Polydopamine-based superparamagnetic molecularly imprinted polymer nanospheres for efficient protein recognition

Operation-friendly and accurate naked-eye observation assay for fast zoonotic echinococcosis and pulmonary tuberculosis monitoring in clinics

Echinococcosis and tuberculosis are two common zoonotic diseases that can cause severe pulmonary infections. Early screening and treatment monitoring are of great significance, especially in areas with limited medical resources. Herein, we designed an operation-friendly and rapid magnetic enrichment-silver acetylene chromogenic immunoassay (Me-Sacia) to monitor the antibody. The main components included secondary antibody-modified magnetic nanoparticles (MNP-Ab2) as capture nanoparticles, specific peptide (EG95 or CFP10)-modified silver nanoparticles (AgNP-PTs) as detection nanoparticles, and alkyne-modified gold nanoflowers as chromogenic nanoparticles. Based on the magnetic separation and plasma luminescence techniques, Me-Sacia could completely replace the colorimetric assay of biological enzymes. It reduced the detection time to approximately 1 h and simplified the labor-intensive and equipment-intensive processes associated with conventional ELISA. Meanwhile, the Me-Sacia showed universality for various blood samples and intuitive observation with the naked eye. Compared to conventional ELISA, Me-Sacia lowered the detection limit by approximately 96.8 %, increased the overall speed by approximately 15 times, and improved sensitivity by approximately 7.2 %, with a 100 % specificity and a coefficient of variation (CV) of less than 15 %.

Toward nano-sized imprinted norepinephrine-derived biopolymer as artificial receptors for detecting IgG1 by surface plasmon resonance

Bio-based nanostructured molecularly imprinted polymers (nano-MIPs), also known as 'plastibodies', have a real potential to be used as alternatives to natural antibodies. These nanostructures have recently gained significant attention for diagnostic and therapeutic purposes. In this context, we have developed polynorepinephrine (PNE)-based nano-MIPs using an eco-friendly one-pot process for the sensitive and selective detection of a model biomolecule, immunoglobulin IgG1. We first investigated non-imprinted nanostructures (nano-NIPs) based on polydopamine as reference material, using DLS, SEM, and UV-Vis spectroscopy. Subsequently, PNE scaffolds were characterized, both in the form of nano-NIPs and nano-MIPs. Concerning nano-MIPs, we used the epitope-directed imprinting technology to create binding cavities using a small peptide from the constant region of IgG1 as a template. Nano-MIPs were initially immobilized on a sensing surface to assess their binding capacity via surface plasmon resonance (SPR) spectroscopy. This strategy showed very good sensitivity, outperforming planar PNE-based imprinted films while keeping a high selectivity even in complex biological matrices such as human serum. Furthermore, we confirmed the presence of selective binding sites on nano-MIPs by flowing them, along with nano-NIPs, through a microfluidic SPR system, where they interact with the covalently immobilized analyte. This approach resulted in a good imprinting factor of 4.5. Overall, this study underscores the broad potential of these nanostructures as a viable and reusable alternative to antibodies across a variety of bioanalytical, biochemical, and immunohistochemistry analysis techniques.

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.

Unlocking the Potential of Molecularly Imprinted Polydopamine in Sensing Applications

Molecularly imprinted polymers (MIPs) are synthetic receptors that mimic the specificity of biological antibody-antigen interactions. By using a "lock and key" process, MIPs selectively bind to target molecules that were used as templates during polymerization. While MIPs are typically prepared using conventional monomers, such as methacrylic acid and acrylamide, contemporary advancements have pivoted towards the functional potential of dopamine as a novel monomer. The overreaching goal of the proposed review is to fully unlock the potential of molecularly imprinted polydopamine (MIPda) within the realm of cutting-edge sensing applications. This review embarks by shedding light on the intricate tapestry of materials harnessed in the meticulous crafting of MIPda, endowing them with tailored properties. Moreover, we will cover the diverse sensing applications of MIPda, including its use in the detection of ions, small molecules, epitopes, proteins, viruses, and bacteria. In addition, the main synthesis methods of MIPda, including self-polymerization and electropolymerization, will be thoroughly examined. Finally, we will examine the challenges and drawbacks associated with this research field, as well as the prospects for future developments. In its entirety, this review stands as a resolute guiding compass, illuminating the path for researchers and connoisseurs alike.

Molecularly imprinted polymers for selective extraction/microextraction of cancer biomarkers: A review

Over recent years, great efforts have been extensively documented in top scientific journals on the development of methods for early diagnosis, treatment, and monitoring of cancers which are prevalent critical diseases with a high mortality rate among men and women. The determination of cancer biomarkers using different optimum methodologies is one of the finest options for achieving these goals with more precision, speed, and at a lower cost than traditional clinical procedures. In this regard, while focusing on specific biomarkers, molecularly imprinted technology has enabled novel diagnostic techniques for a variety of diseases. Due to the well-known advantages of molecularly imprinted polymers (MIPs), this review focuses on the current trends of MIPs-based extraction/microextraction methods, specifically targeting cancer biomarkers from various matrices. These optimized methods have demonstrated high selectivity, accuracy, sorbent reusability, extraction recovery, and low limits of detection and quantification for a variety of cancer biomarkers, which are a powerful tool to provide early diagnosis, prognosis, and treatment monitoring, with potential clinical application expected soon. This review highlights the key progress, specific modifications, and strategies used for MIP synthesis. The future perspectives for cancer biomarkers purification and determination by fabricating MIP-based techniques are also discussed.

Development of enzyme/titanate nanosheet complex coated with molecularly imprinted polydopamine for colorimetric quercetin assay

A novel hybrid material, which is an enzyme/inorganic nanosheet complex coated by molecularly imprinted polymer (MIP), was developed, and applied to colorimetric quercetin assay. First, an enzyme/inorganic nanosheet complex was prepared from horseradish peroxidase (HRP) enzyme and titanate nanosheet (TiOx), using electrostatic interactions between them in acetate buffer. In the next place, dopamine self-polymerization was performed in the presence of HRP/TiOx complex with quercetin as a template, to prepare MIP membrane onto the HRP/TiOx complex. After washing process, a new hybrid material, MIP-coated HRP/TiOx complex (MIP-HT) was obtained. MIP-HT adsorbed quercetin efficiently, compared with NIP-HT that is an HRP/TiOx complex coated with non-imprinted polydopamine. MIP-HT showed enzymatic activity for an oxidation reaction of guaiacol, which is a chromogenic substrate of HRP, whereas the enzymatic activity of NIP-HT was significantly suppressed. The amount of brown product, formed by the color reaction, reduced owing to the presence of quercetin in sample solution, and a good liner relationship was observed between the concentration of quercetin and the increment of absorbance at 470 nm. The investigation using several biomolecules indicates that MIP-HT has the ability to detect quercetin and its analogues with selectivity. Therefore, MIP-HT shows great promise as a new and attractive material for use in colorimetric assay of quercetin or quercetin analogues.

Peptide nanotube functionalized molecularly imprinted polydopamine based single-use sensor for impedimetric detection of malathion

In the present study, a peptide nanotube functionalized polydopamine (p-Dop) based molecularly imprinted (MIP) sensor system was constructed, characterized, and studied for the impedimetric sensing of an organophosphorus pesticide, malathion (MLT). Electropolymerization in the presence of a template (MLT) was utilized as a convenient and effective strategy to generate imprinted p-Dop films on peptide nanotubes (PNTs) modified graphite electrodes (PGEs). Upon the removal of template, the adsorption of MLT on the specific cavities formed in the MIP film was tracked using electrochemical impedance spectroscopy (EIS). To attain optimal sensor response, experimental conditions, such as film thickness, analyte/functional monomer ratio, and desorption/adsorption time, were analyzed. The obtained MIP(p-Dop)-PNT-PGE sensor exhibited high sensitivity for electrochemical MLT analysis with a wide dynamic detection range of 13 pg mL^-1 - 1.3 µg mL^-1 and a LOD of 1.39 pg mL^-1. The combination of a bio-inspired p-Dop-based MIP with the EIS technique allowed excellent sensitivity and selectivity toward MLT sensing which also yielded high recoveries in real samples. The success of this research strategy in real samples revealed its potential for various future environmental applications.

Design of Functional Magnetic Nanocomposites for Bioseparation

Magnetic materials have been widely used in bioseparation in recent years due to their good biocompatibility, magnetic properties, and high binding capacity. In this review, we provide a brief introduction on the preparation and bioseparation applications of magnetic materials including the synthesis and surface modification of magnetic nanoparticles as well as the preparation and applications of magnetic nanocomposites in the separation of proteins, peptides, cells, exosomes and blood. The current limitations and remaining challenges in the fabrication process of magnetic materials for bioseparation will be also detailed.

Functional Control of Peptide Amphiphile Assemblies via Modulation of Internal Cohesion and Surface Chemistry Switch

Understanding the impacts of the internal cohesion and surface chemistry of supramolecular systems on the collective behaviors in the contacts between the systems and biomolecules can greatly expand the functional diversity and adaptivity of supramolecular nanostructures. Here we show how the tuned molecular interactions modulate the morphologies and internal cohesion of peptide amphiphile (PA) self-assemblies and their resultant functions. Circular dichroism spectroscopy, fluorescence probing, atomic force and electron microscopy, along with molecular dynamics simulations, revealed that the PA self-assembly formed compact long fibers when surface charge repulsion was screened, but formed loose short fibers or micelle-like assemblies when hydrogen bonding was disrupted or hydrophobic core was enhanced. More importantly, depending on the strength of the phospholipid affinity for the cationic segment of the PA, the same internal cohesion of PA nanostructures can lead to either cell death or cell survival, providing unique insights into the design of supramolecular materials.

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.

Ligand-Free Fe3 O4 /CMCS Nanoclusters with Negative Charges for Efficient Structure-Selective Protein Adsorption

The easy and effective capture of a single protein from a complex mixture is of great significance in proteomics and diagnostics. However, adsorbing nanomaterials are commonly decorated with specific ligands through a complicated and arduous process. Fe3 O4 /carboxymethylated chitosan (Fe3 O4 /CMCS) nanoclusters are developed as a new nonligand modified strategy to selectively capture bovine hemoglogin (BHB) and other structurally similar proteins (i.e., lysozyme (LYZ) and chymotrypsin (CTP)). The ligand-free Fe3 O4 /CMCS nanoclusters, in addition to their simple and economical two-step preparation process, possess many merits, including uniform morphology, high negative charges (-27 mV), high saturation magnetization (60 emu g(-1) ), and high magnetic content (85%). Additionally, the ligand-free Fe3 O4 /CMCS nanoclusters are found to selectively capture BHB in a model protein mixture even within biological samples. The reason for selective protein capture is further investigated from nanomaterials and protein structure. In terms of nanomaterials, it is found that high negative charges are conducive to selectively adsorb BHB. In consideration of protein structure, interestingly, the ligand-free magnetic nanoclusters display a structure-selective protein adsorption capacity to efficiently capture other proteins structurally similar to BHB, such as LYZ and CTP, showing great potential of the ligand-free strategy in biomedical field.

Water-compatible magnetic imprinted nanoparticles served as solid-phase extraction sorbents for selective determination of trace 17beta-estradiol in environmental water samples by liquid chromatography

Endocrine disrupting compounds (EDCs) are a potential risk for wildlife and humans for their existence in water. The efficient extraction and clean-up steps are required before detection of low concentration levels of EDCs. In this work, a novel water-compatible magnetic molecularly imprinted nanoparticles is synthesized for the selective extraction of 17β-estradiol (E2) in environmental water samples. The preparation is carried out by introducing aldehyde groups to the surface of amino-functionalized magnetic nanoparticles through a simple one-step modification, followed by copolymerization of functional monomer gelatin and template E2 via surface imprinting technique. The gelatin with abundant active groups could not only act as functional monomer reacting with template, but also assemble covalently at the surface of magnetic nanoparticles. At the same time, gelatin would improve the water-compatibility of imprinted materials for attaining high extraction efficiency. To obtain high imprinting effect, the preparation conditions are optimized in detail using Central composite design-response surface methodology. The resultant polymers have uniform spherical shape with a shell thickness of about 8nm, stable crystalline form, and super-paramagnetic property. Meanwhile, the obtained polymers have high capacity of 12.87mgg(-1) and satisfactory selectivity to template molecule. To testify the feasibility of the magnetic imprinted polymers in sample pretreatment, a method for determination of trace E2 in environmental water samples was set up by combination of solid-phase extraction (SPE) using the prepared polymers as sorbents and HPLC for rapid isolation and determination of E2. The limit of detection of proposed method is 0.04ngmL(-1), the intra- and inter-day relative standard deviations (RSDs) are less than 4.6% and 5.7%, respectively. The recoveries of E2 from environmental water samples are in the range from 88.3% to 99.1% with the RSDs less than 7.2%.