Dynamic light scattering immunosensor based on metal-organic framework mediated gold growth strategy for the ultra-sensitive detection of alpha-fetoprotein

Abstract The ultrasensitive detection of disease-related biomarkers is critical to improving the early diagnosis, monitoring, and treatment of diseases. Herein, we reported a dynamic light scattering (DLS)-based immunosensor for the high-sensitivity detection of alpha-fetoprotein (AFP), an important biomarker in the early diagnosis of primary liver cancer. A metal–organic framework and gold nanoparticle composite (MOF@AuNP) was designed as a low-background scattering signal probe. After its structure was decomposed in a weak alkaline solution, the numerous small-sized AuNPs (∼4 nm) were released from the MOF structure. Controllable gold in situ growth strategy without self-nucleation was then executed to increase the AuNP size. Owing to the double signal amplification of the burst release of numerous small-sized AuNPs from MOFs and the gold in situ growth for an enhanced AuNP size, the proposed DLS immunosensor was successfully applied for the ultrasensitive detection of AFP with the detection limit of 0.36 pg mL−1. The reliability of the proposed method was evaluated by analyzing 22 actual clinic serum samples, and the results were further verified by the chemiluminescence immunosensor. This work features MOF@AuNP and the gold in situ growth amplified modulation of DLS-based signal transduction, which demonstrates the great potential as a novel bioanalytical platform for a myriad of purposes.