Combating COVID-19-The role of robotics in managing public health and infectious diseases.

COVID-19 may drive sustained research in robotics to address risks of infectious diseases.

3D microdevices that perform sample purification and multiplex qRT-PCR for early cancer detection with confirmation of specific RNAs.

MicroRNA expression analysis is an important screening tool for the early detection of cancer. In this study, we developed two portable three-dimensional microdevices for multiple singleplex RNA expression analysis by microRNA purification and qRT-PCR as a prototype for point-of-care testing. These microdevices are composed of several types of modules termed 'chemical IC chips'. We successfully reduced the heating area and fluorescence observation area, reduced the energy required for the reaction, and improved the portability of all systems in the devices. The purification microdevice could purify the microRNA from the sample using the FTA elute card system. The disposable reactor module mounted on both devices was easily fabricated by deforming a 100-µm-thick polypropylene film using an uncomplicated procedure. The qRT-PCR microdevice could perform reactions for samples of small volume. We purified microRNA from the HepG2 liver cancer cell line using the purification microdevice and confirmed the expression level of miR-224, which is a potential biomarker for liver cancer. Furthermore, we observed an increase in the fluorescence intensity when we performed qRT-PCR in the qRT-PCR microdevice. Therefore, the two developed microdevices show promise as a new portable tool for early cancer detection.

Modeling and measurement of curing properties of photocurable polymer containing magnetic particles and microcapsules.

In microstereolithography, three-dimensional microstructures are created by scanning an ultraviolet laser on a photocurable resin and stacking several such layers to form the desired structure. By mixing different types of particles in the resin, the formed microstructures exhibit various physical properties. For example, the magnetism and density of the microstructure can be controlled by adding magnetic particles and microcapsules to the resin. This method has been used to fabricate magnetic micromachines. Although such functional resins are useful, the incorporated magnetic particles and microcapsules can affect the fabrication resolution, making it difficult to fabricate microstructures with high precision. Thus, it is necessary to understand the effects of such microparticles and microcapsules on the fabrication process. In this study, we propose a simple model of curing resins containing magnetic particles and microcapsules to explain the effects of the magnetic particles and microcapsules. The proposed model can explain the observed curing characteristics of a resin that contains particles for all concentrations as well as for different types of magnetic particles and microcapsules. Finally, using the proposed model, we discuss how to improve the characteristics of resins containing microparticles to realize the high-resolution fabrication of three-dimensional microstructures with desirable material properties.

The development of real-time PCR micro device with optical sensor for early detection of cancer.

We can detect cancer in the early stages by validating the expression of cancer specific nucleic acids in the blood. In this report, we have developed the micro device for performing real-time polymerase chain reaction (real-time PCR), one of the methods used for determining the quantity of nucleic acids, using a small volume of reagent. This all-in-one device can perform real-time PCR with the inclusion of heating control and the analyzing system with optical sensor.

Electrospray deposition and direct patterning of polylactic acid nanofibrous microcapsules for tissue engineering.

Electrospun nanofibers composed of biodegradable polymers are attractive candidates for cell culture scaffolds in tissue engineering. Their fine-meshed structures, resembling natural extracellular matrices, effectively interact with cell surfaces and promote cell proliferation. The application of electrospinning, however, is limited to two-dimensional (2D) or single tube-like scaffolds, and the fabrication of arbitrary three-dimensional (3D) scaffolds from electrospun nanofibers is still very difficult due to the fibers' continuous and entangled form. To address this issue, in this paper, we describe the use of phase-separation-assisted electrospray and electrostatic focusing to perform continuous direct 3D patterning of nanofibrous microcapsules of biodegradable polylactic acid (PLA). These microcapsules exhibit fiber-particle duality because they are composed of nanofibers suitable for cell attachment while also being easy to handle as particles for direct 3D patterning. By varying the flow rate of the polymer solution and the humidity of the electrospray atmosphere during electrospraying, the diameter of the microcapsule and its surface porosity can be controlled. The utility of the direct-patterning process is demonstrated by fabricating high-aspect-ratio microscaffolds and subsequent cell cultures. The nanofibrous and hollow structure of the microcapsules combined with the direct 3D patterning process offers a new approach for fabricating tailor-made scaffolds for regenerative medicine.

Embryonic body formation using the tapered soft stencil for cluster culture device.

Induced pluripotent stem (iPS) cells are expected to provide a source of tissue, a renewable cell source for tissue engineering, and a method for in vitro drug screening for patient-specific or disease-specific treatment. A simple technology by which iPS cells can be differentiated effectively and in large quantities is strongly desired. In this paper, a new device (Tapered Soft Stencil for Cluster Culture: TASCL) is proposed for the easy and efficient formation of EBs which can be used in regenerative medicine. This device was compared with the two major methods currently being evaluated, namely the HD method and the Terasaki® plate (MWC substitution), in terms of the efficiency, morphology and acquired number of EB formation. Using the TASCL device, the shape of the EBs formed was almost a perfect sphere, and the formation was also faster than for the two other methods. There was little variability in the number of cells. Moreover, EBs formed using the TASCL device had the ability to differentiate into all three germ layers, and differentiation of EBs from the TASCL culture into hepatic cells was confirmed. In conclusion, it appears that the TASCL device can be utilized for EB formation to generate cells for regenerative medicine applications.

Real three-dimensional microfabrication for biodegradable polymers: demonstration of high-resolution and biocompatibility for implantable microdevices.

We have developed a novel three-dimensional (3D) microfabrication method for biodegradable polymers. Unlike conventional processes, our process satisfies high-resolution and high-speed requirements. The system design allows us the processing of microlevel forms by stacking up melted polymers from the nozzle. We adopted a batch process to supply materials in order to eliminate the prior process that required toxic solvents. In addition, it is possible to handle almost all biodegradable thermoplastic resins by adopting this system. A single layer from the piled-up layers of extruded lines was observed to evaluate the resolution. The lateral and depth resolutions attained are 40 mum and 45 mum, respectively. Biodegradable polymers enable three-dimensional microstructures such as micropipes, microbends, and microcoil springs to be manufactured in less than 15 min. The biocompatibility of the newly fabricated structure was evaluated using a cell line (PC12). For this purpose, a small vessel, with a transparent base, was fabricated using PLA and cells were cultivated in it. The results were then compared with the results obtained using the standard method. Our system renders it possible to produce toxic-free, as well as transparent and leakage-free devices. Our system is expected to have potential applications in optimum design and fabrication of implantable devices, especially in tissue engineering.

Solid-pseudopapillary tumor of the pancreatic head causing marked distal atrophy: a tumor originated posterior to the main pancreatic duct.

We report the case of a solid-pseudopapillary tumor (SPT) of the head of the pancreas causing occlusion of the main pancreatic duct (MPD) and marked pancreatic atrophy distal to the tumor disproportionate to the tumor size. A 15-yr-old girl was diagnosed with 5-cm solid-pseudopapillary tumor of the pancreatic head with marked distal pancreatic atrophy. Endoscopic retrograde cholangiopancreatography demonstrated obstruction of the MPD in the pancreatic head. We performed a duodenum-preserving pancreatic head resection to avoid postoperative exocrine and endocrine insufficiency. The surgical specimen showed the typical gross appearance of a SPT, with only a thin rim of pancreas anterior to the tumor. We believe that this presentation results when a tumor originates posterior to the MPD. Thus, whether or not pancreatic atrophy occurs depends strongly on the anterior/posterior relationship between the enlarging tumor and the MPD. The risk of SPT causing severe pancreatic atrophy should be kept in mind to avoid irreversible pancreatic insufficiency in young females.