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The globalization of drug trade has led to the increased production of falsified medicines. In addition, poor medication adherence increases the costs of healthcare. The need to manage medication has given rise to marketing of highly functional networked digital medicine. Therefore, a growing need has emerged to ensure the traceability of pharmaceutical products from shipment to patient distribution. Microtaggant technologies that can encode individual numbers on pharmaceutical products are expected to serve achieving this goal. Taggants are a class of materials that can be applied to an object to make it identifiable, like barcodes and holograms. Since the smaller size of microtaggant make it invisible to naked eyes, it is more difficult to reverse-engineer than conventional taggants. The U.S. Food and Drug Administration (FDA) has established guidelines for the use of microtaggants. Many studies have explored the use of various analytical technologies and materials as the microtaggants. However, the advantages and disadvantages of each method have not been established yet. In this review, recent research on the use of microtaggants for anti-counterfeiting is summarized and compared to current anti-counterfeiting technologies with spectrographic methods, distribution management systems with barcodes, and medication management systems with sensor devices. We also discuss the microtaggants implementation costs and security level.

The electrochemical Ni deposition at a platinum electrode was investigated in a plating nickel bath in the presence and absence of ethylene glycol (EG) using fluorescence yield soft X-ray absorption spectroscopy (FY-XAS) in the Ni L2,3-edge and O K-edge regions under potential control. At ≤+0.35 V vs. the reversible hydrogen electrode (RHE), the electrochemical Ni deposition was detected by the Ni L2,3-edge FY-XAS in the presence of EG whereas almost no such event was observed in the absence of EG. A drastic decrease of FY-XAS intensities in the O K-edge region was also observed in the presence of EG at >+0.35 V vs. RHE, suggesting that the nano-/micro-structured Ni deposition initiated by the removal of water molecules occurs on the Pt electrode. The complex formation of Ni2+ with EG and the adsorption of EG on the Ni surface could play an important role in the Ni deposition. This study demonstrates that the in situ FY-XAS is a powerful and surface-sensitive technique to understand (electro)chemical reactions including polyol synthesis and electrocatalysis at solid–liquid interfaces.

Physically unclonable functions (PUFs) are often used as robust anti-counterfeiting labels because they have fingerprints of device element characteristics due to the variations and fluctuations in the dimensional accuracy during manufacturing. An individual fingerprint can become a powerful tool against counterfeiting. Nanobeacons (NBs) with embedded Raman reporters show strong intensity enhancement, stealth performance, and long-term chemical stability. In this study, we demonstrated authenticity judgment using a chemical PUFs based on the NBs, mobile Raman detector, and a smartphone. It can be applied in the form of an ink, and it can be seen that the NBs are randomly distributed in space. By changing the embedded reporter molecule, it was shown that the NBs tracking, and imaging are possible with multicolor coating. Authentication experiments verified the security of the chemical PUFs tracers, robustness, convenience and ease of use. The chemical PUFs tracers and authenticity system could become a state-of-the-art platform to realize unbreakable anti-counterfeiting.

A transparent, optically observable microfluidic device for microwave-induced chemical reactions using 24.125 GHz ISM band incorporating was developed. The microfluidic channels can pass through gaps in the post-wall waveguide. The post-wall waveguide allows microwave irradiation to be applied to designed area of the microfluidic channel. In this study, Polydimethylsiloxane (PDMS), commonly used in microfluidic devices, was used as the microwave waveguide material. A glass plate sputtered with indium tin oxide was used to shield microwave leakage to the top and bottom. 4 W of microwave input power was used to heat ethylene glycol, which is used as a solvent in chemical synthesis, in the channels of the fabricated device, and a temperature rise to 100 °C was observed in 70 s. We believe that the use of PDMS as a waveguide material will facilitate observation during microwave irradiation using optics and combination with other microreactors.

Microtaggant technologies can encode individual numbers on coating tablet to authenticate pharmaceutical products and, therefore, combat the global spread of falsified medicine. In this study, a novel microtaggant, stealth nanobeacon (NB), with surface-enhanced Raman scattering (SERS) activity was applied to various coating tablets and its physical stability was evaluated. The NBs were composed of a reporter molecule (AH, adenine hydrochloride) and prepared with different sizes of gold nanoparticles (AuNPs). The NBs were directly deposited on the surface of various model coatings (e.g., hydroxypropyl cellulose, hydroxypropyl methyl cellulose, Eudragit® RS30D, ethyl cellulose). To investigate physical stability of the NB on the coating tablets, SERS spectra of the NB after friability test and acceleration test (store at 75% RH, 40 °C) were evaluated using a portable Raman spectrometer. After the friability test, there was no significant decrease in the peak intensity of the SERS signal (P

We investigated the magnetization reversal process of Ni wires fabricated on a single-crystal Y-cut 128° LiNbO 3 substrate using magnetoresistance measurement, Kerr microscopy, and micromagnetic simulation. Our study reveals the stripe-domain structure, which is originated by the competition between the shape magnetic anisotropy and additional magnetic anisotropy induced by the heterojunction, allows us to provide a pinning necessary to control the domain-wall displacement.

We investigate a novel higher-order nanostructure consisting of Au-nanoparticles-decorated polystyrene beads (AuNPs-decorated PS beads) by the application of AC electric field in a Lab-on-a-Chip scenario to serve a wide range of applications in life sciences, medical diagnosis and environmental analysis. The AC-electric-field-induced dynamic aggregate of AuNuP-decorated PS beads formed a suitable structure for surface-enhanced Raman scattering (SERS). The intensity of the SERS increased with the duration of AC-electric-field application during the aggregation process. This trend is attributed to that the novel hot-spots are formed as dimers, consisting of both AuNPs-decorated PS beads and 4, 4′-bipyridine. On the other hand, during Brownian movement processes, that have no forces derived from AC-electric-field, the SERS signal decreases with time as the dimers randomly disperse. A phenomenological analytical approach based on the dimer formation can reproduce experimental data with respect to aggregation and dispersion processes. This results in the enhancement of external controllability or AuNPs-decorated PS bead aggregation and dispersion. Furthermore, this also results in the production and exclusion of plasmonic hot-spots associated with high Raman enhancement. These results may open future avenues of research and application for strategic SERS analyte detection, in not only Lab-on-a chip for point-of-care testing, but also in-vivo sensing as well as microwave or light therapy.

There are many methods and techniques which can fabricate three dimensional structures consisting of metallic, ceramic, or plastic materials. To date, however, there are few systems which can create three dimensional structures made of composite materials. X-ray-radiolysis-induced photochemical reaction of liquid solution enables the direct synthesis of nano/micro-scale particles and their aggregates. In this study, the topography and composition of synthesized particles or aggregates are strongly dependent on substrate types dipped in aqueous solution of Cu(COOCH3)2 in X-ray radiolysis.

The competition between magnetic shape anisotropy and the induced uniaxial magnetic anisotropy in the heterojunction between a ferromagnetic layer and a ferroelectric substrate serves to control magnetic domain structures as well as magnetization reversal characteristics. The uniaxial magnetic anisotropy, originating from the symmetry breaking effect in the heterojunction, plays a significant role in modifying the characteristics of magnetization dynamics. Magnetoelastic phenomena are known to generate uniaxial magnetic anisotropy, however, the interfacial electronic states that may contribute to the uniaxial magnetic anisotropy have not yet been adequately investigated. Here, we report experimental evidence concerning the binding energy change in the ferromagnetic layer/ferroelectric substrate heterojunction using X-ray photoemission spectroscopy. The binding energy shifts, corresponding to the chemical shifts, reveal the binding states near the interface. Our results shed light on the origin of the uniaxial magnetic anisotropy induced from the heterojunction. This knowledge can provide a means for the simultaneous control of magnetism, mechanics, and electronics in a nano/microsystem consisting of ferromagnetic/ferroelectric materials.

Our recently developed non-destructive imaging technique was applied for the characterisation of nanoparticles synthesised by X-ray radiolysis and the sol-gel method. The interfacial conditions between the nanoparticles and the substrates were observed by subtracting images taken by scanning electron microscopy at controlled electron acceleration voltages to allow backscattered electrons to be generated predominantly below and above the interfaces. The interfacial adhesion was found to be dependent on the solution pH used for the particle synthesis or particle suspension preparation, proving the change in the particle formation/deposition processes with pH as anticipated and agreed with the prediction based on the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. We found that our imaging technique was useful for the characterisation of interfaces hidden by nanoparticles to reveal the formation/deposition mechanism and can be extended to the other types of interfaces.

In this paper, we report on the demonstration of a portable immunoassay system consisting of a small centrifugal microfluidic device driver (bento box) and a centrifugal microfluidic device made of polypropylene and fabricated by injection molding. The bento box consists of a cheap DC motor and an Arduino microcontroller. It has a simple structure and is the size of a bento box, that is, 150 × 150 × 100 (W × D × H) mm3. The developed device can automatically execute an enzyme-linked immunosorbent assay (ELISA) process under a steady rotating condition because it was designed based on the principle of CLOCK, which we previously presented. Here, we first executed an ELISA using a system consisting of the bento box and a device made of polydimethylsiloxane (PDMS) and compared it with a servo-controlled device driver. It was confirmed that the results of the bento box were consistent with those of the servo-controlled device driver. The limit of detection (LOD) using the bento box was 0.759 ng ml-1. Therefore, the controllability of the bento box was demonstrated. Next, we evaluated the injection-molded device through multi-step fluid control. We confirmed, through real-time observation of the device, that accurate flow control in the designed ELISA procedure was executed. Lastly, ELISA was employed for the measurements of mouse IgG using the system consisting of the bento box and the polypropylene device. The system performed all fluidic controls within 12 min; we confirmed the specificity of the system, and the LOD was 0.320 ng ml-1.

Microwave application technologies such as microwave heating, microwave assisted chemistry, etc. are of the innovative green technologies. In this paper, a chip-size microwave applicator with plural microchannels is designed at 24 GHz band. It consists of the post-wall waveguide and two or more micro channels arranged among the metallic posts. This applicator realizes microwave heating at different temperatures for the microchannels embedded in the separate places. The temperature-time profiles of the applicator are examined numerically. An experimental verification is performed with microwave power sources of about 0.7 W.

Surface-enhanced Raman spectroscopy (SERS) is a sensitive vibrational spectroscopy technique that can enable fast and non-destructive detection of trace molecules. SERS substrates are critical for the advancement of the SERS application. By incorporating SERS substrates into microfluidic devices, the function of microfluidic devices can be extended, and an efficient on-site trace analysis platform with powerful sensing capabilities can be realized. In this paper, we report the fabrication of a rapid and sensitive optofluidic SERS device using a unique Au nanorod array (AuNRA) with a plasmon resonance frequency in the near IR region. The highly stable and reproducible AuNRA were fabricated by a facile dynamic oblique angle deposition technique. A typical spectrum of 4,4-bipyridine (BPY) with enhanced peaks was observed within a few seconds after the injection of an aqueous solution BPY. Time-course measurements revealed an outstandingly quick response of SERS in this system. Using the AuNR microfluidic device, approximately 2x10-12 mole molecules were enough to produce detectable SERS signals. This work demonstrates rapid and sensitive chemical sensing using an optofluidic device equipped with a unique noble metal nanorod array., Comment: 6 Figures

We report magnetic domain formation control within micro-scale polycrystalline Ni wires on a single-crystal Y-cut 128° LiNbO3 substrate. X-ray magnetic circular dichroism photoemission electron microscopy (XCDM-PEEM), micromagnetic simulations, and magnetoresistance (MR) measurements allowed us to estimate the uniaxial magnetic anisotropy induced by the magnetoelastic effect that originated at the interface between each Ni layer and the LiNbO3 substrate. Comparison of the XMCD-PEEM and MR measurement results shows that the competition between the shape magnetic anisotropy and the uniaxial magnetic anisotropy parallel to the orientation flat (OF) direction of the substrate leads to variations in both the magnetization order and the magnetization reversal process. The uniaxial magnetic anisotropy is estimated to be approximately 3.3 kJ/m3. This heterojunction structure composed of ferromagnetic and ferroelectric layers thus offers alternative ways to produce artificial functional multiferroic materials and devices.