Development of versatile sensing methods for sensitive and specific detection of clinically relevant nucleic acids and proteins is of great value for disease monitoring and diagnosis. In this work, we propose a novel isothermal Self-primer EXPonential Amplification Reaction (SPEXPAR) strategy based on a rationally engineered structure-switchable Metastable Hairpin template (MH-template). The MH-template initially keeps inactive with its self-primer overhanging a part of target recognition region to inhibit polymerization. The present targets can specifically compel the MH-template to transform into an “activate” conformation that primes a target-recyclable EXPAR. The method is simple and sensitive, can accurately and facilely detect long-chain single-stranded nucleic acids or proteins without the need of exogenous primer probes, and has a high amplification efficiency theoretically more than 2ⁿ. For a proof-of-concept demonstration, the SPEXPAR method was used to sensitively detect the characteristic sequence of the typical swine fever virus (CSFV) RNA and thrombin, as nucleic acid and protein models, with limits of detection down to 43 aM and 39 fM, respectively, and even the CSFV RNA in attenuated vaccine samples and thrombin in diluted serum samples. The SPEXPAR method may serve as a powerful technique for the biological research of single-stranded nucleic acids and proteins.

中文翻译：

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用于高灵敏度检测单链核酸和蛋白质的等温自引物指数扩增反应 (SPEXPAR)

开发用于敏感和特异性检测临床相关核酸和蛋白质的通用传感方法对于疾病监测和诊断具有重要价值。在这项工作中，我们提出了一种基于合理设计的结构可切换亚稳态发夹模板（MH 模板）的新型等温自引物指数扩增反应 (SPEXPAR) 策略。MH 模板最初保持不活动状态，其自引物悬在目标识别区域的一部分以抑制聚合。目前的目标可以专门迫使 MH 模板转变为“激活”构象，从而启动目标可回收的 EXPAR。该方法简单灵敏，无需外源引物探针即可准确、简便地检测长链单链核酸或蛋白质，^名词。对于概念验证演示，使用 SPEXPAR 方法灵敏地检测典型猪瘟病毒 (CSFV) RNA 和凝血酶的特征序列，作为核酸和蛋白质模型，检测限低至凌晨 43 点和 39 fM，甚至减毒疫苗样品中的 CSFV RNA 和稀释血清样品中的凝血酶。SPEXPAR 方法可作为单链核酸和蛋白质生物学研究的有力技术。