Biological recognition of graphene nanoflakes

Nanoparticle-Protein Corona-Based Tissue Proteomics for the Aging Mouse Proteome Atlas

Highly abundant proteins present in biological fluids and tissues significantly interfere with low-abundance protein identification by mass spectrometry (MS), limiting proteomic depth and hindering protein biomarker discovery. Herein, to enhance the coverage of tissue proteomics, we developed a nanoparticle-protein corona (NP-PC)-based method for the aging mouse proteome atlas. Based on this method, we investigated the complexity of life process of 5 major organs, including the heart, liver, spleen, lungs, and kidneys, from 4 groups of mice at different ages. Compared with the conventional strategy, NP-PC-based proteomics significantly increased the number of identified protein groups in the heart (from 3007 to 3927; increase of 30.6%), liver (from 2982 to 4610; increase of 54.6%), spleen (from 5047 to 7351; increase of 45.7%), lungs (from 4984 to 6903; increase of 38.5%), and kidneys (from 3550 to 5739; increase of 61.7%), and we identified a total of 10 104 protein groups. The overall data indicated that 3-week-old mice showed more differences compared with the other three age groups. The proteins of amino acid-related metabolism were increased in aged mice compared with those in the 3-week-old mice. Protein-related infections were increased in the spleen of the aged mice. Interestingly, the spliceosome-related pathway significantly changed from youth to elders in the liver, spleen, and lungs, indicating the vital role of the spliceosome during the aging process. Our established aging mouse organ proteome atlas provides comprehensive insights into understanding the aging process, and it may help in prevention and treatment of age-related diseases.

Graphene Oxide Nanosheets Toxicity in Mice Is Dependent on Protein Corona Composition and Host Immunity

Two-dimension graphene oxide (GO) nanosheets with high and low serum protein binding profiles (high/low hard-bound protein corona/HChigh/low) are used in this study as model materials and screening tools to investigate the underlying roles of the protein corona on nanomaterial toxicities in vivo. We proposed that the in vivo biocompatibility/nanotoxicity of GO is protein corona-dependent and host immunity-dependent. The hypothesis was tested by injecting HChigh/low GO nanosheets in immunocompetent ICR/CD1 and immunodeficient NOD-scid II2rγnull mice and performed histopathological and hematological evaluation studies on days 1 and 14 post-injection. HClow GO induced more severe acute lung injury compared to HChigh GO in both immunocompetent and immunodeficient mice, with the effect being particularly pronounced in immunocompetent animals. Additionally, HClow GO caused more significant liver injury in both types of mice, with immunodeficient mice being more susceptible to its hepatotoxic effects. Moreover, administration of HClow GO resulted in increased hematological toxicity and elevated levels of serum pro-inflammatory cytokines in immunocompromised and immunocompetent mice, respectively. Correlation studies were conducted to explore the impact of distinct protein corona compositions on resulting toxicities in both immunocompetent and immunodeficient mice. This facilitated the identification of consistent patterns, aligning with those observed in vitro, thus indicating a robust in vitro-in vivo correlation. This research will advance our comprehension of how hard corona proteins interact with immune cells, leading to toxicity, and will facilitate the development of improved immune-modulating nanomaterials for therapeutic purposes.

Surface property and in vitro toxicity effect of insoluble particles given by protein corona: Implication for PM cytotoxicity assessment

In vitro toxicological assessment helps explore key fractions of particulate matter (PM) in association with the toxic mechanism. Previous studies mainly discussed the toxicity effects of the water-soluble and organic-soluble fractions of PM. However, the toxicity of insoluble fractions is relatively poorly understood, and the adsorption of proteins is rarely considered. In this work, the formation of protein corona on the surface of insoluble particles during incubation in a culture medium was investigated. It was found that highly abundant proteins in fetal bovine serum were the main components of the protein corona. The adsorbed proteins increased the dispersion stability of insoluble particles. Meanwhile, the leaching concentrations of some metal elements (e.g., Cu, Zn, and Pb) from PM increased in the presence of proteins. The toxicity effects and potential mechanisms of the PM insoluble particle-protein corona complex on macrophage cells RAW264.7 were discussed. The results revealed that the PM insoluble particle-protein corona complex could influence the phagosome pathway in RAW264.7 cells. Thus, it promoted the intracellular reactive oxygen species generation and induced a greater degree of cell differentiation, significantly altering cell morphology. Consequently, this work sheds new light on the combination of insoluble particles and protein corona in terms of PM cytotoxicity assessment.

Sources of biases in the in vitro testing of nanomaterials: the role of the biomolecular corona

The biological fate of nanomaterials (NMs) is driven by specific interactions through which biomolecules, naturally adhering onto their surface, engage with cell membrane receptors and intracellular organelles. The molecular composition of this layer, called the biomolecular corona (BMC), depends on both the physical-chemical features of the NMs and the biological media in which the NMs are dispersed and cells grow. In this work, we demonstrate that the widespread use of 10% fetal bovine serum in an in vitro assay cannot recapitulate the complexity of in vivo systemic administration, with NMs being transported by the blood. For this purpose, we undertook a comparative journey involving proteomics, lipidomics, high throughput multiparametric in vitro screening, and single molecular feature analysis to investigate the molecular details behind this in vivo/in vitro bias. Our work indirectly highlights the need to introduce novel, more physiological-like media closer in composition to human plasma to produce realistic in vitro screening data for NMs. We also aim to set the basis to reduce this in vitro-in vivo mismatch, which currently limits the formulation of NMs for clinical settings.

Environmental and Health Impacts of Graphene and Other Two-Dimensional Materials: A Graphene Flagship Perspective

Two-dimensional (2D) materials have attracted tremendous interest ever since the isolation of atomically thin sheets of graphene in 2004 due to the specific and versatile properties of these materials. However, the increasing production and use of 2D materials necessitate a thorough evaluation of the potential impact on human health and the environment. Furthermore, harmonized test protocols are needed with which to assess the safety of 2D materials. The Graphene Flagship project (2013-2023), funded by the European Commission, addressed the identification of the possible hazard of graphene-based materials as well as emerging 2D materials including transition metal dichalcogenides, hexagonal boron nitride, and others. Additionally, so-called green chemistry approaches were explored to achieve the goal of a safe and sustainable production and use of this fascinating family of nanomaterials. The present review provides a compact survey of the findings and the lessons learned in the Graphene Flagship.

Adhesion States Greatly Affect Cellular Susceptibility to Graphene Oxide: Therapeutic Implications for Cancer Metastasis

Graphene oxide (GO) has received increasing attention in the life sciences because of its potential for various applications. Although GO is generally considered biocompatible, it can negatively impact cell physiology under some circumstances. Here, we demonstrate that the cytotoxicity of GO greatly varies depending on the cell adhesion states. Human HCT-116 cells in a non-adhered state were more susceptible to GO than those in an adherent state. Apoptosis was partially induced by GO in both adhered and non-adhered cells to a similar extent, suggesting that apoptosis induction does not account for the selective effects of GO on non-adhered cells. GO treatment rapidly decreased intracellular ATP levels in non-adhered cells but not in adhered ones, suggesting ATP depletion as the primary cause of GO-induced cell death. Concurrently, autophagy induction, a cellular response for energy homeostasis, was more evident in non-adhered cells than in adhered cells. Collectively, our observations provide novel insights into GO's action with regard to cell adhesion states. Because the elimination of non-adhered cells is important in preventing cancer metastasis, the selective detrimental effects of GO on non-adhered cells suggest its therapeutic potential for use in cancer metastasis.

Soluble Nanographene C222: Synthesis and Applications for Synergistic Photodynamic/Photothermal Therapy

Nanographene C222, which consists of a planar graphenic plane containing 222 carbon atoms, holds the record as the largest planar nanographene synthesized to date. However, its complete insolubility makes the processing of C222 difficult. Here we addressed this issue by introducing peripheral substituents perpendicular to the graphene plane, effectively disrupting the interlayer stacking and endowing C222 with good solubility. We also found that the electron-withdrawing substituents played a crucial role in the cyclodehydrogenation process, converting the dendritic polyphenylene precursor to C222. After disrupting the interlayer stacking, the introduction of only a few peripheral carboxylic groups allowed C222 to dissolve in phosphate buffer saline, reaching a concentration of up to 0.5 mg/mL. Taking advantage of the good photosensitizing and photothermal properties of the inner C222 core, the resulting water-soluble C222 emerged as a single-component agent for both photothermal and photodynamic tumor therapy, exhibiting an impressive tumor inhibition rate of 96%.

The gut microbiome meets nanomaterials: exposure and interplay with graphene nanoparticles

Graphene-based nanoparticles are widely applied in many technology and science sectors, raising concerns about potential health risks. Emerging evidence suggests that graphene-based nanomaterials may interact with microorganisms, both pathogens and commensal bacteria, that dwell in the gut. This review aims to demonstrate the current state of knowledge on the interplay between graphene nanomaterials and the gut microbiome. In this study, we briefly overview nanomaterials, their usage and the characteristics of graphene-based nanoparticles. We present and discuss experimental data from in vitro studies, screening tests on small animals and rodent experiments related to exposure and the effects of graphene nanoparticles on gut microbiota. With this in mind, we highlight the reported crosstalk between graphene nanostructures, the gut microbial community and the host immune system in order to shed light on the perspective to bear on the biological interactions. The studies show that graphene-based material exposure is dosage and time-dependent, and different derivatives present various effects on host bacteria cells. Moreover, the route of graphene exposure might influence a shift in the gut microbiota composition, including the alteration of functions and diversity and abundance of specific phyla or genera. However, the mechanism of graphene-based nanomaterials' influence on gut microbiota is poorly understood. Accordingly, this review emphasises the importance of studies needed to establish the most desirable synthesis methods, types of derivatives, properties, and safety aspects mainly related to the routes of exposure and dosages of graphene-based nanomaterials.

Size effect of graphene oxide from quantum dot to nanoflake on the mobility of nanoplastics in seawater-saturated sand

Marine sedimentary environment serves as an important sink of terrigenous nanoplastics (NP) and graphene oxides (GO). In this study, we discovered that GO of varying sizes exhibited distinct binding modes with 200 nm NP in 35 practical salinity unit (PSU) seawater, resulting in varying impacts on the mobility of NP in porous media. GO-8, with a size of 8±2 nm, firmly adhered to the surface of NP and formed stable primary heterogeneous aggregates, which promoted NP mobility and increased the mass recovery of effluent (Meff) from 24.74% to 31.08%. GO-250 (246±10 nm) partly enveloped NP and only slightly increased the volume of heteroaggregates, which had minimal effect on NP transport. Conversely, GO-850 (855±55 nm) wrapped numerous NP particles to form large secondary heteroaggregates that clung to sand surfaces, providing additional attachment sites for NP, resulting in complete inhibition of NP mobility in porous media (Meff = 0%). In brackish water with 3.5 PSU, all GO-8, GO-250 and GO-850 achieved enhanced mobility of NP, with Meff increasing from 50.35% to 85.62%, 69.45% and 75.41%, respectively. The results indicate that GO size effects on NP mobility are also salinity-dependent.

The influence of protein corona on Graphene Oxide: implications for biomedical theranostics

Graphene-based nanomaterials have attracted significant attention in the field of nanomedicine due to their unique atomic arrangement which allows for manifold applications. However, their inherent high hydrophobicity poses challenges in biological systems, thereby limiting their usage in biomedical areas. To address this limitation, one approach involves introducing oxygen functional groups on graphene surfaces, resulting in the formation of graphene oxide (GO). This modification enables improved dispersion, enhanced stability, reduced toxicity, and tunable surface properties. In this review, we aim to explore the interactions between GO and the biological fluids in the context of theranostics, shedding light on the formation of the "protein corona" (PC) i.e., the protein-enriched layer that formed around nanosystems when exposed to blood. The presence of the PC alters the surface properties and biological identity of GO, thus influencing its behavior and performance in various applications. By investigating this phenomenon, we gain insights into the bio-nano interactions that occur and their biological implications for different intents such as nucleic acid and drug delivery, active cell targeting, and modulation of cell signalling pathways. Additionally, we discuss diagnostic applications utilizing biocoronated GO and personalized PC analysis, with a particular focus on the detection of cancer biomarkers. By exploring these cutting-edge advancements, this comprehensive review provides valuable insights into the rapidly evolving field of GO-based nanomedicine for theranostic applications.

Nanoparticles-mediated ion channels manipulation: From their membrane interactions to bioapplications

Ion channels are transmembrane proteins ubiquitously expressed in all cells that control various ions (e.g. Na⁺, K⁺, Ca²⁺ and Cl^- etc) crossing cellular plasma membrane, which play critical roles in physiological processes including regulating signal transduction, cell proliferation as well as excitatory cell excitation and conduction. Abnormal ion channel function is usually associated with dysfunctions and many diseases, such as neurodegenerative disorders, ophthalmic diseases, pulmonary diseases and even cancers. The precise regulation of ion channels not only helps to decipher physiological and pathological processes, but also is expected to become cutting-edge means for disease treatment. Recently, nanoparticles-mediated ion channel manipulation emerges as a highly promising way to meet the increasing requirements with respect to their simple, efficient, precise, spatiotemporally controllable and non-invasive regulation in biomedicine and other research frontiers. Thanks the advantages of their unique properties, nanoparticles can not only directly block the pore sites or kinetics of ion channels through their tiny size effect, and perturb active voltage-gated ion channel by their charged surface, but they can also act as antennas to conduct or enhance external physical stimuli to achieve spatiotemporal, precise and efficient regulation of various ion channel activities (e.g. light-, mechanical-, and temperature-gated ion channels etc). So far, nanoparticles-mediated ion channel regulation has shown potential prospects in many biomedical fields at the interfaces of neuro- and cardiovascular modulation, physiological function regeneration and tumor therapy et al. Towards such important fields, in this typical review, we specifically outline the latest studies of different types of ion channels and their activities relevant to the diseases. In addition, the different types of stimulation responsive nanoparticles, their interaction modes and targeting strategies towards the plasma membrane ion channels will be systematically summarized. More importantly, the ion channel regulatory methods mediated by functional nanoparticles and their bioapplications associated with physiological modulation and therapeutic development will be discussed. Last but not least, current challenges and future perspectives in this field will be covered as well.

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.

Could artificial intelligence revolutionize the development of nanovectors for gene therapy and mRNA vaccines?

Gene therapy enables the introduction of nucleic acids like DNA and RNA into host cells, and is expected to revolutionize the treatment of a wide range of diseases. This growth has been further accelerated by the discovery of CRISPR/Cas technology, which allows accurate genomic editing in a broad range of cells and organisms in vitro and in vivo. Despite many advances in gene delivery and the development of various viral and non-viral gene delivery vectors, the lack of highly efficient non-viral systems with low cellular toxicity remains a challenge. The application of cutting-edge technologies such as artificial intelligence (AI) has great potential to find new paradigms to solve this issue. Herein, we review AI and its major subfields including machine learning (ML), neural networks (NNs), expert systems, deep learning (DL), computer vision and robotics. We discuss the potential of AI-based models and algorithms in the design of targeted gene delivery vehicles capable of crossing extracellular and intracellular barriers by viral mimicry strategies. We finally discuss the role of AI in improving the function of CRISPR/Cas systems, developing novel nanobots, and mRNA vaccine carriers.

Machine learning in the identification, prediction and exploration of environmental toxicology: Challenges and perspectives

Over the past few decades, data-driven machine learning (ML) has distinguished itself from hypothesis-driven studies and has recently received much attention in environmental toxicology. However, the use of ML in environmental toxicology remains in the early stages, with knowledge gaps, technical bottlenecks in data quality, high-dimensional/heterogeneous/small-sample data analysis and model interpretability, and a lack of an in-depth understanding of environmental toxicology. Given the above problems, we review the recent progress in the literature and highlight state-of-the-art toxicological studies using ML (such as learning and predicting toxicity in complicated biosystems and multiple-factor environmental scenarios of long-term and large-scale pollution). Beyond predicting simple biological endpoints by integrating untargeted omics and adverse outcome pathways, ML development should focus on revealing toxicological mechanisms. The integration of data-driven ML with other methods (e.g., omics analysis and adverse outcome pathway frameworks) endows ML with widely promising application in revealing toxicological mechanisms. High-quality databases and interpretable algorithms are urgently needed for toxicology and environmental science. Addressing the core issues and future challenges for ML in this review may narrow the knowledge gap between environmental toxicity and computational science and facilitate the control of environmental risk in the future.

Biomolecular Corona Stability in Association with Plasma Cholesterol Level

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

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.

Biological interactions of ferromagnetic iron oxide-carbon nanohybrids with alveolar epithelial cells

Iron oxide nanoparticles (IONPs) have been largely investigated in a plethora of biological fields for their interesting physical-chemical properties, which make them suitable for application in cancer therapy, neuroscience, and imaging. Several encouraging results have been reported in these contexts. However, the possible toxic effects of some IONP formulations can limit their applicability. In this work, IONPs were synthesized with a carbon shell (IONP@C), providing enhanced stability both as colloidal dispersion and in the biological environment. We conducted a careful multiparametric evaluation of IONP@C biological interactions in vitro, providing them with an in vivo-like biological identity. Our hybrid nanoformulation showed no cytotoxic effects on a widely employed model of alveolar epithelial cells for a variety of concentrations and exposure times. The IONP@C were efficiently internalized and TEM analysis allowed the protective role of the carbon shell against intracellular degradation to be assessed. Intracellular redistribution of the IONP@C from the lysosomes to the lamellar bodies was also observed after 72 hours.

Engineered nanoparticles enable deep proteomics studies at scale by leveraging tunable nano-bio interactions

SignificanceDeep profiling of the plasma proteome at scale has been a challenge for traditional approaches. We achieve superior performance across the dimensions of precision, depth, and throughput using a panel of surface-functionalized superparamagnetic nanoparticles in comparison to conventional workflows for deep proteomics interrogation. Our automated workflow leverages competitive nanoparticle-protein binding equilibria that quantitatively compress the large dynamic range of proteomes to an accessible scale. Using machine learning, we dissect the contribution of individual physicochemical properties of nanoparticles to the composition of protein coronas. Our results suggest that nanoparticle functionalization can be tailored to protein sets. This work demonstrates the feasibility of deep, precise, unbiased plasma proteomics at a scale compatible with large-scale genomics enabling multiomic studies.

Interaction of serum proteins with SARS-CoV-2 RBD

The outbreak of the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has become a worldwide public health crisis. When the SARS-CoV-2 enters the biological fluids in the human body, different types of biomolecules (in particular proteins) may adsorb on its surface and alter its infection ability. Although great efforts have recently been devoted to the interaction of specific antibodies with the SARS-CoV-2, it still remains largely unknown how the other serum proteins affect the infection of the SARS-CoV-2. In this work, we systematically investigate the interaction of serum proteins with the SARS-CoV-2 RBD by molecular docking and all-atom molecular dynamics simulations. It is found that non-specific immunoglobulins (Ig) indeed cannot effectively bind to the SARS-CoV-2 RBD while human serum albumin (HSA) may have some potential in blocking its infection (to ACE2). More importantly, we find that the RBD can cause significant structural changes in Apolipoprotein E (ApoE), by which SARS-CoV-2 may hijack the metabolic pathway of ApoE to facilitate its cell entry. The present study enhances the understanding of the role of protein corona in the bio-behaviors of SARS-CoV-2, which may aid the more precise and personalized treatment for COVID-19 infection in the clinic.

Surface Functionalization of Graphene-Based Materials: Biological Behavior, Toxicology, and Safe-By-Design Aspects

The increasing exploitation of graphene-based materials (GBMs) is driven by their unique properties and structures, which ignite the imagination of scientists and engineers. At the same time, the very properties that make them so useful for applications lead to growing concerns regarding their potential impacts on human health and the environment. Since GBMs are inert to reaction, various attempts of surface functionalization are made to make them reactive. Herein, surface functionalization of GBMs, including those intentionally designed for specific applications, as well as those unintentionally acquired (e.g., protein corona formation) from the environment and biota, are reviewed through the lenses of nanotoxicity and design of safe materials (safe-by-design). Uptake and toxicity of functionalized GBMs and the underlying mechanisms are discussed and linked with the surface functionalization. Computational tools that can predict the interaction of GBMs behavior with their toxicity are discussed. A concise framing of current knowledge and key features of GBMs to be controlled for safe and sustainable applications are provided for the community.

Protein corona profile of graphene oxide allows detection of glioblastoma multiforme using a simple one-dimensional gel electrophoresis technique: a proof-of-concept study

Glioblastoma multiforme (GBM) is the most aggressive form of gliomas. The development of supplementary approaches for glioblastoma diagnosis, limited to imaging techniques and tissue biopsies so far, is a necessity of clinical relevance. In this context, nanotechnology might afford tools to enable early diagnosis. Upon exposure to biological media, nanoparticles are coated with a layer of proteins, the protein corona (PC), whose composition is individual and personalized. Here we show that the PC of graphene oxide nanosheets has a capacity to detect GBM using a simple one-dimensional gel electrophoresis technique. In a range of molecular weights between 100 and 120 kDa, the personalized PC from GBM patients is completely discernible from that of healthy donors and that of cancer patients affected by pancreatic adenocarcinoma and colorectal cancer. Using tandem mass spectrometry, we found that inter-alpha-trypsin inhibitor (ITI) heavy chain H4 is enriched in the PC of all tested individuals but not in the GBM patients. Overall, if confirmed on a larger cohort series, this approach could be advantageous at the first level of investigation to decide whether to carry out more invasive analyses and/or to follow up patients after surgery and/or pharmacological treatment.

Spiky Gold Nanoparticles for the Photothermal Eradication of Colon Cancer Cells

Colorectal cancer (CRC) is a widespread and lethal disease. Relapses of the disease and metastasis are very common in instances of CRC, so adjuvant therapies have a crucial role in its treatment. Systemic toxic effects and the development of resistance during therapy limit the long-term efficacy of existing adjuvant therapeutic approaches. Consequently, the search for alternative strategies is necessary. Photothermal therapy (PTT) represents an innovative treatment for cancer with great potential. Here, we synthesize branched gold nanoparticles (BGNPs) as attractive agents for the photothermal eradication of colon cancer cells. By controlling the NP growth process, large absorption in the first NIR biological window was obtained. The FBS dispersed BGNPs are stable in physiological-like environments and show an extremely efficient light-to-heat conversion capability when irradiated with an 808-nm laser. Sequential cycles of heating and cooling do not affect the BGNP stability. The uptake of BGNPs in colon cancer cells was confirmed using flow cytometry and confocal microscopy, exploiting their intrinsic optical properties. In dark conditions, BGNPs are fully biocompatible and do not compromise cell viability, while an almost complete eradication of colon cancer cells was observed upon incubation with BGNPs and irradiation with an 808-nm laser source. The PTT treatment is characterized by an extremely rapid onset of action that leads to cell membrane rupture by induced hyperthermia, which is the trigger that promotes cancer cell death.

Protein-assisted scalable mechanochemical exfoliation of few-layer biocompatible graphene nanosheets

A facile method to produce few-layer graphene (FLG) nanosheets is developed using protein-assisted mechanical exfoliation. The predominant shear forces that are generated in a planetary ball mill facilitate the exfoliation of graphene layers from graphite flakes. The process employs a commonly known protein, bovine serum albumin (BSA), which not only acts as an effective exfoliation agent but also provides stability by preventing restacking of the graphene layers. The latter is demonstrated by the excellent long-term dispersibility of exfoliated graphene in an aqueous BSA solution, which exemplifies a common biological medium. The development of such potentially scalable and toxin-free methods is critical for producing cost-effective biocompatible graphene, enabling numerous possible biomedical and biological applications. A methodical study was performed to identify the effect of time and varying concentrations of BSA towards graphene exfoliation. The fabricated product has been characterized using Raman spectroscopy, powder X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The BSA-FLG dispersion was then placed in media containing Astrocyte cells to check for cytotoxicity. It was found that lower concentrations of BSA-FLG dispersion had only minute cytotoxic effects on the Astrocyte cells.

Nano-Bio Interactions in Cancer: From Therapeutics Delivery to Early Detection

Understanding the interactions between nanomaterials and biological systems plays a pivotal role in enhancing the efficacy of nanomedicine and advancing the disease diagnosis. The nanoparticle-protein corona, an active biomolecular layer, is formed around nanoparticles (NPs) upon mixing with biological fluid. The surface layer which consists of rapidly exchanged biomolecules is called the "soft" corona. The inner layer which is more stable and tightly packed is called the "hard" corona. It has been suggested that the NP-protein corona has a decisive effect on the in vivo fate of nanomedicine upon intravenously administration into the mouse. Furthermore, the features of the NP-protein corona make it a powerful platform to enrich low-abundance proteins from serum/plasma for downstream mass-spectrometry (MS)-based proteomics for biomarker discovery and disease diagnosis.Herein, we summarize our recent work on the development of nanomedicine and disease detection from the level of nano-bio interactions between nanoparticles and biological systems. Nanomedicine has made substantial progress over the past two decades. However, the significant enhancement of overall patient survival by nanomedicine remains a challenge due to the lack of a deep understanding of nano-bio interactions in the clinical setting. The pharmacokinetic effect of the protein corona on PEGylated NPs during blood circulation indicated that the adsorbed apolipoproteins could prolong the circulation time of NPs. This mechanistic understanding of the protein corona (active biomolecule) formed around polymeric NPs offered insights into enhancing the efficacy of nanomedicine from the biological interactions point of view. Moreover, we discuss the basic rationale for developing bioresponsive cancer nanomedicine by exploiting the pathophysiological environment around the tumor, typically the pH, reactive oxygen species (ROS), and redox-responsive supramolecular motifs based on synthetic amphiphilic polymers. The protein corona in vivo determines the biological fate of NPs, whereas it opens a new avenue to enrich low abundant proteins in a biospecimen ex vivo to render them "visible" for downstream analytical workflows, such as MS-based proteomics. Blood serum/plasma, due to easy accessibility and great potential to uncover and monitor physiological and pathological changes in health and disease, has remained a major source of detecting protein biomarker candidates. Inspired by the features of the NP-protein corona, a Proteograph platform, which integrates multi-NP-protein coronas with MS for large-scale efficient and deep proteome profiling has been developed. Finally, we conclude this Account with a better understanding of nano-bio interactions to accelerate the nanomedicine translation and how MS-based proteomics can boost our understanding of the corona composition and facilitate the identification of disease biomarkers.

Synergistic Analysis of Protein Corona and Haemoglobin Levels Detects Pancreatic Cancer

Simultaneous detection of multiple analytes from a single biological sample is gaining more attention in the development of more reliable and point-of-care diagnostic devices. We developed a multiplexed strategy that combined outcomes of clinical biomarkers with analysis of the protein corona that forms around graphene oxide sheets upon exposure to patient's plasma. As a paradigmatic case study, we selected pancreatic ductal adenocarcinoma (PDAC), mainly because of the absence of effective detection strategies that resulted in an extremely low five-year survival rate after diagnosis (<10%). Association of protein corona analysis and haemoglobin levels discriminated PDAC patients from healthy volunteers in up to 90% of cases. If further confirmed in larger-cohort studies, this approach may be used in the detection of PDAC.

Disentangling Biomolecular Corona Interactions With Cell Receptors and Implications for Targeting of Nanomedicines

Nanoparticles are promising tools for nanomedicine in a wide array of therapeutic and diagnostic applications. Yet, despite the advances in the biomedical applications of nanomaterials, relatively few nanomedicines made it to the clinics. The formation of the biomolecular corona on the surface of nanoparticles has been known as one of the challenges toward successful targeting of nanomedicines. This adsorbed protein layer can mask targeting moieties and creates a new biological identity that critically affects the subsequent biological interactions of nanomedicines with cells. Extensive studies have been directed toward understanding the characteristics of this layer of biomolecules and its implications for nanomedicine outcomes at cell and organism levels, yet several aspects are still poorly understood. One aspect that still requires further insights is how the biomolecular corona interacts with and is “read” by the cellular machinery. Within this context, this review is focused on the current understanding of the interactions of the biomolecular corona with cell receptors. First, we address the importance and the role of receptors in the uptake of nanoparticles. Second, we discuss the recent advances and techniques in characterizing and identifying biomolecular corona-receptor interactions. Additionally, we present how we can exploit the knowledge of corona-cell receptor interactions to discover novel receptors for targeting of nanocarriers. Finally, we conclude this review with an outlook on possible future perspectives in the field. A better understanding of the first interactions of nanomaterials with cells, and -in particular -the receptors interacting with the biomolecular corona and involved in nanoparticle uptake, will help for the successful design of nanomedicines for targeted delivery.

Graphene: An Antibacterial Agent or a Promoter of Bacterial Proliferation?

Graphene materials (GMs) are being investigated for multiple microbiological applications because of their unique physicochemical characteristics including high electrical conductivity, large specific surface area, and robust mechanical strength. In the last decade, studies on the interaction of GMs with bacterial cells appear conflicting. On one side, GMs have been developed to promote the proliferation of electroactive bacteria on the surface of electrodes in bioelectrochemical systems or to accelerate interspecies electron transfer during anaerobic digestion. On the other side, GMs with antibacterial properties have been synthesized to prevent biofilm formation on membranes for water treatment, on medical equipment, and on tissue engineering scaffolds. In this review, we discuss the mechanisms and factors determining the positive or negative impact of GMs on bacteria. Furthermore, we examine the bacterial growth-promoting and antibacterial applications of GMs and debate their practicability.

Graphene: An Antibacterial Agent or a Promoter of Bacterial Proliferation?

Graphene materials (GMs) are being investigated for multiple microbiological applications because of their unique physicochemical characteristics including high electrical conductivity, large specific surface area, and robust mechanical strength. In the last decade, studies on the interaction of GMs with bacterial cells appear conflicting. On one side, GMs have been developed to promote the proliferation of electroactive bacteria on the surface of electrodes in bioelectrochemical systems or to accelerate interspecies electron transfer during anaerobic digestion. On the other side, GMs with antibacterial properties have been synthesized to prevent biofilm formation on membranes for water treatment, on medical equipment, and on tissue engineering scaffolds. In this review, we discuss the mechanisms and factors determining the positive or negative impact of GMs on bacteria. Furthermore, we examine the bacterial growth-promoting and antibacterial applications of GMs and debate their practicability.

Isobaric Labeling Proteomics Allows a High-Throughput Investigation of Protein Corona Orientation

The formation of the biomolecular corona represents a crucial factor in controlling the biological interactions and trafficking of nanomaterials. In this context, the availability of key epitopes exposed on the surface of the corona, and able to engage the biological machinery, is important to define the biological fate of the material. While the full biomolecular corona composition can be investigated by conventional bottom-up proteomics, the assessment of the spatial orientation of proteins in the corona in a high-throughput fashion is still challenging. In this work, we show that labeling corona proteins with isobaric tags in their native conditions and analyzing the MS/MS spectra of tryptic peptides allow an easy and high-throughput assessment of the inner/outer orientation of the corresponding proteins in the original corona. We put our results in the context of what is currently known of the protein corona of graphene-based nanomaterials. Our conclusions are in line with previous data and were confirmed by in silico calculations.

2D materials in electrochemical sensors for in vitro or in vivo use

Individual cells and cell populations are at the present time investigated with a myriad of analytical tools. While most of them are commercially available, some of these analytical tools are just emerging from research laboratories and are in the developmental phase. Electrochemical sensors which allow the monitoring of low molecular weight compounds released (and / or uptaken) by cells are among these emerging tools. Such sensors are increasingly built using 2D materials (e.g. graphene-based materials, transition metal dichalcogenides, etc.) with the aim of conferring better analytical performances to these devices. The present work critically reviews studies published during the last 10 years describing electrochemical sensors made with 2D materials and exploited to monitor small compounds (e.g. H₂O₂, ·NO, glucose, etc.) in living biological systems. It also discusses the very few 2D material-based electrochemical sensors which are wearable or usable in vivo. Finally, the present work includes a specific section about 2D material biocompatibility, a fundamental requirement for 2D material-based sensor applications in vitro and in vivo. As such, the review provides a critical view on the state of the art of electrochemical sensors made with 2D materials and used at cellular level and it evaluates the possibility that such sensors will be used on / in the human body on a wider scale.

Protein Corona and Immune Responses of Borophene: A Comparison of Nanosheet-Plasma Interface with Graphene and Phosphorene

Borophene has emerged as a type of two-dimensional monoelemental nanomaterials with excellent drug loading capacity and photothermal properties. Here, we demonstrated the adsorption of plasma proteins onto borophene nanosheets (B NSs) and the promoted immune responses of macrophage by the B NS-corona complex. We discovered that plasma proteins changed the surface identities of B NSs. Using proteomics analysis, 46.5% of the proteins bound to B NSs (94 plasma proteins) were immune-relevant proteins. Uptake of B NSs by phagolysosomes was observed, and the plasma corona promoted the uptake. In comparison with graphene and phosphorene, we found that 32 plasma proteins appeared on all of the three nanosheets. The proportion of immune-relevant proteins in graphene-corona and phosphorene-corona was 41.3% and 75.6%, respectively. The components of the adsorbed immune-relevant proteins show diversity, which influence the immune responses of these nanosheets. Phosphorene-corona showed the most remarkable immunoregulatory behavior in these nanosheets. For the first time, we compared the highly complex protein corona at the nanosheet-plasma interface of three key 2D monoelemental nanosheets. Our study helps to understand the interaction between borophene and biological systems and provides a theoretical basis for the development and application of borophene in the biomedical field.

Personalized Graphene Oxide-Protein Corona in the Human Plasma of Pancreatic Cancer Patients

The protein corona (PC) that forms around nanomaterials upon exposure to human biofluids (e.g., serum, plasma, cerebral spinal fluid etc.) is personalized, i.e., it depends on alterations of the human proteome as those occurring in several cancer types. This may relevant for early cancer detection when changes in concentration of typical biomarkers are often too low to be detected by blood tests. Among nanomaterials under development for in vitro diagnostic (IVD) testing, Graphene Oxide (GO) is regarded as one of the most promising ones due to its intrinsic properties and peculiar behavior in biological environments. While recent studies have explored the binding of single proteins to GO nanoflakes, unexplored variables (e.g., GO lateral size and protein concentration) leading to formation of GO-PC in human plasma (HP) have only marginally addressed so far. In this work, we studied the PC that forms around GO nanoflakes of different lateral sizes (100, 300, and 750 nm) upon exposure to HP at several dilution factors which extend over three orders of magnitude from 1 (i.e., undiluted HP) to 10³. HP was collected from 20 subjects, half of them being healthy donors and half of them diagnosed with pancreatic ductal adenocarcinoma (PDAC) a lethal malignancy with poor prognosis and very low 5-year survival rate after diagnosis. By dynamic light scattering (DLS), electrophoretic light scattering (ELS), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and nano liquid chromatography tandem mass spectrometry (nano-LC MS/MS) experiments we show that the lateral size of GO has a minor impact, if any, on PC composition. On the other side, protein concentration strongly affects PC of GO nanoflakes. In particular, we were able to set dilution factor of HP in a way that maximizes the personalization of PC, i.e., the alteration in the protein profile of GO nanoflakes between cancer vs. non-cancer patients. We believe that this study shall contribute to a deeper understanding of the interactions among GO and HP, thus paving the way for the development of IVD tools to be used at every step of the patient pathway, from prognosis, screening, diagnosis to monitoring the progression of disease.

Graphene Surfaces Interaction with Proteins, Bacteria, Mammalian Cells, and Blood Constituents: The Impact of Graphene Platelet Oxidation and Thickness

Graphene-based materials (GBMs) have been increasingly explored for biomedical applications. However, interaction between GBMs-integrating surfaces and bacteria, mammalian cells, and blood components, that is, the major biological systems in our body, is still poorly understood. In this study, we systematically explore the features of GBMs that most strongly impact the interactions of GBMs films with plasma proteins and biological systems. Films produced by vacuum filtration of GBMs with different oxidation degree and thickness depict different surface features: graphene oxide (GO) and few-layer GO (FLGO) films are more oxidized, smoother, and hydrophilic, while reduced GO (rGO) and few-layer graphene (FLG) are less or nonoxidized, rougher, and more hydrophobic. All films promote glutathione oxidation, although in a lower extent by rGO, indicating their potential to induce oxidative stress in biological systems. Human plasma proteins, which mediate most of the biological interactions, adsorb less to oxidized films than to rGO and FLG. Similarly, clinically relevant bacteria, Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, adhere less to GO and FLGO films, while rGO and FLG favor bacterial adhesion and viability. Surface features caused by the oxidation degree and thickness of the GBMs powders within the films have less influence toward human foreskin fibroblasts; all materials allow cell adhesion, proliferation and viability up to 14 days, despite less on rGO surfaces. Blood cells adhere to all films, with higher numbers in less or nonoxidized surfaces, despite none having caused hemolysis (<5%). Unlike thickness, oxidation degree of GBMs platelets strongly impact surface morphology/topography/chemistry of the films, consequently affecting protein adsorption and thus bacteria, fibroblasts and blood cells response. Overall, this study provides useful guidelines regarding the choice of the GBMs to use in the development of surfaces for an envisioned application. Oxidized materials appear as the most promising for biomedical applications that require low bacterial adhesion without being cytotoxic to mammalian cells.

Machine learning predicts the functional composition of the protein corona and the cellular recognition of nanoparticles

The protein corona affects the clinical applications, organ targeting, and safety assessment of nanomaterials, and prediction of the protein corona would be valuable for the design of ideal nanomaterials. However, no methods to predict the protein corona are available. Overcoming the numerous quantitative and qualitative factors influencing corona formation, the present work builds models that precisely predict the functional composition of the protein corona and the cell recognition of nanoparticles (NPs) integrating machine learning and meta-analysis. This workflow provides an effective method to predict the functional composition of the protein corona that determines cell recognition to guide the synthesis and applications of NPs.

Protein corona formation is critical for the design of ideal and safe nanoparticles (NPs) for nanomedicine, biosensing, organ targeting, and other applications, but methods to quantitatively predict the formation of the protein corona, especially for functional compositions, remain unavailable. The traditional linear regression model performs poorly for the protein corona, as measured by R² (less than 0.40). Here, the performance with R² over 0.75 in the prediction of the protein corona was achieved by integrating a machine learning model and meta-analysis. NPs without modification and surface modification were identified as the two most important factors determining protein corona formation. According to experimental verification, the functional protein compositions (e.g., immune proteins, complement proteins, and apolipoproteins) in complex coronas were precisely predicted with good R² (most over 0.80). Moreover, the method successfully predicted the cellular recognition (e.g., cellular uptake by macrophages and cytokine release) mediated by functional corona proteins. This workflow provides a method to accurately and quantitatively predict the functional composition of the protein corona that determines cellular recognition and nanotoxicity to guide the synthesis and applications of a wide range of NPs by overcoming limitations and uncertainty.

Hemocompatibility of Carbon Nanostructures

Carbon nanostructures (CNs), such as carbon nanotubes, fullerenes, carbon dots, nanodiamonds as well as graphene and its derivatives present a tremendous potential for various biomedical applications, ranging from sensing to drug delivery and gene therapy, biomedical imaging and tissue engineering. Since most of these applications encompass blood contact or intravenous injection, hemocompatibility is a critical aspect that must be carefully considered to take advantage of CN exceptional characteristics while allowing their safe use. This review discusses the hemocompatibility of different classes of CNs with the purpose of providing biomaterial scientists with a comprehensive vision of the interactions between CNs and blood components. The various complex mechanisms involved in blood compatibility, including coagulation, hemolysis, as well as the activation of complement, platelets, and leukocytes will be considered. Special attention will be paid to the role of CN size, structure, and surface properties in the formation of the protein corona and in the processes that drive blood response. The aim of this review is to emphasize the importance of hemocompatibility for CNs intended for biomedical applications and to provide some valuable insights for the development of new generation particles with improved performance and safety in the physiological environment.

Engineering biomimetic graphene nanodecoys camouflaged with the EGFR/HEK293 cell membrane for targeted capture of drug leads

A novel cell membrane camouflaged graphene-based nanodecoy with targeting properties was first established for drug lead screening.

Mitochondria-targeted TPP-MoS2 with dual enzyme activity provides efficient neuroprotection through M1/M2 microglial polarization in an Alzheimer's disease model

Alzheimer's disease (AD) is one of the most common age-associated brain diseases and is induced by the accumulation of amyloid beta (Aβ) and oxidative stress. Many studies have focused on eliminating Aβ by nanoparticle affinity; however, nanoparticles are taken up mainly by microglia rather than neurons, leading poor control of AD. Herein, mitochondria-targeted nanozymes known as (3-carboxypropyl)triphenyl-phosphonium bromide-conjugated 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000]-functionalized molybdenum disulfide quantum dots (TPP-MoS₂ QDs) were designed. TPP-MoS₂ QDs mitigate Aβ aggregate-mediated neurotoxicity and eliminate Aβ aggregates in AD mice by switching microglia from the proinflammatory M1 phenotype to the anti-inflammatory M2 phenotype. TPP-MoS₂ QDs cross the blood-brain barrier, escape from lysosomes, target mitochondria and exhibit the comprehensive activity of a bifunctional nanozyme, thus preventing spontaneous neuroinflammation by regulating the proinflammatory substances interleukin-1β, interleukin-6 and tumor necrosis factors as well as the anti-inflammatory substance transforming growth factor-β. In contrast to the low efficacy of eliminating Aβ by nanoparticle affinity, the present study provides a new pathway to mitigate AD pathology through mitochondria-targeted nanozymes and M1/M2 microglial polarization.

Multi-functionalised graphene nanoflakes as tumour-targeting theranostic drug-delivery vehicles

Graphene nanoflakes (GNFs) consist of a graphene sheet approximately 30 nm in diameter with a pristine aromatic system and an edge terminated with carboxylic acid groups. Their high water solubility and relative ease of functionalisation using carboxylate chemistry means that GNFs are potential scaffolds for the synthesis of theranostic agents. In this work, GNFs were multi-functionalised with derivatives of (i) a peptide-based Glu-NH-C(O)-NH-Lys ligand that binds prostate-specific membrane antigen (PSMA), (ii) a potent anti-mitotic drug (R)-ispinesib, (iii) the chelate desferrioxamine B (DFO), and (iv) an albumin-binding tag reported to extend pharmacokinetic half-life in vivo. Subsequent 68Ga radiochemistry and experiments in vitro and in vivo were used to evaluate the performance of GNFs in theranostic drug design. Efficient 68Ga-radiolabelling was achieved and the particle-loading of (R)-ispinesib and Glu-NH-C(O)-NH-Lys was confirmed using cellular assays. Using dose-response curves and FACS analysis it was shown that GNFs loaded with (R)-ispinesib inhibited the kinesin spindle protein (KSP) and induced G2/M-phase cell cycle arrest. Cellular uptake and blocking experiments demonstrated that GNFs functionalised with the Glu-NH-C(O)-NH-Lys ligand showed specificity toward PSMA expressing cells (LNCaP). The distribution profile and excretion rates of 68Ga-radiolabelled GNFs in athymic nude mice was evaluated using time-activity curves derived from dynamic positron-emission tomography (PET). Image analysis indicated that GNFs have low accumulation and retention in background tissue, with rapid renal clearance. In summary, our study shows that GNFs are suitable candidates for use in theranostic drug design.

Tailoring the component of protein corona via simple chemistry

Control over the protein corona of nanomaterials allows them to function better. Here, by taking graphene/gold as examples, we comprehensively assessed the association of surface properties with the protein corona. As revealed by in vitro measurements and computations, the interaction between graphene/gold and HSA/IgE was inversely correlated with the hydroxyl group availability, whereas the interaction between that and ApoE was comparatively less relevant. Molecular simulations revealed that the number and the distribution of surface hydroxyl groups could regulate the manner in which nanomaterials interact with proteins. Moreover, we validated that ApoE pre-adsorption before injection enhances the blood circulation of nanomaterials relative to their pristine and IgE-coated counterparts. This benefit can be attributed to the invulnerability of the complementary system provided by ApoE, whose encasement does not increase cytotoxicity. Overall, this study offers a robust yet simple way to create protein corona enriched in dysopsonins to realize better delivery efficacy.

The interaction between proteins and nanomaterials is complex and of interest for controlling nanoparticle fate. Here, using experimental and computational methods, the authors report on the effect of hydroxyl groups on protein interaction and how they can be used to enhance circulation times.

Adsorption of Human Serum Albumin on Graphene Oxide: Implications for Protein Corona Formation and Conformation

The influence of solution chemistry on the adsorption of human serum albumin (HSA) proteins on graphene oxide (GO) was investigated through batch adsorption experiments and the use of a quartz crystal microbalance with dissipation (QCM-D). The conformation of HSA layers on GO was also examined with the QCM-D. Our results show that an increase in ionic strength under neutral pH conditions resulted in stronger binding between HSA and GO, as well as more compact HSA layers on GO, emphasizing the key role of electrostatic interactions in controlling HSA-GO interactions. Calcium ions also facilitated HSA adsorption likely through charge neutralization and bridging effect. At physiological ionic strength conditions (150 mM), maximum HSA adsorption was observed at the isoelectric point of HSA (4.7). Under acidic conditions, the adsorption of HSA on GO led to the formation of protein layers with a high degree of fluidity due to the extended conformation of HSA. Finally, the attachment of GO to a supported lipid bilayer that was composed of zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine, a model for cell membranes, was reduced in the presence of protein coronas. This reduction in GO attachment was influenced by the conformation of the protein coronas on GO.

Graphene-Based Nanomaterials: From Production to Integration With Modern Tools in Neuroscience

Graphene, a two-dimensional carbon crystal, has emerged as a promising material for sensing and modulating neuronal activity in vitro and in vivo. In this review, we provide a primer for how manufacturing processes to produce graphene and graphene oxide result in materials properties that may be tailored for a variety of applications. We further discuss how graphene may be composited with other bio-compatible materials of interest to make novel hybrid complexes with desired characteristics for bio-interfacing. We then highlight graphene's ever-widen utility and unique properties that may in the future be multiplexed for cross-modal modulation or interrogation of neuronal network. As the biological effects of graphene are still an area of active investigation, we discuss recent development, with special focus on how surface coatings and surface properties of graphene are relevant to its biological effects. We discuss studies conducted in both non-murine and murine systems, and emphasize the preclinical aspect of graphene's potential without undermining its tangible clinical implementation.

Graphene-based nanomaterials: the promising active agents for antibiotics-independent antibacterial applications

Graphene-based nanomaterials, such as graphene oxide (GO) and reduced graphene oxide (rGO), have shown great potentials in drug delivery and photodynamic/photothermal therapy due to their featured structure and physicochemical properties. In recent years, their antibacterial potentials have also been exploited. The commonly recognized antibacterial mechanisms include sharp edge-mediated cutting effect, oxidative stress and cell entrapment. This antibacterial activity is very important for human health. As we know, infection with the pathogenic bacteria, especially the drug-resistant ones, is a great threat to human lives. Thus, the development of the antibiotics-independent and drug-free antibacterial agents is of great importance and significance. Graphene-based nanomaterials are a kind of such antibacterial agents. An insight into their properties and antibacterial mechanisms is necessary before they are developed into real products. Herein, we provide a comprehensive understanding of the antibacterial application of graphene-based nanomaterials via summarizing their antibacterial activities against some typical microbial species and discussing their unique mechanisms. In addition, the side-effects and problems in using these nanomaterials are also discussed.

Transport of a graphene nanosheet sandwiched inside cell membranes

The transport of nanoparticles at bio-nano interfaces is essential for many cellular responses and biomedical applications. How two-dimensional nanomaterials, such as graphene and transition-metal dichalcogenides, diffuse along the cell membrane is, however, unknown, posing an urgent and important issue to promote their applications in the biomedical area. Here, we show that the transport of graphene oxides (GOs) sandwiched inside cell membranes varies from Brownian to Lévy and even directional dynamics. Specifically, experiments evidence sandwiched graphene-cell membrane superstructures in different cells. Combined simulations and analysis identify a sandwiched GO-induced pore in cell membrane leaflets, spanning unstable, metastable, and stable states. An analytical model that rationalizes the regimes of these membrane-pore states fits simulations quantitatively, resulting in a mechanistic interpretation of the emergence of Lévy and directional dynamics. We finally demonstrate the applicability of sandwiched GOs in enhanced efficiency of membrane-specific drug delivery. Our findings inform approaches to programming intramembrane transport of two-dimensional nanomaterials toward advantageous biomedical applications.

Protease Degradation of Protein Coronas and Its Impact on Cancer Cells and Drug Payload Release

The effect of matrix metalloproteinases (MMPs) on preformed protein coronas around spherical gold nanoparticles (AuNPs) was studied. Protein coronas of different compositions (human serum, human serum albumin, and collagen IV) were formed around AuNPs and characterized. The protease MMP-9 had different effects on the corona depending on the corona composition, resulting in different changes to the corona hydrodynamic diameter ( D_H). When incubated with PANC-1 cells, the corona showed evidence of both increases as well as decreases in D_H. Varying the composition of the corona influenced the MMP-9 activity. Furthermore, the corona was influenced not only by the protease activity of the MMP-9 but also by its ability to exchange with proteins in the preformed corona. This exchange could also occur with proteins in the media. Thus, the net effect of the MMP-9 was a combination of the MMP-9 protease activity and also exchange. Time scales for the exchange varied depending on the nature that make up the protein corona (weakly vs strongly bound corona proteins). Mass spectrometry was used to probe the protein corona composition and supported the exchange and degradation model. Together, these results indicate that the mechanism of protease activity on AuNP coronas involves both rearrangement and exchange, followed by degradation.

Digestive Enzyme Corona Formed in the Gastrointestinal Tract and Its Impact on Epithelial Cell Uptake of Nanoparticles

The fate of intravenously injected nanoparticles (NPs) is significantly affected by nano-protein interaction and corona formation. However, such an interaction between NPs and digestive enzymes occurring in the gastrointestinal tract (GIT) and its impacts on epithelial cell uptake are little known. We synthesized the poly(3-hydroxybutyrate- co-3-hydroxyhexanoate)-based cationic NPs (CNPs) and investigated the CNP-digestive enzyme interaction and its effect on the cellular uptake. The formation of enzyme corona was confirmed by size/zeta potential analysis, morphology, sodium dodecyl sulfate polyacrylamide gel electrophoresis, and enzyme quantification. The cellular uptake of CNPs by Caco-2 cells was significantly reduced upon the formation of enzyme corona. Our findings demonstrate the digestive enzyme corona formation and its inhibited effect on the epithelial cell uptake of CNPs for the first time. Understanding the enzyme corona could offer a new insight into the fate of nanomedicines in the GIT, and this understanding would be highly beneficial for guiding future nanomedicine designs.

Graphene oxide touches blood: in vivo interactions of bio-coronated 2D materials

Graphene oxide is the hot topic in biomedical and pharmaceutical research of the current decade. However, its complex interactions with human blood components complicate the transition from the promising in vitro results to clinical settings. Even though graphene oxide is made with the same atoms as our organs, tissues and cells, its bi-dimensional nature causes unique interactions with blood proteins and biological membranes and can lead to severe effects like thrombogenicity and immune cell activation. In this review, we will describe the journey of graphene oxide after injection into the bloodstream, from the initial interactions with plasma proteins to the formation of the "biomolecular corona", and biodistribution. We will consider the link between the chemical properties of graphene oxide (and its functionalized/reduced derivatives), protein binding and in vivo response. We will also summarize data on biodistribution and toxicity in view of the current knowledge of the influence of the biomolecular corona on these processes. Our aim is to shed light on the unsolved problems regarding the graphene oxide corona to build the groundwork for the future development of drug delivery technology.