Vpliv adsorpcije na sproščanje proteinov iz alginatnih in nanoceluloznih hidrogelov

Mulec, Alexander Marjan (author), Ručigaj, Aleš (mentor)

Biopolimeri so skupina raznih proteinov, nukleotidov, maščob in polisaharidov, ki nastanejo v mnogih organizmih tekom metabolizma. Uporabni so predvsem zaradi svoje nizke cene, obnovljivosti ter zlasti biorazgradljivosti in biokompatibilnosti. Slednji dve lastnosti jih delata obetavne na področjih medicine in farmacije. Iz mnogih biopolimerov je možno pripraviti hidrogele, to so zamrežene tridimenzionalne strukture, ki so sposobne absorbirati vodo in nabrekniti, ne da bi ob tem izgubile svojo strukturo. Uporabnost hidrogelov zajema mnogo področij in aplikacij, med njimi izstopa uporaba v farmaciji kot nosilci za (kontrolirano) sproščanje učinkovin. V tem magistrskem delu sta bila pripravljena hidrogela iz alginata in TEMPO-oksidirane nanoceluloze za namen določitve vpliva adsorpcije na sproščanje proteina iz obeh hidrogelov. V prvem delu sta bili raztopini biopolimerov s pomočjo kalcijevih ionov zamreženi v obliki kroglic. Nanj je nato bil adsorbiran protein lizocim pri prisotnosti različnih koncentracij natrijevega klorida v adsorpcijskem mediju. Koncentracije proteina so bile določene s pomočjo merjenja absorbance pri 280 nm ob različnih časih. Iz dobljenih koncentracij so bile določene adsorpcijske kapacitete in konstante hitrosti adsorpcije z modelom psevdo-prvega reda. Nato sta bili pripravljeni novi raztopini biopolimerov, ki jima je bila dodana znana količina proteina. Raztopini sta tokrat bili zamreženi, ponovno s kalcijevimi ioni, v kapsulah, ki omogočajo sproščanje proteina iz hidrogela skozi svoje stranske površine. Sproščanje je potekalo v medijih z različnimi koncentracijami natrijevega klorida, količina sproščenega proteina pa je bila prav tako določena z merjenjem absorbance pri 280 nm. Iz rezultatov eksperimentalnega dela je razvidno znižanje adsorpcijske kapacitete biopolimerov in višanje konstante hitrosti psevdo-prvega reda ob višanju koncentracije soli v adsorpcijskem mediju. Iz rezultatov testov sproščanja je možno razbrati korelacijo med adsorpcijo proteina na hidrogel in sproščanjem proteina iz hidrogela.

• Language: Slovenian
• Keywords: alginat, nanoceluloza, hidrogel, adsorpcija, sproščanje proteinov
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2023
• PID: 20.500.12556/RUL-150652
• COBISS.SI-ID: 172564227
• Publication date in RUL: 21.09.2023

Secondary language

• Language: English
• Title: Influence of adsorption on protein release from alginate and nanocellulose hydrogels

Abstract

Biopolymers are a group of various proteins, nucleotides, fats, and polysaccharides that are produced in many organisms during metabolism. They are useful mainly because of their low cost, their renewability and, in particular, their biodegradability and biocompatibility. The latter two properties make them promising in the fields of medicine and pharmacy. Many biopolymers can be used to prepare hydrogels, i.e. cross-linked three-dimensional structures that are able to absorb water and swell without losing their structure. The use of hydrogels covers many fields and applications, among which the use in pharmaceuticals as carriers for (controlled) drug release stands out. In this master thesis, alginate and TEMPO-oxidised nanocellulose hydrogels were prepared in order to determine the influence of adsorption on protein release from both hydrogels. In the first part, the two biopolymer solutions were cross-linked in the form of beads by calcium ions. The protein lysozyme was then adsorbed on it in the presence of different concentrations of sodium chloride in the adsorption medium. The protein concentrations were determined by measuring the absorbance at 280 nm at various times. From the concentrations obtained, the adsorption capacities and adsorption rate constants were determined using a pseudo-first order model. Then, two new biopolymer solutions were prepared to which a known amount of protein was added. This time, the two solutions were cross-linked, again with calcium ions, in capsules which allow the protein to be released from the hydrogel through their side surfaces. The release was conducted in media with different concentrations of sodium chloride and the amount of protein released was also determined by measuring the absorbance at 280 nm. The experimental results show a decrease in the adsorption capacity of the biopolymers and an increase in the pseudo-first order rate constant with increasing salt concentration in the adsorption medium. From the results of the release tests, a correlation between the adsorption of the protein on the hydrogel and the release of the protein from the hydrogel can be seen.

• Keywords: alginate, nanocellulose, hydrogel, adsorption, protein release