Background: Molecular imprinting is a technology used to produce artificial receptors
that simulate the molecular recognition in the nature and prepare the polymer network structure in the
presence of template molecule. Molecularly imprinted visual sensor combines the advantages of specific
recognition via molecular imprinting and fast response speed via visualization. The aims of this
paper are to prepare a portable visual sensor for Horseradish Peroxidase (HRP) recognition based on
molecularly imprinted hydrogel.
Methods: At first, HRP-imprinted polyacrylamide hydrogels with 1 mm thickness were obtained by
one-step synthesis via radical induced in-situ polymerization of acrylamide using acrylamide (AAm)
as the functional monomer, N,N'-Methylenebisacrylamide (MBA) as the crosslink agent and HRP as
the template molecule.
Results: Compared with nonimprinted hydrogels, the HRP-imprinted hydrogel sensor showed significant
color changes in response to the target HRP. This visual sensor was constructed based on 3, 3',
5, 5'- tetramethyl benzidine (TMB) - H2O2 color reaction system by HRP catalyzing to produce color
change through digital photography and image analysis (RGB system). The HRP-imprinted hydrogel
showed good response in the range of 0.001-0.5 mg/mL and had a significant specific recognition
compared to other proteins via selective test.
Conclusion: The proposed portable visual sensor could be used for qualitative and semi-quantitative
analysis of HRP with high selectivity and reasonable regeneration. The sensor has the advantages of
simple operation, low cost, no special equipment, and can be applied to serum sample with less sample
consumption and no need of sample preparation. It has wide application prospects in microfluidic
devices, biomimetic sensors, flexible biosensor and membrane separation technology.