Molecularly imprinted polymers (MIPs) have emerged as powerful synthetic materials capable of selective recognition and binding of target molecules, offering broad applications in sensing, drug delivery, catalysis, and diagnostics. Conventional MIP fabrication often relies on bulk imprinting techniques that suffer from slow mass transfer, limited accessibility of binding sites, and poor reproducibility. To overcome these limitations, surface imprinting strategies have been developed to enhance surface accessibility and improve binding kinetics. In this study, we present a novel one-step approach to fabricate highly ordered arrays of surface-imprinted polymer rings using controlled evaporative self-assembly within a sphere-on-flat geometry. This method leverages the inherent “coffee-ring” effect combined with repetitive stick-slip motion of the three-phase contact line during solvent evaporation, enabling spontaneous formation of gradient concentric MIP rings with exceptional regularity over large areas.
The process begins by placing a droplet of MIP precursor solution—comprising methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, 2,4-dichlorophenoxyacetic acid (2,4-D) as a template molecule, and AIBN as a photoinitiator—between a spherical lens and a flat silicon substrate. The capillary force confines the solution, initiating a dynamic evaporation process. As solvent evaporates primarily at the edge, the contact line recedes inward while undergoing repeated pinning and depinning cycles. This leads to the sequential deposition of nonvolatile solutes into well-defined concentric rings, forming a periodic patterned structure. After complete evaporation, UV irradiation triggers polymerization and cross-linking, locking the ring patterns into a semi-interpenetrating polymer network (semi-IPN). Subsequent extraction of the 2,4-D template leaves behind complementary cavities with high specificity and affinity for the target molecule.
Atomic force microscopy (AFM) and optical microscopy confirm the precise control of ring dimensions, with center-to-center spacing decreasing from ~33.4 µm at the outermost region to ~2.P21 Antibody Protocol 4 µm near the contact center. The height of the rings also diminishes progressively, reaching as low as 5 nm at the innermost zone. These nanoscale features result in a 30% increase in effective surface area compared to planar MIP films, significantly enhancing analyte accessibility. The resulting ring-patterned MIP film is further integrated into a quartz crystal microbalance (QCM) sensor platform to evaluate its sensing performance.
Gravimetric analysis reveals that the ring-patterned MIP exhibits a resonant frequency shift of -132.USO1 Antibody Technical Information 40 ± 16.PMID:35192686 57 Hz upon exposure to 200 µg/mL 2,4-D, far exceeding the response of planar MIP (-92.53 ± 4.97 Hz) and nonimprinted control films (-57.03 ± 7.20 Hz). Sensitivity measurements show a linear response to 2,4-D concentrations ranging from 10 to 200 µg/mL, with a detection limit as low as 7.73 µg/mL. Crucially, the ring-patterned MIP demonstrates outstanding selectivity, showing minimal response to structurally similar herbicides such as atrazine, ametryn, and BA, while displaying a strong signal only for 2,4-D due to specific hydrogen bonding interactions with carboxylic acid groups in the MAA matrix.
This strategy eliminates the need for complex lithographic processes, external fields, or multistep patterning, offering a simple, cost-effective, and scalable route to fabricate high-performance molecular sensors. The integration of micro- and nanoscale patterning with molecular imprinting not only enhances sensitivity and selectivity but also opens new avenues for environmental monitoring, biomedical diagnostics, and next-generation chemical sensing platforms. The ability to generate uniform, customizable, and high-surface-area MIP structures through self-assembly represents a significant advancement in smart material design.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com