Control of magnetotactic bacterium in a micro-fabricated maze

We demonstrate the closed-loop control of a magnetotactic bacterium (MTB), i.e., Magnetospirillum magnetotacticum, within a micro-fabricated maze using a magneticbased manipulation system. The effect of the channel wall on the motion of the MTB is experimentally analyzed. This analysis is done by comparing the characteristics of the transient- and steady-states of the controlled MTB inside and outside a microfabricated maze. In this analysis, the magnetic dipole moment of our MTB is characterized using a motile technique (the u-turn technique), then used in the realization of a closed-loop control system. This control system allows the MTB to reach reference positions within a micro-fabricated maze with a channel width of 10 μm, at a velocity of 8 μm/s. Further, the control system positions the MTB within a region-of-convergence of 10 μm in diameter. Due to the effect of the channel wall, we observe that the velocity and the positioning accuracy of the MTB are decreased and increased by 71% and 44%, respectively

An ingestible capsule for the photodynamic therapy of helicobacter pylori infection

Helicobacter pylori (H. pylori) is a Gram-negative pathogen bacterium affecting the mucosa of the stomach and causing severe gastric diseases. H. pylori-related infections are currently treated with pharmacological therapies, which are associated with increasing antibiotic resistance and consequent reduction of the efficacy down to 70%-85%. Moreover, drugs have generally side effects that further affect the healthcare system in terms of additional financial and medical efforts. The aim of this study is to present an innovative device for the treatment of H. pylori infection, consisting of an ingestible lighting capsule performing photodynamic therapy by means of light at specific wavelengths. The proposed treatment is minimally invasive and the described system can be considered the first photodynamic swallowable device ever proposed. Preliminary experiments demonstrated that the capsule integrated with LED sources can provide the required lighting power to kill the bacterium with an efficiency up to about 96%

A Novel Magnetic Actuation System for Miniature Swimming Robots

A novel mechanism for actuating a miniature swimming robot is described, modeled, and experimentally validated. Underwater propulsion is obtained through the interaction of mobile internal permanentmagnets thatmove a number of polymeric flaps arranged around the body of the robot. Due to the flexibility of the proposed swimming mechanism, a different range of performances can be obtained by varying the design features. A simple multiphysics dynamic model was developed in order to predict basic behavior in fluids for different structural parameters of the robot. In order to experimentally verify the proposed mechanism and to validate the model, a prototype of the swimming robot was fabricated. The device is 35 mm in length and 18 mm in width and thickness, and the forward motion is provided by four flaps with an active length of 20 mm. The model was able to correctly predict flap dynamics, thrust, and energy expenditure for magnetic dragging within a spindle-frequency range going from 2 to 5 Hz. Additionally, the model was used to infer robot-thrust variation related to different spindle frequencies and a 25% increase in flap active length. Concerning swimming performance, the proposed technical implementation of the concept was able to achieve 37 mm/s with 4.9% magnetic mechanism efficiency