Species and sex confirmation of the biological specimen play a crucial role in crime investigation. However, the specimen found in the scene is always trace quantity, which is hard to be analyzed by current methods. Moreover, the time-consuming DNA extraction, sophisticated apparatus, and complex data processing make it difficult to satisfy the demand of speediness and convenience for point-of-care tests. In this study, we first exhibit a phosphate-based visual system for field-based species and sex identification derived from trace bloodstain. By introducing phosphate ion-based colorimetry into loop-mediated isothermal amplification (LAMP) for result interpretation, not only the bloodstain can be directly submitted to mitochondrial variant amplification owing to the enhanced amplification efficiency by pyrophosphate ion hydrolyzation, but also the colorimetric signal can be recognized by the naked eye for result output within 30 min through molybdophosphate generation. Aerosol contamination, the major conflict of LAMP, has been solved once and for all by integrating uracil-DNA glycosylase into this system that still holds on a constant temperature. As a demonstration, cytochrome and Y-chromosomal amelogenin are employed to identify species and sex respectively, which has achieved a highly sensitive and specific distinguishability under a strong interferential background. Accurate results can be obtained from both the simulative degraded and dated specimen, which indicates that this novel system may serve as a promising tool in forensic practice.

中文翻译：

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基于磷酸盐介导等温放大比色系统的血迹物种和性别视觉识别

生物标本的种类和性别确认在犯罪调查中发挥着至关重要的作用。然而，现场发现的标本都是微量的，目前的方法很难对其进行分析。此外，DNA提取耗时、仪器精密、数据处理复杂，难以满足即时检测快速、便捷的需求。在这项研究中，我们首先展示了一种基于磷酸盐的视觉系统，用于基于微量血迹的野外物种和性别识别。将基于磷酸盐离子的比色法引入环介导等温扩增（LAMP）进行结果解释，由于焦磷酸离子水解提高了扩增效率，不仅可以将血迹直接提交线粒体变异体扩增，而且可以将比色信号通过生成钼磷酸盐，可在 30 分钟内得到肉眼识别的结果输出。通过将尿嘧啶-DNA 糖基化酶集成到仍保持恒温的系统中，气溶胶污染是 LAMP 的主要冲突，已得到一劳永逸的解决。举例来说，利用细胞色素和Y染色体牙釉蛋白分别进行物种和性别的识别，在强干扰背景下实现了高度灵敏和特异的区分。从模拟降解和过时的标本中都可以获得准确的结果，这表明这种新颖的系统可以作为法医学实践中的有前途的工具。