We use droplets for the same reason the biologists and chemists use test tubes, that is, to conduct reactions. The only 'little' difference is that the droplets, serving as compartmentalized microreactors, allow us to conduct millions of such reactions in parallel! This compartmentalization further ensures minimal sample cross-contamination, and the small size (~100 pL) also enhances reaction efficiency by facilitating rapid mixing and thermal transfer. Small size also creates a controlled environment to encapsulate and study single-cells in isolation, providing a closer look into individual cell behaviors within a heterogeneous population.  Not just single cells, these droplets can also be used to host tissue slices and subject them to various test conditions. This allows to test a tumor sample from a cancer patient against a range of different drugs to find the most effective personalized medication.

Moreover, droplets can be manipulated with precision in microfluidic channels, enabling automated sorting, merging, and splitting, which are crucial for complex bioanalytical assays. The droplet format is particularly compatible with sensitive detection techniques like fluorescence-based assays, as it provides a confined space that concentrates the signal and reduces background noise. Collectively, these properties make droplets in microfluidics a powerful tool for bioanalytical applications, including diagnostics, drug discovery, and fundamental biological research.

Integrated Microfluidic Systems or IMS is the amalgamation of fluidic, optic, electronic, signal processing and computational modules that collectively delivers a precise control over the operations conducted within a microfluidic chip. For e.g. to selectively isolate a droplet showing the activity of your interest (may be containing the rare cell producing antibody against a virus!)

We need to generate these droplets at high frequencies using precise fluid flow control. We also have to detect the droplets and then analyze them to make a decision on the manipulation operation within a few microseconds! This detection can be fluorometric, requiring monochromatic light sources, typically lasers, to excite the droplets followed by highly sensitive photosensors to collect the fluorescence from the droplets. Another method is electrical detection, requiring real-time dielectric analysis methods such as microfluidic impedance analysis. These signals need further processing via high-speed electronic systems particularly via Field Programable Gate Array (FPGA) programming.  In addition, it is also great to have these operations work in an automated way as manual estimations of multiple control variables is mostly erroneous. 

Overall,  IMS enables high-throughput microfluidic operations with high-precision to conduct complex bioanalysis at single cell level. 

IMS has become a cornerstone in advancing several critical areas of biomedical research, including cancer research, antibody screening, drug discovery, therapeutics, single cell-omics etc. These fields benefit immensely from the precision, scalability, and efficiency that IMS technology offers. For example., in cancer research, it offers a unique platform for understanding tumor heterogeneity and the mechanisms behind cancer progression and metastasis. By analyzing circulating tumor cells (CTCs) or even tumor micro-slices, we can uncover vital information about cancer's drug response, genetic diversity or resistance mechanisms. This paves the way for therapies tailored to the patient specific tumor profile. Further, its ability to conduct thousands of parallel assays also allows for the rapid screening and identification of high-affinity antibodies. 

The high-throughput capability of IMS is invaluable in the fast-paced development of new therapeutics and vaccines, where identifying candidates that can target specific antigens is paramount. This technology also enables precise control over the microenvironment of the biochemical reactions, allowing for more accurate analysis and thus predictions of a drug's efficacy and toxicity in physiological conditions facilitating the advances in field of drug discovery.