Laminar flow assisted anisotropic bacteria absorption for chemotaxis delivery of bacteria-attached microparticle

Abstract

The concepts of microrobots has been drawn significant attentions recently since its unprecedented applicability in nanotechnology and biomedical field. Bacteria attached microparticles presented in this work are one of pioneering microrobot technology for self-propulsion or producing kinetic energy from ambient for their motions. Microfluidic device, especially utilizing laminar flow characteristics, were employed for anisotropic attachment of Salmonella typhimurium flagellated chemotactic bacteria to 30 um × 30 um and 50 um × 50 um microparticles that made of biodegradable polymer. Any toxic chemicals or harmful treatments were excluded during the attachment process and it finished within 100 s for the anisotropic attachment. The attachments were directly confirmed by fluorescent intensity changes and SEM visualization. Chemotaxis motions were tracked using aspartate and the maximum velocity of the bacteria-attached microrobot was measured to be ~5 um/s which is comparable to prior state of art technologies. This reusable and scalable method could play a key role in chemotaxis delivery of functional microparticles such as drug delivery system.

In vitro quantitative analysis of Salmonella typhimurium preference for amino acids secreted by human breast tumor

“…After quantitative analyzing the chemotactic motion of S. typhimurium, we could conclude that S. typhimurium has strongest responsive toward the aspartic acid. This understanding chemotactic response to the cancer secreting amino acids will allow the development of bacterial therapies by utilizing the drug producible engineered bacteria or the bacteria-based micro-robot (bacteriobot) [3,4,32,33] as enhancing the speed and precisely controlling the direction of bacteria.…”

“…Bacteria have been considered as an alternative theranostic activities to overcome the chemotherapeutics barrier [1][2][3][4]. The conventional therapy using anticancer drugs, which are capable of diffusing passively, are limited by their inability to penetrate into the tumor tissue and have poor cell susceptibility [1,5,6].…”

Microfluidics for Microswimmers: Engineering Novel Swimmers and Constructing Swimming Lanes on the Microscale, a Tutorial Review

“…Huh et al are one of the rare groups to have performed effective coupling of bacteria with artificial microparticles in a microfluidic device to produce biohybrid microswimmers. [55] Their innovative approach to fabricate bacteriabots uses microfluidic devices consisting of a microchannel with V-shaped microstructure "trapper" arrays to trap cubic polymeric, biodegradable microparticles (Figure 3A). Once the microparticles are trapped, a solution of attenuated bacteria (Salmonella Typhimurium) is pumped inside the microfluidic channel.…”

“…Reproduced with permission. [55] Copyright 2016, Springer. B) Biohybrid soft microswimmers fabrication in a microfluidic capillary device and potential application of the magnetic nanoparticle embedded cell carriers.…”

Modeling of Inactivation of Biofilm Composing Bacteria with Low Intensity Electric Field: Prediction of Lowest Intensity and Mechanism

“…where E is the electric field between parallel plates, d is the distance between the plates, and ∆V is the potential difference between the plates. Bacterial cell membranes, especially those in the lipid bilayer, have anisotropic (Pogozheva et al, 2013;Huh et al, 2016) and electro-optical properties (Bunin et al, 2005), so when they interact with an external electric field, they experience a change in the refractive index (Eismann, 2012), which satisfies the Equation 2:…”