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Within the last decades, a growing number of miniaturized solutions for biological and chemical analysis processes have been developed by scaling these analyses down to a lab-on-a-chip (LoC) level, thanks to sensitive and rapid testing abilities of LoCs. In parallel to that, a significant need for high-throughput and cost-efficient production of LoC components arises. Our roll-to-roll (R2R) pilot-line for imprinting micro- and nano- structures onto polymers in various designs provides high-throughput manufacturing solutions for polymer based flexible LoC components. The structure imprinting (

The UV-nanoimprint lithography(UV-NIL) fabrication of a novel network of micron-sized channels, forming an open channel microfluidic system is described. Details about the complete manufacturing process, from mastering to fabrication in small batches and in high throughput with up to 1200 micro titer plates per hour is presented. Deep insight into the evaluation of a suitable UV-curable material, mr-UVCur26SF is given, presenting cytotoxic evaluation, cell compatibility tests and finally a neuronal assay. The results indicate how the given pattern, in combination with the resist, paves the way to faster, cheaper, and more reliable drug screening. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement NO. 646260. The research was also partially supported by NextGenMicrofluidics project under HORIZON2020 with grant agreement no 862092.

Roll-to-roll UV nanoimprint lithography has superior advantages for high-throughput manufacturing of micro- or nano-structures on flexible polymer foils with various geometries and configurations. Our pilot line provides large-scale structure imprinting for cost-effective polymer biochips (4500 biochips/hour), enabling rapid and multiplexed detections. A complete high-volume process chain of the technology for producing structures like μ-sized, triangular optical out-couplers or capillary channels (width: from 1 μm to 2 mm, height: from 200 nm up to 100 μm) to obtain biochips (width: 25 mm, length: 75 mm, height: 100 μm to 1.5 mm) was described. The imprinting process was performed with custom-developed resins on polymer foils with resin thicknesses ranging between 125–190 μm. The produced chips were tested in a commercial point-of-care diagnostic system for multiplexed DNA analysis of methicillin resistant Staphylococcus aureus (e.g., mecA, mecC gene detections). Specific target DNA capturing was based on hybridisation between surface bound DNA probes and biotinylated targets from the sample. The immobilised biotinylated targets subsequently bind streptavidin–horseradish peroxidase conjugates, which in turn generate light upon incubation with a chemiluminescent substrate. To enhance the light out-coupling thus to improve the system performance, optical structures were integrated into the design. The limits-of-detection of mecA (25 bp) for chips with and without structures were calculated as 0.06 and 0.07 μM, respectively. Further, foil-based chips with fluidic channels were DNA functionalised in our roll-to-roll micro-array spotter following the imprinting. This straightforward approach of sequential imprinting and multiplexed DNA functionalisation on a single foil was also realised for the first time. The corresponding foil-based chips were able to detect mecA gene DNA sequences down to a 0.25 μM concentration. This research was supported by R2R BIOFLUIDICS project (http://www.r2r-biofluidics.eu/) under Horizon 2020 European Union (EU) Research and Innovation Programme with grant agreement no 646260. The research was also partially supported by NextGenMicrofluidics project (https:// www. nextgenmicrofluidics.eu/) under HORIZON2020 with grant agreement no 862092. The authors cordially thank Gerburg Schider & Gerhard Mohr, Markus Postl, Paul Patter and Alexander Wheeldon (JOANNEUM RESEARCH – Materials, Weiz, Austria) for revising the manuscript, preparing all the chip and R2R pilot line illustrations, taking the photographs and providing technical support, respectively. The authors are also grateful to Christian Wolf and Johannes Götz (JOANNEUM RESEARCH – Materials, Weiz, Austria) for their supports in the fluidic design and R2R UV-NIL structuring, respectively. We further kindly thank Alba Simon Munoz and Robert Fay (SCIENION AG, Berlin, Germany) for providing the illustration of the R2R micro-spotting line. PT specially thanks Ege Ozgun (NANOTAM, Bilkent University, Ankara, Turkey) for critically reading the manuscript.

In this paper, we present a soil nutrient sensor based on the capillary electrophoresis chip technology. As a product intended for commercial use in soil nutrient analysis, we focused on the analysis of -NO3 and -SO4. The sensing core of the device is the microfluidic chip. The design of chip, adapted to the needs of a portable handheld device, hinders the flow of sample in the detection area - due to non-planarity of instalment or pressure differences - via a narrow injection channel. A known issue, is the injection discrepancies caused by chip-to-chip variances and overall ion strength, thus turning quantitative analysis into a challenge. We overcame this by adopting bromide as an internal standard. In order to discriminate bromide from ubiquitous chloride in soil samples we used polyvinylpyrrolidone (PVP) as a separation additive in our background electrolyte. An in-house algorithm was developed for the identification of the measurement peaks, consisting of a baseline smoothing and subtraction along with an optimized quantification of the area under the peaks and thus the ion concentration. For the detection of the ion concentration on-chip electrodes were utilized for a capacitively coupled conductivity measurement. Tests were performed with soil sample extractions from different regions and the results were cross-referenced with an ion chromatographer. The sensor’s response had to be corrected for different ions and it exhibited a second order polynomial response with an average absolute error of 5%.

A high throughput manufacturing process of microfluidic chips based on Roll-to-Roll imprinting is presented. With this procedure, microfluidic patterns can be produced on large area polymer substrates. The subsequent steps of inlet drilling, bonding and electrode printing are set-up on large area processes, too. Overall, this strategy allows highly parallelized processing of large numbers of chips—all costly steps of individual chip handling are avoided. The chips were used for the characterization of inorganic ions for soil nutrient analysis.

In microchip capillary electrophoresis most frequently electrokinetic sample injection is utilized, which does not allow pressure driven sample handling and is sensitive for pressure drops due to different reservoir levels. For efficient field tests a multitude of samples have to be processed with the least amount of external equipment. We present the use of a hydrogel plug to separate the sample from clean buffer to enable independent sample change and buffer refreshment. In-situ polymerization of the gel does away with complex membrane fabrication techniques. The sample is electrokinetically injected through the gel and subsequently separated by a voltage between the second gel inlet and the buffer outlet. By blocking of disturbing flows by the gel barrier a well-defined ion plug is obtained. After each experiment, the sample and the separation channel can be flushed independently, allowing for a continuous operation mode in order to process multiple samples.

With the Covid-19-based global pandemic that started in the beginning of 2020, the vital importance of accelerated, reliable and affordable virus testing systems has once again become clearer. Besides, we all learned very well that the disposable biochips, to be used in these in vitro diagnostic (IVD) testing systems, supposed to be produced in large amounts in a very short time to be widely available for the use of humanity to save more and more lives. That is why; roll-to-roll (R2R) polymer structuring manners offer such large quantities for the production of in vitro biochips. Our technology, based on R2R UV nanoimprint lithography (UV-NIL), has superior features. Via our pilot line, robust 7500 biochip components per 100 meter of a flexible, polymer foil coated with a UV curable photo-resin (i.e., parts with capillary fluidic channels or optical structures for IVDs) can be generated. This study shows an example of a prototype of a R2R UV-NIL generated chip: a foil, capillary flow-based IVD biochip for multiplexed DNA detection purposes (i.e., a Lab-on-a-Foil device). The biochip performance was further increased dramatically by integrating UV-NIL produced retro-reflective microstructures, which reflects the light back, to its design to enhance optical signal detection in a commercial IVD device, detecting DNA on a chemiluminescent-reaction basis. Graphic Abstract

R2R-UV-nanoimprinting sets new benchmarks for the fabrication of miniaturized, low-cost and low-weight freeform micro-optical elements applicable in lighting, display, medical diagnostics, etc. We demonstrate the related process chain, combining optical design, direct laser lithography, step&repeat imprinting and R2R reproduction.