Steady-State and Frequency-Domain Lifetime Measurements of an Activated Molecular Imprinted Polymer Imprinted to Dipicolinic Acid

Abstract

We recently demonstrated the synthesis and fluorescence activity associated with an optical detector incorporating a molecular imprinted polymer (MIP). Steady-state and time-resolved (lifetime) fluorescence measurements were used to characterize the binding activity associated with MIP microparticles imprinted to dipicolinic acid (DPA). DPA is a unique biomarker associated with the sporulation phase of endospore-forming bacteria. Vinylic monomers were polymerized in a dimethylformamide solution containing DPA as a template. The resulting MIP was then pulverized and sorted into small microscale particles. Tests were conducted on replicate samples of biologically active cultures representing both vegetative stationary phase and sporulation phase of Bacillus subtilis in standard media. Samplers were adapted incorporating the MIP particles within a dialyzer cartridge (500 MW). The permeability of the dialyzer membrane permitted diffusion of lighter molecular weight constituents from microbial media effluents to enter the dialyzer chamber and come in contact with the MIP. Results showed dramatic (10-fold over background) steady-state fluorescence changes (as a function of excitation, emission and intensity) for samples associated with high endospore biomass (DPA), and a frequency-domain lifetime of 5.3 ns for the MIP-DPA complex.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

“…It could be argued that the increased use of MIPs in sensor development has been in part driven by developments in MIP formats, not least by the establishment of reproducible strategies for thin film, fiber and (nano)particle preparation. Optical,…”

Fluorescence anisotropy studies of molecularly imprinted polymers

“…Few research groups have studied the timeresolved fluorescence of MIPs (14,17). Wandelt et al incorporated fluorescent monomers into cAMPimprinted polymers and detected the quenching of fluorescence of the polymer itself as the cAMP bound with the MIPs (14).…”

“…The fluorescence lifetime of a fluorophore depends on the fluorophore's local environment, such as degrees of freedom, degree of rotational diffusion, or the distance between the fluorophore and the absorbing molecule (16). Few research groups have studied the timeresolved fluorescence of MIPs (14,17). Wandelt et al incorporated fluorescent monomers into cAMPimprinted polymers and detected the quenching of fluorescence of the polymer itself as the cAMP bound with the MIPs (14).…”

Energy transfer in ternary TbEDTA chelates with a series of dipicolinic acid derivatives

“…The rate of the resonance energy transfer (RET) can be expressed by equation kT(r) = (1/τD)(R0/r) 6 , where r is the distance between the donor and acceptor, R0 is a Förster distance and τD is the lifetime of donor in the absence of the energy transfer. [33] The fluorescence lifetime of dipicolinic acid is reported to be 5.3 ns in a polymer film [40]. The distance between the Tb(III) ion and the nitrogen of dpa was reported to be 2.49 Å [41], and we may use this value to approximate the donor-acceptor distance in Tb(dpa)3.…”