College of Chemical Engineering and Materials Science, Quanzhou Normal University, Quanzhou 362000, Fujian Province, China.
School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
Biosens Bioelectron. 2018 Jan 15;99:230-236. doi: 10.1016/j.bios.2017.07.067. Epub 2017 Jul 29.
Liposomes are an excellent candidate component for biosensors to transduce and amplify detection signals due to their outstanding ability in encapsulating signal marker compounds. However, the use of liposomes for photoelectrochemical (PEC) signal transduction has not yet been achieved due the lack of appropriate sensing strategy. Herein, we report on a novel liposomes-amplified PEC immunoassay (LAPIA) method for sensitive HIV-p24 antigen (p24) detection based on a split-type strategy. Initially, liposomes were encapsulated with alkaline phosphatase (ALP) in their hydrophilic chamber and conjugated with secondary antibody on the surface to form the ALP-encapsulated liposomes (ALP-Ls) based PEC signal label. Sandwiched immunoassay based on the ALP-Ls label was then carried out in microwell plate. Upon addition of tween 20, the ALP molecules were released and catalyzed the hydrolysis of ascorbic acid 2-phosphate (AA-p) to produce ascorbic acid (AA). The latter then donated electron to the graphene/g-CN nanohybrids based photoelectrode, arousing an increased photocurrent signal. The separation of immunoreaction step and PEC signal excitation (i.e. split-type) not only enabled the realization of liposomes based amplification strategy, but also could eliminate the PEC-caused biomolecules damage. The developed PEC method possessed a wide calibration range from 1.0pgmL to 50ngmL and a low detection limit of 0.63pgmL. Its practicability was demonstrated by assaying human serum samples. Moreover, the universality of the liposomes-amplified PEC sensing strategy was also demonstrated by developing it into a sensitive microRNA detection method.
脂质体由于其出色的封装信号标记化合物的能力，是生物传感器中用于转导和放大检测信号的优秀候选成分。然而，由于缺乏适当的传感策略，脂质体在光电化学（PEC）信号转导中的应用尚未实现。在此，我们基于分裂型策略，报道了一种用于敏感 HIV-p24 抗原（p24）检测的新型脂质体放大光电化学（LAPIA）免疫分析方法。首先，将碱性磷酸酶（ALP）封装在亲水性隔室中的脂质体中，并在表面上与二级抗体结合，形成基于 PEC 信号标记的 ALP 包封脂质体（ALP-Ls）。然后，在微孔板中进行基于夹心免疫测定的实验。加入吐温 20 后，ALP 分子被释放并催化抗坏血酸 2-磷酸（AA-p）的水解，生成抗坏血酸（AA）。然后，后者将电子捐赠给基于石墨烯/g-CN 纳米杂化物的光电极，引起光电流信号增加。免疫反应步骤和 PEC 信号激发（即分裂型）的分离不仅实现了基于脂质体的放大策略，而且还可以消除 PEC 引起的生物分子损伤。所开发的 PEC 方法具有从 1.0pgmL 到 50ngmL 的宽校准范围和 0.63pgmL 的低检测限。通过测定人血清样本证明了该方法的实用性。此外，通过将其开发成一种灵敏的 microRNA 检测方法，还证明了脂质体放大 PEC 传感策略的通用性。
