A high-throughput label-free cell-based biosensor (CBB) system

Cell-based biosensors (CBBs) have important applications in biosecurity and rapid diagnostics. Current CBB technologies have challenges including cell immobilization on the sensors, high throughput fabrication and portability, and rapid detection of responses to environmental changes. We address these challenges by developing an integrated CBB platform that merges cell printing technology, a lensless charge-coupled device (CCD) imaging system, and custom-developed cell image processing software. Cell printing was used to immobilize cells within hydrogel droplets and pattern these droplets on a microfluidic chip. The CCD was used to detect the morphological response of the immobilized cells to external stimuli (e.g., environmental temperature change) using lensless shadow images. The morphological information can be also detected by sensing a small disturbance in cell alignment, i.e., minor alignment changes of smooth muscles cells on the biosensors. The automatic cell alignment quantification software was used to process the cell images (microscopic image was used as an example) and calculate the cell orientation in seconds. The same images were also manually processed as a control to validate and characterize the integrated platform functionality. The results showed software can measure the cell morphology (i.e., orientation) in an automated way without the need for labeling (e.g., florescent staining). Such an integrated CBB system will allow fabrication of CBBs at high throughput as well as rapidly monitor and measure morphological cellular responses.