Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
ACS Sens. 2024 Feb 23;9(2):860-869. doi: 10.1021/acssensors.3c02207. Epub 2024 Jan 29.
The development of novel methodologies that can detect biomarkers from cancer or other diseases is both a challenge and a need for clinical applications. This partly motivates efforts related to nanopore-based peptide sensing. Recent work has focused on the use of gold nanoparticles for selective detection of cysteine-containing peptides. Specifically, tiopronin-capped gold nanoparticles, trapped in the cis-side of a wild-type α-hemolysin nanopore, provide a suitable anchor for the attachment of cysteine-containing peptides. It was recently shown that the attachment of these peptides onto a nanoparticle yields unique current signatures that can be used to identify the peptide. In this article, we apply this technique to the detection of ovarian cancer marker peptides ranging in length from 8 to 23 amino acid residues. It is found that sequence variability complicates the detection of low-molecular-weight peptides (<10 amino acid residues), but higher-molecular-weight peptides yield complex, high-frequency current fluctuations. These fluctuations are characterized with chi-squared and autocorrelation analyses that yield significantly improved selectivity when compared to traditional open-pore analysis. We demonstrate that the technique is capable of detecting the only two cysteine-containing peptides from LRG-1, an emerging protein biomarker, that are uniquely present in the urine of ovarian cancer patients. We further demonstrate the detection of one of these LRG-1 peptides spiked into a sample of human female urine.
开发能够从癌症或其他疾病中检测生物标志物的新方法，既是临床应用的挑战，也是需求。这在一定程度上推动了基于纳米孔的肽感测相关工作的开展。最近的工作集中在使用金纳米颗粒选择性检测含半胱氨酸的肽。具体来说，巯基脯氨酰 capped 金纳米颗粒被困在野生型α-溶血素纳米孔的顺式侧，可以为含半胱氨酸的肽的附着提供合适的锚点。最近的研究表明，这些肽附着在纳米颗粒上会产生独特的电流特征，可以用来识别肽。在本文中，我们将该技术应用于检测卵巢癌标记肽，这些肽的长度从 8 到 23 个氨基酸残基不等。研究发现，序列的可变性使低分子量肽(<10 个氨基酸残基)的检测变得复杂，但高分子量肽会产生复杂的高频电流波动。通过卡方和自相关分析对这些波动进行了特征描述，与传统的开孔分析相比，该方法显著提高了选择性。我们证明了该技术能够检测出 LRG-1 中仅有的两个含半胱氨酸的肽，LRG-1 是一种新兴的蛋白质生物标志物，仅存在于卵巢癌患者的尿液中。我们进一步证明了在人女性尿液样本中检测到的一种 LRG-1 肽的存在。
