Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom.
Biosens Bioelectron. 2013 Jan 15;39(1):21-5. doi: 10.1016/j.bios.2012.06.014. Epub 2012 Jul 6.
Insulin, a polypeptide hormone secreted by pancreatic cells, is a key regulator in glucose homeostasis. Its deficiency leads to insulin-dependent (type I) diabetes whereas resistance to insulin is common in type II diabetes, obesity and a range of endocrine disorders. Its determination is of considerable value, particularly in the clinical diagnosis of diabetes mellitus and the doping control of athletes. It has, additionally, been noted as a potential breast cancer marker (serum insulin levels being found to be raised in comparison to control patients). Electrochemical assays are potentially very cheap, highly sensitive, and very readily transposed to a point of care. Though there exist numerous examples of label free impedimetric or capacitative assaying of biomolecules, these are rarely demonstrated to be effective in complex biological mixtures or to be applicable to low molecular weight targets (since they operate through the interfacial displacement of water/ions and/or the steric blocking of a redox probe). We report herein an ultrasensitive electrochemical and label-free biosensor for insulin in blood serum with a clinically relevant linear range and detection limit of 1.2pM. The transducing surfaces, based on readily prepared, antibody modified, polyethylene glycol monolayer modified polycrystalline gold surfaces, respond in a highly specific and re-useable manner to the target in up to 50% blood serum.
胰岛素是由胰腺细胞分泌的一种多肽激素，是葡萄糖体内平衡的关键调节剂。其缺乏会导致胰岛素依赖型（I 型）糖尿病，而对胰岛素的抵抗则常见于 II 型糖尿病、肥胖症和一系列内分泌紊乱。其测定具有相当大的价值，特别是在糖尿病的临床诊断和运动员的兴奋剂控制方面。此外，它还被认为是一种潜在的乳腺癌标志物（与对照患者相比，血清胰岛素水平升高）。电化学分析具有潜在的低成本、高灵敏度和易于转化为即时检测的特点。尽管有许多关于无标记的生物分子阻抗或电容分析的例子，但这些方法很少被证明在复杂的生物混合物中有效，也不适用于低分子量的目标（因为它们是通过界面水分子/离子的置换和/或氧化还原探针的空间位阻来实现的）。我们在此报告了一种用于血清胰岛素的超灵敏电化学和无标记生物传感器，具有临床相关的线性范围和检测限为 1.2pM。基于易于制备的、抗体修饰的、聚乙二醇单层修饰的多晶金表面的转导表面以高度特异性和可重复的方式对高达 50%的血清中的目标进行响应。
