diplomsko delo
Ula Dolenc (Author), Miha Fošnarič (Reviewer), Klemen Bohinc (Mentor), Andrijana Sever Škapin (Co-mentor)

Abstract

Uvod: Adhezija bakterij predstavlja fizikalno-kemijski postopek, do katerega pride, ko se celice (bakterije) vežejo na substrat. Zaradi pritrditve bakterij na medicinske pripomočke in vsadke se pojavijo številne okužbe, ki so za človeka lahko nevarne. S premazovanjem površin lahko zmanjšamo bakterijsko adhezijo in posledično nastajanje biofilma. Namen: Namen diplomskega dela je bil spremeniti površino nerjavnega jekla AISI 316 s premazovanjem z različnimi premazi, ter ugotoviti vpliv premazovanja na adhezijo bakterij Pseudomonas aeruginosa. Metode dela: V diplomskem delu sta bili uporabljeni deskriptivna in raziskovalna metoda. Za raziskavo smo uporabili elektropolirane ploščice nerjavnega jekla AISI 316 v velikosti 10 mm × 10 mm, ki smo jih premazali s premazi Funcosil AG, Funcosil SNL ter Si-QAC. Ploščice brez in s premazi smo izpostavili bakterijski kulturi Pseudomonas aeruginosa. Ob začetnem času t0 in po dvajsetih urah inkubacije (t20) smo na ploščicah ugotavljali prisotnost bakterij z barvanjema s kristal vijoličnim barvilom, jodo-nitro-tetrazolijevim kloridom in sonikacijo. Vsem štirim skupinam ploščic smo izmerili mejne kote in hrapavost površin. Ploščice z bakterijsko kulturo, namenjene preiskavi z vrstičnim elektronskim mikroskopom smo naparili z ogljikom in ocenili število pritrjenih bakterij. Rezultati: Ploščice brez premaza so imele najmanj hrapavo površino. Za najbolj hrapavo površino pa so se izkazale ploščice s premazom Funcosil AG. Najmanjši mejni kot (82,6°) smo izmerili na ploščicah brez premaza, sledile so ploščice s premazom Si-QAC, kjer je mejni kot znašal 92,8°. Še večji mejni kot (105,7°) smo izmerili na ploščicah s premazom Funcosil SNL, največji kot pa je bil izmerjen na ploščicah s premazom Funcosil AG (111,5°). Vsi trije premazi so se tako izkazali za hidrofobne. Pri analizi z vrstičnim elektronskim mikroskopom so bile bakterije ob času t0 in t20 vidne samo na ploščicah s premazom Si-QAC, na ostalih skupinah ploščic ni bilo bakterij. Povprečno število živih bakterij pridobljeno s štetjem kolonijskih enot (CFU) je bilo ob času t0 in času t20 manjše na premazanih ploščicah, v primerjavi z nepremazanimi. Povprečno število bakterij po barvanju s kristal vijoličnim barvilom, ki prikazuje tako žive kot tudi mrtve bakterije, pa je bilo večje na premazanih ploščicah. Razprava in zaključek: Dokazali smo, da premazi vplivajo na adhezijo in preživetje bakterij na površinah.

Keywords

diplomska dela;ortotika in protetika;adhezija;nerjavno jeklo;bakterije;Pseudomonas aeruginosa;hidrofobnost;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL ZF - University College of Health Studies
Publisher: [U. Dolenc]
UDC: 617.3
COBISS: 79054083 Link will open in a new window
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Downloads: 59
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Other data

Secondary language: English
Secondary title: Adhesion of Pseudomonas aeruginosa to various stainless steel
Secondary abstract: Introduction: Bacterial adhesion represents a physicochemical process which occurs when cells (bacteria) are bound to the substrate. Bacteria attached to medical devices and implants may cause many infections that can be dangerous to humans. By coating surfaces bacterial adhesion and consequent biofilm formation can be reduced. Purpose: The purpose of this thesis is to change the surface of stainless steel AISI 316 by coating with different coatings and to determine the effect of coating on bacterial adhesion Psudomonas aeruginosa. Working methods: In diploma thesis a descriptive and a research method were used. For the research we used electropolishing tiles of stainless steel AISI 316 in size 10 mm × 10 mm, which we coated with coating Funcosil AG, Funcosil SNL and Si-QAC. Both tiles, coated and non-coated, were exposed to the bacterial culture Pseudomonas aeruginosa. At time t0 and after twenty hours of incubation (t20), we detected the presence of bacteria on surfaces by dyeing with crystal violet dye, iodo-nitro-tetrazolium chloride and sonication. Contact angles and surface roughness were measured for all four tiles groups. Tiles with bacterial culture intended for analysis by Scanning Electron Microscope were evaporated with carbon, analysed and the number of attached bacteria was estimated. Results: Uncoated tiles have the least rough surface. Funcosil AG-coated tiles proved the roughest surface. The minimum limit angle (82,6°) was measured in uncoated tiles, followed by SI-QAC coated tiles, where the limit angle was 92.8°. An even higher limit angle (105,7°) was measured in Funcosil SNL-coated tiles and the highest angle was measured on Funcosil AG-coated tiles (111,5°). All three coatings thus proved to be hydrophobic. With the Scanning Electron Microscope analysis, bacteria were visible at time t0 and t20 only on Si-QAC-coated tiles, no bacteria were present on the other groups of tiles. The average number of live bacteria obtained by colony counting units (CFU) was lower at time t0 and time t20 on coated tiles compared to uncoated tiles. The average number of bacteria after staining with crystal violet dye, showing both live and dead bacteria, was higher on the coated tiles. Discussion and conclusion: We proved that coatings affect bacterial adhesion and survival on surfaces.
Secondary keywords: diploma theses;orthotics and prosthetics;adhesion;stainless steel;bacteria;Pseudomonas aeruginosa;hydrophobicity;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Zdravstvena fak., Oddelek za protetiko
Pages: 39 str.
ID: 13627856