Biosafety of Non-Surface Modified Carbon Nanocapsules as a Potential Alternative to Carbon Nanotubes for Drug Delivery Purposes

BACKGROUND: Carbon nanotubes (CNTs) have found wide success in circuitry, photovoltaics, and other applications. In contrast, several hurdles exist in using CNTs towards applications in drug delivery. Raw, non-modified CNTs are widely known for their toxicity. As such, many have attempted to reduce CNT toxicity for intravenous drug delivery purposes by post-process surface modification. Alternatively, a novel sphere-like carbon nanocapsule (CNC) developed by the arc-discharge method holds similar electric and thermal conductivities, as well as high strength. This study investigated the systemic toxicity and biocompatibility of different non-surface modified carbon nanomaterials in mice, including multi-walled carbon nanotubes (MWCNTs), single-walled carbon nanotubes (SWCNTs), carbon nanocapsules (CNCs), and C ₆₀ fullerene (C ₆₀). The retention of the nanomaterials and systemic effects after intravenous injections were studied. METHODOLOGY AND PRINCIPAL FINDINGS: MWCNTs, SWCNTs, CNCs, and C ₆₀ were injected intravenously into FVB mice and then sacrificed for tissue section examination. Inflammatory cytokine levels were evaluated with ELISA. Mice receiving injection of MWCNTs or SWCNTs at 50 µg/g b.w. died while C ₆₀ injected group survived at a 50% rate. Surprisingly, mortality rate of mice injected with CNCs was only at 10%. Tissue sections revealed that most carbon nanomaterials retained in the lung. Furthermore, serum and lung-tissue cytokine levels did not reveal any inflammatory response compared to those in mice receiving normal saline injection. CONCLUSION: Carbon nanocapsules are more biocompatible than other carbon nanomaterials and are more suitable for intravenous drug delivery. These results indicate potential biomedical use of non-surface modified carbon allotrope. Additionally, functionalization of the carbon nanocapsules could further enhance dispersion and biocompatibility for intravenous injection

Track A Basic Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd

Comprehensive molecular characterization of gastric adenocarcinoma

Gastric cancer is a leading cause of cancer deaths, but analysis of its molecular and clinical characteristics has been complicated by histological and aetiological heterogeneity. Here we describe a comprehensive molecular evaluation of 295 primary gastric adenocarcinomas as part of The Cancer Genome Atlas (TCGA) project. We propose a molecular classification dividing gastric cancer into four subtypes: tumours positive for Epstein–Barr virus, which display recurrent PIK3CA mutations, extreme DNA hypermethylation, and amplification of JAK2, CD274 (also known as PD-L1) and PDCD1LG2 (also knownasPD-L2); microsatellite unstable tumours, which show elevated mutation rates, including mutations of genes encoding targetable oncogenic signalling proteins; genomically stable tumours, which are enriched for the diffuse histological variant and mutations of RHOA or fusions involving RHO-family GTPase-activating proteins; and tumours with chromosomal instability, which show marked aneuploidy and focal amplification of receptor tyrosine kinases. Identification of these subtypes provides a roadmap for patient stratification and trials of targeted therapies

Multiplatform Analysis of 12 Cancer Types Reveals Molecular Classification within and across Tissues of Origin

Recent genomic analyses of pathologically-defined tumor types identify “within-a-tissue” disease subtypes. However, the extent to which genomic signatures are shared across tissues is still unclear. We performed an integrative analysis using five genome-wide platforms and one proteomic platform on 3,527 specimens from 12 cancer types, revealing a unified classification into 11 major subtypes. Five subtypes were nearly identical to their tissue-of-origin counterparts, but several distinct cancer types were found to converge into common subtypes. Lung squamous, head & neck, and a subset of bladder cancers coalesced into one subtype typified by TP53 alterations, TP63 amplifications, and high expression of immune and proliferation pathway genes. Of note, bladder cancers split into three pan-cancer subtypes. The multi-platform classification, while correlated with tissue-of-origin, provides independent information for predicting clinical outcomes. All datasets are available for data-mining from a unified resource to support further biological discoveries and insights into novel therapeutic strategies

Treatment of Acute Thromboembolism in Mice Using Heparin-Conjugated Carbon Nanocapsules

The unsurpassed properties in electrical conductivity, thermal conductivity, strength, and surface area-to-volume ratio allow for many potential applications of carbon nanomaterials in various fields. Recently, studies have characterized the potential of using carbon nanotubes (CNTs) as a biomaterial for biomedical applications and as a drug carrier <i>via</i> intravenous injection. However, most studies show that unmodified CNTs possess a high degree of toxicity and cause inflammation, mechanical obstruction from high organ retention, and other biocompatibility issues following <i>in vivo</i> delivery. In contrast, carbon nanocapsules (CNCs) have a lower aspect ratio compared with CNTs and have a higher dispersion rate. To investigate the possibility of using CNCs as an alternative to CNTs for drug delivery, heparin-conjugated CNCs (CNC-H) were studied in a mouse model of acute hindlimb thromboembolism. Our results showed that CNC-H not only displayed superior antithrombotic activity <i>in vitro</i> and <i>in vivo</i> but they also had the ability to extend the thrombus formation time far longer than an injection of heparin or CNCs alone. Therefore, the present study showed for the first time that functionalized CNCs can act as nanocarriers to deliver thrombolytic therapeutics

Carbon nanomaterial retention in the lungs.

<p>(<b>A</b>) Lung tissue sections of mice 7 days after intravenous injection with carbon nanomaterials at 25 μg/g b.w. (<b>B</b>) Automatic carbon nanomaterial retention quantification in the lungs. High-magnification images (red-bordered images) show large carbon nanotube aggregates blocking the blood vessels of the lungs (arrows). SWCNTs and MWCNTs were retained in the lungs at much higher rates compared to CNCs or C₆₀. Tissue sections were stained with hematoxylin. Scale bar = 100 μm. ***<i>P</i><0.0001 compared to CNCs and C₆₀, n = 4 in all groups. NS, normal saline; PVA, polyvinyl alcohol; CNCs, carbon nanocapsules; C₆₀, C₆₀ fullerene; MWCNTs, multi-walled carbon nanotubes; SWCNTs, single-walled carbon nanotubes.</p

Systemic inflammatory cytokine level in mice.

<p>Serum and lung tissue IL-1β and IL-6 levels 6 hours post-injection with carbon nanomaterials. There is no significant difference between all groups (except LPS). n = 5, <i>P</i> = 0.0029 (serum, IL-1β); n = 5, <i>P</i> = 0.0001 (serum, IL-6); n = 4. *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001 significantly different compared with the LPS group. NS, normal saline; PVA, polyvinyl alcohol; CNCs, carbon nanocapsules; C₆₀, C₆₀ fullerene; M, multi-walled carbon nanotubes; S, single-walled carbon nanotubes.</p

Mouse survival curves after carbon nanomaterial injection.

<p>(<b>A</b>) TEM analysis of carbon nanocapsules (CNCs), C₆₀ fullerene (C₆₀), multi-walled carbon nanotubes (MWCNTs), and single-walled carbon nanotubes (SWCNTs) dispersed in 1% polyvinyl alcohol (PVA). SWCNTs formed large networks, and MWCNTs aggregated compactly. CNCs were well dispersed in PVA, while C₆₀ aggregated to size as large as CNCs. The scale bar is 100<b> </b>nm. (<b>B</b>) Cumulative deaths of mice intravenously injected with different doses of carbon nanomaterials. SWCNTs and MWCNTs had the highest toxicity, which was dose dependent, decreasing as the dose of the carbon nanomaterials decreased. No mortality was observed among the CNC-treated mice at 25 μg/g b.w. n = 12 for CNC, and C₆₀ injected mice. n = 11 for NS, PVA, MWCNT, and SWCNT injected mice. Red square, 50 μg/g; black dot, 25 μg/g; black cross, 12.5 μg/g.</p

Carbon nanomaterial retention in vital organs.

<p>Liver, spleen, and kidney tissue sections of mice 7 days after intravenous injection with carbon nanomaterials at 25 μg/g b.w. Carbon nanomaterials are indicated by arrows. Tissue sections were stained with hematoxylin. The scale bar is 50 μm. PVA, polyvinyl alcohol; CNCs, carbon nanocapsules; C₆₀, C₆₀ fullerene; MWCNTs, multi-walled carbon nanotubes; SWCNTs, single-walled carbon nanotubes.</p

Lung tissue inflammatory cytokine level in mice.

<p>Lung tissue IL-1β and IL-6 levels 6 hours post-injection with carbon nanomaterials. There is no significant difference between all groups (except LPS). Lung-tissue cytokine levels were normalized to the total protein level determined using a BCA kit (Pierce, USA). n = 5, ***<i>P</i> = 0.0001 (lung tissue, IL-1β); n = 4, <i>P</i> = 0.0001 (lung tissue, IL-6), compared to the LPS group. NS, normal saline; PVA, polyvinyl alcohol; CNCs, carbon nanocapsules; C₆₀, C₆₀ fullerene; M, multi-walled carbon nanotubes; S, single-walled carbon nanotubes.</p