Browsing by Author "Ciro, Yhors"
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Item Biopolymers as a Potential Alternative for the Retention of Pollutants from Vinasse: An In Silico Approach(MDPI, 2024) Aristizabal, Yesid; Ciro, Yhors; Liscano, Yamil; Salamanca, Constain H.; Oñate Garzón, JoseVinasse, a waste from the bioethanol industry, presents a crucial environmental challenge due to its high organic matter content, which is difficult to biodegrade. Currently, no sustainable alternatives are available for treating the amount of vinasse generated. Conversely, biopolymers such as cellulose, carboxymethylcellulose, and chitosan are emerging as an interesting alternative for vinasse control due to their flocculating capacity against several organic compounds. This study seeks to determine the thermodynamic behavior of in silico interactions among three biopolymers (cellulose, carboxymethylcellulose, and chitosan) regarding 15 organic compounds found in vinasse. For this, the Particle Mesh Ewald (PME) method was used in association with the Verlet cutoff scheme, wherein the Gibbs free energy (ΔG) was calculated over a 50 ns simulation period. The findings revealed that cellulose showed a strong affinity for flavonoids like cyanidin, with a maximum free energy of −84 kJ/mol and a minimum of −55 kJ/mol observed with phenolic acids and other flavonoids. In contrast, chitosan displayed the highest interactions with phenolic acids, such as gallic acid, reaching −590 kJ/mol. However, with 3-methoxy-4-hydroxyphenyl glycol (MHPG), it reached an energy of −70 kJ/mol. The interaction energy for flavonoid ranged from −105 to −96 kJ/mol. Finally, carboxymethylcellulose (CMC) demonstrated an interaction energy with isoquercetin of −238 kJ/mol, while interactions with other flavonoids were almost negligible. Alternatively, CMC exhibited an interaction energy of −124 kJ/mol with MHPG, while it was less favorable with other phenolic acids with minimal interactions. These results suggest that there are favorable interactions for the interfacial sorption of vinasse contaminants onto biopolymers, indicating their potential for use in the removal of contaminants from the effluents of the bioethanol industry.Item Contribución antimicrobiana de colistina encapsulada en liposomas recubiertos con Quitosano de alto peso molecular (QHPM) frente a bacterias Gram negativas(Universidad Santiago de Cali, 2023) Cardona Hoyos, Ana Sofía; Salazar Guerra, Mayra Alejandra; Oñate Garzón, José Fernando; Ciro, YhorsPseudomonas aeruginosa is a Gram negative bacterium, which is not considered part of the human microbiota, so it has the ability to adapt to different environmental conditions due to its intrinsic resistance mechanisms to different antibiotics. This pathogen can colonize hospital environments, such as mechanical ventilators, catheters, among others. P. aeruginosa is of great importance worldwide as it is the main pathogen that causes infections in intensive care unit (ICU) patients. This makes it a public health problem since it has shown resistance to antibiotics such as colistin. The purpose of this study is to develop nanoliposomes functionalized with colistin-containing polymers to address the bacterial resistance of Pseudomonas aeruginosa. The method consists of the encapsulation of colistin within nanoliposomes superficially modified with high molecular weight chitosan (QHPM) to subsequently perform physicochemical characterization of the liposomes, where the particle size and zeta potential will be determined using a Zetasizer nano ZSP; The liposomes were characterized using dynamic light scattering and zeta potential where both parameters were observed to fluctuate in relation to polymer coating. Finally, the antimicrobial activity of colistin transported within the nanosystems was evaluated. Which the registered results were promising against isolated resistant Pseudomonas aeruginosa since it was possible to obtain a decrease in the MIC from 4 µg/mL to 2 µg/mL. However, more research is needed to determine the safety and efficacy of this strategy in humansItem Synthesis, characterisation and biological evaluation of ampicillin-chitosan-polyanion nanoparticles produced by ionic gelation and polyelectrolyte complexation assisted by high-intensity sonication(MDPI AG, 2019-10-21) Ciro, Yhors; Rojas, John; Oñate Garzon, Jose; Salamanca, Constain H.Recently, one of the promising strategies to fight sensitive and resistant bacteria, and decrease the morbidity and mortality rates due to non-nosocomial infections, is to use antibiotic-loaded nanoparticles. In this study, ampicillin-loaded chitosan–polyanion nanoparticles were produced through the techniques of ionic gelation and polyelectrolyte complexation assisted by high-intensity sonication, using several crosslinking agents, including phytic acid (non-polymeric polyanion), sodium and potassium salts of poly(maleic acid-alt-ethylene) and poly(maleic acid-alt-octadecene) (polymeric polyanions). These nanoparticles were analysed and characterised in terms of particle size, polydispersity index, zeta potential and encapsulation efficiency. The stability of these nanosystems was carried out at temperatures of 4 and 40 °C, and the antimicrobial effect was determined by the broth microdilution method using sensitive and resistant Staphylococcus aureus strains. The results reveal that most of the nanosystems have sizes <220 nm, positive zeta potential values and a monodisperse population, except for the nanoparticles crosslinked with PAM-18 polyanions. The nanometric systems exhibited adequate stability preventing aggregation and revealed a two-fold increase in antimicrobial activity when compared with free ampicillin. This study demonstrates the potential application of synthesised nanoparticles in the field of medicine, especially for treating infections caused by pathogenic S. aureus strains.Item Synthesis, Characterization, and Biological Evaluation of Chitosan Nanoparticles Cross-Linked with Phytic Acid and Loaded with Colistin against Extensively Drug-Resistant Bacteria(MDPI, 2024) Pacheco, Fabian; Barrera, Alejandro; Ciro, Yhors; Polo Cerón, Dorian; Salamanca, Constain H.; Oñate Garzón, JoséThe natural evolution of microorganisms, as well as the inappropriate use of medicines, have accelerated the problem of drug resistance to many of the antibiotics employed today. Colistin, a lipopeptide antibiotic used as a last resort against multi-resistant strains, has also begun to present these challenges. Therefore, this study was focused on establishing whether colistin associated with chitosan nanoparticles could improve its antibiotic activity on an extremely resistant clinical isolate of Pseudomonas aeruginosa, which is a clinically relevant Gram-negative bacterium. For this aim, nanoparticulate systems based on phytic acid cross-linked chitosan and loaded with colistin were prepared by the ionic gelation method. The characterization included particle size, polydispersity index-PDI, and zeta potential measurements, as well as thermal (DSC) and spectrophotometric (FTIR) analysis. Encapsulation efficiency was assessed by the bicinchoninic acid (BCA) method, while the antimicrobial evaluation was made following the CLSI guidelines. The results showed that colistin-loaded nanoparticles were monodispersed (PDI = 0.196) with a particle size of around 266 nm and a positive zeta potential (+33.5 mV), and were able to associate with around 65.8% of colistin and decrease the minimum inhibitory concentration from 16 μg/mL to 4 μg/mL. These results suggest that the association of antibiotics with nanostructured systems could be an interesting alternative to recover the antimicrobial activity on resistant strains.