Rapid sub-nanomolar protein determination in serum using electropolymerized molecularly imprinted polymers (E-MIPs)

Area of Science:

• Materials Science
• Analytical Chemistry
• Biotechnology

Background:

• Antibody-based biosensors offer high sensitivity and selectivity but require lengthy preparation times (months).
• Rapid, cost-effective biosensing alternatives are crucial for applications in medical screening and diagnostics.
• Molecularly imprinted polymers (MIPs) are synthetic receptors offering stability and tunable recognition properties.

Purpose of the Study:

• To investigate electropolymerized molecularly imprinted polymers (E-MIPs) as rapid, antibody-free biosensors.
• To evaluate the selective recognition of model proteins, bovine haemoglobin (BHb) and bovine serum albumin (BSA), using E-MIPs.
• To assess the performance of E-MIPs on different screen-printed electrodes (SPEs) and in a biological matrix.

Main Methods:

• Fabrication of E-MIPs on disposable screen-printed electrodes (AT-Au and BT-Au SPEs) via electropolymerization.
• Evaluation of imprinting factor, selectivity factor, and limit of detection (LOD) for BHb.
• Testing of E-MIP sensor performance in calf serum using electrochemical impedance spectroscopy (EIS) and the Hill-Langmuir model.

Main Results:

• E-MIPs demonstrated high effectiveness for BHb recognition, with an imprinting factor of 146:1 at 1 nM and selectivity factor of 6:1 against BSA.
• Sensor sensitivity varied with SPE type; BT-Au SPE achieved sub-nanomolar sensitivity (LOD 50 pM in serum) within 10 minutes.
• Equilibrium dissociation constant (KD) for BHb E-MIP was determined to be 0.86 ± 0.11 nM.

Conclusions:

• E-MIPs provide a rapid (minutes) and effective alternative to antibodies for selective protein biosensing.
• The choice of SPE significantly impacts sensor sensitivity, with BT-Au SPE offering superior performance.
• E-MIPs show promise for protein determination in biological samples like serum with minimal sample preparation.