Nanoparticle Biomolecular Corona-Based Enrichment of Plasma Glycoproteins for N-Glycan Profiling and Application in Biomarker Discovery

Surface-engineered nanobeads for regioselective antibody binding: A robust immunoassay platform leveraging catalytic signal amplification

Regulating protein interactions and protein corona formation of nanomaterials is crucial for advancing nanomedicine, where surface engineering of nanomaterials plays a pivotal role in precise control over biological interactions. Here, we present a surface-engineered nanoparticle-based immunoassay platform using carboxyl-enriched polystyrene nanobeads (CEPS) with regioselectively controlled antibody-binding properties. Proteomic analysis and theoretical simulation revealed that CEPS has an enhanced Fc-specific binding affinity for immunoglobulins compared to conventional carboxylated polystyrene beads, with a higher surface carboxyl density critically mediating protein interactions. This regioselective antibody binding with unique Fc-specific affinity eliminates the need for complex surface modifications, streamlining the assay process and broadening the applicability across various immunoassay formats. Additionally, incorporating a palladium catalyst within CEPS enables solvent-triggered on-demand catalytic signal amplification using a leucodye substrate, providing a more stable alternative to enzyme-based methods while significantly enhancing detection sensitivity and stability. The platform demonstrated enhanced performance in detecting clinically relevant biomarkers, including C-reactive protein, interferon-gamma, and the receptor-binding domain of SARS-CoV2, achieving lower detection limits and faster response times compared to conventional enzyme-based ELISA systems. Notably, the CEPS-based assay retained catalytic activity for over 140 days at room temperature, underscoring its potential for reliable, long-term use in diverse diagnostic applications.

Beyond Correlation: Establishing Causality in Protein Corona Formation for Nanomedicine

In contemporary studies on the role of the protein corona in specific biological applications, identifying correlation is widely used to draw conclusions from observations and statistical methods, yet it merely identifies associations without establishing a direct influence between variables. This over reliance on observation can lead to spurious connections where co-occurrence does not imply causation. In contrast, a causality-focused approach asserts the direct impact of one variable on another, offering a more robust framework for inference and the drawing of scientific conclusions. This approach allows researchers to better predict how changes in a nanoparticle's physicochemical properties or biological conditions will affect protein corona composition and decoration, in turn affecting their safety and therapeutic/diagnostic efficacies. As a proof of concept, we explore the concept of "actual causality" (introduced by Halpern and Pearl) to mathematically prove how spiking small molecules, including metabolites, lipids, vitamins, and nutrients, into plasma can induce diverse protein corona patterns on identical nanoparticles. This approach significantly enhances the depth of plasma proteome profiling. Our findings reveal that among the various spiked small molecules, phosphatidylcholine was the actual cause of the observed increase in the proteomic depth of the plasma sample. By considering the concept of causality in the field of protein coronas, the nanomedicine community can substantially improve the ability to design safer and more efficient nanoparticles for both diagnostic and therapeutic purposes.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2021-2022

The use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates is a well-established technique and this review is the 12th update of the original article published in 1999 and brings coverage of the literature to the end of 2022. As with previous review, this review also includes a few papers that describe methods appropriate to analysis by MALDI, such as sample preparation, even though the ionization method is not MALDI. The review follows the same format as previous reviews. It is divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of computer software for structural identification. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other general areas such as medicine, industrial processes, natural products and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. MALDI is still an ideal technique for carbohydrate analysis, particularly in its ability to produce single ions from each analyte and advancements in the technique and range of applications show little sign of diminishing.

Debugging the dynamics of protein corona: Formation, composition, challenges, and applications at the nano-bio interface

The intricate interplay between nanomaterials and the biological molecules has garnered considerable interest in understanding the dynamics of protein corona formation at the nano-bio interface. This review provides an in-depth exploration of protein-nanoparticle interactions, elucidating their structural dynamics and thermodynamics at the nano-Bio interface and further on emphasizing its formation, composition, challenges, and applications in the biomedical and nanotechnological domains, such as drug delivery, theranostics, and the translational medicine. We delve the nuanced mechanisms governing protein corona formation on nanoparticle surfaces, highlighting the influence of nanoparticle and biological factors, and review the impact of corona formation on the biological identity and functionality of nanoparticles. Notably, emerging applications of artificial intelligence and machine learning have begun to revolutionize this field, enabling accurate prediction of corona composition and related biological outcomes. These tools not only enhance efficiency over traditional experimental methods but also help decode complex protein-nanoparticle interaction patterns, offering new insights into corona-driven cellular responses and disease diagnostics. Additionally, it discusses recent advancements in the field of protein corona, particularly in translational nanomedicine and associated applications entailing current and future strategies which are aimed at mitigating the adverse effects of protein-nanoparticle interactions at the biological interface, for tailoring the protein coronas by engineering of the nanomaterials. This comprehensive assessment from chemical, technological, and biological aspects serves as a guiding beacon for the development of future nanomedicine, enabling the more effective emulation of the biological milieu and the design of protein-NP systems for enhanced biomedical applications.

Boosting Cancer Cell Uptake of Gold Nanoparticles by Light-Modulated Protein Corona Reorganization for Tumor Ablation

Nanoparticles (NPs) administered into the human body are spontaneously modified by forming a protein corona, which is crucial for their biological activity. While NP-based photothermal therapy is an established noninvasive modality for tumor ablation, the impact of light irradiation on protein corona formation and clinical outcomes is unclear. This study unveils the promotive role of light irradiation in cancer cell uptake of gold nanoparticles (GNPs) by modulating the GNP-protein and protein-protein interactions within the corona. Specifically, infrared light irradiation increases the local temperature around GNPs to induce partial unfolding of corona proteins, increasing the availability of binding sites and enhancing adsorption. Additionally, light intensifies competition among different proteins for adsorption, resulting in a 25% increase in the abundance of higher molecular weight proteins, such as human serum albumin (HSA), on the GNP surface after irradiation. Notably, GNPs with positively charged surfaces, compared to GNPs with other modifications, exhibit more significant changes in the protein corona due to stronger electrostatic interactions with proteins (1.32 ± 0.17 × 103 kJ/mol). These variations in the amount, structure, and composition of associated proteins result in a 14.26% increase in GNP uptake by cancer cells, likely due to modifications at the GNP-cell membrane interface. Our findings highlight the critical role of light irradiation in influencing protein corona dynamics and cellular interactions, suggesting its potential as a valuable engineering tool in nanomedicine.

Development of Thermostable and Immunogenic Block Copolymer Nanoparticles (BNPs) for mRNA Delivery

Combining an amphiphilic block copolymer polybutadiene-b-poly(ethylene glycol) (PBD-b-PEO), an ionizable lipid, a helper lipid, and cholesterol produces thermostable BNPs. Luciferase mRNA-BNPs can be stored for over 1 year at 4 °C with no evidence of degradation to the mRNA or nanocarrier. In vivo, mRNA-BNPs exhibit a greater affinity for secondary lymphoid organs than mRNA-lipid nanoparticles (LNPs) and are efficiently taken up by macrophages and dendritic cells. Freshly fabricated ovalbumin (OVA) mRNA-BNPs elicit robust OVA-specific IgG and functional memory CD8+ T cells that persist for at least 5 months. Immunogenicity remains intact after 24 weeks of storage at 4 °C. Anti-PEG antibodies are not boosted by the repeated administration of mRNA-BNPs, unlike mRNA-LNPs. Syrian hamsters vaccinated with SARS-CoV-2 spike mRNA-BNPs are protected against weight loss associated with infection and potently suppress pulmonary viral loads. Protective efficacy is comparable to that conferred by a Comirnaty biosimilar. Cumulatively, mRNA-BNPs are thermostable, immunogenic and possess the potential for clinical application.

Extreme Tolerance of Nanoparticle-Protein Corona to Ultra-High Abundance Proteins Enhances the Depth of Serum Proteomics

The serum nanoparticle-protein corona (NPC) provides specific disease information, thus opening a new avenue for high-throughput in-depth proteomics to facilitate biomarker discovery. Yet, little is known about the interactions between NPs and proteins, and its role in enhanced depth of serum proteomics. Herein, a series of protein spike-in experiments are conducted to systematically investigate protein depletion and enrichment during NPC formation. Proteomic depth is serum concentration-dependent, and NPC exhibits powerful tolerance to ultra-high abundant proteins. In addition, protein-protein interactions (PPI), especially those involving albumin, play a pivotal role in promoting proteomic depth. Furthermore, a triple-protein assay is established to interrogate the relationship between protein binding affinity and concentration. NPC formation is a product of balancing binding affinity, concentration, and PPI. Overall, this study elucidates how NPs achieve protein depletion and enrichment for enhanced serum proteomic depth to gain a better understanding of NPC as an essential tool of proteome profiling.

Harnessing nanoparticles for reshaping tumor immune microenvironment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers, characterized by high morbidity and mortality rates. Recently, immunotherapy has emerged as a crucial treatment modality for HCC, following surgery, locoregional therapies, and targeted therapies. This approach harnesses the body's immune system to target and eliminate cancer cells, potentially resulting in durable antitumor responses. However, acquired resistance and the tumor immunosuppressive microenvironment (TIME) significantly hinder its clinical application. Recently, advancements in nanotechnology, coupled with a deeper understanding of cancer biology and nano-biological interactions, have led to the development of various nanoparticles aimed at enhancing therapeutic efficacy through specific targeting of tumor tissues. These nanoparticles increase the accumulation of immunotherapeutic drugs within the tumor microenvironment, thereby transforming the TIME. In this review, we provide a concise overview of the fundamental principles governing the TIME landscape in HCC and discuss the rationale for and applications of nanoparticles in this context. Additionally, we highlight existing challenges and potential opportunities for the clinical translation of cancer nanomedicines.

Extracellular vesicles of different cellular origin feature distinct biomolecular corona dynamics

Initially observed on synthetic nanoparticles, the existence of biomolecular corona and its role in determining nanoparticle identity and function are now beginning to be acknowledged in biogenic nanoparticles, particularly in extracellular vesicles - membrane-enclosed nanoparticle shuttling proteins, nucleic acids, and metabolites which are released by cells for physiological and pathological communication - we developed a methodology based on fluorescence correlation spectroscopy to track biomolecular corona formation on extracellular vesicles derived from human red blood cells and amniotic membrane mesenchymal stromal cells when these vesicles are dispersed in human plasma. The methodology allows for tracking corona dynamics in situ under physiological conditions. Results evidence that the two extracellular vesicle populations feature distinct corona dynamics. These findings indicate that the dynamics of the biomolecular corona may ultimately be linked to the cellular origin of the extracellular vesicles, revealing an additional level of heterogeneity, and possibly of bionanoscale identity, that characterizes circulating extracellular vesicles.

Omics-Enhanced Nanomedicine for Cancer Therapy

Cancer nanomedicine has emerged as a promising approach to overcome the limitations of conventional cancer therapies, offering enhanced efficacy and safety in cancer management. However, the inherent heterogeneity of tumors presents increasing challenges for the application of cancer nanomedicine in both diagnosis and treatment. This heterogeneity necessitates the integration of advanced and high-throughput analytical techniques to tailor nanomedicine strategies to individual tumor profiles. Omics technologies, encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics, and more, provide unparalleled insights into the molecular and cellular mechanisms underlying cancer. By dissecting tumor heterogeneity across multiple levels, these technologies offer robust support for the development of personalized and precise cancer nanomedicine strategies. In this review, the principles, techniques, and applications of key omics technologies are summarized. Especially, the synergistic integration of omics and nanomedicine in cancer therapy is explored, focusing on enhanced diagnostic accuracy, optimized therapeutic strategies and the assessment of nanomedicine-mediated biological responses. Moreover, this review addresses current challenges and outlines future directions in the field of omics-enhanced nanomedicine. By offering valuable insights and guidance, this review aims to advance the integration of omics with nanomedicine, ultimately driving improved diagnostic and therapeutic strategies for cancer.

Understanding the role of biomolecular coronas in human exposure to nanomaterials

Nanomaterials (NMs) are increasingly used in medical treatments, electronics, and food additives. However, nanosafety-the possible adverse effects of NMs on human health-is an area of active research. This review provides an overview of the influence of biomolecular coronas on NM transformation following various exposure routes. We discuss potential exposure pathways, including inhalation and ingestion, describing the physiology of exposure routes and emphasising the relevance of coronas in these environments. Additionally, we review other routes to NM exposure, such as synovial fluid, blood (translocation and injection), dermal and ocular exposure, as well as the dose and medium impact on NM interactions. We emphasize the need for an in-depth characterisation of coronas in different biological media, highlighting the need and opportunity to study lung and gastric fluids to understand NM behaviour and potential toxicity. Future research aims to predict better in vivo outcomes and address the complexities of NM interactions with biological systems.

Protein Corona of Nanoparticles: Isolation and Analysis

Nanoparticles entering biological systems or fluids inevitably adsorb biomolecules, such as protein, on their surfaces, forming a protein corona. Ensuing, the protein corona endows nanoparticles with a new biological identity and impacts the interaction between the nanoparticles and biological systems. Hence, the development of reliable techniques for protein corona isolation and analysis is key for understanding the biological behaviors of nanoparticles. First, this review systematically outlines the approach for isolating the protein corona, including centrifugation, magnetic separation, size exclusion chromatography, flow-field-flow fractionation, and other emerging methods. Next, we review the qualitative and quantitative characterization methods of the protein corona. Finally, we underscore the necessary steps to advance the efficiency and fidelity of protein corona isolation and characterization on nanoparticle surfaces. We anticipate that these insights into protein corona isolation and characterization methodologies will profoundly influence the development of technologies aimed at elucidating bionano interactions and the role of protein corona in various biomedical applications.

Mass Spectrometry-Based Top-Down Proteomics in Nanomedicine: Proteoform-Specific Measurement of Protein Corona

Conventional mass spectrometry (MS)-based bottom-up proteomics (BUP) analysis of the protein corona [i.e., an evolving layer of biomolecules, mostly proteins, formed on the surface of nanoparticles (NPs) during their interactions with biomolecular fluids] enabled the nanomedicine community to partly identify the biological identity of NPs. Such an approach, however, fails to pinpoint the specific proteoforms─distinct molecular variants of proteins in the protein corona. The proteoform-level information could potentially advance the prediction of the biological fate and pharmacokinetics of nanomedicines. Recognizing this limitation, this study pioneers a robust and reproducible MS-based top-down proteomics (TDP) technique for characterizing proteoforms in the protein corona. Our TDP approach has successfully identified about 900 proteoforms in the protein corona of polystyrene NPs, ranging from 2 to 70 kDa, revealing proteoforms of 48 protein biomarkers with combinations of post-translational modifications, signal peptide cleavages, and/or truncations─details that BUP could not fully discern. This advancement in MS-based TDP offers a more advanced approach to characterize NP protein coronas, deepening our understanding of NPs' biological identities. We, therefore, propose using both TDP and BUP strategies to obtain more comprehensive information about the protein corona, which, in turn, can further enhance the diagnostic and therapeutic efficacy of nanomedicine technologies.

The biomolecular corona of nanomedicines: effects on nanomedicine outcomes and emerging opportunities

Upon administration, nanomedicines adsorb a corona of endogenous biomolecules on their surface, which can affect nanomedicine interactions with cells, targeting, and efficacy. While strategies to reduce protein binding are available, the high selectivity of the adsorbed corona is enabling novel applications, such as for biomarker discovery and rare protein identification. Additionally, the adsorbed molecules can promote interactions with specific cell receptors, thus conferring the nanomedicine new endogenous targeting capabilities. This has been reported for Onpattro, a lipid nanoparticle targeting the hepatocytes via apolipoproteins in its corona. Recently, selective organ-targeting (SORT) nanoparticles have been proposed, which exploit corona-mediated interactions to deliver nanoparticles outside the liver. Strategies for corona seeding and corona engineering are emerging to increase the selectivity of similar endogenous targeting mechanisms.

Biomolecular Corona of Gold Nanoparticles: The Urgent Need for Strong Roots to Grow Strong Branches

Gold nanoparticles (GNPs) are largely employed in diagnostics/biosensors and are among the most investigated nanomaterials in biology/medicine. However, few GNP-based nanoformulations have received FDA approval to date, and promising in vitro studies have failed to translate to in vivo efficacy. One key factor is that biological fluids contain high concentrations of proteins, lipids, sugars, and metabolites, which can adsorb/interact with the GNP's surface, forming a layer called biomolecular corona (BMC). The BMC can mask prepared functionalities and target moieties, creating new surface chemistry and determining GNPs' biological fate. Here, the current knowledge is summarized on GNP-BMCs, analyzing the factors driving these interactions and the biological consequences. A partial fingerprint of GNP-BMC analyzing common patterns of composition in the literature is extrapolated. However, a red flag is also risen concerning the current lack of data availability and regulated form of knowledge on BMC. Nanomedicine is still in its infancy, and relying on recently developed analytical and informatic tools offers an unprecedented opportunity to make a leap forward. However, a restart through robust shared protocols and data sharing is necessary to obtain "stronger roots". This will create a path to exploiting BMC for human benefit, promoting the clinical translation of biomedical nanotools.

Characterization of polyethylene terephthalate (PET) and polyamide (PA) true-to-life nanoplastics and their biological interactions

Plastic and microplastics, including polyethylene (PE), polypropylene (PP), and polystyrene (PS), are major contributors to environmental pollution. However, there is a growing recognition of the need to investigate a wider range of plastic polymers to fully understand the extent and impacts of plastic pollution. This study focuses on the comprehensive characterization of true-to-life nanoplastics (T2LNPs) derived from polyethylene terephthalate (PET) and polyamide (PA) to enhance our understanding of environmental nanoplastics pollution. T2LNPs were produced through cryogenic mechanical fragmentation of everyday items made from these polymers. A solid methodological framework incorporating various characterization techniques was established. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and thermogravimetric analysis (TGA) were employed to study the chemical composition and confirm the absence of chemical modifications possibly occurring during fragmentation. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the morphology of the T2LNPs. Additionally, AFM image analysis compared to dynamic light scattering (DLS) measurements provided insights into the size distribution and the stability of the T2LNP suspensions. The results revealed the heterogeneity of T2LNPs derived from PET and PA, emphasizing the importance of studying different plastic compositions to comprehensively understand nanoplastics pollution. Lastly, the distinctive characteristics and morphology of T2LNPs were translated into the realm of biological interactions, offering initial insights into the influence of these disparities on the formation of the protein corona on the surface of T2LNPs. By proposing T2LNPs as test materials and establishing a comprehensive characterization approach, this study aims to bridge the knowledge gap regarding the behavior and toxicity of nanoplastics. Furthermore, it highlights the need for a reliable and transferable analytical package for nanoplastic characterization to facilitate future studies on the environmental impact of nanoplastics.

Proximity Amplification-Enabled Electrochemical Analysis of Tumor-Associated Glycoprotein Biomarkers

Glycoproteins produced and secreted from specific cells and tissues are associated with several diseases and emerge as typical biomarkers to provide useful information in cancer diagnosis considering their abnormal expression levels. In this work, we design a universal method to achieve the accurate and sensitive analysis of tumor-associated glycoprotein biomarkers based on both carbohydrate recognition and protein recognition at the same protein surface. The byproduct of dual recognition-induced proximity amplification, pyrophosphate, triggers the disassembly of methylene blue-encapsulated metal-organic frameworks, MB@ZIF-90. As a result, methylene blue molecules are released to arouse amplified electrochemical responses for glycoprotein analysis. Experimental results demonstrate the high-accuracy analysis of carcinoembryonic antigen, a typical glycoprotein biomarker in cancer diagnosis, in a linear range of 0.001-100 ng mL-1 with a low limit of detection of 0.419 pg mL-1. The method also displays satisfactory specificity and recoveries in complex serum samples and proves good versatility by adopting two other tumor-associated glycoprotein biomarkers, α-fetoprotein and mucin-1, as the targets. Therefore, this work provides a valuable tool for the analysis of glycoprotein biomarkers, which may be of great potential in early warning of malignant tumors in clinical applications.

In silico prediction of protein binding affinities onto core-shell PEGylated noble metal nanoparticles for rational design of drug nanocarriers

Polymer-coated nanoparticles (NP) are commonly used as drug carriers or theranostic agents. Their uptake rates are modulated by the interactions with essential serum proteins such as transferrin and albumin. Understanding the control parameters of these interactions is crucial for improving the efficiency of these nanoscale devices. In this work, we perform a multiscale computational study of protein adsorption onto polyethylene glycol (PEG) coated gold and silver NPs, producing protein-NP adsorption rankings as a function of PEG grafting density, which are validated against previously reported experimental protein-NP binding constants. Furthermore, the applied nano-docking method provides information on the preferred orientation of proteins immobilised on the surface of NPs. We propose a method of construction of model core-shell NPs in silico. The presented protocol can provide molecular level insights for the experimental development of biosensors, nanocarriers, or other nanoplatforms where information on the preferred orientation of protein at the bio-nano interface is crucial, and enables fast in silico prescreening of assays of various nanocarriers, i.e., combinations of proteins, NPs, and coatings.

Long-term retention of gold nanoparticles in the liver is not affected by their physicochemical characteristics

Gold nanoparticles (GNPs) are considered promising candidates for healthcare applications, however, their toxicity after long-term exposure to the material remains uncertain. Since the liver is the main filter organ for nanomaterials, this work was aimed at evaluating hepatic accumulation, internalisation and overall safety of well-characterised and endotoxin-free GNPs in healthy mice from 15 minutes to 7 weeks after a single administration. Our data demonstrate that GNPs were rapidly segregated into lysosomes of endothelial cells (LSEC) or Kupffer cells regardless of coating or shape but with different kinetics. Despite the long-lasting accumulation in tissues, the safety of GNPs was confirmed by liver enzymatic levels, as they were rapidly eliminated from the blood circulation and accumulated in the liver without inducing hepatic toxicity. Our results demonstrate that GNPs have a safe and biocompatibile profile despite their long-term accumulation.

Programmable DNA Circuit-Facilitated Determination of Circulating Extracellular Vesicle PD-L1 for Lung Cancer Diagnosis and Immunotherapy Response Prediction

Circulating extracellular vesicle (EV) PD-L1 is correlated with the occurrence and progression of lung cancer and has great potential as a valuable diagnostic and immunotherapy predictive biomarker. In this work, we propose a fluorescent biosensing method for the sensitive and accurate determination of circulating EV PD-L1. Specifically, after the phosphatidylserine-targeting peptide-assisted magnetic enrichment, a programmable DNA circuit is designed to translate the presence of PD-L1 to the appearance of numerous duplex DNA probes on the circulating EV surface. Upon fructose treatment, these newly formed duplex DNA probes are released from the EV surface to activate the trans-cleavage activity of CRISPR/Cas12a system, which finally produces a significant fluorescence signal. Experimental results reveal that the method not only enables sensitive determination of EV PD-L1 with a detection limit of 67 particles/mL but also demonstrates the potential use in the diagnosis and immunotherapy response prediction of lung cancer in a principle-of-proof study. Therefore, the method may provide a useful tool for EV PD-L1 determination, which may provide valuable information for the precise diagnosis and personalized treatment of lung cancer patients.

The protein corona from nanomedicine to environmental science

The protein corona spontaneously develops and evolves on the surface of nanoscale materials when they are exposed to biological environments, altering their physiochemical properties and affecting their subsequent interactions with biosystems. In this Review, we provide an overview of the current state of protein corona research in nanomedicine. We next discuss remaining challenges in the research methodology and characterization of the protein corona that slow the development of nanoparticle therapeutics and diagnostics, and we address how artificial intelligence can advance protein corona research as a complement to experimental research efforts. We then review emerging opportunities provided by the protein corona to address major issues in healthcare and environmental sciences. This Review details how mechanistic insights into nanoparticle protein corona formation can broadly address unmet clinical and environmental needs, as well as enhance the safety and efficacy of nanobiotechnology products.

Basic and advanced spectrometric methods for complete nanoparticles characterization in bio/eco systems: current status and future prospects

The use of engineered nanoparticles in the environment and human life has increased in the last 20 years. The risk assessment concerning application of nanomaterials in biological systems requires their thorough characterization. Understanding the correlations between physicochemical properties of nanoparticles concerning not only the size, particle size distribution, number concentration, degree of aggregation, or agglomeration but also solubility, stability, binding affinity, surface activity, chemical composition, and nanoparticle synthesis yield allows their reliable characterization. Thus, to find the structure-function/property relationship of nanoparticles, multifaceted characterization approach based on more than one analytical technique is required. On the other hand, the increasing demand for identification and characterization of nanomaterials has contributed to the continuous development of spectrometric techniques which enables for their qualitative and quantitative analysis in complex matrices giving reproducible and reliable results. This review is aimed at providing a discussion concerning four main aspects of nanoparticle characterization: nanoparticle synthesis yield, particle size and number concentration, elemental and isotopic composition of nanoparticles, and their surface properties. The conventional and non-conventional spectrometric techniques such as spectrophotometry UV-Vis, mass spectrometric techniques working in conventional and single-particle mode, or those based on optical emission detection systems are described with special emphasis paid on their advantages and drawbacks. The application and recent advances of these methods are also comprehensively reviewed and critically discussed.

Nanoparticle protein corona: from structure and function to therapeutic targeting

Nanoparticle (NP)-based therapeutics have ushered in a new era in translational medicine. However, despite the clinical success of NP technology, it is not well-understood how NPs fundamentally change in biological environments. When introduced into physiological fluids, NPs are coated by proteins, forming a protein corona (PC). The PC has the potential to endow NPs with a new identity and alter their bioactivity, stability, and destination. Additionally, the conformation of proteins is sensitive to their physical and chemical surroundings. Therefore, biological factors and protein-NP-interactions can induce changes in the conformation and orientation of proteins in vivo. Since the function of a protein is closely connected to its folded structure, slight differences in the surrounding environment as well as the surface characteristics of the NP materials may cause proteins to lose or gain a function. As a result, this can alter the downstream functionality of the NPs. This review introduces the main biological factors affecting the conformation of proteins associated with the PC. Then, four types of NPs with extensive utility in biomedical applications are described in greater detail, focusing on the conformation and orientation of adsorbed proteins. This is followed by a discussion on the instances in which the conformation of adsorbed proteins can be leveraged for therapeutic purposes, such as controlling protein conformation in assembled matrices in tissue, as well as controlling the PC conformation for modulating immune responses. The review concludes with a perspective on the remaining challenges and unexplored areas at the interface of PC and NP research.

Silver nanoparticle interactions with glycated and non-glycated human serum albumin mediate toxicity

Introduction: Biomolecules bind to and transform nanoparticles, mediating their fate in biological systems. Despite over a decade of research into the protein corona, the role of protein modifications in mediating their interaction with nanomaterials remains poorly understood. In this study, we evaluated how glycation of the most abundant blood protein, human serum albumin (HSA), influences the formation of the protein corona on 40 nm silver nanoparticles (AgNPs) and the toxicity of AgNPs to the HepG2 human liver cell line. Methods: The effects of glycation on AgNP-HSA interactions were quantified using circular dichroism spectroscopy to monitor protein structural changes, dynamic light scattering to assess AgNP colloidal stability, zeta potential measurements to measure AgNP surface charge, and UV-vis spectroscopy and capillary electrophoresis (CE) to evaluate protein binding affinity and kinetics. The effect of the protein corona and HSA glycation on the toxicity of AgNPs to HepG2 cells was measured using the WST cell viability assay and AgNP dissolution was measured using linear sweep stripping voltammetry. Results and Discussion: Results from UV-vis and CE analyses suggest that glycation of HSA had little impact on the formation of the AgNP protein corona with protein-AgNP association constants of ≈2x107 M-1 for both HSA and glycated HSA (gHSA). The formation of the protein corona itself (regardless of whether it was formed from HSA or glycated HSA) caused an approximate 2-fold decrease in cell viability compared to the no protein AgNP control. While the toxicity of AgNPs to cells is often attributed to dissolved Ag(I), dissolution studies showed that the protein coated AgNPs underwent less dissolution than the no protein control, suggesting that the protein corona facilitated a nanoparticle-specific mechanism of toxicity. Overall, this study highlights the importance of protein coronas in mediating AgNP interactions with HepG2 cells and the need for future work to discern how protein coronas and protein modifications (like glycation) may alter AgNP reactivity to cellular organisms.

Biomolecular Corona Stability in Association with Plasma Cholesterol Level

Biomolecular corona is spontaneously formed on the surface of nanoparticles (NPs) when they are in contact with biological fluids. It plays an important role in the colloidal stability of NPs, which is of importance for most of their medical applications and toxicity assessment. While typical studies use either blood plasma or serum from a pooled biobank, it is unclear whether differences in the media, such as cholesterol level or protein concentration, might affect the NP colloidal stability and corona composition. In this study, the silica corona was prepared at particularly low plasma concentrations (3%, v/v–1.98 mg/mL) to identify the critical roles of the protein mass/NP surface ratio and the level of plasma cholesterol on the corona protein pattern and particle stability. While depending on the plasma dilution factor, the corona protein composition could be controlled by keeping the protein/NP constant. The NP colloidal stability was found to strongly correlate with the level of cholesterol in human plasma, particularly due to the high enrichment of high-density lipoprotein (HDL) and low-density lipoprotein (LDL) in the corona. A cohort study on plasma samples from individuals with known cholesterol levels was performed to highlight that association, which could be relevant for all corona systems enriched with the LDL.