This study introduces a new concept for a simple, efficient and cheap sensitivity amplification of a Quartz Crystal Microbalance (QCM) based immunosensor system for the detection of tumor necrosis factor-alpha (TNF-α, TNF) by using an in-built magnetic system. The frequency shift due to the applied magnetic field was successfully observed on magnetic particles labeled detection antibodies, anti-human TNF-α, which were bound to the immunologically captured TNF-α on the gold coated quartz crystals. In the present system, the magnitude of frequency shift depends on both the strength of magnetic field and the amount of target antigen applied. Significant signal amplification was observed when the additional built-in residual stress generated by the modified magnetic particles under the magnetic field applied. Used in conjunction with a sandwich type non-competitive immunoassay format, the lower detection limit was calculated to be 25 ngmL −1 and showed good linearity up to TNF-α concentrations as high as 2.0 µgmL. The sensitivity, most importantly, was improved up to 4.3 times compared with the same QCM system which was used only an antigen-antibody binding without additional magnetic amplification.
Abstract. This paper presents a fabrication method of microcapsules encapsulating fluorescent nanoparticles sensitive to an organic liquid, which is potentially applicable to the encapsulation of protein, cell and drug. It uses the supra-molecular self-assembly of a block copolymer at the interface of the stable and controllable droplets of water suspended with fluorescent nanoparticles and the polymer solved organic. The size and uniformity of the microcapsules were examined for the various polymer concentrations by using SEM image analysis. The maximum standard deviation of the produced microcapsules of less than 3.5% was obtained from the microcapsules produced from the same conditions. The inclusion of fluorescent nanoparticles was visualized in the fluorescence microscope and by using TEM image. It is shown that this fabrication method can provide the uniform size microcapsules with a higher inclusion.
Abstract. This paper presents a novel direct fabrication method of the thin metal film RTD temperature sensor array on an arbitrary curved surface by using MEMS technology to measure a distributed temperature field up to 300 o C without disturbing a fluid flow. In order to overcome the difficulty in the three dimensional photography of sensor patterning, the UV pre-irradiated photosensitive dry film resist technology has been developed newly. This method was applied to the fabrication of the temperature sensor array on a glass tube, which is arranged parallel and transverse to a main flow. Gold was used as a temperature sensing material. The resistance change was measured in a thermally controlled oven by increasing the environmental temperature. The linear increase in resistance change and a constant slope were obtained. Also, the sensitivity of each RTD temperature sensor was evaluated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.