Functionalized, Vertically Super-Aligned Multiwalled Carbon Nanotubes for Potential Biomedical Applications

Abstract

Currently, there is a lack of ultrasensitive diagnostic tool to detect some diseases such as ischemic stroke, thereby impacting effective and efficient intervention for such diseases at an embryonic stage. In addition to the lack of proper detection of the neurological diseases, there is also a challenge in the treatment of these diseases. Carbon nanotubes have a potential to be employed in solving the theragnostic challenges in those diseases. In this study, carbon nanotubes were successfully synthesized for potential application in the detection and treatment of the neurological diseases such as ischemic stroke. Vertically aligned multiwalled carbon nanotubes (VA-MWCNTs) were purified with HCl, carboxylated with H2SO4:HNO3 (3:1) and acylated with SOCl2 for use in potential targeting studies and for the design of a carbon-based electrode for possible application in the diagnosis of neurological diseases, including ischemic stroke. MWCNTs were washed, extracted from the filter membranes and dried in a vacuum oven at 60 °C for 24 h prior to functionalization and PEGylation. CNTs were characterized by SEM, TEM, OCA, DLS, CV and EIS. The HCl-treated CNT obtained showed an internal diameter, outer diameter and thickness of 8 nm, 34 nm and 75 µm, while these parameters for the H2SO4-HNO3-treated CNT were 8 nm, 23 nm and 41µm, respectively. PEGylated CNT demonstrated zeta potential, polydispersive index and particle size distribution of 6 mV, 0.41 and 98 nm, respectively. VA-MWCNTs from quartz tube were successfully purified, carboxylated, acylated and PEGylated for potential functionalization for use in targeting studies. For designing the carbon-based electrode, VA-MWCNTs on silicon wafer were successfully incorporated into epoxy resin for diagnostic applications. Functionalized MWCNTs were nontoxic towards PC-12 neuronal cells. In conclusion, vertically super-aligned MWCNTs have been successfully synthesized and functionalized for possible theragnostic biomedical applications in neurological disorders such as ischemic stroke.

Atrial Natriuretic Peptide Antibody-Functionalised, PEGylated Multiwalled Carbon Nanotubes for Targeted Ischemic Stroke Intervention

“…The DSPE-PEG5000-4-arm (PEG-amine) was synthesised by reacting DSPE-PEG5000 amine with 4-arm (PEG- amine) [ 25 ] in order to increase the branches to make it more reactive ( Scheme 1 ). Dexamethasone was thiolated using 2-iminothiolane to enhance its conjugation with PEGylated CNTs [ 14 ]. FITC was reacted with PEG-CNTs to attach it to the surface of the CNTs via π-π interactions and to conjugate it to the PEG-CNTs via PEG chains [ 18 ].…”

“…Acylated MWCNTs (0.2 mg/mL) were sonicated with 0.2 mM DSPE PEG5000-4-arm (PEG-amine) for 1 h ( Chart 1 ). The product was centrifuged at 24,000× g for 6 h using a Centrofriger-BL11 centrifuge (JP-Selecta, Abrera, Barcelona, Spain), and the supernatant was collected for characterization and further use [ 14 ].…”

“…CNTs have ultralow density and high specific surface area. They are non-immunogenic, non-toxic, biocompatible, photostable, cell membrane penetrable, and their size is alterable [ 14 ]. Carbon nanotubes possess three important unique features namely high specific surface area, ultralow density, and hollow central cavity for enabling the conjugation and encapsulation of therapeutics.…”

Nanoparticles in traumatic spinal cord injury: therapy and diagnosis

“…They are also non-immunogenic, nontoxic, photostable, ultra-lightweight and biocompatible. 91 CNTs possess excellent electrical and mechanical properties, such as neutral electrostatic potential, extremely high drug cargo ability, ultimate electrical and thermal conductivities making them an attractive tool for biomedical applications which is useful in the detection and treatment of neurological diseases. 89,91 Due to their various thermal, optical, electrical, mechanical and chemical characteristics, CNTs have potential applications in different fields of nanomedicine, drug delivery, biosensors, energy storage and neural prosthetics.…”

Carbon-Based Nanomaterials

“…CNTs are suitable candidates to be employed in solving the theragnostic challenges associated with neurological diseases such as ischemic stroke. In this regard, Komane et al [ 3 ] recently synthesized vertically aligned multiwalled carbon nanotubes (VA-MWCNTs), which were purified, carboxylated, acylated, and PEGylated, for use in targeting studies. The functionalized VA-MWCNTs were found to be nontoxic towards PC-12 neuronal cells, a type of catecholamine cell that synthesizes, stores, and releases norepinephrine and dopamine.…”