A squaraine dye for detection of HSA based on disassembling dimers to monomers

•Controllable antiaggregation of squaraine dyes (F-Cl) for HSA sensor was constructed by UV–vis spectra.•F-Cl showed fine specificity, especially the top class discrimination ability of HSA.•HSA destruction and site competition for clarification of detection mechanism.•Successful detection of HSA in containing urine samples.