Yun Jung Heo

Continuous glucose monitoring (CGM) allows patients with diabetes to manage critical disease effectively and autonomously and prevent exacerbation. A painless, wireless, compact, and minimally invasive device that can provide CGM is essential for monitoring the health conditions of freely moving patients with diabetes. Here, we propose a glucose-responsive fluorescence-based highly sensitive biodegradable microneedle CGM system. These ultrathin and ultralight microneedle sensor arrays continuous

Continuous glucose monitoring (CGM) sensors have led a paradigm shift to painless, continuous, zero-finger pricking measurement in blood glucose monitoring. Recent electrochemical CGM sensors have reached two-week lifespans and no calibration with clinically acceptable accuracy. The system with the recent CGM sensors is identified as an “integrated glucose monitoring system,” which can replace finger-pricking glucose-testing for diabetes treatment decisions. Although such innovation has brought

This work presents self-focusing 3D lithography based on the refractive index changes of polyethylene glycol diacrylate (PEGDA) during photopolymerization. Since the polymerization of PEGDA leads to an increase in the refractive index, the UV light rays in the PEGDA undergo a refraction effect during exposure, thus being focused and forming 3D photopolymerized structures. We demonstrate the potential of self-focusing 3D lithography by fabricating PEGDA microneedles and trapezoid-shaped microwell

In this study, we present the development of an innovative electrochemical biosensor integrated into a microneedle-based system for non-invasive and sensitive quantification of cholesterol levels in interstitial fluid (ISF). The biosensor employs a graphene-based electrode with a polyelectrolyte interlayer to immobilize cholesterol oxidase (ChOx), enabling selective cholesterol detection. Graphene oxide is electrochemically reduced to form a conductive layer, and PANI is chosen as the optimal po

Hypoxia plays an essential role in the pathogenesis of various liver diseases, and albumin is one of the important biomarkers secreted by the liver. In this study, we developed an albumin monitoring system composed of hepatic hypoxia-on-a-chip and an albumin sensor to study liver function change due to hypoxia. In hepatic hypoxia-on-a-chip, we vertically stack an oxygen-scavenging channel on a liver on a chip with a thin gas-permeable membrane in the middle. This unique design of the hepatic hyp

Various accidents caused by alcohol consumption have recently increased in prevalence and have become a huge social problem. There have been efforts to identify drunk individuals using mobile devices; however, it is difficult to apply this method to a large number of people. A promising approach that does not involve wearing any sensors or subject cooperation is a markerless, vision-based method that only requires a camera to classify a drunk gait. Herein, we first propose a markerless, vision-b

A stretchable cell culture platform in which elastic micropneumatic actuators are embedded has been developed. By using the softlithography of polydimethylsiloxane (PDMS), the platform can be fabricated to any size and shape. It also permits cell culture by using the same standard methods that one would use with a Petri dish and it is transparent, permitting optical inspection of the cells. Thus, the platform is promising for studying cell responses because of mechanical stimulus. In this report

This paper presents the design, fabrication, and the characterization of a stretchable substrate, achieving the change of intracellular calcium ion concentration by mechanical stress. We propose the stretchable substrate integrated with the air chambers of the pneumatic actuator. We have measured the areal strain depending on input pressure and the intracellular calcium ion concentration increase in response to the mechanical stress. The present stretchable substrate is able to provide the areal

Fluorescence-based implantable glucose sensors can provide continuous glucose monitoring (CGM) with wireless transdermal transmission and long-lasting activity in vivo. Here, we present a long-term in vivo glucose monitoring method using glucose-responsive fluorescent hydrogel fibers. The fiber structure enables the sensor to remain at an implantation site for a long period and be removed from the implantation site after use. We found that the polyethylene glycol (PEG)-bonded polyacrylamide (PAA

Polyacrylamide (PAM) hydrogels are widely used in bioanalysis and biosensing applications. Scaling down of PAM patterns to micro/nanosize extends PAM applications to lab-on-a-chip, highly sensitive biosensors and cell/tissue analysis. Proposed is a replica moulding technique to pattern the PAM surface down to nanosize. Various patterns on silicon moulds successfully transferred to PAM with a minimum dimension of 60 nm and aspect ratio of up to ∼9. PAM is characterised as a platform for a single

We present a simple, fast nanochannel fabrication technique to develop hundred nanometer sized channels based on two-photon direct laser writing. By controlling laser power and location of a focused beam, we fabricated nanolines having minimum width of 180 nm. We also obtained nanochannels in the area of 110 μm × 25 μm by laser-writing with process time of 1 hour and verified rhodamine solution flowed into the nanochannels of 400 nm in width. Furthermore, this process can add desired nanochannel

Glowing glucose sensors, or so-called smart tattoos, have garnered attention because the sensors implanted under the skin can help people with diabetes monitor their blood glucose levels in a convenient, less-invasive manner. If the sensors meet their promise, life for diabetic patients can be significantly improved. Shoji Takeuchi and Yun Jung Heo review on page 43 the efforts to develop glucose biosensors and discuss their current status and future prospects.