The goal of this project is to develop an inexpensive, easy-to-use Antibiotic Susceptibility Testing (AST) platform for rapid antimicrobial susceptibility profiling of pathogens. This project will utilize Escherichia coli K12 as a model organism. Here we propose a device that incorporates the working principle of light microscopy or a speckle-scanning pictographic lensless imaging scheme to visualize (in real-time) the growth of bacterial cells in a microscopic population throughout an antibiotic concentration gradient. This system will utilize a microfluidic platform that consists of three independent wells connected via a porous membrane to establish the gradient over the middle agar growth well. The device may further be optimized by directly imaging a blood sample, effectively bypassing the time it takes to perform traditional culture isolation and propagation for antibiotic susceptibility testing. The time of AST will be decreased to a 1-2 hour process, with observations of growth taken frequently within this timeframe. A zone of inhibition will be determined using the relative growth of individual cells along the span of the antibiotic gradient. The minimum inhibitory concentration may then be calculated using a linear diffusion approximation. These results will help to conclude what antibiotic is the appropriate treatment for a patient to combat antibiotic resistance.