Identifying new therapeutic targets via modulation of protein corona formation by engineered nanoparticles

Exposure to 7,12-dimethylbenz[a]anthracene impacts ovarian DNA damage sensing and repair proteins differently in lean and obese female mice and weight loss may mitigate obesity-induced ovarian dysfunction

Obesity impairs oocyte quality, fertility, pregnancy maintenance, and is associated with offspring birth defects. The model ovotoxicant, 7,12-dimethylbenz[a]anthracene (DMBA), causes ovarian DNA damage and follicle loss. Both DMBA-induced chemical biotransformation and the DNA damage response are partially attenuated in obese relative to lean female mice but whether weight loss could improve the DNA damage response to DMBA exposure has not been explored. Thus, at six weeks of age, C57BL/6 J female mice were divided in three groups: 1) Lean (L; n = 20) fed a chow diet for 12 weeks, 2) obese (O; n = 20) fed a high fat high sugar (HFHS) diet for 12 weeks and, 3) slim-down (S; n = 20). The S group was fed with HFHS diet for 7 weeks until attaining a higher body relative to L mice on week 7.5 and switched to a chow diet for 5 weeks to achieve weight loss. Mice then received either corn oil (CT) or DMBA (D; 1 mg/kg) for 7 d via intraperitoneal injection (n = 10/treatment). Obesity increased (P < 0.05) kidney and spleen weight, and DMBA decreased uterine weight (P < 0.05). Ovarian weight was reduced (P < 0.05) in S mice, but DMBA exposure increased ovary weight in the S mice. LC-MS/MS identified 18, 64, and 7 ovarian proteins as altered (P < 0.05) by DMBA in the L, S and O groups, respectively. In S and O mice, 24 and 8 proteins differed, respectively, from L mice. These findings support weight loss as a strategy to modulate the ovarian genotoxicant response.

Gold Nanoparticles Inhibit Macropinocytosis by Decreasing KRAS Activation

The RAS-transformed cells utilize macropinocytosis to acquire amino acids to support their uncontrolled growth. However, targeting RAS to inhibit macropinocytosis remains a challenge. Here, we report that gold nanoparticles (GNP) inhibit macropinocytosis by decreasing KRAS activation. Using surface-modified and unmodified GNP, we showed that unmodified GNP specifically sequestered both wild-type and mutant KRAS and inhibited its activation, irrespective of growth factor stimulation, while surface-passivated GNP had no effect. Alteration of KRAS activation is reflected on downstream signaling cascades, macropinocytosis and tumor cell growth in vitro, and two independent preclinical human xenograft models of pancreatic cancer in vivo. The current study demonstrates NP-mediated inhibition of macropinocytosis and KRAS activation and provides translational opportunities to inhibit tumor growth in a number of cancers where activation of KRAS plays a major role.

Carbonaceous Nanomaterials for Phototherapy of Cancer

Carbonaceous nanomaterials (CNMs) have drawn tremendous biomedical research interest because of their unique structural features. Recently, CNMs, namely carbon dots, fullerenes, graphene, etc, have been successful in establishing them as considerable nanotherapeutics for phototherapy applications due to their electrical, thermal, and surface properties. This review aims to crosstalk the current understanding of CNMs as multimodal compounds in photothermal and photodynamic therapies as an integrated approach to treating cancer. It also expounds on phototherapy's biomechanics and illustrates its relation to cancer biomodulation. Critical considerations related to the structural properties, fabrication approaches, surface functionalization strategies, and biosafety profiles of CNMs have been explained. This article provides an overview of the most recent developments in the study of CNMs used in phototherapy, emphasizing their usage as nanocarriers. To conquer the current challenges of CNMs, we can raise the standard of cancer therapy for patients. The review will be of interest to the researchers working in the area of photothermal and photodynamic therapies and aiming to explore CNMs and their conjugates in cancer therapy.

Nanotechnology Meets Oncology: A Perspective on the Role of the Personalized Nanoparticle-Protein Corona in the Development of Technologies for Pancreatic Cancer Detection

In recent years nanotechnology has opened exciting opportunities in the struggle against cancer. In 2007 Dawson and coworkers demonstrated that nanomaterials exposed to biological fluids are coated with plasma proteins that form the so-called “protein corona”. A few years later our joint research team made of physicists, chemists, biotechnologists, surgeons, oncologists, and bioinformaticians introduced the concept of “personalized protein corona” and demonstrated that it is unique for each human condition. This concept paved the way for the development of nano-enabled blood (NEB) tests for the diagnosis of pancreatic ductal adenocarcinoma (PDAC). These studies gave an impetus to serious work in the field that came to maturity in the late 2010s. In this special issue, we provide the reader with a comprehensive overview of the most significant discoveries of our research team in the field of PDAC detection. We focus on the main achievements with an emphasis on the fundamental aspects of this arena and how they shaped the integration of different scientific backgrounds towards the development of advanced diagnostic technologies. We conclude the review by outlining future perspectives and opportunities to transform the NEB tests into a reliable clinical diagnostic technology for early diagnosis, follow-up, and management of PDAC patients.

Camels' biological fluids contained nanobodies: promising avenue in cancer therapy

Cancer is a major health concern and accounts for one of the main causes of death worldwide. Innovative strategies are needed to aid in the diagnosis and treatment of different types of cancers. Recently, there has been an evolving interest in utilizing nanobodies of camel origin as therapeutic tools against cancer. Nanotechnology uses nanobodies an emerging attractive field that provides promises to researchers in advancing different scientific sectors including medicine and oncology. Nanobodies are characteristically small-sized biologics featured with the ability for deep tissue penetration and dissemination and harbour high stability at high pH and temperatures. The current review highlights the potential use of nanobodies that are naturally secreted in camels’ biological fluids, both milk and urine, in the development of nanotechnology-based therapy for treating different typesQuery of cancers and other diseases. Moreover, the role of nano proteomics in the invention of novel therapeutic agents specifically used for cancer intervention is also illustrated.

Gold Nanoparticles Contact with Cancer Cell: A Brief Update

The fine-tuning of the physicochemical properties of gold nanoparticles has facilitated the rapid development of multifunctional gold-based nanomaterials with diagnostic, therapeutic, and therapeutic applications. Work on gold nanoparticles is increasingly focusing on their cancer application. This review provides a summary of the main biological effects exerted by gold nanoparticles on cancer cells and highlights some critical factors involved in the interaction process (protein corona, tumor microenvironment, surface functionalization). The review also contains a brief discussion of the application of gold nanoparticles in target discovery.

Nanoparticle-protein corona complex: understanding multiple interactions between environmental factors, corona formation, and biological activity

The surfaces of pristine nanoparticles become rapidly coated by proteins in biological fluids, forming the so-called protein corona. The corona modifies key physicochemical characteristics of nanoparticle surfaces that modulate its biological and pharmacokinetic activity, biodistribution, and safety. In the two decades since the protein corona was identified, the importance of nanoparticles surface properties in regulating biological responses have been recognized. However, there is still a lack of clarity about the relationships between physiological conditions and corona composition over time, and how this controls biological activities/interactions. Here we review recent progress in characterizing the structure and composition of protein corona as a function of biological fluid and time. We summarize the influence of nanoparticle characteristics on protein corona composition and discuss the relevance of protein corona to the biological activity and fate of nanoparticles. The aim is to provide a critical summary of the key factors that affect protein corona formation (e.g. characteristics of nanoparticles and biological environment) and how the corona modulates biological activity, cellular uptake, biodistribution, and drug delivery. In addition to a discussion on the importance of the characterization of protein corona adsorbed on nanoparticle surfaces under conditions that mimic relevant physiological environment, we discuss the unresolved technical issues related to the characterization of nanoparticle-protein corona complexes during their journey in the body. Lastly, the paper offers a perspective on how the existing nanomaterial toxicity data obtained from in vitro studies should be reconsidered in the light of the presence of a protein corona, and how recent advances in fields, such as proteomics and machine learning can be integrated into the quantitative analysis of protein corona components.

Quantitative Analysis of Protein Corona on Precoated Protein Nanoparticles and Determined Nanoparticles with Ultralow Protein Corona and Efficient Targeting in Vivo

The protein corona on nanoparticles (NPs) is a critical problem that often screens the targeting molecules and becomes one of the key reasons for the lack of practical application in nanotherapy. It is critical to fully understand the mechanism of the nanoparticle-biological interactions to design the nanoparticle-based therapeutic agents. Some types of proteins can be precoated on the nanoparticles to avoid unwanted protein attachment; however, the ultralow level of protein corona is hard to achieve, and the relationship of the antifouling property of the precoated protein nanoparticles with protein conformation and protein-nanoparticle interaction energy has never been investigated. In this work, we provided the quantitative protein corona composition analysis on different precoated protein nanoparticles, and on the basis of the molecular simulation process, we found their antifouling property strongly depended on the interaction energy of the precoated protein-serum protein pair and the number of hydrogen bonds formed between them. Furthermore, it also depended on the nanoparticle-serum protein pair interaction energy and the protein conformation on the nanoparticle. The casein coated nanoparticle with the antifouling property was determined, and after aptamer conjugation and drug loading, they exhibited superior targeting and internalization behavior for photodynamic and photothermal therapy in vitro and in vivo. Our work adds to the understanding of the protein corona behavior of precoated protein nanoparticles, and the determined antifouling NP can potentially be used as a highly efficient nanodrug carrier.

How to effectively prepare a sample for bottom-up proteomic analysis of nanoparticle protein corona? A critical review

Since the interest in the biomedical applications of inorganic nanoparticles (NPs) has rapidly grown over the last decades, there is a need for a thorough characterization of bio-nano interactions. NPs introduced to the body (mostly intravenously) encounter plasma proteins, that instantly create a so-called "protein corona" on the NPs surface, giving the nanomaterial a new biological identity. Type of the proteins that interact with NPs may affect the in vivo fate of NPs. For that reason, it is particularly important to establish analytical methods capable of corona protein identification. Bottom-up proteomics is most often used for that purpose. A crucial part of the experiment is sample preparation, as it is already proven that different protocols may lead to distinct results. This review is aimed at providing a characterization of two main stages of sample preparation: separation of NPs with protein corona from the unbound proteins and the digestion of corona proteins. Separation techniques such as centrifugation, magnetic separation, and chromatography and three digestion methods (in-gel, in-solution, and on-particle) are described with special emphasis paid on their advantages and disadvantages as well as their influence on the result of identification. This paper also indicates the need for standardization of protein corona identification protocols, as some of the proteins may be preferentially detected while applying a particular digestion procedure.

Efficient pancreatic cancer detection through personalized protein corona of gold nanoparticles

Characterization of the personalized protein corona (PC) that forms around nanomaterials upon exposure to human plasma is emerging as powerful technology for early cancer detection. However, low material stability and interbatch variability have limited its clinical application so far. Here, we present a nanoparticle-enabled blood (NEB) test that uses 120 nm gold nanoparticles (NPs) as the accumulator of blood plasma proteins. In the test, the personalized PC of gold NPs is characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis. As a paradigmatic case study, pancreatic ductal adenocarcinoma (PDAC) was chosen due to the lack of effective detection strategies that lead to poor survival rate after diagnosis (<1 year) and extremely low 5-years survival rate (15-20%). Densitometric analysis of 75 protein patterns (28 from healthy subjects and 47 from PDAC patients) allowed us to distinguish nononcological and PDAC patients with good sensitivity (78.6%) and specificity (85.3%). The gold NEB test is completely aligned to affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverable to end users criteria stated by the World Health Organization for cancer screening and detection. Thus, it could be very useful in clinical practice at the first level of investigation to decide whether to carry out more invasive analyses or not.

Experimental conditions influence the formation and composition of the corona around gold nanoparticles

BACKGROUND

Ovarian cancer is one of the deadliest gynecological malignancies. While the overall survival of ovarian cancer patients has slightly improved in recent years in the developed world, it remains clinically challenging due to its frequent late diagnosis and the lack of reliable diagnostic and/or prognostic markers. The aim of this study was to identify potential new molecular target proteins (NMTPs) responsible for the poor outcomes. When nanoparticles (NP) are exposed to biological fluids, a protein coat, termed the protein corona (PC), forms around the NP, and the PC represents a tool to identify NMTPs. This study investigates the influence of pre-processing conditions, such as lysis conditions and serum/plasma treatment, on the PC composition and the resulting identification of NMTPs.

RESULTS

Using gel electrophoresis, pre-processing conditions, including cell-lysis techniques and enrichment of low-abundance proteins (LAPs) by immunocentrifugation of serum/plasma, were shown to alter the relative amounts and compositions of proteins. PCs formed when 20 nm gold-NPs (GNPs) were incubated with lysate proteins from either RIPA- or urea lysis. Proteomic analysis of these PCs showed 2-22-fold enrichment of NMTPs in PCs from urea lysates as compared to RIPA lysates. Enriched NMTPs were then classified as cellular components, biological and molecular functions-associated proteins. The impact of enriched LAPs (eLAPs) on both PC composition and NMTP identification was shown by comparative proteomic analysis of original plasma, eLAPs, and PCs derived from eLAPs; eLAPs-PCs enhanced the abundance of NMTPs approximately 13%. Several NMTPs, including gasdermin-B, dermcidin, and kallistatin, were identified by this method demonstrating the potential use of this PC approach for molecular target discovery.

CONCLUSION

The current study showed that the pre-processing conditions modulate PC composition and can be used to enhance identification of NMTPs.

A Novel Nanoproteomic Approach for the Identification of Molecular Targets Associated with Thyroid Tumors

A thyroid nodule is the most common presentation of thyroid cancer; thus, it is extremely important to differentiate benign from malignant nodules. Within malignant lesions, classification of a thyroid tumor is the primary step in the assessment of the prognosis and selection of treatment. Currently, fine-needle aspiration biopsy (FNAB) is the preoperative test most commonly used for the initial thyroid nodule diagnosis. However, due to some limitations of FNAB, different high-throughput “omics” approaches have emerged that could further support diagnosis based on histopathological patterns. In the present work, formalin-fixed paraffin-embedded (FFPE) tissue specimens from normal (non-neoplastic) thyroid (normal controls (NCs)), benign tumors (follicular thyroid adenomas (FTAs)), and some common types of well-differentiated thyroid carcinoma (follicular thyroid carcinomas (FTCs), conventional or classical papillary thyroid carcinomas (CV-PTCs), and the follicular variant of papillary thyroid carcinomas (FV-PTCs)) were analyzed. For the first time, FFPE thyroid samples were deparaffinized using an easy, fast, and non-toxic method. Protein extracts from thyroid tissue samples were analyzed using a nanoparticle-assisted proteomics approach combined with shotgun LC-MS/MS. The differentially regulated proteins found to be specific for the FTA, FTC, CV-PTC, and FV-PTC subtypes were analyzed with the bioinformatic tools STRING and PANTHER showing a profile of proteins implicated in the thyroid cancer metabolic reprogramming, cancer progression, and metastasis. These proteins represent a new source of potential molecular targets related to thyroid tumors.

Denatured corona proteins mediate the intracellular bioactivities of nanoparticles via the unfolded protein response

Biomolecular corona formed on nanoparticles (NPs) influences the latter's in vivo biological effects. Nanomaterials with different physicochemical properties exert similar adverse effects, such as cytotoxicity, suggesting the existence of ubiquitous signals during various corona formations that mediate common and fundamental cellular events. Here, we discover the involvement of the unfolded protein response (UPR) and recruited chaperones in the corona. Specially, heat shock protein 90 kDa α class B member 1 (Hsp90ab1) is abundantly enriched in the corona, accompanied by substantial aggregation of misfolded protein on particles intracellularly. Further analysis reveals the particulate matter 2.5 (PM2.5) and metal-containing particles are more capable of denaturing proteins. The recruited Hsp90ab1 activates diverse NPs' pathological behaviour by heat stress response (HSR), which were significantly reversed by geldanamycin (GA), the inhibitor of Hsp90ab1. Murine lung inflammation induced by PM2.5 and iron oxide NPs (Fe₃O₄NPs) is suppressed by GA, highlighting that Hsp90ab1-mediated UPR is a potential target for the treatment of environmental pollution-related illnesses. Based on our findings, the UPR and Hsp90ab1 presented in the corona of particles initiate fundamental intracellular reactions that lead to common pathological outcomes, which may provide new insights for understanding nanotoxicity and designing therapeutic approaches for diseases associated with environmental pollution.

Intranasal administration of gold nanoparticles designed to target the central nervous system: Fabrication and comparison between nanospheres and nanoprisms

The presence of the blood-brain barrier (BBB) limit gold nanoparticles (GNP) accumulation in central nervous system (CNS) after intravenous (IV) administration. The intranasal (IN) route has been suggested as a good strategy for circumventing the BBB. In this report, we used gold nanoprisms (78 nm) and nanospheres (47 nm), of comparable surface areas (8000 vs 7235 nm²) functionalized with a polyethylene glycol (PEG) and D1 peptide (GNPr-D1 and GNS-D1, respectively) to evaluate their delivery to the CNS after IN administration. Cell viability assay showed that GNPr-D1 and GNS-D1 were not cytotoxic at concentrations ranged between 0.05 and 0.5 nM. IN administration of GNPr-D1 and GNS-D1 demonstrated a significant difference between the two types of GNP, in which the latter reached the CNS in higher levels. Pharmacokinetic study showed that the peak brain level of gold was 0.75 h after IN administration of GNS-D1. After IN and IV administrations of GNS-D1, gold concentrations found in brain were 55 times higher via the IN route compared to IV administration. Data revealed that the IN route is more effective for targeting gold to the brain than IV administration. Finally, no significant difference was observed between the IN and IV routes in the distribution of GNS-D1 in the various brain areas.

Protein corona: Dr. Jekyll and Mr. Hyde of nanomedicine

Nanomedicine is an interdisciplinary field of research, comprising science, engineering, and medicine. Many are the clinical applications of nanomedicine, such as molecular imaging, medical diagnostics, targeted therapy, and image-guided surgery. Despite major advances during the past 20 years, many efforts must be done to understand the complex behavior of nanoparticles (NPs) under physiological conditions, the kinetic and thermodynamic principles, involved in the rational design of NP. Once administrated in physiological environment, NPs interact with biomolecules and they are surrounded by protein corona (PC) or biocorona. PC can trigger an immune response, affecting NPs toxicity and targeting capacity. This review aims to provide a detailed description of biocorona and of parameters that are able to control PC formation and composition. Indeed, the review provides an overview about the role of PC in the modulation of both cytotoxicity and immune response as well as in the control of targeting capacity.

Ubiquitin-binding associated protein 2 regulates KRAS activation and macropinocytosis in pancreatic cancer

Macropinocytosis supports the metabolic requirement of RAS-transformed pancreatic ductal adenocarcinoma cells (PDACs). However, regulators of RAS-transformation (activation) that lead to macropinocytosis have not been identified. Herein, we report that UBAP2 (ubiquitin-binding associated protein 2), regulates the activation of KRAS and macropinocytosis in pancreatic cancer. We demonstrate that UBAP2 is highly expressed in both pancreatic cancer cell lines and tumor tissues of PDAC patients. The expression of UBAP2 is associated with poor overall survival in several cancers, including PDAC. Silencing UBAP2 decreases the levels of activated KRAS, and inhibits macropinocytosis, and tumor growth in vivo. Using a UBAP2-deletion construct, we demonstrate that the UBA-domain of UBAP2 is critical for the regulation of macropinocytosis and maintaining the levels of activated KRAS. In addition, UBAP2 regulates RAS downstream signaling and helps maintain RAS in the GTP-bound form. However, the exact mechanism by which UBAP2 regulates KRAS activation is unknown and needs further investigation. Thus, UBAP2 may be exploited as a potential therapeutic target to inhibit macropinocytosis and tumor growth in activated KRAS-driven cancers.

A method to measure the denatured proteins in the corona of nanoparticles based on the specific adsorption of Hsp90ab1

The protein corona influences and determines the biological function of nanoparticles (NPs) in vivo. Analysis and understanding of the activities of proteins in coronas are crucial for nanobiology and nanomedicine research. Misfolded proteins in the corona of NPs theoretically exist, and a protein denaturation-related cellular response might occur in this process as well as in related diseases. The exact evaluation of protein denaturation in the corona is valuable to assess the bioactivities of NPs. Here, we found that the level of adsorbed heat shock protein 90 kDa α class B member 1 (Hsp90ab1) by the denatured protein in iron-cobalt-nickel alloy NPs (FeCoNi NPs) and iron oxide NPs (Fe₃O₄ NPs) was correlated with circular dichroism (CD) analysis and 1-anilinonaphthalene-8-sulfonate (ANS) analysis. The content of Hsp90ab1 in the corona could be easily analysed by western blotting (WB). Further analysis suggested that the method could precisely show the time-dependent protein denaturation on Fe₃O₄ NPs, as well as the influence of the size and the surface modification. More importantly, this method could be applied to other proteins, like lysozyme, other than albumin. Based on the results and the correlation analysis, incubation and detection of Hsp90ab1 in the NP-corona complex can be used as a new and feasible method to evaluate protein denaturation induced by NPs.

Insights into Characterization Methods and Biomedical Applications of Nanoparticle-Protein Corona

Nanoparticles (NPs) exposed to a biological milieu will strongly interact with proteins, forming "coronas" on the surfaces of the NPs. The protein coronas (PCs) affect the properties of the NPs and provide a new biological identity to the particles in the biological environment. The characterization of NP-PC complexes has attracted enormous research attention, owing to the crucial effects of the properties of an NP-PC on its interactions with living systems, as well as the diverse applications of NP-PC complexes. The analysis of NP-PC complexes without a well-considered approach will inevitably lead to misunderstandings and inappropriate applications of NPs. This review introduces methods for the characterization of NP-PC complexes and investigates their recent applications in biomedicine. Furthermore, the review evaluates these characterization methods based on comprehensive critical views and provides future perspectives regarding the applications of NP-PC complexes.

Analysing the nanoparticle-protein corona for potential molecular target identification

When nanoparticles are introduced into biological systems, host proteins tend to associate on the particle surface to form a protein layer termed the "protein corona" (PC). Identifying the proteins that constitute the PC can yield useful information about nanoparticle processing, bio-distribution, toxicity and clearance. Similarly, characterizing and identifying proteins within the PC from patient samples provides opportunities to probe disease proteomes and identify molecules that influence the disease process. Thus, nanoparticles represent unique probing tools for discovery of molecular targets for diseases. Here, we report a first review on target identification using nanoparticles in biological samples based on analysing physico chemical interactions. We also summarize the evolution of the PC surrounding various nano-systems, comment on PC signature, address PC complexity in fluids, and outline challenges associated with analysing the PC. In addition, the influence on PC formation of various nanoparticle parameters is summarized; nanoparticle characteristics considered include size, charge, temperature, and surface modifications for both organic and inorganic nanomaterials. We also discuss the advantages of nanotechnology, over other more invasive and laborious methods, for identifying potential diagnostic and therapeutic targets.

Isolation methods for particle protein corona complexes from protein-rich matrices

Background: Nanoparticles become rapidly encased by a protein layer when they are in contact with biological fluids. This protein shell is called a corona. The composition of the corona has a strong influence on the surface properties of the nanoparticles. It can affect their cellular interactions, uptake and signaling properties. For this reason, protein coronae are investigated frequently as an important part of particle characterization. Main body of the abstract: The protein corona can be analyzed by different methods, which have their individual advantages and challenges. The separation techniques to isolate corona-bound particles from the surrounding matrices include centrifugation, magnetism and chromatographic methods. Different organic matrices, such as blood, blood serum, plasma or different complex protein mixtures, are used and the approaches vary in parameters such as time, concentration and temperature. Depending on the investigated particle type, the choice of separation method can be crucial for the subsequent results. In addition, it is important to include suitable controls to avoid misinterpretation and false-positive or false-negative results, thus allowing the achievement of a valuable protein corona analysis result. Conclusion: Protein corona studies are an important part of particle characterization in biological matrices. This review gives a comparative overview about separation techniques, experimental parameters and challenges which occur during the investigation of the protein coronae of different particle types.

Mass spectrometric approach for the analysis of the hard protein corona of nanoparticles in living cells

The diagnostic and therapeutic application of nanoparticles requires comprehensive knowledge of their interaction with the biomolecular surroundings. The formation of the protein corona on nanoparticles that were internalized by living cells is yet to be understood. In this study, we present a robust approach for the electrophoretic and mass spectrometric analysis of the hard protein corona composition formed in living cells on ~30 nm citrate-stabilized gold nanoparticles, i.e., the proteins with the highest affinity towards the gold nanoparticle surface. The gold nanoparticles were internalized by MCF-7 cells for 24 h followed by the extraction of the hard protein corona‑gold nanoparticle bioconjugates from living cell cultures. The extracted proteins were then separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed by ESI-Q-TOF-MS, which allowed to identify 108 hard corona proteins. The experiments were repeated with J774 macrophage cells with incubation times of 1.5 h, 3 h, 6 h, and 24 h, and the results showed that the hard protein corona remained unchanged over time. Therefore, the proposed experimental approach proved to be a valuable tool for identifying hard corona proteins of nanoparticles internalized by living cells.

Potential clinical applications of the personalized, disease-specific protein corona on nanoparticles

Nanoscale objects lose their original identity once in contact with biological fluids and get a new biological identity, referred to as a protein corona (PC). The PC modifies many of the physicochemical properties of nanoparticles (NPs), including surface charge, size, and aggregation state. These changes, in turn, affect the biological fate of NPs, including their biodistribution, pharmacokinetics, and therapeutic efficacy. It is well known that even small differences in the composition of a protein source (e.g., plasma and serum) can considerably change the composition of the corona formed on the surface of the same NPs. Recently, it has been shown that the PC is intensely affected by the patient's specific disease. Consequently, the same nanomaterial incubated with proteins of biological fluids belonging to patients with different pathologies adsorbs protein coronas with different compositions, giving rise to the concept of the personalized protein corona (PPC). Herein, we review recent advances on the topic of PPC, with a particular focus on their clinical significance.

Nanoparticle Interactions with the Tumor Microenvironment

Compared to normal tissues, the tumor microenvironment (TME) has a number of aberrant characteristics including hypoxia, acidosis, and vascular abnormalities. Many researchers have sought to exploit these anomalous features of the TME to develop anticancer therapies, and several nanoparticle-based cancer therapeutics have resulted. In this Review, we discuss the composition and pathophysiology of the TME, introduce nanoparticles (NPs) used in cancer therapy, and address the interaction between the TME and NPs. Finally, we outline both the potential problems that affect TME-based nanotherapy and potential strategies to overcome these challenges.

Synthetic and biological identities of polymeric nanoparticles influencing the cellular delivery: An immunological link

Enhanced understanding of bio-nano interaction requires recognition of hidden factors such as protein corona, a layer of adsorbed protein around nano-systems. This study compares the biological identity and fingerprint profile of adsorbed proteins on PLGA-based nanoparticles through nano-liquid chromatography-tandem mass spectrometry. The total proteins identified in the corona of nanoparticles (NPs) with different in size, charge and compositions were classified based on molecular mass, isoelectric point and protein function. A higher abundance of complement proteins was observed in modified NPs with an increased size, while NPs with a positive surface charge exhibited the minimum adsorption for immunoglobulin proteins. A correlation of dysopsonin/opsonin ratio was found with cellular uptake of NPs exposed to two positive and negative Fc receptor cell lines. Although the higher abundance of dysopsonins such as apolipoproteins may cover the active sites of opsonins causing a lower uptake, the correlation of adsorbed dysopsonin/opsonin proteins on the NPs surface has an opposite trend with the intensity of cell uptake. Despite the reduced uptake of corona-coated NPs in comparison with pristine NPs, the dysopsonin/opsonin ratio controlled by the physicochemistry properties of NPs could potentially be used to tune up the cellular delivery of polymeric NPs.

A health concern regarding the protein corona, aggregation and disaggregation

Nanoparticle (NP)-protein complexes exhibit the "correct identity" of NP in biological media. Therefore, protein-NP interactions should be closely explored to understand and modulate the nature of NPs in medical implementations. This review focuses mainly on the physicochemical parameters such as dimension, surface chemistry, morphology of NPs, and influence of pH on the formation of protein corona and conformational changes of adsorbed proteins by different kinds of techniques. Also, the impact of protein corona on the colloidal stability of NPs is discussed. Uncontrolled protein attachment on NPs may bring unwanted impacts such as protein denaturation and aggregation. In contrast, controlled protein adsorption by optimal concentration, size, pH, and surface modification of NPs may result in potential implementation of NPs as therapeutic agents especially for disaggregation of amyloid fibrils. Also, the effect of NPs-protein corona on reducing the cytotoxicity and clinical implications such as drug delivery, cancer therapy, imaging and diagnosis will be discussed. Validated correlative physicochemical parameters for NP-protein corona formation frequently derived from protein corona fingerprints of NPs which are more valid than the parameters obtained only on the base of NP features. This review may provide useful information regarding the potency as well as the adverse effects of NPs to predict their behavior in vivo.

Mannose-decorated hybrid nanoparticles for enhanced macrophage targeting

Our goal was to design nanocarriers that specifically target and deliver therapeutics to polarized macrophages. Mannose receptors are highly overexpressed on polarized macrophages. In this study, we constructed Pluronic® -F127 polymer and tannic acid (TA) based nanoparticles (F127-TA core nanoparticles) with varying mannose densities. The particle size of the optimized mannose-decorated F127-TA hybrid nanoparticles (MDNPs) was found to be ~ 265 nm with a negative zeta potential of ~ - 4.5 mV. No significant changes in the size and zeta potentials of nanoparticles were observed, which demonstrated structural integrity and stability of the nanoformulation. Physicochemical characteristics of MDNPs were evaluated by FTIR and TGA and demonstrated the presence of mannose units on surface nanoparticles. A mannose-dependent cellular targeting and uptake of MDNPs was found in U937 macrophages. The uptake process was found to vary directly with time and volume of MDNPs nanoparticles. The uptake pattern is higher in M2 than M1. This behavior was also evident from the instantaneous and superior binding profile of M2 macrophage lysate protein with MDNPs over that of M1 macrophage lysate protein. These results demonstrated that an appropriate mannose ligand density was confirmed, suggesting efficient targeting of M2. Altogether, these data support that the MDNPs formulation could serve as a targeted therapeutic guide in the generation of nanomedicine to treat various conditions as an anti-inflammation therapy.

Analytical methodology for studying cellular uptake, processing and localization of gold nanoparticles

Interactions of gold nanoparticles (AuNPs) with live cells are known to exert a great impact on their functions, including cell signalling, genomic, proteomic, and metabolomic processes. Modern analytical techniques applied to studying nanoparticle-cell interactions are to improve our understanding of the mode of action of AuNPs, which is essential for their approval in disease therapeutics. Such methods may vary depending on what step of particle internalization is in question, i.e., cellular uptake, intracellular transport (accompanying by changes in the chemical state), translocation to different cell compartments, interaction with relevant subcellular structures and localization. This review focuses on the implementation and critical assessment of advanced analytical methodologies to investigate the cellular processing of AuNPs. Also addressed is a sought-after issue of accounting in in-vitro studies for a chemical form in which the AuNPs enter the cell in vivo.

Formation of a protein corona influences the biological identity of nanomaterials

The development and testing of nanomaterials is an area of interest due to promising diagnostic and therapeutic applications in the treatment of diseases like cancer or cardiovascular disease. While extensive studies of the physicochemical properties of nanoparticles (NPs) are available, the investigation of the protein corona (PC) that is formed on NPs in biofluids is a relatively new area of research. The fact that few NPs are in clinical use indicates that the biological identity of NPs, which is in large part due to the PC formed in blood or other bodily fluids, may be altered in ways yet to be fully understood. Herein, we review the recent advances in PC research with the intent to highlight the current state of the field. We discuss the dynamic processes that control the formation of the PC on NPs, which involve the transient soft corona and more stable hard corona. Critical factors, like the environment and disease-state that affect the composition and stability of the PC are presented, with the intent of showcasing promising applications for utilizing the PC for disease diagnosis and the identification of disease-related biomarkers. This review summarizes the unique challenges presented by the nanoparticle corona and indicates future directions for investigation.

Probing Cellular Processes Using Engineered Nanoparticles

Nanoparticles, the building blocks of nanotechnology, have been widely utilized in various biomedical applications, such as detection, diagnosis, imaging, and therapy. However, another emerging, albeit under-represented, area is the employment of nanoparticles as tools to understand cellular processes (e.g., oxidative stress-induced signaling cascades). Such investigations have enormous potential to characterize a disease from a different perspective and unravel some new features that otherwise would have remained a mystery. In this review, we summarize the intrinsic biological properties of unmodified as well surface modified nanoparticles and discuss how such properties could be utilized to interrogate biological processes and provide a perspective for future evolution of this field.

Nanoparticle-Assisted Metabolomics

Understanding and harnessing the interactions between nanoparticles and biological molecules is at the forefront of applications of nanotechnology to modern biology. Metabolomics has emerged as a prominent player in systems biology as a complement to genomics, transcriptomics and proteomics. Its focus is the systematic study of metabolite identities and concentration changes in living systems. Despite significant progress over the recent past, important challenges in metabolomics remain, such as the deconvolution of the spectra of complex mixtures with strong overlaps, the sensitive detection of metabolites at low abundance, unambiguous identification of known metabolites, structure determination of unknown metabolites and standardized sample preparation for quantitative comparisons. Recent research has demonstrated that some of these challenges can be substantially alleviated with the help of nanoscience. Nanoparticles in particular have found applications in various areas of bioanalytical chemistry and metabolomics. Their chemical surface properties and increased surface-to-volume ratio endows them with a broad range of binding affinities to biomacromolecules and metabolites. The specific interactions of nanoparticles with metabolites or biomacromolecules help, for example, simplify metabolomics spectra, improve the ionization efficiency for mass spectrometry or reveal relationships between spectral signals that belong to the same molecule. Lessons learned from nanoparticle-assisted metabolomics may also benefit other emerging areas, such as nanotoxicity and nanopharmaceutics.

Protein corona in drug delivery for multimodal cancer therapy in vivo

The protein corona is inevitably formed on nanoparticles (NPs) when they are introduced in vivo and has been associated with a reduction in targeting yield, immune recognition and rapid blood clearance, leading to poor tumor accumulation. We have recently shown that it is possible to exploit the protein corona for drug delivery by exploiting it for loading and triggering the release of a photosensitizer Chlorin e6 (Ce6) for simultaneous photodynamic (PDT) and photothermal therapy (PTT) in vitro. Here, we extended our previous in vitro studies to evaluate its effectiveness in vivo. Specifically, we pre-formed the protein corona from mouse serum (MS) around gold nanorods (NRs) and loaded it with Ce6 to form NR-MS-Ce6. The intravenous delivery of NR-MS-Ce6 at a dose of 10 mg kg^-1 Au loaded with 9.63 μg kg^-1 Ce6 into tumor-bearing NCr nude mice resulted in their tumor accumulation reaching a peak concentration of 560.3 μg Au per kg tissue (0.0752% dose) within 6 h post-injection. Subsequent localized laser irradiation of the xenograft tumor resulted in a significant tumor temperature increase of 16.85 °C within 20 min. Combined with the simultaneous reactive oxygen species (ROS) production by Ce6 for PDT, complete tumor regression was achieved within 19 days with no tumor regrowth up to 31 days. Similar to other NPs, significant gold accumulation was observed in the major reticuloendothelial system (RES) organs, particularly the liver and spleen, although no acute toxicity was observed histologically 31 days post-treatment. Our results demonstrated for the first time an in vivo application of the protein corona around NPs in the loading and delivery of drugs in small animals. The ease of drug loading and the biocompatibility of the endogenous serum-based protein corona could make it useful for drug delivery and therapeutic applications instead of merely being considered as a biological artefact to be eliminated.

Cellular processing of gold nanoparticles: CE-ICP-MS evidence for the speciation changes in human cytosol

The cellular uptake of gold nanoparticles (AuNPs) may (or may not) affect their speciation, but information on the chemical forms in which the particles exist in the cell remains obscure. An analytical method based on the use of capillary electrophoresis hyphenated with inductively coupled plasma mass spectrometry (ICP-MS) has been proposed to shed light on the intracellular processing of AuNPs. It was observed that when being introduced into normal cytosol, the conjugates of 10-50 nm AuNPs with albumin evolved in human serum stayed intact. On the contrary, under simulated cancer cytosol conditions, the nanoconjugates underwent decomposition, the rate of which and the resulting metal speciation patterns were strongly influenced by particle size. The new peaks that appeared in ICP-MS electropherograms could be ascribed to nanosized species, as upon ultracentrifugation, they quantitatively precipitated whereas the supernatant showed only trace Au signals. Our present study is the first step to unravel a mystery of the cellular chemistry for metal-based nanomedicines.

Short-chained oligo(ethylene oxide)-functionalized gold nanoparticles: realization of significant protein resistance

Protein corona formed on nanomaterial surfaces play an important role in the bioavailability and cellular uptake of nanomaterials. Modification of surfaces with oligoethylene glycols (OEG) are a common way to improve the resistivity of nanomaterials to protein adsorption. Short-chain ethylene oxide (EO) oligomers have been shown to improve the protein resistance of planar Au surfaces. We describe the application of these EO oligomers for improved protein resistance of 30 nm spherical gold nanoparticles (AuNPs). Functionalized AuNPs were characterized using UV-Vis spectroscopy, dynamic light scattering (DLS), and zeta potential measurements. Capillary electrophoresis (CE) was used for separation and quantitation of AuNPs and AuNP-protein mixtures. Specifically, nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) was employed for the determination of equilibrium and rate constants for binding between citrate-stabilized AuNPs and two model proteins, lysozyme and fibrinogen. Semi-quantitative CE analysis was carried out for mixtures of EO-functionalized AuNPs and proteins, and results demonstrated a 2.5-fold to 10-fold increase in protein binding resistance to lysozyme depending on the AuNP surface functionalization and a 15-fold increase in protein binding resistance to fibrinogen for both EO oligomers examined in this study. Graphical abstract Using capillary electrophoresis, the addition of short-chained oligo(ethylene oxide) ligands to gold nanoparticles was shown to improve protein binding resistance up to 15-fold.

Protein-gold nanoparticle interactions and their possible impact on biomedical applications

In the past few years, concerns of protein-gold nanoparticles (AuNP) interaction have been continuously growing in numerous potential biomedical applications. Despite the advances in tunable size, shape and excellent biocompatibility, unpredictable adverse effects related with protein corona (PC) have critically affected physiological to therapeutic responses. The complexity and uncontrollability of AuNP-PC formation limited the clinical applications of AuNP, e.g. AuNP-based drug delivery systems or imaging agent. Thus, even intensive attempts have been made for in vitro characterizations of PC around AuNP, the extrapolation of these data into in vivo PC responses still lags far behind. However, with accumulated knowledge of corona formation and the unique properties of AuNP, we are now encouraged to move forward to seeking positive exploitations. Herein, we summarize recent researches on interaction of protein and AuNP, aiming at provide a comprehensive understanding of such interaction associated with subsequent biomedical impacts. Importantly, the emerging trends in exploiting of potential applications and opportunities based on protein-AuNP interaction were discussed as well.

STATEMENT OF SIGNIFICANCE

Gold nanoparticles (AuNPs) have shown great potentials in biomedical areas. However, its practical use is highly limited by protein corona, formed as a result of protein-AuNP interaction. This protein corona surrounding AuNPs is a new identity and the real substance that the organs and cells firstly encounter, and finally makes the behavior of AuNPs in vivo uncontrollable and unpredictable. Therefore, comprehensively understanding such interaction is of great significance for predicting the in vivo fate of AuNPs and for designing advanced AuNPs systems. In this review, we would provide a detailed description of protein-AuNP interaction and launch an interesting discussion on how to use such interaction for smart and controlled AuNPs delivery, which would be a topic of widespread interest.

Protein corona: a new approach for nanomedicine design

After administration of nanoparticle (NP) into biological fluids, an NP-protein complex is formed, which represents the "true identity" of NP in our body. Hence, protein-NP interaction should be carefully investigated to predict and control the fate of NPs or drug-loaded NPs, including systemic circulation, biodistribution, and bioavailability. In this review, we mainly focus on the formation of protein corona and its potential applications in pharmaceutical sciences such as prediction modeling based on NP-adsorbed proteins, usage of active proteins for modifying NP to achieve toxicity reduction, circulation time enhancement, and targeting effect. Validated correlative models for NP biological responses mainly based on protein corona fingerprints of NPs are more highly accurate than the models solely set up from NP properties. Based on these models, effectiveness as well as the toxicity of NPs can be predicted without in vivo tests, while novel cell receptors could be identified from prominent proteins which play important key roles in the models. The ungoverned protein adsorption onto NPs may have generally negative effects such as rapid clearance from the bloodstream, hindrance of targeting capacity, and induction of toxicity. In contrast, controlling protein adsorption by modifying NPs with diverse functional proteins or tailoring appropriate NPs which favor selective endogenous peptides and proteins will bring promising therapeutic benefits in drug delivery and targeted cancer treatment.

Current Challenges toward In Vitro Cellular Validation of Inorganic Nanoparticles

An impressive development has been achieved toward the production of well-defined "smart" inorganic nanoparticles, in which the physicochemical properties can be controlled and predicted to a high degree of accuracy. Nanoparticle design is indeed highly advanced, multimodal and multitargeting being the norm, yet we do not fully understand the obstacles that nanoparticles face when used in vivo. Increased cooperation between chemists and biochemists, immunologists and physicists, has allowed us to think outside the box, and we are slowly starting to understand the interactions that nanoparticles undergo under more realistic situations. Importantly, such an understanding involves awareness about the limitations when assessing the influence of such inorganic nanoparticles on biological entities and vice versa, as well as the development of new validation strategies.

Limiting the protein corona: A successful strategy for in vivo active targeting of anti-HER2 nanobody-functionalized nanostars

Gold nanoparticles hold great promise as anti-cancer theranostic agents against cancer by actively targeting the tumor cells. As this potential has been supported numerously during in vitro experiments, the effective application is hampered by our limited understanding and control of the interactions within complex in vivo biological systems. When these nanoparticles are exposed to a biological environment, their surfaces become covered with proteins and biomolecules, referred to as the protein corona, reducing the active targeting capabilities. We demonstrate a chemical strategy to overcome this issue by reducing the protein corona's thickness by blocking the active groups of the self-assembled monolayer on gold nanostars. An optimal blocking agent, 2-mercapto ethanol, has been selected based on charge and length of the carbon chain. By using a nanobody as a biological ligand of the human epidermal growth factor 2 receptor (HER2), the active targeting is demonstrated in vitro and in vivo in an experimental tumor model by using darkfield microscopy and photoacoustic imaging. In this study, we have established gold nanostars as a conceivable theranostic agent with a specificity for HER2-positive tumors.

Biological and environmental surface interactions of nanomaterials: characterization, modeling, and prediction

The understanding of nano-bio interactions is deemed essential in the design, application, and safe handling of nanomaterials. Proper characterization of the intrinsic physicochemical properties, including their size, surface charge, shape, and functionalization, is needed to consider the fate or impact of nanomaterials in biological and environmental systems. The characterizations of their interactions with surrounding chemical species are often hindered by the complexity of biological or environmental systems, and the drastically different surface physicochemical properties among a large population of nanomaterials. The complexity of these interactions is also due to the diverse ligands of different chemical properties present in most biomacromolecules, and multiple conformations they can assume at different conditions to minimize their conformational free energy. Often these interactions are collectively determined by multiple physical or chemical forces, including electrostatic forces, hydrogen bonding, and hydrophobic forces, and calls for multidimensional characterization strategies, both experimentally and computationally. Through these characterizations, the understanding of the roles surface physicochemical properties of nanomaterials and their surface interactions with biomacromolecules can play in their applications in biomedical and environmental fields can be obtained. To quantitatively decipher these physicochemical surface interactions, computational methods, including physical, statistical, and pharmacokinetic models, can be used for either analyses of large amounts of experimental characterization data, or theoretical prediction of the interactions, and consequent biological behavior in the body after administration. These computational methods include molecular dynamics simulation, structure-activity relationship models such as biological surface adsorption index, and physiologically-based pharmacokinetic models. WIREs Nanomed Nanobiotechnol 2017, 9:e1440. doi: 10.1002/wnan.1440 For further resources related to this article, please visit the WIREs website.

Multifunctional gold-based nanocomposites for theranostics

Although Au-particle potential in nanobiotechnology has been recognized for the last 15 years, new insights into the unique properties of multifunctional nanostructures have just recently started to emerge. Multifunctional gold-based nanocomposites combine multiple modalities to improve the efficacy of the therapeutic and diagnostic treatment of cancer and other socially significant diseases. This review is focused on multifunctional gold-based theranostic nanocomposites, which can be fabricated by three main routes. The first route is to create composite (or hybrid) nanoparticles, whose components enable diagnostic and therapeutic functions. The second route is based on smart bioconjugation techniques to functionalize gold nanoparticles with a set of different molecules, enabling them to perform targeting, diagnostic, and therapeutic functions in a single treatment procedure. Finally, the third route for multifunctionalized composite nanoparticles is a combination of the first two and involves additional functionalization of hybrid nanoparticles with several molecules possessing different theranostic modalities. This last class of multifunctionalized composites also includes fluorescent atomic clusters with multiple functionalities.

Metal Nanoparticles as Targeted Carriers Circumventing the Blood-Brain Barrier

Metal nanoparticles have been proposed as a carrier and a therapeutic agent in biomedical field because of their unique physiochemical properties. Due to these physicochemical properties, they can be used in different fields of biomedicine. In relation to this, plasmonic nanoparticles can be used for detection and photothermal destruction of tumor cells or toxic protein aggregates, and magnetic iron nanoparticles can be used for imaging and for hyperthermia of tumor cells. In addition, both therapy and imaging can be combined in one nanoparticle system, in a process called theranostics. Metal nanoparticles can be synthesized to modulate their size and shape, and conjugated with different ligands, which allow their application in drug delivery, diagnostics, and treatment of central nervous system diseases. This review is focused on the potential applications of metal nanoparticles and their capability to circumvent the blood-brain barrier (BBB). Although many articles have demonstrated delivery of metal nanoparticles to the brain by crossing the BBB after systemic administration, the percentage of the injected dose that reaches this organ is low in comparison to others, especially the liver and spleen. In connection with this drawback, we elaborate the architecture of the BBB and review possible mechanisms to cross this barrier by engineered nanoparticles. The potential uses of metal nanoparticles for treatment of disorders as well as related neurotoxicological considerations are also discussed. Finally, we bring up for discussion a direct and relatively simpler solution to the problem. We discuss this in detail after having proposed the use of the intranasal administration route as a way to circumvent the BBB. This route has not been extensively studied yet for metal nanoparticles, although it could be used as a research tool for mechanistic understanding and toxicity as well as an added value for medical practice.

Hepatoma derived growth factor (HDGF) dynamics in ovarian cancer cells

As a leading cause of cancer death among women, identification of pathophysiologically-relevant biomarkers for ovarian cancer is important. The heparin binding, hepatoma-derived growth factor (HDGF) is overexpressed in ovarian cancer cell lines and may have prognostic value, but the mechanism by which this predominantly nuclear protein is secreted or functions is unknown. In this study, we focused on the circumstances under which HDGF is released by cells and the functional relevance of extracellular HDGF in the context of ovarian cancer. Immunofluorescence imaging showed nuclear localization of HDGF in ovarian cells, but unlike what is reported for other cell types, HDGF was minimally secreted into the media. However, HDGF was passively released by necrotic and late apoptotic cells. Extracellular HDGF was functionally relevant as it stimulated phosphorylation of ERK 1/2 and P38 in both non-cancer and ovarian cancer cells, and enhanced cellular migration. Overall, our study uncovers a novel function of HDGF as a messenger of cellular condition (alarmin) which in-turn modulates cellular function-aspects that could be used as a biomarker for ovarian cancer.

Beyond the passive interactions at the nano-bio interface: evidence of Cu metalloprotein-driven oxidative dissolution of silver nanoparticles

Background

In a biological system, an engineered nanomaterial (ENM) surface is altered by adsorbed proteins that modify ENM fate and toxicity. Thus far, protein corona characterizations have focused on protein adsorption, interaction strength, and downstream impacts on cell interactions. Given previous reports of Ag ENM disruption of Cu trafficking, this study focuses on Ag ENM interactions with a model Cu metalloprotein, Cu(II) azurin. The study provides evidence of otherwise overlooked ENM-protein chemical reactivity within the corona: redox activity.

Results

Citrate-coated Ag ENMs of various sizes (10–40 nm) reacted with Cu(II) azurin resulted in an order of magnitude more dissolved ionic silver (Ag(I)(aq)) than samples of Ag ENMs only, ENMs mixed Cu(II) ions, or control proteins such as cytochrome c and horse radish peroxidase. This dramatic increase in ENM oxidative dissolution was observed even when Cu(II) azurin was combined with a diverse mixture of Escherchia coli proteins to mimic the complexity of the cellular conona. SDS PAGE results confirm that the multiprotein ENM corona includes azurin. A Cu(I)(aq) colorimetric indicator confirms Cu(II) azurin reduction upon interaction with Ag ENMs, but not with the addition of ionic silver, Ag(I)(aq).

Conclusions

Cu(II) azurin and 10–40 nm Ag ENMs react to catalyze Ag ENM oxidative dissolution and reduction of the model Cu metalloprotein. Results push the current evaluation of protein-ENM characterization beyond passive binding interactions and enable the proposal of a mechanism for reactivity between a model Cu metalloprotein and Ag ENMs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0160-6) contains supplementary material, which is available to authorized users.

Theranostic potential of gold nanoparticle-protein agglomerates

Owing to the ever-increasing applications, glittered with astonishing success of gold nanoparticles (Au NPs) in biomedical research as diagnostic and therapeutic agents, the study of Au NP-protein interaction seems critical for maximizing their theranostic efficiency, and thus demands comprehensive understanding. The mutual interaction of Au NPs and proteins at physiological conditions may result in the aggregation of protein, which can ultimately lead to the formation of Au NP-protein agglomerates. In the present article, we try to appreciate the plausible steps involved in the Au NP-induced aggregation of proteins and also the importance of the proteins' three-dimensional structures in the process. The Au NP-protein agglomerates can potentially be exploited for efficient loading and subsequent release of various therapeutically important molecules, including anticancer drugs, with the unique opportunity of incorporating hydrophilic as well as hydrophobic drugs in the same nanocarrier system. Moreover, the Au NP-protein agglomerates can act as 'self-diagnostic' systems, allowing investigation of the conformational state of the associated protein(s) as well as the protein-protein or protein-Au NP interaction within the agglomerates. Furthermore, the potential of these Au NP-protein agglomerates as a novel platform for multifunctional theranostic application along with exciting future-possibilities is highlighted here.

The functional dissection of the plasma corona of SiO₂-NPs spots histidine rich glycoprotein as a major player able to hamper nanoparticle capture by macrophages

A coat of strongly-bound host proteins, or hard corona, may influence the biological and pharmacological features of nanotheranostics by altering their cell-interaction selectivity and macrophage clearance. With the goal of identifying specific corona-effectors, we investigated how the capture of amorphous silica nanoparticles (SiO2-NPs; Ø = 26 nm; zeta potential = -18.3 mV) by human lymphocytes, monocytes and macrophages is modulated by the prominent proteins of their plasma corona. LC MS/MS analysis, western blotting and quantitative SDS-PAGE densitometry show that Histidine Rich Glycoprotein (HRG) is the most abundant component of the SiO2-NP hard corona in excess plasma from humans (HP) and mice (MP), together with minor amounts of the homologous Kininogen-1 (Kin-1), while it is remarkably absent in their Foetal Calf Serum (FCS)-derived corona. HRG binds with high affinity to SiO2-NPs (HRG Kd ∼2 nM) and competes with other plasma proteins for the NP surface, so forming a stable and quite homogeneous corona inhibiting nanoparticles binding to the macrophage membrane and their subsequent uptake. Conversely, in the case of lymphocytes and monocytes not only HRG but also several common plasma proteins can interchange in this inhibitory activity. The depletion of HRG and Kin-1 from HP or their plasma exhaustion by increasing NP concentration (>40 μg ml(-1) in 10% HP) lead to a heterogeneous hard corona, mostly formed by fibrinogen (Fibr), HDLs, LDLs, IgGs, Kallikrein and several minor components, allowing nanoparticle binding to macrophages. Consistently, the FCS-derived SiO2-NP hard corona, mainly formed by hemoglobin, α2 macroglobulin and HDLs but lacking HRG, permits nanoparticle uptake by macrophages. Moreover, purified HRG competes with FCS proteins for the NP surface, inhibiting their recruitment in the corona and blocking NP macrophage capture. HRG, the main component of the plasma-derived SiO2-NPs' hard corona, has antiopsonin characteristics and uniquely confers to these particles the ability to evade macrophage capture.