Segervald Jonas, Malyshev Dmitry, Öberg Rasmus, Zäll Erik, Jia Xueen, Wågberg Thomas, Andersson Magnus
Department of Physics, Umeå University, Umeå SE-901 87, Sweden.
Wallenberg Initiative Materials Science for Sustainability, Department of Physics, Umeå University, Umeå SE-901 87, Sweden.
ACS Sens. 2025 Feb 28;10(2):1237-1248. doi: 10.1021/acssensors.4c03151. Epub 2025 Jan 23.
Bacterial spores are highly resilient and capable of surviving extreme conditions, making them a persistent threat in contexts such as disease transmission, food safety, and bioterrorism. Their ability to withstand conventional sterilization methods necessitates rapid and accurate detection techniques to effectively mitigate the risks they present. In this study, we introduce a surface-enhanced Raman spectroscopy (SERS) approach for detecting spores by targeting calcium dipicolinate acid (CaDPA), a biomarker uniquely associated with bacterial spores. Our method uses probe sonication to disrupt spores, releasing their CaDPA, which is then detected by SERS on drop-dried supernatant mixed with gold nanorods. This simple approach enables the selective detection of CaDPA, distinguishing it from other spore components and background noise. We demonstrate detection of biogenic CaDPA from concentrations as low as 10 spores/mL, with sensitivity reaching beyond CaDPA levels of a single spore. Finally, we show the method's robustness by detecting CaDPA from a realistic sample of fresh milk mixed with spores. These findings highlight the potential of SERS as a sensitive and specific technique for bacterial spore detection, with implications for fields requiring rapid and reliable spore identification.
细菌孢子具有高度的复原能力，能够在极端条件下存活，这使它们在疾病传播、食品安全和生物恐怖主义等情况下构成持续威胁。它们耐受传统灭菌方法的能力使得需要快速准确的检测技术来有效降低它们所带来的风险。在本研究中，我们引入了一种表面增强拉曼光谱（SERS）方法，通过靶向吡啶二羧酸钙（CaDPA）来检测孢子，CaDPA是一种与细菌孢子唯一相关的生物标志物。我们的方法使用探针超声处理来破坏孢子，释放出它们的CaDPA，然后通过SERS在与金纳米棒混合的滴干上清液上进行检测。这种简单的方法能够选择性地检测CaDPA，将其与其他孢子成分和背景噪声区分开来。我们证明能够从低至10个孢子/毫升的浓度中检测到生物源CaDPA，灵敏度超过单个孢子的CaDPA水平。最后，我们通过从与孢子混合的新鲜牛奶实际样品中检测CaDPA来展示该方法的稳健性。这些发现凸显了SERS作为一种用于细菌孢子检测的灵敏且特异技术的潜力，对需要快速可靠的孢子鉴定的领域具有重要意义。
