Realization of porous SiO2 nanoparticles for analyte sensing in the brain

Open Access
- Author:
- Ascani Orsini, Alessandro
- Area of Honors:
- Engineering Science
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Bruce Gluckman, Thesis Supervisor
Bruce Gluckman, Thesis Honors Advisor
Mark William Horn, Faculty Reader
James Hansell Adair, Thesis Supervisor - Keywords:
- nanotechnology
optical probes
fluorescence
spreading depression
epilepsy
silica
nanoparticles - Abstract:
- Many diseases affecting the brain have an underlying molecular base that is difficult to study due to the lack of instrumentation with high spatial and temporal resolution. To address this issue we present a study on the fabrication of fluorescent porous silica nanoparticles. These particles aim to restrict the analysis of the system only to the Extracellular Matrix (ECM), reduce the photobleaching rate of the fluorophores, mak- ing them last longer and allow the colocalization of multiple dyes permitting in this way to monitor multiple analytes. Starting from the Stöber procedure we used Tetram- ethylorthosilicate (TMOS) to accelerate the aggregation reaction obtaining highly mi- croporous particles. Based on this revised synthesis we characterized the particles with encapsulated fluorescein, which resulted in leakage of the dye due to its size being very close to the particles’ pore diameter. Using a second synthesis to build a shell around the fluorescent particles, we identified the ideal concentration of orthosilicate to use to prevent the leakage and obtain maximum absorbance and emission from the fluo- rophores. In this way, we developed a probe that can be applied for analyte sensing in the brain. Further testing will be needed to assess the effect of the encapsulation on photobleaching rate and Förster Resonance Energy Transfer (FRET) excitation as well as the integration of the nanoparticles with an external system.