Functionalized carbon nanotubes and their promising applications in therapeutics and diagnostics

Carbon Nanotubes: Smart Drug/Gene Delivery Carriers

“…A high respect ratio and needle-like structure helps CNTs overcome such barriers. 20 Another CNT internalization pathway includes endocytosis which can be broken into five categories: 44 phagocytosis, pinocytosis (mainly micropinocytosis), clathrin-mediated endocytosis or receptor-mediated endocytosis, caveolinmediated endocytosis, and clathrin/caveolae independent. Phagocytosis is an endocytic pathway through which large particles (~1 μm) are taken up by cells.…”

“…45 The results from various researchers showed that cells may internalize CNTs up to 100 nm in size by caveolin-and clathrin-mediated endocytosis; however, larger-sized CNTs of more than 300 nm are taken up through macropinocytosis mechanisms. 7,20 In addition to the advantages of CNTs and their drug cargo entering cells, each mechanism has its drawbacks that need to be carefully considered (Table 3).…”

“…CNT functionalization is generally divided into two categories: covalent and non-covalent. Singh et al 20 in their research reported that coumarin-6 loaded d-alphatocopheryl polyethylene glycol 1000 succinate (TPGS) conjugated multi-walled carbon nanotubes (C6-CNTPC) and coumarin-6 loaded carboxylated MWCNT C6-CNA had higher uptake rates compared to free c6 in A549 cells after 24 h. This TPGS conjugated MWCNT showed a higher percentage of apoptotic cell death, higher cytotoxicity, higher efficiency treatment and safety than non-coated CNTs and docetaxel (DTX). They also showed that C6-CAN followed passive diffusion mechanisms to cross into cells, while C6-CNTPC was preferentially taken up via phagocytosis pathways.…”

“…14 In particular, one nanomaterial, carbon nanotubes (CNTs), has attracted incredible interest in the biomedical field due both to their promising properties (such as high surface area, needle-like structure, considerable strength, flexible interaction with cargo, high drug loading capacity, outstanding optical and electrical features, high stability, biocompatibility, and ability to release therapeutic agents at targeted sites) and negative properties (most notably, lack of biodegradability and toxicity). [15][16][17][18][19][20][21] However, despite some negative attributes of CNTs, they continue to show exemplary functions in medicine, specifically in drug delivery systems, [22][23][24][25] gene delivery and gene therapy, [26][27][28][29][30][31] bioimaging, 32,33 diagnostic applications, 18,20 biosensors, 20,34 and vaccine delivery 35 to just name a few. Table 1 shows some of the attractive features of CNTs in various biomedical applications.…”

Carbon nanotubes: functionalisation and their application in chemical sensors

“…3). 77 Further chemical reactions can be performed on these oxide groups to functionalise with groups such as amides, thiols, or other groups. [78][79][80] Balasubramanian and Burghard also had clustered the method of covalent functionalisation of SWCNTs that was accomplished through three different approaches, namely, thermally activated chemistry, electrochemical modication, and photochemical functionalisation.…”