Browsing by Author "Rubaka, Clarence"

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Chitosan-coated liposomes of Carrisa spinarum extract: synthesis, analysis and anti-pneumococcal potency
(ICE Publishing, 2023-02-16) Rubaka, Clarence; Gathirwa, Jeremiah; Malebo, Hamisi; Swai, Hulda; Sibuyi, Nicole; Hilonga, Askwar; Dube, Admire
In the present study, a chitosan (CS)-coated liposome (LipCsP-Chitosan) nanocarrier was fabricated for the delivery of Carissa spinarum (CsP) polyphenols to improve bioavailability and anti-pneumococcal potential against Klebsiella pneumoniae. LipCsP-Chitosan was synthesized by the ion gelation method and characterized by using a Malvern zetasizer and Fourier Transform Infrared (FTIR); CsP encapsulation and release kinetics were investigated. Anti-pneumococcal activity of the nanoformulations was accessed by agar-well diffusion and microdilution assays. LipCsP-chitosan exhibited a hydrodynamic size and zeta potential of 365.22 ± 0.70 nm and +39.30 ± 0.61 mV, respectively. CsP had an encapsulation efficiency of 81.5%. FTIR analysis revealed the interaction of the liposomes with chitosan and the CsP. A biphasic CsP release profile followed by a sustained release pattern was observed. LiPCsP-Chitosan presented a higher bioaccessibility of polyphenols in the simulated gastric phase (74.1% ± 1.3) than in the simulated intestinal phase (63.32% ± 1.00). LipCsP-chitosan had a relative inhibition zone diameter of 84.33% ± 2.51 when compared to CsP. At minimum inhibition concentration of 31.25 mg/mL, LipCsP-Chitosan reduced the viability of Klebsiella pneumoniae by 57.45% ± 3.76 after 24 h. The results obtained from the current study offer a new approach to the utilization of LipCsP-Chitosan as nanocarriers for candidate anti-pneumococcal agents.
Development and Characterization of Nanovesicles Containing Phenolic Compounds of Carissa spinarum: Encapsulation, Release Kinetics, Antimicrobial Activity and Mathematical Modeling
(Trans Tech Publications Ltd, 2023-05) Rubaka, Clarence; Gathirwa, Jeremiah; Malebo, Hamisi; Swai, Hulda; Hilonga, Askwar
The aim of this study was to develop and characterize a delivery system for polyphenols from an extract of Carissa spinarum leaves, based on liposomes. Liposomes loaded with Carissa spinarum polyphenols (nanoliposomal CsP) were prepared by ethanol-solvent injection method and characterized in terms of zeta potential, size, and polydipersity index by using Zeta sizer and Fourier Transform Infrared spectrum analysis. Total Phenolic content was measured by using Folin-Ciocalteu method and entrapment efficiency was evaluated. The release behavior was conducted in Phosphate Buffer Saline (PBS) solution at pH, 7.4 and Kinetic model fitted to evaluate mechanism of release. Disc diffusion sensitivity test was used to evaluate antimicrobial activity of free extract and nanoliposomal CsP. The mean diameter of nanoliposomal CsP was 181 ± 1.02 nm and had 0.345 ± 0.014 polydipersity index. Zeta potential value for nanoliposomal CsP was-45.6 ± 8.84 mV. Entrapment efficiency under the optimum conditions was 66.11 ± 1.11%. and the nanoliposomal CsP was stable over 30 days. The antibacterial activity of nanoliposomal CsP exhibited inhibition zone diameter of 14.33 ± 1.53 mm and 12.00 ± 1.23 mm against S. aureus and E. coli respectively The results reveal the Carrisa spinarum liposome can be applied as potential carrier for delivery of polyphenols to improves therapeutic action against bacterial strain.
Fabrication of liposome-chitosa N-ZnO nanohybrid integrated with Carissa Spinarum extract for antibacterial application
(NM-AIST, 2023-08) Rubaka, Clarence
Innovative biomaterials provide a stimulating and adaptable platform for the implementation of new and more effective methods to prevent bacterial infection. Built on biomimetic inorganic hybrid material, Dual Nanohybrid Delivery System (DN-DS) has advantageous properties for biomedical applications, such as the delivery of herbal formulations for the treatment of bacterial infections. Using microwave assisted extraction (MAE), the polyphenols of Carissa spinarum were extracted. The Dual Nanohybrid Delivery System (LipCsP-ZnONPs)-CT was formed by combining LipCsP-Chitosan and ZnO-Chitosan, which were both generated using different methods of co-precipitation and ion gelation, respectively. A Zetasizer was used to characterize the nanosystems' size, zeta potential, and polydispersity index (PDI). A UV-visible spectrophotometer was utilized for the optical study, and a scanning electron microscope was employed to investigate at the surface morphology. The interaction of coated chitosan with liposomes and ZnONPs was evaluated using Fourier Transformation Infrared (FTIR) spectroscopy. Different kinetic models were fitted to the results of the encapsulation and release profiles of polyphenols in the liposome nanosystems to determine the mechanism of release. Antibacterial activity of the nanoformulations was assessed by an agar diffusion assayand the micro plate blue assay (MABA). The Zeta potential of LipCsP changed from -45.3 ± 0.78 to +34.43 ±1.36 due to chitosan coatings. Polyphenol-encapsulation efficiency was higher in LipCsP-Chitosan (81 ± 2.5%) than in LipCsP (66.11 ± 1.11%). Conversely, the size of LipCsP (176.17 ± 1.05 nm) increasedto 365.2 ± 0.70 nm. FTIR analysis revealed the interaction of the liposome with chitosan due to the disappearance of N-H primary amine. Interaction between chitosan and zinc oxide was revealed by the formation of new absorption peaks at 670 cm-1 and 465 cm-1 as observed in the FTIR analysis. (LipCsP-ZnONPs)-CT presented high bioaccessibility of polyphenols in the simulated gastric phase (82.14 ± 0.80%) than in simulated intestinal phase (71.60 ± 0.86%), a stable system for sustained release of polyphenols, and prominent antibacterial activity. (LipCsP-ZnONPs)-CT exhibited a relative inhibition zone diameter (RIZD) of 89.60 ± 1.32, significant high viability reduction (P˂0.05) against Klebsiella pneumoniae as compared to LipCsP-Chitosan and ZnO-chitosan. The nanohybrid systems (LipCsP-Chitosan and ZnO chitosan) exhibited synergistic effect against Klebsiella pneumoniae. This study successfully demonstrated the utility of the nanohybrid as a potential antibacterial agent against K. ii pneumoniae, therefore, the fabricated dual nano delivery system is an efficacy material for treatment of pneumococcal infections.
Fabrication of liposome-chitosan-zno nanohybrid integrated with Carissa Spinarum extract for antibacterial application
(NM-AIST, 2023-08) Rubaka, Clarence
Innovative biomaterials provide a stimulating and adaptable platform for the implementation of new and more effective methods to prevent bacterial infection. Built on biomimetic- inorganic hybrid material, Dual Nanohybrid Delivery System (DN-DS) has advantageous properties for biomedical applications, such as the delivery of herbal formulations for the treatment of bacterial infections. Using microwave assisted extraction (MAE), the polyphenols of Carissa spinarum were extracted. The Dual Nanohybrid Delivery System (LipCsP-ZnONPs)-CT was formed by combining LipCsP-Chitosan and ZnO-Chitosan, which were both generated using different methods of co-precipitation and ion gelation, respectively. A Zetasizer was used to characterize the nanosystems' size, zeta potential, and polydispersity index (PDI). A UV-visible spectrophotometer was utilized for the optical study, and a scanning electron microscope was employed to investigate at the surface morphology. The interaction of coated chitosan with liposomes and ZnONPs was evaluated using Fourier Transformation Infrared (FTIR) spectroscopy. Different kinetic models were fitted to the results of the encapsulation and release profiles of polyphenols in the liposome nanosystems to determine the mechanism of release. Antibacterial activity of the nanoformulations was assessed by an agar diffusion assayand the micro plate blue assay (MABA). The Zeta potential of LipCsP changed from -45.3 ± 0.78 to +34.43 ±1.36 due to chitosan coatings. Polyphenol-encapsulation efficiency was higher in LipCsP-Chitosan (81 ± 2.5%) than in LipCsP (66.11 ± 1.11%). Conversely, the size of LipCsP (176.17 ± 1.05 nm) increasedto 365.2 ± 0.70 nm. FTIR analysis revealed the interaction of the liposome with chitosan due to the disappearance of N-H primary amine. Interaction between chitosan and zinc oxide was revealed by the formation of new absorption peaks at 670 cm-1 and 465 cm-1 as observed in the FTIR analysis. (LipCsP-ZnONPs)-CT presented high bioaccessibility of polyphenols in the simulated gastric phase (82.14 ± 0.80%) than in simulated intestinal phase (71.60 ± 0.86%), a stable system for sustained release of polyphenols, and prominent antibacterial activity. (LipCsP-ZnONPs)-CT exhibited a relative inhibition zone diameter (RIZD) of 89.60 ± 1.32, significant high viability reduction (P˂0.05) against Klebsiella pneumoniae as compared to LipCsP-Chitosan and ZnO-chitosan. The nanohybrid systems (LipCsP-Chitosan and ZnO- chitosan) exhibited synergistic effect against Klebsiella pneumoniae. This study successfully demonstrated the utility of the nanohybrid as a potential antibacterial agent against K.pneumoniae, therefore, the fabricated dual nano delivery system is an efficacy material for treatment of pneumococcal infections.
Inorganic Nanocarriers: Surface Functionalization, Delivery Utility for Natural Therapeutics - A Review
(Scientific.Net, 2022-08) Rubaka, Clarence; Gathirwa, Jeremiah; Malebo, Hamisi; Swai, Hulda; Hilonga, Askwar
Inorganic nanocarriers for a decade have increased interest in nanotechnology research platform as versatile drug delivery materials. The utility of the inorganic nanocarriers for delivery of therapeutic agents is attributed to their unique properties such as magnetic, photocatalytic nature and the ability to exhibit surface functionalization. Herein, we review the surface functionalization and delivery utility for natural therapeutics exhibited by inorganic nanocarriers mostly focusing on their magnetic, photocatalytic and the plasmonic properties. The review also highlights the influence of electronic property of inorganic surface on functionalization of ligand based natural therapeutic agents. Improvement of stability and therapeutic potential by formation of nanocomposites are detailed. Furthermore, we suggest improvement strategies for stability and toxicity reduction of inorganic nanoparticles that would potentially make them useful for clinical application as therapeutic delivery tools for treatment of various diseases.