Microwave-assisted synthesis of molecularly imprinted polymers for smartphone-based luminescent hemoglobin one-pot detection

This work introduces a novel strategy to selectively and sensitively determine Hemoglobin (Hb) using a microwave-synthesized molecularly imprinted polymer (MIP) and chemiluminescence (CL) as the detection method. Studies conducted on both MIP and non-imprinted polymer (NIP) evidenced that the MIP material exhibits a high adsorption capacity (48 µg/mg) and an imprinted factor of about 3, in addition to a selective adsorption property towards Hb in the presence of other proteins, whose structures are very similar to that of Hb. The high selectivity and sensitivity of the proposed biosensor were also assured by the CL detection, whose mechanism is based on Hb's ability to enhance luminol oxidation in an alkaline medium in the presence of hydrogen peroxide, emitting a blue light whose intensity is related to the Hb concentration. The emitted light intensities from the CL reaction, directly proportional to Hb concentration, were captured and analyzed using a smartphone and RGB Color application, avoiding the use of sophisticated equipment and facilitating the measurement process. In order to streamline and speed up the detection process, all the experimental steps including Hb adsorption on MIP_Hb, supernatant removal, CL reaction, and smartphone readout occur in a single 8-well strip. Therefore, the proposed approach offers one-pot detection for the sensitive (LOD = 0.03 µg.mL⁻¹, equivalent to 1.5 nmol.L⁻¹) and selective determination of Hb in blood samples, for biomedical or forensic applications, through a rapid, low-cost, simple, and affordable approach.