The combination of Pt with low-cost transition metal is an effective way to diminish the bulk utilization of costly Pt and to design new nanostructured materials with improved enzyme-like activity. In the present work, citric acid-functionalized platinum–nickel hollow nanospheres (CA@PtNi hNS) were synthesized through a simple one-pot wet chemical method, which involves the galvanic replacement reaction between the Ni nanoparticles and the Pt precursor that leads to the formation of hollow nanostructures. Transmission electron spectroscopic images revealed the uniformity of the CA@PtNi hNS, with an average diameter of 10.3 ± 2 nm. Moreover, zeta potential, FTIR, and XPS measurements confirmed the existence of citric acid in the CA@PtNi hNS. During synthesis, the use of citric acid not only facilitates monodispersity but also provides a negative surface charge (−11 mV) to the CA@PtNi hNS that electrostatically attracts the 3,3′,5,5′-Tetramethylbenzidine (TMB) substrate. As-prepared CA@PtNi hNS possessed excellent peroxidase-like activity due to rich Pt surfaces, large surface area, and heterogeneous interaction between Pt and Ni atoms. Furthermore, a nanozyme-linked immunosorbent assay (NLISA) for human serum albumin (HSA) detection was developed by replacing the enzyme in a standard enzyme-linked immunosorbent assay with CA@PtNi hNS. The CA@PtNi hNS based-NLISA showed sensitive detection of HSA concentrations ranging from 0 to 400 ng mL⁻¹ with a LOD of 0.19 ng mL⁻¹ and an average of 112% recovery of HSA from the spiked human plasma samples. The outcomes of the present study confirm the applicability of CA@PtNi hNS as substitutes for natural enzymes.

Pt与低成本过渡金属的结合是减少昂贵Pt大量使用和设计具有改善的类酶活性的新型纳米结构材料的有效方法。在目前的工作中，柠檬酸官能化的铂镍空心纳米球（CA @ PtNi hNS）是通过简单的一锅湿化学方法合成的，该方法涉及Ni纳米颗粒与Pt前体之间的电置换反应，从而导致中空纳米结构的形成。透射电子光谱图像显示出CA @ PtNi hNS的均匀性，平均直径为10.3±2 nm。此外，ζ电位，FTIR和XPS测量结果证实了CA @ PtNi hNS中存在柠檬酸。在合成过程中 柠檬酸的使用不仅有利于单分散性，而且还为CA @ PtNi hNS提供了负表面电荷（-11 mV），可静电吸引3,3'，5,5'-四甲基联苯胺（TMB）底物。制备的CA @ PtNi hNS由于具有丰富的Pt表面，较大的表面积以及Pt和Ni原子之间的异质相互作用而具有出色的过氧化物酶样活性。此外，通过用CA @ PtNi hNS代替标准酶联免疫吸附测定法中的酶，开发了一种用于人血清白蛋白（HSA）检测的纳米酶联免疫吸附测定法（NLISA）。基于CA @ PtNi hNS的NLISA可以灵敏地检测到0至400 ng mL的HSA浓度 制备的CA @ PtNi hNS由于具有丰富的Pt表面，较大的表面积以及Pt和Ni原子之间的异质相互作用而具有出色的过氧化物酶样活性。此外，通过用CA @ PtNi hNS代替标准酶联免疫吸附测定法中的酶，开发了一种用于人血清白蛋白（HSA）检测的纳米酶联免疫吸附测定法（NLISA）。基于CA @ PtNi hNS的NLISA可以灵敏地检测到0至400 ng mL的HSA浓度 制备的CA @ PtNi hNS由于具有丰富的Pt表面，较大的表面积以及Pt和Ni原子之间的异质相互作用而具有出色的过氧化物酶样活性。此外，通过用CA @ PtNi hNS代替标准酶联免疫吸附测定法中的酶，开发了一种用于人血清白蛋白（HSA）检测的纳米酶联免疫吸附测定法（NLISA）。基于CA @ PtNi hNS的NLISA可以灵敏地检测到0至400 ng mL的HSA浓度^-1的LOD为0.19 ng mL ^-1，从加标的人血浆样品中平均回收112％的HSA。本研究的结果证实了CA @ PtNi hNS作为天然酶的替代品的适用性。