An innovative and environmentally friendly method for the synthesis of size-controlled silver nanoparticles (AgNPs) is presented. Pectin-stabilized AgNPs were synthesized in a plasma-reaction system in which pulse-modulated radio-frequency atmospheric-pressure glow discharge (pm-rf-APGD) was operated in contact with a flowing liquid electrode. The use of pm-rf-APGD allows for better control of the size of AgNPs and their stability and monodispersity. AgNPs synthesized under defined operating conditions exhibited average sizes of 41.62 ± 12.08 nm and 10.38 ± 4.56 nm, as determined by dynamic light scattering and transmission electron microscopy (TEM), respectively. Energy-dispersive X-ray spectroscopy (EDS) confirmed that the nanoparticles were composed of metallic Ag. Furthermore, the ξ-potential of the AgNPs was shown to be −43.11 ± 0.96 mV, which will facilitate their application in biological systems. Between 70% and 90% of the cancerous cells of the human melanoma Hs 294T cell line underwent necrosis following treatment with the synthesized AgNPs. Furthermore, optical emission spectrometry (OES) identified reactive species, such as NO, NH, N₂, O, and H, as pm-rf-APGD produced compounds that may be involved in the reduction of the Ag(I) ions.

Microwave treatment can reduce the time of selected syntheses, for instance of gold nanoparticles (AuNPs), from several hours to a few minutes. We propose a microfluidic structure for enhancing the rate of chemical reactions using microwave energy. This reactor is designed to control microwave energy with much higher accuracy than in standard devices. Thanks to this, the influence of microwave irradiation on the rate of chemical reactions can be investigated. The reactor consists of a transmission line surrounded by ground metallization. In order to deliver microwave energy to the fluid under test efficiently, matching networks are used and optimized by means of numerical methods. The monolithic device is fabricated in the low temperature co-fired ceramics (LTCC) technology. This material exhibits excellent microwave performance and is resistant to many chemical substances as well as high temperatures. Fabrication of the devices is described in detail. Measurements of microwave parameters are performed and differences between simulation and experiment results are discussed. Finally, the usefulness of the proposed device is proved in exemplary synthesis.

Microwave treatment can reduce the time of selected syntheses, for instance of the gold nanoparticles, from several hours to the few minutes. We propose microfluidic structure for enhancing rate of chemical reactions using microwave power. This reactor is designed to control microwave power with much higher accuracy than in standard devices. Thanks to this the influence of microwave irradiation on the rate of chemical reactions can be investigated. The reactor consists of transmission line surrounded by the ground metallization. In order to efficient deliver microwave power to the fluid matching networks are optimized using numerical methods. The monolithic device is fabricated in the Low Temperature Co-fired Ceramics (LTCC) technology. This material exhibits excellent microwave performance, and is resistant to many chemical substances as well as high temperature. Fabrication of the devices is described in details. Measurements of microwave parameters are performed and differences between simulation and experiment results are discussed.

In this article, we present a development of atmospheric pressure plasma jets (APPJs) for modification of liquid solutions. APPJs were fabricated in low temperature cofired ceramics (LTCC) technology. During the measurements, plasma jets worked under various flowing gases, which can be used to produce plasma activated water. In addition, owing to the plasma treatment, it was possible to decrease the time of a synthesis of gold nanoparticles (AuNPs) without the use of additional hazardous reagents. The mechanism of gold nanoparticles formation in cold nitrogen plasma is also presented.

Purpose: This paper aims to focus on the application of low temperature co-fired ceramic (LTCC) technology in the fabrication of a microfluidic module with integrated microwave components. The design, technology and performance of such an LTCC-based module is investigated. The rapid heating of liquid samples on a microliter scale is shown to be possible with the use of microwaves. Design/methodology/approach: The developed microwave-microfluidic module was fabricated using well-known LTCC technology. The finite element method was used to design the geometry of the microwave circuit. Various numerical simulations for different liquids were performed. Finally, the performance of the real LTCC-based microwave-microfluidic module was examined experimentally. Findings: LTCC materials and technology can be used in the fabrication of microfluidic modules which use microwaves in the heating of the liquid sample. LTCC technology permits the fabrication of matching circuits with appropriate geometry, whereas microwave power can be used to heat up the liquid samples on a microliter scale. Research limitations/implications: The main limitation of the presented work is found to be in conjunction with LTCC technology. The dimensions and shape of the deposited conductors (e.g. microstrip line, matching circuit) depend on the screen-printing process. A line with resolution lower than 75 µm with well-defined edges is difficult to obtain. This can have an effect on the high-frequency properties of the LTCC modules. Practical implications: The presented LTCC-based microfluidic module with integrated microwave circuits provides an opportunity for the further development of various micro-total analysis systems or lab-on-chips in which the rapid heating of liquid samples in low volumes is needed (e.g. miniature real-time polymerase chain reaction thermocycler). Originality/value: Examples of the application of LTCC technology in the fabrication of microwave circuits and microfluidic systems can be found in the available literature. However, the LTCC-based module which combines microwave and microfluidic components has yet to have been reported. The preliminary work on the design, fabrication and properties of the LTCC microfluidic module with integrated microwave components is presented in this paper.

Purpose: The purpose of this paper is a presentation of a miniature vertical dielectric barrier discharge (DBD) plasma generators. The presented devices, with sub- and superstrate, were made using low temperature co-fired ceramics (LTCC). Such construction allowed to measure discharge spectra and device temperature easily. Design/methodology/approach: The generators were made in the Du Pont 951 system with silver vertical metallizations and PdAg contacts. The devices had electrodes with different width and height. Also, the distance between them could be established. They were placed on substrate with buried temperature sensor and covered with a ceramic lid. The lid had opening to measure emitted light. Different configurations of vertical DBD were tested. Findings: Geometry of vertical metallizations influences on spectra, as well as distance between them. Signal-to-noise ratio had a maximum for certain generators and can be measured by the intensity of highest peak. Research limitations/implications: Height of vertical metallizations is limited by the difference in shrinkage of LTCC tape and via paste. Parameters of temperature sensors vary between measurements, according to rapid changes of temperature and presence of strong electric field. Practical implications: The generators can be used for creating discharge for optical emission spectrometry. It is a convenient method to determine the amount of selected gas compounds. Originality/value: This paper shows fabrication and performance of the novel vertical DBD generators with ceramic additions for convenient spectra measurement and monitoring temperature of the device during work.