Aligned and suspended fiber force probes for drug testing at single cell resolution.

The role of physical forces in disease onset and progression is widely accepted and this knowledge presents an alternative route to investigating disease models. Recently, numerous force measurement techniques have been developed to probe single and multi-cell behavior. While these methods have yielded fundamental insights, they are yet unable to capture the fibrous extra-cellular matrix biophysical interactions, involving parameters of curvature, structural stiffness (N m(-1)), alignment and hierarchy, which have been shown to play key roles in disease and developmental biology. Using a highly aggressive glioma model (DBTRG-05MG), we present a platform technology to quantify single cell force modulation (both inside-out and outside-in) with and without the presence of a cytoskeleton altering drug (cytochalasin D) using suspended and aligned fiber networks (nanonets) beginning to represent the aligned glioma environment. The nanonets fused in crisscross patterns were manufactured using the non-electrospinning spinneret based tunable engineering parameters technique. We demonstrate the ability to measure contractile single cell forces exerted by glioma cells attached to and migrating along the fiber axis (inside-out). This is followed by a study of force response of glioma cells attached to two parallel fibers using a probe deflecting the leading fiber (outside-in). The forces are calculated using beam deflection within the elastic limit. Our data shows that cytochalasin D compromises the spreading area of single glioma cells, eventually decreasing their 'inside-out' contractile forces, and 'outside-in' force response to external strain. Most notably, for the first time, we demonstrate the feasibility of using physiologically relevant aligned fiber networks as ultra-sensitive force (∼nanoNewtons) probes for investigating drug response and efficacy in disease models at the single cell resolution.