Fig. 3: Scatter plots of the trapped nanoparticles.

Scatter plots of negatively charged single 80 nm diameter gold nanoparticles confined in a contact-free manner in 200 nm (blue) and 500 nm (green) diameter pockets inside a native device (left) and the polyethyleneimine and poly(sodium 4-styrenesulfonate)-functionalized (right) PDMS device. The spread of the scatter plots of the trapped particles in the 500 nm and 200 nm pockets shows lower trapping strength of the potential trap for 500 nm nanopockets than for 200 nm pockets. The calculated stiffness constants (k) for the functionalized and native device were comparable for both the 200 nm and 500 nm nanopockets, denoting the homogeneous surface functionalization of the device