Synthesis and functionalization of magnetic iron oxide nanocrystals
Author
Jakobsson, Jakob
Term
4. term
Education
Publication year
2019
Submitted on
2019-06-10
Pages
60
Abstract
This thesis examines the synthesis and functionalization of magnetic iron oxide nanocrystals to enhance stability and enable imaging. Particles were prepared using two routes, co-precipitation and thermal decomposition, and characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). DLS indicated hydrodynamic sizes of approximately 15–40 nm depending on synthesis, whereas TEM revealed smaller individual cores, suggesting that the nanoparticles form clusters in dispersion. The cores were nearly monocrystalline and displayed magnetic properties consistent with published reports. Silica coating improved colloidal stability, although the shell thickness proved difficult to control; TEM confirmed successful core encapsulation. Rhodamine B was conjugated to APTES via EDC/NHS coupling chemistry, and attempts to condense the linker on the silica surface led to substantial APTES aggregates in nanoparticle dispersions. Overall, the work demonstrates practical synthesis routes, stabilization through silica coating, and a pathway to fluorescent labeling, while highlighting challenges with shell control, clustering, and surface functionalization.
Denne afhandling undersøger syntese og funktionalisering af magnetiske jernoxid-nanokrystaller med henblik på øget stabilitet og billeddannelse. Partiklerne blev fremstillet ved to tilgange, samutfældning og termisk nedbrydning, og karakteriseret med dynamisk lysspredning (DLS) og transmissions-elektronmikroskopi (TEM). DLS målte hydrodynamiske diametre på ca. 15-40 nm afhængigt af syntesemetode, mens TEM viste mindre individuelle kerner, hvilket indikerer, at partiklerne forekommer som klynger i dispersion. Kernerne var næsten monokrystallinske og udviste magnetiske egenskaber i overensstemmelse med litteraturen. En silikaskal forbedrede kolloidal stabilitet, men var svær at kontrollere i tykkelse; TEM bekræftede dog indkapslingen af kernerne. Rhodamin B blev koblet til APTES via EDC/NHS-kemi, og der blev forsøgt kondensering af APTES på silikaoverfladen, men dette gav anledning til markante APTES-aggregater i partikel-dispersionen. Samlet demonstrerer arbejdet gennemførlige synteseveje, stabilisering via silikacoating og en strategi for fluorescerende mærkning, samtidig med at udfordringer med skalkontrol, klyngedannelse og overfladefunktionalisering identificeres.
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