We describe the development, characterization, and biological testing of a new type of linear molecularly imprinted polymer (LMIP) designed to act as an anti-infective by blocking the quorum sensing (QS) mechanism and so abrogating the virulence of the pathogen Streptococcus pneumoniae. The LMIP is prepared (polymerized) in presence of a template molecule, but unlike in traditional molecular imprinting approaches, no cross-linker is used. This results in soluble low-molecular-weight oligomers that can act as a therapeutic agent in vitro and in vivo. The LMIP was characterized by mass spectrometry to determine its monomer composition. Fragments identified were then aligned along the peptide template by computer modeling to predict the possible monomer sequence of the LMIP. These findings provide a proof of principle that LMIPs can be used to block QS, thus setting the stage for the development of LMIPs a novel drug-discovery platform and class of materials to target Gram-positive pathogens.
The standard mechanism of molecular imprinting centers on the formation of a monomer−template complex in the prepolymerization mixture which remains trapped in the polymeric network following polymerization in the presence of a cross-linker. The release of the template leaves behind a binding site with functional groups "frozen" in a conformation complementary to the structure of the template and its analogues. Herein, we discuss the limitations of this model and present an alternative, in which imprinting is a result of dynamic interactions among the template, monomers, oligomers, and growing polymers in a solution. As a model, we have chosen the solid-phase synthesis of molecularly imprinted polymer (MIP) nanoparticles. Evidence is provided from the surface plasmon resonance-based binding analysis of MIP and "protoparticles", literature sources, and theoretical considerations. We conclude that the alternative mechanism may explain some behavioral inconsistency of the conventional model, including the impact of temperature, cross-linking, and computational molecular models, and describe some possibilities for improvement in MIP affinity and selectivity.
Enzyme-linked immunosorbent assay (ELISA) is a widely used standard method for sensitive detection of analytes of environmental, clinical or biotechnological interest. However, ELISA has clear drawbacks related to the use of relatively unstable antibodies and enzyme conjugates, and need in several steps such as washing of non-bound conjugates and adding dye reagents. Herein we introduce a new completely abiotic assay where antibodies and enzymes are replaced with fluorescent molecularly imprinted polymer nanoparticles (nanoMIPs) and target-conjugated magnetic nanoparticles, which acted as both reporter probes and binding agents. The components of the molecularly imprinted polymer nanoparticles assay (MINA) are assembled in microtiter plates fitted with magnetic inserts. We have compared performance of new magnetic assay with MIP-based ELISA for the detection of methyl parathion (MP). Both assays have shown high sensitivity toward allowing detection of MP at picomolar concentrations without any cross-reactivity against chlorpyriphos and fenthion. The fully abiotic assays were also proven to detect analyte in real samples such as tap water and milk. Unlike ELISA-based systems the novel assay required no washing steps or addition of enzyme substrates, making it more user-friendly and suitable for high throughput screening.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.