Nur 'Izzati Mansor

Co-encapsulation of Nigella sativa oil and plasmid DNA for enhanced gene therapy of Alzheimer’s disease

Abstract Alzheimer disease involves genetic and non-genetic factors and hence it is rational to be treated with genetic and non-genetic therapeutic agents. Nigella sativa has multiple therapeutic properties including neuroregeneration. Nigella sativa oil (NSO) was encapsulated in PLGA nanoparticles and pDNA was loaded either by adsorption on chitosan-modified particles or encapsulation within PLGA nanoparticles. The particle size and zeta potential of NSO-pDNA-chitosan-PLGA nanoparticles were highly dependent on the medium and exhibited high burst release. Meanwhile, NSO-pDNA-PLGA nanoparticles were more consistent with lower burst release. The fabricated nanoparticles revealed the expected outcomes of both pDNA and NSO. The pDNA transfected N2a cell while the encapsulated NSO promoted neurite outgrowth that is crucial for neuroregeneration. Results from this study suggest that NSO could be added to the gene delivery carrier to enhance treatment benefits for Alzheimer disease.

Cellular uptake of Nigella sativa oil-PLGA microparticle by PC-12 cell line.

Abstract The aim of this study is to investigate the cell uptake of Nigella sativa oil (NSO)-PLGA microparticle by neuron-like PC-12 cells in comparison to surfactants; hydrophilic (Tween 80 & Triton X100) and hydrophobic (Span 80). Solvent evaporation was used to precisely control the size, zeta potential and morphology of the particle. The results revealed varying efficiencies of the cell uptake by PC-12 cells, which may be partially attributed to the surface hydrophobicity of the microparticles. Interestingly, the uptake efficiency of PC-12 cells was higher with the more hydrophilic microparticle. NSO microparticle showed evidence of being preferably internalised by mitotic cells. Tween 80 microparticle showed the highest cell uptake efficiency with a concentration-dependent pattern suggesting its use as uptake enhancer for non-scavenging cells. In conclusion, PC-12 cells can take up NSO-PLGA microparticle which may have potential in the treatment of neurodegenerative disease.

Method Development and Validation using UV Spectrophotometry for Nigella sativa Oil Microparticles Quantification

Nigella sativa oil (NSO) has been exploited for medical purposes for many generations. The fabrication of microparticles containing NSO intended for sustained release was done to be used in treating osteomyelitis. Method in quantifying NSO using UV-spectroscopy was developed and validated. Linearity shown a good correlation coefficient with the values higher than 0.995, both for actual and different analysts. The LOD and LOQ values were recorded to be 2.89 µg/mL and 8.75 µg/mL respectively. In addition, the highest %RSD values for the intermediate and repeatability studies were 0.970% and 0.445% which suggested the method was precise. The percentage recovery for 4 known concentrations gave the range between 98.16% to 99.39%, indicating the high accuracy of the method. The parameters analyzed in this study were in accordance with ICH Q2 (R1) guidelines.

Comparative assessment of plasmid DNA delivery by encapsulation within or adsorbed on poly (D, L-lactide-coglycolide) nanoparticles

Purpose : To compare the gene delivery effectiveness of plasmid DNA (pDNA) encapsulated within poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles with that adsorbed on PLGA nanoparticles. Methods: PLGA nanoparticles were prepared using solvent-evaporation method. To encapsulate pDNA within the particles, it was first complexed with cetyltrimethylammonium bromide (CTAB) and then added to the oil phase during the synthesis. For the adsorption, PLGA nanoparticles were first modified with either CTAB or chitosan and then pDNA was adsorbed on the particle surface by electrostatic interaction. Results : Nanoparticles encapsulating pDNA exhibited better plasmid loading and protection with significantly lower burst release (p < 0.05) compared to that of the nanoparticles with adsorbed plasmid. Cell uptake of chitosan-modified nanoparticles by murine neuroblastoma (N2a) cells was significantly (p < 0.05) higher than that of chitosan-free nanoparticles. Nanoparticles encapsulating pDNA showed higher transfection efficiency (p < 0.05) in N2a cells. Conclusion : Encapsulation of pDNA within PLGA nanoparticles presents a potential strategy for gene delivery that is superior to pDNA adsorbed on the nanoparticle surface. In addition, encapsulation keeps the particle surface free for further modifications such as the addition of targeting ligands. Keywords : Poly (D,L-lactide-co-glycolide), Plasmid DNA, Encapsulation, Adsorption, Cellular uptake, Gene therapy, Targeting ligands