Copper doping enhanced the oxidative stress-mediated cytotoxicity of TiO2 nanoparticles in A549 cells

Research advance of occupational exposure risks and toxic effects of semiconductor nanomaterials

In recent years, semiconductor nanomaterials, as one of the most promising and applied classes of engineered nanomaterials, have been widely used in industries such as photovoltaics, electronic devices, and biomedicine. However, occupational exposure is unavoidable during the production, use, and disposal stages of products containing these materials, thus posing potential health risks to workers. The intricacies of the work environment present challenges in obtaining comprehensive data on such exposure. Consequently, there remains a significant gap in understanding the exposure risks and toxic effects associated with semiconductor nanomaterials. This paper provides an overview of the current classification and applications of typical semiconductor nanomaterials. It also delves into the existing state of occupational exposure, methodologies for exposure assessment, and prevailing occupational exposure limits. Furthermore, relevant epidemiological studies are examined. Subsequently, the review scrutinizes the toxicity of semiconductor nanomaterials concerning target organ toxicity, toxicity mechanisms, and influencing factors. The aim of this review is to lay the groundwork for enhancing the assessment of occupational exposure to semiconductor nanomaterials, optimizing occupational exposure limits, and promoting environmentally sustainable development practices in this domain.

Spectrophotometrically, Spectroscopically, Microscopically and Thermogravimetrically Optimized TiO2 and ZnO Nanoparticles and their Bactericidal, Antioxidant and Cytotoxic Potential: A Novel Comparative Approach

Current study was aimed to determine the antibacterial, antioxidant and cytotoxic potential of Titanium dioxide nanoparticles (TiO2NPs) and Zinc oxide nanoparticles (ZnONPs). Nanoparticles were characterized by UV-Vis spectrophotometry, particle size analyzer (PSA), fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The Minimum inhibitory concentration (MIC) was determined by standard agar dilution method. Antibacterial potential of nanoparticles was analyzed by standard disc diffusion method against bacterial strains including Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia. Different concentrations of NPs (0.2, 0.4, 0.6, 0.8, 1.0, 1.2 and 1.4 mg/mL) were incorporated to evaluate the antimicrobial activity. Antioxidant activity and cytotoxicity of these NPs was analyzed by DPPH method and brine shrimp cytotoxicity assay, respectively. The MIC of TiO2NPs against E. coli, P. aeruginosa and K. pneumoniae was 0.04, 0.08 and 0.07 mg/mL respectively while the MIC of ZnONPs against the above strains was 0.01, 0.015 and 0.01 mg/mL. The maximum zone of inhibition was observed for K. pneumoniae i.e., 20mm and 25mm against TiO2 and ZnO NPs respectively, at 1.4 mg/mL concentration of NPs. The susceptibility of NPs against bacterial strains was evaluated in the following order: K. pneumoniae > P. aeruginosa > E. coli. The antioxidant activity of nanoparticles increased by increasing the concentration of NPs while cytotoxic analysis exhibited non-toxic effect of ZnO NPs while TiO2 had toxic effects on 1.2 and 1.4 mg/mL concentrations. Results revealed that ZnO NPs have more antibacterial and negligible cytotoxic potential in contrast to TiO2 NPs.

An updated overview of some factors that influence the biological effects of nanoparticles

Nanoparticles (NPs) can be extremely effective in the early diagnosis and treatment of cancer due to their properties. The nanotechnology industry is developing rapidly. The number of multifunctional NPs has increased in the market and hundreds of NPs are in various stages of preclinical and clinical development. Thus, the mechanism underlying the effects of NPs on biological systems has received much attention. After NPs enter the body, they interact with plasma proteins, tumour cell receptors, and small biological molecules. This interaction is closely related to the size, shape, chemical composition and surface modification properties of NPs. In this review, the effects of the size, shape, chemical composition and surface modification of NPs on the biological effects of NPs were summarised, including the mechanism through which NPs enter cells, the resulting oxidative stress response, and the interaction with proteins. This review of the biological effects of NPs can not only provide theoretical support for the preparation of safer and more efficient NPs but also lay the foundation for their clinical application.

Development of Phytochemical Delivery Systems by Nano-Suspension and Nano-Emulsion Techniques

The awareness of the existence of plant bioactive compounds, namely, phytochemicals (PHYs), with health properties is progressively expanding. Therefore, their massive introduction in the normal diet and in food supplements and their use as natural therapeutics to treat several diseases are increasingly emphasized by several sectors. In particular, most PHYs possessing antifungal, antiviral, anti-inflammatory, antibacterial, antiulcer, anti-cholesterol, hypoglycemic, immunomodulatory, and antioxidant properties have been isolated from plants. Additionally, their secondary modification with new functionalities to further improve their intrinsic beneficial effects has been extensively investigated. Unfortunately, although the idea of exploiting PHYs as therapeutics is amazing, its realization is far from simple, and the possibility of employing them as efficient clinically administrable drugs is almost utopic. Most PHYs are insoluble in water, and, especially when introduced orally, they hardly manage to pass through physiological barriers and scarcely reach the site of action in therapeutic concentrations. Their degradation by enzymatic and microbial digestion, as well as their rapid metabolism and excretion, strongly limits their in vivo activity. To overcome these drawbacks, several nanotechnological approaches have been used, and many nanosized PHY-loaded delivery systems have been developed. This paper, by reporting various case studies, reviews the foremost nanosuspension- and nanoemulsion-based techniques developed for formulating the most relevant PHYs into more bioavailable nanoparticles (NPs) that are suitable or promising for clinical application, mainly by oral administration. In addition, the acute and chronic toxic effects due to exposure to NPs reported so far, the possible nanotoxicity that could result from their massive employment, and ongoing actions to improve knowledge in this field are discussed. The state of the art concerning the actual clinical application of both PHYs and the nanotechnologically engineered PHYs is also reviewed.

MRC-5 Human Lung Fibroblasts Alleviate the Genotoxic Effect of Fe-N Co-Doped Titanium Dioxide Nanoparticles through an OGG1/2-Dependent Reparatory Mechanism

The current study was focused on the potential of pure P25 TiO2 nanoparticles (NPs) and Fe(1%)-N co-doped P25 TiO2 NPs to induce cyto- and genotoxic effects in MRC-5 human pulmonary fibroblasts. The oxidative lesions of P25 NPs were reflected in the amount of 8-hydroxydeoxyguanosine accumulated in DNA and the lysosomal damage produced, but iron-doping partially suppressed these effects. However, neither P25 nor Fe(1%)-N co-doped P25 NPs had such a serious effect of inducing DNA fragmentation or activating apoptosis signaling. Moreover, oxo-guanine glycosylase 1/2, a key enzyme of the base excision repair mechanism, was overexpressed in response to the oxidative DNA deterioration induced by P25 and P25-Fe(1%)-N NPs.

The impact of Zn doping on CdTe quantum dots-protein corona formation and the subsequent toxicity at the molecular and cellular level

Understanding the formation of protein corona (PC) is of vital importance for exploring the toxicity of nanoparticles and promoting their safe applications. In this study, CdTe QDs doping with 0, 1%, 5% and 10% Zn were synthesized using one-pot hydrothermal methods. Afterwards, this study explored and compared the formation of pure and Zn doped-QDs PC as well as the subsequent molecular and cellular toxicity. Result found that Zn doping regulated the toxicity of Cd-QDs by controlling their ability to adsorb serum proteins. The adsorption to Cd-QDs induced the dispersion, unfolding, secondary structural changes and the activity loss of bovine serum albumin (BSA). Among the synthesized Cd-QDs, 10%Zn-QDs exhibited the highest fluorescence quantum yield and lowest molecular toxicity. The formations of pure QDs and 10%Zn-QDs with BSA corona are majorly driven by different forces with different patterns. The regulation of BSA on the cytotoxicity differences of pure QDs and 10%Zn-QDs was similar with fetal bovine serum, proving the significant contribution of BSA to the cytotoxicity of Cd-QDs PC. Compared with pure QDs PC, the higher cytotoxicity and oxidative stress level of 10%Zn-QDs PC were correlated with higher intracellular [Cd²⁺]. Both larger amount of BSA adsorption and higher level of intracellular reactive oxygen species could accelerate the dissolution rates of 10%Zn-QDs and thus result in higher intracellular [Cd²⁺].

Evaluating the Use of TiO2 Nanoparticles for Toxicity Testing in Pulmonary A549 Cells

Purpose

Titanium dioxide nanoparticles, 25 nm in size of crystallites (TiO₂ P25), are among the most produced nanomaterials worldwide. The broad use of TiO₂ P25 in material science has implied a request to evaluate their biological effects, especially in the lungs. Hence, the pulmonary A549 cell line has been used to estimate the effects of TiO₂ P25. However, the reports have provided dissimilar results on caused toxicity. Surprisingly, the physicochemical factors influencing TiO₂ P25 action in biological models have not been evaluated in most reports. Thus, the objective of the present study is to characterize the preparation of TiO₂ P25 for biological testing in A549 cells and to evaluate their biological effects.

Methods

We determined the size and crystallinity of TiO₂ P25. We used four techniques for TiO₂ P25 dispersion. We estimated the colloid stability of TiO₂ P25 in distilled water, isotonic NaCl solution, and cell culture medium. We applied the optimal dispersion conditions for testing the biological effects of TiO₂ P25 (0–100 µg.mL⁻¹) in A549 cells using biochemical assays (dehydrogenase activity, glutathione levels) and microscopy.

Results

We found that the use of fetal bovine serum in culture medium is essential to maintain sufficient colloid stability of dispersed TiO₂ P25. Under these conditions, TiO₂ P25 were unable to induce a significant impairment of A549 cells according to the results of biochemical and microscopy evaluations. When the defined parameters for the use of TiO₂ P25 in A549 cells were met, similar results on the biological effects of TiO₂ P25 were obtained in two independent cell laboratories.

Conclusion

We optimized the experimental conditions of TiO₂ P25 preparation for toxicity testing in A549 cells. The results presented here on TiO₂ P25-induced cellular effects are reproducible. Therefore, our results can be helpful for other researchers using TiO₂ P25 as a reference material.

N-Doped Graphene Quantum Dots/Titanium Dioxide Nanocomposites: A Study of ROS-Forming Mechanisms, Cytotoxicity and Photodynamic Therapy

Titanium dioxide nanoparticles (TiO2 NPs) have been proven to be potential candidates in cancer therapy, particularly photodynamic therapy (PDT). However, the application of TiO2 NPs is limited due to the fast recombination rate of the electron (e−)/hole (h+) pairs attributed to their broader bandgap energy. Thus, surface modification has been explored to shift the absorption edge to a longer wavelength with lower e−/h+ recombination rates, thereby allowing penetration into deep-seated tumors. In this study, TiO2 NPs and N-doped graphene quantum dots (QDs)/titanium dioxide nanocomposites (N-GQDs/TiO2 NCs) were synthesized via microwave-assisted synthesis and the two-pot hydrothermal method, respectively. The synthesized anatase TiO2 NPs were self-doped TiO2 (Ti3+ ions), have a small crystallite size (12.2 nm) and low bandgap energy (2.93 eV). As for the N-GQDs/TiO2 NCs, the shift to a bandgap energy of 1.53 eV was prominent as the titanium (IV) tetraisopropoxide (TTIP) loading increased, while maintaining the anatase tetragonal crystal structure with a crystallite size of 11.2 nm. Besides, the cytotoxicity assay showed that the safe concentrations of the nanomaterials were from 0.01 to 0.5 mg mL−1. Upon the photo-activation of N-GQDs/TiO2 NCs with near-infrared (NIR) light, the nanocomposites generated reactive oxygen species (ROS), mainly singlet oxygen (1O2), which caused more significant cell death in MDA-MB-231 (an epithelial, human breast cancer cells) than in HS27 (human foreskin fibroblast). An increase in the N-GQDs/TiO2 NCs concentrations elevates ROS levels, which triggered mitochondria-associated apoptotic cell death in MDA-MB-231 cells. As such, titanium dioxide-based nanocomposite upon photoactivation has a good potential as a photosensitizer in PDT for breast cancer treatment.

Assessing the potential biological activities of TiO2 and Cu, Ni and Cr doped TiO2 nanoparticles

Nanoparticles are like magic bullets and nanomaterials exhibit appealing properties. Their size and morphology can be switched by dopants for certain biological activities. Nanoparticles in combination with certain drugs enhance the antibiotic effects and may be valuable in combating bacterial resistance. The antimicrobial potency of nanoparticles depends upon their ability to bind to the surface of microbial cell membranes resulting in modulation of basic cell functions such as respiration. We report herein the antibacterial, antifungal and antioxidant activities of pure TiO₂ and TiO₂ doped with 4% Cu, Ni and Cr. The performance of pure and doped nanoparticles has been compared with reference compounds. A comparison of the antifungal activities of the samples doped with TiO₂ reveals that Cu-TiO₂ exhibits improved performance against A. fumigatus but lower antifungal activity against Mucor sp. and F. solani. Cu-TiO₂ and Ni-TiO₂ showed good antibacterial action against B. bronchiseptica, while Cr-TiO₂ nanoparticles displayed better activity against S. typhimurium as compared to pure TiO₂. Moreover, pristine TiO₂ and Ni-TiO₂ nanoparticles were found to demonstrate maximum total antioxidant capacity.

Copper ferrite nanoparticles induced cytotoxicity and oxidative stress in Channel catfish ovary cells

Nanomaterials are the sixth most emerging contaminants that are entering into aquatic habitat posing a risk to the inhabiting organisms. Nanoparticles of copper ferrite have been extensively used in biomedical applications. However, very limited studies are available on the cytotoxicity evaluation of copper ferrite nanoparticles (CuFe₂O₄NPs) on different cell lines. The current work investigates on the cytotoxicity, oxidative stress and morphological variations triggered by CuFe₂O₄NPs in Channel catfish ovary (CCO) cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT), neutral red uptake (NRU), lipid peroxidation (LPO), catalase (CAT), reduced glutathione (GSH), glutathione sulfotransferase (GST) and glutathione peroxidase (GPX) assays after 24 h of treatment. Dose dependent decline in cell survival was noticed in MTT and NRU assays. A significant increase in LPO, GST and GPX was observed in CCO cells exposed to CuFe₂O₄NPs after 24 h of treatment. However, the CAT and GSH levels in CCO cells exposed to CuFe₂O₄NPs decreased significantly after 24 h. The CCO cells exposed to 10 μg/mL concentration of CuFe₂O₄NPs for 24 h showed remarkable changes in their morphology. Further, the study also describes the detailed mechanism of toxicity of CuFe₂O₄NPs in other model cell lines to probe the risk of inhabiting organisms.

Application of quasi-SMILES to the model of gold-nanoparticles uptake in A549 cells

Cell death is critical to human health and is associated with a variety of medical conditions. Therefore, new controllers of cell death are needed for the treatment of diverse diseases. In particular, nanoparticles (NP) are now regularly used in various applications, including a variety of products and medicines. Gold nanoparticles (GNPs) are widely used in the medical field against A549 lung carcinoma cells. The present study is devoted to developing computational models of the cellular uptake potentials by A549 cells of gold nanoparticles (GNPs) under various conditions. Simplified molecular input-line entry system (SMILES) is an efficient tool to represent the molecular structure by a sequence of symbols. Quasi-SMILES represents an extended version of SMILES where symbols to denote physicochemical and/or biochemical conditions are added. In other words, the quasi-SMILES represents a biochemical (medical) phenomenon related to the whole matter (not only molecular structure). We developed models for the cellular utpake potential of gold nanoparticles (GNPs) in A549 [10-11 g Au/Cell] under various conditions based on quasi-SMILES using the Monte Carlo method. The statistical quality of these models is quite good.

Safe Nanoparticles: Are We There Yet?

The field of nanotechnology has grown over the last two decades and made the transition from the benchtop to applied technologies. Nanoscale-sized particles, or nanoparticles, have emerged as promising tools with broad applications in drug delivery, diagnostics, cosmetics and several other biological and non-biological areas. These advances lead to questions about nanoparticle safety. Despite considerable efforts to understand the toxicity and safety of these nanoparticles, many of these questions are not yet fully answered. Nevertheless, these efforts have identified several approaches to minimize and prevent nanoparticle toxicity to promote safer nanotechnology. This review summarizes our current knowledge on nanoparticles, their toxic effects, their interactions with mammalian cells and finally current approaches to minimizing their toxicity.

Barium Titanate (BaTiO3) Nanoparticles Exert Cytotoxicity through Oxidative Stress in Human Lung Carcinoma (A549) Cells

Barium titanate (BaTiO3) nanoparticles (BT NPs) have shown exceptional characteristics such as high dielectric constant and suitable ferro-, piezo-, and pyro-electric properties. Thus, BT NPs have shown potential to be applied in various fields including electro-optical devices and biomedicine. However, very limited knowledge is available on the interaction of BT NPs with human cells. This work was planned to study the interaction of BT NPs with human lung carcinoma (A549) cells. Results showed that BT NPs decreased cell viability in a dose- and time-dependent manner. Depletion of mitochondrial membrane potential and induction of caspase-3 and -9 enzyme activity were also observed following BT NP exposure. BT NPs further induced oxidative stress indicated by induction of pro-oxidants (reactive oxygen species and hydrogen peroxide) and reduction of antioxidants (glutathione and several antioxidant enzymes). Moreover, BT NP-induced cytotoxicity and oxidative stress were effectively abrogated by N-acetyl-cysteine (an ROS scavenger), suggesting that BT NP-induced cytotoxicity was mediated through oxidative stress. Intriguingly, the underlying mechanism of cytotoxicity of BT NPs was similar to the mode of action of ZnO NPs. At the end, we found that BT NPs did not affect the non-cancerous human lung fibroblasts (IMR-90). Altogether, BT NPs selectively induced cytotoxicity in A549 cells via oxidative stress. This work warrants further research on selective cytotoxicity mechanisms of BT NPs in different types of cancer cells and their normal counterparts.

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

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

A titanium dioxide/nitrogen-doped graphene quantum dot nanocomposite to mitigate cytotoxicity: synthesis, characterisation, and cell viability evaluation

Titanium dioxide nanoparticles (TiO₂ NPs) have attracted tremendous interest owing to their unique physicochemical properties. However, the cytotoxic effect of TiO₂ NPs remains an obstacle for their wide-scale applications, particularly in drug delivery systems and cancer therapies. In this study, the more biocompatible nitrogen-doped graphene quantum dots (N-GQDs) were successfully incorporated onto the surface of the TiO₂ NPs resulting in a N-GQDs/TiO₂ nanocomposites (NCs). The effects of the nanocomposite on the viability of the breast cancer cell line (MDA-MB-231) was evaluated. The N-GQDs and N-GQDs/TiO₂ NCs were synthesised using a one- and two-pot hydrothermal method, respectively while the TiO₂ NPs were fabricated using microwave-assisted synthesis in the aqueous phase. The synthesised compounds were characterised using Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM) and UV-visible spectrophotometry. The cell viability of the MDA-MB-231 cell line was determined using a CellTiter 96® AQueous One Solution Cell Proliferation (MTS) assay. The obtained results indicated that a monodispersed solution of N-GQDs with particle size 4.40 ± 1.5 nm emitted intense blue luminescence in aqueous media. The HRTEM images clearly showed that the TiO₂ particles (11.46 ± 2.8 nm) are square shaped. Meanwhile, TiO₂ particles were located on the 2D graphene nanosheet surface in N-GQDs/TiO₂ NCs (9.16 ± 2.4 nm). N-GQDs and N-GQDs/TiO₂ NCs were not toxic to the breast cancer cells at 0.1 mg mL⁻¹ and below. At higher concentrations (0.5 and 1 mg mL⁻¹), the nanocomposite was significantly less cytotoxic compared to the pristine TiO₂. In conclusion, this nanocomposite with reduced cytotoxicity warrants further exploration as a new TiO₂-based nanomaterial for biomedical applications, especially as an anti-cancer strategy.

Cytotoxicity mitigation using titanium dioxide/nitrogen-doped graphene quantum dot nanocomposites.

Copper-doped TiO2 photocatalysts: application to drinking water by humic matter degradation

The aim of this study was to determine the photocatalytic performance of copper-doped TiO2 (Cu-TiO2) specimens on the degradation of dissolved organic matter (DOM) represented by a model humic acid (HA). TiO2 was synthesized by sol-gel method from an alkoxide precursor. Cu-doped TiO2 specimens containing 0.25 wt% and 0.50 wt% Cu were prepared by wet impregnation method using sol-gel synthesized as well as bare TiO2 P-25 and characterized by XRD, SEM, XPS, Raman spectroscopy, UV-DRS, and BET measurements. Their photocatalytic activities were evaluated with regard to degradation kinetics of HA in terms of UV-vis and fluorescence spectroscopic parameters and organic contents. HA fluorescence excitation emission matrix (EEM) contour plots indicated that the solar photocatalytic degradation pathway was TiO2-type specific and Cu dopant content.

Appraisal of Comparative Therapeutic Potential of Undoped and Nitrogen-Doped Titanium Dioxide Nanoparticles

Nitrogen-doped and undoped titanium dioxide nanoparticles were successfully fabricated by simple chemical method and characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX), and transmission electron microscopy (TEM) techniques. The reduction in crystalline size of TiO2 nanoparticles (from 20-25 nm to 10-15 nm) was observed by TEM after doping with N. Antibacterial, antifungal, antioxidant, antidiabetic, protein kinase inhibition and cytotoxic properties were assessed in vitro to compare the therapeutic potential of both kinds of TiO2 nanoparticles. All biological activities depicted significant enhancement as a result of addition of N as doping agent to TiO2 nanoparticles. Klebsiella pneumoniae has been illuminated to be the most susceptible bacterial strain out of various Gram-positive and Gram-negative isolates of bacteria used in this study. Good fungicidal activity has been revealed against Aspergillus flavus. 38.2% of antidiabetic activity and 80% of cytotoxicity has been elucidated by N-doped TiO2 nanoparticles towards alpha-amylase enzyme and Artemia salina (brine shrimps), respectively. Moreover, notable protein kinase inhibition against Streptomyces and antioxidant effect including reducing power and % inhibition of DPPH has been demonstrated. This investigation unveils the more effective nature of N-doped TiO2 nanoparticles in comparison to undoped TiO2 nanoparticles indicated by various biological tests. Hence, N-doped TiO2 nanoparticles have more potential to be employed in biomedicine for the cure of numerous infections.

A health concern regarding the protein corona, aggregation and disaggregation

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

Protein nanoparticles are nontoxic, tuneable cell stressors

Aim: Nanoparticle–cell interactions can promote cell toxicity and stimulate particular behavioral patterns, but cell responses to protein nanomaterials have been poorly studied. Results: By repositioning oligomerization domains in a simple, modular self-assembling protein platform, we have generated closely related but distinguishable homomeric nanoparticles. Composed by building blocks with modular domains arranged in different order, they share amino acid composition. These materials, once exposed to cultured cells, are differentially internalized in absence of toxicity and trigger distinctive cell adaptive responses, monitored by the emission of tubular filopodia and enhanced drug sensitivity. Conclusion: The capability to rapidly modulate such cell responses by conventional protein engineering reveals protein nanoparticles as tuneable, versatile and potent cell stressors for cell-targeted conditioning.