Xihui Cui

A highly-efficient imprinted magnetic nanoparticle for selective separation and detection of 17β-estradiol in milk.

In this work, we prepared molecularly imprinted polymers (MIPs) combining surface molecular imprinting technique and magnetic separation for separation and determination of 17β-estradiol (E2) from milk. During the synthesis process, the acryloyl chloride was specially used to graft double bonds on Fe3O4 nanoparticles and served as co-functional monomer cooperating with acrylamide. The morphology, structure property, and the best polymerization and adsorption conditions of the prepared magnetic nanoparticles were investigated in detail. The obtained nanomaterials displayed high adsorption capacity of 12.62mg/g, fast equilibrium time of 10min, and satisfactory selectivity for target molecule. Whats more, the MIPs was successfully applied as sorbents to specifically separate and enrich E2 from milk with a relatively high recovery (88.9-92.1%), demonstrating the potential application of the MIPs as solid phase extractant for rapid, highly-efficient, and cost-effective sample analysis.

Specific removal of protein using protein imprinted polydopamine shells on modified amino-functionalized magnetic nanoparticles

Thin imprinted shells over functionalized magnetic nanoparticles is an effective solution to weaken mass transfer resistance, achieve high binding capacity, and attain rapid separation. In this work, a simple, green, and effective approach was developed to imprint bovine serum albumin (BSA) on the surface of amino-modified Fe3O4 nanoparticles (Fe3O4@NH2) using dopamine as monomer through a two-step immobilized template strategy. The results of X-ray diffraction and vibrating sample magnetometry indicated that the as-synthesized nanomaterials exhibited high crystallinity and satisfactory superparamagnetic properties. Transmission electron microscopy and Fourier transform infrared spectroscopy of the products showed that polydopamine shells successfully attached onto Fe3O4@NH2. The polydopamine shells with a thickness of about 10 nm enable the template recognition sites to be accessed easily, and exhibit fast kinetics and high adsorption capacity in aqueous solution. Meanwhile, an excellent selectivity towards BSA has been presented when bovine hemoglobin (BHb), transferrin, and immunoglobulin G (IgG) were employed as competitive proteins. Good recovery after a reasonably mild elution and successful capture of the target protein from a real sample of bovine blood suggests its potential value in practical applications. In addition, the resultant polymers were stable and had no obvious deterioration after six adsorption–regeneration cycles. The versatility of the proposed method has also been verified by choosing four other proteins with different isoelectric points as the templates.

Novel polydopamine imprinting layers coated magnetic carbon nanotubes for specific separation of lysozyme from egg white

Novel core-shell nanocomposites, consisting of magnetic carbon nanotubes (MCNTs) core surrounded by a thin polydopamine (PDA) imprinting shell for specific recognition of lysozyme (Lyz), were fabricated for the first time. The obtained products were characterized and the results showed that the PDA layer was successfully attached onto the surface of MCNTs and the corresponding thickness of imprinting layer was just about 10nm which could enable the template access the recognition cavities easily. The polymerization conditions and adsorption performance of the resultant nanomaterials were investigated in detail. The results indicated that the obtained imprinted polymers showed fast kinetic and high affinity towards Lyz and could be used to specifically separate Lyz from real egg white. In addition, the prepared materials had excellent stability and no obvious deterioration after five adsorption-regeneration cycles. Easy preparation, rapid separation, high binding capacity, and satisfactory selectivity for the template protein make this polymer attractive in biotechnology and biosensors.

One-step preparation of magnetic imprinted nanoparticles adopting dopamine-cupric ion as a co-monomer for the specific recognition of bovine hemoglobin.

A novel magnetic core-shell polydopamine-cupric ion complex imprinted polymer was prepared in one-step through surface imprinting technology, which could specifically recognize bovine hemoglobin from the real blood samples. The polymerization conditions and adsorption performance of the resultant nanomaterials were investigated in detail. The results showed that the cupric ion played an important role in the recognition of template proteins. The saturating adsorption capacity of this kind of imprinted polymers was 2.23 times greater than those of imprinted polymers without cupric ion. The imprinting factor of the imprinted materials was as high as 4.23 for the template molecule. The selective separation bovine hemoglobin from the real blood sample is successfully applied. In addition, the prepared materials had excellent stability and no obvious deterioration after five adsorption-regeneration cycles. Easy preparation, rapid separation, high binding capacity and satisfactory selectivity for the template protein make this polymer attractive in the separation of high-abundance proteins.

Novel magnetic multi-template molecularly imprinted polymers for specific separation and determination of three endocrine disrupting compounds simultaneously in environmental water samples

In order to improve the practical applied value of molecularly imprinted polymers, a novel concept of multiple templates was introduced to prepare an original type of magnetic molecularly imprinted polymers. The magnetic multi-template molecularly imprinted polymers were obtained by selecting silica-coated magnetic nanoparticles as supporters, three endocrine disrupting compounds (17β-estradiol (E2), estriol (E3), and diethylstilbestrol (DES)) as the multi-template, and two kinds of silane coupling agents (3-aminopropyltriethoxysilane (APTES) and phenyltrimethoxysilane (PTMOS)) as bifunctional monomers for simultaneously specific recognition of E2, E3, and DES. The as-synthesized polymers possessed homogeneous imprinting shells, stable crystalline phase, and super-paramagnetic properties. Meanwhile, the imprinted nanomaterials displayed not only extraordinarily fast kinetics, but also satisfactory adsorption capacity, as well as favorable selectivity. More importantly, the prepared polymers exhibited a similar recognition performance to a physical mixture of three single-template polymers, but the synthetic procedure of the former was simplified with significant reduction in both preparation time and solvent consumption. In addition, the imprinted nanoparticles were applied as a specific adsorbent coupled with HPLC-UV for rapid isolation and determination of E2, E3, and DES simultaneously. The limits of detection (LODs) of proposed method for three target estrogens of E2, E3, and DES were 0.27, 0.19, and 0.08 ng mL−1, respectively, which were lower than that obtained by some other sample pretreatment methods followed by HPLC-UV analysis. Furthermore, the developed method was successfully applied for detection of multiple aimed estrogens in environmental water samples with satisfactory recoveries in the range of 92.3–98.6%.

Preparation of Cu(2+)-mediated magnetic imprinted polymers for the selective sorption of bovine hemoglobin.

In this work, a novel Cu(2+)-mediated core-shell bovine hemoglobin imprinted superparamagnetic polymers were synthesized. First, carboxyl group directly-functionalized Fe3O4 nanoparticles were produced by a facile one-pot hydrothermal method. Next, copper ions were introduced to chelate with carboxyl groups and further bonded with template bovine hemoglobin as co-functional monomer. Then, functional monomers 3-aminopropyltriethoxylsilane and octyltrimethoxysilane were adopted to form the thin polymer layers. Finally, after removal of the templates, the imprinting shells with specific recognition cavities for bovine hemoglobin were obtained on Fe3O4 nanoparticles. The resultant molecularly imprinted polymers have high adsorption capacity and satisfactory selectivity for bovine hemoglobin with the help of copper ions. The obtained magnetic nanomaterials were characterized by transmission electron microscopy, Fourier-transform infrared spectra, X-ray diffraction, and vibrating sample magnetometer. The measurements demonstrated that the as-synthesized nanomaterials exhibited good dispersion, high crystallinity, and satisfactory superparamagnetic properties. The feasibility of this method was further confirmed by using the imprinted nanomaterials to specifically extract bovine hemoglobin from real bovine blood samples.

Synthesis of magnetic dual‐template molecularly imprinted nanoparticles for the specific removal of two high‐abundance proteins simultaneously in blood plasma

Novel core-shell dual-template molecularly imprinted superparamagnetic nanoparticles were synthesized using bovine hemoglobin and bovine serum albumin as the templates for the efficient depletion of these two high-abundance proteins from blood plasma for the first time. The preparation process combined surface imprinting technique and a two-step immobilized template strategy. The obtained polymers were fully characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The results showed that the as-synthesized nanomaterials possessed homogeneous and thin imprinted shells with a thickness of about 5 nm, stable crystalline phase, and superparamagnetism. The binding performance of the imprinted polymers was investigated through a series of adsorption experiments, which indicated that the products had satisfactory recognition ability for bovine hemoglobin and bovine serum albumin. The resultant nanoparticles were also successfully applied to simultaneously selective removal of two proteins from a real bovine blood sample.

Facile and green synthesis of polysaccharide-based magnetic molecularly imprinted nanoparticles for protein recognition

In this study, a facile and green approach to prepare core–shell magnetic molecularly imprinted nanoparticles based on a layer-by-layer assembly and surface imprinting technique was developed. Two types of natural polysaccharides (sodium alginate and chitosan) were firstly employed as hydrophilic double-monomers to synthesize water-compatible imprinted nanomaterials via a two-step self-assembly strategy for recognizing protein ovalbumin. The obtained products exhibited a desired level of magnetic susceptibility (45.30 emu g−1), resulting in the convenient and highly efficient separation process. The imprinted layer with thickness about 8 nm was homogeneously coated on the surface of Fe3O4, which was favorable for the fast mass transfer and rapid binding kinetics. The results of adsorption experiments showed that the saturation adsorption capacity of imprinted products could reach 92.22 mg g−1 within 40 min, which illustrated the high binding capacity. Meanwhile, the imprinting factor was as high as 4.07, demonstrating the potential selectivity of the prepared products. More importantly, the test of validation suggested that the proposed strategy would be a general method for imprinting different proteins in aqueous media by virtue of the peculiarity of polysaccharides as well as the efficient preparation process.

Core–shell nano-sized magnetic molecularly imprinted solid phase extractant coupled with HPLC for the selective isolation and determination of 17β-estradiol in a lake water sample

In this work, a novel type of core–shell molecularly imprinted magnetic nanoparticles was synthesized and coupled with HPLC for the selective extraction and detection of 17β-estradiol (E2) in lake water samples. The synthesis procedure combined a surface imprinting technique and a facile sol–gel strategy. The morphology, structure, and magnetic properties of the obtained products were characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer. The adsorption properties of the prepared polymers were investigated by equilibrium rebinding, dynamic adsorption, and selective recognition experiments. The resultant imprinted nanomaterials exhibit not only good dispersibility, stable crystalline structure, and satisfactory super-paramagnetic properties, but also fast kinetics, high capacity (16.87 mg g−1), and favorable selectivity. In addition, the as-synthesized polymers show good reproducibility and could be used for at least six cycles of adsorption–desorption without obvious deterioration. The feasibility of the developed method using the obtained imprinted polymers as a SPE extractant coupled with HPLC for the selective isolation and determination of E2 from real water samples was demonstrated. The recovery of E2 in a lake water sample ranged from 94.2 to 98.3% with the relative standard deviation less than 4.3%. The combined method would greatly improve the sensitivity and expand the practicability of HPLC.