Due to the significance of hydrogen peroxide (H(2)O(2)) in biological systems and its practical applications, the development of efficient electrochemical H(2)O(2) sensors holds a special attraction for researchers Various materials such as Prussian blue (PB), heme proteins, carbon nanotubes (CNTs) and transition metals have been applied to the construction of H(2)O(2) sensors In this article, the electrocatalytic H(2)O(2) determinations are mainly focused on because they can provide a superior sensing performance over non-electrocatalytic ones The synergetic effect between nanotechnology and electrochemical H(2)O(2) determination is also highlighted in various aspects In addition, some recent progress for in vivo H(2)O(2) measurements is also presented Finally, the future prospects for more efficient H(2)O(2) sensing are discussed

Recent advances in electrochemical sensing for hydrogen peroxide: a review

Microorganisms move in challenging environments by periodic changes in body shape. In contrast, current artificial microrobots cannot actively deform, exhibiting at best passive bending under external fields. Here, by taking advantage of the wireless, scalable and spatiotemporally selective capabilities that light allows, we show that soft microrobots consisting of photoactive liquid-crystal elastomers can be driven by structured monochromatic light to perform sophisticated biomimetic motions. We realize continuum yet selectively addressable artificial microswimmers that generate travelling-wave motions to self-propel without external forces or torques, as well as microrobots capable of versatile locomotion behaviours on demand. Both theoretical predictions and experimental results confirm that multiple gaits, mimicking either symplectic or antiplectic metachrony of ciliate protozoa, can be achieved with single microswimmers. The principle of using structured light can be extended to other applications that require microscale actuation with sophisticated spatiotemporal coordination for advanced microrobotic technologies.

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Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots

A review of lithium ion battery failure mechanisms and fire prevention strategies

Graphene wrapped Cu2O nanocubes: Non-enzymatic electrochemical sensors for the detection of glucose and hydrogen peroxide with enhanced stability

Untethered robots miniaturized to the length scale of millimeter and below attract growing attention for the prospect of transforming many aspects of health care and bioengineering. As the robot size goes down to the order of a single cell, previously inaccessible body sites would become available for high-resolution in situ and in vivo manipulations. This unprecedented direct access would enable an extensive range of minimally invasive medical operations. Here, we provide a comprehensive review of the current advances in biomedical untethered mobile milli/microrobots. We put a special emphasis on the potential impacts of biomedical microrobots in the near future. Finally, we discuss the existing challenges and emerging concepts associated with designing such a miniaturized robot for operation inside a biological environment for biomedical applications.

Biomedical Applications of Untethered Mobile Milli/Microrobots

Photocatalytic activity of SnO2 nanoparticles in methylene blue degradation

A magnetic navigation system (MNS) for the wireless manipulation of micro-robots in human blood vessels is a possible surgical tool for coronary artery disease. This paper proposes a novel MNS composed of one conventional pair of Maxwell and Helmholtz coils and one newly developed pair of gradient and uniform saddle coils. The proposed system was theoretically developed using the Biot-Savart law, and it was verified experimentally after constructing the proposed MNS. The proposed MNS is geometrically compact to allow a patient to lie down, and magnetically efficient compared with the conventional MNS which has two pairs of Maxwell and Helmholtz coils.

Magnetic Navigation System With Gradient and Uniform Saddle Coils for the Wireless Manipulation of Micro-Robots in Human Blood Vessels

Various types of actuation methods for microrobots have been proposed. Among the actuation methods, electromagnetic based actuation (EMA) has been considered a promising actuation mechanism. In this paper, a new EMA system for three-dimensional (3D) locomotion and drilling of the microrobot is proposed. The proposed system consists of four fixed coil pairs and one rotating coil pair. In detail, the coil system has three pairs of stationary Helmholtz coil, a pair of stationary Maxwell coil and a pair of rotating Maxwell coil. The Helmholtz coil pairs can magnetize and align the microrobot to the desired direction and the two pairs of Maxwell coil can generate the propulsion force of the microrobot. In addition, the Helmholtz coil pairs can rotate the microrobot about a desired axis. The rotation of the microrobot is a drilling action through an occlusion in a vessel. Through various experiments, the 3D locomotion and drilling of the microrobot by using the proposed EMA system are demonstrated. Compared with other EMA systems, the proposed system can provide the advantages of consecutive locomotion and drilling of the microrobot.

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Novel electromagnetic actuation system for three-dimensional locomotion and drilling of intravascular microrobot

Reductive determination of hydrogen peroxide with MWCNTs-Pd nanoparticles on a modified glassy carbon electrode.

This paper proposes a new two-dimensional (2D) actuation method for a microrobot that uses a stationary two-pair coil system. The coil system actuates the microrobot by controlling the magnitude and direction of the external magnetic flux. The actuation of the microrobot consists of an alignment to the desired direction and a linear movement of the microrobot by non-contact electromagnetic actuation. Firstly, the actuation mechanism of the stationary coil system is theoretically derived and analyzed. Secondly, the tendency of the magnetic flux in the coil system are analyzed and compared by preliminary theoretical analysis. Through various locomotive experiments of the microrobot, the performance of the electromagnetic actuation by the proposed stationary two-pair coil system is evaluated. Using the proposed 2D actuation method, the microrobot is aligned to the desired direction by Helmholtz coils and is driven to the aligned direction by Maxwell coils. By the successive current control of the coil system, the microrobot can move along a desired path, such as a rectangular-shaped or a diamond-shaped path.

Hyun Chul Choi

Papers

Photocatalytic activity of SnO2 nanoparticles in methylene blue degradation

Magnetic Navigation System With Gradient and Uniform Saddle Coils for the Wireless Manipulation of Micro-Robots in Human Blood Vessels

Novel electromagnetic actuation system for three-dimensional locomotion and drilling of intravascular microrobot

Reductive determination of hydrogen peroxide with MWCNTs-Pd nanoparticles on a modified glassy carbon electrode.

Two-dimensional actuation of a microrobot with a stationary two-pair coil system