Selective pathological and intracellular detection of human serum albumin by photophysical and electrochemical techniques using a FRET-based molecular probe

A simple, easily synthesizable, low-cost, fluorescent turn-on probe is presented herein for the selective and quantitative detection of human serum albumin (HSA) in different biological fluids collected from patients with various clinical manifestations. The sensor can detect HSA level by both photophysical and electrochemical means. The developed probe is also efficient in rapid quantification of HSA level in single living cell, cell lysate and tissue extract with high sensitivity. Both higher (millimolar) and trace (micromolar) amount of serum albumin can be accurately quantified using this probe in vast array of biomedical samples. This chemical sensor is also used as a part of Förster Resonance Energy Transfer (FRET) based system adding further accuracy to the measurement technique. Intracellular concentrations of HSA can be measured as well as imaged using this newly synthesized probe. Electrochemical detection of HSA concentrations can also be achieved with this biosensor using a potentiostat. Thus, this probe offers a unique potential of diagnosing HSA levels directly in various biological samples, using its bimodal (i.e., photophysical and electrochemical) properties which is hitherto unknown till date. •Rhodamine and naphthalimide based FRET pairs were used as selective biosensor for human serum albumin (HSA).•Specific chemical reaction-based interaction makes it highly selective towards HSA.•Portable potentiostat based electrochemical detection of HSA.•High-throughput photophysical detection of HSA directly from pathological samples collected from patients.•Intracellular monitoring of HSA level inside cancer cells.