Synthesis of silica hollow nanomaterials for biomedical applications [thesis]

Lip Son Chin
2014
Silica hollow spherical nanomaterials have been widely studied in various biomedical-related applications due to their inertness and strong mechanical properties. They provide excellent protection against biological degradation of the encapsulated materials. The development of an advanced silica nanomaterial for biomedical imaging and therapeutic applications is therefore presented in this thesis. The work begins with the fabrication of silica hollow spheres via a self-templating route
more » ... a two-step synthesis process. Following the successful development of a robust synthetic method, the particles were evaluated for their applicability in ultrasound imaging. The robust synthesis method developed allowed tuning of the silica hollow spheres' structure, morphology and pore size simply by manipulating the temperature and aging duration. In-depth studies of the pore size evolution via Brunauer–Emmett–Teller (BET) analysis revealed that the pore diameter increased initially but narrowed with aging time due to the rearrangement of silica network. Owing to the presence of the hollow cavities and mesopores, the silica hollow spheres exhibited stronger ultrasound contrast compared to the pristine silica solid spheres, showing their superiority as ultrasound contrast agents. In the second part of this thesis, the role of the silica hollow spheres in bio-imaging was extended further into creating a dual-modal contrast agent (ultrasound and magnetic resonance imaging) by incorporating perfluorodecalin (PFD) into the particles. High PFD loading was achieved by encapsulating the PFD in silica nanocapsules via a one-pot synthesis method. In this work, Pluronic F68 (PF68) was used to stabilise the PFD nanoemulsion. The size of the PFD nanoemulsions, which dictates the size of the silica nanocapsules, could be varied easily by changing the concentrations of PF68. Successful incorporation of PFD (78% wt) into the silica nanocapsules' core and high mechanical stability of the structure allowed the use of the particles as ultr [...]
doi:10.26190/unsworks/18169 fatcat:oj7zceyenrcphkeytwvnmcgxcu