环介导等温扩增技术作为基因快速诊断方法的研究与展望

环介导等温扩增技术(LAMP)是一种新型分子诊断技术,具有灵敏度高、反应快速等优点,且仅利用简单的恒温水浴设备即可实现对特异性靶基因的高效扩增,在分子诊断领域具有巨大潜力。近几年来LAMP技术在分子诊断领域的研究非常广泛,涉及细菌、病毒、寄生虫的检测及食品转基因成分检验等诸多方面,受到越来越多学者认可,有研究者认为其可作为PCR的替补技术应用于临床基因诊断工作中。然而由于目前该技术缺乏规范化且成熟配套的上下游技术措施,如快速简单的核酸抽提技术、完善的应用体系和方案、防止交叉污染的有效措施及小型便携的检测设备等,因此在现场即时诊断领域的推广应用较为缓慢。为发挥利用LAMP技术在快速基因诊断方面的优越性,科研人员针对LAMP技术开发应用存在的问题开展了大量研究工作。立足于临床基因快速诊断的技术需求,对影响LAMP技术应用的核酸物质的快速抽提、LAMP检测体系的优化完善、结果判定、假阳性结果的规避、结果确诊及现场诊断一体化平台设计应用等领域的发展现状、需要攻克的难点及未来的应用展望进行综述,以期为未来的研究和开发指明方向,促进LAMP技术的不断完善及临床推广应用。     

新一代测序技术在临床检测中的应用

新一代测序技术在问世不到十年的时间里,大大推动了基因组学研究的发展。新一代测序技术因其高通量、快速、单碱基成本低等特点,自问世以来便广泛应用于生物学基础研究中。近年来,随着各种新测序平台和技术的成熟以及对基因组知识的积累,新一代测序技术在分子检测、临床诊断等应用研究领域也开始崭露头角。本文简要综述了新一代测序技术平台以及在肿瘤、遗传病、复杂性疾病等检测和诊断中的应用和前景。     

多重核酸检测技术研究进展

核酸检测技术因其快速、灵敏、特异、准确等优点,被广泛应用于细菌、真菌、病毒、寄生虫的快速检测和鉴定,以及疾病的早期筛查与诊断中。随着生物检测技术的发展,基于核酸的多重检测技术在核酸诊断领域发挥了越来越重要的作用,主要包括以多重PCR、核酸等温扩增、基因芯片为基础的多重核酸检测技术,这些技术可对多个靶标进行同时检测,具有快速、高通量、样品消耗少等特点。本文扼要介绍这些技术的原理,及其在病原检测、疾病诊断等方面的应用。     

宏基因组学二代测序技术在感染性呼吸系统疾病病原体诊断中的应用进展

呼吸系统感染发病率高,早期明确感染的病原体是提高治愈率、降低死亡率的关键。目前病原体培养仍是临床病原学诊断的主要方式,但其敏感性低、耗时较长,不利于早期诊断和治疗。宏基因组学测序技术具有覆盖病原体广泛、快速、无偏倚、无需特异性扩增的优势,在鉴定罕见、混合感染、免疫抑制患者感染和常规检测方法难以检测到病原体的诊断中有较高的临床应用价值;但其也有特异性较低、公认判读标准缺乏、测序结果与治疗关系不明确、耐药基因检测困难、价格较高等不足。在临床应用中,宏基因组学测序与传统微生物检测技术具有相互补充的作用,两者结合使用能够提高临床诊断效能。本文就近年来宏基因组学测序方法在临床的应用进展进行综述。     

拉曼光谱技术在病原菌感染诊断中的应用进展

快速准确诊断感染性疾病病原体是遏制超级细菌传播和抗生素滥用的重要防线。目前,临床病原菌感染诊断十分依赖于培养手段,导致检测周期长达数日,不但影响了患者的及时诊治,还间接导致抗生素的滥用。拉曼光谱技术是一种无损、高灵敏的分子指纹图谱检测技术,近年来在生物学领域得到广泛应用,其具有的免培养、快速、高特异性、低成本等优点为病原菌感染的诊断提供了新方案。本文阐述了拉曼光谱技术的原理和特点,综述了其在病原菌鉴定和抗菌药物敏感性试验方面的应用进展。     

PCR在临床淋球菌检测中的应用

ＰＣＲ多聚霉链反应技术已被广泛的应用于临床医学的多种疾病的检测诊断中,它不仅为检测病原菌提供了特异性好,敏感性强,快速简便的途径,而且还使隐性病症的早期诊断成为可能。本文仅对ＰＣＲ在淋球菌的临床检测的基本特点,应用方法以及临床样品裂解方法的改进,特异性及敏感性试验以及ＰＣＲ检测意义等做一个探讨。     

综述与专论：阿尔茨海默病体外诊断纳米技术

阿尔茨海默病(Alzheimer’s disease,AD)是一种最常见的神经退行性疾病。AD的精准诊断技术,特别是早期诊断技术是临床亟需的。近年来,以生物标志物为基础的非侵入性体外诊断技术发展迅速,特别是利用纳米材料和纳米技术的高表面活性、独特的光电特性、生物相容性好、易于表面修饰、小型化、集成化等特点,发展了新型的AD体外检测和诊断的纳米技术,大大提升了AD检测的灵敏度和准确性,并且具有简便快速等特点,在AD疾病的早期诊断、预后判断以及疗效评估等方面发挥着重要的作用。本文综述了AD蛋白质类生物标志物检测纳米技术的研究进展,介绍了纳米材料在生物标志物富集方面发挥的重要作用,阐述了以纳米材料为基础的光电信号转导技术以及增强检测信号和提高检测灵敏度的方法。除此之外,还简要介绍了AD纳米检测技术在临床诊断、预后和疗效评估方面的应用前景,总结了AD体外诊断技术的优势及面临的挑战,为AD精准诊疗研究提供参考信息。     

基于CRISPR的快速灵敏便捷分子检测

快速灵敏检测技术对疾病防控必不可少。特别是新冠疫情暴发以来,人们深刻认识到快速灵敏检测技术的重要性。近年来,以CRISPR/Cas为代表的基因编辑技术带来了生物技术革命性的进步。CRISPR的核酸检测技术因其快速、准确、灵敏、经济等特点,正在引发分子诊断革新,并已被成功应用于传染病、遗传病、肿瘤基因突变诊断,以及食品安全等领域。本文归纳了基于CRISPR的多种核酸检测体系及应用,并对未来CRISPR核酸检测发展趋势及结合人工智能的智能化检测进行了展望。     

单细胞凝胶电泳应用研究进展

单细胞凝胶电泳技术是被广泛使用的检测DNA损伤的技术,其具有灵敏度高、简便、经济、快速等各种优点。在近30年来,该技术广泛被应用于遗传毒理、环境监测、医学诊断等研究及各类实验证实方面。近些年单细胞凝胶电泳与荧光原位杂交等其他技术相结合后更是拓宽了它的应用范围,本文主要介绍了单细胞凝胶电泳的原理及优劣,并重点阐明了其在遗传毒理学、细胞凋亡、环境监测、群体生物学、临床诊断与治疗,生物信息学领域上的应用,并讨论了它的发展前景。     

纳米孔测序技术在病毒性传染病检测及研究中的应用

快速、准确鉴定出病原体是临床感染性疾病诊断和传染病预防控制的基础。高通量测序基因检测技术突破了传统检测手段的时效性、灵敏度等的局限，为病原体检测和研究提供了便捷、高效的途径。本综述以高通量测序技术发展过程为基础，回顾纳米孔三代测序技术，及其在病毒性传染病检测鉴定及研究中的应用，并对该技术的应用前景及可能存在的问题进行阐述，期望它能在病毒性传染病的防控方面发挥更大的作用。     

Tail variation of the folding primer affects the SmartAmp2 process differently

Folding primer (FP), together with turn-back primer (TP) and boost primer (BP), is one of the major components of SmartAmp2, a rapid amplification-based method for SNP detection. FP has a unique design where the annealing region is combined with a tail that can fold back. FP tails can be classified as either “strong” or “weak”, depending on the melting temperature and free energy of the hairpin structure. We report that FP tails affect the amplification process differently; by changing the FP concentration, we can increase the amplification reaction speed with “strong tails”. Unlike “strong tails”, concentration change of FP with “weak tails” did not show significant impact on the amplification speed. The comparative analyses using gel electrophoresis demonstrate that the FP type and FP ratio in the reaction change the amplification pattern. The above observations can be used to optimize the reaction and manipulate the reaction speed of SmartAmp2.     

Rapid Detection of SNP (c.309T>G) in the MDM2 Gene by the Duplex SmartAmp Method

Background

Genetic polymorphisms in the human MDM2 gene are suggested to be a tumor susceptibility marker and a prognostic factor for cancer. It has been reported that a single nucleotide polymorphism (SNP) c.309T>G in the MDM2 gene attenuates the tumor suppressor activity of p53 and accelerates tumor formation in humans.

Methodology

In this study, to detect the SNP c.309T>G in the MDM2 gene, we have developed a new SNP detection method, named “Duplex SmartAmp,” which enabled us to simultaneously detect both 309T and 309G alleles in one tube. To develop this new method, we introduced new primers i.e., nBP and oBPs, as well as two different fluorescent dyes that separately detect those genetic polymorphisms.

Results and Conclusions

By the Duplex SmartAmp method, the genetic polymorphisms of the MDM2 gene were detected directly from a small amount of genomic DNA or blood samples. We used 96 genomic DNA and 24 blood samples to validate the Duplex SmartAmp by comparison with results of the conventional PCR-RFLP method; consequently, the Duplex SmartAmp results agreed totally with those of the PCR-RFLP method. Thus, the new SNP detection method is considered useful for detecting the SNP c.309T>G in the MDM2 gene so as to judge cancer susceptibility against some cellular stress in the clinical setting, and also to handle a large number of samples and enable rapid clinical diagnosis.     

体外核酸快速扩增技术的发展和不断创新

利用聚合酶链式反应(PCR)进行的核酸体外扩增是1983年开始发展起来的一项革命性技术,目前已被广泛运用于现代化的农业和医学以及食品工业等领域,特别是在人类认知基因和基因组的过程中,体外核酸扩增技术做出了卓越的贡献。最初,体外核酸扩增技术主要是利用耐高温的DNA聚合酶(Taq酶),这样就使核酸的体外扩增反应可以在热循环中进行。但因需要使用昂贵的设备和消耗大量的电力,其成本和应用范围都受到一定的限制。之后,恒温体外核酸扩增悄然兴起,这改变了传统扩增技术的局限性,使核酸的体外扩增更加简单和方便。重组酶介导扩增(RAA)法是一种最新型的恒温体外核酸扩增技术,该系统的显著优点在于它在常温下就能实现DNA解链并快速扩增(15~30min完成),反应快速、专一性好、灵敏度高,还可用于定时定量的结果分析。     

基于微流控芯片的核酸等温扩增技术研究进展

核酸等温扩增技术是一种在恒温体系内对核酸进行高效扩增的分子扩增技术,它能够在短时间内实现目的基因的指数增长。微流控芯片(microfluidic chip)技术是把研究样品制备、核酸富集、纯化和检测等多个操作步骤集成到一块"微型化"的芯片上,经自动化处理,得出实验结果,即"样品进,结果出"。将核酸等温扩增技术与微流控芯片相结合,不仅可以实现核酸快速扩增,还可以降低对实验器材的依赖。在床边即时诊断、病原体快速筛查中具有广阔的应用前景。综合国内外相关研究报道,综述了各种等温扩增技术原理,以及基于微流控芯片的核酸等温扩增技术应用,展望了集成化微流控芯片的发展趋势和应用前景。     

Reliable amplification method for bacterial RNA

DNA microarray technology has been increasingly applied for studies of clinical samples. Frequently, RNA probes from clinical samples are available in limited amounts. We describe a reliable amplification method for bacterial RNA. We verified this method on mycobacterial RNA applying mycobacterial genome-directed primers (mtGDPs). Glass slide-based oligoarrays were employed to assess the quality of the amplification method. We observed a relatively small bias in amplified RNA pool when compared to the unamplified one. Up to 1000-fold linear RNA amplification in a single amplification round was obtained. To our knowledge, this study describes the first amplification method for mycobacterial RNA.     

Principle of LAMP method--a simple and rapid gene amplification method

So far nucleic acid test (NAT) has been employed in various fields, including infectious disease diagnoses. However, due to its complicated procedures and relatively high cost, it has not been widely utilized in many actual diagnostic applications. We have therefore developed a simple and rapid gene amplification technology, Loop-mediated Isothermal Amplification (LAMP) method, which has shown prominent results of surpassing the performance of the conventional gene amplification methods. LAMP method acquires three main features: (1) all reaction can be carried out under isothermal conditions; (2) the amplification efficiency is extremely high and tremendous amount of amplification products can be obtained; and (3) the reaction is highly specific. Furthermore, developed from the standard LAMP method, a rapid LAMP method, by adding in the loop primers, can reduce the amplification time from the previous 1 hour to less than 30 minutes. Enormous amount of white precipitate of magnesium pyrophosphate is produced as a by-product of the amplification, therefore, direct visual detection is possible without using any reaction indicators and detection equipments. We believe LAMP technology, with the integration of these features, can rightly apply to clinical genetic testing, food and environmental analysis, as well as NAT in different fields.     

核酸恒温扩增技术研究进展

核酸恒温扩增技术在生命科学研究及相关诸多领域已经得到了广泛应用。我们对核酸恒温扩增技术的最新进展作一简要综述,包括环介导恒温扩增、链替代扩增、依赖核酸序列的扩增、滚环扩增、切口酶核酸恒温扩增、依赖解旋酶的恒温扩增、转录依赖的扩增、杂交捕获法、转录介导的扩增等的原理、优缺点及应用。     

Application of nucleic acid amplification in clinical microbiology

The use of nucleic acid amplification methods in routine clinical microbiology laboratories is becoming increasingly widespread. The theory of polymerase chain reaction is described, including discussion of suitable microbal targets, extraction of nucleic acid from clinical samples, choice of primers, optimization of the process, laboratory design, contamination, and other problems as well as quality control. Other nucleic acid amplification methods such as ligase chain reaction, self-sustained sequence replication, strand displacement amplification, and branched DNA signal amplification are described and the choice of technology is discussed.     

Rapid analysis of amplified double-stranded DNA by capillary electrophoresis with laser-induced fluorescence detection

DNA amplification technology has been applied to clinical diagnosis of infectious disease, genetic disorder, and cancer. After in vitro amplification of a particular DNA region, the methods of analysis for these amplified samples play a pivotal role in clinical diagnosis. Conventional gel electrophoresis has been routinely used in the lab for checking DNA. The whole procedure is time consuming and requires more than 1 ng of DNA for detection. To achieve greater performance in DNA diagnosis, we demonstrated capillary electrophoresis with laser induced fluorescence detection for analysis of amplified DNA. The analysis of DNA could be completed within 3 min and the data is directly entered into the computer. Considering the automatic and rapid process, we believe that this method could be routinely utilized for the clinical diagnosis of amplified DNA products.