Uptake kinetics and nanotoxicity of silica nanoparticles are cell type dependent

Bionano Interactions of Organosilica Nanoparticles with Myeloid Derived Immune Cells

Investigating the interactions between nanomaterials and the cells they are likely to encounter in vivo is a critical aspect of designing nanomedicines for imaging and therapeutic applications. Immune cells such as dendritic cells, macrophages, and myeloid derived suppressor cells have a frontline role in the identification and removal of foreign materials from the body, with interactions shown to be heavily dependent on variables such as nanoparticle size, charge, and surface chemistry. Interactions such as cellular association or uptake of nanoparticles can lead to diminished functionality or rapid clearance from the body, making it critical to consider these interactions when designing and synthesizing nanomaterials for biomedical applications ranging from drug delivery to imaging and biosensing. We investigated the interactions between PEGylated organosilica nanoparticles and naturally endocytic immune cells grown from stem cells in murine bone marrow. Specifically, we varied the particle size from 60 nm up to 1000 nm and investigated the effects of size on immune cell association, activation, and maturation with these critical gatekeeper cells. These results will help inform future design parameters for in vitro and in vivo biomedical applications utilizing organosilica nanoparticles.

Impact of Respiratory Dust on Health: A Comparison Based on the Toxicity of PM2.5, Silica, and Nanosilica

Respiratory dust of different particle sizes in the environment causes diverse health effects when entering the human body and makes acute or chronic damage through multiple systems and organs. However, the precise toxic effects and potential mechanisms induced by dust of different particle sizes have not been systematically summarized. In this study, we described the sources and characteristics of three different particle sizes of dust: PM2.5 (<2.5 μm), silica (<5 μm), and nanosilica (<100 nm). Based on their respective characteristics, we further explored the main toxicity induced by silica, PM2.5, and nanosilica in vivo and in vitro. Furthermore, we evaluated the health implications of respiratory dust on the human body, and especially proposed potential synergistic effects, considering current studies. In summary, this review summarized the health hazards and toxic mechanisms associated with respiratory dust of different particle sizes. It could provide new insights for investigating the synergistic effects of co-exposure to respiratory dust of different particle sizes in mixed environments.

Primary Human Breast Cancer-Associated Endothelial Cells Favor Interactions with Nanomedicines

Cancer nanomedicines predominately rely on transport processes controlled by tumor-associated endothelial cells to deliver therapeutic and diagnostic payloads into solid tumors. While the dominant role of this class of endothelial cells for nanoparticle transport and tumor delivery is established in animal models, the translational potential in human cells needs exploration. Using primary human breast cancer as a model, the differential interactions of normal and tumor-associated endothelial cells with clinically relevant nanomedicine formulations are explored and quantified. Primary human breast cancer-associated endothelial cells exhibit up to ≈2 times higher nanoparticle uptake than normal human mammary microvascular endothelial cells. Super-resolution imaging studies reveal a significantly higher intracellular vesicle number for tumor-associated endothelial cells, indicating a substantial increase in cellular transport activities. RNA sequencing and gene expression analysis indicate the upregulation of transport-related genes, especially motor protein genes, in tumor-associated endothelial cells. Collectively, the results demonstrate that primary human breast cancer-associated endothelial cells exhibit enhanced interactions with nanomedicines, suggesting a potentially significant role for these cells in nanoparticle tumor delivery in human patients. Engineering nanoparticles that leverage the translational potential of tumor-associated endothelial cell-mediated transport into human solid tumors may lead to the development of safer and more effective clinical cancer nanomedicines.

One-pot, degradable, silica nanocarriers with encapsulated oligonucleotides for mitochondrial specific targeting

Mutations in nuclear and mitochondrial genes are responsible for severe chronic disorders such as mitochondrial myopathies. Gene therapy using antisense oligonucleotides is a promising strategy to treat mitochondrial DNA (mtDNA) diseases by blocking the replication of the mutated mtDNA. However, transport vehicles are needed for intracellular, mitochondria-specific transport of oligonucleotides. Nanoparticle (NP) based vectors such as large pore mesoporous silica nanoparticles (LP) often rely on surface complexation of oligonucleotides exposing them to nucleases and limiting mitochondria targeting and controlled release ability. In this work, stable, fluorescent, hollow silica nanoparticles (HSN) that encapsulate and protect oligonucleotides in the hollow core were synthesized by a facile one-pot procedure. Both rhodamine B isothiocyanate and bis[3-(triethoxysilyl)propyl]tetrasulfide were incorporated in the HSN matrix by co-condensation to enable cell tracing, intracellular-specific degradation and controlled oligonucleotide release. We also synthesized LP as a benchmark to compare the oligonucleotide loading and release efficacy of our HSN. Mitochondria targeting was enabled by NP functionalization with cationic, lipophilic Triphenylphosphine (TPP) and, for the first time a fusogenic liposome based carrier, previously reported under the name MITO-Porter. HSN exhibited high oligonucleotide incorporation ratios and release dependent on intracellular degradation. Further, MITO-Porter capping of our NP enabled delayed, glutathione (GSH) responsive oligonucleotide release and mitochondria targeting at the same efficiency as TPP functionalized NP. Overall, our NP are promising vectors for anti-gene therapy of mtDNA disease as well as many other monogenic disorders worldwide.

Prospects and hazards of silica nanoparticles: Biological impacts and implicated mechanisms

With the thrive of nanotechnology, silica nanoparticles (SiNPs) have been extensively adopted in the agriculture, food, cosmetic, and even biomedical industries. Due to the mass production and use, SiNPs inevitably entered the environment, resulting in ecological toxicity and even posing a threat to human health. Although considerable investigations have been conducted to assess the toxicity of SiNPs, the correlation between SiNPs exposure and consequent health risks remains ambiguous. Since the biological impacts of SiNPs can differ from their design and application, the toxicity assessment for SiNPs may be extremely difficult. This review discussed the application of SiNPs in different fields, especially their biomedical use, and documented their potential release pathways into the environment. Meanwhile, the current process of assessing SiNPs-related toxicity on various model organisms and cell lines was also detailed, thus estimating the health threats posed by SiNPs exposure. Finally, the potential toxic mechanisms of SiNPs were also elaborated based on results obtained from both in vivo and in vitro trials. This review generally summarizes the biological effects of SiNPs, which will build up a comprehensive perspective of the application and toxicity of SiNPs.

Development of Cell-Derived Plasma Membrane Vesicles as a Nanoparticle Encapsulation and Delivery System

Background

Developing non-invasive delivery platforms with a high level of structural and/or functional similarity to biological membranes is highly desirable to reduce toxicity and improve targeting capacity of nanoparticles. Numerous studies have investigated the impacts of physicochemical properties of engineered biomimetic nanoparticles on their interaction with cells, yet technical difficulties have led to the search for better biomimetics, including vesicles isolated directly from live cells. Cell-derived giant plasma membrane vesicles (GPMVs), in particular, offer a close approximation of the intact cell plasma membrane by maintaining the latter's compositional complexity, protein positioning in a fluid-mosaic pattern, and physical and mechanical properties. Thus, to overcome technical barriers of prior nanoparticle delivery approaches, we aimed to develop a novel method using GPMVs to encapsulate a variety of engineered nanoparticles, then use these core-shell, nanoparticle-GPMV vesicle structures to deliver cargo to other cells.

Results

The GPMV system in this study was generated by chemically inducing vesiculation in A549 cells, a model human alveolar epithelial line. These cell-derived GPMVs retained encapsulated silica nanoparticles (50 nm diameter) for at least 48 hours at 37 °C. GPMVs showed nearly identical lipid and protein membrane profiles as the parental cell plasma membrane, with or without encapsulation of nanoparticles. Notably, GPMVs were readily endocytosed in the parental A549 cell line as well as the human monocytic THP-1 cell line. Higher cellular uptake levels were observed for GPMV-encapsulated nanoparticles compared to control groups, including free nanoparticles. Further, GPMVs delivered a variety of nanoparticles to parental cells with reduced cytotoxicity compared to free nanoparticles at concentrations that were otherwise significantly toxic.

Conclusions

We have introduced a novel technique to load nanoparticles within the cell plasma membrane during the GPMV vesiculation process. These GPMVs are capable of (a) encapsulating different types of nanoparticles (including larger and not highly-positively charged bodies that have been technically challenging cargoes) using a parental cell uptake technique, and (b) improving delivery of nanoparticles to cells without significant cytotoxicity. Ultimately, endogenous surface membrane proteins and lipids can optimize the physicochemical properties of cell membrane-derived vesicles, which could lead to highly effective cell membrane-based nanoparticle/drug delivery systems.

Cellular uptake and retention studies of silica nanoparticles utilizing senescent fibroblasts

Understanding the interplay between nanoparticles (NPs) and cells is essential to designing more efficient nanomedicines. Previous research has shown the role of the cell cycle having impact on the efficiency of cellular uptake and accumulation of NPs. However, there is a limited investigation into the biological fate of NPs in cells that are permanently withdrawn from the cell cycle. Here we utilize senescent WI-38 fibroblasts, which do not divide and provide a definitive model for tracking the biological fate of silica nanoparticles (SiNPs) independent of cell cycle. We use several methods to measure the cellular uptake kinetics and intracellular retention of SiNPs, including confocal laser scanning microscopy (CLSM), flow cytometry, and transmission electron microscopy (TEM). We demonstrate that SiNPs readily enter into senescent cells. Once internalized, SiNPs do not exit and accumulate in the cytoplasm for long term. Our study provides a basis for future development of NP-based tools that can detect and target senescent cells for therapy.

Integration of In Vitro and In Vivo Models to Predict Cellular and Tissue Dosimetry of Nanomaterials Using Physiologically Based Pharmacokinetic Modeling

Nanomaterials (NMs) have been increasingly used in a number of areas, including consumer products and nanomedicine. Target tissue dosimetry is important in the evaluation of safety, efficacy, and potential toxicity of NMs. Current evaluation of NM efficacy and safety involves the time-consuming collection of pharmacokinetic and toxicity data in animals and is usually completed one material at a time. This traditional approach no longer meets the demand of the explosive growth of NM-based products. There is an emerging need to develop methods that can help design safe and effective NMs in an efficient manner. In this review article, we critically evaluate existing studies on in vivo pharmacokinetic properties, in vitro cellular uptake and release and kinetic modeling, and whole-body physiologically based pharmacokinetic (PBPK) modeling studies of different NMs. Methods on how to simulate in vitro cellular uptake and release kinetics and how to extrapolate cellular and tissue dosimetry of NMs from in vitro to in vivo via PBPK modeling are discussed. We also share our perspectives on the current challenges and future directions of in vivo pharmacokinetic studies, in vitro cellular uptake and kinetic modeling, and whole-body PBPK modeling studies for NMs. Finally, we propose a nanomaterial in vitro to in vivo extrapolation via physiologically based pharmacokinetic modeling (Nano-IVIVE-PBPK) framework for high-throughput screening of target cellular and tissue dosimetry as well as potential toxicity of different NMs in order to meet the demand of efficient evaluation of the safety, efficacy, and potential toxicity of a rapidly increasing number of NM-based products.

Silica nanoparticles: Biomedical applications and toxicity

Silica nanoparticles (SiNPs) are composed of silicon dioxide, the most abundant compound on Earth, and are used widely in many applications including the food industry, synthetic processes, medical diagnosis, and drug delivery due to their controllable particle size, large surface area, and great biocompatibility. Building on basic synthetic methods, convenient and economical strategies have been developed for the synthesis of SiNPs. Numerous studies have assessed the biomedical applications of SiNPs, including the surface and structural modification of SiNPs to target various cancers and diagnose diseases. However, studies on the in vitro and in vivo toxicity of SiNPs remain in the exploratory stage, and the toxicity mechanisms of SiNPs are poorly understood. This review covers recent studies on the biomedical applications of SiNPs, including their uses in drug delivery systems to diagnose and treat various diseases in the human body. SiNP toxicity is discussed in terms of the different systems of the human body and the individual organs in those systems. This comprehensive review includes both fundamental discoveries and exploratory progress in SiNP research that may lead to practical developments in the future.

Chiral NIR-II fluorescent Ag2S quantum dots with stereospecific biological interactions and tumor accumulation behaviors

Near-infrared II (NIR-II) fluorescent nanoprobes hold great potential for biomedical applications. Elucidating the relationship between surface properties of NIR-II nanoprobes and their biological behaviors is particularly important for future probe design and their performance optimization. Despite the rapid development of NIR-II nanoprobes, the distinct role of surface chirality on their biological fates has rarely been exploited. Herein, chiral NIR-II fluorescent Ag₂S quantum dots (QDs) are synthesized to investigate the relationship between their chirality and biological functions at both in vitro and in vivo levels. D-/L-Ag₂S QDs exhibit significant differences on their interactions with serum proteins, which further affect the cellular uptake. As a result, D-Ag₂S QDs can be internalized with higher efficiency (over 2-fold) than that of L-Ag₂S QDs. Moreover, in vivo studies reveal that the chirality determines the primary localization of these chiral QDs, where a more efficient renal elimination of D-Ag₂S QDs was observed than that of L-Ag₂S QDs. Importantly, D-Ag₂S QDs show preferential accumulation in tumor region than that of L-Ag₂S QDs in orthotopic kidney tumor model, which points out a new avenue of enhancing targeting capabilities of nanoprobes by engineering their surface chirality.

Influence of Critical Parameters on Cytotoxicity Induced by Mesoporous Silica Nanoparticles

Mesoporous Silica Nanoparticles (MSNs) have received increasing attention in biomedical applications due to their tuneable pore size, surface area, size, surface chemistry, and thermal stability. The biocompatibility of MSNs, although generally believed to be satisfactory, is unclear. Physicochemical properties of MSNs, such as diameter size, morphology, and surface charge, control their biological interactions and toxicity. Experimental conditions also play an essential role in influencing toxicological results. Therefore, the present study includes studies from the last five years to statistically analyse the effect of various physicochemical features on MSN-induced in-vitro cytotoxicity profiles. Due to non-normally distributed data and the presence of outliers, a Kruskal-Wallis H test was conducted on different physicochemical characteristics, including diameter sizes, zeta-potential measurements, and functionalisation of MSNs, based on the viability results, and statistical differences were obtained. Subsequently, pairwise comparisons were performed using Dunn's procedure with a Bonferroni correction for multiple comparisons. Other experimental parameters, such as type of cell line used, cell viability measurement assay, and incubation time, were also explored and analysed for statistically significant results.

The morphological role of ligand inhibitors in blocking receptor- and clathrin-mediated endocytosis

Cells often internalize particles through endocytic pathways that involve the binding between cell receptors and particle ligands, which drives the cell membrane to wrap the particle into a delivery vesicle. Previous findings showed that receptor-mediated endocytosis is impossible for spherical particles smaller than a minimum size because of the energy barrier created by membrane bending. In this study, we investigate the morphological role of ligand inhibitors in blocking endocytosis, inspired by antibodies that inhibit virus ligands to prevent infection. While ligand inhibitors have the obvious effect of reducing the driving force due to adhesion, they also have a nontrivial (morphological) impact on the entropic and elastic energy of the system. We determine the necessary conditions for endocytosis by considering the additional energy barrier due to the membrane bending to wrap the inhibiting protrusions. We find that inhibitors increase the minimum radius previously reported, depending on their density and size. In addition, we extend this result to the case of clathrin-mediated endocytosis, which is the most common pathway for virus entry. The assembly of a clathrin coat with a spontaneous curvature increases the energy barrier and sets a maximum particle size (in agreement with experimental observations on spherical particles). Our investigation suggests that morphological considerations can inform the optimal design of neutralizing viral antibodies and new strategies for targeted nanomedicine.

Interaction of monodispersed strontium containing bioactive glass nanoparticles with macrophages

The cellular response of murine primary macrophages to monodisperse strontium containing bioactive glass nanoparticles (SrBGNPs), with diameters of 90 ± 10 nm and a composition (mol%) of 88.8 SiO₂-1.8CaO-9.4SrO (9.4% Sr-BGNPs) was investigated for the first time. Macrophage response is critical as applications of bioactive nanoparticles will involve the nanoparticles circulating in the blood stream and macrophages will be the first cells to encounter the particles, as part of inflammatory response mechanisms. Macrophage viability and total DNA measurements were not decreased by particle concentrations of up to 250 μg/mL. The Sr-BGNPs were actively internalised by the macrophages via formation of endosome/lysosome-like vesicles bordered by a membrane inside the cells. The Sr-BGNPs degraded inside the cells, with the Ca and Sr maintained inside the silica network. When RAW264.7 cells were incubated with Sr-BGNPs, the cells were polarised towards the pro-regenerative M2 population rather than the pro-inflammatory M1 population. Sr-BGNPs are potential biocompatible vehicles for therapeutic cation delivery for applications in bone regeneration.

Effects of Nonporous Silica Nanoparticles on Human Trabecular Meshwork Cells

PRECIS

Silica nanoparticles (SiNPs), which are potential drug carriers for glaucoma treatment, may induce mild dose-dependent cytotoxicity but not so severe as to compromise a mammalian target of rapamycin (mTOR) pathway in immortalized trabecular meshwork (TM) cells.

PURPOSE

Nanoparticle-based ophthalmic drug delivery is a promising field of drug development. In this study, we evaluated the effect of nonporous SiNPs on human TM cells.

METHODS

TM cells were exposed to different concentrations (0 to 100 µg/mL) of SiNPs (50, 100, and 150 nm) for up to 48 hours. Transmission electron microscopy confirmed the intracellular distribution of SiNPs. Cellular viability assay, reactive oxygen species generation, autophagy, and activation of the mTOR pathway were evaluated. Histologic analysis of the TM structure was performed after intracameral injection of SiNPs (0.05 mL of 200 µg/mL concentration) in rabbits.

RESULTS

SiNPs were taken up by TM cells and localized in the cytoplasm. Neither nuclear entry nor mitochondrial damage was observed. SiNPs induced a mild but dose-dependent increase of lactate dehydrogenase. However, neither increase of intracellular reactive oxygen species levels nor apoptosis was observed after SiNPs exposure. Significant coactivation of autophagy and the mTOR pathway were observed with exposure to SiNPs. Aqueous plexus structure was well maintained without inflammation in rabbits after SiNPs exposure.

CONCLUSIONS

SiNPs induce mild and dose-dependent cytotoxicity in TM cells. However, the toxicity level is not enough to compromise the mTOR pathway of TM cells and histologic structure of the aqueous plexus tissue.

Green synthesis of silica nanoparticles from olive residue and investigation of their anticancer potential

Aim: To synthesize silica nanoparticles (SNPs) from olive residue with anticancer properties. Methods: SNPs were synthesized from olive residue ash (ORA). After characterization, cytotoxicity of the SNPs was assessed in vitro, with measurement of reactive oxygen species (ROS) levels. Results: The average diameter of the synthesized SNPs was 30-40 nm, and zeta potential analysis suggested they were stable. The synthesized SNPs were less cytotoxic than commercially available SNPs against fibroblast cells, and the cytotoxic effect on breast cancer cells was significantly higher compared with fibroblast cells. SNPs showed greater uptake into cancer cells where there was greater production of free radicals. Conclusion: SNPs synthesized from ORA have potential anticancer applications because they are more cytotoxic toward cancer cells than fibroblast cells.

Interplay of Nanoparticle Properties during Endocytosis

Nanoparticles (NPs) have been widely applied as drug carriers in drug delivery, due to their unique physical and structural properties. To achieve the drug delivery purpose, receptor-mediated endocytosis is a primary explored mechanism to internalize NPs into tumor cells. During the endocytosis process, properties of NPs, including size, shape, and surface functionality, play an important role in determining the final drug delivery efficacy. Many of these NP properties have been extensively explored individually. However, the multiple NP properties naturally interplay with each other in the endocytosis process to determine the internalization efficiency together. Therefore, it is significantly important to understand the interplay of different NP properties to improve the NP’s final delivery efficacy. In this review, we focus on the interplay of NPs properties on the endocytosis process to summarize the relevant experimental observations and physical mechanisms. Particularly, three different aspects are discussed in detail, including the interplay between size and shape; size and elasticity; shape and elasticity. We have summarized the most recent works and highlighted that building up systematic understandings for the complex interplay between NP properties can greatly help a better design of NP platforms for drug delivery.

Understanding nanoparticle endocytosis to improve targeting strategies in nanomedicine

Nanoparticles (NPs) have attracted considerable attention in various fields, such as cosmetics, the food industry, material design, and nanomedicine. In particular, the fast-moving field of nanomedicine takes advantage of features of NPs for the detection and treatment of different types of cancer, fibrosis, inflammation, arthritis as well as neurodegenerative and gastrointestinal diseases. To this end, a detailed understanding of the NP uptake mechanisms by cells and intracellular localization is essential for safe and efficient therapeutic applications. In the first part of this review, we describe the several endocytic pathways involved in the internalization of NPs and we discuss the impact of the physicochemical properties of NPs on this process. In addition, the potential challenges of using various inhibitors, endocytic markers and genetic approaches to study endocytosis are addressed along with the principal (semi) quantification methods of NP uptake. The second part focuses on synthetic and bio-inspired substances, which can stimulate or decrease the cellular uptake of NPs. This approach could be interesting in nanomedicine where a high accumulation of drugs in the target cells is desirable and clearance by immune cells is to be avoided. This review contributes to an improved understanding of NP endocytic pathways and reveals potential substances, which can be used in nanomedicine to improve NP delivery.

Kinetics of nanoparticle uptake into and distribution in human cells

Whether one wishes to optimise drug delivery using nano-sized carriers or avoid hazard posed by engineered nanomaterials, the kinetics of nanoparticle uptake into human cells and their subsequent intracellular distribution is key. Unique properties of the nanoscale implies that such nanoparticles are taken up and trafficked in a different fashion compared to molecular species. In this review, we discuss in detail how to describe the kinetics of nanoparticle uptake and intracellular distribution, using previous studies for illustration. We also cover the extracellular kinetics, particle degradation, endosomal escape and cell division, ending with an outlook on the future of kinetic studies.

Comparative Toxicity of Fly Ash: An In Vitro Study

Fly ash produced during coal combustion is one of the major sources of air and water pollution, but the data on the impact of micrometer-size fly ash particles on human cells is still incomplete. Fly ash samples were collected from several electric power stations in the United States (Rockdale, TX; Dolet Hill, Mansfield, LA; Rockport, IN; Muskogee, OK) and from a metallurgic plant located in the Russian Federation (Chelyabinsk Electro-Metallurgical Works OJSC). The particles were characterized using dynamic light scattering, atomic force, and hyperspectral microscopy. According to chemical composition, the fly ash studied was ferro-alumino-silicate mineral containing substantial quantities of Ca, Mg, and a negligible concentration of K, Na, Mn, and Sr. The toxicity of the fly ash microparticles was assessed in vitro using HeLa cells (human cervical cancer cells) and Jurkat cells (immortalized human T lymphocytes). Incubation of cells with different concentrations of fly ash resulted in a dose-dependent decrease in cell viability for all fly ash variants. The most prominent cytotoxic effect in HeLa cells was produced by the ash particles from Rockdale, while the least was produced by the fly ash from Chelyabinsk. In Jurkat cells, the lowest toxicity was observed for fly ash collected from Rockport, Dolet Hill and Muscogee plants. The fly ash from Rockdale and Chelyabinsk induced DNA damage in HeLa cells, as revealed by the single cell electrophoresis, and disrupted the normal nuclear morphology. The interaction of fly ash microparticles of different origins with cells was visualized using dark-field microscopy and hyperspectral imaging. The size of ash particles appeared to be an important determinant of their toxicity, and the smallest fly ash particles from Chelyabinsk turned out to be the most cytotoxic to Jukart cells and the most genotoxic to HeLa cells.

Uptake and Intracellular Trafficking Studies of Multiple Dye-Doped Core-Shell Silica Nanoparticles in Lymphoid and Myeloid Cells

Introduction

Since most biologically active macromolecules are natural nanostructures, operating in the same scale of biomolecules gives the great advantage to enhance the interaction with cellular components. Noteworthy efforts in nanotechnology, particularly in biomedical and pharmaceutical fields, have propelled a high number of studies on the biological effects of nanomaterials. Moreover, the determination of specific physicochemical properties of nanomaterials is crucial for the evaluation and design of novel safe and efficient therapeutics and diagnostic tools. In this in vitro study, we report a physicochemical characterisation of fluorescent silica nanoparticles (NPs), interacting with biological models (U937 and PBMC cells), describing the specific triggered biologic response.

Methods

Flow Cytometric and Confocal analyses are the main method platforms. However TEM, NTA, DLS, and chemical procedures to synthesize NPs were employed.

Results

NT_B700 NPs, employed in this study, are fluorescent core-shell silica nanoparticles, synthesized through a micelle-assisted method, where the fluorescence energy transfer process, known as FRET, occurs at a high efficiency rate. Using flow cytometry and confocal microscopy, we observed that NT_B700 NP uptake seemed to be a rapid, concentration-, energy- and cell type-dependent process, which did not induce significant cytotoxic effects. We did not observe a preferred route of internalization, although their size and the possible aggregated state could influence their extrusion. At this level of analysis, our investigation focuses on lysosome and mitochondria pathways, highlighting that both are involved in NP co-localization. Despite the main mitochondria localization, NPs did not induce a significant increase of intracellular ROS, known inductors of apoptosis, during the time course of analyses. Finally, both lymphoid and myeloid cells are able to release NPs, essential to their biosafety.

Discussion

These data allow to consider NT_B700 NPs a promising platform for future development of a multifunctional system, by combining imaging and localized therapeutic applications in a unique tool.

Differences of the tumour cell glycocalyx affect binding of capsaicin-loaded chitosan nanocapsules

The glycocalyx regulates the interaction of mammalian cells with extracellular molecules, such as cytokines. However, it is unknown to which extend the glycocalyx of distinct cancer cells control the binding and uptake of nanoparticles. In the present study, exome sequencing data of cancer patients and analysis of distinct melanoma and bladder cancer cell lines suggested differences in cancer cell-exposed glycocalyx components such as heparan sulphate. Our data indicate that glycocalyx differences affected the binding of cationic chitosan nanocapsules (Chi-NCs). The pronounced glycocalyx of bladder cancer cells enhanced the internalisation of nanoencapsulated capsaicin. Consequently, capsaicin induced apoptosis in the cancer cells, but not in the less glycosylated benign urothelial cells. Moreover, we measured counterion condensation on highly negatively charged heparan sulphate chains. Counterion condensation triggered a cooperative binding of Chi-NCs, characterised by a weak binding rate at low Chi-NC doses and a strongly increased binding rate at high Chi-NC concentrations. Our results indicate that the glycocalyx of tumour cells controls the binding and biological activity of nanoparticles. This has to be considered for the design of tumour cell directed nanocarriers to improve the delivery of cytotoxic drugs. Differential nanoparticle binding may also be useful to discriminate tumour cells from healthy cells.

Activatable superparamagnetic iron oxide nanoparticles scavenge reactive oxygen species in macrophages and endothelial cells

Reactive oxygen species (ROS) are key markers of inflammation, with varying levels of superoxide indicating the degree of inflammation. Inflammatory diseases remain the leading cause of death in the developed world. Previously, we showed that interpolymer complexed superparamagnetic iron oxide nanoparticles (IPC-SPIOs) are capable of decomplexing and activating T2 magnetic resonance (MR) contrast in superoxide-rich environments. Here, we investigate the ability of IPC-SPIOs to scavenge ROS in immune and endothelial cells which should activate the superparamagnetic core. In exogenously generated superoxide, ROS scavenging by the nanoparticles was concentration dependent and ranged from 5% to over 50% of available ROS. A statistically significant reduction in ROS was observed in the presence of IPCSPIOs compared to poly(ethylene glycol)-coated SPIOs (PEG-SPIOs). During in vitro cellular assays, a reduction in ROS was observed in macrophages, monocytes, and human endothelial cells. Macrophages and endothelial cells experienced significantly higher ROS reduction compared to monocytes. ROS scavenging peaked 12 hours post-exposure to IPC-SPIOs in most studies, with some cell samples experiencing extended scavenging with increasing IPC-SPIO concentration. At the tested concentrations, particles were not cytotoxic, and confocal imaging showed localization of particles within cells. These findings demonstrate the potential of IPC-SPIOs as activatable MR contrast agents capable of activating under inflammation-induced cellular redox conditions as reporters of inflammatory disease severity or staging.

Iron Oxide Nanoparticle-Induced Autophagic Flux Is Regulated by Interplay between p53-mTOR Axis and Bcl-2 Signaling in Hepatic Cells

Iron oxide-based nanoparticles have been repeatedly shown to affect lysosomal-mediated signaling. Recently, nanoparticles have demonstrated an ability to modulate autophagic flux via lysosome-dependent signaling. However, the precise underlying mechanisms of such modulation as well as the impact of cellular genetic background remain enigmatic. In this study, we investigated how lysosomal-mediated signaling is affected by iron oxide nanoparticle uptake in three distinct hepatic cell lines. We found that nanoparticle-induced lysosomal dysfunction alters sub-cellular localization of pmTOR and p53 proteins. Our data indicate that alterations in the sub-cellular localization of p53 protein induced by nanoparticle greatly affect the autophagic flux. We found that cells with high levels of Bcl-2 are insensitive to autophagy initiated by nanoparticles. Altogether, our data identify lysosomes as a central hub that control nanoparticle-mediated responses in hepatic cells. Our results provide an important fundamental background for the future development of targeted nanoparticle-based therapies.

SiO2-PVA-Fe(acac)3 Hybrid Based Superparamagnetic Nanocomposites for Nanomedicine: Morpho-textural Evaluation and In Vitro Cytotoxicity Assay

A facile sol-gel route has been applied to synthesize hybrid silica-PVA-iron oxide nanocomposite materials. A step-by-step calcination (processing temperatures up to 400 °C) was applied in order to oxidize the organics together with the iron precursor. Transmission electron microscopy, X-ray diffraction, small angle neutron scattering, and nitrogen porosimetry were used to determine the temperature-induced morpho-textural modifications. In vitro cytotoxicity assay was conducted by monitoring the cell viability by the means of MTT assay to qualify the materials as MRI contrast agents or as drug carriers. Two cell lines were considered: the HaCaT (human keratinocyte cell line) and the A375 tumour cell line of human melanoma. Five concentrations of 10 µg/mL, 30 µg/mL, 50 µg/mL, 100 µg/mL, and 200 µg/mL were tested, while using DMSO (dimethylsulfoxid) and PBS (phosphate saline buffer) as solvents. The HaCaT and A375 cell lines were exposed to the prepared agent suspensions for 24 h. In the case of DMSO (dimethyl sulfoxide) suspensions, the effect on human keratinocytes migration and proliferation were also evaluated. The results indicate that only the concentrations of 100 μg/mL and 200 μg/mL of the nanocomposite in DMSO induced a slight decrease in the HaCaT cell viability. The PBS based in vitro assay showed that the nanocomposite did not present toxicity on the HaCaT cells, even at high doses (200 μg/mL agent).

Nanoparticles and organized lipid assemblies: from interaction to design of hybrid soft devices

This contribution reviews the state of art on hybrid soft matter assemblies composed of inorganic nanoparticles (NP) and lamellar or non-lamellar lipid bilayers. After a short outline of the relevant energetic contributions, we address the interaction of NPs with synthetic lamellar bilayers, meant as cell membrane mimics. We then review the design of hybrid nanostructured materials composed of lipid bilayers and some classes of inorganic NPs, with particular emphasis on the effects on the amphiphilic phase diagram and on the additional properties contributed by the NPs. Then, we present the latest developments on the use of lipid bilayers as coating agents for inorganic NPs. Finally, we remark on the main achievements of the last years and our vision for the development of the field.

Acute Exposure to SiO2 Nanoparticles Affects Protein Synthesis in Bergmann Glia Cells

Attractive due to an alleged high biocompatibility, silica nanoparticles have been widely used in the field of nanomedicine; however, their proven capacity to induce the synthesis and release of pro-inflammatory cytokines in several cellular models has raised concern about their safety. Glutamate, the main excitatory amino acid transmitter triggers a wide variety of signal transduction cascades that regulate protein synthesis at transcriptional and translational levels. A stimulus-dependent dynamic change in the protein repertoire in neurons and glia cells is the molecular framework of higher brain functions. Within the cerebellum, Bergmann glia cells are the most abundant non-neuronal cells and span the entire molecular layer of the cerebellar cortex, wrapping the synapses in this structure. Taking into consideration the functional role of Bergmann glia in terms of the recycling of glutamate, lactate supply to neurons, and prevention of neurotoxic insults, we decided to investigate the possibility that silica nanoparticles affect Bergmann glia and by these means alter the major excitatory neurotransmitter system in the brain. To this end, we exposed cultured chick cerebellar Bergmann glia cells to silica nanoparticles and measured [³⁵S]-methionine incorporation into newly synthesized polypeptides. Our results demonstrate that exposure of the cultured cells to silica nanoparticles exerts a time- and dose-dependent modulation of protein synthesis. Furthermore, altered patterns of eukaryotic initiation factor 2 alpha and eukaryotic elongation factor 2 phosphorylation were present upon nanoparticle exposure. These results demonstrate that glia cells respond to the presence of this nanomaterial modifying their proteome, presumably in an effort to overcome any plausible neurotoxic effect.

Thymoquinone loaded mesoporous silica nanoparticles retard cell invasion and enhance in vitro cytotoxicity due to ROS mediated apoptosis in HeLa and MCF-7 cell lines

Thymoquinone (TQ) loaded monodispersed mesoporous silica nanoparticles (TQ-MSNPs) with size of 188 ± 3 nm were prepared and characterized using DLS, TEM and FTIR. These TQ-MSNPs overcome the limitations of free TQ like hydrophobicity, low aqueous and photo stability and thus enhance its anticancer activity. In vitro release kinetics showed biphasic drug release where up to 50% was released in first 8 h and subsequently 98% released after 48 h. Enhanced cytotoxicity of TQ-MSNPs was observed against MCF-7 and HeLa cell lines as compared to free TQ. DAPI and Annexin V-FITC/PI staining confirmed the induction of apoptosis in cancer cells following treatment with TQ-MSNPs. Also, TQ-MSNPs exhibited enhanced anti-invasion properties against both cell lines as very low concentration of loaded TQ imparts similar benefits as free TQ. Both TQ and TQ-MSNPs exerted their cytotoxicity via reactive oxygen species (ROS) generation, as addition of an antioxidant NAC attenuated their killing activity.

Size-controlled DNA-cross-linked hydrogel coated silica nanoparticles served as a ratiometric fluorescent probe for the detection of adenosine triphosphate in living cells

Herein, we have designed a ratiometric fluorescent nanoprobe for adenosine triphosphate sensing and imaging in living cells, based on silica nanoparticles and a DNA-functionalized hybrid hydrogel. This ratiometric detecting method could validly avoid false-positive signals. Due to its controllable size, favorable biocompatibility and biostability, the nanohydrogel exhibited high cellular permeability and fast response in living cells.

Concepts of nanoparticle cellular uptake, intracellular trafficking, and kinetics in nanomedicine

Nanoparticle-based therapeutics and diagnostics are commonly referred to as nanomedicine and may significantly impact the future of healthcare. However, the clinical translation of these technologies is challenging. One of these challenges is the efficient delivery of nanoparticles to specific cell populations and subcellular targets in the body to elicit desired biological and therapeutic responses. It is critical for researchers to understand the fundamental concepts of how nanoparticles interact with biological systems to predict and control in vivo nanoparticle transport for improved clinical benefit. In this overview article, we review and discuss cellular internalization pathways, summarize the field`s understanding of how nanoparticle physicochemical properties affect cellular interactions, and explore and discuss intracellular nanoparticle trafficking and kinetics. Our overview may provide a valuable resource for researchers and may inspire new studies to expand our current understanding of nanotechnology-biology interactions at cellular and subcellular levels with the goal to improve clinical translation of nanomedicines.

Development of Novel EE/Alginate Polyelectrolyte Complex Nanoparticles for Lysozyme Delivery: Physicochemical Properties and In Vitro Safety

The number of biologic drugs has increased in the pharmaceutical industry due to their high therapeutic efficacy and selectivity. As such, safe and biocompatible delivery systems to improve their stability and efficacy are needed. Here, we developed novel cationic polymethacrylate-alginate (EE-alginate) pNPs for the biologic drug model lysozyme (Lys). The impact of variables such as total charge and charge ratios over nanoparticle physicochemical properties as well as their influence over in vitro safety (viability/proliferation and cell morphology) on HeLa cells was investigated. Our results showed that electrostatic interactions between the EE-alginate and lysozyme led to the formation of EE/alginate Lys pNPs with reproducible size, high stability due to their controllable zeta potential, a high association efficiency, and an in vitro sustained Lys release. Selected formulations remained stable for up to one month and Fourier transform-Infrared (FT-IR) showed that the functional groups of different polymers remain identifiable in combined systems, suggesting that Lys secondary structure is retained after pNP synthesis. EE-alginate Lys pNPs at low concentrations are biocompatible, while at high concentrations, they show cytotoxic for HeLa cells, and this effect was found to be dose-dependent. This study highlights the potential of the EE-alginate, a novel polyelectrolyte complex nanoparticle, as an effective and viable nanocarrier for future drug delivery applications.

Local Delivery and Sustained-Release of Nitric Oxide Donor Loaded in Mesoporous Silica Particles for Efficient Treatment of Primary Open-Angle Glaucoma

Nitric oxide (NO) donors are ideal drug candidates for reducing intraocular pressure in the treatment of glaucoma. However, poor cornea penetration, short duration of efficacy, and narrow therapeutic index of most NO donors obstruct their clinical applications in glaucoma treatment. This study reports a novel NO donor delivery system based on mesoporous silica nanoparticles that can readily overcome the above difficulties and deliver the NO-donating drug sodium nitroprusside to the target tissues (trabecular meshwork and Schlemm's canal). Mesoporous silica nanoparticles loaded with sodium nitroprusside can produce more exogenous NO and sustain higher NO concentration in animal eye models, which significantly extend the duration of intraocular pressure reduction from 3 to 48 h with only 1/40 of the dose of sodium nitroprusside solution. These findings open up the possibility of mesoporous silica nanoparticles loading sodium nitroprusside for effective management of ocular hypertension.

Co-exposure subacute toxicity of silica nanoparticles and lead acetate on cardiovascular system

Background

The harmful effects following the release of nanomaterials into environment are of great concern today.

Purpose

In this study, subacute effect due to co-exposure to low-dose silica nanoparticles (SiNPs) and lead acetate (Pb) on cardiovascular system was detected in Sprague Dawley male rats.

Materials and Methods

Histopathological and ultrastructural changes of heart, aortic arch and abdominal aorta were detected. Blood routine and blood biochemistry examinations were used to show the changes of blood components. The fibrinolytic and plasmin factors, inflammation-related factors and myocardial-related enzyme in serum were analysised by ELISA and Western blot assay.

Results

Histopathological and ultrastructural examination of heart, aortic arch, and abdominal aorta showed that serious damage occurred in co-exposure group (n=6/group). Blood routine examination showed that leukocytosis and thrombocytopenia increased markedly, while changes in the erythrocyte count were not obvious in the co-exposure group. The expression of alanine transaminase (ALT) decreased obviously in co-exposure group, while no significant changes were noted in the expression of aspartate aminotransferase (AST), cholesterol (CHO), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C) in the co-exposure group on blood biochemistry analysis. In addition, data from ELISA analysis showed that the levels of fibrinolytic and plasmin factors, including thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), tissue-type plasminogen activator (t-PA), tissue factor pathway inhibitor (TFPI), and antithrombin III (AT III), were decreased, while those of human fibrinogen (FIB) and D-dimer (D2D) increased significantly in the co-exposure group. Moreover, the myocardial-related enzyme in serum, tested by ELISA, and cardiovascular-related protein expression of atrial natriuretic peptide and brain natriuretic peptide, tested by Western blot assay, was increased in the heart. Furthermore, the expression of inflammation factors such as C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) was increased in heart tissue subjected to combined exposure, which was manifested by Western blot assay, while the protein levels of angiotensin II (ANG II) and endothelin 1 were (ET-1) elevated in blood vessels in the co-exposure group.

Conclusion

In conclusion, the major interactions involved in subacute toxicity due to co-exposure to low doses of SiNPs and Pb on cardiovascular system were expected to be additive and synergistic in nature. Co-exposure to SiNPs and Pb could aggravate the cardiovascular toxicity via endothelial damage, hypercoagulation, and cardiac injury in vivo.

Effect of the development of a cell barrier on nanoparticle uptake in endothelial cells

In order to improve the current success of nanomedicine, a better understanding of how nano-sized materials interact with and are processed by cells is required. Typical in vitro nanoparticle-cell interaction studies often make use of cells cultured at different cell densities. However, in vivo, for their successful delivery to the target tissue, nanomedicines need to overcome several barriers, such as endothelial and epithelial cell barriers. Unlike sub-confluent or confluent cell cultures, cell barriers are tight cell monolayers, expressing a series of specialized tight junction proteins between adjacent cells to limit paracellular transport and ensure close cell-to-cell interactions. A clear understanding on how the development of cells into a cell barrier may affect the uptake of nano-sized drug carriers is still missing. To this aim, here, human primary umbilical vein endothelial cells (HUVEC) are used as a model cell line to form endothelial cell barriers. Then, nanoparticle uptake is assessed in the developed endothelial barriers and compared to the uptake in sub-confluent or confluent HUVEC cultures. The results clearly show that the organization of cells into a cell barrier leads to a differential gene expression of endocytic markers, and - interestingly - this is accompanied by reduced nanoparticle uptake levels. Transport inhibitors are used to characterise the mechanisms involved in the uptake. However, we show that some of them can strongly compromise barrier integrity, thus impairing the interpretation of the outcomes, and overall, only a partial inhibition of nanoparticle uptake could be obtained.

Biocompatible properties of nano-drug carriers using TiO2-Au embedded on multiwall carbon nanotubes for targeted drug delivery

Nanomaterial-based drug carriers have become a hot spot of research at the interface of nanotechnology and biomedicine because they allow efficient loading, targeted delivery, controlled release of drugs, and therefore are promising for biomedical applications. The current study made an attempt to decorate the multiwalled carbon nanotubes (MWCNT) with titanium dioxide‑gold nanoparticles in order to enhance the biocompatibility for doxorubicin (DOX) delivery. The successful synthesis of nano drug carrier (NDC) was confirmed by XRD, XPS and UV-Visible spectroscopy. FESEM and TEM revealed that the morphology of NDC can be controlled by manipulating the reaction duration, MWCNT concentration and TiO₂-Au source concentration. Results showed that TiO₂ and Au nanoparticles were well coated on MWCNT. NDC had finely tuned biocompatible properties, as elucidated by hemolytic and antimicrobial assays. NDC also showed a high antioxidant potential, 80.7% expressed as ascorbic acid equivalents. Commercial DOX drug was utilized to treat A549 and MCF7 cancer cell lines showing improved efficiency by formulating it with NDC, which selectively delivered at the pH 5.5 with drug loading capacity of 0.45 mg/mL. The drug releasing capacity achieved by NDC was 90.66% for 10 h, a performance that far encompasses a wide number of current literature reports.

Multiplex Photoluminescent Silicon Nanoprobe for Diagnostic Bioimaging and Intracellular Analysis

Herein, a label-free multiplex photoluminescent silicon nanoprobe (PLSN-probe) is introduced as a potential substitute for quantum dots (QDs) in bioimaging. An inherently non-photoluminescent silicon substrate is altered to create the PLSN-probe, to overcome the major drawbacks of presently available QDs. Additionally, crystallinity alterations of the multiplane crystalline PLSN-probes lead to broad absorption and multiplex fluorescence emissions, which are attributed to the simultaneous existence of multiple crystal planes. The PLSN-probe not only demonstrates unique optical properties that can be exploited for bioimaging but also exhibits cell-selective uptake that allows the differentiation and diagnosis of HeLa and fibroblast cells. Moreover, multiplex emissions of the PLSN-probe illuminate different organelles such as the nucleus, nucleolemma, and cytoskeleton, depending on size-based preferential uptake by the cell organs. This in vitro study reveals that cancerous HeLa cells have a higher propensity for taking up the PLSN-probe compared to fibroblast cells, allowing the diagnosis of cancerous HeLa cells. Additionally, the fluorescence intensity per unit area of the cell is found to be a reliable means for distinguishing between dead and healthy cells. It is anticipated that the multifunctionality of the PLSN-probes will lead to better insight into the use of such probes for bioimaging and diagnosis applications.

Safety of Nonporous Silica Nanoparticles in Human Corneal Endothelial Cells

Nonporous silica nanoparticles (SiNPs) are promising drug carrier platforms for intraocular drug delivery. In this study, we investigated the safety of three different sizes of SiNPs (50, 100, and 150 nm) in a human corneal endothelial cell (HCEC) line, B4G12. The HCECs were exposed to different concentrations (0, 25, 50, and 100 µg/ml) of three sizes of SiNPs for up to 48 h. Cellular viability, autophagy, lactate dehydrogenase (LDH) assay, and mammalian target of rapamycin (mTOR) pathway activation were evaluated. Intracellular distribution of the SiNPs was evaluated with transmission electron microscopy (TEM). TEM revealed that the SiNPs were up-taken by the HCECs inside cytoplasmic vacuoles. No mitochondrial structural damage was observed. Both cellular viability and LDH level remained unchanged with up to 100 µg/mL of SiNP treatment. Autophagy showed a significant dose-dependent activation with 50, 100, and 150 nm SiNPs. However, the mTOR activation remained unchanged. Human corneal tissue culture with 100 µg/ml concentrations of SiNPs for 72 h revealed no significant endothelial toxicity. In vivo corneal safety of the SiNPs (0.05 ml intracameral injection, 200 mg/ml concentration) was also verified in rabbit models. These findings suggested that 50, 100, and 150 nm SiNPs did not induce acute significant cytotoxicity in corneal endothelial cells at concentrations up to 100 µg/mL. However, long-term toxicity of SiNPs remains unknown.

Exploring cellular uptake of iron oxide nanoparticles associated with rhodium citrate in breast cancer cells

Nanocarriers have the potential to improve the therapeutic index of currently available drugs by improving their efficacy and achieving therapeutic steady-state levels over an extended period. The association of maghemite-rhodium citrate (MRC) nanoparticles (NPs) has the potential to increase specificity of the cytotoxic action. However, the interaction of these NPs with cells, their uptake mechanism, and subcellular localization need to be elucidated. This work evaluates the uptake mechanism of MRC NPs in metastatic and nonmetastatic breast cancer-cell models, comparing them to a nontumor cell line. MRC NPs uptake in breast cancer cells was more effective than in normal cells, with regard to both the amount of internalized material and the achievement of more strategic intracellular distribution. Moreover, this process occurred through a clathrin-dependent endocytosis pathway with different basal expression levels of this protein in the cell lines tested.

In vitro biocompatibility study of sub-5 nm silica-coated magnetic iron oxide fluorescent nanoparticles for potential biomedical application

Magnetic iron oxide nanoparticles (IONPs), for their intriguing properties, have attracted a great interest as they can be employed in many different biomedical applications. In this multidisciplinary study, we synthetized and characterized ultrafine 3 nm superparamagnetic water-dispersible nanoparticles. By a facile and inexpensive one-pot approach, nanoparticles were coated with a shell of silica and contemporarily functionalized with fluorescein isothiocyanate (FITC) dye. The obtained sub-5 nm silica-coated magnetic iron oxide fluorescent (sub-5 SIO-Fl) nanoparticles were assayed for cellular uptake, biocompatibility and cytotoxicity in a human colon cancer cellular model. By confocal microscopy analysis we demonstrated that nanoparticles as-synthesized are internalized and do not interfere with the CaCo-2 cell cytoskeletal organization nor with their cellular adhesion. We assessed that they do not exhibit cytotoxicity, providing evidence that they do not affect shape, proliferation, cellular viability, cell cycle distribution and progression. We further demonstrated at molecular level that these nanoparticles do not interfere with the expression of key differentiation markers and do not affect pro-inflammatory cytokines response in Caco-2 cells. Overall, these results showed the in vitro biocompatibility of the sub-5 SIO-Fl nanoparticles promising their safe employ for diagnostic and therapeutic biomedical applications.

The shape effect of magnetic mesoporous silica nanoparticles on endocytosis, biocompatibility and biodistribution

Although the aspect ratio (AR) play a crucial role in determining biological effects of homogeneous nanomaterials, studies available concerning how the shape contributes to biological effect of heterogeneous nanomaterials is limited. To systematically clarify the shape influence on the endocytosis, biocompatibility and biodistribution of magnetic mesoporous silica nanoparticles (M-MSNPs), three FITC-labeled M-MSNPs with different aspect ratio (AR=1, 2, and 4) were specifically designed and constructed through altering the ratios of CTAB/TEOS in a modified so-gel method. We have demonstrated that long-rod M-MSNP2 possessed higher intracellular internalization amount than the short-rod M-MSNP1 and the sphere-like M-MSNP0 in both cancer cells and normal cells due to the difference in the endocytosis pathways. However, there are no significant shape effects on biocompatibility including cytotoxicity and hemolytic rate. Moreover, biodistribution in HepG2 tumor-bearing mice showed that M-MSNPs administrated intravenously were mainly presented in reticuloendothelial system (RES) organs including liver, spleen and kidney. In particular, sphere-like M-MSNP0 were easily trapped in the liver, while long-rod M-MSP2 exhibited more retention in the spleen. It is worth noting that rod-like M-MSNPs are preferentially accumulated in tumor sites than sphere-like M-MSNPs, indicating an improved drug delivery efficacy in cancer therapy. Our findings may provide useful data for deeply understanding the interaction between the different shapes and biological behavior of M-MSNPs, which is expected to give rise to a new generation of heterogeneous M-MSNPs with significantly enhanced efficacy and safety for the cancer theranostics.

STATEMENT OF SIGNIFICANCE

In this work, we systematically clarified the shape influence on the endocytosis, biocompatibility and biodistribution of homogeneous nanomaterials. We have demonstrated that rod-like magnetic mesoporous silica nanoparticles (M-MSNPs) were capable of higher intracellular internalization and tumor accumulation than sphere-like M-MSNPs, which was expected to give rise to a new generation of heterogeneous M-MSNPs with significantly enhanced efficacy and safety for the cancer theranostics.

Amorphous Silica Particles Relevant in Food Industry Influence Cellular Growth and Associated Signaling Pathways in Human Gastric Carcinoma Cells

Nanostructured silica particles are commonly used in biomedical and biotechnical fields, as well as, in cosmetics and food industry. Thus, their environmental and health impacts are of great interest and effects after oral uptake are only rarely investigated. In the present study, the toxicological effects of commercially available nano-scaled silica with a nominal primary diameter of 12 nm were investigated on the human gastric carcinoma cell line GXF251L. Besides the analysis of cytotoxic and proliferative effects and the comparison with effects of particles with a nominal primary diameter of 200 nm, emphasis was also given to their influence on the cellular epidermal growth factor receptor (EGFR) and mitogen-activated protein kinases (MAPK) signaling pathways—both of them deeply involved in the regulation of cellular processes like cell cycle progression, differentiation or proliferation. The investigated silica nanoparticles (NPs) were found to stimulate cell proliferation as measured by microscopy and the sulforhodamine B assay. In accordance, the nuclear level of the proliferation marker Ki-67 was enhanced in a concentration-dependent manner. At high particle concentrations also necrosis was induced. Finally, silica NPs affected the EGFR and MAPK pathways at various levels dependent on concentration and time. However, classical activation of the EGFR, to be reflected by enhanced levels of phosphorylation, could be excluded as major trigger of the proliferative stimulus. After 45 min of incubation the level of phosphorylated EGFR did not increase, whereas enhanced levels of total EGFR protein were observed. These results indicate interference with the complex homeostasis of the EGFR protein, whereby up to 24 h no impact on the transcription level was detected. In addition, downstream on the level of the MAP kinases ERK1/2 short term incubation appeared to affect total protein levels without clear increase in phosphorylation. Depending on the concentration range, enhanced levels of ERK1/2 phosphorylation were only observed after 24 h of incubation. Taken together, the present study demonstrates the potential of the tested silica particles to enhance the growth of gastric carcinoma cells. Although interference with the EGFR/MAPK cascade is observed, additional mechanisms are likely to be involved in the onset of the proliferative stimulus.

Insight into the interactions between nanoparticles and cells

This review summarizes the latest advances in nanoparticle (NP)–cell interactions. The influence of NP size, shape, shell structure, surface chemistry and protein corona formation on cellular uptake and cytotoxicity is highlighted in detail. Their impact on other cellular responses such as cell proliferation, differentiation and cellular mechanics is also discussed.

Formulation and In vitro Interaction of Rhodamine-B Loaded PLGA Nanoparticles with Cardiac Myocytes

This study aims to characterize rhodamine B (Rh B) loaded poly(D,L-lactide-co-glycolide; PLGA) nanoparticles (NPs) and their interactions with cardiac myocytes. PLGA NPs were formulated using single emulsion solvent evaporation technique. The influence of varying parameters such as the stabilizer concentration, the sonication time, and the organic to aqueous ratio were investigated. The diameter, the dispersity, the encapsulation efficiency and the zeta potential of the optimized NPs were about 184 nm, 0.19, 40% and -21.7 mV, respectively. In vitro release showed that 29% of the Rh B was released within the first 8 h. Scanning electron microscopy measurements performed on the optimized NPs showed smooth surface and spherical shapes. No significant cytotoxic or apoptotic effects were observed on cardiac myocytes after 24 and 48 h of exposure with concentrations up to 200 μg/mL. The kinetic of the intracellular uptake was confirmed by confocal microscopy and cells took up PLGA NPs within the 1st hours. Interestingly, our data show an increase in the NPs' uptake with time of exposure. Taken together, we demonstrate for the first time that the designed NPs can be used as potential probes for drug delivery in cardiac myocytes.

Cellular uptake and dynamics of unlabeled freestanding silicon nanowires

The ability to seamlessly merge electronic devices with biological systems at the cellular length scale is an exciting prospect for exploring new fundamental cell biology and in designing next-generation therapeutic devices. Semiconductor nanowires are well suited for achieving this goal because of their intrinsic size and wide range of possible configurations. However, current studies have focused primarily on delivering substrate-bound nanowire devices through mechanical abrasion or electroporation, with these bulkier substrates negating many of the inherent benefits of using nanoscale materials. To improve on this, an important next step is learning how to distribute these devices in a drug-like fashion, where cells can naturally uptake and incorporate these electronic components, allowing for truly noninvasive device integration. We show that silicon nanowires (SiNWs) can potentially be used as such a system, demonstrating that label-free SiNWs can be internalized in multiple cell lines (96% uptake rate), undergoing an active "burst-like" transport process. Our results show that, rather than through exogenous manipulation, SiNWs are internalized primarily through an endogenous phagocytosis pathway, allowing cellular integration of these materials. To study this behavior, we have developed a robust set of methodologies for quantitatively examining high-aspect ratio nanowire-cell interactions in a time-dependent manner on both single-cell and ensemble levels. This approach represents one of the first dynamic studies of semiconductor nanowire internalization and offers valuable insight into designing devices for biomolecule delivery, intracellular sensing, and photoresponsive therapies.