Recent Advances in Molecular Imprinting for Proteins on Magnetic Microspheres

The separation of proteins in biological samples plays an essential role in the development of disease detection, drug discovery, and biological analysis. Protein imprinted polymers (PIPs) serve as a tool to capture target proteins specifically and selectively from complex media for separation purposes. Whereas conventional molecularly imprinted polymer is time-consuming in terms of incubation studies and solvent removal, magnetic particles are introduced using their magnetic properties for sedimentation and separation, resulting in saving extraction and centrifugation steps. Magnetic protein imprinted polymers (MPIPs), which combine molecularly imprinting materials with magnetic properties, have emerged as a new area of research hotspot. This review provides an overview of MPIPs for proteins, including synthesis, preparation strategies, and applications. Moreover, it also looks forward to the future directions for research in this emerging field.

Fabrication of metal coordination-synergistic magnetic imprinted microspheres based on ligand-free Fe3O4-Cu for specific recognition of bovine hemoglobin

In this work, a synergistic imprinting strategy combined with metal coordination based on ligand-free Fe₃O₄-Cu was proposed to fabricate molecularly imprinted polymers (MIPs) for the recognition and isolation of bovine hemoglobin (BHb) specifically in biological samples. Copper doped magnetic microspheres prepared solvothermally in a one-pot pathway act as both magnetic core and metal affinity substrate. Upon anchoring BHb to Fe₃O₄-Cu through metal coordination, the imprinted layer was formed via dopamine self-polymerization. Profiting from the synergistic effect, the obtained imprinted microspheres exhibited an enhanced adsorption performance with the adsorption capacity of 400.86 mg g^-1, imprinting factor of 11.88, selectivity coefficient above 5.8, superior to most of other reported BHb-MIPs. Furthermore, kinetic adsorption analyses pointed to a chemisorption-limited process as described by the pseudo-second-order model, and the isothermal adsorption analyses implied monolayer adsorption, as described by the Langmuir model. In addition, the resultant magnetic MIPs can be used at least six adsorption-desorption cycles without re-incubation in the metallic salt solution, avoiding secondary environmental pollution. Furthermore, the well-defined materials showed selectivity both in individual protein samples and bovine serum, providing a promising potential in bioseparation.

Synthesis of a molecularly imprinted polymer using MOF-74(Ni) as matrix for selective recognition of lysozyme

A molecularly imprinted polymer and metal organic framework were combined to prepare protein imprinted material. MOF-74(Ni) was used as a matrix to prepare surface-imprinted material with lysozyme as a template and polydopamine as an imprinting polymer. MOF-74(Ni) not only provides a large surface area (150.0 m²/g) to modify the polymer layer with more recognition sites (Wt (Ni) = 42.24%), but also facilitates the immobilization of lysozyme by using the chelation between Ni²⁺ of the MOF-74(Ni) and protein. The thin polydopamine layer (10 nm) of the molecularly imprinted material (named MOF@PDA-MIP) enables surface imprinting. Benefiting from the thin polymer layer, MOF@PDA-MIP reached adsorption equilibrium within 10 min. The maximum adsorption capacity reaches 313.5 mg/g with the highest imprinting factor (IF) of 7.8. The specific recognition sites can distinguish target lysozyme from other proteins such as egg albumin (OVA), bovine serum albumin (BSA) and ribonuclease A (RNase A). The material was successfully applied to separation of lysozyme from egg white. Graphical abstract.

Study of horseradish peroxidase and hydrogen peroxide bi-analyte sensor with boronate affinity-based molecularly imprinted film

A novel electrochemical horseradish peroxidase (HRP) sensor was developed based on boronate affinity-based electropolymerized polythionine (PTh) molecularly imprinted polymer (MIP) as specific recognition element for HRP on gold nanoparticles (AuNPs) modified glassy carbon electrode, in which PTh acted as the electrochemical probe for the sensor. The sensor was characterized by scanning electron microscopy and electron dispersive spectroscopy. Electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry were exploited for the study of the properties of the MIP sensor. The MIP sensor exhibited excellent linear response over the range of 2.0 × 10−10 mg/mL ∼ 1.0 × 10−7 mg/mL for HRP. In addition, with MIP film as HRP immobilized matrices, the sensor for the detection of H2O2 was developed with the MIP sensor based on the reduction of H2O2 catalyzed by HRP in the presence of electron mediator PTh. The sensor showed linear relationships between the current response and H2O2 concentration from 6.0 × 10−7 to 2.0 × 10−5 mol/L. HRP and H2O2 bi-analyte sensor based on MIP film was successfully developed in this work. The developed method can also be applicable for enzyme and its enzymatic substrate bi-analyte sensor.

Fabrication of Yb3+-Immobilized Hydrophilic Phytic-Acid-Coated Magnetic Nanocomposites for the Selective Separation of Bovine Hemoglobin from Bovine Serum

In this work, Yb³⁺-immobilized hydrophilic phytic-acid-coated magnetic nanocomposites were prepared through a facile route and used to selectively separatrf bovine hemoglobin. Hydrophilic phytic acid (PA) was coated onto the magnetic Fe₃O₄-PEI via electrostatic interactions, followed by finally chelating with Yb³⁺ ions, which could produce specific protein binding sites at room temperature in water, and complex instrumentation was not necessary. The performance of as-prepared hybrids (Fe₃O₄-PEI-PA-Yb³⁺) was assessed by selectively isolating bovine hemoglobin (BHb). The obtained maximum binding capacity was 347.3 mg g^-1. The retained BHb could be eluted under simple elution via using 0.1 M of Na₂CO₃, giving a recovery of 83%. Moreover, the generation of nanocomposites was demonstrated. In addition, the PA and PEI could improve the hydrophilicity of nanoparticles and further reduce the nonspecific adsorption. Therefore, such nanocomposites were successfully employed to selectively bind and separate BHb from bovine serum as verified by SDS-PAGE and MALDI-TOF MS analysis, providing a new perspective for the isolation of heme proteins in proteomics.

Magnetic protein imprinted polymers: a review

Protein imprinted polymers have received a lot of interest in the past few years because of their applications as tailor-made receptors for biomacromolecules. Generally, the preparation of these polymers requires numerous and time-consuming steps. But their coupling with magnetic nanoparticles simplifies and speeds up the synthesis of these materials. Some recent papers describe the use of protein imprinted polymer (PIP) coupled to magnetic iron oxide nanoparticles (MION) for the design of MION@PIP biosensors. With such systems, a target protein can be specifically and selectively captured from complex media due to exceptional chemical properties of the polymer. Despite such performances, only a limited number of studies address these hybrid nanosystems. This review focuses on the chemistry and preparation of MION@PIP nanocomposites as well as on the metrics used to characterize their performances.

Synthesis of magnetic molecularly imprinted nanoparticles with multiple recognition sites for the simultaneous and selective capture of two glycoproteins

Magnetic molecularly imprinted nanoparticles with multiple recognition sites were prepared, which exhibited excellent selectivity for two glycoproteins simultaneously.

Separation of bovine hemoglobin using novel magnetic molecular imprinted nanoparticles

Magnetic molecular imprinted nanoparticles (MMIPs), combining the progressiveness of magnetic nanoparticles and surface molecular imprinting technology, have attracted increasing attention because of the high efficiency and specificity in isolation and enrichment of the target protein. This study focused on the preparation of bovine hemoglobin MMIPs with bovine hemoglobin (BHb) as the template protein and the molecular imprinted polymer covering the functional magnetic nanoparticles modified with silane and acrylic groups. The physicochemical characteristics as well as the dynamics and isothermal adsorption properties of the generated nanoparticles were investigated to determine their efficiency and specificity in the adsorption of target protein. The maximum adsorption of the target protein was 169.29 mg g⁻¹ at a specific pH, which was much larger than those obtained in some other research reports. MMIPs showed favorable selectivity towards BHb in a mixture of three different proteins. The results indicated the significant effects and broad prospects of MMIPs in the isolation and enrichment of specific proteins in the field of food, medicine and biological research.

Magnetic molecular imprinted nanoparticles (MMIPs), combining the progressiveness of magnetic nanoparticles and surface molecular imprinting technology, have shown the high efficiency and specificity in isolation and enrichment of the target protein.

Preparation of novel anionic polymeric ionic liquid materials and their potential application to protein adsorption

A series of novel anionic polymeric ionic liquid materials were prepared and used to adsorb bovine hemoglobin from bovine blood.