Biomedical Microdevices

, Volume 16, Issue 5, pp 717-725

First online:

Directed transport of bacteria-based drug delivery vehicles: bacterial chemotaxis dominates particle shape

  • Ali SahariAffiliated withSchool of Biomedical Engineering and Sciences, Virginia Tech–Wake Forest University
  • , Mahama A. TraoreAffiliated withDepartment of Mechanical Engineering, Virginia Tech
  • , Birgit E. ScharfAffiliated withDepartment of Biological Sciences, Virginia Tech
  • , Bahareh BehkamAffiliated withSchool of Biomedical Engineering and Sciences, Virginia Tech–Wake Forest UniversityDepartment of Mechanical Engineering, Virginia Tech Email author 

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Several attenuated and non-pathogenic bacterial species have been demonstrated to actively target diseased sites and successfully deliver plasmid DNA, proteins and other therapeutic agents into mammalian cells. These disease-targeting bacteria can be employed for targeted delivery of therapeutic and imaging cargos in the form of a bio-hybrid system. The bio-hybrid drug delivery system constructed here is comprised of motile Escherichia coli MG1655 bacteria and elliptical disk-shaped polymeric microparticles. The transport direction for these vehicles can be controlled through biased random walk of the attached bacteria in presence of chemoattractant gradients in a process known as chemotaxis. In this work, we utilize a diffusion-based microfluidic platform to establish steady linear concentration gradients of a chemoattractant and investigate the roles of chemotaxis and geometry in transport of bio-hybrid drug delivery vehicles. Our experimental results demonstrate for the first time that bacterial chemotactic response dominates the effect of body shape in extravascular transport; thus, the non-spherical system could be more favorable for drug delivery applications owing to the known benefits of using non-spherical particles for vascular transport (e.g. relatively long circulation time).


BacteriaBots Drug delivery Bacterial chemotaxis Microfluidics Particle shape