Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585, Singapore.
Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117585, Singapore.
Anal Chem. 2017 Jun 20;89(12):6900-6906. doi: 10.1021/acs.analchem.7b01508. Epub 2017 Jun 8.
Streptococcus pneumoniae (SP) is a pathogenic bacterium and a major cause of community-acquired pneumonia that could be fatal if left untreated. Therefore, rapid and sensitive detection of SP is crucial to enable targeted treatment during SP infections. In this study, DNA tetrahedron (DNA TH) with a hollow structure is anchored on gold electrodes to construct an electrochemical immunosensor for rapid detection of pneumococcal surface protein A (PspA) peptide and SP lysate from synthetic and actual human samples. This DNA nanostructure-based immunosensor displays excellent electrochemical activity toward PspA with a sensitive linear region from 0 to 8 ng/mL of PspA peptide and a low limit of detection (LOD) of 0.218 ng/mL. In addition, this DNA-TH-based immunosensor exhibits good sensing performance toward SP lysate in a clinically relevant linear range from 5 to 100 CFU/mL with a LOD of 0.093 CFU/mL. Along with these attractive features, this electrochemical immunosensor is able to specifically recognize and detect the PspA peptide mixed with other physiologically relevant components like bovine serum albumin (BSA) and lipopolysaccharide. In addition, our sensor could detect SP lysate even when dispersed in BSA or Escherichia coli lysate. Lastly, uncultured samples from the nasal cavity, mouth, and axilla of a human subject could be successfully determined by this well-designed electrochemical immunosensor.
肺炎链球菌（SP）是一种致病细菌，也是社区获得性肺炎的主要病因，如果不加以治疗，可能会致命。因此，快速而敏感地检测 SP 对于在 SP 感染期间进行靶向治疗至关重要。在本研究中，具有中空结构的 DNA 四面体（DNA TH）被固定在金电极上，以构建用于快速检测肺炎球菌表面蛋白 A（PspA）肽和来自合成和实际人体样本的 SP 裂解物的电化学免疫传感器。这种基于 DNA 纳米结构的免疫传感器对 PspA 具有出色的电化学活性，其 PspA 肽的灵敏线性范围为 0 至 8ng/mL，检测限（LOD）为 0.218ng/mL。此外，该基于 DNA-TH 的免疫传感器对临床相关线性范围内的 SP 裂解物具有良好的传感性能，其检测限（LOD）为 0.093 CFU/mL。除了这些吸引人的特点外，这种电化学免疫传感器还能够特异性识别和检测 PspA 肽与其他生理相关成分（如牛血清白蛋白（BSA）和脂多糖）混合。此外，即使在分散在 BSA 或大肠杆菌裂解物中，我们的传感器也能够检测到 SP 裂解物。最后，通过这个精心设计的电化学免疫传感器，成功地对来自人体鼻腔、口腔和腋窝的未培养样本进行了测定。
