Utjecaj amino kiselina na taloženje kalcijevih fosfata

master's thesis

• Title (english): Influence of amino acids on precipitation of calcium phosphates
• Author: Jasmina Validžić
• Mentor: Jelena Macan (mentor)
• Committee member: Jelena Macan (predsjednik povjerenstva)
• Committee member: Marica Ivanković (član povjerenstva)
• Committee member: Maja Dutour Sikirić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2016-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry; Physical Chemistry

Abstract

Interakcije malih organskih molekula ili makromolekula s anorganskim kristalima važne su za razumijevanje procesa taloženja u prirodi i pripravi novih materijala. Između različitih biominerala, kalcijevi fosfati (CaP) privlače posebnu pažnju zbog njihove uloge u biološkoj i patološkoj mineralizaciji te industrijskim procesima. U novije vrijeme istraživanja utjecaja aditiva na nastajanje CaP su uglavnom usmjerena na protein i njihove sintetske analoge. Iako su opći principi tih interakcija poznati, uloga pojedinih aminokiselina u njima još uvijek nije razjašnjena. Glavni cilj ovog istraživanja bio je istražiti utjecaj strukturno različitih aminokiselina, asparaginske kiseline (Asp), lizina (Lys) i tirozina (Tyr) na nastajanje i transformaciju CaP. Pri pH 7,4, bočni lanac asparaginske kiseline je negativno, a lizina pozitivno nabijen, dok je bočni lanac tirozina hidrofoban. Napredovanje reakcije praćeno je potenciometrijski, što je omogućilo određivanje vremena indukcije. Nastali talog analiziran je pomoću FTIR spektroskopije i pretražne elektronske mikroskopije (SEM). Dobiveni rezultati pokazali su da pri danim eksperimentalnim uvjetima asparaginska kiselina utječe na vrijeme indukcije i mehanizam transformacije kalcijevih fosfata. Lizin također utječe na vrijeme indukcije te na morfologiju nastalih kristala kalcij deficijentnog apatita, a tirozin ne utječe na vrijeme indukcije, ali utječe na morfologiju taloga.

Abstract (english)

Knowledge about the mechanisms of interactions of soluble small organic molecules or macromolecules with inorganic crystals is of major importance in understanding the crystallization processes in nature, as well as for the production of materials. Among different biogenic crystals, calcium phosphates (CaPs) attract attention due to their role in the normal and pathological mineralization, as well as in industrial processes. Recent investigations of influence of additives on CaP formation described in literature are mostly focused on proteins and their synthetic analogues. Although general principles of these interactions are known, the role of specific amino acids is still not clear. The aim of this research was to investigate the influence of structurally different amino acids on CaP formation and transformation. The selected amino acids, aspartic acid (Asp), lysine (Lys) and tyrosine (Tyr) at pH 7.4,have either charged (Asp, Lys) or hydrophobic side chain (Tyr). The progress of reaction was continuously followed potentiometrically, which enabled determination of induction time. Fourier transform infrared spectroscopy (FTIR) and scannig electron microscopy (SEM) were used for characterization of the precipitates. The obtained results show that, in the given experimental conditions, investigated aminoacids exhibited different effects. Aspartic acid influenced induction time and the mechanism of transformation of calcium phosphates. Lysine had an influence on the induction time and morphology of formed calcium deficient apatite crystals. Tyrosine showed no influence on the induction time, but it influenced the morphology of the precipitate.

• Keywords: aminokiseline; kalcijevi fosfati; transformacija
• Keywords (english): amino acids; calcium phosphates; transformation
• Language: croatian
• URN:NBN: urn:nbn:hr:149:819742
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2017-11-09 13:07:06