Carbon nanotubes (CNTs) based advanced dermal therapeutics: current trends and future potential

Development of engineered transferosomal gel containing meloxicam for the treatment of osteoarthritis

OBJECTIVE

.In this study, we investigated the potential of meloxicam (MLX) developed as transferosomal gel as a novel lipidic drug delivery system to address osteoarthritis (OTA), a degenerative joint disease that causes pain and stiffness. By incorporating meloxicam into a transferosomal gel, our aim was to provide a targeted and efficient delivery system capable of alleviating symptoms and slowing down the progression of OTA.

MATERIAL AND METHODS

Classical lipid film hydration technique was utilized to formulate different transferosomal formulations. Different transferosomal formulations were prepared by varying the molar ratio of phospholipon-90H (phosphodylcholine) to DSPE (50:50, 60:40, 70:30, 80:20, and 90:10) and per batch, 80mg of total lipid was used. The quality control parameters such as entrapment efficiency, particle size and morphology, polydispersity and surface electric charge, in vitro drug release, ex vivo permeation and stability were measured.

RESULTS

The optimized transferosomal formulations revealed a small vesicle size (121±12nm) and greater MLX entrapment (68.98±2.3%). Transferosomes mediated gel formulation MLX34 displayed pH (6.3±0.2), viscosity (6236±12.3 cps), spreadability (13.77±1.77 gm.cm/sec) and also displayed sustained release pattern of drug release (81.76±7.87% MLX released from Carbopol-934 gel matrix in 24h). MLX34 revealed close to substantial anti-inflammatory response, with ∼81% inhibition of TNF-α in 48h. Physical stability analysis concluded that refrigerator temperature was the preferred temperature to store transferosomal gel.

CONCLUSION

MLX loaded transferosomes containing gel improved the skin penetration and therefore resulted into increased inhibition of TNF-α level.

Single-Walled Carbon Nanotube-Guided Topical Skin Delivery of Tyrosinase to Prevent Photoinduced Damage

When the skin is exposed to ultraviolet radiation (UV), it leads to the degradation of the extracellular matrix (ECM) and results in inflammation. Subsequently, melanocytes are triggered to induce tyrosinase-mediated melanin synthesis, protecting the skin. Here, we introduce a proactive approach to protect the skin from photodamage via the topical delivery of Streptomyces avermitilis-derived tyrosinase (SaTy) using single-walled carbon nanotube (SWNT). Utilizing a reverse electrodialysis (RED) battery, we facilitated the delivery of SaTy-SWNT complexes up to depths of approximately 300 μm, as analyzed by using confocal Raman microscopy. When applied to ex vivo porcine skin and in vivo albino mouse skin, SaTy-SWNT synthesized melanin, resulting in 4-fold greater UV/vis absorption at 475 nm than in mice without SaTy-SWNT. The synthesized melanin efficiently absorbed UV light and alleviated skin inflammation. In addition, the densification of dermal collagen, achieved through SaTy-mediated cross-linking, reduced photoinduced wrinkles by 66.3% in the affected area. Our findings suggest that SWNT-mediated topical protein delivery holds promise in tissue engineering applications.

Mechanisms of theaflavins against gout and strategies for improving the bioavailability

BACKGROUND

Gout is a crystal related arthropathy caused by monosodium urate deposition. At present, the identification of appropriate treatments and new drugs to reduce serum uric acid levels and gout risk is a major research area.

PURPOSE

Theaflavins are naturally occurring compounds characterized by a benzodiazepine skeleton. The significant benefits of theaflavins have been well documented. A large number of studies have been carried out and excellent anti-gout results have been achieved in recent years.

STUDY DESIGN

A comprehensive analysis of the mechanism of the anti-gout effect of theaflavins is presented through a literature review and network pharmacology prediction, and strategies for increasing the bioavailability of theaflavins are summarized.

METHODS

In this review, the active components and pharmacological mechanisms of theaflavins in the treatment of gout were summarized, and the relationship between theaflavins and gout, the relevant components, and the potential mechanisms of anti-gout action were clarified by reviewing the literature on the anti-gout effects of theaflavins and network pharmacology.

RESULTS

Theaflavins exert anti-gout effects by down regulating the gene and protein expression of glucose transporter 9 (GLUT9) and uric acid transporter 1 (URAT1), while upregulating the mRNA expression levels of organic anion transporter 1 (OAT1), organic cation transporter N1 (OCTN1), organic cation transporters 1/2 (Oct1/2), and organic anion transporter 2 (OAT2). Network pharmacology prediction indicate that theaflavins can regulate the AGE-RAGE and cancer signaling pathways through ATP-binding cassette subfamily B member 1 (ABCB1), recombinant mitogen activated protein kinase 14 (MAPK14), telomerase reverse tranase (TERT), signal transducer and activator of transcription 1 (STAT1), matrix metalloproteinase 2 (MMP2), B-cell lymphoma-2 (BCL2), and matrix metalloproteinase 14 (MMP14) targets for anti-gout effects.

CONCLUSION

This review presents the mechanisms of anti-gout action of theaflavins and strategies for improving the bioavailability of theaflavins, as well as providing research strategies for anti-gout treatment measures and the development of novel anti-gout drugs.

In vitro comparative cytotoxic assessment of pristine and carboxylic functionalized multiwalled carbon nanotubes on LN18 cells

Multiwalled carbon nanotubes (MWCNTs) have been used in biomedical applications due to their ability to enter the cells. Carboxylic functionalization of MWCNT (MWCNT-COOH) is used to mitigate the toxicity of MWCNTs. Our study focuses on comparing the toxicity of MWCNT and MWCNT-COOH on the neuronal cells, LN18. Concentrations of 5, 10, 20, and 40 µg ml-1 were used for the study, and cytotoxicity was determined at 0, 1, 3, 6, 12, 24, and 48 h of incubation. Cell viability was assessed by Trypan Blue, MTT, and Live dead cell assays, and the oxidative stress produced was determined by reactive oxygen species (ROS) and Lipid peroxidation assays. MWCNT-COOH showed higher cell viability than MWCNT for 20 and 40 µg ml-1 at 24 and 48 h. This was also visually observed in the live dead cell imaging. However, at 48 h, the morphology of the cells appeared more stretched for all the concentrations of MWCNT and MWCNT-COOH in comparison to the control. A significant amount of ROS production can also be observed at the same concentration and time. Viability and oxidative stress results together revealed that MWCNT-COOH is less toxic when compared to MWCNT at longer incubation periods and higher concentrations. However, otherwise, the effect of both are comparable. A concentration of 5-10 µg ml-1 is ideal while using MWCNT and MWCNT-COOH as the toxicity is negligible. These findings can further be extended to various functionalizations of MWCNT for wider applications.

A Promising Approach of Dermal Targeting of Antipsoriatic Drugs via Engineered Nanocarriers Drug Delivery Systems for Tackling Psoriasis

Psoriasis is a complex autoimmune skin condition with a significant genetic component. It causes skin inflammation and is characterized by flaky, silvery reddish spots that can worsen with age. This condition results from an impaired immunological response of T-cells and affects 2-5% of the global population. The severity of the illness determines the choice of treatment. Topical treatments are commonly used to treat psoriasis, but they can have several adverse effects. Biological therapy is another option for treating specific types of psoriasis. Recently, new nanoformulations have revolutionized psoriasis treatment. Various nanocarriers, such as liposomes, nanostructured lipid nanoparticles, niosomes, and nanoemulsions, have been developed and improved for drug delivery. The use of nanocarriers enhances patient compliance, precise drug delivery, and drug safety. This review aims to suggest new nanocarrier-based drug delivery systems for treating psoriasis. It discusses the importance of nanocarriers and compares them to traditional treatments. Anti-psoriatic drugs have also been investigated for cutaneous delivery using nanocarriers. The review also covers various factors that influence dermal targeting. By highlighting several relevant aspects of psoriasis treatment, the review emphasizes the current potential of nanotechnology. Using nanocarriers as a drug delivery technique may be a promising alternative treatment for psoriasis.

Electrospun Nanofibers for Bone Regeneration: From Biomimetic Composition, Structure to Function

In recent years, a variety of novel materials and processing technologies have been developed to prepare tissue engineering scaffolds for bone defect repair. Among them, nanofibers fabricated via electrospinning technology...

The Factors Determining the Skin Penetration and Cellular Uptake of Nanocarriers: New Hope for Clinical Development

The skin provides a protective barrier against toxic environments and also offers a valuable route for topical drug delivery. The stratum corneum (SC) is the outermost layer of the skin and serves as the major barrier to chemical transfer through the skin. The human skin barrier is particularly difficult to overcome because of the complex composition and structure of the SC. Nanoparticulate carriers have gained widespread attention in topical drug delivery due to their tunable and versatile properties. The present review summarizes the main factors involved in skin penetration of nanocarriers containing the drug. Employment of nanotechnology in topical delivery has grown progressively during recent years; however, it is important to monitor the skin penetration of nanocarriers prior to their use to avoid possible toxic effects. Nanocarriers can act as a means to increase skin permeation of drugs by supporting direct interaction with the SC and increasing the period of permanence on the skin. Skin penetration is influenced by the physicochemical characteristics of nanocarriers such as composition, size, shape, surface chemistry, as well as skin features. Considering that the target of topical systems based on nanocarriers is the penetration of therapeutic agents in the skin layers, so a detailed understanding of the factors influencing skin permeability of nanocarriers is essential for safe and efficient therapeutic applications.

Vesicle Impact Electrochemical Cytometry to Determine Carbon Nanotube-Induced Fusion of Intracellular Vesicles

Carbon nanotube (CNT)-modified electrodes are used to obtain new measurements of vesicle content via amperometry. We have investigated the interaction between CNTs and isolated adrenal chromaffin vesicles (as a model) by vesicle impact electrochemical cytometry. Our data show that the presence of CNTs not only significantly increased the vesicular catecholamine number from 2,250,000 ± 112,766 molecules on a bare electrode to 3,880,000 ± 686,573 molecules on CNT/carbon fiber electrodes but also caused an enhancement in the maximum intensity of the current, which implies the existence of strong interactions between vesicle biolayers and CNTs and an altered electroporation process. We suggest that CNTs might perturb and destabilize the membrane structure of intracellular vesicles and cause the aggregation or fusion of vesicles into new vesicles with larger size and higher content. Our findings are consistent with previous computational and experimental results and support the hypothesis that CNTs as a mediator can rearrange the phospholipid bilayer membrane and trigger homotypic fusion of intracellular vesicles.

Nanosystems in Cosmetic Products: A Brief Overview of Functional, Market, Regulatory and Safety Concerns

Nanosystems exhibit various innovative physico-chemical properties as well as a range of cosmetic functions, including increased skin retention for loaded compounds. The worldwide nano-market has therefore been consistently extensive in recent decades. This review summarizes the most important properties of nanosystems that are employed in cosmetics, including composition, functions and interactions with skin, with particular attention being paid to marketed products. Moreover, the worldwide regulatory landscape of nanomaterials used as cosmetic ingredients is considered, and the main safety concerns are indicated. In general, advanced physico-chemical characterization is preliminarily needed to assess the safety of nanomaterials for human health and the environment. However, there is currently a shortfall in global legislation as a universally accepted and unambiguous definition of a nanomaterial is still lacking. Therefore, each country follows its own regulations. Anyhow, the main safety concerns arise from the European context, which is the most restrictive. Accordingly, the poor dermal permeation of nanomaterials generally limits their potential toxic effects, which should be mainly ascribed to unwanted or accidental exposure routes.

Nanomedicines and microneedles: a guide to their analysis and application

The fast-advancing progress in the research of nanomedicine and microneedle applications in the past two decades has suggested that the combination of the two concepts could help to overcome some of the challenges we are facing in healthcare. They include poor patient compliance with medication and the lack of appropriate administration forms that enable the optimal dose to reach the target site. Nanoparticles as drug vesicles can protect their cargo and deliver it to the target site, while evading the body's defence mechanisms. Unfortunately, despite intense research on nanomedicine in the past 20 years, we still haven't answered some crucial questions, e.g. about their colloidal stability in solution and their optimal formulation, which makes the translation of this exciting technology from the lab bench to a viable product difficult. Dissolvable microneedles could be an effective way to maintain and stabilise nano-sized formulations, whilst enhancing the ability of nanoparticles to penetrate the stratum corneum barrier. Both concepts have been individually investigated fairly well and many analytical techniques for tracking the fate of nanomaterials with their precious cargo, both in vitro and in vivo, have been established. Yet, to the best of our knowledge, a comprehensive overview of the analytical tools encompassing the concepts of microneedles and nanoparticles with specific and successful examples is missing. In this review, we have attempted to briefly analyse the challenges associated with nanomedicine itself, but crucially we provide an easy-to-navigate scheme of methods, suitable for characterisation and imaging the physico-chemical properties of the material matrix.

Current Advances of Nanocarrier Technology-Based Active Cosmetic Ingredients for Beauty Applications

Nanocarrier technology has been effectively applied to the development of drug delivery systems to overcome the limitations of traditional preparation. Its application has been extended to various pharmaceutical fields from injection preparation to oral preparation and external preparation, and now it has appeared in the field of cosmetics for beauty applications. The widespread influence of nanocarrier in the cosmetics industry is due to the fact that nanocarrier can effectively promote the percutaneous penetration and significantly increase skin retention of active components in functional cosmetics. Meanwhile, nanocarrier can effectively improve the water dispersion of insoluble active cosmetic ingredients, enhance the stability of efficacy components and achieve the codelivery of diverse cosmetics active ingredients. In this review, we summarized the current progress of nanocarrier technology in the functional cosmetics, including the types and the routes of dermal/transdermal drug delivery nanocarriers used in the functional cosmetics, the mechanism of nanocarriers promoting the percutaneous penetration of active cosmetic ingredients, the application and efficacy evaluation of different active cosmetic ingredients in nanocarriers and discussing the potential risks to human. This will provide a useful reference for the further development of nanocarriers in the field of functional cosmetics.

Topical Application of Peptide-Chondroitin Sulfate Nanoparticles Allows Efficient Photoprotection in Skin

In this article, we describe a method of delivery of chondroitin sulfate to skin as nanoparticles and demonstrate its anti-inflammatory and antioxidant role using UV irradiation as a model condition. These nanoparticles, formed through electrostatic interactions of chondroitin sulfate with a skin-penetrating peptide, were found to be homogenous with positive surface charges and stable at physiological and acidic pH under certain conditions. They were able to enter into the human keratinocyte cell line (HaCaT), artificial skin membrane (mimicking the human skin), and mouse skin tissue unlike free chondroitin sulfate. The preapplication of nanoparticles also exhibited reduced levels of oxidative stress, cyclobutane pyrimidine dimer formation, TNF-α, and so on in UV-B-irradiated HaCaT cells. In an acute UV-B irradiation mouse model, their topical application resulted in reduced epidermal thickness and sunburn cells, unlike in the case of free chondroitin sulfate. Thus, a completely noninvasive method was used to deliver a bio-macromolecule into the skin without using injections or abrasive procedures.

Nanocomposite adhesive hydrogels: from design to application

Hydrogels may exhibit strong adhesion upon embedding nanoparticles into them forming strong/weak bonds (via the multiple physical or chemical interactions).

A bird's eye view of the advanced approaches and strategies for overshadowing triple negative breast cancer

Triple negative breast cancer (TNBC) is one of the most aggressive form of breast cancer. It is characterized by the absence of estrogen, progesterone and human epidermal growth factor receptors. The main issue with TNBC is that it exhibits poor prognosis, high risk of relapse, short progression-free survival and low overall survival in patients. This is because the conventional therapy used for managing TNBC has issues pertaining to poor bioavailability, lower cellular uptake, increased off-target effects and development of resistance. To overcome such pitfalls, several other approaches are explored. In this context, the present manuscript showcases three of the most widely used approaches which are (i) nanotechnology-based approach; (ii) gene therapy approach and (iii) Phytochemical-based approach. The ultimate focus is to present and explain the insightful reports based on these approaches. Further, the review also expounds on the identified molecular targets and novel targeting ligands which are explored for managing TNBC effectively. Thus, in a nutshell, the review tries to highlight these existing treatment approaches which might inspire for future development of novel therapies with a potential of overshadowing TNBC.

Wicking-Driven Evaporation Self-Assembly of Carbon Nanotubes on Fabrics: Generating Controlled Orientational Structures

Nanostructures with orientational order exhibit excellent electrical and optical properties; however, their construction on complex fabrics is challenging. Here, we demonstrate the potential of wicking-driven evaporation self-assembly in the oriented arrangement of carbon nanotubes (CNTs) on fabrics. The solution-evaporation self-assembly in combination with the fabric wicking effect leads to convective flows along the fibers, which makes it possible to prepare orientational nanostructures over large fabric surface areas. The orientation of CNTs is controlled by the fluid drag force from the convective flow during drying, thus the interaction between the CNT and the solution is crucial. We show that the nanostructures of CNTs on fibers depend, for example, on the evaporation temperature, component concentration, and solution pH. Weakening the viscous connection of the fluid with CNTs can lead to an interesting eddy nanostructure of CNTs. The electrical conductivity of the assembled fabrics increases strongly with the degree of orientation and the assembly cycles of CNTs. In this work, the large-scale orientational order of nanomaterial achieved by wicking-driven evaporation self-assembly offers a new strategy for constructing three-dimensional oriented conductive networks in electronic textiles.

Carbon Nanotubes (CNTs)-Reinforced Magnesium-Based Matrix Composites: A Comprehensive Review

In recent years considerable attention has been attracted to magnesium because of its light weight, high specific strength, and ease of recycling. Because of the growing demand for lightweight materials in aerospace, medical and automotive industries, magnesium-based metal matrix nanocomposites (MMNCs) reinforced with ceramic nanometer-sized particles, graphene nanoplatelets (GNPs) or carbon nanotubes (CNTs) were developed. CNTs have excellent material characteristics like low density, high tensile strength, high ratio of surface-to-volume, and high thermal conductivity that makes them attractive to use as reinforcements to fabricate high-performance, and high-strength metal-matrix composites (MMCs). Reinforcing magnesium (Mg) using small amounts of CNTs can improve the mechanical and physical properties in the fabricated lightweight and high-performance nanocomposite. Nevertheless, the incorporation of CNTs into a Mg-based matrix faces some challenges, and a uniform distribution is dependent on the parameters of the fabricating process. The characteristics of a CNTs reinforced composite are related to the uniform distribution, weight percent, and length of the CNTs, as well as the interfacial bonding and alignment between CNTs reinforcement and the Mg-based matrix. In this review article, the recent findings in the fabricating methods, characterization of the composite's properties, and application of Mg-based composites reinforced with CNTs are studied. These include the strategies of fabricating CNT-reinforced Mg-based composites, mechanical responses, and corrosion behaviors. The present review aims to investigate and conclude the most relevant studies conducted in the field of Mg/CNTs composites. Strategies to conquer complicated challenges are suggested and potential fields of Mg/CNTs composites as upcoming structural material regarding functional requirements in aerospace, medical and automotive industries are particularly presented.

Vertically-Aligned Multi-Walled Carbon Nano Tube Pillars with Various Diameters under Compression: Pristine and NbTiN Coated

In this paper, the compressive stress of pristine and coated vertically-aligned (VA) multi-walled (MW) carbon nanotube (CNT) pillars were investigated using flat-punch nano-indentation. VA-MWCNT pillars of various diameters (30-150 µm) grown by low-pressure chemical vapor deposition on silicon wafer. A conformal brittle coating of niobium-titanium-nitride with high superconductivity temperature was deposited on the VA-MWCNT pillars using atomic layer deposition. The coating together with the pillars could form a superconductive vertical interconnect. The indentation tests showed foam-like behavior of pristine CNTs and ceramic-like fracture of conformal coated CNTs. The compressive strength and the elastic modulus for pristine CNTs could be divided into three regimes of linear elastic, oscillatory plateau, and exponential densification. The elastic modulus of pristine CNTs increased for a smaller pillar diameter. The response of the coated VA-MWCNTs depended on the diffusion depth of the coating in the pillar and their elastic modulus increased with pillar diameter due to the higher sidewall area. Tuning the material properties by conformal coating on various diameter pillars enhanced the mechanical performance and the vertical interconnect access (via) reliability. The results could be useful for quantum computing applications that require high-density superconducting vertical interconnects and reliable operation at reduced temperatures.

Carbon Nanotubes-Based Nanomaterials and Their Agricultural and Biotechnological Applications

Carbon nanotubes (CNTs) are considered a promising nanomaterial for diverse applications owing to their attractive physicochemical properties such as high surface area, superior mechanical and thermal strength, electrochemical activity, and so on. Different techniques like arc discharge, laser vaporization, chemical vapor deposition (CVD), and vapor phase growth are explored for the synthesis of CNTs. Each technique has advantages and disadvantages. The physicochemical properties of the synthesized CNTs are profoundly affected by the techniques used in the synthesis process. Here, we briefly described the standard methods applied in the synthesis of CNTs and their use in the agricultural and biotechnological fields. Notably, better seed germination or plant growth was noted in the presence of CNTs than the control. However, the exact mechanism of action is still unclear. Significant improvements in the electrochemical performances have been observed in CNTs-doped electrodes than those of pure. CNTs or their derivatives are also utilized in wastewater treatment. The high surface area and the presence of different functional groups in the functionalized CNTs facilitate the better adsorption of toxic metal ions or other chemical moieties. CNTs or their derivatives can be applied for the storage of hydrogen as an energy source. It has been observed that the temperature widely influences the hydrogen storage ability of CNTs. This review paper highlighted some recent development on electrochemical platforms over single-walled CNTs (SWCNTs), multi-walled CNTs (MWCNTs), and nanocomposites as a promising biomaterial in the field of agriculture and biotechnology. It is possible to tune the properties of carbon-based nanomaterials by functionalization of their structure to use as an engineering toolkit for different applications, including agricultural and biotechnological fields.

Preparation, characterization and controlled-release property of CS crosslinked MWCNT based on Hericium erinaceus polysaccharides

In present study, the optimal condition of prepared drug was determined by response surface methodology. In addition, their physicochemical properties, drug release and uptake ability of CS-MWCNT-HEP were studied, and the distribution of the drug in ICR mice and the sites of action were further evaluated. Under the optimal condition, the mean experimental loaded efficiency 68.55 ± 1.47% was corresponded well with the predicted value of 68.28%. The results of in vitro experiments proved that a release of the drug in a pH-dependent behavior. Flow cytometry and inverted microscope showed that the uptake of CS-MWCNT-HEP in Raw264.7 cells increased significantly as the time increased. In vivo experiment proved that the HEP and CS-MWCNT-HEP were mainly accumulated in the kidney, shown the characteristics of kidney metabolism. On the other hand, the extended retention of CS-MWCNT-HEP in the mice could enhance the immune function. CS-MWCNT-HEP has high loaded efficiency and pH-responsive drug released, which could significantly improved the body's immunity and enhance the body's ability to absorbed drugs. These findings proposed a well characterized novel CS-MWCNT-HEP formulation as drug delivery system, and its mechanism and application will be further investigated in our undergoing studies.

Precise cell behaviors manipulation through light-responsive nano-regulators: recent advance and perspective

Nanotechnology-assisted spatiotemporal manipulation of biological events holds great promise in advancing the practice of precision medicine in healthcare systems. The progress in internal and/or external stimuli-responsive nanoplatforms for highly specific cellular regulations and theranostic controls offer potential clinical translations of the revolutionized nanomedicine. To successfully implement this new paradigm, the emerging light-responsive nanoregulators with unparalleled precise cell functions manipulation have gained intensive attention, providing UV-Vis light-triggered photocleavage or photoisomerization studies, as well as near-infrared (NIR) light-mediated deep-tissue applications for stimulating cellular signal cascades and treatment of mortal diseases. This review discusses current developments of light-activatable nanoplatforms for modulations of various cellular events including neuromodulations, stem cell monitoring, immunomanipulation, cancer therapy, and other biological target intervention. In summary, the propagation of light-controlled nanomedicine would place a bright prospect for future medicine.

Overview of Carbon Nanotubes for Biomedical Applications

The unique combination of mechanical, optical and electrical properties offered by carbon nanotubes has fostered research for their use in many kinds of applications, including the biomedical field. However, due to persisting outstanding questions regarding their potential toxicity when considered as free particles, the research is now focusing on their immobilization on substrates for interface tuning or as biosensors, as load in nanocomposite materials where they improve both mechanical and electrical properties or even for direct use as scaffolds for tissue engineering. After a brief introduction to carbon nanotubes in general and their proposed applications in the biomedical field, this review will focus on nanocomposite materials with hydrogel-based matrices and especially their potential future use for diagnostics, tissue engineering or targeted drug delivery. The toxicity issue will also be briefly described in order to justify the safe(r)-by-design approach offered by carbon nanotubes-based hydrogels.

Multi-walled carbon nanotube oxidation dependent keratinocyte cytotoxicity and skin inflammation

BACKGROUND

The effects of carbon nanotubes on skin toxicity have not been extensively studied; however, our lab has previously shown that a carboxylated multi-walled carbon nanotube (MWCNT) exacerbates the 2, 4-dinitrofluorobenzene induced contact hypersensitivity response in mice. Here we examine the role of carboxylation in MWCNT skin toxicity.

RESULTS

MWCNTs were analyzed by transmission electron microscopy, zetasizer, and x-ray photoelectron spectroscopy to fully characterize the physical properties. Two MWCNTs with different levels of surface carboxylation were chosen for further testing. The MWCNTs with a high level of carboxylation displayed increased cytotoxicity in a HaCaT keratinocyte cell line, compared to the MWCNTs with intermediate levels of carboxylation. However, neither functionalized MWCNT increased the level of in vitro reactive oxygen species suggesting an alternative mechanism of cytotoxicity. Each MWCNT was tested in the contact hypersensitivity model, and only the MWCNTs with greater than 20% surface carboxylation exacerbated the ear swelling responses. Analysis of the skin after MWCNT exposure reveals that the same MWCNTs with a high level of carboxylation increase epidermal thickness, mast cell and basophil degranulation, and lead to increases in polymorphonuclear cell recruitment when co-administered with 2, 4-dinitrofluorobenzene.

CONCLUSIONS

The data presented here suggest that acute, topical application of low doses of MWCNTs can induce keratinocyte cytotoxicity and exacerbation of allergic skin conditions in a carboxylation dependent manner.

Drug-Phospholipid Complex-a Go Through Strategy for Enhanced Oral Bioavailability

Among many, the oral route of delivery is considered to be the most favorable route with the highest patient compliance. The main issue with oral delivery is the environmental vulnerability of gastro intestinal tract (G.I.T). The bioavailability could further decrease when drug has poor aqueous solubility and permeability through biological membrane. This drawback could be resolved by employing drug-phospholipid complex strategy, as they utilize mechanism which is similar to the absorption mechanism of nutritional constituents form G.I.T. The drug-phospholipid complexes are considered ideal for oral delivery as they are biodegradable and non-toxic, which enable them to be employed as solubilizer, emulsifier, and as a matrix forming excipient for dugs with poor solubility and/or permeability. The present review compiles the basic know how about the phospholipids and the mechanism through which it improves the bioavailability of drugs. Further, it also compiles the crucial formulation aspects and methods of preparations of drug-phospholipid complex along with its physical and in silico characterization techniques. The increase in number of recent reports involving the utilization of drug-phospholipid complex to improve oral bioavailability of drugs thus explains how vital the strategy is for a successful oral delivery.

Planting carbon nanotubes onto supramolecular polymer matrices for waterproof non-contact self-healing

Supramolecular polymers show unique and excellent properties due to the reversible and designable nature of the non-covalent interactions. Herein, ureido-pyrimidinone (UPy)-based supramolecular polymers were employed to fabricate the thermo-responsive composite materials with multi-walled carbon nanotubes (MWCNTs) by planting the MWCNTs onto the supramolecular polymer matrices via a simple surface spraying procedure. The MWCNTs coating on the surface of the supramolecular polymer matrices gave the composite film superhydrophobic and conductive properties, and it had a non-contact healable ability underwater under 808 nm near-infrared light (NIR) irradiation. Moreover, the UPy-based supramolecular polymers acted as thermo-responsive matrices to guarantee the self-healing properties at a relatively low temperature, such as body temperature (33 °C-34 °C). The supramolecular polymer/MWCNTs composite materials exhibited excellent strain sensitivities and could be used to prepare human motion-monitoring devices. This line of research may find a promising practical application in healable wearable devices used in underwater environments.

Functionalized carbon nanotubes as emerging delivery system for the treatment of cancer

In recent time, carbon nanotubes (CNTs) have gained vital importance for pharmaceutical formulation scientist for delivering drugs and genes, owing to their excellent surface properties. For example, their aspect ratio is thought to be responsible for their excellent cell penetration aptitude; anisotropic conductivity/semi-conductivity along their axis is ideal for integration with nervous and muscular tissue; an ultrahigh surface area maximizes their ability to "talk" with biological matter; the hollow interior provides an enormous cargo-carrying capacity for drug delivery; and their exteriors are readily functionalized to permit tailoring of solubility and biological recognition. Despite their immense capabilities for the delivery of drugs, genes and other biomedically essential materials, there use is restricted primarily because of the severe toxicity. However, the reactive nature of the surface of the CNTs allowed attaching the guest molecules (drug, siRNA, and diagnostics) of interest which helps in increasing the biocompatibility of these novel nanocarriers. As per the need, CNTs can be modified with peptides, organic molecules, carbohydrates, polymers and used mainly for cancer targeting and tumor cell accumulation. This review expounds different functionalization strategies employed for CNTs that created new opportunities for scientists to improve the potential of delivered therapeutics.