Strukturna karakterizacija stroncijem dopiranih kalcijevih fosfata Rietveldovom metodom utočnjavanja

master's thesis

• Title (english): Structural characterization of strontium substituted calcium phosphates by Rietveld refainment method
• Author: Ana Gudelj
• Mentor: Hrvoje Ivanković (mentor)
• Committee member: Hrvoje Ivanković (predsjednik povjerenstva)
• Committee member: Marica Ivanković (član povjerenstva)
• Committee member: Domagoj Vrsaljko (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2020-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Znanstvena istraživanja u sklopu inženjerstva koštanog tkiva usmjerena su ka istraživanju materijala za koštane usadke koji oponašaju prirodno koštano tkivo. Kako bi materijal bio odgovarajući mora zadovoljavati tražena svojstva, od mehaničkih do bioloških, kemijskih i fizikalnih. Kao visokopotencijalni materijal pokazao se hidroksiapatit, koji zadovoljava uvjete poput biokompatibilnosti, bioaktivnosti, osteoinduktivnosti, biorazgradnje i sl., te je strukturno i kemijski sličan biološkom apatitu koji se nalazi u prirodnom koštanom tkivu. Cilj ovog istraživanja je strukturna karakterizacija sintetizitanog hidroksiapatita iz biogenog izvora supstituiranog stroncijem (0, 1, 5 and 10 mol%), koji ima važnu ulogu u razvoju koštanog tkiva i koristi se za tretiranje bolesti koštanog sustava. Sinteza iz biogenog izvora omogućuje da produkt bude nestehiometrijski hidroksiapatit, koji pokazuje više sličnosti biološkom apatitu. Osim toga, sadrži brojne ione važne za razvoj koštanog tkiva. Dobiveni uzorci prije i nakon toplinske obrade analizirani su rendgenskom difrakcijskom analizom (XRD) i Rietveldovom metodom utočnjavanja pomoću računalnog programa DIFFRAC.SUITE TOPAS V.5.0. Pripremljeni kalcijevi fosfati (CaP) sastoje se od hidroksiapatita (HAp), oktakalcijevog fosfata pentahidrata (OCP) i amorfnog kalcijevog fosfata (ACP), a toplinski obrađeni uzorci od β-trikalcijevog fosfata (β-TCP) i ACP-a. Povećanjem udjela stroncija dolazi do povećanja parametara jedinične ćelije dobivenih CaP zbog supstitucije ionom većeg ionskog radijusa. Stroncij u HAp-u zauzima Ca1 položaj, u OCP-u Ca3, Ca4, Ca7 i Ca8, dok u β-TCP-u Ca1, Ca2, Ca3 i Ca4 položaje.

Abstract (english)

The main goal of scientific researches in the field of bone tissue engineering is to synthetize a material that mimics natural bony tissue, in order to use it as a bone implant. The material has to be chemically and structurally similar to bony tissue, and possess required properties, such as biocompatibility, bioactivity, osteoinductivity, biodegradibility and mechanical support. Hydroxyapatite (HAp) has shown all of the above mentioned properties and is very similar to biological apatite, that is present in natural bony tissue. Therefore, the aim of this research is a structural characterization of synthetized HAp obtained from biogenic source, along with strontium substitution (0, 1, 5 and 10 mol%), that is crucial for bone growth and is used for treating osteoporosis and similar diseases. Result of using biogenic source is multi-substituted nonstochiometric HAp, which is more similar to biological apatite than synthetic HAp. Various trace elements present in HAp obtained from biogenic source are crucial for bone growth. Prepared samples were analysed by X-ray diffraction analysis (XRD), in order to determine their phase composition. Obtained results were additionally processed by Rietveld refinement method using software, DIFFRAC.SUITE TOPAS V.5.0. To determine thermal stability of samples, they were heat-treated at 1200 °C and analysed by X-ray diffraction and using Rietveld refinement method. Prepared calcium phosphates were composed of hydroxyapatite (HAp), octacalcium phosphate pentahydrate (OCP) and amorphous calcium phosphate (ACP), while heat-treated samples were composed of β-tricalcium phosophate (β-TCP) and amorphous calcium phosphate (ACP). Along with increase of Sr-substitution level, lattice parameters of obtained CaPs increased, as a result of larger radius of substitued strontium ion. Strontium ion occupies in hydroxyapatite Ca1 site, in OCP sites Ca3, Ca4, Ca7 and Ca8, while in β-TCP it occupies sites Ca1, Ca2, Ca3 and Ca4.

• Keywords: biogeni izvor; dopiranje; hidroksiapatit; Rietveldova metoda utočnjavanja; stroncij
• Keywords (english): biogenic source; substitution; hydroxyapatite; Rietveld analysis; strontium
• Language: croatian
• URN:NBN: urn:nbn:hr:149:827989
• Project: Number: IP-2014-09-3752; Title: Razvoj biokompatibilnih materijala na temelju hidroksiapatita za primjene u inženjerstvu koštanog tkiva; Title: Development of Biocompatible Hydroxyapatite Based Materials for Bone Tissue Engineering Applications; Acronym: HaTEA; Leader: Hrvoje Ivanković; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-03-02 15:14:45