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Naslov:EFFECT OF GELATINE SCAFFOLDS FABRICATION AS POLYPROPYLENE MESH COAT ON IMPLANT BIOCOMPATIBILITY
Avtorji:ID Gorgieva, Selestina (Avtor)
ID Kokol, Vanja (Mentor) Več o mentorju... Novo okno
ID Štrancar, Janez (Komentor)
Datoteke:.pdf DR_Gorgieva_Selestina_2014.pdf (4,98 MB)
MD5: A89A9DCC5AE3E6C8029FE7E7E9BD0D03
 
Jezik:Angleški jezik
Vrsta gradiva:Doktorska disertacija
Tipologija:2.08 - Doktorska disertacija
Organizacija:FS - Fakulteta za strojništvo
Opis:This work presents the methodological study, processing and optimization of novel, technologically acceptable procedure for in situ coating of polypropylene (PP) mesh (used for hernia treatment) with physico-chemically, mechanically and micro-structurally different gelatin (GEL) scaffolds to assess implant composite biocompatibility impact. In order to systematically follow the experimental work progress and respective achievements, whole research path is subdivided into three main sections. In the first section, the procedure for fabrication of gradiently micro-porous GELscaffolds on the cryo-unit’s cooling plate surface, using spatiotemporal and temperature- controlled gelation and freezing, followed by lyophylizaton was studied. Subsequently, cross-linking procedure using different molarities of reagents (EDC and NHS) and reaction media (100% PBS or 20/80% PBS/EtOH mixture) was performed for variable time extensions (1-24 h), rendering scaffolds physico-chemical properties. In this way, scaffolds with micro-structures having porosity gradient from 100 µm to 1000 µm and pores with rounded to ellipsoid morphology were formed, which, in combination with ethanol (EtOH) addition in cross-linking media modulates the swelling capacity towards twice lower percentages (~600%) comparing with scaffolds cross-linked in 100% PBS. Whilst the presence of EtOH reduce the cross-linking kinetic by retaining the scaffolds’ micro-structure formed during freezing, the 100% PBS and higher EDC molarity resulted in 40% cross-linking degree, being expressed as a thermal resistance up to 73 °C. The presented integral fabrication procedure was shown to allow tuning of both, the physical and micro-structural properties of scaffold, utilized in preparation of materials for specific biomedical applications. In the second part, the complex relation between surface and interface-related physico-chemical properties and gradient micro-structuring of 3D GELscaffolds, being fabricated by simultaneous temperature- controlled freeze-thawing cycles and in situ cross-linking using variable conditions (pH and molarity of carbodiimide reagent) and fibroblast cells viability (by tracking of their spreading and morphology) was established. Rarely- populated cells with rounded morphology and small elongations were observed on scaffolds with apparently negatively- charged surface with a lower cross-linking degree (CD) and consequently higher molecular mobility and availability of cell-recognition sequences, in comparison with the prominently- elongated and densely- populated cells on a scaffold’s with positively- charged surface, higher CD and lower mobility. Surface micro-structure effect was demonstrated by cell’s vacuolization and their pure inter-communication being present on scaffold’s bottom side with smaller pores (25±19 µm) and thinner pore walls (9±5 µm), over the air- exposed side with twice bigger pores (56±38 µm) and slightly thicker pore walls (12±6 µm). Strong correlation of preparation conditions (pH and reagents molarity) with CD (r2=0.96) and moderate correlation with local molecular mobility (r2 =-0.44), as well as micro-structure features being related to temperature gradient, imply on possibility to modulate scaffold’s properties in a direction to guide cell’s viability and most likely its genotype development. The third part presents an innovative strategy for the fabrication of bio-active PPmesh-GELscaffold composites with a potential for abdominal hernia treatment, where mesothelial cells in-growth have to be stimulated together with fibroblasts on-site proliferation, while formation of fibrin-developing, viscera-to-abdominal wall adhesions should be reduced, together with bacteria- related infections. In this respect, the plasma pre-activated PPmesh was coated with micro-structured GELscaffold, with pore size in 50 µm to 100 µm range at the upper-side and loosely- porous network at the composite bottom side, being modulated by sample thickness and freezing end- temperature applied. Simultaneously, the
Ključne besede:gelatin, targeted cross-linking, controlled freezing, gradiental micro-porosity, scaffold, surface and interface chemistry, physico-mechanical properties, polypropylene mesh, composite, biocompatibility.
Kraj izida:[Maribor
Založnik:S. Gorgieva]
Leto izida:2014
PID:20.500.12556/DKUM-43970 Novo okno
UDK:[544.777:678.742.3.06]:[606:61](043.3)
COBISS.SI-ID:17799702 Novo okno
NUK URN:URN:SI:UM:DK:RY7W343L
Datum objave v DKUM:07.05.2014
Število ogledov:2302
Število prenosov:169
Metapodatki:XML RDF-CHPDL DC-XML DC-RDF
Področja:KTFMB - FS
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Vaša ocena:Ocenjevanje je dovoljeno samo prijavljenim uporabnikom.
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Sekundarni jezik

Jezik:Slovenski jezik
Naslov:VPLIV IZDELAVE ŽELATINSKIH NOSILCEV KOT PREVLEK POLIPROPILENSKE MREŽE NA BIOKOMPATIBILNOST VSADKA
Opis:V doktorski disertaciji je predstavljena metodološka študija procesiranja in optimiranja novega, tehnološko sprejemljivega postopka za in sito oplaščanje polipropilenske mreže (PPmreže) (uporabne za zdravljenje poškodb hernije) s fizikalno- kemično, mehansko in mikro- strukturno različno formuliranim želatinskim nosilcem (GELnosilcem), ter ocenjen vpliv na biokompatibilnost kompozitnega vsadka. Zaradi lažjega sistematičnega spremljanja poteka eksperimentalnega dela in nastalih dosežkov, je disertacija razdeljena v tri sklope. V prvem delu je prikazan študij postopka izdelave gradientno mikro-poroznega GELnosilca na površini hladilne plošče s cryo-enoto, s pomočjo prostorno in časovno nadzorovane temperature geliranja in zamrzovanja ter naknadne liofilizacije. Z uporabo različnih molarnih koncentracij reagentov (EDC in NHS) in reakcijskih medijev (100 % PBS ali 20/80 % PBS/EtOH) ter variiranja časa trajanja reakcije (1-24 h) v postopku naknadnega zamreževanja je tako prikazan tudi vpliv le tega na spreminjanje fizikalno-kemijskih lastnosti nosilca. Takšen način je omogočil gradientno mikro-strukturiranje nosilcev s velikostjo por med 100 µm in 1000 µm ter krožno in/ali elipsoidno morfologijo por, ki v kombinaciji s dodatkom etanola (EtOH) v medij za zamreževanja modulirajo stopnjo nabrekanja, ki je bila tako dvakrat nižja (600%) v primerjavi nosilce zamrežene v 100% PBS. Medtem, ko je dodatek EtOH znižal kinetiko premreženja in ohranil mikro-strukturo formirano v fazi zamrzovanja, se je zamreževanje v 100 % PBS ob uporabi višje molarne koncentracije EDC povišalo na ~40%, kar je posledično zvišalo temperaturno stabilnost nosilca do ~73 °C. Preučen integralni postopek izdelave GELnosilcev se je izkazal za uporabnega z vidika spreminjanja njegovih fizikalno-kemijskih in mikro-strukturnih lastnosti in posledično v pripravi materialov za posebne biomedicinske aplikacije. V drugem delu je definirana kompleksna relacija med površinskimi in medfaznimi fizikalno- kemijskimi lastnostmi in gradientnim mikro-strukturiranjem GELnosilcev narejenih s hkratnim temperaturno-nadzorovanim ciklom zamrzovanja-taljenja in in sito zamreževanja s spreminjanjem pogojev (pH medija in molarne koncentracije EDC), na preživetje fibroblastnih celic s sledenjem njihove delitve in morfologije. Na navidezno negativno nabiti površini nosilca z nižjo stopnjo zamrežanja in posledično višji molekularni mobilnosti in dostopnosti celično-prepoznavnega aminokislinskega zaporedja je bila tako opažena redka poseljenost celic z okroglo morfologijo in malih raztezkov, v primerjavi z značilno podolgovatimi in gosto-poseljenimi celicami na pozitivno nabiti površini nosilca z višjo stopnjo zamrežanja ter nizko molekularno mobilnost. Vpliv površinske mikro-strukture nosilcev, prikazan z vakuolacijo celic in njihovo šibko medsebojno komunikacijo na (spodnji) strani nosilca z manjšimi porami (25±19 µm) in debelinami sten (9±5 µm) v primerjavi s stranjo nosilca izpostavljeno zraku z dvakrat večjimi porami (56±38 µm) in debeline sten (12±6 µm). Ugotovljena zelo močna korelacija med pogojev priprave (pH in molarno koncentracijo reagentov) in stopnjo zamrežanja (R2=0.96) in srednje močna s lokalno molekularno mobilnost (R2=-0.44), ter mikro–strukturiranje povezano s temperaturnim gradientom, je pokazala na možnost moduliranja lastnosti nosilcev v smeri usmerjanja sposobnosti preživetja celic in verjetno tudi razvoja njihovega genotipa. V tretjem delu je prikazan inovativni način izdelave bio-aktivnega kompozita (PPmreže-GELnosilec) s potencialno uporabo pri zdravljenja poškodb trebušne kile, kjer je potrebno spodbuditi rast mezotelijskih celic in proliferacijo fibroblastov na mestu poškodbe ter istočasno zmanjšati adhezijo abdominalne stene z notranjimi organi zaradi nastajanja fibrina in preprečiti nastanek bakterijsko-povezanih okužb. S tem namenom je bil preučen vpliv oplaščenja plazemsko pre-aktivirane PPmreže z mikro-strukturiranim GELnosilcem s gradientom poroznosti od uniformno
Ključne besede:želatina, ciljano mreženje, kontrolirano zamrzovanje, gradientna mikro-poroznost, nosilec, površinska in medfazna kemija, fizikalno-mehanske lastnosti, polipropilenska mreža, kompozit, biokompatibilnost.


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