Octopus-Inspired Soft Robot for Slow Drug Release.

Octopus tentacles are equipped with numerous suckers, wherein the muscles contract and expel air, creating a pressure difference. Subsequently, when the muscular tension is released, objects can be securely adhered to. This mechanism has been widely employed in the development of adhesive systems. However, most existing octopus-inspired structures are passive and static, lacking dynamic and controllable adhesive switching capabilities and excellent locomotion performance. Here, we present an octopus-inspired soft robot (OISR). Attracted by the magnetic gradient field, the suction cup structure inside the OISR can generate a strong adsorption force, producing dynamically controllable adsorption and separation in the gastrointestinal (GI) tract. The experimental results show that the OISR has a variety of controllable locomotion behaviors, including quick scrolling and rolling motions, generating fast locomotion responses, rolling over gastric folds, and tumbling and swimming inside liquids. By carrying drugs that are absorbable by GI epithelial cells to target areas, the OISR enables continuous drug delivery at lesions or inflamed regions of the GI tract. This research may be a potential approach for achieving localized slow drug release within the GI tract.

Microgripper Robot with End Electropermanent Magnet Collaborative Actuation.

Magnetic microgrippers, with their miniaturized size, flexible movement, untethered actuation, and programmable deformation, can perform tasks such as cell manipulation, targeted drug delivery, biopsy, and minimally invasive surgery in hard-to-reach regions. However, common external magnetic-field-driving devices suffer from low efficiency and utilization due to the significant size disparity with magnetic microgrippers. Here, we introduce a microgripper robot (MGR) driven by end electromagnetic and permanent magnet collaboration. The magnetic field generated by the microcoils can be amplified by the permanent magnets and the direction can be controlled by changing the current, allowing for precise control over the opening and closing of the magnetic microgripper and enhancing its operational range. Experimental results demonstrate that the MGR can be flexibly controlled in complex constrained environments and is highly adaptable for manipulating objects. Furthermore, the MGR can achieve planar and antigravity object grasping and transportation within complex simulated human cavity pathways. The MGR's grasping capabilities can also be extended to specialized tasks, such as circuit connection in confined spaces. The MGR combines the required safety and controllability for in vivo operations, making it suitable for potential clinical applications such as tumor or abnormal tissue sampling and surgical assistance.

Combined three dimensional locomotion and deformation of functional ferrofluidic robots.

Magnetic microrobots possess remarkable potential for targeted applications in the medical field, primarily due to their non-invasive, controllable properties. These unique qualities have garnered increased attention and fascination among researchers. However, these robotic systems do face challenges such as limited deformation capabilities and difficulties navigating confined spaces. Recently, researchers have turned their attention towards magnetic droplet robots, which are notable for their superior deformability, controllability, and potential for a range of applications such as automated virus detection and targeted drug delivery. Despite these advantages, the majority of current research is constrained to two-dimensional deformation and motion, thereby limiting their broader functionality. In response to these limitations, this study proposes innovative strategies for controlling deformation and achieving a three-dimensional (3D) trajectory in ferrofluidic robots. These strategies leverage a custom-designed eight-axis electromagnetic coil and a sliding mode controller. The implementation of these methods exhibits the potential of ferrofluidic robots in diverse applications, including microfluidic pump systems, 3D micromanipulation, and selective vascular occlusion. In essence, this study aims to broaden the capabilities of ferrofluidic robots, thereby enhancing their applicability across a multitude of fields such as medicine, micromanipulation, bioengineering, and more by maximizing the potential of these intricate robotic systems.

Third-order optical nonlinearity measurements and optical limiting experiment in Tm: YAG crystal.

In this paper, we investigate the third-order nonlinearities and optical limiting effect of Tm: YAG crystal at a wavelength of 1064 nm. We experimentally measure different energy densities (6.4, 12.8, and 19.2J/cm2) and obtain the nonlinear absorption coefficient, nonlinear refractive index, and third-order nonlinear susceptibility of Tm: YAG crystal. Z-scan results show that Tm: YAG crystal exhibits a large nonlinear absorption coefficient (3.34×10-9m/W) at the wavelength of 1064 nm. We also measure the transmittance of Tm: YAG crystals of three different lengths (7, 15, and 20 mm) to evaluate its nonlinear optical limiting performance. For the 20 mm Tm: YAG crystal, the maximum transmittance without optical limiting effect and minimum transmittance with nonlinear optical limiting effect at a 1064 wavelength nm are 84.2% and 47.8%, respectively, which indicates that Tm: YAG crystal may be a solid material for nonlinear optical limiting at 1064 nm.

Nonlinear optical limiting effect of graphene dispersions at 1064 nm.

We study the nonlinear optical limiting effect of graphene dispersions in ethanol and acetone at a wavelength of 1064 nm. The nonlinear optical limiting effect of graphene dispersion under three different linear transmittances (about 70%, 80%, and 90%), two different thicknesses (1 and 3 cm), and two different solvents (ethanol and acetone) are measured. The influences of concentration, thickness, and solvent on the nonlinear optical limiting effect of the graphene dispersion are analyzed. The experimental results show that the concentration and solution thicknesses have great influence on the optical limiting ability of graphene dispersions. The graphene dispersions with ethanol and acetone as solvents can be used to achieve excellent nonlinear optical limiting effects. The optical limiting ability of the graphene dispersion in acetone is better than that of the graphene dispersion in ethanol.

Optical limiting effect of C70 solution at 1064 nm.

In this paper, we investigate the optical limiting effect of C70 solution at a wavelength of 1064 nm. We experimentally measured the transmittance of C70 solution under three different concentrations (0.25, 0.5, and 1 mmol/L), three different solution thicknesses (5, 10, and 20 mm), and two different solvents (toluene and xylene) and obtained the values of absorption cross sections and relaxation times in the five-level absorption model of C70 solution. The influences of concentration, thickness, and solvent on the optical limiting effect of the C70 solution are analyzed. We also measured transmittance of C60 solution under the same conditions and compared the results with those of C70 solution. The experimental results show that concentration and solution thicknesses have great influence on the optical limiting ability of C70 solution. The optical limiting effect of C70 solution is better than that of C60 solution at low concentration and worse than that of C60 solution at high concentration.