This thesis presents the development of elastomeric microfabricated cell sorting devices using soft lithography, aiming to replace conventional fluorescence-activated cell sorters (FACS) with more cost-effective, disposable alternatives. The devices utilize microfluidic control for cell sorting, offering advantages such as higher sensitivity, reduced cross-contamination, and the ability to sort single cells. The first generation of the device uses electrokinetic flow for sorting, while the second generation integrates microvalves and micropumps for improved flow control and cell manipulation. The devices have been applied in high-throughput screening of green fluorescent protein (GFP) variants, digital genetic circuits, and the analysis of magnetotactic bacteria using a SQUID microscope. The microfabricated cell sorters are also capable of performing sensitive optical detection of bacterial cells and DNA, and can be used as standalone devices or integrated into diagnostic systems. The research highlights the potential of microfluidic technologies in advancing biomedical research, enabling more efficient and cost-effective cell sorting and analysis. The thesis also discusses the integration of these devices with other technologies, such as superconducting quantum interference devices (SQUIDs), to expand their applications in biomagnetism and cellular computation. The work demonstrates the feasibility of using microfabricated cell sorters for a wide range of biological applications, including directed evolution, genetic circuit analysis, and the study of magnetic properties of bacteria. The devices are designed to be disposable, reducing the risk of cross-contamination and improving the efficiency of cell sorting processes. The research contributes to the development of more robust and versatile cell sorting technologies for use in various biological and medical fields.This thesis presents the development of elastomeric microfabricated cell sorting devices using soft lithography, aiming to replace conventional fluorescence-activated cell sorters (FACS) with more cost-effective, disposable alternatives. The devices utilize microfluidic control for cell sorting, offering advantages such as higher sensitivity, reduced cross-contamination, and the ability to sort single cells. The first generation of the device uses electrokinetic flow for sorting, while the second generation integrates microvalves and micropumps for improved flow control and cell manipulation. The devices have been applied in high-throughput screening of green fluorescent protein (GFP) variants, digital genetic circuits, and the analysis of magnetotactic bacteria using a SQUID microscope. The microfabricated cell sorters are also capable of performing sensitive optical detection of bacterial cells and DNA, and can be used as standalone devices or integrated into diagnostic systems. The research highlights the potential of microfluidic technologies in advancing biomedical research, enabling more efficient and cost-effective cell sorting and analysis. The thesis also discusses the integration of these devices with other technologies, such as superconducting quantum interference devices (SQUIDs), to expand their applications in biomagnetism and cellular computation. The work demonstrates the feasibility of using microfabricated cell sorters for a wide range of biological applications, including directed evolution, genetic circuit analysis, and the study of magnetic properties of bacteria. The devices are designed to be disposable, reducing the risk of cross-contamination and improving the efficiency of cell sorting processes. The research contributes to the development of more robust and versatile cell sorting technologies for use in various biological and medical fields.