Delivery of small interfering RNAs in human cervical cancer cells by polyethylenimine-functionalized carbon nanotubes

Effect of boramidic acid modified carbon nanotubes on neurological, morphological and physiological responses of zebrafish (Danio rerio) embryos and larvae

This study aimed to determine the potential toxicological effects of carbon nanotubes (CNTs), their modifications with ethylenediamine (ED) and boric acid (BA) on aquatic organisms. Specifically, the research focused on the morphological, physiological, and histopathological-immuno-histochemical responses in zebrafish (Danio rerio) embryos and larvae, via applying different concentrations of CNTs, CNT-ED, and CNT-ED-BA (Control, 5, 10, and 20 mg/L). The results indicated that 20 mg/L CNT nanoparticles were toxic to zebrafish larvae, with mortality rates increasing with CNT and CNT-ED concentrations, reaching 36.7 % at the highest CNT concentration. The highest dose caused considerable degeneration, necrosis, DNA damage, and apoptosis, as evidenced by histopathological and immunohistochemical tests. In contrast, despite their high concentration, CNT-ED-BA nanoparticles exhibited low toxicity. Behavioral studies revealed that CNT and CNT-ED nanoparticles had a more significant impact on sensory-motor functions compared to CNT-ED-BA nanoparticles. These findings suggest that modifying the nanosurface with boric acid, resulting in boramidic acid, can reduce the toxicity induced by CNT and CNT-ED.

Current development of theragnostic nanoparticles for women's cancer treatment

In the biomedical industry, nanoparticles (NPs-exclusively small particles with size ranging from 1-100 nanometres) are recently employed as powerful tools due to their huge potential in sophisticated and enhanced cancer theragnostic (i.e. therapeutics and diagnostics). Cancer is a life-threatening disease caused by carcinogenic agents and mutation in cells, leading to uncontrolled cell growth and harming the body's normal functioning while affecting several factors like low levels of reactive oxygen species, hyperactive antiapoptotic mRNA expression, reduced proapoptotic mRNA expression, damaged DNA repair, and so on. NPs are extensively used in early cancer diagnosis and are functionalized to target receptors overexpressing cancer cells for effective cancer treatment. This review focuses explicitly on how NPs alone and combined with imaging techniques and advanced treatment techniques have been researched against 'women's cancer' such as breast, ovarian, and cervical cancer which are substantially occurring in women. NPs, in combination with numerous imaging techniques (like PET, SPECT, MRI, etc) have been widely explored for cancer imaging and understanding tumor characteristics. Moreover, NPs in combination with various advanced cancer therapeutics (like magnetic hyperthermia, pH responsiveness, photothermal therapy, etc), have been stated to be more targeted and effective therapeutic strategies with negligible side effects. Furthermore, this review will further help to improve treatment outcomes and patient quality of life based on the theragnostic application-based studies of NPs in women's cancer treatment.

Unlocking the potential of nanocarrier-mediated mRNA delivery across diverse biomedical frontiers: A comprehensive review

Messenger RNA (mRNA) has gained marvelous attention for managing and preventing various conditions like cancer, Alzheimer's, infectious diseases, etc. Due to the quick development and success of the COVID-19 mRNA-based vaccines, mRNA has recently grown in prominence. A lot of products are in clinical trials and some are already FDA-approved. However, still improvements in line of optimizing stability and delivery, reducing immunogenicity, increasing efficiency, expanding therapeutic applications, scalability and manufacturing, and long-term safety monitoring are needed. The delivery of mRNA via a nanocarrier system gives a synergistic outcome for managing chronic and complicated conditions. The modified nanocarrier-loaded mRNA has excellent potential as a therapeutic strategy. This emerging platform covers a wide range of diseases, recently, several clinical studies are ongoing and numerous publications are coming out every year. Still, many unexplained physical, biological, and technical problems of mRNA for safer human consumption. These complications were addressed with various nanocarrier formulations. This review systematically summarizes the solved problems and applications of nanocarrier-based mRNA delivery. The modified nanocarrier mRNA meaningfully improved mRNA stability and abridged its immunogenicity issues. Furthermore, several strategies were discussed that can be an effective solution in the future for managing complicated diseases.

Production of Stable Electrically Conductive PVDF Membranes Based on Polydopamine-Polyethyleneimine-Assisted Deposition of Carbon Nanotubes

Electrically conductive membranes (ECMs) have emerged as a multifunctional separation technology that integrates membrane filtration with electrochemical reactions. Physical stability remains a critical challenge for ECMs synthesized by coating polymer membranes with conductive materials. In this article, polydopamine (PDA) and polyethyleneimine (PEI) were used to facilitate the synthesis of significantly more stable ECMs using poly(vinylidene fluoride) (PVDF) ultrafiltration membranes and carbon nanotubes (CNTs). Four different synthesis methods were compared in terms of the final surface stability and separation properties: (1) CNTs deposited on PEI-crosslinked PDA-coated PVDF membranes, (2) PEI-crosslinked CNTs deposited on PDA-coated PVDF, (3) PDA, PEI and CNTs sequentially deposited layer-by-layer on PVDF, and (4) PEI-crosslinked PDA deposited on CNT-coated PVDF. The results revealed that method 1 generated ECMs with the greatest physical stability, highest electrical conductivity (18,518 S/m), and sufficient permeability (395.2 L/(m2·h·bar). In comparison, method 2 resulted in membranes with the highest permeability (2128.5 L/(m2·h·bar), but with low surface conductivity (502 S/m) and poor physical stability (i.e., 53-75% lower peel-off forces compared to other methods). Overall, methods 1, 3, and 4 can be used to make highly conductive membranes with a 97-99% removal of methyl orange by electrochemical degradation at -3 V.

Molecular dynamics investigation on synthesis of a pH- and temperature-sensitive carbon nanotube loaded with doxorubicin

The many exotic properties of carbon nanotubes (CNTs) make them a powerful attraction in the field of drug delivery systems (DDS). In this work, based on quantum chemical calculation and molecular simulation techniques, polyacrylic acid (PAA) and N-isopropyl acrylamide (NIP) are selected and acted simultaneously on the CNT to form a stable system (FCNT). As a potential DDS, FCNT captures the dispersed doxorubicin (DOX) molecules around it and maintains a stable configuration. In these processes, electrostatic and van der Waals forces act synergistically, with van der Waals forces dominating. Compared to NIP, PAA molecules exhibit stronger adhesion and encapsulation efficiency to CNT and stronger adsorption capacity to DOX. This study reveals the mechanism of action among PAA, NIP, CNT, and DOX, providing feasibility verification and prospective guidance for the experimental synthesis of PAA-NIP-CNT-type multifunctional DDS, and also broadening the idea for exploring more efficient DDS suitable for DOX.

Design and synthesis of multi-targeted nanoparticles for gene delivery to breast cancer tissues

Biocompatibility of nanoparticles is the most essential factor in their use in clinical applications. In this study, hyperbranched spermine (HS), hyperbranched spermine-polyethylene glycol-folic acid (HSPF), and hyperbranched spermine-polyethylene glycol-glucose (HSPG) were synthesized for DNA protection and gene delivery to breast cancer cells. The synthesis of HSPG and HSPF was confirmed using proton nuclear magnetic resonance (H-NMR), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) spectroscopy. The HS/DNA, HSPF/DNA, HSPG/DNA, and hyperbranched spermine-polyethylene glycol-folic acid/glucose/DNA (HSPFG/DNA) nanoparticles were prepared by combining different concentrations of HS, HSPF, and HSPG with the same amount of DNA. The ability of HS, HSPF, and HSPG to interact with DNA and protect it against plasm digestion was evaluated using agarose gel. Moreover, in vivo and in vitro biocompatibility of HSPF/DNA, HSPG/DNA, and HSPFG/DNA was investigated using MTT assay and calculating weight change and survival ratio of BALB/c mice, respectively. The results of agarose gel electrophoresis showed that HS, HSPF, and HSPG have the high ability to neutralize the negative charge of DNA and protect it against plasma degradation. The results of in vivo cytotoxicity assay revealed that the HSPF/DNA, HSPG/DNA, and HSPFG/DNA nanoparticles have good biocompatibility on female BALB/c mice. In vitro and in vivo transfection assays revealed that functionalization of the surface of HS using polyethylene glycol-folic acid (HSPF) and polyethylene glycol-glucose (HSPG) significantly increases gene delivery efficiency in vitro and in vivo. These results also showed that gene transfer using both HSPF and HSPG copolymers increases gene transfer efficiency compared to when only one of them is used. The HSPFG/DNA nanoparticles have a high potential for use in therapeutic applications because of their excellent biocompatibility and high gene transfer efficiency to breast cancer tissue.

Carbon-based Nanomaterials for delivery of small RNA molecules: a focus on potential cancer treatment applications

BACKGROUND

Nucleic acid-mediated therapy holds immense potential in the treatment of recalcitrant human diseases such as cancer. This is underscored by advances in understanding the mechanisms of gene regulation. In particular, the endogenous protective mechanism of gene silencing known as RNA interference (RNAi) has been extensively exploited.

METHODS

We review here the developments from 2011 to 2021, in the use of nanographene oxide, carbon nanotubes, fullerenes, carbon nanohorns, carbon nanodots and nanodiamonds for the delivery of therapeutic small RNA molecules.

RESULTS

Appropriately designed effector molecules such as small interfering RNA (siRNA), can, in theory, silence the expression of any disease-causing gene. Alternatively, siRNA can be generated in vivo through the introduction of plasmid-based short hairpin RNA (shRNA) expression vectors. Other small RNAs such as micro RNA (miRNA) also function in post-transcriptional gene regulation and are aberrantly expressed under disease conditions. The miRNA-based therapy involves either restoration of miRNA function through the introduction of miRNA mimics; or the inhibition of miRNA function by delivering anti-miRNA oligomers. However, the large size, hydrophilicity, negative charge and nuclease-sensitivity of nucleic acids necessitate an appropriate carrier for their introduction as medicine into cells.

CONCLUSION

While numerous organic and inorganic materials have been investigated for this purpose, the perfect carrier agent remains elusive. In recent years, carbon-based nanomaterials have received widespread attention in biotechnology due to their tunable surface characteristics, mechanical, electrical, optical and chemical properties.

Insights on functionalized carbon nanotubes for cancer theranostics

Despite the exciting breakthroughs in medical technology, cancer still accounts for one of the principle triggers of death and conventional therapeutic modalities often fail to attain an effective cure. Recently, nanobiotechnology has made huge advancement in cancer therapy with gigantic application potential because of their ability in achieving precise and controlled drug release, elevating drug solubility and reducing adverse effects. Carbon nanotubes (CNTs), one of the most promising carbon-related nanomaterials, have already achieved much success in biomedical field. Due to their excellent optical property, thermal and electronic conductivity, easy functionalization ability and high drug loading capacity, CNTs can be applied in a multifunctional way for cancer treatment and diagnosis. In this review, we will give an overview of the recent progress of CNT-based drug delivery systems in cancer theranostics, which emphasizes their targetability to intracellular components of tumor cells and extracellular elements in tumor microenvironment. Moreover, a detailed introduction on how CNTs penetrate inside the tumor cells to reach their sites of action and achieve the therapeutic effects, as well as their diagnostic applications will be highlighted.

Photoactivatable nanoCRISPR/Cas9 System Based on crRNA Reversibly Immobilized on Carbon Nanoparticles

Here, we proposed a new approach to engineering a photoactivatable CRISPR/Cas9 gene-editing system. The novel nanoCRISPR/Cas9 system is based on the use of auxiliary photocleavable oligodeoxyribonucleotides (PC-DNAs) complementary to crRNA. PC-DNAs contained up to three UV-sensitive linkers made of 1-(2-nitrophenyl)-1,2-ethanediol inside the oligonucleotide chain. Immobilizing PC-DNAs on the surface of carbon nanoparticles through 3′-terminal pyrene residue provided sufficient blocking of crRNA (and corresponding Cas9 activity) before UV irradiation and allows for crRNA release after UV irradiation at 365 nm, which restores Cas9 activity. We optimized the length of blocking photocleavable oligonucleotide, number of linkers, time of irradiation, and the type of carbon nanoparticles. Based on the results, we consider the nanoCRISPR/Cas9 system involving carbon-encapsulated iron nanoparticles the most promising. It provides the greatest difference of functional activity before/after irradiation and can be used in prospective for magnetic field-controlled delivery of CRISPR system into the target cells or tissues and spatiotemporal gene editing induced by UV irradiation.

Tailoring the Architecture of Cationic Polymer Brush-Modified Carbon Nanotubes for Efficient siRNA Delivery in Cancer Immunotherapy

The facile and controlled fabrication of homogeneously grafted cationic polymers on carbon nanotubes (CNTs) remains poorly investigated, which further hinders the understanding of interactions between functionalized CNTs with different nucleic acids and the rational design of appropriate gene delivery vehicles. Herein, we describe the controlled grafting of cationic poly(2-dimethylaminoethylmethacrylate) brushes on CNTs via surface-initiated atom transfer radical polymerization integrated with mussel-inspired polydopamine chemistry. The binding of nucleic acids with different brush-CNT hybrids discloses the highly architectural-dependent behavior with dense short brush-coated CNTs displaying the highest binding among all the other hybrids, namely, dense long, sparse long, and sparse short brush-coated CNTs. Additionally, different chemistries of the brush coatings were shown to influence the biocompatibility, cellular uptake, and silencing efficiency in vitro. This platform provides great flexibility for the design of polymer brush-CNT hybrids with precise control over their structure-activity relationship for the rational design of nucleic acid delivery systems.

An Overview of Antimicrobial Properties of Carbon Nanotubes-Based Nanocomposites

The development of carbon-based nanomaterials has extensively facilitated new discoveries in various fields. Carbon nanotube-based nanocomposites (CNT-based nanocomposites) have lately recognized as promising biomaterials for a wide range of biomedical applications due to their unique electronic, mechanical, and biological properties. Nanocomposite materials such as silver nanoparticles (AgNPs), polymers, biomolecules, enzymes, and peptides have been reported in many studies, possess a broad range of antibacterial activity when incorporated with carbon nanotubes (CNTs). It is crucial to understand the mechanism which governs the antimicrobial activity of these CNT-based nanocomposite materials, including the decoupling individual and synergistic effects on the cells. In this review, the interaction behavior between microorganisms and different types of CNT-based nanocomposites is summarized to understand the respective antimicrobial performance in different conditions. Besides, the current development stage of CNT-based nanocomposite materials, the technical challenges faced, and the exceptional prospect of implementing potential antimicrobial CNT-based nanocomposite materials are also discussed.

Straightforward preparation of highly loaded MWCNT-polyamine hybrids and their application in catalysis

Multiwalled carbon nanotubes (MWCNTs) were easily and efficiently functionalised with highly cross-linked polyamines. The radical polymerisation of two bis-vinylimidazolium salts in the presence of pristine MWCNTs and azobisisobutyronitrile (AIBN) as a radical initiator led to the formation of materials with a high functionalisation degree. The subsequent treatment with sodium borohydride gave rise to the reduction of imidazolium moieties with the concomitant formation of secondary and tertiary amino groups. The obtained materials were characterised by thermogravimetric analysis (TGA), elemental analysis, solid state ¹³C-NMR, Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), potentiometric titration, and temperature programmed desorption of carbon dioxide (CO₂-TPD). One of the prepared materials was tested as a heterogeneous base catalyst in C-C bond forming reactions such as the Knoevenagel condensation and Henry reaction. Furthermore, two examples concerning a sequential one-pot approach involving two consecutive reactions, namely Knoevenagel and Michael reactions, were reported.

Carbon Nanospheres Exert Antitumor Effects Associated with Downregulation of 4E-BP1 Expression on Prostate Cancer

Introduction

Although carbon nanospheres (CNPs) are promising nanomaterials in cancer treatment, how they affect prostate cancer (PCa) remains unclear.

Methods

In this study, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy were used to confirm the successful synthesis of CNPs. CCK-8, flow cytometry, Transwell, wound healing, Western blot and immunohistochemistry (IHC) assays were performed to evaluate the antitumor effect of CNPs toward the two kinds of prostate cancer cell lines PC3 and DU145.

Results

Our results showed that CNPs inhibited cell growth, invasion, and migration and induced apoptosis and autophagy in PCa cells. Multifactor detection of a single Akt phosphorylation pathway and Western blot results suggested the suppression of 4E-BP1 in PCa cells after incubation with CNPs. The results from animal experiments also suggested the antitumor effect of CNPs and reduced 4E-BP1 expression in PCa tissue samples from BALB/c nude mice administered a local subcutaneous injection of CNPs.

A Review of Theranostics Applications and Toxicities of Carbon Nanomaterials

BACKGROUND

In the last few years, the use of modified Carbon Nanomaterials (CNMs) for theranostics (therapeutic and diagnosis) applications is a new and rapidly growing area in pharmacy and medical fields. Owing to this, their specific physicochemical behaviors like high stability, drug loading, surface area to volume ratio, with low toxicity and immunogenicity are mainly responsible to be considered those as smart nanomaterials.

OBJECTIVES

This review describes the different dimensions of carbon-based nanocarriers including 0-D fullerene, 1-D Carbon Nanotubes (CNTs), and 2-D graphene and Graphene Oxide (GO) and their surface modification with different biocompatible and biodegradable molecules via covalent or non-covalent functionalization. The major focus of this article is on the different theranostics applications of CNMs like targeted drugs and genes delivery, photodynamic therapy, photothermal therapy, bioimaging, and biosensing. The therapeutic efficacy of drugs could be enhanced by delivering them directly on a specific site using different targeted ligands such as vitamins, peptide, carbohydrates, proteins, etc. A section of the article also discusses the toxicity of the CNMs to the living systems.

CONCLUSIONS

In brief, this review article discusses the numerous theranostics applications and toxicities of CNMs.

Hyperthermia-Triggered Doxorubicin Release from Polymer-Coated Magnetic Nanorods

In this paper, it is proposed that polymer-coated magnetic nanorods (MNRs) can be used with the advantage of a double objective: first, to serve as magnetic hyperthermia agents, and second, to be used as magnetic vehicles for the antitumor drug doxorubicin (DOX). Two different synthetic methodologies (hydrothermal and co-precipitation) were used to obtain MNRs of maghemite and magnetite. They were coated with poly(ethyleneimine) and poly(sodium 4-styrenesulfonate), and loaded with DOX, using the Layer-by-Layer technique. Evidence of the polymer coating and the drug loading was justified by ATR-FTIR and electrophoretic mobility measurements, and the composition of the coated nanorods was obtained by a thermogravimetric analysis. The nanorods were tested as magnetic hyperthermia agents, and it was found that they provided sufficiently large heating rates to be used as adjuvant therapy against solid tumors. DOX loading and release were determined by UV-visible spectroscopy, and it was found that up to 50% of the loaded drug was released in about 5 h, although the rate of release could be regulated by simultaneous application of hyperthermia, which acts as a sort of external release-trigger. Shape control offers another physical property of the particles as candidates to interact with tumor cells, and particles that are not too elongated can easily find their way through the cell membrane.

Biomedical applications of carbon nanomaterials: Drug and gene delivery potentials

One of the major components in the development of nanomedicines is the choice of the right biomaterial, which notably determines the subsequent biological responses. The popularity of carbon nanomaterials (CNMs) has been on the rise due to their numerous applications in the fields of drug delivery, bioimaging, tissue engineering, and biosensing. Owing to their considerably high surface area, multifunctional surface chemistry, and excellent optical activity, novel functionalized CNMs possess efficient drug-loading capacity, biocompatibility, and lack of immunogenicity. Over the past few decades, several advances have been made on the functionalization of CNMs to minimize their health concerns and enhance their biosafety. Recent evidence has also implied that CNMs can be functionalized with bioactive peptides, proteins, nucleic acids, and drugs to achieve composites with remarkably low toxicity and high pharmaceutical efficiency. This review focuses on the three main classes of CNMs, including fullerenes, graphenes, and carbon nanotubes, and their recent biomedical applications.

Incorporation of Levodopa into Biopolymer Coatings Based on Carboxylated Carbon Nanotubes for pH-Dependent Sustained Release Drug Delivery

Four drug delivery systems were formulated by non-covalent functionalization of carboxylated single walled carbon nanotubes using biocompatible polymers as coating agent (i.e., Tween 20, Tween 80, chitosan or polyethylene glycol) for the delivery of levodopa, a drug used in Parkinson’s disease. The chemical interaction between the coating agent and carbon nanotubes-levodopa conjugate was confirmed by Fourier transform infrared (FTIR) and Raman studies. The drug release profiles were revealed to be dependent upon the type of applied coating material and this could be further adjusted to a desired rate to meet different biomedical conditions. In vitro drug release experiments measured using UV-Vis spectrometry demonstrated that the coated conjugates yielded a more prolonged and sustained release pattern compared to the uncoated conjugate. Cytotoxicity of the formulated conjugates was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using normal mouse embryonic fibroblast 3T3 cell line. Compared to the non-coated conjugate, the MTT data indicated that the coating procedure improved the biocompatibility of all systems by 34–41% when the concentration used exceeded 100 μg/mL. In conclusion, the comprehensive results of this study suggest that carbon nanotubes-based drug carrier coated with a suitable biomaterial may possibly be a potential nanoparticle system that could facilitate drug delivery to the brain with tunable physicochemical properties.

Biophysical and biological contributions of polyamine-coated carbon nanotubes and bidimensional buckypapers in the delivery of miRNAs to human cells

Recent findings in nanomedicine have revealed that carbon nanotubes (CNTs) can be used as potential drug carriers, therapeutic agents and diagnostics tools. Moreover, due to their ability to cross cellular membranes, their nanosize dimension, high surface area and relatively good biocompatibility, CNTs have also been employed as a novel gene delivery vector system. In our previous work, we functionalized CNTs with two polyamine polymers, polyethyleneimine (PEI) and polyamidoamine dendrimer (PAMAM). These compounds have low cytotoxicity, ability to conjugate microRNAs (such as miR-503) and, at the same time, transfect efficiently endothelial cells. The parameters contributing to the good efficiency of transfection that we observed were not investigated in detail. In fact, the diameter and length of CNTs are important parameters to be taken into account when evaluating the effects on drug delivery efficiency. In order to investigate the biophysical and biological contributions of polymer-coated CNTs in delivery of miRNAs to human cells, we decided to investigate three different preparations, characterized by different dimensions and aspect ratios. In particular, we took into account very small CNTs, a suspension of CNTs starting from the commercial product and a 2D material based on CNTs (ie, buckypapers [BPs]) to examine the transfection efficiency of a rigid scaffold. In conclusion, we extensively investigated the biophysical and biological contributions of polyamine-coated CNTs and bidimensional BPs in the delivery of miRNAs to human cells, in order to optimize the transfection efficiency of these compounds to be employed as efficient drug delivery vectors in biomedical applications.

Biophysical and biological contributions of polyamine-coated carbon nanotubes and bidimensional buckypapers in the delivery of miRNAs to human cells

Recent findings in nanomedicine have revealed that carbon nanotubes (CNTs) can be used as potential drug carriers, therapeutic agents and diagnostics tools. Moreover, due to their ability to cross cellular membranes, their nanosize dimension, high surface area and relatively good biocompatibility, CNTs have also been employed as a novel gene delivery vector system. In our previous work, we functionalized CNTs with two polyamine polymers, polyethyleneimine (PEI) and polyamidoamine dendrimer (PAMAM). These compounds have low cytotoxicity, ability to conjugate microRNAs (such as miR-503) and, at the same time, transfect efficiently endothelial cells. The parameters contributing to the good efficiency of transfection that we observed were not investigated in detail. In fact, the diameter and length of CNTs are important parameters to be taken into account when evaluating the effects on drug delivery efficiency. In order to investigate the biophysical and biological contributions of polymer-coated CNTs in delivery of miRNAs to human cells, we decided to investigate three different preparations, characterized by different dimensions and aspect ratios. In particular, we took into account very small CNTs, a suspension of CNTs starting from the commercial product and a 2D material based on CNTs (ie, buckypapers [BPs]) to examine the transfection efficiency of a rigid scaffold. In conclusion, we extensively investigated the biophysical and biological contributions of polyamine-coated CNTs and bidimensional BPs in the delivery of miRNAs to human cells, in order to optimize the transfection efficiency of these compounds to be employed as efficient drug delivery vectors in biomedical applications.

Carbon nanotubes as anti-bacterial agents

Multidrug-resistant bacterial infections that have evolved via natural selection have increased alarmingly at a global level. Thus, there is a strong need for the development of novel antibiotics for the treatment of these infections. Functionalized carbon nanotubes through their unique properties hold great promise in the fight against multidrug-resistant bacterial infections. This new family of nanovectors for therapeutic delivery proved to be innovative and efficient for the transport and cellular translocation of therapeutic molecules. The current review examines the latest progress in the antibacterial activity of carbon nanotubes and their composites.

Carbon Nanomaterials in Biological Studies and Biomedicine

The "carbon nano-world" has made over the past few decades huge contributions in diverse scientific disciplines and technological advances. While dramatic advances have been widely publicized in using carbon nanomaterials such as fullerenes, carbon nanotubes, and graphene in materials sciences, nano-electronics, and photonics, their contributions to biology and biomedicine have been noteworthy as well. This Review focuses on the use of carbon nanotubes (CNTs), graphene, and carbon quantum dots [encompassing graphene quantum dots (GQDs) and carbon dots (C-dots)] in biologically oriented materials and applications. Examples of these remarkable nanomaterials in bio-sensing, cell- and tissue-imaging, regenerative medicine, and other applications are presented and discussed, emphasizing the significance of their unique properties and their future potential.

Synergistic Suppression of Tumor Angiogenesis by the Co-delivering of Vascular Endothelial Growth Factor Targeted siRNA and Candesartan Mediated by Functionalized Carbon Nanovectors

Single-walled carbon nanotubes (SWNTs) with unique physicochemical properties have exhibited promising biomedical applications as drug and gene carriers. In this study, polyethylenimine (PEI)-modified SWNT conjugates linked with candesartan (CD) were developed to deliver vascular endothelial growth factor (VEGF)-targeted siRNA (siVEGF) for the synergistic and targeted treatment of tumor angiogenesis. The characterization results revealed that SWNT-PEI-CD conjugates were successfully synthesized and exhibited desirable dispersibility and superior stability. Confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) results showed that SWNT-PEI-CD/siVEGF complexes could achieve high cellular uptake and specific intracellular distribution of siRNA in AT₁R overexpressed PANC-1 cells. Strong down-regulation of VEGF was also verified by qualitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blot in complex-treated PANC-1 cells. The in vitro angiogenesis assay showed that SWNT-PEI-CD/siVEGF complexes highly inhibited tube formation of human umbilical vein endothelial cells. Furthermore, in vivo observation in PANC-1 xenografted nude mice demonstrated that SWNT-PEI-CD/siVEGF complexes exhibited significant distribution at tumor sites and caused obvious inhibition of tumor growth and tumor-associated angiogenesis repression induced by the drug combination of CD and siVEGF. Finally, a WST-1 assay indicated that SWNT-PEI-CD possessed low cytotoxicity, and a hemolysis test showed good biocompatibility of SWNT-PEI-CD. Hematological and histological analyses confirmed that SWNT-PEI-CD/siVEGF complexes did not cause any obvious toxic effects to blood and major organs. These findings suggested that the SWNT-PEI-CD/siVEGF co-delivery system with tumor-targeting specificity, improved endosomal escaping properties, and collaboration of angiogenesis inhibition could be a prospective method for efficient tumor antiangiogenic therapy.

Carbon nanotubes as gene carriers: Focus on internalization pathways related to functionalization and properties

Carbon nanotubes represent promising transporters for delivery of DNA and other biomolecules into living cells. Various methods of CNTs surface functionalization have been developed. These are essential to improve CNTs dispersibility and permit their interactions with biological structures that broaden their use in advanced biomedical applications. The present review discusses the different single walled carbon nanotubes and multiwalled carbon nanotubes functionalization methods, leading to the formation of optimized and functionalized-CNT complexes with DNA. F-CNTs are recognized as efficient and promising gene carriers. Emphasis is then placed on the processes used by f-CNTs/DNA complexes to cross cell membranes. Energy independent pathways and uptake mechanisms dependent on energy, such as endocytosis or phagocytosis, are reported by many studies, and if these mechanisms seem contradictory at first sight, a detailed review of the literature illustrates that they are rather complementary. Preferential use of one or the other depends on the DNA and CNTs chemical nature and physical parameters, experimental procedures and cell types.

STATEMENT OF SIGNIFICANCE

Efficient non-viral gene delivery is desirable, yet challenging. CNTs appear as a promising solution to penetrate into cells and successfully deliver DNA. Moreover, the field of use of CNTs as gene carrier is large and is currently growing. This critical review summarizes the development and evaluation of CNTs as intracellular gene delivery system and provides an overview of functionalized CNTs/DNA cellular uptake mechanisms, depending on several parameters of CNTs/DNA complexes.

Carbon nanotubes: a novel material for multifaceted applications in human healthcare

Remarkable advances achieved in modern material technology, especially in device fabrication, have facilitated diverse materials to expand the list of their application fields.

Multifunctional PEI-entrapped gold nanoparticles enable efficient delivery of therapeutic siRNA into glioblastoma cells

Multifunctional PEI-entrapped gold nanoparticles modified with RGD peptide via a PEG spacer enable efficient therapeutic siRNA delivery to glioblastoma cells.

Suppression of Breast Cancer Cell Migration by Small Interfering RNA Delivered by Polyethylenimine-Functionalized Graphene Oxide

The carbon-based nanomaterial graphene can be chemically modified to associate with various molecules such as chemicals and biomolecules and developed as novel carriers for drug and gene delivery. In this study, a nonviral gene transfection reagent was produced by functionalizing graphene oxide (GO) with a polycationic polymer, polyethylenimine (PEI), to increase the biocompatibility of GO and to transfect small interfering RNA (siRNA) against C-X-C chemokine receptor type 4 (CXCR4), a biomarker associated with cancer metastasis, into invasive breast cancer cells. PEI-functionalized GO (PEI-GO) was a homogeneous aqueous solution that remained in suspension during storage at 4 °C for at least 6 months. The particle size of PEI-GO was 172 ± 4.58 and 188 ± 5.00 nm at 4 and 25 °C, respectively, and increased slightly to 262 ± 17.6 nm at 37 °C, but remained unaltered with time. Binding affinity of PEI-GO toward siRNA was assessed by electrophoretic mobility shift assay (EMSA), in which PEI-GO and siRNA were completely associated at a PEI-GO:siRNA weight ratio of 2:1 and above. The invasive breast cancer cell line, MDA-MB-231, was transfected with PEI-GO in complex with siRNAs against CXCR4 (siCXCR4). Suppression of the mRNA and protein expression of CXCR4 by the PEI-GO/siCXCR4 complex was confirmed by real-time PCR and western blot analysis. In addition, the metastatic potential of MDA-MB-231 cells was attenuated by the PEI-GO/siCXCR4 complex as demonstrated in wound healing assay. Our results suggest that PEI-GO is effective in the delivery of siRNA and may contribute to targeted gene therapy to suppress cancer metastasis.

Smart Carbon Nanotubes with Laser-Controlled Behavior in Gene Delivery and Therapy through a Non-Digestive Trafficking Pathway

Near-infrared (NIR) laser-controlled gene delivery presents some benefits in gene therapy, inducing enhanced gene transfection efficiency. In this study, a "photothermal transfection" agent is obtained by wrapping poly(ethylenimine)-cholesterol derivatives (PEI-Chol) around single-walled carbon nanotubes (SWNTs). The PEI-Chol modified SWNTs (PCS) are effective in compressing DNA molecules and protecting them from DNaseI degradation. Compared to the complexes formed by PEI with DNA (PEI/DNA), complexes of PCS and DNA that are formed (PCS/DNA) exhibit a little lower toxicity to HEK293 and HeLa cells under the same PEI molecule weight and weight ratios. Notably, caveolae-mediated cellular uptake of PCS/DNA occurs, which results in a safer intracellular transport of the gene due to the decreased lysosomal degradation in comparison with that of PEI/DNA whose internalization mainly depends on clathrin rather than caveolae. Furthermore, unlike PEI/DNA, PCS/DNA exhibits a photothermal conversion ability, which promotes DNA release from PCS under NIR laser irradiation. The NIR laser-mediated photothermal transfection of PCS_10K /plasmid TP53 (pTP53) results in more apoptosis and necrosis of HeLa cells in vitro than other groups, and achieves a higher tumor-growth inhibition in vivo than naked pTP53, PEI_25K /pTP53, and PCS_10K /pTP53 alone. The enhanced transfection efficiency of PCS/DNA can be attributed to more efficient DNA internalization into the tumor cells, promotes detachment of DNA from PCS under the mediation of NIR laser and higher DNA stability in the cells due to caveolae-mediated cellular uptake of the complexes.

Multiwalled Carbon Nanotube Functionalization with High Molecular Weight Hyaluronan Significantly Reduces Pulmonary Injury

Commercialization of multiwalled carbon nanotubes (MWCNT)-based applications has been hampered by concerns regarding their lung toxicity potential. Hyaluronic acid (HA) is a ubiquitously found polysaccharide, which is anti-inflammatory in its native high molecular weight form. HA-functionalized smart MWCNTs have shown promise as tumor-targeting drug delivery agents and can enhance bone repair and regeneration. However, it is unclear whether HA functionalization could reduce the pulmonary toxicity potential of MWCNTs. Using in vivo and in vitro approaches, we investigated the effectiveness of MWCNT functionalization with HA in increasing nanotube biocompatibility and reducing lung inflammatory and fibrotic effects. We utilized three-dimensional cultures of differentiated primary human bronchial epithelia to translate findings from rodent assays to humans. We found that HA functionalization increased stability and dispersion of MWCNTs and reduced postexposure lung inflammation, fibrosis, and mucus cell metaplasia compared with nonfunctionalized MWCNTs. Cocultures of fully differentiated bronchial epithelial cells (cultivated at air-liquid interface) and human lung fibroblasts (submerged) displayed significant reduction in injury, oxidative stress, as well as pro-inflammatory gene and protein expression after exposure to HA-functionalized MWCNTs compared with MWCNTs alone. In contrast, neither type of nanotubes stimulated cytokine production in primary human alveolar macrophages. In aggregate, our results demonstrate the effectiveness of HA functionalization as a safer design approach to eliminate MWCNT-induced lung injury and suggest that HA functionalization works by reducing MWCNT-induced epithelial injury.

Regulation of angiogenesis through the efficient delivery of microRNAs into endothelial cells using polyamine-coated carbon nanotubes

MicroRNAs (miRNAs) directly regulate gene expression at a post-transcriptional level and represent an attractive therapeutic target for a wide range of diseases. Here, we report a novel strategy for delivering miRNAs to endothelial cells (ECs) to regulate angiogenesis, using polymer functionalized carbon nanotubes (CNTs). CNTs were coated with two different polymers, polyethyleneimine (PEI) or polyamidoamine dendrimer (PAMAM), followed by conjugation of miR-503 oligonucleotides as recognized regulators of angiogenesis. We demonstrated a reduced toxicity for both polymer-coated CNTs, compared with pristine CNTs or polymers alone. Moreover, polymer-coated CNT stabilized miR-503 oligonucleotides and allowed their efficient delivery to ECs. The functionality of PAMAM-CNT-miR-503 complexes was further demonstrated in ECs through regulation of target genes, cell proliferation and angiogenic sprouting and in a mouse model of angiogenesis. This comprehensive series of experiments demonstrates that the use of polyamine-functionalized CNTs to deliver miRNAs is a novel and effective means to regulate angiogenesis.

Carbon nanotubes part II: a remarkable carrier for drug and gene delivery

INTRODUCTION

Carbon nanotubes (CNT) have recently been studied as novel and versatile drug and gene delivery vehicles. When CNT are suitably functionalized, they can interact with various cell types and are taken up by endocytosis.

AREAS COVERED

Anti-cancer drugs cisplatin and doxorubicin have been delivered by CNT, as well as methotrexate, taxol and gemcitabine. The delivery of the antifungal compound amphotericin B and the oral administration of erythropoietin have both been assisted using CNT. Frequently, targeting moieties such as folic acid, epidermal growth factor or various antibodies are attached to the CNT-drug nanovehicle. Different kinds of functionalization (e.g., polycations) have been used to allow CNT to act as gene delivery vectors. Plasmid DNA, small interfering RNA and micro-RNA have all been delivered by CNT vehicles. Significant concerns are raised about the nanotoxicology of the CNT and their potentially damaging effects on the environment.

EXPERT OPINION

CNT-mediated drug delivery has been studied for over a decade, and both in vitro and in vivo studies have been reported. The future success of CNTs as vectors in vivo and in clinical application will depend on achievement of efficacious therapy with minimal adverse effects and avoidance of possible toxic and environmentally damaging effects.

Inflammasome activation in airway epithelial cells after multi-walled carbon nanotube exposure mediates a profibrotic response in lung fibroblasts

Background

In vivo studies have demonstrated the ability of multi-walled carbon nanotubes (MWCNT) to induce airway remodeling, a key feature of chronic respiratory diseases like asthma and chronic obstructive pulmonary disease. However, the mechanism leading to remodeling is poorly understood. Particularly, there is limited insight about the role of airway epithelial injury in these changes.

Objectives

We investigated the mechanism of MWCNT-induced primary human bronchial epithelial (HBE) cell injury and its contribution in inducing a profibrotic response.

Methods

Primary HBE cells were exposed to thoroughly characterized MWCNTs (1.5-24 μg/mL equivalent to 0.37-6.0 μg/cm²) and MRC-5 human lung fibroblasts were exposed to 1:4 diluted conditioned medium from these cells. Flow cytometry, ELISA, immunostainings/immunoblots and PCR analyses were employed to study cellular mechanisms.

Results

MWCNT induced NLRP3 inflammasome dependent pyroptosis in HBE cells in a time- and dose-dependent manner. Cell death and cytokine production were significantly reduced by antioxidants, siRNA to NLRP3, a caspase-1 inhibitor (z-WEHD-FMK) or a cathepsin B inhibitor (CA-074Me). Conditioned medium from MWCNT-treated HBE cells induced significant increase in mRNA expression of pro-fibrotic markers (TIMP-1, Tenascin-C, Procollagen 1, and Osteopontin) in human lung fibroblasts, without a concomitant change in expression of TGF-beta. Induction of pro-fibrotic markers was significantly reduced when IL-1β, IL-18 and IL-8 neutralizing antibodies were added to the conditioned medium or when conditioned medium from NLRP3 siRNA transfected HBE cells was used.

Conclusions

Taken together these results demonstrate induction of a NLRP3 inflammasome dependent but TGF-beta independent pro-fibrotic response after MWCNT exposure.