From particle to platelet: optimization of a stable, high brightness fluorescent nanoparticle based cell detection platform.

Nanoparticles are increasingly used as diagnostic tools due to the ease with which their surface chemistry, optical and physical properties can be controlled. Molecules, drugs, enzymes and fluorophores can be protected within the particle core or conjugated externally conferring nanoparticle biocompatibility, target specificity or environmental sensitivity. This study details the development and characterisation of stable, bright, dye-doped silica nanoparticles which are surface functionalised with PAMAM dendrimers to enable efficient conjugation to platelet activation-specific antibodies. We present the physical and optical properties and demonstrate colloidal stability. We also provide the first evidence of how NPs can be employed to specifically label human platelets immobilised on a lab-on-a-chip platform. Using a single step protocol, we demonstrate highly specific platelet labelling with the distribution of antibody-conjugated NPs matching that expected for the platelet GPIIb/IIIa receptor. The work highlights the potential of functionalized fluorescent NPs as diagnostic tools for cardiovascular disease. FROM THE CLINICAL EDITOR: This study details the development and characterization of PAMAM dendrimer functionalized, stable, and bright dye-doped silica nanoparticles that enable efficient conjugation to platelet activation-specific antibodies. These fluorescent NPs may specifically label human platelets that can be used as diagnostic tools for cardiovascular disease.