Banca de DEFESA: EDMO HENRIQUE MARTINS CAVALCANTE

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : EDMO HENRIQUE MARTINS CAVALCANTE
DATE: 09/12/2022
TIME: 09:00
LOCAL: google meet
TITLE:
CHITOSAN AND MAGNETITE BASED COMPOUNDS FOR DNA ADSORPTION  AND APPLICATIONS IN ZnO-MODIFIED
 ANTIBACTERIALS.

KEY WORDS:

biotechnology, adsorption, electrospinning, decontamination, wound dressing.


PAGES: 161
BIG AREA: Outra
AREA: Multidisciplinar
SUBÁREA: Biotecnologia
SUMMARY:

The isolation of nucleic acids, a step that precedes several biochemical and diagnostic processes, is time consuming, whereas the growing demand for genomic analysis requires the development of alternative systems for biomolecule extraction. Magnetic separation of DNA has aroused more interest because it allows its extraction from complex media by using a suitable buffer system. However, these media can include antibiotic resistance genes that are overlooked as a pollutant in contaminated effluents and fluids, which favors the emergence of resistant strains. These pathogenic organisms, although structurally simple, have a highly plastic genome, which contributes to their diversification and adaptation through the dissemination of resistance, virulence, and metabolic pathways genes. In this work, Eudragit E-100®/poly(ethylene oxide)@Fe3O4 and chitosan-functionalized magnetite nanoparticles were produced for DNA adsorption. The diameters of electrospun fibers presented bimodal distribution, forming a non-compacted and resistant scaffold subjected to wicking. The fiber adsorption process was explained by the Freundich isotherm (R2 = 98.9%), with a maximum
capacity of 55.14 mg.g-1 obtained experimentally. The pseudo-second-order kinetic model was the one that best characterizes the systems, affected by availability of active sites in relation to analyte concentration and the driving force for mass transfer. The mapping of iron and phosphorus by dispersive energy spectroscopy of fibers with adsorbed DNA showed a correlation between the dispersions of both elements in the material, indicating that the presence of magnetite favored the removal of DNA from the solution. The porous nature of the material led to the Weber-Morris intraparticle diffusion model, which showed the multiple nature of the observations: the diffusion of DNA in the boundary layer and inside the fiber. Magnetite produced by ultrasonic bath in alkaline medium and functionalized with chitosan had a higher adsorption capacity, calculated at 80.26 mg.g-1 using the Langmuir model (R2 = 99.87%). Both platforms have a simple synthesis process, without the use of toxic volatile compounds. In the functionalization of those nanoparticles, the use of chitosan was also advantageous because it was easily dispersed and conveniently recovered with the aid of an external magnet. In due course, this natural and abundant biopolymer was used in the production of antibacterial compounds against Staphylococcus aureus (ATCC 25923). Materials based on chitosan and zinc oxide in the form of membranes and incorporated in Nile tilapia (Oreochromis niloticus) skin showed mechanisms that reduced the time of death due to the stabilizing action of chitosan on metallic oxide. The PVA-chitosan-ZnO membranes produced higher inhibition halos, whereas, among the modified tilapia skins, the one containing chitosan presented a higher as a result of the reduction of the molar mass of the polymer during skin preparation. In addition, these materials satisfactorily inhibited the formation of the S. aureus biofilm and may be indicated in cases where reepithelialization and healing are delayed due to the presence of this microorganism in chronic wounds. Therefore, chitosan has been shown to be an alternative to conventional antimicrobials when interacting with the bacterial cell envelope leading to the extravasation of cytosolic material, while it can be applied in the removal of dispersed DNA in the medium.


BANKING MEMBERS:
Externa à Instituição - LEDA MARIA SARAGIOTTO COLPINI - UFPR
Externo à Instituição - RAIMUNDO CAMPOS PALHETA JÚNIOR - UNIVASF
Externo à Instituição - RICARDO SANTANA DE LIMA - UNIVASF
Interno - ***.928.554-** - HELINANDO PEQUENO DE OLIVEIRA - UNIVASF
Interno - ***.979.560-** - MATEUS MATIUZZI DA COSTA - UFSM
Notícia cadastrada em: 09/11/2022 09:17
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