Controlled patterning of colloidal particles into advanced hierarchical structures is of global interest for many applications such as photonics, sensing, bioelectronics and drug delivery. Electric field-assisted assembly in particular offers a facile way to exploit nanoscale functionalities in macroscopic constructs. In my talk, I will discuss the basics of electric field-induced polarization, parameters involved in AC electrokinetic driven flows and their role in fabrication of a rich variety of colloidal architectures. In particular, I will showcase my group’s approach using alternating current dielectrophoresis (AC- DEP) and AC electrohydrodynamics (AC-EHD) for fabricating one-dimensional (1D) microwires and 2D films from metallic, dielectric and semiconducting nanoparticles, and cellular microarrays of live cells with magnetic-responsiveness and tunable densities at a single cell level on a chip. Further integration of the electrode chips with impedance spectroscopy combined with the novel use of zwitterionic buffers has allowed us to perform rapid, real-time viability testing and antibiotic susceptibility profiling of bacterial cells under an hour and to probe the AC conductivity of ultradilute colloidal suspensions as low as 0.002 % (w/v).
Shalini Gupta is an Associate Professor of Chemical Engineering at the Indian Institute of T echnology Delhi. She heads the Nanoengineered Materials and Biosensing lab that specializes in developing novel biosystems for rapid and affordable point-of-care medical diagnosis, targeted drug delivery and therapy, and nanoscale engineering approaches for colloidal manipulation and interactions in external fields. The overarching goal of Dr. Gupta’s interdisciplinary laboratory is to harness the basic knowledge and tools offered by cellular and molecular biology, microfabrication technology, materials chemistry and interfacial science in order to develop techniques for ultrasensitive detection of disease biomarkers and synthesis of novel biomaterials and colloidal architectures on a chip. Over the last 9 years, her group has made seminal contributions in developing simple and affordable, yet sensitive and scalable technologies including SeptifloTM for the rapid diagnosis and targeted therapy of bacteria-related complications. The lab is particularly focused on the use of these technologies for better infectious disease management in order to reduce the emerging threat of antimicrobial resistance. Dr. Gupta has published 33 papers, filed 4 Indian and 3 international patents, and founded a startup, NanoDx Healthcare Pvt. Ltd. (https://www.nanodxhealthcare.com).
This seminar is compulsory for students registered for course CL 702 or CL 704.