The interactions of single-wall carbon nanohorns with polar epithelium

Modeling the Cellular Uptake of Functionalized Carbon Nanohorns Loaded with Cisplatin through a Breast Cancer Cell Membrane

The cisplatin encapsulation into carbon nanohorns (CNH) is a promising nanoformulation to circumvent the drug dissipation and to specifically accumulate it in tumor sites. Herein, biased molecular dynamics simulations were used to analyze the transmembrane transport of the CNH loaded with cisplatin through a breast cancer cell membrane prototype. The simulations revealed a four-stage mechanism: approach, insertion, permeation, and internalization. Despite the lowest structural disturbance of the membrane provided by the nanocarrier, the average free energy barrier for the translocation was 55.2 kcal mol-1, suggesting that the passive process is kinetically unfavorable. In contrast, the free energy profiles revealed potential wells of -6.8 kcal mol-1 along the insertion stage in the polar heads region of the membrane, which might enhance the retention of the drug in tumor sites; therefore, the most likely cisplatin delivery mechanism should involve the adsorption and retention of CNH on the surface of cancer cells, allowing the loaded cisplatin be slowly released and passively transported through the cell membrane.

Green Approaches to Carbon Nanostructure-Based Biomaterials

The family of carbon nanostructures comprises several members, such as fullerenes, nano-onions, nanodots, nanodiamonds, nanohorns, nanotubes, and graphene-based materials. Their unique electronic properties have attracted great interest for their highly innovative potential in nanomedicine. However, their hydrophobic nature often requires organic solvents for their dispersibility and processing. In this review, we describe the green approaches that have been developed to produce and functionalize carbon nanomaterials for biomedical applications, with a special focus on the very latest reports.

Enhancement of Anticancer Efficacy and Tumor Penetration of Sorafenib by Ionic Liquids

Ionic liquids (ILs) possess unique solvation and biological properties for drug delivery. Choline and geranic acid (CAGE) in particular, has been successfully formulated to orally deliver insulin and hydrophobic therapeutics such as sorafenib (SRF). However, relatively little is known about the effect of CAGE on intracellular delivery of drugs. Here the effect of low-concentration CAGE (<2 mg mL^-1 ) on the delivery of SRF into cancer cells (4T1, PANC-1, and HT29) as well as intestine epithelium cells (Caco-2) is studied. The anti-cancer effect of SRF is enhanced by up to fivefold in the presence of CAGE (0.5 mg mL^-1 ). The effect is mediated not by enhancing the cellular uptake of SRF but by improving intracellular SRF retention by inhibiting exocytosis. Moreover, CAGE improves the anti-tumor effect of SRF by increasing apoptosis and blocking cell-cycle progression. Moreover, CAGE significantly enhances the penetration of SRF into and across multicellular constructs with multiple mechanisms involved. Collectively, the administration of ILs such as CAGE combined with SRF may offer a novel therapy to better inhibit tumor progression.

Investigation of the Cellular Destination of Fluorescently Labeled Carbon Nanohorns in Cultured Cells

The high surface area, facile functionalization, and biocompatibility of carbon nanohorns (CNHs) make them attractive for many applications, including drug delivery. The cellular destination of nanomaterials dictates both the therapeutic application and the potential toxicity. Identifying the uptake mechanism is challenging as several endocytic pathways have been identified that facilitate cellular entry. Here, the cellular uptake of fluorescently labeled CNHs was assessed by utilizing quantitative cell-based assays to determine the factors influencing how internalization occurs and the destinations they reach in HeLa cells. Cell viability assays suggest that about 80% of the cells remained viable even at the highest concentration of 20 μg/mL exposure to CNHs. Uptake studies revealed that when pulse-chase conditions were applied, CNHs were seen to be localized both at the cell periphery and in a juxtanuclear pattern inside HeLa cells, in the latter case colocalizing with the lysosomal marker LAMP1. RNA interference studies, using a panel of RNA tools to individually deplete key molecules associated with the endocytic machinery, failed to block the internalization of CNHs into cells, suggesting that multiple mechanisms of endocytosis are used by this particle type.

Single-Walled Carbon Nanohorns as Promising Nanotube-Derived Delivery Systems to Treat Cancer

Cancer has become one of the most prevalent diseases worldwide, with increasing incidence in recent years. Current pharmacological strategies are not tissue-specific therapies, which hampers their efficacy and results in toxicity in healthy organs. Carbon-based nanomaterials have emerged as promising nanoplatforms for the development of targeted delivery systems to treat diseased cells. Single-walled carbon nanohorns (SWCNH) are graphene-based horn-shaped nanostructure aggregates with a multitude of versatile features to be considered as suitable nanosystems for targeted drug delivery. They can be easily synthetized and functionalized to acquire the desired physicochemical characteristics, and no toxicological effects have been reported in vivo followed by their administration. This review focuses on the use of SWCNH as drug delivery systems for cancer therapy. Their main applications include their capacity to act as anticancer agents, their use as drug delivery systems for chemotherapeutics, photothermal and photodynamic therapy, gene therapy, and immunosensing. The structure, synthesis, and covalent and non-covalent functionalization of these nanoparticles is also discussed. Although SWCNH are in early preclinical research yet, these nanotube-derived nanostructures demonstrate an interesting versatility pointing them out as promising forthcoming drug delivery systems to target and treat cancer cells.

Cellular Responses of Human Lymphatic Endothelial Cells to Carbon Nanomaterials

One of the greatest challenges to overcome in the pursuit of the medical application of carbon nanomaterials (CNMs) is safety. Particularly, when considering the use of CNMs in drug delivery systems (DDSs), evaluation of safety at the accumulation site is an essential step. In this study, we evaluated the toxicity of carbon nanohorns (CNHs), which are potential DDSs, using human lymph node endothelial cells that have been reported to accumulate CNMs, as a comparison to fibrous, multi-walled carbon nanotubes (MWCNTs) and particulate carbon black (CB). The effect of different surface characteristics was also evaluated using two types of CNHs (untreated and oxidized). In the fibrous MWCNT, cell growth suppression, as well as expression of inflammatory cytokine genes was observed, as in previous reports. In contrast, no significant toxicity was observed for particulate CB and CNHs, which was different from the report of CB cytotoxicity in vascular endothelial cells. These results show that (1) lymph endothelial cells need to be tested separately from other endothelial cells for safety evaluation of nanomaterials, and (2) the potential of CNHs as DDSs.

The Nano-Intestine Interaction: Understanding the Location-Oriented Effects of Engineered Nanomaterials in the Intestine

Engineered nanomaterials (ENMs) are used in food additives, food packages, and therapeutic purposes owing to their useful properties, Therefore, human beings are orally exposed to exogenous nanomaterials frequently, which means the intestine is one of the primary targets of nanomaterials. Consequently, it is of great importance to understand the interaction between nanomaterials and the intestine. When nanomaterials enter into gut lumen, they inevitably interact with various components and thereby display different effects on the intestine based on their locations; these are known as location-oriented effects (LOE). The intestinal LOE confer a new biological-effect profile for nanomaterials, which is dependent on the involvement of the following biological processes: nano-mucus interaction, nano-intestinal epithelial cells (IECs) interaction, nano-immune interaction, and nano-microbiota interaction. A deep understanding of NM-induced LOE will facilitate the design of safer NMs and the development of more efficient nanomedicine for intestine-related diseases. Herein, recent progress in this field is reviewed in order to better understand the LOE of nanomaterials. The distant effects of nanomaterials coupling with microbiota are also highlighted. Investigation of the interaction of nanomaterials with the intestine will stimulate other new research areas beyond intestinal nanotoxicity.

Biodistribution Survey of Oxidized Single-Wall Carbon Nanohorns Following Different Administration Routes by Using Label-Free Multispectral Optoacoustic Tomography

Introduction

Though widely studied for biomedical applications, the lack of current systemic studies on the in vivo fate of single-walled carbon nanohorns (SWCNHs) largely restricts their further applications, as real-time monitoring of their biodistribution remains a big challenge. Here, we aim to customize a label-free multispectral optoacoustic tomography (MSOT) method and systematically survey the fate of oxidized SWCNHs (SWCNHox) following different exposure routes by whole body imaging.

Methods

Mice were given a suspension of SWCNHox with an average size of 136.4 nm via four different administration routes, and then imaged by MSOT.

Results

After oral gavage, SWCNHox were mainly distributed in the gastrointestinal tract then excreted through the gut. Compared with the observation post first dosing, the accumulation of SWCNHox in the gastrointestinal tract was not obvious even after four-time oral gavage. Almost no SWCNHox were found at detectable levels in kidney, liver, blood and spleen. Following intravenous (iv) injection, SWCNHox were mainly presented and persisted in the spleen and liver, while very little in the kidney and almost none detectable in the intestine. SWCNHox accumulated significantly in the liver and spleen after four IV administrations. Following hypodermic and intramuscular injections, almost no SWCNHox could cross biological barriers and transport to the spleen, kidney or liver, likely due to their very low absorption rate. Almost all SWCNHox remained around the injection sites. For the first time, we have systematically investigated the in vivo fate of SWCNHs in a label-free and real-time manner.

Conclusion

The findings of this study provide insights into the selection of appropriate exposure routes for potential biomedical applications of carbon nanomaterials.

Single-walled carbon-nanohorns improve biocompatibility over nanotubes by triggering less protein-initiated pyroptosis and apoptosis in macrophages

Single-walled carbon-nanohorns (SNH) exhibit huge application prospects. Notably, spherical SNH possess different morphology from conventional carbon nanotubes (CNT). However, there is a tremendous lack of studies on the nanotoxicity and mechanism of SNH, and their comparison with nanotubes. Here, the dissimilarity between SNH and CNT is found in many aspects including necrosis, pyroptosis, apoptosis, protein expression, hydrolases leakage, lysosome stress, membrane disturbance and the interaction with membrane proteins. The improved biocompatibility of SNH over four types of established CNT is clearly demonstrated in macrophages. Importantly, a key transmembrane protein, glycoprotein nonmetastatic melanoma protein B (GPNMB) is discovered to initiate the nanotoxicity. Compared to CNT, the weaker nano-GPNMB interaction in SNH group induces lower degree of cascade actions from nano/membrane interplay to final cell hypotoxicity. In conclusion, the geometry of single-construct unit, but not that of dispersive forms or intracellular levels of nanocarbons make the most difference.