Mechanochromic polymers change their colors upon different stimuli such as force, heat, and pH change. Among them, polydiacetylene detects forces by the twist of its backbone, thus is highly sensitive. Its amphiphilic structure allows for the integration inside biological membranes, opening a potential as a membrane force sensor. In this article, we will introduce our recent efforts in understanding the force-sensing mechanism of polydiacetylene.
Air pollution and its negative health consequence have been a serious issue in India, and the large source is brick kiln. Brick has long been used in India and it is producing 250 billion bricks annually. While burnt brick is a cause of air pollution, it plays an important role as affordable building material in improving people’s living environment in India with the second largest population of 1.3 billion people. In order to reduce air pollution from brick sector, this paper conducts comprehensive analysis of factors that discourage air pollutant emission reduction from brick sector in India.
Photoactive Yellow Protein (PYP) is a 125-residue photoreceptor protein that contains p-coumaric acid (pCA) as the active center. In the early stages of the photoreaction cycle, the pCA undergoes the trans-cis isomerization reaction. In order to understand mechanism of the photo-isomerization reaction by the electronic structure, the canonical molecular orbital calculation of pCA and the 35-residue model was carried out. We observed the molecular orbitals involved in the photo-isomerization reaction, which was spreading into the surrounding proteins from the active site.
In recent years, bio-assembly methods through microtissues have been highlighted in biomedical science and industry. Among various bio-assembly methods, cell fibers possess high handleability and capability of fabricating tissues on a three-dimensional scale which have potentials in such applications as bioreactors. However, due to the outbreak of Covid-19, studies on cell fibers done in laboratories are getting restricted, slowing down the development of this technology. Here we suggest a simple and cost-effective method to fabricate cell fibers at home by using a microfluidic device with double-coaxial laminar flow which is printed by a low-cost 3D printer. We also showed a demonstration of our homemade cell fibers functions as a bioreactor.
This paper presents a novel fabrication method of biodegradable porous microneedles (MNs) for pain-free interstitial fluid (ISF) extraction from the skin. Biodegradable polylactic acid (PLA) microspheres prepared by single emulsion were used to fill MNs in order to form continuous capillaries directly. Subsequently, heat treatment was implemented to bond microspheres together to produce interconnected micropores and robust porous structures. The results demonstrated that the extraction performance by capillary effect and skin penetration of MNs improved greatly after the heat treatment. With the proposed fabrication method, mass production of porous MNs can be achieved and furthermore, early diagnosis of diseases can be realized by integrating biosensors.
Microneedle (MN) is a micron scale needle to bypass the stratum corneum for subsequent biomedical applications in epidermis and dermis layers of the skin. In terms of the biocompatibility and biodegradability, polylactic acid (PLA) is a safe material for MNs. In this research, PLA needles with predesigned structures were additively deposited by fused deposition modeling (FDM). Furthermore, isotropic chemical etching was employed to reduce the size of PLA needles to a micron scale to achieve the PLA MNs. PLA MNs fabricated in this work are expected to be coated with drug for medical applications.
Numerical blood flow simulation computes the blood flow state inside the living body by solving the governing equation of fluid dynamics and is used for diagnosis and surgical planning of vascular disease. However, because of the requirement of specialized knowledge, numerical simulation can be difficult to employ in medical practice without engineers. On the other hand, vascular networks usually have complicated anatomical structures that make it difficult for surgeon and patients to share information. In this research, we have developed a system that can dynamically remap the calculation results of 1D-0D simulation, which is a reduced dimension simulation method, to the patient-specific 3D blood vessels models and display them on the virtual reality display Oculus Rift.
We herein report a chemosensor array for the detection of sulfur-containing amino acids （SCAAs） that play crucial roles in maintaining the homeostasis of organisms in our bodies. The chemosensor array was fabricated using two offthe-shelf coumarin dyes and a zinc（II） ion, which showed various optical changes by adding SCAAs. With pattern recognition techniques, the chemosensor array succeeded in the simultaneous multi-SCAAs recognition and the quantitative detection of SCAA in human blood serum. We believe that the proposed chemosensor array could be used as an easy-to-handle analytical method for biological samples.
Raw materials used for producing concrete, such as sand and gravel, are in short supply worldwide. It has been reported that the production of cement, one of the main constituents of concrete, results in the emission of a large amount of CO2, accounting for 8% of total global CO2 emissions. In this study, we developed a method to produce a construction material using only sand as the solid raw material. By utilizing a technique to produce organic silicon material from sand, we placed sand, alcohol, and catalyst in a closed vessel and heated it to 240 °C. After 24 h, the sand particles were bonded to each other, and a hardened body was formed. A tradeoff in production conditions, such as temperature, time, and the amount of sand, was confirmed.