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Well-ordered bioreceptors on atomically flat Au surfaces can be a high-performance biosensor. Cardiac troponin I proteins (cTnIs) have been regarded as a specific biomarker for acute myocardial infarction (AMI). Here, we report the accurate detection of cTnIs using an aptamer-immobilized Au nanoplate platform. The single-crystalline and atomically flat Au nanoplate was characterized by atomic force microscopy. For the precise detection of cTnI, we immobilized an aptamer that can strongly bind to cTnI onto an atomically flat Au nanoplate. Using the aptamer-immobilized Au nanoplate, cTnIs were successfully detected at a concentration of 100 aM (2.4 fg/mL) in buffer solution. Furthermore, cTnIs in serum could be identified at a concentration of 100 fM (2.4 pg/mL). The total assay time was ~7 h. Importantly, the aptamer-immobilized Au nanoplate enabled us to diagnose AMI patients accurately, suggesting the potential of the present method in the diagnosis of AMI.

Antibiotic-resistant bacteria present a global threat because the infections they cause are difficult to treat. Therefore, it is highly important to develop advanced methods for the identification of antibiotic resistance gene in the virulent bacteria. Here, we report the development of novel nanoprobes for fluorescence in situ hybridization (FISH) and the application of the nanoprobe to the detection of ampicillin-resistant Escherichia coli. The nanoprobe for FISH was synthesized by the modified sol–gel chemistry and the synthesized nanoprobe provided strong fluorescent signals and pH stability even under natural light condition. For the double-identification of bacteria species and ampicillin-resistance with a single probe in situ, the nanoprobes were conjugated to the two kinds of biotinylated probe DNAs; one for E. coli-species specific gene and the other for a drug-resistant gene. By using the nanoprobe-DNA conjugants, we successfully detected the ampicillin-resistant E. coli through the FISH technique. This result suggests the new insight into light stable FISH application of the nanoprobe for a pathogenic antibiotic-resistance bacterium.

Wearable devices are becoming widespread in a wide range of applications, from healthcare to biomedical monitoring systems, which enable continuous measurement of critical biomarkers for medical diagnostics, physiological health monitoring and evaluation. Especially as the elderly population grows globally, various chronic and acute diseases become increasingly important, and the medical industry is changing dramatically due to the need for point-of-care (POC) diagnosis and real-time monitoring of long-term health conditions. Wearable devices have evolved gradually in the form of accessories, integrated clothing, body attachments and body inserts. Over the past few decades, the tremendous development of electronics, biocompatible materials and nanomaterials has resulted in the development of implantable devices that enable the diagnosis and prognosis through small sensors and biomedical devices, and greatly improve the quality and efficacy of medical services. This article summarizes the wearable devices that have been developed to date, and provides a review of their clinical applications. We will also discuss the technical barriers and challenges in the development of wearable devices, and discuss future prospects on wearable biosensors for prevention, personalized medicine and real-time health monitoring.

Au nanostructures (Au NSs) have been considered promising materials for applications in fuel cell catalysis, electrochemistry, and plasmonics. For the fabrication of high-performance Au NS-based electronic or electrochemical devices, Au NSs should have clean surfaces and be directly supported on a substrate without any mediating molecules. Herein, we report the vapor-phase synthesis of Au NSs on a fluorine-doped tin oxide (FTO) substrate at 120 °C and their application to the electrocatalytic methanol oxidation reaction (MOR). By employing AuCl as a precursor, the synthesis temperature for Au NSs was reduced to under 200 °C, enabling the direct synthesis of Au NSs on an FTO substrate in the vapor phase. Considering that previously reported vapor-phase synthesis of Au NSs requires a high temperature over 1000 °C, this proposed synthetic method is remarkably simple and practical. Moreover, we could selectively synthesize Au nanoparticles (NPs) and nanoplates by adjusting the location of the substrate, and the size of the Au NPs was controllable by changing the reaction temperature. The synthesized Au NSs are a single-crystalline material with clean surfaces that achieved a high methanol oxidation current density of 14.65 mA/cm2 when intimately supported by an FTO substrate. We anticipate that this novel synthetic method can widen the applicability of vapor-phase synthesized Au NSs for electronic and electrochemical devices.

We designed a high-sensitivity magnetic resonance imaging contrast agent that could be used to diagnose diseases. First, magnetic nanocrystals were synthesized by a thermal decomposition method on an organic solvent to obtain a high magnetism and methoxy poly(ethylene glycol)-poly(lactic acid) as an amphiphilic polymer using the ring-opening polymerization method to stably disperse the magnetic nanocrystals in an aqueous phase. Subsequently, the magnetic nanoclusters simultaneously self-assembled with methoxy poly(ethylene glycol)-poly(lactic acid) using the nano-emulsion method to form magnetic nanoclusters. Because their shape was similar to a raspberry, they were named PEGylated magnetic nano-assemblies. The PEGylated magnetic nano-assemblies were dispersed stably in the aqueous phase with a uniform size of approximately 65–70 nm for an extended period (0 days: 68.8 ± 5.1 nm, 33 days: 69.2 ± 2.0 nm, and 44 days: 63.2 ± 5.6). They exhibited both enough of a magnetic resonance (MR) contrast effect and biocompatibility. In an in vivo study, the PEGylated magnetic nano-assemblies provided a high contrast effect for magnetic resonance images for a long time after one treatment, thereby improving the diagnostic visibility of the disease site.

A silver nanoparticle is one of the representative engineered nanomaterials with excellent optical, electrical, antibacterial properties. Silver nanoparticles are being increasingly used for medical products, water filters, and cosmetics, etc. However, silver nanoparticles are known to cause adverse effects on the ecosystem and human health. To utilize silver nanoparticles with minimized negative effects, it is important to understand the behavior of silver nanoparticles released to the environment. In this study, we compared toxicity behaviors of citrate-stabilized silver nanoparticles with polyethylene glycol coated silver nanoparticles in two different ionic environments, which are aquatic environments for developing zebrafish embryo. Depending on the composition of the ionic environment, citrate-stabilized silver nanoparticles and polyethylene glycol coated silver nanoparticles exhibited different behaviors in dissolution, aggregation, or precipitation, which governed the toxicity of silver nanoparticles on zebrafish embryos.

We suggest a convenient nanoemulsion fabrication method to create hyaluronan (HA)-based nanohydrogels for effective transdermal delivery. First, hyaluronan-conjugated dodecylamine (HA–Do) HA-based polymers to load the lipophilic agents were synthesized with hyaluronan (HA) and dodecylamine (Do) by varying the substitution ratio of Do to HA. The synthetic yield of HA–Do was more than 80% (HA–Do (A): 82.7 ± 4.7%, HA–Do (B): 87.1 ± 3.9% and HA–Do (C): 81.4 ± 4.5%). Subsequently, nanohydrogels were fabricated using the nanoemulsion method. Indocyanine green (ICG) simultaneously self-assembled with HA–Do, and the size depended on the substitution ratio of Do in HA–Do (nanohydrogel (A): 118.0 ± 2.2 nm, nanohydrogel (B): 121.9 ± 11.4 nm, and nanohydrogel (C): 142.2 ± 3.8 nm). The nanohydrogels were delivered into cells, and had excellent biocompatibility. Especially, nanohydrogel (A) could deliver and permeate ICG into the deep skin layer, the dermis. This suggests that nanohydrogels can be potent transdermal delivery systems.