Development of a sticker sealed microfluidic device for in situ analytical measurements using synchrotron radiation

Abstract

Shedding synchrotron light on microfluidic systems, exploring several contrasts in situ operando at the nanoscale, like X-ray fluorescence, diffraction, luminescence, and absorption, has the potential to reveal new properties and functionalities of materials across diverse areas, such as green energy, photonics, and nanomedicine. In this work, we present the micro-fabrication and characterization of a multifunctional polyester/glass sealed microfluidic device well-suited to combine with analytical X-ray techniques. The device consists of smooth microchannels patterned on glass, where three gold electrodes are deposited into the channels to serve in situ electrochemistry analysis or standard electrical measurements. It has been efficiently sealed through an ultraviolet-sensitive sticker-like layer based on a polyester film, and The burst pressure determined by pumping water through the microchannel(up to 0.22 MPa). Overall, the device has demonstrated exquisite chemical resistance to organic solvents, and its efficiency in the presence of biological samples (proteins) is remarkable. The device potentialities, and its high transparency to X-rays, have been demonstrated by taking advantage of the X-ray nanoprobe Carnaúba/Sirius/LNLS, by obtaining 2D X-ray nanofluorescence maps on the microchannel filled with water and after an electrochemical nucleation reaction. To wrap up, the microfluidic device characterized here has the potential to be employed in standard laboratory experiments as well as in situ and in vivo analytical experiments using a wide electromagnetic window, from infrared to X-rays, which could serve experiments in many branches of science.

Development of electrochemical cells for spatially resolved analysis using a multi-technique approach: from conventional experiments to X-ray nanoprobe beamlines

“…Hereafter, we shall refer to these cells as spectroelectrochemical cells (SECs) for brevity, although they can be utilized in photoelectrochemistry too. The purpose-built cells designed especially for the nanoprobe beamline were based on previous models (one used for several in situ techniques in our group, [67] and a microfluidic model designed for the Carnaúba beamline [68] after some improvements).…”

“…[73][74][75][76] For this reason, we also developed a microfluidic SEC for X-ray analysis at SIRIUS, whose fabrication procedure was described in detail elsewhere. [68] Briefly, the device consists of microchannels, and electrodes patterned by photolithography, sealed with a 12 μm thick layer of polyester film, which is highly transparent to X-rays above 7 keV (figure 5.A). This remarkably simple setup allows experiments using in situ X-ray diffraction (reflection mode) and absorption experiments, exploiting the fluorescence contrast.…”

Development of Electrochemical Cells and Their Application for Spatially Resolved Analysis Using a Multitechnique Approach: From Conventional Experiments to X-Ray Nanoprobe Beamlines

“…This remarkably simple setup allows experiments using in situ X-ray diffraction (reflection mode) and absorption experiments, exploiting the fluorescence contrast. 47 This cell is an improved version of a previous setup whose fabrication procedure was described in detail elsewhere. 42 It is important to note that the interaction with the X-rays is determined by factors such as the composition of the working electrode, the design of the solution compartment, and the polymer utilized for cell encapsulation.…”

“…Microfluidic cells have attracted the interest of the synchrotron community due to their reduced size, weight, high throughput, and compatibility with both in situ and in vivo experiments. , The device consists of microchannels, and electrodes patterned by photolithography, sealed with a 12 μm-thick layer of polyester film, which is highly transparent to X-rays above 7 keV. This remarkably simple setup allows experiments using in situ X-ray diffraction (reflection mode) and absorption experiments, exploiting the fluorescence contrast . This cell is an improved version of a previous setup whose fabrication procedure was described in detail elsewhere .…”