Sensitive and visible detection of apoptotic cells on Annexin-V modified substrate using aminophenylboronic acid modified gold nanoparticles (APBA-GNPs) labeling

• Annexin-V modified substrates were constructed for capture of apoptotic cells.
• Stable APBA-GNPs synthesized through a simple method were used for cell labeling.
• Silver-enhanced GNP label method was proposed for detection of apoptotic cells.
• ASV was applied to sensitive cell detection, and the detection limit was 38 apoptotic cells.
• Apoptotic cells could be discriminated from normal cells by the naked eye.

A new strategy for sensitive detection of early stage apoptosis was proposed based on silver-enhanced gold nanoparticle (GNP) label method. Annexin-V modified substrate was constructed via layer-by-layer (LBL) method for specific capture of early stage apoptotic Jurkat cells. A new kind of aminophenylboronic acid modified gold nanoparticle (APBA-GNP) was synthesized and utilized for labeling cells, followed by silver enhancement. Anodic stripping voltammetry (ASV) was applied to sensitive detection of Ag+ dissolved from the deposited silver particles, which reflected the number of cells. A good linear range from 1×102 to 3.5×103 cells was achieved, with a detection limit of 38 apoptotic cells. Moreover, the gray color of silver enhancement could be observed by the naked eye, which could be used to tell apoptotic cells apart from normal cells. Therefore, using the silver-enhanced GNP label method, apoptotic cells could not only be sensitively detected via electrochemical technique, but also can be discriminated from normal cells by the naked eye.