The clinical applications of sensing tools (i.e., biosensors) for the monitoring of physiologically important analytes are very common. Nowadays, the biosensors are being increasingly used to detect physiologically important analytes in real biological samples (i.e., blood, plasma, urine, and saliva). This review focuses on biosensors that can be applied to continuous, time-resolved measurements with fluorescence. The material presents the fluorescent biosensors for the detection of neurotransmitters, hormones, and other human metabolites as glucose, lactate or uric acid. The construction of microfluidic devices based on fluorescence uses a variety of materials, fluorescent dyes, types of detectors, excitation sources, optical filters, and geometrical systems. Due to their small size, these devices can perform a full analysis. Microfluidics-based technologies have shown promising applications in several of the main laboratory techniques, including blood chemistries, immunoassays, nucleic-acid amplification tests. Of the all technologies that are used to manufacture microfluidic systems, the LTCC technique seems to be an interesting alternative. It allows easy integration of electronic and microfluidic components on a single ceramic substrate. Moreover, the LTCC material is biologically and chemically inert, and is resistant to high temperature and pressure. The combination of all these features makes the LTCC technology particularly useful for implementation of fluorescence-based detection in the ceramic microfluidic systems.
Purpose: The purpose of this paper is to review possibilities of implementing ceramic additive manufacturing (AM) into electronic device production, which can enable great new possibilities. Design/methodology/approach: A short introduction into additive techniques is included, as well as primary characterization of structuring capabilities, dielectric performance and applicability in the electronic manufacturing process. Findings: Ceramic stereolithography (SLA) is suitable for microchannel manufacturing, even using a relatively inexpensive system. This method is suitable for implementation into the electronic manufacturing process; however, a search for better materials is desired, especially for improved dielectric parameters, lowered sintering temperature and decreased porosity. Practical implications: Relatively inexpensive ceramic SLA, which is now available, could make ceramic electronics, currently restricted to specific applications, more available. Originality/value: Ceramic AM is in the beginning phase of implementation in electronic technology, and only a few reports are currently available, the most significant of which is mentioned in this paper.
One of the major issues in microfluidic biosensors is biolayer deposition. Typical manufacturing processes, such as firing of ceramics and anodic bonding of silicon and glass, involve exposure to high temperatures, which any biomaterial is very vulnerable to. Therefore, current methods are based on deposition from liquid, for example, chemical bath deposition (CBD) and electrodeposition (ED). However, such approaches are not suitable for many biomaterials. This problem was partially resolved by introduction of ceramic–polymer bonding using plasma treatment. This method introduces an approximately 15-min-long window for biomodification between plasma activation and sealing the system with a polymer cap. Unfortunately, some biochemical processes are rather slow, and this time is not sufficient for the proper attachment of a biomaterial to the surface. Therefore, a novel method, based on plasma activation after biomodification, is introduced. Crucially, the discharge occurs selectively; otherwise, it would etch the biomaterial. Difficulties in manufacturing ceramic biosensors could be overcome by selective surface modification using plasma treatment and bonding to polymer. The area of plasma modification was investigated through contact-angle measurements and Fourier-transform infrared (FTIR) analyses. A sample structure was manufactured in order to prove the concept. The results show that the method is viable.
21 January 2016 in IOP Conference Series: Materials Science and Engineering
This study was focused on how to improve the gas sensing properties of resistive gas sensors based on zinc oxide to dimethyl sulfide (DMS). The aim of this research was to investigate possible ways of improvement detection of dimethyl sulfide, such as volume doping with synthesized gold nanoparticles or applying sepiolite passive filter. The addition of noble metal into the gas sensing layer is a widely known method of increasing gas sensor response. Sepiolite is a clay mineral with highly porous structure consisting of nanotubes few micrometers long and water absorption abilities. In this work thick-film resistive gas sensors based on zinc oxide were made (pure ZnO, modified by gold nanoparticles, with the addition of filter) and tested for low concentration (2 ppm) of dimethyl sulfide. The sensitivities to DMS of developed sensors were compared. Attention was paid to the analysis of the impact of high humidity (90% RH) on the sensor time response.
The Low Temperature Cofired Ceramic (LTCC) technology has proven to be highly suitable for 3D microstructures manufacturing in electronic devices due to its excellent electrical and mechanical properties. In this paper, a novel idea of implementing the LTCC structures into high-energy particle detectors technology is proposed. It can be applied in High Energy Physics (HEP) laboratories, where such sophisticated sensors are constantly exposed to particles of the TeV energy range for many years. The most advanced applications of the concept are based on dedicated gas amplifier systems coupled with readout microstructures. Typically, the readout microstructures are made in the Printed Circuit Boards (PCB) technology and processed in a sophisticated and patent-protected way. This article presents the manufacturing process and parameters of the novel microstructures made in the LTCC technology. The structures were implemented into the high-energy particle detector, and the first results are presented.
11 November 2020 in Periodica Polytechnica Electrical Engineering and Computer Science
In this work a fluorescent microfluidic sensor is developed, manufactured and characterized through additive manufacturing technique, using transparent photopolymer. A technology widely known as 3D printing is very suitable for tailor-made microfluidic chips, as it allows for rapid manufacturing. Optical structures can be developed using transparent materials, and this work describes a technique for increasing light transmission through such structure. A complete, inexpensive electronic device is described, containing microfluidic chip, light source, photodetector, microcontroller, communication interface and a multifunctional package with embedded connectors. Performed analyses show that performed surface modification significantly improves light transmission through structure, the material does not show autofluorescence, and whole device is suitable for fluorescence measurements.