In vitro detection of human breast cancer cells (SK-BR3) using herceptin-conjugated liquid crystal microdroplets as a sensing platform

The present study utilizes antibody-protein interactions to develop an LC microdroplet based biosensor for naked eye detection of SK-BR3 human breast cancer cells. The herceptin antibody-conjugated LC microdroplets were fabricated using 4-cyano-4′-pentyl biphenyl (5CB) as the liquid crystalline phase and sodium dodecyl sulfate (SDS) as the surfactant. The poly (styrene-b-acrylic acid) amphiphilic block copolymer (PS-b-PA) played a role as a modifier for the liquid crystalline interfaces. The 5CB molecules in the herceptin antibody-conjugated LC microdroplets have shown an orientation transition from radial to bipolar on selective interactions with targeted SK-BR3 breast cancer cells, which are over expressed by the human epidermal growth factor receptor 2-positive (HER2). The herceptin antibody-conjugated LC microdroplets are found to be highly selective in the detection of SK-BR3 cancer cells in the presence of control cells, such as KB cancer cells and fibroblast (FB), and also in the presence of 10% human blood plasma. The interaction forces of the SK-BR3 cancer cells were only effective in causing orientation transitions in 5CB molecules in the LC microdroplets, which clearly suggested that the herceptin antibody-conjugated LC microdroplets could be used as a selective biosensor for a real-time detection of SK-BR3 cancer cells in biological fluids.