In situ synthesis of gold nanorods on SiO₂-substrates
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Nanotechnology (MPNAT), MSc
Publicerad
2023
Författare
Wilson, Sean
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The implantation of a medical device introduces a high risk of infection and bacterial
biofilm formation on the device surface. These biomaterials-associated infections
(BAI) are difficult to treat using conventional methods, such as high dosages
of antibiotic treatments, as the bacteria are protected by the biofilm. A promising
treatment is to modify the implant surfaces with gold nanorods, which can photothermally
eradicate bacteria beneath the biofilm with heat generated from localized
surface plasmon resonance (LSPR). As such there is a need to develop methods that
reliably produce gold nanorods of a size that produces LSPR at wavelengths within
the biological window and that stably bind the particles to the material surface homogeneously.
In this thesis, a method has been developed to grow gold nanorods in situ on
SiO2-glass and silicon wafers by binding gold nanoparticle seeds to surfaces using
(3-Mercaptopropyl)- trimethoxysilane (MPTMS) as a linking molecule. The seeds
were then grown into rods using a modified growth solution. The method has also
been adapted to surface sensitive analysis to demonstrate the increased possibility
to study anisotropic nanoparticles this method brings. In situ quartz crystal microbalance
(QCM-D) analysis was used to study the formation of the self-assembled
monolayer of MPTMS, the chemisorption of gold nanoparticle seeds, and how the
growth rates of the particles vary over time, possibly due to both their increasing
size as well as variations in solution concentrations.
The developed method produced nanorods with a demonstrated rod yield of ~69%
directly on SiO2-glass surfaces. The rods had an aspect ratio (AR) that could
be customised to tune the wavelength of LSPR. The ability to tune the optical
properties of the rods could allow this method to be used to grow gold nanorods for
other applications, such as sensing, as well. Here the tuning was used to demonstrate
the effect of silver ions within the growth solution and to produce nanorods with
LSPR at the near infrared (NIR) wavelength of ~800nm in the biological window.
Beskrivning
Ämne/nyckelord
gold nanorods , localised surface plasmon resonance , NIR , biofilm , implants , photo-thermal eradication , infection , MPTMS , in-situ growth , QCM-D , insitu analysis