Protein corona change the drug release profile of nanocarriers: The “overlooked” factor at the nanobio interface

Ultrasound-sensitive nanoparticle aggregates for targeted drug delivery

Here we describe injectable, ultrasound (US)-responsive, nanoparticle aggregates (NPAs) that disintegrate into slow-release, nanoscale, drug delivery systems, which can be targeted to selective sites by applying low-energy US locally. We show that, unlike microbubble based drug carriers which may suffer from stability problems, the properties of mechanical activated NPAs, composed of polymer nanoparticles, can be tuned by properly adjusting the polymer molecular weight, the size of the nanoparticle precursors as well as the percentage of excipient utilized to hold the NPA together. We then apply this concept to practice by fabricating NPAs composed of nanoparticles loaded with Doxorubicin (Dox) and tested their ability to treat tumors via ultrasound activation. Mouse studies demonstrated significantly increased efficiency of tumor targeting of the US-activated NPAs compared to PLGA nanoparticle controls (with or without US applied) or intact NPAs. Importantly, when the Dox-loaded NPAs were injected and exposed to US energy locally, this increased ability to concentrate nanoparticles at the tumor site resulted in a significantly greater reduction in tumor volume compared to tumors treated with a 20-fold higher dose of the free drug.

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.

Interactions of organic nanoparticles with proteins in physiological conditions

The efficacy of nanoparticles in biomedical applications is strongly influenced by their ability to bind proteins onto their surface. The analysis of organic nanoparticles interacting with proteins in physiological conditions may help in the successful design of next generation nanoparticles with improved biodistributions and therapeutic performances.

Polymeric nanoparticles in development for treatment of pulmonary infectious diseases

Serious lung infections, such as pneumonia, tuberculosis, and chronic obstructive cystic fibrosis-related bacterial diseases, are increasingly difficult to treat and can be life-threatening. Over the last decades, an array of therapeutics and/or diagnostics have been exploited for management of pulmonary infections, but the advent of drug-resistant bacteria and the adverse conditions experienced upon reaching the lung environment urge the development of more effective delivery vehicles. Nanotechnology is revolutionizing the approach to circumventing these barriers, enabling better management of pulmonary infectious diseases. In particular, polymeric nanoparticle-based therapeutics have emerged as promising candidates, allowing for programmed design of multi-functional nanodevices and, subsequently, improved pharmacokinetics and therapeutic efficiency, as compared to conventional routes of delivery. Direct delivery to the lungs of such nanoparticles, loaded with appropriate antimicrobials and equipped with 'smart' features to overcome various mucosal and cellular barriers, is a promising approach to localize and concentrate therapeutics at the site of infection while minimizing systemic exposure to the therapeutic agents. The present review focuses on recent progress (2005-2015) important for the rational design of nanostructures, particularly polymeric nanoparticles, for the treatment of pulmonary infections with highlights on the influences of size, shape, composition, and surface characteristics of antimicrobial-bearing polymeric nanoparticles on their biodistribution, therapeutic efficacy, and toxicity. WIREs Nanomed Nanobiotechnol 2016, 8:842-871. doi: 10.1002/wnan.1401 For further resources related to this article, please visit the WIREs website.

A Versatile Theranostic Delivery Platform Integrating Magnetic Resonance Imaging/Computed Tomography, pH/cis-Diol Controlled Release, and Targeted Therapy

The functions of biomedical imaging, cancer targeting, and controlled release of therapeutic agents were integrated into a drug delivery platform to proof its diagnostic and therapeutic capabilities. This versatile nanocomposite is based on the strategic design of wormlike mesoporous silica nanocarriers that are decorated with extremely small iron oxide nanoparticles, having a prominent T1-weighted Magnetic Resonance Imaging (MRI) signal. The controlled release function was then achieved through the grafting of polyalcohol saccharide derivative ligands onto the surfaces of mesoporous silica nanoparticles to conjugate with boronic acid functionalized gold nanoparticles, which acted as the gate and the source of computed tomography (CT) signals. This versatile platform thus exhibited a MRI/CT dual imaging property drawing on the strong points to offset the weaknesses of each, rendering more accurate diagnosis. The capping of gold nanoparticles controlled with the hydrolysis of boronate ester bonds provides the reversible opening/closing process, avoiding further release of drug once the nanocomposite leaves the cell or tissue. To endow this platform with targeting ability, protocatechuic acid was utilized as a linker to connect folic acid with the boronic acid of the gold nanoparticles. The anchor of targeting moiety, folic acid, enriched this platform and enhanced the specific cellular uptake toward cells with folate receptor. This integrated drug delivery platform was then loaded with the antitumor agent doxorubicin, demonstrating its power for targeted delivery, bioimaging, and controlled release chemotherapy to reduce the undesired side effects of chemotherapy.

Protein corona: Opportunities and challenges

In contact with biological fluids diverse type of biomolecules (e.g., proteins) adsorb onto nanoparticles forming protein corona. Surface properties of the coated nanoparticles, in terms of type and amount of associated proteins, dictate their interactions with biological systems and thus biological fate, therapeutic efficiency and toxicity. In this perspective, we will focus on the recent advances and pitfalls in the protein corona field.

Time-evolution of in vivo protein corona onto blood-circulating PEGylated liposomal doxorubicin (DOXIL) nanoparticles

Nanoparticles (NPs) are instantly modified once injected in the bloodstream because of their interaction with the blood components. The spontaneous coating of NPs by proteins, once in contact with biological fluids, has been termed the 'protein corona' and it is considered to be a determinant factor for the pharmacological, toxicological and therapeutic profile of NPs. Protein exposure time is thought to greatly influence the composition of protein corona, however the dynamics of protein interactions under realistic, in vivo conditions remain unexplored. The aim of this study was to quantitatively and qualitatively investigate the time evolution of in vivo protein corona, formed onto blood circulating, clinically used, PEGylated liposomal doxorubicin. Protein adsorption profiles were determined 10 min, 1 h and 3 h post-injection of liposomes into CD-1 mice. The results demonstrated that a complex protein corona was formed as early as 10 min post-injection. Even though the total amount of protein adsorbed did not significantly change over time, the fluctuation of protein abundances observed indicated highly dynamic protein binding kinetics.

Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems

New achievements in the realm of nanoscience and innovative techniques of nanomedicine have moved micro/nanoparticles (MNPs) to the point of becoming actually useful for practical applications in the near future. Various differences between the extracellular and intracellular environments of cancerous and normal cells and the particular characteristics of tumors such as physicochemical properties, neovasculature, elasticity, surface electrical charge, and pH have motivated the design and fabrication of inventive "smart" MNPs for stimulus-responsive controlled drug release. These novel MNPs can be tailored to be responsive to pH variations, redox potential, enzymatic activation, thermal gradients, magnetic fields, light, and ultrasound (US), or can even be responsive to dual or multi-combinations of different stimuli. This unparalleled capability has increased their importance as site-specific controlled drug delivery systems (DDSs) and has encouraged their rapid development in recent years. An in-depth understanding of the underlying mechanisms of these DDS approaches is expected to further contribute to this groundbreaking field of nanomedicine. Smart nanocarriers in the form of MNPs that can be triggered by internal or external stimulus are summarized and discussed in the present review, including pH-sensitive peptides and polymers, redox-responsive micelles and nanogels, thermo- or magnetic-responsive nanoparticles (NPs), mechanical- or electrical-responsive MNPs, light or ultrasound-sensitive particles, and multi-responsive MNPs including dual stimuli-sensitive nanosheets of graphene. This review highlights the recent advances of smart MNPs categorized according to their activation stimulus (physical, chemical, or biological) and looks forward to future pharmaceutical applications.

Enrichment of immunoregulatory proteins in the biomolecular corona of nanoparticles within human respiratory tract lining fluid

When inhaled nanoparticles deposit in the lungs, they transit through respiratory tract lining fluid (RTLF) acquiring a biomolecular corona reflecting the interaction of the RTLF with the nanomaterial surface. Label-free snapshot proteomics was used to generate semi-quantitative profiles of corona proteins formed around silica (SiO2) and poly(vinyl) acetate (PVAc) nanoparticles in RTLF, the latter employed as an archetype drug delivery vehicle. The evolved PVAc corona was significantly enriched compared to that observed on SiO2 nanoparticles (698 vs. 429 proteins identified); however both coronas contained a substantial contribution from innate immunity proteins, including surfactant protein A, napsin A and complement (C1q and C3) proteins. Functional protein classification supports the hypothesis that corona formation in RTLF constitutes opsonisation, preparing particles for phagocytosis and clearance from the lungs. These data highlight how an understanding of the evolved corona is necessary for the design of inhaled nanomedicines with acceptable safety and tailored clearance profiles.

FROM THE CLINICAL EDITOR

Inhaled nanoparticles often acquire a layer of protein corona while they go through the respiratory tract. Here, the authors investigated the identity of these proteins. The proper identification would improve the understanding of the use of inhaled nanoparticles in future therapeutics.

Biodegradable polymeric nanostructures in therapeutic applications: opportunities and challenges

Biodegradable polymeric nanostructures (BPNs) have shown great promise in different therapeutic applications such as diagnosis, imaging, drug delivery, cosmetics, organ implants, and tissue engineering.

Proteomic and Lipidomic Analysis of Nanoparticle Corona upon Contact with Lung Surfactant Reveals Differences in Protein, but Not Lipid Composition

Pulmonary surfactant (PS) constitutes the first line of host defense in the deep lung. Because of its high content of phospholipids and surfactant specific proteins, the interaction of inhaled nanoparticles (NPs) with the pulmonary surfactant layer is likely to form a corona that is different to the one formed in plasma. Here we present a detailed lipidomic and proteomic analysis of NP corona formation using native porcine surfactant as a model. We analyzed the adsorbed biomolecules in the corona of three NP with different surface properties (PEG-, PLGA-, and Lipid-NP) after incubation with native porcine surfactant. Using label-free shotgun analysis for protein and LC-MS for lipid analysis, we quantitatively determined the corona composition. Our results show a conserved lipid composition in the coronas of all investigated NPs regardless of their surface properties, with only hydrophilic PEG-NPs adsorbing fewer lipids in total. In contrast, the analyzed NP displayed a marked difference in the protein corona, consisting of up to 417 different proteins. Among the proteins showing significant differences between the NP coronas, there was a striking prevalence of molecules with a notoriously high lipid and surface binding, such as, e.g., SP-A, SP-D, DMBT1. Our data indicate that the selective adsorption of proteins mediates the relatively similar lipid pattern in the coronas of different NPs. On the basis of our lipidomic and proteomic analysis, we provide a detailed set of quantitative data on the composition of the surfactant corona formed upon NP inhalation, which is unique and markedly different to the plasma corona.

Zeolite Nanoparticles for Selective Sorption of Plasma Proteins

The affinity of zeolite nanoparticles (diameter of 8-12 nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy.

Control of polymeric nanoparticle size to improve therapeutic delivery

As nanoparticle (NP)-mediated drug delivery research continues to expand, understanding parameters that govern NP interactions with the biological environment becomes paramount. The principles identified from the study of these parameters can be used to engineer new NPs, impart unique functionalities, identify novel utilities, and improve the clinical translation of NP formulations. One key design parameter is NP size. New methods have been developed to produce NPs with increased control of NP size between 10 and 200nm, a size range most relevant to physical and biochemical targeting through both intravascular and site-specific deliveries. Three notable techniques best suited for generating polymeric NPs with narrow size distributions are highlighted in this review: self-assembly, microfluidics-based preparation, and flash nanoprecipitation. Furthermore, the effect of NP size on the biological fate and transport properties at the molecular scale (protein-NP interactions) and the tissue and systemic scale (convective and diffusive transport of NPs) are analyzed here. These analyses underscore the importance of NP size control in considering clinical translation and assessment of therapeutic outcomes of NP delivery vehicles.

Advanced stimuli-responsive polymer nanocapsules with enhanced capabilities for payloads delivery

Recent progress in the design, preparation, and application of stimuli-responsive polymer nanocapsules with enhanced capabilities for payloads delivery are reviewed.

Biomolecular corona on nanoparticles: a survey of recent literature and its implications in targeted drug delivery

Achieving controlled cellular responses of nanoparticles (NP) is critical for the successful development and translation of NP-based drug delivery systems. However, precise control over the physicochemical and biological properties of NPs could become convoluted, diminished, or completely lost as a result of the adsorption of biomolecules to their surfaces. Characterization of the formation of the "biomolecular" corona has thus received increased attention due to its impact on NP and protein structure as well as its negative effect on NP-based targeted drug delivery. This review presents a concise survey of the recent literature concerning the importance of the NP-biomolecule corona and how it can be utilized to improve the in vivo efficacy of targeted delivery systems.