Flame-Made Calcium Phosphate Nanoparticles for Biomolecule Delivery

Abstract

This thesis investigates the synthesis and characterization of flame-made calcium phosphate (CaP) nanoparticles for the targeted delivery of biomolecules, with a particular emphasis on nucleic acid vaccine applications. Utilizing flame spray pyrolysis, we achieved scalable and reproducible pro- duction of CaP nanoparticles. By tuning the flame ratio, we could control the unique properties of these nanoparticles. Their size distribution was characterized using Dynamic Light Scattering (DLS), while their transfection efficiency was evaluated through confocal microscopy and flow cytom- etry. Additional techniques such as Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), freeze-drying, and Fourier-Transform Infrared Spectroscopy (FTIR) were employed to assess the system’s stability, structure, and composition. These nanoparticles demonstrated a substantial capacity for loading double-stranded DNA (dsDNA), making them highly suitable for vaccine de- livery. To enhance their stability and transfection efficiency, the CaP nanoparticles were coated with poly-L-lysine (PLL), a cationic synthetic polymer. The PLL coating significantly reduced particle size and increased stability, addressing common challenges such as nanoparticle aggrega- tion and inefficient cellular uptake. The optimized DNA@CaP/PLL nanocarrier formulations were further examined for their DNA transfection efficiency. In vitro studies showed that PLL-coated CaP nanoparticles significantly improved the delivery and expression of DNA within target cells compared to uncoated nanoparticles. This enhanced performance is attributed to the increased sta- bility and improved cellular uptake facilitated by the PLL coating and the positive shift in surface charge of the formulations. The primary objectives of this research were to optimize the synthesis and coating parameters of CaP nanoparticles, maximize DNA loading, and enhance transfection efficiency. The findings suggest that PLL-coated CaP nanoparticles can serve as effective nanocarri- ers for biomolecule delivery applications, potentially improving immune responses through targeted delivery and sustained antigen release. This study contributes to the field of nanomedicine by presenting a robust method for producing and utilizing CaP nanoparticles in biomolecule delivery, particularly for vaccine development. The biocompatibility and biodegradability of CaP nanoparti- cles, combined with the enhanced functionality provided by PLL coating, offer a promising platform for advancing DNA vaccine efficacy. Future work will focus on in vivo validation and further optimization to fully realize the potential of these nanocarriers.