection development of salmonids viral diseases.The present limitations and challenges of salmonids virus diseases surveillance and early detection are presented.Novel nucleic acid semiconductor biosensors are briefly reviewed.The perspective and potential application of biosensors in the on-site detection of salmonids diseases are discussed.

Ultrathin metal-organic framework nanosheets (Cu-TCPP)-based isothermal nucleic acid amplification for food allergen detection

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.

Recent advances and perspectives of nucleic acid detection for coronavirus

The recent pneumonia outbreak caused by a novel coronavirus(SARS-CoV-2)is posing a great threat to global public health.Therefore,rapid and accurate identification of pathogenic viruses plays a vital role in selecting appropriate treatments,saving people's lives and preventing epidemics.It is important to establish a quick standard diagnostic test for the detection of the infectious disease(COVID-19)to prevent subsequent secondary spread.Polymerase chain reaction(PCR)is regarded as a gold standard test for the molecular diagnosis of viral and bacterial infections with high sensitivity and specificity.Isothermal nucleic acid amplification is considered to be a highly promising candidate method due to its fundamental advantage in quick procedure time at constant temperature without thermocycler opera-tion.A variety of improved or new approaches also have been developed.This review summarizes the currently available detection methods for coronavirus nucleic acid.It is anticipated that this will assist researchers and clinicians in developing better techniques for timely and effective detection of coro-navirus infection.

Development of Nucleic Acid Sequence-Based Amplification Assay for Detection of Macrobrachium rosenbergii Nodavirus

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.

Clinical application of combined detection of SARS-CoV-2-specific antibody and nucleic acid

BACKGROUND The global outbreak of human severe acute respiratory syndrome coronavirus(SARS-CoV)-2 infection represents an urgent need for readily available,accurate and rapid diagnostic tests.Nucleic acid testing of respiratory tract specimens for SARS-CoV-2 is the current gold standard for diagnosis of coronavirus disease 2019(COVID-19).However,the diagnostic accuracy of reverse transcription polymerase chain reaction(RT-PCR)tests for detecting SARS-CoV-2 nucleic acid may be lower than optimal.The detection of SARS-CoV-2-specific antibodies should be used as a serological non-invasive tool for the diagnosis and management of SARS-CoV-2 infection.AIM To investigate the diagnostic value of SARS-CoV-2 IgM/IgG and nucleic acid detection in COVID-19.METHODS We retrospectively analyzed 652 suspected COVID-19 patients,and 206 non-COVID-19 patients in Wuhan Integrated TCM and Western Medicine Hospital.Data on SARS-CoV-2 nucleic acid tests and serum antibody tests were collected to investigate the diagnostic value of nucleic acid RT-PCR test kits and immunoglobulin(Ig)M/IgG antibody test kits.The j2 test was used to compare differences between categorical variables.A 95%confidence interval(CI)was provided by the Wilson score method.All analyses were performed with IBM SPSS Statistics version 22.0(IBM Corp.,Armonk,NY,United States).RESULTS Of the 652 suspected COVID-19 patients,237(36.3%)had positive nucleic acid tests,311(47.7%)were positive for IgM,and 592(90.8%)were positive for IgG.There was a significant difference in the positive detection rate between the IgM and IgG test groups(P<0.001).Using the RT-PCR results as a reference,the specificity,sensitivity,and accuracy of IgM/IgG combined tests for SARS-CoV-2 infection were 98.5%,95.8%,and 97.1%,respectively.Of the 415 suspected COVID-19 patients with negative nucleic acid test results,366 had positive IgM/IgG tests with a positive detection rate of 88.2%.CONCLUSION Our data indicate that serological IgM/IgG antibody combined test had high sensitivity and specificity for the diagnosis of SARS-CoV-2 infection,and can be used in combination with RT-PCR for the diagnosis of SARS-CoV-2 infection.

Improved Nucleic Acid Spot Hybridization Technique for Detection of Potato Spindle Tuber Viroid(PSTVd)

Potato spindle tuber viroid(PSTVd)disease is one of the major diseases that threatens potato production.Therefore,an advanced,rapid and sensitive detection technology is needed to detect the disease for better control.In order to establish an easier nucleic acid spot hybridization(NASH)method,some studies were tried as the followings:(1)the pre-hybridization step of nucleic acid spot hybridization(NASH)was omitted compared with ordinary way;(2)RNA extraction(phenol extraction and Ames buffer extraction)methods were compared;(3)fixed RNA by UV lamp and oven compared with UV cross-linker;(4)hybridized the RNA in shaking incubator and so on.The results showed that RNA extracted by Ames buffer was more effective than by the phenol extraction method.Besides,the result of hybridization without pre-hybridization step was better than that with 1.5 h of pre-hybridization.The more important discovery was that the shaking incubator could replace the hybridization oven and the ordinary UV lamp could replace the UV cross-linker.After a long term repeated research and testing,a new hybridization system that could rapidly detect the PSTVd by improved NASH technique merely using common instruments and equipment was established.

Consistency Analysis of Detection Results of Two Herpes Simplex Virus (HSV) Type II Nucleic Acid Detection Kits

Objective: The objective of the study is to verify the clinical validity of the following kits with the comparative experimental analysis and evaluate whether their performance can meet the clinical requirements, i.e. Class III in vitro diagnostic reagent “Herpes Simplex Virus (HSV) Type II Nucleic Acid Detection Kit (PCR-Fluorescence Probe Method)” of Daan Gene Co., Ltd. (Daan kit for short) and “Herpes Simplex Virus (HSV) Type II Nucleic Acid Detection Kit (Fluorescence PCR Method)” of Wuhan Biot Gene Co., Ltd. (Biot kit for short). Method: In the study process, the samples were divided into positive and negative groups according to the control test results, and the clinical application performance of Daan kit and Biot kit was evaluated by comparing their test results. Results: The results show that two kits indicate the same test results, i.e. 26 positive and 107 negative samples in a total of 133 male urethral discharge samples, and 32 positive and 238 negative samples in a total of 270 female cervical secretion samples. Conclusion: It can be concluded from the clinical test that Daan and Biot Herpes Simplex Virus (HSV) Type II Nuc- leic Acid Test Kits are reliable, accurate, safe, convenient for use, stable and high-value in the clinical application.

Analysis of diagnosis and treatment of traditional Chinese medicine for COVID-19 nucleic acid

Since the outbreak of coronavirus disease 2019(COVID-19),the author has been involved in the treatment of COVID-19 in the first line.It is found that some patients had a long viral nucleic acid negative time,and even the course of the disease lasted more than 40 days.After a thorough investigation of the root causes,it is found the four possible causes were:"Blood stasis syndrome"is difficult to remove;"Damp heat"sticky greasy;Stubborn basic diseases;weak constitution.All the patients treated with traditional Chinese medicine have turned negative,and now the typical cases were analyzed and summarized in order to provide reference for the traditional Chinese medicine treatment and scientific research of the patients with COVID-19 who were difficult to turn negative.

水产品过敏原及其检测技术概述

水产品因鲜美的味道和丰富的营养而深受消费者青睐。水产品属于联合国粮农组织和世界卫生组织认定的过敏食物,其在加工、运输、贮藏过程中有可能受到外来过敏原的污染,由此引起的食品安全问题日益严峻,严重制约了行业的发展。明确水产食品中的过敏原,并利用适当的检测技术进行检测、监控,有利于预防水产食物过敏疾病的发生。本文概述水产食品中的主要过敏原,以及基于基因水平的核酸检测技术、蛋白水平的免疫检测技术及质谱检测技术研究进展,为丰富水产品过敏原及其检测手段提供理论依据。

不同核酸提取方法对HBV-DNA检测性能验证情况分析

目的评估2种乙型肝炎病毒(HBV)-DNA提取方法及2家检测试剂的性能,有助于选择优化提取试剂和检测试剂。方法2023年4月采用达安全自动核酸提取仪提取法(磁珠法)和手工提取法(一步法),并用达安和圣湘2种HBV-DNA试剂检测,对其进行精密度、正确度、线性范围、检出限及抗干扰能力等性能进行验证和评价。结果达安全自动核酸提取仪提取达安试剂检测、手工提取达安试剂检测和手工提取圣湘试剂检测在精密度、正确度、线性范围、检出限方面验证结果均达标;达安全自动核酸提取仪提取圣湘试剂检测在低值检测中变异系数大于5%,最低检测限验证不合格;抗干扰能力方面,全自动核酸提取仪提取的2.0 g/dL血红蛋白浓度的样本用达安和圣湘试剂检测结果均不受影响。手工提取甘油三酯浓度达3000 mg/dL的样本用达安和圣湘试剂检测的结果均不受影响。结论不同厂家的提取和检测试剂避免混用,达安和圣湘试剂对HBV-DNA定量检测的结果均符合要求。

核酸单反应性质量控制多规则的建立

目的探讨建立1个基于Poisson分布的监控核酸筛查实验室污染情况的质控机制。方法收集2022—2023年基立福Panther核酸检测系统的核酸单反应性率和鉴别试验反应性率相关数据,采用Poisson分布概率法计算每日核酸检测单反应性的概率,利用单反应性率和鉴别反应性率及ROC曲线分析法进一步验证该质控模型的灵敏度和特异性,并提出相应的多规则化的质控策略。结果仅以P=0.05为失控限,Poisson分布概率质控模型判定P<0.05的失控点为40个,结合鉴别反应性率进行人工验证后发现失控点为20个,其判定失控的灵敏度为60.0%,特异性为95.6%,失控点较多,结合鉴别反应性率和运用多规则化质控方法进行质量监控后,2022—2023年核酸检测单反应性警告点为18个,失控点为2个。结论基于Poisson分布概率的多规则核酸单反应性监控机制,更适用于核酸实验室监测预警实验室污染,有利于提升核酸实验室管理能力和检测质量。

早期香蕉枯萎病Foc4双探针核酸纸基检测传感器研制

为实现对早期香蕉枯萎病4号生理小种(fusarium oxysporum f.sp.cubense 4, Foc4)的准确检测,该研究提出一种基于胶体金的双探针纸基传感器。该传感器将2种不同粒径的胶体金分别与检测探针和信号增强探针结合,利用DNA探针代替抗原和抗体,形成双探针体系,通过增加信号增强探针降低检测限。基于目标序列与双探针体系的碱基互补配对形成“金标探针-目标序列-T线探针”复合物并在传感器的测试区被捕获,10 min内形成肉眼可见的目标产物,通过分析测试条带得到光强度峰面积并代入标准曲线中,实现Foc4定量检测。试验结果表明,双探针纸基传感器的检测限达到0.001 nmol/L,是传统纸基传感器的100倍,提高了检测灵敏度;在0.001~1 000.000 nmol/L范围内,Foc4浓度与测试线光强度峰面积呈线性关系;使用高浓度非互补探针进行试验干扰,发现非互补序列对检测效果基本无影响,表明该传感器具有较好的特异性;香蕉叶片Foc4检测的平均回收率为77.6%~102.3%,相对标准偏差为7.4%~7.7%。与传统形态学观察等检测方法相比,该研究提出的双探针核酸纸基检测传感器可以及时、快速、准确地判断早期Foc4的存在,具有良好的推广性和实际应用价值。

人乳头瘤病毒L1基因分型国家参考品的升级换代研制

目的 对人乳头瘤病毒(HPV)L1基因分型国家参考品升级换代,以提高基于L1检测靶区的HPV核酸(分型)试剂的质量。方法 研制包含了34种不同型别HPV L1的质粒样品。经商业化核酸检测试剂复核验证,分装组成国家参考品。采用荧光PCR法进行量值标定,并溯源至WHO第一代HPV16 DNA国际参考品。结合不同实验室的协作标定研究和适用性验证结果,确定参考品的质量标准,并进一步考察参考品的稳定性。结果 国家参考品包括34种不同型别HPV样本和5种HPV阴性病原体,型别上囊括了HPV68a和HPV68b亚型。34种不同型别HPV DNA含量为6.26~7.08 Log10 IU/mL,并要求各试剂准确性应能检出其检测范围内的所有型别且分型正确,其检出限应不高于104 IU/反应。结论 成功建立了新一代HPV L1基因分型国家参考品,用于评价L1检测靶区的HPV核酸检测试剂的质量。

核酸提取试剂盒对饲料中牛羊源性成分检测的影响

实时荧光聚合酶链反应法(荧光PCR法)是目前饲料中牛羊源性成分的定性检测中常用方法之一。为了熟练操作和掌握这个方法,使得实验室工作人员在做饲料中牛羊源性成分定性这类检测时能有一个清晰的认识,通过核酸提取试剂盒的选取及平行实验比对,对此进行了阐释。

基于核酸杂交反应的荧光生物传感器的制备及在黄曲霉毒素B_1检测中的应用

采用核酸适配体作为特异性识别元件,SYBR Green I(SGI)荧光染料为信号输出单元,构建了黄曲霉毒素B_1(AFB_1)生物传感器,并对试验条件进行了优化。优化的试验条件如下:适配体互补链与适配体的物质的量比为1.5,SGI加入量为10μL,适配体双链与SGI的作用时间为2 min,适配体与AFB_1作用时间为14 min。结果表明,在AFB_1质量浓度为0.1~1 000μg·L^(-1)时,荧光强度变化量与其质量浓度对数呈线性关系,检出限(3S/N)为0.081μg·L^(-1)。对实际玉米样品进行加标回收试验,回收率为95.2%~105%,测定值的相对标准偏差(n=7)均小于6.0%。与其他适配体传感器进行比较,该方法所构建的荧光适配体传感器对AFB_1的检测具有操作简便、检测范围宽、灵敏度高、特异性强、成本低廉等优点,适合现场快速测定。

海南地区输血传播疾病病毒核酸检测窗口期残余风险评估

目的分析11年来海南地区无偿献血人群核酸检测(NAT)结果、评估HBV、HCV和HIV的NAT检测后残余风险。方法收集本中心2012年1月-2022年12月的无偿献血者NAT检测结果数据,利用新发感染率-窗口期残余风险模型对献血者进行HBV、HCV和HIV窗口期残余风险评估。结果2012年1月-2022年12月,海南地区无偿献血者捐献的血液中,来自初次献血者的占比45.02%(522684/1161042)、重复献血者(含固定献血者)占54.98%(638358/1161042),固定献血者占30.48%(354227/1162042);NAT总阳性率为0.19%(2151/1161042);NAT检测后HBV窗口期残余风险为62.54/百万,HCV残余风险为0.431/百万,HIV残余风险为0.791/百万。结论海南地区无偿献血者开展NAT检测明显降低HCV残余风险,输血传播HBV、HCV、HIV的窗口期残余风险处于较低的水平。

基于蔬菜核酸检测实验的探究性实验教学设计

以蔬菜中维生素C积累相关基因的检测为例,探索将操作难度相对较高的RNA相关的核酸检测实验应用于本科实验教学中。实践结果表明,学生们可顺利掌握蔬菜中核糖核酸(RNA)的提取、反转录合成互补DNA(cDNA)、PCR扩增检验目的基因表达等RNA相关的实验操作技能,达到了预期的教学目标。本实验项目的实施促进了学生们对多门学科知识的融会贯通,有助于其提高发现问题和解决问题的能力并形成探索精神和创新思维。这对培养具有创新创业实践能力的复合型人才具有重要的作用。