Femtosecond Laser-Induced Surface Modification and its Application

In this chapter, we present femtosecond laser micromachining to fiber optics, focusing on surface qualities. Some techniques applied in the field are introduced to date and a review of some of the current applications for this type of technology. Section 2 describes laser-induced periodic surface structures (LIPSSs), which are induced in low- and high-fluence regime. Section 3 describes the influences of laser-induced structures for the fabrication of fiber-optic sensors, with experimental techniques and results in our research group. These sections explore ultrashort laser pulses applications, roughly going from lower to higher energy (power, intensity) ones

Study of a Liquid Plug-Flow Thermal Cycling Technique Using a Temperature Gradient-Based Actuator

Easy-to-use thermal cycling for performing rapid and small-volume DNA amplification on a single chip has attracted great interest in the area of rapid field detection of biological agents. For this purpose, as a more practical alternative to conventional continuous flow thermal cycling, liquid plug-flow thermal cycling utilizes a thermal gradient generated in a serpentine rectangular flow microchannel as an actuator. The transit time and flow speed of the plug flow varied drastically in each temperature zone due to the difference in the tension at the interface between temperature gradients. According to thermal distribution analyses in microfluidics, the plug flow allowed for a slow heating process, but a fast cooling process. The thermal cycle of the microfluid was consistent with the recommended temperature gradient for PCR. Indeed, amplification efficiency of the plug flow was superior to continuous flow PCR, and provided an impressive improvement over previously-reported flow microchannel thermal cycling techniques

Electrochemical Sensing System Utilizing Simazine-Imprinted Polymer Receptor for the Detection of Simazine in Tap Water

A simazine sensing system, composed of column packed with a molecularly imprinted polymer (Sim-MIP) and an electrochemical analyzer, was scaled down in order to easily determine the concentration of simazine, an environmentally restricted chemical, in tap water. In order to enhance the detection limit, the ratio of the eluent (dilution rate) in the electrolyte was optimized to 10%. A new in-house built column size with ∅=1.5 mm was prepared, and 3 mg of Sim-MIP particles was packed in the column. During the sensing process, 90% of the simazine loaded to the column was collected by elution. The reductive current of simazine was determined up to 1–10 μM. Solid phase extraction through the Sim-MIP column enabled simazine to be selectively detected from a mixed aqueous solution containing structural analogues in the range of 10–40 nM. Whether the concentration of simazine in tap water had reached environmentally restricted levels (10–40 nM) was determined within 1 hour using this system

Improvement of Accuracy in Flow Immunosensor System by Introduction of Poly-2-[3-(methacryloylamino)propylammonio]ethyl 3-aminopropyl Phosphate

In order to improve the accuracy of immunosensor systems, poly-2-[3-(methacryloylamino)propylammonio]ethyl 3-aminopropyl phosphate (poly-3MAm3AP), which includes both phosphorylcholine and amino groups, was synthesized and applied to the preparation of antibody-immobilized beads. Acting as an antibody-immobilizing material, poly-3MAm3AP is expected to significantly lower nonspecific adsorption due to the presence of the phosphorylcholine group and recognize large numbers of analytes due to the increase in antibody-immobilizing sites. The elimination of nonspecific adsorption was compared between the formation of a blocking layer on antibody-immobilized beads and the introduction of a material to combine antibody with beads. Determination with specific and nonspecific antibodies was then investigated for the estimation of signal-to-noise ratio. Signal intensities with superior signal-to-noise ratios were obtained when poly-3MAm3AP was introduced. This may be due to the increase in antibody-immobilizing sites and the extended space for antigen-antibody interaction resulting from the electrostatic repulsion of poly-3MAm3AP. Thus, the application of poly-3MAm3AP coatings to immunoassay beads was able to improve the accuracy of flow immunosensor systems

New Approach to a Practical Quartz Crystal Microbalance Sensor Utilizing an Inkjet Printing System

The present work demonstrates a valuable approach to developing quartz crystal microbalance (QCM) sensor units inexpensively for reliable determination of analytes. This QCM sensor unit is constructed by inkjet printing equipment utilizing background noise removal techniques. Inkjet printing equipment was chosen as an alternative to an injection pump in conventional flow-mode systems to facilitate the commercial applicability of these practical devices. The results demonstrate minimization of fluctuations from external influences, determination of antigen-antibody interactions in an inkjet deposition, and quantification of C-reactive protein in the range of 50–1000 ng∙mL−1. We thus demonstrate a marketable application of an inexpensive and easily available QCM sensor system