Bioengineered bioluminescent magnetotactic bacteria as a powerful tool for chip-based whole-cell biosensors

Abstract

This paper describes the generation of genetically engineered bioluminescent magnetotactic bacteria (BL-MTB) and their integration into a microfluidic analytical device to create a portable toxicity detection system. Magnetospirillum gryphiswaldense strain MSR-1 was bioengineered to constitutively express a red-emitting click beetle luciferase whose bioluminescent signal is directly proportional to bacterial viability. The magnetic properties of these bacteria have been exploited as "natural actuators" to transfer the cells in the chip from the reaction to the detection area, optimizing the chip's analytical performance. A robust and cost-effective biosensor for the evaluation of sample toxicity, named MAGNETOX, based on lens-free contact imaging detection, has been developed. A microfluidic chip has been fabricated using multilayered black and transparent polydimethyl siloxane (PDMS) in which BL-MTB are incubated for 30 min with the sample, then moved by microfluidics, trapped, and concentrated in detection chambers by an array of neodymium-iron-boron magnets. The chip is placed in contact with a cooled CCD via a fiber optic taper to perform quantitative bioluminescence imaging after addition of luciferin substrate. A model toxic compound (dimethyl sulfoxide, DMSO) and a bile acid (taurochenodeoxycholic acid, TCDCA) were used to investigate the analytical performance of the MAGNETOX. Incubation with DMSO and TCDCA drastically reduces the bioluminescent signal in a dose-related manner. The generation of bacteria that are both magnetic and bioluminescent combines the advantages of easy 2D cell handling with ultra sensitive detection, offering undoubted potential to develop cell-based biosensors integrated into microfluidic chips.

Predictor–Response Analysis of Fiber Optic Enzymatic Biosensors Constructed with Nonmodified E. coli BL21 (DE3) pGELAF+ Sensing 1,2-Dichloroethane

“…Bridle [3] Genetically engineering in complex lab on a chip designs Relationships to bioengineering and system performance Roda et al [19] Configuration and instrumentation Illustrates design variability Bidmanova et al [2] Cell-coating encapsulation Biocatalysis; tuning metabolic activity to the application Park et al [13] identified the significance of quenching mechanisms as related to polymer chemistry, and Fritzsche et al [6] have shown variable absorbance characteristics are a function of fluorophore concentration when using a fluorescent dye similar to this research. Reardon et al [16,18] have reviewed photoluminescence-based biosensor technology specific to environmental applications, and early research by Reardon et al [17] and Reardon and Bailey [15] reinforced the importance of identifying the metabolic state of cells during immobilization.…”

Chemostat-like microfluidic platform for highly sensitive detection of heavy metal ions using microbial biosensors

“…Because the microfluidic device makes it possible to detect very low concentrations of HMIs, the application of this approach may not be limited to the small volume of samples. In addition, we note that the microfluidic device and bacterial biosensors have remarkable potential to be a portable biosensor because not only can the microfluidic device be operated by hydrostatic heads without any external pumping system but also integrated with a portable CCD camera system (Roda et al, 2013) for fluorescent detection. It is obvious that the microbial biosensors can be synthetically engineered to produce stronger fluorescence signals in response to metal ions for enhanced sensitivity and selectivity (Wu et al, 2009).…”

Recent advances in lab-on-a-chip for biosensing applications

“…Microfluidic platforms are increasingly being used for monitoring cell activity and provide an ideal platform for the implementation of whole-cell biosensors. Roda et al (2013) took advantage of the properties of magnetotactic bacteria, using microfluidics to move the cells between the incubation and detection areas of the chip where they were trapped by an array of neodymium-iron-boron magnets. However, the fluid flows generated within microfluidic systems can generate fluid shear stress (FSS).…”