Diagnosis and Treatment of Neurological and Ischemic Disorders Employing Carbon Nanotube Technology

Table 2

Functionalized carbon nanotubes and reduced cytotoxic effects. Different functional groups on MWCNTs and SWCNTs have different toxic effects on different cell types and animal types.

Functional group or structure	Toxicological studies	Application	Target site	Reference
Acid-oxidized SWCNTs	Apoptosis studies showed no apparent cell toxicity	Intracellular protein transporters	Mammalian cells	Kagan et al., 2010 [52]
Acid-treated, water-soluble SWCNTs	No changes in cell viability or structure in lysosomes and cytoplasm		Human monocyte-derived macrophage cells	Keefer et al., 2008 [56]
Purified COOH-SWCNTs	No cytotoxicity	Pharmacological applications	Cultured mammalian cells	Al-Jamal et al., 2012 [57]
Oxidized ultrashort SWCNTs	Showed no cytotoxic effects	Intracellular delivery of oligonucleotide molecules	Human macrophages	Cellot et al., 2009 [58]
Amine-terminated CNTs	Cross cellular membrane without cytotoxicity	Delivery of amino acids, peptides, nucleic acids, or drugs		Webster et al., 2013 [59]; Shein et al., 2009 [60]; He and Dai, 2004 [61]
SWCNT-PL-PEG	Gene silencing with no apparent cytotoxic effects	SH-small interfering RNA delivery	Human T cells	Modi et al., 2010 [2]
SWCNT-PEG-drug	Decreased reactive oxygen species mediated toxicological response and exhibited less cytotoxicity	Drug delivery	Neuronal PC12 cells	Grossman and Broderick, 2013 [10]
SWCNT-PEG-cisplatin/doxorubicin	Remarkable reduction of cytotoxicity	Drug delivery and imaging tool	Human cancer cells/mice	Sharma et al., 2013 [62]; Ansari et al., 2011 [19]
SWCNT-PEG-mAb (αvβ3)	Without harming adjacent normal cells	Cancer-cell targeting	αvβ3-positive U87MG cells	Tan et al., 2012 [63]
SWCNT-PEG	Revealed no evidence of toxicity over 4 months	Mice		Kotchey et al., 2013 [64]
MWNT-CS-(PC)	Chitosan and PC reduced the cytotoxic effects on normal cells with specific photo-induced toxicity towards malignant cells	Photothermal therapy	MCF-7, HepG2, L-O2 cell lines	John et al., 2015 [65]
Polyoxyethylene sorbitan monooleate (PS80) CNTs	Suppressed cytotoxicity		Human lung mesothelium cells (MSTO-211-H)	Zheng et al., 2003 [50]
HMDA-SWCNTs; PDDA chloride-SWCNTs	Negligible cytotoxic effects	Intracellular delivery of negatively charged biomolecules	Rat heart cells	Pardridge, 2012 [66]
SWCNTs with human serum proteins	Blood proteins altered SWCNT cellular interaction pathways and reduced cytotoxicity	Biological applications	Human acute monocytic leukemia cell lines and human umbilical vein endothelial cells	Ciccone et al., 2011 [16]
BSA-dispersed SWCNTs	No acute deleterious cellular effects		Human mesenchymal stem cells and HeLa cells	Ben-Jacob and Hanein, 2008 [67]
Albumin-SWCNTs	Induced cyclooxygenase-2 and modulating toxicity effects of SWCNTs		RAW264.7 macrophage cell lines	Malarkey et al., 2009 [68]
DNA-encased MWCNTs	Does not exert cytotoxic effect on lymphocytes	Selective thermal ablation of malignant tissue in vivo	In vivo	Vidu et al., 2014 [69]
Lectin-functionalized CNTs	Increase in cell viability without signs of apoptosis	Nanovaccine fabrication	J774A macrophage (MOs) cell line	Kesharwani et al., 2012 [70]
Fluorescent CNT-FITC/biotin conjugates	Reduced cytotoxicity	Delivery systems	HL60 cells	Nho et al., 2010 [71]
Cationic fCNTs	Lowered cytotoxicity in vitro	Delivery of drugs and biomolecules	CHO, 3T3 fibroblast, Jurkat, HL60 cell lines	Kim et al., 2012 [72]

Adapted from Vardharajula et al. 2012 [73].
CNTs = carbon nanotubes; fCNTs = functionalized carbon nanotubes; SWCNTs = single-walled carbon nanotubes; PL = phospholipid; PEG = poly(ethylene glycol); mAb = monoclonal antibody; MWCNTs = multiwalled carbon nanotubes; CS = chitosan; PC = phycocyanin; CTAB = cetyltrimethylammonium bromide; HMDA = hexamethylenediamine; PDDA = polydiallyldimethylammonium; BSA = bovine serum albumin.