Abstract
Ischemic stroke continues to be a primary contributor to disability and mortality globally, with existing treatment options limited by their efficacy, restricted therapeutic window, and systemic adverse effects. In this study, multi-walled carbon nanotubes were synthesized using a chemical vapor deposition method. A ferrocene catalyst, 95% argon, balanced with 5% hydrogen at a temperature of 700 °C and a gas flow rate of 400 mL.min-1 was used to synthesize carbon nanotubes. The multi-walled carbon nanotubes (MWCNTs) were synthesized under varying reaction times to evaluate the impact on the yield and structural properties of the nanotubes. Following synthesis, the MWCNTs were carboxylated by treating them with a mixture of concentrated sulfuric acid and nitric acid in a 3:1 ratio, which facilitated the oxidation of the nanotube surface, resulting in the formation of carboxyl groups (-COOH), and acylated using thionyl chloride (SOCl₂) and dimethylformamide (DMF) in a 20:1 under reflux conditions. The purified multi-walled carbon nanotubes (MWCNTs) were further treated with polyethylene glycol (PEG) to improve biocompatibility and prolong their circulation time in the bloodstream. Thereafter, the pegylated MWCNTs were loaded with fluorescein isothiocyanate (FITC), methylprednisolone, and transferrin resulting in FITC-PSL-TFN-PEG-MWCNTs. FITC served as a fluorescent marker for monitoring the nanotubes, while methylprednisolone was integrated for its anti-inflammatory effects, and transferrin was added to enable targeted delivery to cells exhibiting transferrin receptors at the blood-brain barrier. Furthermore, the recombinant tissue plasminogen activator was encapsulated into platelets for attachment to the FITC-PSL-TFN-PEG-MWCNTs. Raw 264.7 cells were used to analyze the toxicity of pristine MWCNTs, PEG MWCNTs, and FITC-PSL-TFN-PEG-MWCNTs. The pristine MWCNTs were highly toxic to the raw 264.7 cells at lower to high concentrations, and PEG-MWCNTs and FITC-PSL-TFN-PEG-MWCNTs were found to be compatible with raw 264.7 cells, and their cell viability increased as concentrations decrease. The findings of this study suggest that PEG-MWCNTs and FITC-PSL-TFN-PEG-MWCNTs can be potentially used for developing a biohybrid drug delivery device for the treatment of ischemic stroke, and more research is required for conjugating recombinant tissue plasminogen activator into platelets and attaching to FITC-PSL-TFN-PEG-MWCNTs.