摘要/Abstract
发展了一种基于金纳米颗粒的比色传感体系用于检测前列腺特异性膜抗原的新方法.实验中合成了带有正电荷的金纳米颗粒，并设计了一段带有负电荷的前列腺特异性膜抗原的底物肽段.该方法基于金纳米颗粒聚集状态不同导致颜色变化的性质以及酶与底物的特异性识别作用，达到前列腺特异性膜抗原的检测.带正电荷的金纳米颗粒与带负电的肽段产生静电相互作用，引起金纳米颗粒的聚集；当体系中加入前列腺特异性膜抗原后，由于前列腺特异性膜抗原与肽段的特异性识别作用，带负电的肽段水解为谷氨酸碎片分子，导致金纳米颗粒的分散，反应体系颜色变化快速、明显.该方法简单、灵敏，线性范围为2～10 nmol/L，检测限为0.5 nmol/L.此外，该方法可用于标准加入法测定尿液中的PSMA.
关键词: 金纳米颗粒, 比色传感体系, 前列腺特异性膜抗原, 特异性识别, 肽段
Cancer is a major cause of death and its early diagnosis has been a research goal for many decades. For males, prostatic carcinoma has become the second leading cause of cancer death worldwide. Prostate specific membrane antigen (PSMA) has been widely recognized as a prostate cancer marker. Thus, measurement of PSMA would be more valuable for the early diagnosis of prostate cancer. Nanomaterials have the characteristics of small size effect, quantum size effect, macroscopic quantum tunneling effect and surface effect, and have been widely used in various fields, such as cell imaging, analysis and detection, drug release and treatment. Gold nanoparticles have been widely used in biosensing and medical diagnosis due to their simple preparation, high stability and unique photoelectric properties. In this paper, a new colorimetric approach is proposed for simple detection of PSMA based on gold nanoparticles. In the experiment, we synthesized gold nanoparticles with positive charges, and the polyanionic peptide as the substrate of PSMA. The detection of PSMA was based on the property that different aggregation states of gold nanoparticles can lead to the change of color and the specific recognition of PSMA for its substrate. The positively charged gold nanoparticles interact electrostatically with polyanionic peptide, resulting in aggregation of gold nanoparticles. In the presence of PSMA, however, the polyanionic peptide are hydrolyzed into glutamic acid fragment due to the reaction between the PSMA and the polyanionic peptide, resulting in the dispersion of gold nanoparticles. This behaviour leads to the development of a rapid and simple colorimetric method for assaying PSMA activity, with a detection limit of 0.5 nmol/L and the linear range of 2~10 nmol/L. This approach is simple compared to the existing ones since the gold nanoparticles-peptide based sensor is easy to be assembled and the detection can be achieved without the involvement of complicated procedures. Moreover, the applicability of the method has been demonstrated by detecting PSMA spiked into urine samples.
Key words: gold nanoparticles, colorimetric sensing system, prostate-specific membrane antigen, specific recognition, peptide
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