Modification of a Substrate Roughness for a Fabrication of Freestanding Electroplated Metallic Microstructures

This study aims to demonstrate a simple fabrication technique of freestanding electroplated metallic microstructures by modifying a substrate roughness. The proposed technique utilizes counter effects between two forces, i.e. an intrinsic force causing shrinkage in an electroplated metallic microstructure, and an adhesive force adhering a metallic microstructure to a substrate. With the modification of substrate roughness until the adhesive force becomes weaker than the induced intrinsic force, electroplated metallic microstructures would spontaneously release from the substrate after the electroplating process. Three parameters, i.e. substrate roughness, electroplated square structure's area and electroplated rectangular structure's width-to-length ratio, were experimentally studied. The results showed that the electroplated structure with a smaller size and smaller width-to-length ratio was more easily detached from the substrate for a given substrate roughness. In addition, for the same electroplated structure, a substrate with less roughness allowed a detachment of electroplated microstructure more easily

Polymeric Nanocomposite-Based Agriculture Delivery System: Emerging Technology for Agriculture

The increasing global population has forced the agricultural area to enhance the yield of crop, thereby fulfilling the requirements of people. The advancement has led to synthesis of nanomaterials with different size, shapes, and biocompatibility aspects towards specific applications like agriculture. Several nanomaterials such as metal, metal oxide, carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene, and its derivatives have shown potential ability for augmenting the yield of crops and protect crops against pathogens. However, these nanomaterials required smart delivery system that might easily deliver the nanofertilizers in a controlled manner. In this context, the incorporation of nanotechnology and polymer science might be developing newer technology with minimal usage and maximum effectiveness for improvement of crops. The incorporation of nanomaterials in polymeric composites offers newer approaches for agricultural delivery system that might provide various advantages such as higher stability, solubility, uniform distribution, and controlled release. Moreover, nanomaterials have potential ability for advancement in the genetic engineering. Herein, we discuss the role of nanomaterials in the growth of the plant, polymeric nanocomposite materials for agriculture delivery system with the advancement in the genetic engineering, and future prospects of these polymeric-nanocomposite materials in agriculture

Filling-and-Dragging Technique for A Particle-Entrapment Using Triangular Microwells

Trapping particle such as a cell, cell spheroid or scaffold bead, in a large trapping spot, such as a microwell, is important in various biological aspects. To achieve high trapping efficacy, the management of two countering effects from hydrodynamic and gravitational force is a key requirement. To increase the possibility of controllable entrapment, this study proposed a new approach using the filling and dragging technique to trap particles. The investigation of the trapping efficacy in three different triangular microwells such as obtuse, equilateral and acute triangle was conducted. The extremely low flow rate was firstly introduced to fill the particles in the microwell, and the flow rate was subsequently increased to drag and rearrange the entrapped particles. High trapping rate of a single particle in an equilateral triangular microwell could reach 80% when trapping polystyrene beads. For biomaterial particle such as cell spheroid, the adhesiveness with the other and the microwell surface is the parameter that needs to be further investigated

Review on Micro- and Nanolithography Techniques and Their Applications

This article reviews major micro- and nanolithography techniques and their applications from commercial micro devices to emerging applications in nanoscale science and engineering. Micro- and nanolithography has been the key technology in manufacturing of integrated circuits and microchips in the semiconductor industry. Such a technology is also sparking a magnificent transformation of nanotechnology. The lithography techniques including photolithography, electron beam lithography, focused ion beam lithography, soft lithography, nanoimprint lithography and scanning probe lithography are discussed. Furthermore, their applications are reviewed and summarized into four major areas: electronics and microsystems, medical and biotech, optics and photonics, and environment and energy harvesting

Separation of magnetic particles using an array of magnets - A model of a separation device for malaria-infected blood cells

Our ultimate goal is to design, fabricate, and test a new platform for malaria diagnosis using an array of magnets located parallel to a straight microchannel. The principle of the diagnosis is to attract malaria-infected blood cells using a nonuniform magnetic field induced by the array of magnets, while healthy blood cells are not affected and move along the flow direction. To achieve the goal, a mathematical model for predicting blood-cell motion was developed and validated using magnetic particles. In the experiments, trajectories of magnetic particles were captured using a photographic technique as the particles moved inside the system. The study has revealed that the trajectories of the magnetic particles obtained from both computational and experimental results were in a good agreement, and the mean deviation between them was around 18% for both 5 and 10 μm magnetic particles. In addition, the simulation results for malaria-infected mouse blood cells suggested that at the distance of 400 μm from the magnet array, the infected blood cells could move laterally toward the magnet array at distances around 35.2, 26.9, 21.8, and 18.3 μm within a 3 cm downstream distance at flow rates of 0.18, 0.23, 0.28, and 0.33 μL/min, respectively.</p

Plasmonic Nearfield Scanning Probe with High Transmission

Nearfield scanning optical microscopy (NSOM) offers a practical means of optical imaging, optical sensing, and nanolithography at a resolution below the diffraction limit of the light. However, its applications are limited due to the strong attenuation of the light transmitted through the subwavelength aperture. To solve this problem, we report the development of plasmonic nearfield scanning optical microscope with an efficient nearfield focusing. By exciting surface plasmons, plasmonic NSOM probes are capable of confining light into a 100 nm spot. We show by nearfield lithography experiments that the intensity at the near field is at least one order stronger than the intensity obtained from the conventional NSOM probes under the same illumination condition. Such a high efficiency can enable plasmonic NSOM as a practical tool for nearfield lithography, data storage, cellular visualization, and many other applications requiring efficient transmission with high resolution