Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, Daejeon, 305-701, Republic of Korea.
Nanoscale. 2014;6(3):1529-36. doi: 10.1039/c3nr05539f.
Enzyme-linked immunosorbent assays (ELISAs) have most widely been applied in immunoassays for several decades. However, several unavoidable limitations (e.g., instability caused by structural unfolding) of natural enzymes have hindered their widespread applications. Here, we describe a new nanohybrid consisting of Fe₃O₄ magnetic nanoparticles (MNPs) and platinum nanoparticles (Pt NPs), simultaneously immobilized on the surface of graphene oxide (GO). By synergistically integrating highly catalytically active Pt NPs and MNPs on GO whose frameworks possess high substrate affinity, the nanohybrid is able to achieve up to a 30-fold higher maximal reaction velocity (V(max)) compared to that of free GO for the colorimetric reaction of the peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), and enable rapid detection of target cancer cells. Specifically, using this new assay system, clinically important breast cancer cells are detected in a 5 min time period at room temperature with high specificity and sensitivity. The remarkably high capability to catalyze oxidation reactions could allow the nanohybrid to replace conventional peroxidase-based immunoassay systems as part of new, rapid, robust and convenient assay systems which can be widely utilized for the identification of important target molecules.
酶联免疫吸附测定（ELISA）在免疫测定中已广泛应用数十年。然而，天然酶的几个不可避免的局限性（例如结构展开引起的不稳定性）阻碍了它们的广泛应用。在这里，我们描述了一种由 Fe₃O₄ 磁性纳米粒子（MNPs）和铂纳米粒子（Pt NPs）组成的新型纳米杂化物，同时固定在氧化石墨烯（GO）的表面上。通过协同整合在 GO 上具有高底物亲和力的高度催化活性的 Pt NPs 和 MNPs，纳米杂化物能够实现高达 30 倍的最大反应速度（V(max)），与游离 GO 相比，过氧化物酶底物 3,3',5,5'-四甲基联苯胺（TMB）的比色反应，并且能够快速检测目标癌细胞。具体而言，使用这种新的检测系统，在室温下仅需 5 分钟即可高度特异性和敏感性地检测到临床上重要的乳腺癌细胞。这种显著的氧化反应催化能力使得纳米杂化物能够替代传统的基于过氧化物酶的免疫测定系统，成为新的快速、稳健和方便的测定系统的一部分，可广泛用于鉴定重要的靶分子。
