Bacterial Biohybrid Microswimmers

Abstract

Over millions of years, Nature has optimized the motion of biological systems at the micro and nanoscales. Motor proteins to motile single cells have managed to overcome Brownian motion and solve several challenges that arise at low Reynolds numbers. In this review, we will briefly describe naturally motile systems and their strategies to move, starting with a general introduction that surveys a broad range of developments, followed by an overview about the physical laws and parameters that govern and limit motion at the microscale. We characterize some of the classes of biological microswimmers that have arisen in the course of evolution, as well as the hybrid structures that have been constructed based on these, ranging from Montemagno's ATPase motor to the SpermBot. Thereafter, we maintain our focus on bacteria and their biohybrids. We introduce the inherent properties of bacteria as a natural microswimmer and explain the different principles bacteria use for their motion. We then elucidate different strategies that have been employed for the coupling of a variety of artificial microobjects to the bacterial surface, and evaluate the different effects the coupled objects have on the motion of the "biohybrid." Concluding, we give a short overview and a realistic evaluation of proposed applications in the field.

Genetically Engineered Bacterial Biohybrid Microswimmers for Sensing Applications

“…Interestingly, most probiotic bacteria (e.g., Lactobacilli and Bifidobacteria) [31] and bacteria with QPS status [35] are Gram-positives. However, literature review shows that Gram-negative bacteria such as E. coli, Serratia marcescens, or Salmonella typhimurium have been widely used for the development of bacterial biohybrids, and Gram-positive bacteria have been less investigated (reviewed in [1]).…”

“…Nevertheless, today, a new field of research highlights a previously un-envisioned application of these prokaryotic microorganisms that is currently gathering momentum-their potential for the development of microswimmers. Bacterial biohybrid microswimmers usually consist of one (or many) living bacteria and one (or many) abiotic particles [1]. Depending on the bacteria-to-particle ratio, the hybrid microswimmer can be classified as a Bacteria Bot (1 bacterium:1 cargo) (examples in references [2][3][4]), a Multi Bot (1 bacterium:>1 cargoes) (examples in references [5,6]), or a Bacterial Microsystem (>1 bacteria:1 cargo) (examples in references [7,8]).…”

“…The delivery of the cargo depends on the type of bacterial locomotion. Three different active movements of bacteria have been used for the development of bacterial biohybrid microswimmers, as reviewed in reference [1]-swimming, swarming, and gliding motilities. Swimming and swarming both depend on the use of flagella [15,16].…”

Hybrid Living Materials: Digital Design and Fabrication of 3D Multimaterial Structures with Programmable Biohybrid Surfaces

“…At present, the field of biohybrid materials combines living and nonliving components with the objective of harnessing the capabilities of biological systems within structural materials . Living cells integrated into biohybrid walls, biohybrid fibers, and bio‐bots provide early examples of how such fabrications can enable a new class of uniquely responsive and multifunctional products. However, for biohybrid materials to be employed in similar manners as their industrial material counterparts, which can produce consistent outcomes on‐demand, new tools must be developed to solve problems related to replicability, scalability, and standardized control.…”

Small‐Scale Robots in Fluidic Media

“…In this study, we focus on MRs in a fluidic medium and the actuators that drive them. There are several studies reviewing MRs, capsule endoscopy, and micro/nano motors . These studies do not compare quantitively the different propulsion methods.…”