Micron-Scale Biological Devices


The advent of micro-fluidics has been a boon to research in biology and medicine. Already many such devices exist in the commercial domain reducing what were a plethora of flasks, transfer processes and reactions at the macroscopic scale (even with a few micro-liters) to something that works in nano- and femto liter volumes.
We are using the relatively simpler process of soft-lithography by optimizing patterns using phot

The bacterial mother machine devlice (with high autofluorescence) and the assembly of the entire device (Manasi Gangan)

oresist that can be exposed to UV and post-baking used for building channels, flows and growth-chambers for cells.
We have reproduced the ‘mother-machine’ for bacterial cells described first by Wang et al. from Suckjoon Jun’s lab.

We are currently testing the results and developing some image analysis tools to extract meaningful numbers from the device.

For more on Biological Microfluidics, see the review by Velve-Casquillas et al. (& Phong Tran) 2010 Nano Today.

Bacterial cell division

Populations of E. coli in microscopy

HupA (red) expressing E. coli with DIC (green) overlaid in confocal microscopy

The heat-stable protein HU was isolated first by Josette Rouviere-Yaniv and Gros in 1975 in a study where they systematically screened using an DNA-binding affinity-purification method for heat-stable proteins from E. coli cell extracts (1). This protein has been implicated in DNA replication initiation and cell cycle control (2,3). More recently the nucleoid binding HU protein from Mycobacterium tuberculosis
has been crystallized and the structure used to develop a small molecule which binds to HU and inhibits Mtb growth (4). This would appear to suggest surprisingly large number of physiologically critical bacterial proteins are still to be characterized that could help in the newly coined “post antibiotic era”.


  1. J Rouvière-Yaniv and F Gros (1975) Characterization of a novel, low-molecular-weight DNA-binding protein from Escherichia coli. Proc Natl Acad Sci U S A. 1975 Sep; 72(9): 3428–3432.
  2. Jaffe A, Vinella D, D’Ari R. (1997) The Escherichia coli histone-like protein HU affects DNA initiation, chromosome partitioning via MukB, and cell division via MinCDE. J Bacteriol. 179(11):3494-9.
  3. Jason Kahn’s Lab (U. Maryland, USA) on Prokaryotic DNA Replication
  4. Bhowmick,T., Ghosh, S., Ramagopal,U.A.,Dey, D. Ramakumar,S. and Nagaraja,V. (2014) Targeting Mycobacterium tuberculosis nucleoid associated protein HU by structure based inhibitors. Nature Communications. 5:4124
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