Single Cell Manipulation using Ferromagnetic Composite Microtransporters

For biomedical applications, such as single cell manipulation, it is important to fabricate microstructures that can be powered and controlled wirelessly in fluidic environments. In this letter, we describe the construction and operation of truly micron-sized, biocompatible ferromagnetic microtransporters driven by external magnetic fields. Microtransporters were fabricated using a simple, single step fabrication method and can be produced in large numbers. We demonstrate that they can be navigated to manipulate single cells with micron-size precision without disturbing the local environment

Numerical and Experimental Study on the Addition of Surface Roughness to Micro-Propellers

Micro aerial vehicles are making a large impact in applications such as search-and-rescue, package delivery, and recreation. Unfortunately, these diminutive drones are currently constrained to carrying small payloads, in large part because they use propellers optimized for larger aircraft and inviscid flow regimes. Fully realizing the potential of emerging microflyers requires next-generation propellers that are specifically designed for low-Reynolds number conditions and that include new features advantageous in highly viscous flows. One aspect that has received limited attention in the literature is the addition of roughness to propeller blades as a method of reducing drag and increasing thrust. To investigate this possibility, we used large eddy simulation to conduct a numerical investigation of smooth and rough propellers. Our results indicate that roughness produces a 2% increase in thrust and a 5% decrease in power relative to a baseline smooth propeller operating at the same Reynolds number of Rec = 6500, held constant by rotational speed. We corroborated our numerical findings using thrust-stand-based experiments of 3D-printed propellers identical to those of the numerical simulations. Our study confirms that surface roughness is an additional parameter within the design space for micro-propellers that will lead to unprecedented drone efficiencies and payloads.Comment: 23 Pages, 9 Figure

Cellular expression through morphogen delivery by light activated magnetic microrobots

Microrobots have many potential uses in microbiology since they can be remotely actuated and precisely manipulated in biochemical fluids. Cellular function and response depends on biochemicals. Therefore, various delivery methods have been developed for delivering biologically relevant cargo using microrobots. However, localized targeting without payload leakage during transport is challenging. Here, we design a microrobotic platform capable of on-demand delivery of signaling molecules in biological systems. The on-demand delivery method is based on a light-responsive photolabile linker which releases a cell-to-cell signaling molecule when exposed to light, integrated on the surface of microrobots. Successful delivery of the signaling molecules and subsequent gene regulation is also demonstrated. This proposed method can be used for multiple applications, especially in biology, engineering, and medicine where on-demand delivery of chemical cargo at targeted locations is important.ONR (Grant N00014-11-1-0725)NSF (Grants CNS-1446474 and CNS-1446592

Nematic colloidal micro-robots as physically intelligent systems

Physically intelligent micro-robotic systems exploit information embedded in micro-robots, their colloidal cargo, and their milieu to interact, assemble, and form functional structures. Nonlinear anisotropic fluids such as nematic liquid crystals (NLCs) provide untapped opportunities to embed interactions via their topological defects, complex elastic responses, and ability to dramatically restructure in dynamic settings. Here a four-armed ferromagnetic micro-robot is designed and fabricated to embed and dynamically reconfigure information in the nematic director field, generating a suite of physical interactions for cargo manipulation. The micro-robot shape and surface chemistry are designed to generate a nemato-elastic energy landscape in the domain that defines multiple modes of emergent, bottom-up interactions with passive colloids. Micro-robot rotation expands the ability to sculpt interactionsthe energy landscape around a rotating micro-robot is dynamically reconfigured by complex far-from-equilibrium dynamics of the micro-robot’s companion topological defect. These defect dynamics allow transient information to be programmed into the domain and exploited. Robust micro-robotic manipulation strategies are demonstrated that exploit these diverse modes of nemato-elastic interaction to achieve cargo docking, transport, release, and assembly of complex reconfigurable structures at multi-stable sites. Such structures are of great interest to future developments of LC-based advanced optical device and micro-manufacturing in anisotropic environments