Enrofloxacin Molecularly Imprinted Nanofiber Membranes Made By Electrospinning And Their Applications

Enrofloxacin (ENRO), the third generation fluoroquinolones, has been widely used to treat avariety of animal and human infectious diseases. With its improper use in the veterinary clinic andanimal breeding industry, ENRO residues are likely to remain in the animal-derived food, and theirnegative effects are a big threat to human health. So, it is interesting to improve the sensitivity andthe specificity of the separation and enrichment from complex matrices.Enrofloxacin molecularly imprinted nanofiber membranes (ENRO-MINFMs) prepared byelectrospinning have both the specific adsorption capacity of the molecularly imprinted polymers(MIPs), and the large surface area and high porosity of electrospinning nanofibers, toovercome the deficiencies of the current detection technology. In this paper, we choose ENROas the template molecule to prepare the ENRO-MIPs and ENRO-MINFMs by the precipitationpolymerization and the electrospinning technique.The main contents are as follows:Enrofloxacin (ENRO) was taken as the template molecule and methacrylic acid (MAA) was takenas a functional monomer. The computational approach using quantum chemical density functionaltheory (DFT) at the B3LYP/6-31g(d,p) level were carried out to simulate the self-assembly systemof template and functional monomer. We optimized the molar ratio of ENRO and MAA bysimulating their binding energy and the optimum molar ratio of ENRO/MAA was1:4. Then, themicrospheres of the molecularly imprinted polymer (MIPs) were prepared by precipitationpolymerization using ENRO as template molecule and MAA as functional monomer. Wedetermined the optimum solvent and solvent usage via experiment. The MIPs were characterized.The results showed that MIPs microspheres were an average particle size of230nm, greater than thenon-imprinted polymeric microspheres (NIPs). Analysis of the Scatchard plot revealed that thebinding sites of MIPs to ENRO were equal class under the studied concentration range, and thedissociation constant (Kd) and apparent maximum binding capacity (Qmax) of MIPs were465.116mg/L and47.046mg/g, respectively. The adsorption quantity of MIPs to ENRO was obviouslyhigher than that of CIP and OFL, which showed better specific absorption capacity.Enrofloxacin (ENRO) molecular imprinted polymers (MIPs) obtained via precipitationpolymerization was added to the polyvinyl alcohol (PVA) aqueous solution. Then electrospinningtechnique was employed to prepare ENRO-MINFMs. We investigated the effects of concentrationof PVA solution, applied voltage, and the distance between the needle and collector on the diameter and morphology of the nanofiber membrane via scanning electron microscope (SEM) measurement.The swelling ratio, void ratio, adsorption property, and adsorption selectivity of membrane werealso studied. The optimal electrospinning process was carried out at environmental temperature of25℃and relative humidity of40%~50%, with PVA concentration of7.0wt%, spinning voltageof15kV, and the distance between the needle and collector of25cm. Under such conditions, thefibers in MINFMs were uniform with diameters of about180nm. The swelling rate and void ratioof the as-prepared MINFMs were136.76%and28.42%, respectively, which were more than thoseof non-imprinted nanofiber membranes (NINFMs). The dynamic adsorption experiments ofMINFMs showed that the adsorption reaction reached balance after300min. Analysis of theScatchard plot revealed that the binding sites of MINFMs to ENRO were equal class under thestudied concentration range, the dissociation constant (Kd) and apparent maximum adsorptionquantity (Qmax) of MINFMs were Kd=505.817mg/L and Qmax=3.862mg/g, respectively. Thespecific absorption capacity of MINFMs to ENRO was higher than those of ciprofloxacin (CIP) andofloxacin (OFL).Adding the different amounts of ENRO solution into the Milk and eggs, the recoveries of spikedsample were between80.21%and86.43%by MINFMs. It can be well applied to the actual testing.