Exploiting the Protein Corona around Gold Nanorods for Loading and Triggered Release

Interaction of solid lipid nanoparticles with bovine serum albumin: physicochemical mechanistic insights

This study investigates the interaction of solid lipid nanoparticles (SLNs) with the transport protein bovine serum albumin (BSA) in terms of thermodynamic signatures, employing both spectroscopic and calorimetric techniques. When nanoparticles are exposed to biological media, proteins are adsorbed on their surfaces, leading to protein corona formation. Therefore, controlling the formation of the protein corona is essential for in vivo therapeutic efficacy. Although SLNs have previously been explored solely as potential nano-carriers for drug delivery, no prior efforts have been made to study their interactions with biomolecules from a biophysical and mechanistic perspective. SLNs are colloidal dispersions of the solid lipid in an aqueous solution stabilized by surfactants. Herein, a hot emulsification methodology was employed to formulate SLNs, and their interactions with BSA were analyzed. The SLNs were characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques to obtain information on their size, zeta potential, and shape. Fluorescence data suggested the presence of weak interactions between the SLNs and BSA. Static quenching is confirmed using time-correlated single-photon counting (TCSPC) experiments. Differential scanning calorimetric (DSC) and fluorescence spectroscopic experiments suggest the thermal stabilization of BSA by the SLNs. This stabilization results from the enhancement of the secondary structure of the protein without significantly altering the tertiary structure. Isothermal calorimetry (ITC) results suggest weak interactions between the SLNs and BSA, although not in a site-specific manner. Overall, mechanistic insights into lipid nanoparticle-protein interactions obtained from such studies efficiently overcome the hurdles associated with targeted drug delivery.

Fundamental Understanding of Bio-Nano Interface of Lysozyme on Psidium guajava Polyphenol Coated Silver Nanoparticles: Mechanistic Insights into the Effect of Protein Corona on the Antibacterial Efficacy

Recent times have witnessed revolutionary progress in the design and development of functionalized nanomaterials as promising tools for biomedicinal applications. However, the gap in the fundamental understanding of the "biological responses" of the nanomaterials after the formation of "protein-corona" when it is exposed to the body system has drawn a thin line from its discoveries to real clinical trial. In this article we have synthesized two different silver NPs capped with the polyphenols of Psidium guajava (guava) leaf extract and the other with one of its major polyphenolic groups, morin. Then, the formation of "bio-nano interface" of these synthesized AgNPs were illustrated in detail by taking the model carrier protein hen egg white lysozyme (HEWL). The formation of protein corona of HEWL on the surface of the AgNPs was revealed by the increase in the hydrodynamic size and the negative ξ-potential values as well as from the visualization of an ∼1 nm thick light gray layer of HEWL in the TEM micrographs. The binding interaction of surface adsorbed HEWL with the AgNPs was analyzed with various photophysical and molecular dynamics simulation (MD) techniques. HEWL interacted with these polyphenol-assisted AgNPs with moderate binding affinity (Kb ∼ 104 M-1) in a spontaneous manner with the structural integrity in its native conformation. Though several covalent forces are responsible for protein-NP interaction, electrostatic and hydrophobic forces of attraction played the major role in the complexation of HEWL with Guava L.-AgNPs and Morin-AgNPs, respectively. The lysozyme protein-corona on the synthesized polyphenol-assisted AgNPs altered their biological response as revealed from the reduction of antibacterial activity against pathological Gram-positive (E. faecalis) as well as Gram-negative (E. coli) bacterial strains in vitro.

Pulmonary Delivery of Nonviral Nucleic Acid-Based Vaccines With Spotlight on Gold Nanoparticles

Nucleic acid-based vaccines are leading-edge tools in developing next-generation preventative care. Much research has been done to convert vaccine gene therapy from an invasive to a noninvasive administration approach. The lung's large surface area and permeability make the pulmonary route a promising noninvasive delivery option for vaccines, with systemic and local applications. This review summarizes the challenges and the approaches that have been carried out to optimize the delivery of nucleic acids through the pulmonary route for vaccination purposes in recent years, with a spotlight on gold nanoparticles (AuNPs). Nonviral delivery systems have been widely explored, and AuNPs with their unique properties are emerging as promising tools for nucleic acid vaccines due to surface functionalization with mucus-penetrating polymers and targeting moieties that can bypass the barriers in pulmonary delivery and successfully deliver nucleic acids to the cells of interest. However, while promising, several challenges remain including selectively overcoming the lungs' immunological surveillance and adhesive mucus.

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.

Spatial mapping and quantitative evaluation of protein corona on PEGylated mesoporous silica particles by super-resolution fluorescence microscopy

Nanoparticles (NPs) adsorb serum proteins when exposed to biological fluids, forming a dynamic protein corona that has a profound impact on their overall biological profile and fate. Polyethylene glycol (PEG) modification is the most widely used strategy to mitigate and inhibit protein corona formation. Nevertheless, the accurate mapping and quantification of PEG inhibition effects on protein corona formation have scarcely been reported. Herein, we demonstrate the direct observation and quantification of protein corona adsorbed onto PEGylated mesoporous silica particles by direct stochastic optical reconstruction microscopy (dSTORM). The variation tendency of protein penetration depth in terms of PEG molecular weights and incubated time is investigated for the first time. The maximum penetration depths present slight increase with the prolonged incubation time, while they tend to remarkably decrease with increased chain length of modified PEG. Moreover, the co-localization of preformed protein corona with lysosomes and the destination of adsorbed protein are demonstrated. Our method provides important technical characterization information and in-depth understanding of protein corona adsorbed onto PEGylated mesoporous silica particles. This shines new light on the behaviors of silica materials in cells and may promote their practical applications in biomedicine.

Blood Compatibility of Drug-Inorganic Hybrid in Human Blood: Red Blood Cell Hitchhiking and Soft Protein Corona

A drug-delivery system consisting of an inorganic host-layered double hydroxide (LDH)-and an anticancer drug-methotrexate (MTX)-was prepared via the intercalation route (MTX-LDH), and its hematocompatibility was investigated. Hemolysis, a red blood cell counting assay, and optical microscopy revealed that the MTX-LDH had no harmful toxic effect on blood cells. Both scanning electron microscopy and atomic force microscopy exhibited that the MTX-LDH particles softly landed on the concave part inred blood cells without serious morphological changes of the cells. The time-dependent change in the surface charge and hydrodynamic radius of MTX-LDH in the plasma condition demonstrated that the proteins can be gently adsorbed on the MTX-LDH particles, possibly through protein corona, giving rise to good colloidal stability. The fluorescence quenching assay was carried out to monitor the interaction between MTX-LDH and plasma protein, and the result showed that the MTX-LDH had less dynamic interaction with protein compared with MTX alone, due to the capsule moiety of the LDH host. It was verified by a quartz crystal microbalance assay that the surface interaction between MTX-LDH and protein was reversible and reproducible, and the type of protein corona was a soft one, having flexibility toward the biological environment.

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.

Fabrication of hydroxyapatite-based nano-gold and nano-silver-doped bioceramic bone grafts: Enhanced mechanostructure, cell viability, and nuclear abnormality properties

In this study, nano-gold (nAu) and nano-silver (nAg) were doped at the molar ratios of Molar5-Molar30 to the Hydroxyapatite (HAp)-based bioceramic bone graft synthesized by the sol-gel method. The effects of nAu and nAg on structural, mechanical, cell viability, and nuclear abnormality of the synthesized bioceramic grafts were evaluated. The chemical and morphological properties of the bone grafts after production were examined through XRD and SEM-EDX analyses and mechanical tests. To determine the biocompatibility of the bone grafts, cell viability tests were performed using human fibroblast cells. In the cytotoxicity analyses, only HAp and HAp-nAu5 grafts did not show toxicological properties at any concentration, while HAp-nAg5 among the nAg-containing grafts gave the best results at the 200-100 μg/mL concentrations and showed significant cytotoxicity in human fibroblast cells. The other nAu-containing grafts showed toxicological properties in the concentration range of 200-50 μg/mL and nAg-containing grafts in the concentration range of 200-100 μg/mL against the negative control. The micronucleus (MN) analyses showed that the lowest total MN and L (lobbed) amounts, while the lowest total N (notched) amount, was obtained from the only HAp graft. It was found that the nAg-doped bone grafts gave higher total MN, L, and N amounts compared to the nAu-doped bone grafts. Furthermore, while the mean nuclear abnormality (NA) values of all grafts gave close results, the highest values were again obtained from the nAg-doped bone grafts.

Intravenous Hemostats: Foundation, Targeting, and Controlled-Release

Uncontrollable blood loss is the greatest cause of mortality in prehospital patients and the main source of disability and death in hospital care. Compared with external hemostats, intravenous hemostats are more appropriate for preventing and treating uncontrolled bleeding in vivo and large bleeding on the body surface. This Review initially establishes intravenous hemostats' response basis, including the coagulation mechanism, fibrinolytic pathway, and protein corona. Second, the study of advancement of intravenous hemostat targeting was expanded from two perspectives, cellular hemostatic agents and synthetic hemostatic agents. Meanwhile, after discussing the progress of controlled-release intravenous hemostats with platelets as the stimuli, this Review offers insight into the possibility of controlled-release intravenous hemostats with microenvironment as the stimuli, combining the studies of controlled-release targeted thrombolysis.

Studying the Interaction Behavior of Protein Coronated Gold Nanorods with Polystyrene Nanoplastics

The formation of protein corona and their modulatory effects on the physicochemical and biological activity of the nanomaterial is well established. The active protein corona on the nanoparticles can further mediate interactions with trace amounts of exogenous entities present in the systemic circulation. In the present study, we utilize an in vitro simulation system wherein, protein corona is strategically engineered by varying the serum concentration on a model nanoparticle i. e. cationic‐gold nanorods (GNRs). Quantitative analysis indicated that the 4 nm cationic GNRs can accumulate as high as ∼1 mg/mL protein corona upon incubation with serum. The size distribution pattern of the bound corona and their subsequent impact on the physicochemical properties of GNRs were determined. To understand how these coronated nanorods would interact with a potent pollutant, the second layer of interaction was further introduced by interacting the coronated‐GNRs with 1 ppm nanoplastic. The impact of differently functionalized polystyrene beads (plain, aminated, and carboxylated) on the core size, hydrodynamic diameter, surface charge, and optical properties of the coronated GNRs is highlighted. A complex interplay of several interactive forces and amino acid‐mediated binding of the GNRs to the styrene and benzene rings of the nanoplastic leads to the formation of a coronated‐GNR‐PS complex (>400 nm). Further, upon subjecting the hybrid‐conjugate system to acidic pH conditions (pH‐5.6 and 4.3), a considerable increase in protein leaching was observed. The novel approach of the present study aims to look into the layered interactive patterns for nanomaterials that are utilized for in vivo applications.

Chirality-Dependent Dynamic Evolution of the Protein Corona on the Surface of Quantum Dots

Elucidating the biological behavior of engineered nanoparticles, for example, the protein corona, is important for the development of safe and efficient nanomedicine, but our current understanding is still limited due to its highly dynamic nature and lack of adequate analytical tools. In the present work, we demonstrate the establishment of a fluorescence resonance energy transfer (FRET)-based platform for monitoring the dynamic evolution behavior of the protein corona in complex biological media. With human serum albumin and lysozyme as the model serum proteins, the protein exchange process of the preformed corona on the surface of chiral quantum dots (QDs) upon feeding either individual protein or human serum was monitored in situ by FRET. Important parameters characterizing the evolution process of protein corona could be obtained upon quantitative analysis of FRET data. Further combining real-time FRET monitoring with gel electrophoresis experiments revealed that the nature of the protein initially adsorbed on the surface of QDs significantly affects the subsequent dynamic exchange behavior of the protein corona. Furthermore, our results also revealed that only a limited proportion of proteins are involved in the protein exchange, and the exchange process exhibits a significant dependence on the surface chirality of QDs. This work demonstrates the feasibility of FRET as a powerful tool to exploit the dynamic evolution process of the protein corona, which can provide theoretical guidance for further design of advanced nanomaterials for biomedical applications.

The Yin and Yang of the protein corona on the delivery journey of nanoparticles

Nanoparticles-based drug delivery systems have attracted significant attention in biomedical fields because they can deliver loaded cargoes to the target site in a controlled manner. However, tremendous challenges must still be overcome to reach the expected targeting and therapeutic efficacy in vivo. These challenges mainly arise because the interaction between nanoparticles and biological systems is complex and dynamic and is influenced by the physicochemical properties of the nanoparticles and the heterogeneity of biological systems. Importantly, once the nanoparticles are injected into the blood, a protein corona will inevitably form on the surface. The protein corona creates a new biological identity which plays a vital role in mediating the bio-nano interaction and determining the ultimate results. Thus, it is essential to understand how the protein corona affects the delivery journey of nanoparticles in vivo and what we can do to exploit the protein corona for better delivery efficiency. In this review, we first summarize the fundamental impact of the protein corona on the delivery journey of nanoparticles. Next, we emphasize the strategies that have been developed for tailoring and exploiting the protein corona to improve the transportation behavior of nanoparticles in vivo. Finally, we highlight what we need to do as a next step towards better understanding and exploitation of the protein corona. We hope these insights into the "Yin and Yang" effect of the protein corona will have profound implications for understanding the role of the protein corona in a wide range of nanoparticles.

Biofunctionalized graphene oxide nanosheet for amplifying antitumor therapy: Multimodal high drug encapsulation, prolonged hyperthermal window, and deep-site burst drug release

Biofunctional surface-modification surpassed critical limitation of graphene oxide (GO) in biocompatibility and drug delivery efficiency, contributing to versatile biomedical applications. Here, a protein corona-bridged GO nanoplatform with high drug loading, longstanding hyperthermia, and controllable drug release, was engineered for amplified tumor therapeutic benefits. Structurally, GO surface was installed with phenylboronic acid (PBA) layer, on which iRGD conjugated apolipoprotein A-I (iRGD-apoA-I) was coordinated via boron electron-deficiency, to form the sandwich-like GO nanosheet (iAPG). The GO camouflaging by iRGD-apoA-I corona provided multimodal high doxorubicin (DOX) loading by π-π stacking and coordination, and generated a higher photothermal transformation efficiency simultaneously. In vitro studies demonstrated that iAPG significantly improved drug penetration and internalization, then achieved tumor-targeted DOX release through near-infrared (NIR) controlled endo/lysosome disruption. Moreover, iAPG mediated site-specific drug shuttling to produce a 3.53-fold enhancement of tumor drug-accumulation compared to the free DOX in vivo, and induced deep tumor penetration dramatically. Primary tumor ablation and spontaneous metastasis inhibition were further demonstrated with negligible side effects under optimal NIR. Taken together, our work provided multifunctional protein corona strategy to inorganic nanomaterials toward advantageous biomedical applications.

Artificial engineering of the protein corona at bio-nano interfaces for improved cancer-targeted nanotherapy

Nanoparticles (NPs) have been demonstrated in numerous applications as anticancer, antibacterial and antioxidant agents. Artificial engineering of protein interactions with NPs in biological systems is crucial to develop potential NPs for drug delivery and cancer nanotherapy. The protein corona (PC) on the NP surface, displays an interface between biomacromolecules and NPs, governing their pharmacokinetics and pharmacodynamics. Upon interaction of proteins with the NP surface, their surface features are modified and they can easily be removed from the circulation by the mononuclear phagocytic system (MPS). PC properties heavily depend on the biological microenvironment and NP surface physicochemical parameters. Based on this context, we have surveyed different approaches that have been used for artificial engineering of the PC composition on NP surfaces. We discuss the effects of NP size, shape, surface modifications (PEGylation, self-peptide, other polymers), and protein pre-coating on the PC properties. Additionally, other factors including protein source and structure, intravenous injection and the subsequent shear flow, plasma protein gradients, temperature and local heat transfer, and washing media are considered in the context of their effects on the PC properties and overall target cellular effects. Moreover, the effects of NP-PC complexes on cancer cells based on cellular interactions, organization of intracellular PC (IPC), targeted drug delivery (TDD) and regulation of burst drug release profile of nanoplatforms, enhanced biocompatibility, and clinical applications were discussed followed by challenges and future perspective of the field. In conclusion, this paper can provide useful information to manipulate PC properties on the NP surface, thus trying to provide a literature survey to shorten their shipping from preclinical to clinical trials and to lay the basis for a personalized PC.

Protein adsorption onto nanomaterials engineered for theranostic applications

The key role of biomolecule adsorption onto engineered nanomaterials for therapeutic and diagnostic purposes has been well recognized by the nanobiotechnology community, and our mechanistic understanding of nano-bio interactions has greatly advanced over the past decades. Attention has recently shifted to gaining active control of nano-bio interactions, so as to enhance the efficacy of nanomaterials in biomedical applications. In this review, we summarize progress in this field and outline directions for future development. First, we briefly review fundamental knowledge about the intricate interactions between proteins and nanomaterials, as unraveled by a large number of mechanistic studies. Then, we give a systematic overview of the ways that protein-nanomaterial interactions have been exploited in biomedical applications, including the control of protein adsorption for enhancing the targeting efficiency of nanomedicines, the design of specific protein adsorption layers on the surfaces of nanomaterials for use as drug carriers, and the development of novel nanoparticle array-based sensors based on nano-bio interactions. We will focus on particularly relevant and recent examples within these areas. Finally, we conclude this topical review with an outlook on future developments in this fascinating research field.

The effect of drug loading and multiple administration on the protein corona formation and brain delivery property of PEG-PLA nanoparticles

The presence of protein corona on the surface of nanoparticles modulates their physiological interactions such as cellular association and targeting property. It has been shown that α-mangostin (αM)-loaded poly(ethylene glycol)-poly(l-lactide) (PEG-PLA) nanoparticles (NP-αM) specifically increased low density lipoprotein receptor (LDLR) expression in microglia and improved clearance of amyloid beta (Aβ) after multiple administration. However, how do the nanoparticles cross the blood‒brain barrier and access microglia remain unknown. Here, we studied the brain delivery property of PEG-PLA nanoparticles under different conditions, finding that the nanoparticles exhibited higher brain transport efficiency and microglia uptake efficiency after αM loading and multiple administration. To reveal the mechanism, we performed proteomic analysis to characterize the composition of protein corona formed under various conditions, finding that both drug loading and multiple dosing affect the composition of protein corona and subsequently influence the cellular uptake of nanoparticles in b.End3 and BV-2 cells. Complement proteins, immunoglobulins, RAB5A and CD36 were found to be enriched in the corona and associated with the process of nanoparticles uptake. Collectively, we bring a mechanistic understanding about the modulator role of protein corona on targeted drug delivery, and provide theoretical basis for engineering brain or microglia-specific targeted delivery system.

Radioiodination of extravesicular surface constituents to study the biocorona, cell trafficking and storage stability of extracellular vesicles

BACKGROUND

Extracellular vesicles (EVs) are produced by all cell types and serve as biological packets delivering a wide variety of molecules for cell-to-cell communication. However, the biology of the EV extravesicular surface domain that we have termed EV 'biocorona' remains underexplored. Upon cell secretion, EVs possess an innate biocorona containing membrane integral and peripheral constituents that is modified by acquired constituents post secretion. This distinguishes EVs from synthetic nanoparticulate biomaterials that are limited to an adsorption-based, acquired biocorona.

METHODS

The EV biocorona molecular constituents were radiolabeled with 125I to study biocorona constituents and its surface dynamics. As example toolset applications, 125I-EVs were utilized to study EV cell trafficking and the stability of the EV biocorona during storage.

RESULTS

The biocorona of EVs consisted of proteins, lipids, DNA and RNA. The cellular uptake of 125I-EVs was temperature dependent and internalized 125I-EVs were rapidly recycled by cells. When 125I-EVs were stored in a purified state, they exhibited time and temperature dependent biocorona shedding and proteolytic degradation that was partially inhibited in the presence of serum.

CONCLUSION

The EV biocorona is complex and dynamic. Radiolabeling of the EV biocorona enables a unique platform methodology to study the biocorona and will facilitate unlocking EV's full clinical translation potential.

GENERAL SIGNIFICANCE

The EV biocorona affects EV mediated biological processes in health and disease. Acquiring knowledge of the EV biocorona composition, dynamics, stability and structure not only informs the diagnostic and therapeutic translation of EVs but also aids in designing biomimetic nanomaterials for drug delivery.

BSA-Coated Gold Nanorods for NIR-II Photothermal Therapy

The second near infrared window is considered to be the optimal optical window for medical imaging and therapy as its capability of deep tissue penetration. The preparation of the gold nanorods with long wavelength absorption and low cytotoxicity is still a challenge. A series gold nanorods with large aspect ratio have been synthesized. Strong plasma absorption in the second near infrared window from 1000 to 1300 nm could be observed. The biocompatibility of the synthesized gold nanorods is dramatically improved via coating by bovine serum albumin (BSA), while the optical properties of which remains. The breast cancer tumor-bearing mouse could be well treated by the prepared gold nanorods with the NIR-II light intensity as low as 0.75 W/cm². In summary, these results demonstrate the feasibility of using low illumination dose to treat tumor in the NIR-II region via the large aspect ratio gould nanoparticles.

Synthesis of NIR-II Absorbing Gelatin Stabilized Gold Nanorods and Its Photothermal Therapy Application against Fibroblast Histiocytoma Cells

The excellent photothermal properties of gold nanorods (Au-NRs) make them one of the most researched plasmonic photothermal nanomaterials. However, their biological applications have been hampered greatly due to surfactant-induced cytotoxicity. We herein report a simple synthesis of highly biocompatible gelatin stabilized Au-NRs (gelatin@Au-NRs) to address this issue. The optical and structural properties of the as-synthesized gelatin@Au-NRs were investigated by Zetasizer, Ultraviolet-Visible-Near Infrared (UV-Vis-NIR) spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared spectroscopy (FTIR). The as-synthesized gelatin@Au-NRs were highly crystalline and rod-like in shape with an average length and diameter of 66.2 ± 2.3 nm and 10 ± 1.6 nm, respectively. The as-synthesized gelatin@Au-NRs showed high stability in common biological media (phosphate buffer saline and Dulbecco’s Modified Eagle’s Medium) compared to CTAB capped Au-NRs. Similarly, the gelatin@Au-NRs showed an improved heat production and outstanding cell viability against two different cancer cell lines; KM-Luc/GFP (mouse fibroblast histiocytoma cell line) and FM3A-Luc (breast carcinoma cell line) compared to CTAB capped Au-NRs and PEG@Au-NRs. An in vitro photothermal therapy study against KM-Luc/GFP showed that gelatin@Au-NRs effectively destroys the cancer cells.

Death Pathways of Cancer Cells Modulated by Surface Molecule Density on Gold Nanorods

Necrosis induces strong inflammation with undesirable implications in clinics compared with apoptosis. Fortunately, the switch between necrosis and apoptosis could be realized by tailoring the appropriate structural properties of gold nano rods (GNRs) that could precisely modulate cell death pathways. Herein, the intracellular interaction between GNRs and organelles is monitored and it is found that lysosomes dominates necrosis/apoptosis evoking. Then the surface molecule density of GNRs, which is first defined as ρsurf. molecule (Nsurf. molecules /(a × π × Diameter × Length)), mediates lysosome activities as the membrane permeabilization (LMP), the Cathepsin B and D release, the cross-talk between lysosome and different organelles, which selectively evokes apoptosis or necrosis and the production of TNF-α from macrophages. GNRs with small ρsurf. molecule mainly induce apoptosis, while with large ρsurf. molecule they greatly contribute to necrosis. Interestingly, necrosis can be suppressed by GNRs with higher ρsurf. molecule due to the overexpression of key protease caspase 8, which cleaves the RIP1-RIP3 complex and activates caspase 3 followed by necrosis to apoptosis transition. This investigation indicates that the ρsurf. molecule greatly affects the utility of nanomaterials and different structural properties of nanomaterials have different implications in clinics.

pH-Responsive Hybrid Nanoparticles for Imaging Spatiotemporal pH Changes in Biofilm-Dentin Microenvironments

Engineering highly sensitive nanomaterials to monitor spatiotemporal pH changes has rather broad applications in studying various biological systems. Intraoral/biofilm-tooth pH is the single parameter that has demonstrated accurate assessment of dental caries risk, reflecting the summative integrated outcome of the complicated interactions between three etiological factors, namely, microorganisms/biofilm, diet/carbohydrates, and tooth/saliva/host. However, there is little to no technology/system capable of accurately probing simultaneously both the micro-pH profiles in dentin tissues and acidogenic oral biofilms and examining the pathophysiologic acid attacks with high spatial/temporal resolution. Therefore, a highly sensitive pH-responsive hybrid nanoparticle (pH-NP) is developed and coupled with an ex vivo tooth-biofilm caries model to simulate and study the key cariogenic determinants/steps. The pH-NP emits two distinct fluorescences with mutually inversely proportional intensities that vary accordingly to the proximity pH and with a ratiometric output sensitivity of 13.4-fold across a broad clinically relevant pH range of 3.0-8.0. Using [H⁺], in addition to pH, to calculate the "area-under-curve" corroborates the "minimum-pH" in semiquantifying the demineralizing potential in each biofilm-dentin zones/depth. The data mechanistically elucidates a two-pronged cariogenic effect of a popular-acidic-sweet-drink, in inundating the biofilm/tooth-system with H⁺ ions from both the drink and the metabolic byproducts of the biofilm.

The protein corona and its effects on nanoparticle-based drug delivery systems

In most cases, once nanoparticles (NPs) enter the blood, their surface is covered by biological molecules, especially proteins, forming a so-called protein corona (PC). As a result, what the cells of the body "see" is not the NPs as formulated by the chemists, but the PC. In this way, the PC can influence the effects of the NPs and even mask the desired effects of the NP components. While this can argue for trying to inhibit protein-nanomaterial interactions, encapsulating NPs in an endogenous PC may increase their clinical usefulness. In this review, we briefly introduce the concept of the PC, its formation and its effects on the behavior of NPs. We also discuss how to reduce the formation of PCs or exploit them to enhance NP functions. Studying the interactions between proteins and NPs will provide insights into their clinical activity in health and disease. STATEMENT OF SIGNIFICANCE: The formation of protein corona (PC) will affect the operation of nanoparticles (NPs) in vivo. Since there are many proteins in the blood, it is impossible to completely overcome the formation of PC. Therefore, the use of PCs to deliver drug is the best choice. De-opsonins adsorbed on NPs can reduce macrophage phagocytosis and cytotoxicity of NPs, and prolong their circulation in blood. Albumin, apolipoprotein and transferrin are typical de-opsonins. In present review, we mainly discuss how to optimize the delivery of nanoparticles through the formation of albumin corona, transferrin corona and apolipoprotein corona in vivo or in vitro.

Interdependency of influential parameters in therapeutic nanomedicine

Introduction:Current challenges to successful clinical translation of therapeutic nanomedicine have discouraged many stakeholders, including patients. Significant effort has been devoted to uncovering the reasons behind the less-than-expected success, beyond failures or ineffectiveness, of therapeutic nanomedicine products (e.g. cancer nanomedicine). Until we understand and address the factors that limit the safety and efficacy of NPs, both individually and in combination, successful clinical development will lag.Areas covered:This review highlights the critical roles of interdependent factors affecting the safety and therapeutic efficacy of therapeutic NPs for drug delivery applications.Expert opinion:Deep analysis of the current nanomedical literature reveals ahistory of unanticipated complexity by awide range of stakeholders including researchers. In the manufacture of nanomedicines themselves, there have been persistent difficulties with reproducibility and batch-to-batch variation. The unanticipated complexity and interdependency of nano-bio parameters has delayed our recognition of important factors affecting the safety and therapeutic efficacy of nanomedicine products. These missteps have had many factors including our lack of understanding of the interdependency of various factors affecting the biological identity and fate of NPs and biased interpretation of data. All these issues could raise significant concern regarding the reproducibility- or even the validity- of past publications that in turn formed the basis of many clinical trials of therapeutic nanomedicines. Therefore, the individual and combined effects of previously overlooked factors on the safety and therapeutic efficacy of NPs need to be fully considered in nanomedicine reports and product development.

Binding-Mediated Formation of Ribonucleoprotein Corona for Efficient Delivery and Control of CRISPR/Cas9

Protein coronae formed with nanoparticles confer several useful properties. However, the non-specific nature of protein corona formation makes it difficult to deliver specific proteins for therapeutic applications. Herein, we report on the construction of a new type of protein corona, termed binding-mediated protein corona. This new corona enables the efficient and controllable delivery of functional proteins, which is otherwise challenging for conventional protein coronae. We show the design and delivery of the ribonucleoprotein corona for the CRISPR/Cas9 system. Successful gene editing in human cell lines (Hela and HEK293) demonstrates the efficient delivery, high stability, low cytotoxicity, and well-controlled activity of the Cas9-guide RNA ribonucleoprotein. The binding-mediated protein corona strategy opens up new opportunities for therapeutic protein delivery.

Stealthiness and Hematocompatibility of Gold Nanoparticles with Pre-Formed Protein Corona

Studies have established that a serum protein corona pre-formed around gold nanorods (NRs) could be exploited for loading photosensitizers and chemotherapeutics to result in efficient cell kill in vitro with an extremely low dose. In this study, we further demonstrated that pre-forming a serum protein corona (PC) around citrate-capped NRs (NR-Cit) to form NR-PC conferred them stealth property and high hematocompatibility similar to the common strategy of PEGylating NRs, which would otherwise not be able to evade the immune system. Specifically, the NR-PC caused minimal complement activation with significantly lower formation of the terminal complement complex SC5b-9 measured in human serum containing NR-PC, and this resulted in low uptake by phagocytic U937 monocytes of 5.9% of the initial gold dose compared to 55.8% of NR-Cit. In addition, NR-PC exhibited very low hemolytic activity of less than 0.2% hemolysis with no observable effect on RBC morphology as opposed to 0.6% for NR-Cit at the same concentration of 1 nM NRs. Furthermore, we showed that the high hematocompatibility and stealth property of NR-PC were maintained even after the loading of small molecules, photosensitizer Chlorine e6 (Ce6), into the protein corona, thus further establishing the potential clinical relevance of exploiting the inevitably formed serum protein corona on nanoparticles as an effective delivery vector for small molecular therapeutics.

Research progress and application opportunities of nanoparticle-protein corona complexes

Nanoparticles (NPs) can be used to design for nanomedicines with different chemical surface properties owing to their size advantages and the capacity of specific delivery to targeted sites in organisms. The discovery of the presence of protein corona (PC) has changed our classical view of NPs, stimulating researchers to investigate the in vivo fate of NPs as they enter biological systems. Both NPs and PC have their specificity but complement each other, so they should be considered as a whole. The formation and characterization of NP-PC complexes provide new insights into the design, functionalization, and application of nanocarriers. Based on progress of recent researches, we reviewed the formation, characterization, and composition of the PC, and introduced those critical factors influencing PC, simultaneously expound the effect of PC on the biological function of NPs. Especially we put forward the opportunities and challenges when NP-PC as a novel nano-drug carrier for targeted applications. Furthermore, we discussed the pros versus cons of the PC, as well as how to make better PC in the future application of NPs.

Hyaluronic acid functionalized gold nanorods combined with copper-based therapeutic agents for chemo-photothermal cancer therapy

We herein report a hybrid nanocomposite (AuNRs-CTN@THA) which is based on hyaluronic acid-coated gold nanorods with loading of a copper complex through strong bonds. AuNRs-CTN@THA exhibits durable photothermal conversion capacity for pH-dominant and pH/temperature dual sensitive drug release, accomplishing synergetic antitumor efficacy and deep tumor penetration.

Hard and Soft Protein Corona of Nanomaterials: Analysis and Relevance

Upon contact with a biological milieu, nanomaterials tend to interact with biomolecules present in the media, especially proteins, leading to the formation of the so-called "protein corona". As a result of these nanomaterial-protein interactions, the bio-identity of the nanomaterial is altered, which is translated into modifications of its behavior, fate, and pharmacological profile. For biomedical applications, it is fundamental to understand the biological behavior of nanomaterials prior to any clinical translation. For these reasons, during the last decade, numerous publications have been focused on the investigation of the protein corona of many different types of nanomaterials. Interestingly, it has been demonstrated that the structure of the protein corona can be divided into hard and soft corona, depending on the affinity of the proteins for the nanoparticle surface. In the present document, we explore the differences between these two protein coronas, review the analysis techniques used for their assessment, and reflect on their relevance for medical purposes.

Can nanoparticles and nano‒protein interactions bring a bright future for insulin delivery?

Insulin therapy plays an essential role in the treatment of diabetes mellitus. However, frequent injections required to effectively control the glycemic levels lead to substantial inconvenience and low patient compliance. In order to improve insulin delivery, many efforts have been made, such as developing the nanoparticles (NPs)-based release systems and oral insulin. Although some improvements have been achieved, the ultimate results are still unsatisfying and none of insulin-loaded NPs systems have been approved for clinical use so far. Recently, nano‒protein interactions and protein corona formation have drawn much attention due to their negative influence on the in vivo fate of NPs systems. As the other side of a coin, such interactions can also be used for constructing advanced drug delivery systems. Herein, we aim to provide an insight into the advance and flaws of various NPs-based insulin delivery systems. Particularly, an interesting discussion on nano‒protein interactions and its potentials for developing novel insulin delivery systems is initiated.

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Insulin therapy plays essential roles in treating diabetes.

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Optimizing insulin delivery enhances insulin therapy.

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Nanoparticles are promising systems for delivery of insulin.

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Nano-protein interactions influence the delivery of nanoparticles.

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Nano-protein interactions can be used for advanced delivery of insulin.

Exploring the interactions between protein coronated CdSe quantum dots and nanoplastics

QDs after protein coronation can undergo sequential interaction with other pollutants which may alter the physiochemical property of the QDs and influence the stability of the corona proteins.

Drug Delivery Approaches for Doxorubicin in the Management of Cancers

Aim:

We aimed to review the drug delivery approaches including a novel drug delivery system of doxorubicin as an important anticancer drug.

Background:

Doxorubicin (DOX) is widely used against breast, uterine, ovarian, lung and cervical cancer. It is listed among the essential medicines by WHO and is thus a very important drug that can be used to fight against cancer. Despite its effectiveness, the use of the drug is limited due to its dose-dependent toxicity. Several studies based on the DOX have suggested the need for novel drug delivery formulations in the treatment of malignant and cancerous diseases due to its cytotoxic nature.

Objectives:

This review focuses on the different formulations of DOX which is a useful drug in the management of cancers, but associated with toxicity thus these approaches found applicability in the reduction of its toxicity.

Methods:

We searched the scientific database using cancer, DOX, and different formulations as the keywords. Here in only peer-reviewed research articles collected which were useful to our current work.

Results:

This study is based on an examination of the recent advancements of its novel drug delivery formulations. DOX hydrochloride is the first liposomal anticancer drug, administered via the intravenous route, and also clinically approved for the treatment of lymphomas, leukemias, and solid tumors. DOX is prepared into a liposomal formulation that contains polyethylene glycol (PEG) layer around DOX containing liposome made by pegylation process. DOX also formulated in nano-formulations which is also discussed herein led to reduced toxicity and increased efficacy.

Conclusion:

In the review, we described the significance of DOX in the form of different delivery approaches in the management of cancers with a reduction in the associated toxicity.

The Scattering of Gold Nanorods Combined with Differential Uptake, Paving a New Detection Method for Macrophage Subtypes Using Flow Cytometery

The strategy of identification for M1 and M2 macrophages both in vivo and in vitro would help to predict the health condition of the individual. Here, we introduced a solution to this problem with the advantage of both the phagocytic nature of macrophages and the scattering effect of gold nanorods (GNRs). The internalized GNRs, relating to their extent of intake, caused a conspicuous scattering profile at the red channel in flow cytometry, overruling the contribution of the cellular side scatters. This internalization is solely governed by the surface chemistry of GNRs. The PAH-GNRs showed maximum intake potency followed by Cit-, PSS-, and PEG-GNRs. On a substantial note, PAH-GNRs lead to differential uptake between M1 and M2 cells, with three times higher intake in M2 cells over M1. This is the first report of employing the scattering of unlabeled GNRs to discriminate M1 and M2 cell types using a flow cytometer.

A review of the current understanding of nanoparticles protein corona composition

Upon entering into the biological environments, the surface of the nanoparticles is immediately coated with proteins and form the so-called a protein corona due to which a nanoparticle changes its “synthetic” identity to a new “biological” identity. Different types of nanoparticles have different protein binding profiles, which is why they have different protein corona composition and therefore it cannot be said that there is a universal protein corona. The composition and amount of protein in the corona depends on the physical and chemical characteristics of the nanoparticles, the type of biological medium and the exposure time. Protein corona increases the diameter but also changes the composition of the surface of the nanoparticles and these changes affect biodistribution, efficacy, and toxicity of the nanoparticles.

Targeting Tumorigenicity of Breast Cancer Stem Cells Using SAHA/Wnt-b Catenin Antagonist Loaded Onto Protein Corona of Gold Nanoparticles

BACKGROUND

Among various theories for the origin of cancer, the "stemness phenotype model" suggests a dynamic feature for tumor cells in which non-cancer stem cells (non-CSCs) can inter-convert to CSCs. Differentiation with histone-deacetylase inhibitor, vorinostat (SAHA), can induce stem cells to differentiate as well as enforces non-CSCs to reprogram to CSCs. To avoid this undesirable effect, one can block the Wnt-βcatenin pathway. Thus, a dual delivery system of SAHA and a Wnt-βcatenin blocker will be beneficial in the induction of differentiation of CSCs. Protein corona (PC) formation in nanoparticle has a biologic milieu, and despite all problematic properties, it can be employed as a medium for dual loading of the drugs.

MATERIALS AND METHODS

We prepared sphere gold nanoparticles (GNPs) with human plasma protein corona loaded with SAHA as differentiating agent and PKF118-310 (PKF) as a Wnt-βcatenin antagonist. The MCF7 breast cancer stem cells were treated with NPs and the viability and differentiation were evaluated by Western blotting and sphere formation assay.

RESULTS

We found that both drugs loaded onto corona-capped GNPs had significant cytotoxicity in comparison to bare GNP-corona. Data demonstrated an increase in stem cell population and upregulation of mesenchymal marker, Snail by SAHA-loaded GNPs treatment; however, the combination of PKF loaded GNPs along with SAHA-loaded GNPs resulted in a reduction of stem cell populations and Snail marker. We have shown that in MCF7 and its CSCs simultaneous treatment with SAHA and PKF118-310 induced differentiation and inhibition of Snail induction.

CONCLUSION

Our study reveals the PC-coated GNPs as a biocompatible career for both hydrophilic (PKF) and hydrophobic (SAHA) agents which can decrease breast cancer stem cell populations along with reduced stemness state regression.

Tuning liposome composition to modulate corona formation in human serum and cellular uptake

Nano-sized objects such as liposomes are modified by adsorption of biomolecules in biological fluids. The resulting corona critically changes nanoparticle behavior at cellular level. A better control of corona composition could allow to modulate uptake by cells. Within this context, in this work, liposomes of different charge were prepared by mixing negatively charged and zwitterionic lipids to different ratios. The series obtained was used as a model system with tailored surface properties to modulate corona composition and determine the effects on liposome interactions with cells. Uptake efficiency and uptake kinetics of the different liposomes were determined by flow cytometry and fluorescence imaging. Particular care was taken in optimizing the methods to isolate the corona forming in human serum to prevent liposome agglomeration and to exclude residual free proteins, which could confuse the results. Thanks to the optimized methods, mass spectrometry of replicate corona isolations showed excellent reproducibility and this allowed semi-quantitative analysis to determine for each formulation the most abundant proteins in the corona. The results showed that by changing the fraction of zwitterionic and charged lipids in the bilayer, the amount and identity of the most abundant proteins adsorbed from serum differed. Interestingly, the formulations also showed very different uptake kinetics. Similar approaches can be used to tune lipid composition in a systematic way in order to obtain formulations with the desired corona and cell uptake behavior. STATEMENT OF SIGNIFICANCE: Liposomes and other nano-sized objects when introduced in biological fluids are known to adsorb biomolecules forming the so-called nanoparticle corona. This layer strongly affects the subsequent interactions of liposomes with cells. Here, by tuning lipid composition in a systematic way, a series of liposomes with tailored surface properties has been prepared to modulate the corona forming in human serum. Liposomes with very different cellular uptake kinetics have been obtained and their corona was identified in order to determine the most enriched proteins on the different formulations. By combining corona composition and uptake kinetics candidate corona proteins associated with reduced or increased uptake by cells can be identified and the liposome formulation can be tuned to obtain the desired uptake behavior.

Platinum(II) Drug-Loaded Gold Nanoshells for Chemo-Photothermal Therapy in Colorectal Cancer

In the present study, we utilize a poly[2-(N,N-dimethylamino)ethyl methacrylate]-poly(ε-caprolactone) (PDMA-PCL) micellar template-based gold nanoshell as a nanocarrier of a platinum-based chemotherapeutic drug, dichloro(1,2-diaminocyclohexane)platinum(II) (DACHPt). The gold nanoshells not only function as a drug delivery platform but also provide a remarkable photothermal effect, resulting in synergistically combined chemo-photothermal therapy. With the positively charged outstretched hydrophilic PDMA segments, chloroauric anions are attracted to the PDMA-PCL micellar surface and reduced to gold atoms in situ, forming small seeds that nucleate the subsequent growth of gold nanoshells. The DACHPt-loaded gold nanoshells possess strong absorption in the near-infrared (NIR) region and outstanding photothermal conversion effect; thus, they can promote a temperature increase that is sufficient to ablate tumor cells under NIR laser irradiation at a moderate power density (1 W/cm²). Furthermore, by exploiting the synergistic effects of platinum-based chemotherapy and photothermal therapy, the DACHPt-loaded gold nanoshells exhibited a profound inhibition of tumor growth compared to chemotherapy or photothermal therapy alone. Therefore, the platinum(II)-loaded gold nanoshells that we proposed herein may be a potential alternative for efficient curative therapy for colorectal cancer.

From spherical to bone-shaped gold nanoparticles-Time factor in the formation of Au NPs, their optical and photothermal properties

Using the same synthesis method, which was stopped at different time intervals, gold nanoparticles (Au NPs) with different shapes, from spherical to bone-shaped, were obtained. The physical properties of the synthesized Au NPs were investigated using transmission electron microscopy (TEM) combined with selected area electron diffraction patterns (SAED) and ultraviolet-visible spectroscopy (UV-vis). The TEM images showed, that stopping the synthesis after one minute lead to the formation of small spherical Au NPs, which evolved to the cubic shape, rods and bone-shaped Au NPs after 15 min, 30 min, 2 h, respectively. SAED patterns showed, that all the obtained Au NPs were crystalline. UV-vis spectra revealed, that the light absorbance depends on the shape of the Au NPs. Moreover, the effects of the time factor in the formation of Au NPs on the effective conversion of electromagnetic energy into thermal energy, was studied. Furthermore, simulated photothermal therapy (PTT) in combination with the obtained NPs, was done for two cancer cell lines SW480 and SW620. The mortality of cells after using the differently shaped Au NPs as photosensitizers is between 18 % and 52 % and increases with the decrease of the synthesis time.

Innate immune activation by conditioned medium of cancer cells following combined phototherapy with photosensitizer-loaded gold nanorods

Nanoparticle-based phototherapy has evolved to include immunotherapy as an effective treatment combination for cancers through inducing anti-cancer immune activation leading to downstream adaptive responses and immune protection.

Understanding the relevance of protein corona in nanoparticle-based therapeutics and diagnostics

Over the past few decades, nanoparticle-based therapeutic and diagnostic systems have gained immense recognition. A relative improvement in the status of the global cancer burden has been successful due to the advent of nanoparticle-based formulations. However, exposure of nanoparticles (NPs) to a real-time biological media alters its native identity due to the formation of the biomolecular corona. Such biological interactions hinder the efficiency of the NPs system. The parameters that govern such intricate interaction are generally overlooked while designing nano drugs and delivery systems (nano-DDS). Fabricating nano-DDS with prolonged circulation time, enhanced drug-loading, and release capacity along with efficient clearance, remain the primary concerns associated with cancer therapeutics. This present review firstly aims to summarize the critical aspects that influence protein coronation on therapeutic nanoparticles designed for anti-cancer therapy. The role of protein corona in modifying the overall pharmacodynamics of the nanoparticle-based DDS has been discussed. Further, the studies and patents that extend the concept of protein corona into diagnostics have been elaborated. An understanding of the pros and cons associated with protein coronation would not only help us gain better insights into the fabrication of effective anti-cancer drug-delivery systems but also improve the shortcomings related to the clinical translation of these nanotherapeutics.

Protein corona and its applications.

Gold nanorods–trypsin biocorona: a novel nano composite for in vitro cytotoxic activity towards MCF-7 and A-549 cancer cells

In the present work, we have synthesized cetyltrimethyl ammonium bromide (CTAB) capped gold nanorods (Au NRs) to evaluate apparent binding affinities for the adsorption of trypsin (TRP).

The Crown and the Scepter: Roles of the Protein Corona in Nanomedicine

Engineering nanomaterials are increasingly considered promising and powerful biomedical tools or devices for imaging, drug delivery, and cancer therapies, but few nanomaterials have been tested in clinical trials. This wide gap between bench discoveries and clinical application is mainly due to the limited understanding of the biological identity of nanomaterials. When they are exposed to the human body, nanoparticles inevitably interact with bodily fluids and thereby adsorb hundreds of biomolecules. A "biomolecular corona" forms on the surface of nanomaterials and confers a new biological identity for NPs, which determines the following biological events: cellular uptake, immune response, biodistribution, clearance, and toxicity. A deep and thorough understanding of the biological effects triggered by the protein corona in vivo will speed up their translation to the clinic. To date, nearly all studies have attempted to characterize the components of protein coronas depending on different physiochemical properties of NPs. Herein, recent advances are reviewed in order to better understand the impact of the biological effects of the nanoparticle-corona on nanomedicine applications. The recent development of the impact of protein corona formation on the pharmacokinetics of nanomedicines is also highlighted. Finally, the challenges and opportunities of nanomedicine toward future clinical applications are discussed.

Corona Composition Can Affect the Mechanisms Cells Use to Internalize Nanoparticles

Nanosized objects, such as nanoparticles and other drug carriers used in nanomedicine, once in contact with biological environments are modified by adsorption of biomolecules on their surface. The presence of this corona strongly affects the following interactions at cell and organism levels. It has been shown that corona proteins can be recognized by cell receptors. However, it is not known whether the composition of this acquired layer can also affect the mechanisms nanoparticles use to enter cells. This is of particular importance when considering that the same nanoparticles can form different coronas for instance in vitro when exposed to cells in different serum amounts or in vivo depending on the exposure or administration route. Thus, in this work, different coronas were formed on 50 nm silica by exposing them to different serum concentrations. The uptake efficiency in HeLa cells was compared, and the uptake mechanisms were characterized using transport inhibitors and RNA interference. The results showed that the nanoparticles were internalized by cells via different mechanisms when different coronas were formed, and only for one corona condition was uptake mediated by the LDL receptor. This suggested that coronas of different composition can be recognized differently by cell receptors, and this in turn leads to internalization via different mechanisms. Similar studies were performed using other cells, including A549 cells and primary HUVEC, and different nanoparticles, namely 100 nm liposomes and 200 nm silica. Overall, the results confirmed that the corona composition can affect the mechanisms of nanoparticle uptake by cells.

In situ detection of protein corona on single particle by rotational diffusivity

Since the formation of protein corona inevitably leads to an increase in the particle size, it is important to develop technologies enabling in situ monitoring of the size change of nanoparticles. Traditional diffusion-based methods for particle size measurement focused on the translational diffusion coefficient; however, the detection sensitivity can be improved by determining the rotational diffusion coefficient, which has a cubic dependence on the particle radius. Here, using an optically anisotropic gold nanorod as the rotational probe and using high-speed dark-field microscopy, we can extract the rotational diffusion coefficient of a single nanorod and monitor the size change induced by the formation of protein corona in situ in real time. We successfully determined the thermodynamic parameters for the interactions between AuNRs with BSA and fibrinogen, and also studied corona formation in complex media and with AuNRs with different surface chemistry. This work would provide new avenues for the study of interactions between nanomedicines and proteins.

Impact of Protein Corona in Nanoflare-Based Biomolecular Detection and Quantification

Selective detection and precise quantification of biomolecules in intracellular settings play a pivotal role in the diagnostics and therapeutics of diseases, including various cancers and infectious epidemics. Because of this clinical relevance, nanoprobes with high sensitivity, wide tunability, and excellent biological stability have become of high demand. In particular, nanoflares based on gold nanoparticles have emerged as an attractive candidate for intracellular detection due to their efficient cellular uptake, enhanced binding affinity with complementary targets, and improved biological compatibility. However, nanoprobes, including these nanoflares, are known to be susceptible to the adsorption of proteins present in the biological environment, which leads to the formation of a so-called protein corona layer on their surface, leading to an altered targeting efficiency and cellular uptake. In this work, we leverage the nanoflares platform to demonstrate the effect of protein corona on biomolecular detection, quantification, as well as biological stability against enzymatic degradation. Nanoflares incubated in a biologically relevant concentration of serum albumin proteins (0.50 wt %) were shown to result in more than 20% signal reduction in target detection, with a decrease varying proportionally with the protein concentrations. In addition, similar signal reduction was observed for different serum proteins, and PEG backfilling was found to be ineffective in mitigating the negative impact induced by the corona formation. Furthermore, nuclease resistance in nanoflares was also severely compromised by the presence of the corona shell (∼2-fold increase in hydrolysis activity). This work demonstrates the consequences of an in situ formed protein corona layer on molecular detection/quantification and biological stability of nanoflares in the presence of nuclease enzymes, highlighting the importance of calibrating similar nanoprobes in proper biological media to improve the accuracy of molecular detection and quantification.