Protein A and protein A/G coupled magnetic SiO2 microspheres for affinity purification of immunoglobulin G

Advanced protein nanobiosensors to in-situ detect hazardous material in the environment

Determining hazardous substances in the environment is vital to maintaining the safety and health of all components of society, including the ecosystem and humans. Recently, protein-based nanobiosensors have emerged as effective tools for monitoring potentially hazardous substances in situ. Nanobiosensor detection mode is a combination of particular plasmonic nanomaterials (e.g., nanoparticles, nanotubes, quantum dots, etc.), and specific bioreceptors (e.g., aptamers, antibodies, DNA, etc.), which has the benefits of high selectivity, sensitivity, and compatibility with biological systems. The role of these nanobiosensors in identifying dangerous substances (e.g., heavy metals, organic pollutants, pathogens, toxins, etc.) is discussed along with different detection mechanisms and various transduction methods (e.g., electrical, optical, mechanical, electrochemical, etc.). In addition, topics discussed include the design and construction of these sensors, the selection of proteins, the integration of nanoparticles, and their development processes. A discussion of the challenges and prospects of this technology is also included. As a result, protein nanobiosensors are introduced as a powerful tool for monitoring and improving environmental quality and community safety.

Direct Affinity Ligand Immobilization onto Bare Iron Oxide Nanoparticles Enables Efficient Magnetic Separation of Antibodies

Magnetic separation is a promising alternative to chromatography for enhancing the downstream processing (DSP) of monoclonal antibodies (mAbs). However, there is a lack of efficient magnetic particles for successful application. Aiming to fill this gap, we demonstrate the suitability of bare iron oxide nanoparticles (BION) with physical site-directed immobilization of an engineered Protein A affinity ligand (rSpA) as an innovative magnetic material. The rSpA ligand contains a short peptide tag that enables the direct and stable immobilization onto the uncoated BION surface without commonly required laborious particle activation. The resulting BION@rSpA have beneficial characteristics outperforming conventional Protein A-functionalized magnetic particles: a simple, fast, low-cost synthesis, a particle size in the nanometer range with a large effective specific surface area enabling large immunoglobulin G (IgG) binding capacity, and a high magnetophoretic velocity advantageous for fast processing. We further show rapid interactions of IgG with the easily accessible rSpA ligands. The binding of IgG to BION@rSpA is thereby highly selective and not impeded by impurity molecules in perfusion cell culture supernatant. Regarding the subsequent acidic IgG elution from BION@rSpA@IgG, we observed a hampering pH increase caused by the protonation of large iron oxide surfaces after concentrating the particles in 100 mM sodium acetate buffer. However, the pH can be stabilized by adding 50 mM glycine to the elution buffer, resulting in recoveries above 85% even at high particle concentrations. Our work shows that BION@rSpA enable efficient magnetic mAb separation and could help to overcome emerging bottlenecks in DSP.

State of the art on the separation and purification of proteins by magnetic nanoparticles

The need for excellent, affordable, rapid, reusable and biocompatible protein purification techniques is justified based on the roles of proteins as key biomacromolecules. Magnetic nanomaterials nowadays have become the subject of discussion in proteomics, drug delivery, and gene sensing due to their various abilities including rapid separation, superparamagnetism, and biocompatibility. These nanomaterials also referred to as magnetic nanoparticles (MNPs) serve as excellent options for traditional protein separation and analytical methods because they have a larger surface area per volume. From ionic metals to carbon-based materials, MNPs are easily functionalized by modifying their surface to precisely recognize and bind proteins. This review excavates state-of-the-art MNPs and their functionalizing agents, as efficient protein separation and purification techniques, including ionic metals, polymers, biomolecules, antibodies, and graphene. The MNPs could be reused and efficaciously manipulated with these nanomaterials leading to highly improved efficiency, adsorption, desorption, and purity rate. We also discuss the binding and selectivity parameters of the MNPs, as well as their future outlook. It is concluded that parameters like charge, size, core-shell, lipophilicity, lipophobicity, and surface energy of the MNPs are crucial when considering protein selectivity, chelation, separation, and purity.

Influence of Pore Size in Protein G'-Grafted Mesoporous Silica Nanoparticles as a Serum Pretreatment System for In Vitro Allergy Diagnosis

Particles with the capacity to bind to immunoglobulin G (IgG) can be used for the purification of IgG or to process clinical samples for diagnostic purposes. For in vitro allergy diagnosis, the high IgG levels in serum can interfere with the detection of allergen-specific IgE, the main diagnostic biomarker. Although commercially available, current materials present a low IgG capture capacity at large IgG concentrations or require complex protocols, preventing their use in the clinic. In this work, mesoporous silica nanoparticles are prepared with different pore sizes, to which IgG-binding protein G' is grafted. It is found that for one particular optimal pore size, the IgG capture capacity of the material is greatly enhanced. The capacity of this material to efficiently capture human IgG in a selective way (compared to IgE) is demonstrated in both solutions of known IgG concentrations as well as in complex samples, like serum, from healthy controls and allergic patients using a simple and fast incubation protocol. Interestingly, IgG removal using the best-performing material enhances in vitro IgE detection in sera from patients allergic to amoxicillin. These results highlight the great translation potential of this strategy to the clinic in the context of in vitro allergy diagnosis.

A Review of the Use of Metallic Nanoparticles as a Novel Approach for Overcoming the Stability Challenges of Blood Products: A Narrative Review from 2011-2021

PURPOSE

To obtain safe and qualified blood products (e.g., platelets, plasma, and red blood cells), various limitations such as limited shelf life (especially for platelets) and stability must be addressed. In this review study, the most commonly used metal nanomaterials (e.g., gold, silver, iron, and magnetic) reported in the literature from 2011 to 2021 were discussed owing to their unique properties, which provide exciting approaches to overcome these limitations and improve the stability, safety, and quality of blood products. Novelty: This study reviews for the first time the results of studies (from 2011 to 2021) that consider the effects of various metallic nanoparticles on the different blood products.

RESULTS

The results of this review study showed that some metallic nanoparticles are effective in improving the stability of plasma proteins. For this purpose, modified Fe₃O₄ magnetic nanoparticles and citrate-AuNPs protect albumin products against stressful situations. Also, SiO₂ microspheres and silicacoated magnetite nanoparticles are highly capable of improving IgG stability. ZnO nanoparticles also reduced thrombin production, and protein-coated GMNP nanoparticles prevented unwanted leakage of factor VIII through blood vessels. Furthermore, the stability and longevity of erythrocytes can be improved by AuNP nanoparticles and Zr-based organic nanoparticles. In addition, platelet storage time can be improved using PEGylated Au and functionalized iron oxide nanoparticles.

SUGGESTION

According to the results of this study, it is suggested that further research should be conducted on metal nanoparticles as the most promising candidates to prepare metal nanoparticles with improved properties to increase the stability of various blood products.

Negatively Charged Composite Nanofibrous Hydrogel Membranes for High-Performance Protein Adsorption

Nanofibrous materials are considered as promising candidates for fabricating high-efficiency chromatography media, which are urgently needed in protein pharmaceuticals purification and biological research, yet still face several bottlenecks. Herein, novel negatively charged composite nanofibrous hydrogel membranes (NHMs) are obtained by a facile combination of electrospinning and surface coating modification. The resulting NHMs exhibit controllable morphologies and chemical structures. Benefitting from the combined effect of the stable framework of silicon dioxide (SiO₂) nanofiber and the function layer of negatively charged hydrogel, as well as good pore connectivity among nanofibers, NHMs exhibit a high protein adsorption capacity of around 1000 mg g^-1, and are superior to the commercial cellulose fibrous adsorbent (Sartobind^®) and the reported nanofibrous membranous adsorbents. Moreover, due to their relatively stable physicochemical and mechanical properties, NHMs possess comprehensive adsorption performance, favorable resistance to acid and solvents, good selectivity, and excellent regenerability. The designed NHMs composite adsorbents are expected to supply a new protein chromatography platform for effective protein purification in biopharmaceuticals and biochemical reagents.

Tractable Method for Rapid Quality Assessment of Therapeutic Antibodies in Harvested Cell Culture Fluid based on FcγRIIIa-Immobilized Magnetic Microspheres

FcγRIIIa-binding affinity is one of the key factors to ensure the efficacy of many antitumor therapeutic antibodies, which should be monitored along with the titer, protein aggregation, and other critical quality attributes. The conventional workflow for the quality assessment of therapeutic antibodies in harvested cell culture fluid (HCCF) is time-consuming and costly nevertheless. In this study, a tractable method was established for rapid quality assessment of a HCCF sample through differentially extracting IgG with different FcγRIIIa affinity levels using FcγRIIIa-immobilized magnetic microspheres, followed by size exclusion chromatography (SEC) to determine the amount and monomer percentage of IgGs in the preceding eluate. FcγRIIIa-immobilized magnetic microspheres with polydopamine (PDA) and hydrophilic dendrimer (PAMAM) coating (denoted as Fe₃O₄@PDA@PAMAM-FcγRIIIa) were synthesized for the first time as magnetic adsorbents. The PDA cladding endowed the composites with good chemical stability in acidic elution buffer, and the PAMAM dendrimer empowered the composites of high ligand immobilization capacity and hydrophilic surface. The labile FcγRIIIa was immobilized under mild conditions. By directly applying a simple magnetic solid phase extraction procedure to treat HCCF, favored IgG species with high FcγRIIIa affinity would be selectively captured by Fe₃O₄@PDA@PAMAM-FcγRIIIa composites for subsequent SEC analysis. The monomer peak area value in SEC, which was set as the read-out of the proposed method, correlated directly with the theoretical overall quality of standard-spiked HCCF samples.

Matrices and Affinity Ligands for Antibody Purification and Corresponding Applications in Radiotherapy

Antibodies have become an important class of biological products in cancer treatments such as radiotherapy. The growing therapeutic applications have driven a demand for high-purity antibodies. Affinity chromatography with a high affinity and specificity has always been utilized to separate antibodies from complex mixtures. Quality chromatographic components (matrices and affinity ligands) have either been found or generated to increase the purity and yield of antibodies. More importantly, some matrices (mainly particles) and affinity ligands (including design protocols) for antibody purification can act as radiosensitizers or carriers for therapeutic radionuclides (or for radiosensitizers) either directly or indirectly to improve the therapeutic efficiency of radiotherapy. This paper provides a brief overview on the matrices and ligands used in affinity chromatography that are involved in antibody purification and emphasizes their applications in radiotherapy to enrich potential approaches for improving the efficacy of radiotherapy.

Silicon Nanodisk Huygens Metasurfaces for Portable and Low-Cost Refractive Index and Biomarker Sensing

Biomarker detection and bulk refractive index sensing are important across multiple industries ranging from early medical diagnosis to chemical process quality control. The bulky size, high cost, and complex architecture of existing refractive index and biomarker sensing technologies limit their use to highly skilled environments like hospitals, large food processing plants, and research labs. Here, we demonstrate a compact and inexpensive refractive index sensor based on resonant dielectric photonic nanoantenna arrays or metasurfaces. These dielectric resonances support Mie dipole and asymmetric resonances that shift with changes in their external environment. A single-wavelength transmission measurement in a portable (<250 in.³), low-cost (<$4000) sensor shows sensitivity to 1.9 × 10^-6 change in the fluid refractive index without the use of a spectrometer or other complex optics. Our sensor assembly allows for measurements using multiple metasurfaces with identical resonances or varying resonance types for enhanced diagnostics on the same chip. Furthermore, a 10 kDa culture filtrate peptide CFP-10, a marker for human tuberculosis, is detected with our sensor with 10 pM resolution. This system has the potential to enable facile, fast, and highly sensitive measurements with adequate limits of detection for personalized biomedical diagnoses.

Nonspecific interaction between plasminogen and modified magnetic iron oxide nanoparticles

The magnetic particles modified with silicon dioxide (SiO₂) and amino groups (-NH₂), as well as the magnetic particles modified with human serum albumin (HSA) were synthesized using the approaches we developed before and characterized by physico-chemical methods in this study. Plasminogen was chosen as a model protein since plasminogen plays a major role in the fibrinolytic system and plasminogen level correlates with different pathologies and conditions. For the first time it has been carried out qualitative and quantitative assessment of plasminogen nonspecific binding (noncovalent adsorption) by the particles in buffer and plasma solutions. The fibrinolytic activity of plasminogen on the surface of the particles has been measured by the aid of commercially available kits and appeared to be 28-30% of its initial value. Plasminogen desorption from the surface of particles was studied in phosphate buffer with NaCl and ε-aminocaproic acid. Despite nonspecific plasminogen binding is an undesirable process, the data obtained is valuable for further modification of particles for high-specific proteins extraction from biological fluids or transport of plasminogen by the particles. The perspectives of particles modified with SiO₂ and -NH₂, and particles modified with HSA for isolation of protein analytes and their quantitative assessment thereafter have been discussed.

Recent trends in sorbents for bioaffinity chromatography

Isolation or enrichment of biological molecules from complex biological samples is mostly a prerequisite in proteomics, genomics, and glycomics. Different techniques have been used to advance the efficiency of the purification of biological molecules. Bioaffinity chromatography is one of the most powerful technique that plays an important role in the isolation of target biological molecules by the specific interactions with ligands that are immobilized on different support materials. This review examines the recent developments in bioaffinity chromatography particularly over the past 5 years in the literature. Also properties of supports, immobilization techniques, types of binding agents, and methods used in bioaffinity chromatography applications are summarized.

Mass Spectrometry-Based Methods for Immunoglobulin G N-Glycosylation Analysis

Mass spectrometry and its hyphenated techniques enabled by the improvements in liquid chromatography, capillary electrophoresis, novel ionization, and fragmentation modes are truly a cornerstone of robust and reliable protein glycosylation analysis. Boost in immunoglobulin G (IgG) glycan and glycopeptide profiling demands for both applied biomedical and research applications has brought many new advances in the field in terms of technical innovations, sample preparation, improved throughput, and confidence in glycan structural characterization. This chapter summarizes mass spectrometry basics, focusing on IgG and monoclonal antibody N-glycosylation analysis on several complexity levels. Different approaches, including antibody enrichment, glycan release, labeling, and glycopeptide preparation and purification, are covered and illustrated with recent breakthroughs and examples from the literature omitting excessive theoretical frameworks. Finally, selected highly popular methodologies in IgG glycoanalytics such as liquid chromatography-mass spectrometry and matrix-assisted laser desorption ionization are discussed more thoroughly yet in simple terms making this text a practical starting point either for the beginner in the field or an experienced clinician trying to make sense out of the IgG glycomic or glycoproteomic dataset.

Mechanism of antibodies purification by protein A

Protein A, a major cell wall component of Staphylococcus aureus, is one of the first immunoglobulin-binding proteins that is discovered about 80 years ago. However, a great deal of development in both purification methods and application of antibodies in treatment have been done. There are many publications based on the untargeted (size exclusion, ion exchange and hydrophobic interactions) and targeted (affinity) methods by scientists in academic/industry groups. In this review, we have focused on the study of both native and engineered Protein A to understand its mechanism in the purification of antibodies. What domain of Protein A dose interact with antibody? Where are contact regions? What is the non-covalent interaction mechanism of Protein A and antibody? Does alkaline condition, in the washing step, influence on antibody structure and activity? On the other hand, the immobilization of Protein A on various sorbents such as agarose, silica, polysaccharide, polymers, and magnetic nanoparticles have investigated. Also, the application of Protein A as biosensor for detection of the antibody is discussed. We have tried to find interesting and stimulating answers to all these questions.

Separation of saccharides using fullerene-bonded silica monolithic columns via π interactions in liquid chromatography

We report on a potential method to separate sugars by using the specific interaction between fullerenes and saccharides in liquid chromatography (LC). Aromatic rings with high electron density are believed to interact strongly with saccharides due to CH–π and/or OH–π interactions. In this study, the fullerene-bonded columns were used to separate saccharides by LC under aqueous conditions. As a result, 2-aminobenzamide-labeled glucose homopolymer (Glcs) was effectively separated by both C60 and C70 columns in the range of Glc-1 to Glc-20 and high blood glucose level being retained in greater quantity. Furthermore, similar separations were identified by LC–mass spectrometry with non-labeled glucose homopolymers. Theoretical study based on molecular dynamics and DFT calculation demonstrated that a supramolecular complex of saccharide–fullerene was formed through CH–π and/or OH–π interactions, and that the interactions between saccharide and fullerene increase with the increase units of the saccharide. Additionally, the C60 column retained disaccharides containing maltose, trehalose, and sucrose. In this case, it was assumed that the retention rates were determined by the difference of the dipole moment in each saccharide. These results suggest that the dipole-induced dipole interaction was dominant, and that maltose—with the higher dipole moment—was more strongly retained compared to other disaccharides having lower dipole moment.

Recovery of immunoglobulin G from rabbit serum using κ-carrageenan-modified hybrid magnetic nanoparticles

Immunoglobulin G (IgG) has been used in the treatment of cancer, autoimmune diseases and neurological disorders, however, the current technologies to purify and recover IgG from biological media are of high-cost and time-consuming, resulting in high-cost products. In this sense, the search for cost-effective technologies to obtain highly pure and active IgG is highly required. The present work proposes a simple and efficient method for the purification and recovery of IgG from rabbit serum using magnetic iron oxide nanoparticles (magnetite, Fe₃O₄) coated with hybrid shells of a siliceous material modified with the anionic polysaccharide κ-carrageenan. Experimental parameters such as pH, contact time between the hybrid magnetic nanoparticles (HMNPs) and rabbit serum, and total protein concentration or dilution factor of serum were evaluated. The best results were achieved at pH 5.0, with a contact time of 60 min and using a rabbit serum with a total protein concentration of 4.8 mg·mL^-1. Under these conditions, it was obtained an IgG purification factor and adsorption yield onto the HMNPs of 3.0 and 90%, respectively. The desorption of IgG from the HMNPs was evaluated using two strategies: a KCl aqueous solution and buffered aqueous solutions. Comparing to the initial rabbit serum, an IgG purification factor of 2.7 with a recovery yield of 74% were obtained using a buffered aqueous solution at pH 7.0. After desorption, the secondary structure of IgG and other proteins was evaluated by circular dichroism and no changes in the secondary structure were observed, meaning that the IgG integrity is kept after the adsorption and desorption steps. In summary, the application of HMNPs in the purification of IgG from serum samples has a high potential as a new downstream platform.

Plasma/serum proteomics: depletion strategies for reducing high-abundance proteins for biomarker discovery

Plasma and serum are widely used for proteomics-based biomarker discovery. However, analysis of these biofluids is highly challenging due to the complexity and wide dynamic range of their proteomes. Notably, highly abundant proteins tend to obscure the detection of potential biomarkers that are usually of lower concentrations. Among the strategies to resolve this problem are: depletion of high-abundance proteins, enrichment of low abundant proteins of interest and prefractionation. In this review, we focus on current and emerging depletion techniques used to enhance the detection and identification of the less abundant proteins in plasma and serum. We discuss the applications and contributions of these methods to proteomics analysis of plasma and serum alongside their limitations and future perspectives.

Emerging biomaterials for downstream manufacturing of therapeutic proteins

Downstream processing is considered one of the most challenging phases of industrial manufacturing of therapeutic proteins, accounting for a large portion of the total production costs. The growing demand for therapeutic proteins in the biopharmaceutical market in addition to a significant rise in upstream titers have placed an increasing burden on the downstream purification process, which is often limited by high cost and insufficient capacities. To achieve efficient production and reduced costs, a variety of biomaterials have been exploited to improve the current techniques and also to develop superior alternatives. In this work, we discuss the significance of utilizing traditional biomaterials in downstream processing and review the recent progress in the development of new biomaterials for use in protein separation and purification. Several representative methods will be highlighted and discussed in detail, including affinity chromatography, non-affinity chromatography, membrane separations, magnetic separations, and precipitation/phase separations. STATEMENT OF SIGNIFICANCE: Nowadays, downstream processing of therapeutic proteins is facing great challenges created by the rapid increase of the market size and upstream titers, starving for significant improvements or innovations in current downstream unit operations. Biomaterials have been widely used in downstream manufacturing of proteins and efforts have been continuously devoted to developing more advanced biomaterials for the implementation of more efficient and economical purification methods. This review covers recent advances in the development and application of biomaterials specifically exploited for various chromatographic and non-chromatographic techniques, highlighting several promising alternative strategies.

Molecularly imprinted polymeric shell coated monodisperse-porous silica microspheres as a stationary phase for microfluidic boronate affinity chromatography

Molecular imprinting of cis-diol functionalized agents via boronate affinity interaction has been usually performed using nanoparticles as a support which cannot be utilized as a stationary phase in continuous microcolumn applications. In this study, monodisperse-porous, spherical silica particles in the micron-size range, with bimodal pore diameter distribution were selected as a new support for the synthesis of a molecularly imprinted boronate affinity sorbent, using a cis-diol functionalized agent as the template. A specific surface area of 158 m² /g was achieved with the imprinted sorbent by using monodisperse-porous silica microspheres containing both mesoporous and macroporous compartments as the support. High porosity originating from the macroporous compartment and sufficiently high particle size provided good column permeability to the imprinted sorbent in microcolumn applications. The mesoporous compartment provided a large surface area for the parking of imprinted molecules while the macroporous compartment facilitated the intraparticular diffusion of imprinted target within the microsphere interior. A microfluidic boronate affinity system was first constructed by using molecularly imprinted polymeric shell coated monodisperse-porous silica microspheres as a stationary phase. The synthetic route for the imprinting process, the reversible adsorption/ desorption behavior of selected target and the selectivity of imprinted sorbent in both batch and microfluidic boronate affinity chromatography systems are reported.