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Green Synthesis of Nanoparticles and Their Antimicrobial Efficacy against Drug-Resistant Staphylococcus aureus
Published in Richard L. K. Glover, Daniel Nyanganyura, Rofhiwa Bridget Mulaudzi, Maluta Steven Mufamadi, Green Synthesis in Nanomedicine and Human Health, 2021
Nonhlanhla Tlotleng, Marian Jiya John, Dumisile W. Nyembe, Wells Utembe
Fullerenes, also known as C60, are closed-cage carbon allotrope soccer ball-shaped NMs of different shapes, sizes and charges, due to derivatization with various functional groups. Fullerenes have been shown to possess antimicrobial activity against many species of bacteria, including S. aureus. In a study by Kumar and Menon (2009), fullerenes derivatized with s-triazine analogues were shown to possess antimicrobial activity against S. aureus at an MIC of 6.5 µg/ml, comparable to the antimicrobial drug, ciprofloxacin. Generally, the fullerenes antimicrobial activity observed has been attributed to cell membrane disruption as well as inhibition of energy metabolism and respiration following internalization by bacteria (Dizaj et al., 2015).
Theranostics: A New Holistic Approach in Nanomedicine
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
Ankit Rochani, Sreejith Raveendran
Buckminsterfullerene (C60) or fullerene is a carbon allotrope that was discovered in 1985. It has sp2-hybridized zero-dimensional carbon nanomaterials [96]. Fullerenes have interesting photophysical properties and can cause the generation of reactive oxygen species (ROSs) that could help in the creation of photodynamic therapies. Fullerence has a hollow cage structure that provides interesting possibilities to alter it and turn the molecule into metallofullerene or functionalized fullerene. These functionalized fullerenes (Gd III diethyltriaminepentaacetic acid (Gd(III)-DTPA) and Gd-tetraazacyclododecanetetraacetic acid (Gd(III)-DOTA)) have been currently marketed as Omniscan® and ProHance® as contrast agents for MRI scanning. The major limitation is the release of free metal ions upon the metabolism of Gd+3 chelate complexes, leading to toxicities. Hence, Gd is encapsulated in the fullerene cages to preserve the metallic properties and prevent the release of the metal ion that can provide less toxicity. The two most commonly explored structures are Gd@Cn (n = 60 and 82) (shown in Figure 14.6) and Gd3N@C80 for the contrast imaging applications [97]. Further, by ion implantation, researchers developed a new material, endohedral iron-fullerene [98]. Another study shows that iron carbonyl complexes with C60 and C70 by irradiation of Fe(CO)5 to a thin sheet of C60 and C70 [99]. Apart from being used as imaging material, fullerenes like hydroxyl (Figure 14.6) and carboxyl have demonstrated hyperthermia properties when exposed to low-intensity lasers [100]. Probably these new materials could be an important key to the development of structures like metal (Gd)-encapsulated or tagged fullerene. Although the structure of fullerenes gives limited access for surface functionalization, researchers used conjugation chemistry to develop C60@Au-PEG/DOX for theranostic application. The system provided a four-in-one photodynamic, hyperthermia, and chemotherapeutic effects, where materials like Au and DOX can provide fluorescence and metallic contrast for X-ray imaging-based diagnostic capabilities [101, 102]. Due to limitations for conjugation of C60 (methoxy polyethylene glycol) mPEG-GO was used to create mPEG-GO-C60 hydride for developing photodynamic and photothermal therapy. This system could be an interesting theranostic system [103].
3D self-assembled nanocarriers for drug delivery
Published in Drug Metabolism Reviews, 2023
Hossein Karballaei Mirzahosseini, Mojgan Sheikhi, Farhad Najmeddin, Mehrnoosh Shirangi, Mojtaba Mojtahedzadeh
Carbon nanotubes are a new member of the family of carbon allotrope groups that also includes graphite and fullerene. This is similar to self-assembled carbon nano-sponge, which makes use of the compact, well-aligned, and clean surface properties of well-aligned CNTs (Luo et al. 2017). A continuous and solid three-dimensional network of super aligned CNTs was produced using ultrasonic and co-deposition. Only hyper aligned CNTs are capable of forming this network since regular CNTs are unaffected by the nanotube molecules’ close bonding (Jasinski et al. 2017). Additionally, CNTs have been used as an effective nanoformulation for applications such as gene therapy and medication delivery. More particularly, SWCNTs’ aromatic surface encourages interactions with aromatic medicines like DOX that involve (supramolecular) stacking (DOX). The DOX-loaded SW-CNTs demonstrate an improved therapeutic anti-tumor activity and less toxicity than the free DOX, and they have higher loading capacities than liposomes or micelles. For the delivery of the medication DOX to tumor locations, a new pH-responsive and FA-modified MW-CNT has recently been proposed. The anticancer (in vivo) studies showed that the MWCNTs nanocarriers promote the inhibition of tumor development and lessen the adverse effects associated with free DOX. The nanocarrier also demonstrated remarkable colloidal stability and high drug encapsulation efficiency (70.4%) (Wang et al. 2006).
Comparison of the effects of multiwall carbon nanotubes on the epithelial cells and macrophages
Published in Nanotoxicology, 2019
Masanori Horie, Yosuke Tabei, Sakiko Sugino, Hiroko Fukui, Ayako Nishioka, Yuji Hagiwara, Kei Sato, Tadashi Yoneda, Atsumi Tada, Tamami Koyama
Carbon nanotubes (CNTs) are a type of carbon fiber and a carbon allotrope like fullerene and diamond. CNTs with a diameter of 1–100 nm are classified as nano-objects. A CNT is formed by a coaxial tube of six-membered rings, like a graphene sheet formed into a cylinder. CNTs are broadly classified into two groups, singlewall CNTs and multiwall CNTs (MWCNTs), depending on their structure. MWCNTs are nested structures consisting of many CNTs. CNTs have many prospective applications in electronics. However, their possible harmful effects should be considered because they are fibrous nano-objects. Generally, nanocarbons such as fullerene, nanodiamond, and carbon black exert low cellular effects and pulmonary toxicity because they do not release metal ions (Horie et al. 2010, 2012c, 2014). However, compared with these particulate nano-objects, CNTs exhibit more harmful effects. An MWCNT product, MWNT-7, has been classified as Group 2B (‘possibly carcinogenic to humans’) by the International Agency for Research on Cancer (IARC). Several studies have reported the toxicity of MWNT-7, including its carcinogenicity in animals. Intraperitoneal application of MWNT-7 to p53 (±) mice caused mesothelioma (Takagi et al. 2008). Inhalation of MWNT-7 induced tumor formation in rats. Rats subjected to continuous inhalation of MWNT-7 for 6 h/day and 5 days/week for approximately 2 years at a dose of 0.2 and 2 mg/m3 showed increased rates of bronchioloalveolar carcinoma and adenoma (Kasai et al. 2016). MWNT-7 also caused Nrf-2–related inflammation and fibrosis in mouse lungs (Dong and Ma 2016). Overall, exposure to MWNT-7 leads to inflammation, fibrosis, and carcinogenesis in the abdominal cavity and respiratory apparatus. However, the cause and mechanism of these effects are still unclear. Because MWNT-7 is no longer in production owing to its carcinogenicity, further investigation of the mechanism underlying its toxicity is difficult.
Biomedical applications and toxicities of carbon nanotubes
Published in Drug and Chemical Toxicology, 2022
Shiv Kumar Prajapati, Akanksha Malaiya, Payal Kesharwani, Deeksha Soni, Aakanchha Jain
Nanotechnology has always attracted attention of the scientific community for the development of nanocarriers for biomedical applications. Carbon nanotubes (CNTs), due to its unique arrangement of carbon atoms, sp2 hybridization, cylindrical structure with C–C distance of 1.42 Å and an interlayer arrangement of 3.4 Å, make them different from other nanocarriers. CNTs are esteemed members of synthetic carbon allotrope. CNTs are well assembled, and due to distinctive electrical, thermal, optical, mechanical, and biological properties, CNTs have been utilized for drug delivery, gene delivery, vaccine delivery, and other biomedical applications. In current scenario, CNTs have paid attention in nanotechnology and nanomedicine (Raval et al.2018). Wide applications of CNTs are due to (i) their hollow and large surface area which makes CNT suitable for drug delivery; (ii) hydrophobicity, which increases the possibility of biomolecules delivery (DNA, RNA, protein, immunomodulator, etc.); and (iii) combined use of contrast agent, photodynamic therapy, photoacoustic imaging is possible due to its better optical properties. Excellent conductivity ensures its uses in different kinds of biosensors (enzyme biosensors, gene biosensors, cancer biosensors, air pollution biosensor); (iv) solubility/dispersibility of the CNTs, both in organic and aqueous vehicles is the main concern in drug delivery because agglomeration affects properties of CNTs but their dispersibility can be improved by allowing simplistic operations to the processing of CNTs (Tangboriboon 2019); (v) functionalization enables CNTs to improve their dispersibility and provides a variety of functional groups for specific and selective conjugation of bioactive molecules, homing ligand, improves their biodistribution, exclusively enhances site specific targeting, and so on. Depending on the specific requirement, functionalization can be done either by covalent (chemical bond formation) or non-covalent (physioadsorption) method, respectively. Additionally, its exceptionally great surface area, chemical purity, and free π electrons make CNTs an ultimate vehicle for drug delivery (Merum et al.2017; Zhang et al.2018). As a significance of inimitable mechanical, electrical and structural variety, it gives greater strength, tractability and electrical conductivity en route for innumerable biological entities, which is convenient for biosensing, diagnosis, and disease treatment. CNTs depending on diameter, their lengths, and number of walls are broadly classified into four types: single-walled, double-walled, triple-walled, and multi-walled carbon nanotubes (Figure 1). Different techniques are used for the synthesis of CNTs. Properties of CNTs may vary which depend on the mechanism of method used (Mahajan et al.2018). Various techniques of synthesis, purification, functionalization, and characterization are depicted in Ishikawa fishbone diagram (Figure 2).