Correlating Super-Resolution Microscopy with Transmission Electron Microscopy to characterize nanoparticles

Identifier:  TFG:2966

Handle: https://hdl.handle.net/20.500.11797/TFG2966

Authors:  Izquierdo Lozano, Cristina

Abstract:
Nanoparticles (NP) used for the delivery of therapeutics have significant advantages over conventional chemotherapeutics as they can encapsulate both hydrophilic and hydrophobic molecules and provide physical protection to the encapsulated drug. Additionally, they present enhanced delivery of the drugs and tumour specific accumulation thanks to the enhanced permeation and retention (EPR) effect. However, the lack of standardization in the characterization of the NP is a major impediment for their approval for clinical applications. For this reason, three different techniques have been used in this study for the characterisation of poly(lactic-co-glycolic acid)-polyethylene glycol (PLGA-PEG NP), in order to standardize experimental protocols for the development of novel nanomedicine-based therapeutics. These techniques consist of Dynamic Light Scattering (DLS), Stochastic Optical Reconstruction Microscopy (STORM) and Transmission Electron Microscopy (TEM). More specifically, the two main objectives were a) to analyse and compare the size uniformity of NP formulated either manually or using a microfluidic device, and b) to quantify the encapsulation efficiency of these methods by using STORM. DLS showed a 75% increase in the average size of the NPs when compared to STORM and TEM. The width in the half of the height for the different formulations was 20 nm in the case of the formulations with the microfluidic device and of 35 nm for the manual formulations. Thus, NPs were more homogeneous and better controlled when formulated using a microfluidic device, in terms of size and size distribution. Furthermore, STORM has been proven a useful method for NP characterisation and, more importantly, it has proven to be a promising and more precise method to quantify the encapsulation efficiency at a single particle level.