Research Areas

One of the ways of harnessing the force of interface (i.e. surface tension) for microfluidic devices is through application of electric fields. Drop shape and position is easily manipulated through spacial and temporal control of the applied electric field. This is the basis for the well known droplet based microfluidic platform commonly referred to as EWOD (electrowetting on dielectric). Our group studies linear and non-linear dynamics of electrically actuated interfaces. We also investigate the interesting behavior that emerges when such non-linear systems interact with each other. Our group has observed and explained several interesting phenomena pertaining to interface dynamics in microfluidics. In addition to aiding development of next generation open-chip EWOD platform for integration with microsurgical tools, our work also envisages development of interface based micro-robots (BubbleBot).

Characterising heterogeneity in cell populations is of significant scientific interest for developing better in-depth understanding of biological systems. Such heterogeneity studies, requiring single cell level measurements, are best enabled by microfluidic devices. Our group develops systems to perform multi-modal measurements at single cell level. Conventional cytometers have been differentiating cells based on their biochemical properties through fluorescence measurements. However, they do not provide information about other measurable properties of cells. For example, mechanical properties of cells (& cell clusters) are known to be affected by diseases or changes in their environment. In order to achieve various goals, cells are also known to modulate their mechanical properties. We have developed several new microfluidic techniques to study mechanical properties of cells. We have demonstrated multimodal capabilities by integrating techniques to probe electrical signatures and fluorescent signals from individual cells. In addition to developing measurement platforms we are also developing techniques to isolate and study circulating tumour cells & tumour cell clusters.

Antimicrobial-resistant infections currently claim 700,000 lives each year from all across the world and this figure will increase alarmingly to 10 million by 2050 if it is not stopped. One of the methods to tackle biofilms involves prevention of biofilm formation by actively killing the bacteria as soon as they arrive on the surface. Use of antibiotic (chemically) coated surfaces has a significant concern, as widespread antibiotic usage has been linked to the emergence of several multi-drug resistant strains of infectious diseases, some of which (e.g. Tuberculosis) may become epidemic. Consequently, instead of killing bacteria chemically, our group explores alternative physical methods for contact killing of bacteria. Here, nano-structured surfaces are used to kill bacteria landing on the surface. We look at development of low-cost mechanically robust surfaces for practical applications. Our group also investigates techniques to coat active material on the nano-structures to enhance killing efficiency. We are also interested in experimental studies focusing on understanding the fundamentals of the contact killing mechanism.

Controlled generation of micro-droplets is of significant interest for a large variety of applications in pharmaceutical industry, additive manufacturing, electronic manufacturing, etc. Today droplet jetting based systems are being used for defining conductive and dielectric patterns for the electronic industry on non-standard and curved surfaces. In pharmaceutical industry precise dosage can be delivered using microdroplet jetting techniques. Single cell trapping and their multi-omic analysis is being enabled by microdroplet generation technologies. Droplet jetting based 3D printing is useful not only in conventional manufacturing but also bioprinting of cells for fabrication of artificial tissues and organs. Using a high-speed camera, we have been experimentally investigating interaction of droplets with superhydrophobic meshes. Depending on the impact velocity, several interesting phenomena are observed. Based upon the insight gained from the fundamental studies we have developed a technique to jet microdroplets with precise control. We have also developed a technology to print a large array of droplets using patterned superhydrophobic surfaces.

The development of flexible devices that have applications in healthcare, has recently gained much interest because of their cost-effectiveness, portability, and user‐friendliness with distinct advantages of safe disposal and biosafety management. These devices can be interfaced with curved surfaces, complex geometries, and soft and non‐planar body surfaces. We are working on the fundamentals and applied an aspect of sensors that are based on various sensing mechanism (electrochemical, mechanical, optical).

The skin conformal sensor can perform non-invasive and continuous monitoring of vital health parameters. We are working on a different aspect of the sensor to retract information from the human body using its largest organ, the skin.

Recently, the paper has drawn significant interest among the research community because it is ubiquitous, cheap, and environmentally friendly. The nanomaterials-modified paper represents a new concept that utilizes paper as functional parts in various devices. We are modifying/controlling the paper properties by using novel nanomaterials for various biomedical applications.