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Acute kidney injury (AKI) is a known risk factor for chronic kidney disease (CKD). The mechanisms for AKI-CKD transition may involve failed tubule repair and progressive interstitial fibrosis but are incompletely understood. Which events lead to failed tubule repair? Can injury spread over time? And are these processes steered by myofibroblasts and fibrotic tissue remodeling?Here, we combined serial intravital 2-photon microscopy and a novel model of partial ischemia-reperfusion injury (partial IRI), which allowed us to investigate injured tissue alongside uninjured tissue in the same kidney and over time. Thus, we occluded only one branch of the left renal artery for 21 min, rendering half the kidney ischemic. We then tracked tubule necrosis and remodeling alongside myofibroblast dynamics for up to 3 weeks. Necrotic cell death was detected by in vivo propidium iodide staining. PDGFRβ-CreERT2-Salsa6F mice (N=5) identified main myofibroblast precursor cells, by tdTomato-expression. Myofibroblast-differentiation was confirmed by ex vivo αSMA staining. Proximal tubule (PT) function was assessed by in vivo uptake of fluorescent albumin.Necrotic cell death was solely detectable upon reperfusion. Border areas in between post-ischemic and non-ischemic tissue presented severely necrotic PTs alongside uninjured PTs. From 1 day after partial IRI, we observed formation of granular casts in the lumen of necrotic tubules, which 1-2 days later also appeared in initially non-necrotic PTs downstream. Tubule necrosis and granular cast accumulation preceded thinned epithelium that lacked albumin endocytosis (day 3-7) and recruitment of myofibroblasts (peaking D4-10). Of note, non-necrotic tubules, without granular cast accumulation, didn’t remodel nor recruit myofibroblasts.Among all remodeling tubule segments, 24% turned atrophic. Importantly, preceding necrotic cell death was higher in atrophic than in recovering tubules (55±13% vs. 39±18% necrotic cells/total segment cell number, (mean±SD), p Novo Nordisk Foundation, Augustinus Foundation, Aarhus University Research Foundation (AUFF) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Acute kidney injury (AKI) is an important risk factor for chronic kidney disease (CKD), but the underlying mechanisms of failed tubule repair and AKI-CKD-transition are incompletely understood. In this study, we aimed for dynamic tracking of tubule injury and remodeling to understand if focal injury upon AKI may spread over time. Here we present a novel model of AKI, in which we rendered only half of the kidney ischemic. Using serial intravital 2-photon microscopy and genetic identification of cycling cells, we tracked dynamic tissue remodeling in post- and non-ischemic kidney regions simultaneously and over 3 weeks. Spatial and temporal analysis of cycling cells relative to initial necrotic cell death, demonstrated pronounced injury propagation and expansion into previously uninjured tissue regions, which predicted tubule atrophy with epithelial VCAM-1 expression. In summary, our longitudinal analysis of tubule injury, remodeling, and fate, provided important novel insights into AKI pathology.

A reversible switchable on-demand UV-triggered drug delivery system (DDS) based on interpenetrating polymer networks (IPNs) with silicone as the host polymer and spiropyran (SP)-functionalized guest polymer is designed and demonstrated. The photo-responsive IPNs provide a new triggered drug delivery concept as they exploit the change in intermolecular interactions (work of adhesion) among the drug, matrix, and solvent when the incorporated hydrophobic SP moieties transform into the hydrophilic merocyanine form upon light irradiation without degradation and disruption of the DDS. The change in how the copolymer composition (hydrophilicity and content) and the lipophilicity of the drug (log P) affect the release profile was investigated. A thermodynamic model, based on Hansen solubility parameters, was developed to design and optimize the polymer composition of the IPNs to obtain the most efficient light-triggered drug release and suppression of the premature release. The developed IPNs showed excellent result for dopamine, l-dopa, and prednisone with around 90-95% light-triggered release. The model was applied to study the release behavior of drugs with different log P and to estimate if the light-induced hydrophobic-to-hydrophilic switch can overcome the work of adhesion between polymers and drugs and hence the desorption and release of the drugs. To the best of our knowledge, this is the first time that work of adhesion is used for this aim. Comparing the result obtained from the model and experiment shows that the model is useful for evaluating and estimating the release behavior of specific drugs merocyanine, IPN, DDS, and spiropyran.

One of the challenges for metasurface research is upscaling. The conventional methods for fabrication of metasurfaces, such as electron-beam or focused ion beam lithography, are not scalable. The use of ultraviolet steppers or nanoimprinting still requires large-size masks or stamps, which are costly and challenging in further handling. This work demonstrates a cost-effective and lithography-free method for printing optical metasurfaces. It is based on resonant absorption of laser light in an optical cavity formed by a multilayer structure of ultrathin metal and dielectric coatings. A nearly perfect light absorption is obtained via interferometric control of absorption and operating around a critical coupling condition. Controlled by the laser power, the surface undergoes a structural transition from random, semiperiodic, and periodic to amorphous patterns with nanoscale precision. The reliability, upscaling, and subwavelength resolution of this approach are demonstrated by realizing metasurfaces for structural colors, optical holograms, and diffractive optical elements.

Flow cytometry (FC) is a pivotal tool for studying the physical and chemical properties of particles. State-of-the-art FC systems are highly advanced, yet they are expensive, bulky, and require high sample volume, qualified operators, and periodic maintenance. The manipulation of particles suspended in viscoelastic fluids has received increasing attention, especially for miniaturized flow cytometry technologies. This study presents a miniaturized optical capillary FC device using the viscoelastic focusing technique. A straight, one inlet/outlet microcapillary device is precisely aligned to a fiber-coupled laser source and detectors. Forward scattered, side scattered, and fluorescently emitted light signals are collected and analyzed in a real-time environment. The developed platform fits onto an inverted microscope stage enabling real-time microscopy imaging of the particles of interest together with the flow cytometry analysis. We achieved stable viscoelastic focusing and performed FC measurements for rigid polystyrene beads (diameters: 2 - 15 μm), non-spherical human erythrocytes, and canonical shape metaphase human chromosomes. We performed cytometry measurements with a throughput of 100 events/s yielding a coefficient of variation of 2%. This newly developed FC device is a versatile tool and can be operated with any inverted microscope to get the mutual benefits of optical and imaging FC measurements. Furthermore, it is possible to extend these benefits by adding more back-end tools, such as optical trapping and Raman spectroscopy.

A compact microfluidic flow cytometer is demonstrated, comprising viscoelastic flow focusing in fused silica capillaries and a fiber optical interface. Viscoelastic flow focusing enables simple device design and operation with a single-inlet/outlet fluidic configuration. Fused silica capillaries with different inner diameters are effortlessly interchanged to eliminate blockage ratio limitations and enable single-train particle focusing for a wide range of particle sizes and geometries. The compact system is mounted on an inverted microscope for easy integration with optical imaging and other optofluidic modalities, such as optical trapping and particle sorting. A real-time cytometric analysis of three channels, forward scattering, side scattering, and fluorescence detection, is performed on LABVIEW. A throughput of 3500 events s(-1) is performed on particles of sizes ranging from 2 to 20 mu m, using capillaries of different inner diameters ranging from 30 to 75 mu m. The outer diameter of all capillaries is identical to the cladding diameter of the applied optical fibers. This enables easy exchange and precise optical alignment of fibers and capillaries on a microfabricated jig. The performance of the microfluidic flow cytometer is benchmarked using polystyrene calibration beads, poly(lactic-co-glycolic acid) particles, erythrocytes, THP-1 leukemic monocytes, and human metaphase chromosomes.

Blood plasma evaluation has high significance in clinical diagnostics. Current schemes involve the preparation of blood plasma by centrifugation of whole blood followed by electrochemical or spectroscopic analysis. However, centrifugation is often too time-consuming for application in clinical emergency and point-of-care settings. We propose to combine microfluidic, instantaneous plasma fractionation with localized spectroscopic methods for in-line analysis. As an example, we present confocal Raman spectroscopy in fractionated plasma domains at two different Raman excitation wavelengths. Resonance Raman spectroscopy with laser excitation at 408 nm allows the specific detection of free hemoglobin in blood plasma at concentrations above 22 mg dl-1 (level of detection). Consequently, we are able to accurately resolve the range of clinical relevance regarding hemolysis. At near-infrared excitation (785 nm) we furthermore demonstrate the acquisition of characteristic Raman spectra of fractionated blood plasma in the microfluidic setting. These spectra can serve as starting point for a multi-parameter regression analysis to quantify a set of blood plasma parameters from a single Raman spectrum. The combined microfluidics and Raman spectroscopy method is non-destructive and has a whole blood consumption of less than 100 μl per hour. It thus allows for continuous in-line blood plasma monitoring.

In the pig farming industrial sector, innovation is a crucial factor in maintaining competitiveness. On the research side, there exists a large body of models and decision analysis tools that too often do not reach the end-user. In this chapter, we propose a software-as-a-service based on a cloud-based Decision Support System architecture that should overcome the main adoption barriers spotted in the literature. The service proposed takes advantage of existing herd management models feed with historical farm data and economic parameters recorded by the most popular farm management software used by pig companies. The approach includes a sow farm model and offers a set of analytic tools to help farmers in making better strategic, tactical and operational decisions based on their own data. This chapter highlights the advantages of optimization and simulation models hosted in a cloud computing platform to deliver a service of knowledge discovering and data analytics to sow farms. The success in adoption depends on the added value and usability through software integration with current management tools used by pig producers. Preliminary results show that the proposed service helps pig managers to make better supervision of sows and to obtain the competitive advantages of using complex mathematical models in a practical, flexible and transparent way.

Plasmonic color metasurfaces enable high resolution, ink-free color decoration and sensing devices. This work presents a full solution from design of plasmonic color elements suitable for master origination by 248 nm Deep Ultraviolet (DUV) lithography to production grade manufacture of plasmonic color metasurfaces on plastic substrates. Design of hybrid aluminum disk-hole structures with hybridized multiple resonances, which are controlled by the disk-hole distance, enables plasmonic color generation across the visible spectrum with larger sized nanostructures, above 160 nm. Such larger structures can be defined by 248 nm DUV lithography as a cost-efficient and high throughput alternative to, e.g., electron beam lithography.

The advent of resonant dielectric nanomaterials has provided a new path for concentrating and manipulating light on the nanoscale. Such high-refractive-index materials support a diverse set of low-loss optical resonances, including Mie resonances, anapole states, and bound states in the continuum. Through these resonances, high-refractive-index materials can be used to engineer the optical near field, both inside and outside the nanostructures, which opens up new opportunities for Raman spectroscopy. In this review, we discuss the impact of high-refractive-index nano-optics on Raman spectroscopy. In particular, we consider the intrinsic Raman enhancement produced by different dielectric resonances and their theoretical description. Using the optical reciprocity theorem, we derive an expression which links the Raman enhancement to the enhancement of the stored electric energy. We also address recent results on surface-enhanced Raman spectroscopy based on high-refractive-index dielectric materials along with applications in stimulated Raman scattering and nanothermometry. Finally, we discuss the potential of Raman spectroscopy as a tool for detecting the optical near-fields produced by dielectric resonances, complementing reflection and transmission measurements.

Disclosed is a method for self-organization of a nanostructure, comprising the steps of, providing a narrow-band light source having a center wavelength; providing a film on a substrate, said thin film having a film thickness, said film thickness being in the range from 0.9 to 1.1 times a Fabry Perot resonance condition thickness for said center wavelength; and irradiating said film, the irradiating comprises using said narrow-band light source to induce self-organization of said film, thereby obtaining nanostructures. A product comprising a substrate and nanostructures produced by said method is further disclosed.

Viscoelastic flow-based particle manipulation techniques enable bio-particle focusing, separation, and enrichment by precisely tuning the rheological parameters, flow conditions, and microchannel geometry. In this study, we fabricated a PDMS-based single inlet/outlet microchannel to separate bio-particles by their size ranging from 1-10 μm. Flow conditions and rheological properties are optimized using 2 μm and 4 μm Polystyrene beads to reach the best particle separation condition. We demonstrated the size-based separation of human chromosomes by separating 1-2 μm size small chromosomes from 8-10 μm size large chromosomes. Thanks to its miniaturized size and simplicity, the isolation chip and unique viscoelastic separation method have great potential to be used as a future pioneering tool for genetic applications to study chromosome abnormalities such as fragile-X and trisomy.

The replacement of plastic with eco-friendly and biodegradable materials is one of the most stringent environmental challenges. In this respect, cellulose stands out as a biodegradable polymer. However, a significant challenge is to obtain biodegradable materials for high-end photonics that are robust in humid environments. Here, we demonstrate the fabrication of high-quality micro- and nanoscale photonic and plasmonic structures via replica molding using pure cellulose and a blended version with nonedible agro-wastes. Both materials are biodegradable in soil and seawater according to the ISO 17556 standard. The pure cellulose films are transparent in the vis–NIR spectrum, having a refractive index similar to glass. The microstructured photonic crystals show high-quality diffractive properties that are maintained under extended exposure to water. Nanostructuring the cellulose transforms it to a biodegradable metasurface manifesting bright structural colors. A subsequent deposition of Ag endowed the metasurface with plasmonic properties used to produce plasmonic colors and for surface-enhanced Raman scattering.

The ongoing effort to implement compact and cheap optical systems is the main driving force for the recent flourishing research in the field of optical metalenses. Metalenses are a type of metasurface, used for focusing and imaging applications, and are implemented based on the nanopatterning of an optical surface. The challenge faced by metalens research is to reach high levels of performance using simple fabrication methods suitable for mass production. In this paper, we present a Huygens nanoantenna-based metalens, designed for outdoor photographic/surveillance applications in the near infrared. We show that good imaging quality can be obtained over a field of view as large as ±15°. This first successful implementation of metalenses for outdoor imaging applications is expected to provide insight and inspiration for future metalens imaging applications.

We present a method of optimizing the operating spectral range of a metalens. This is of importance for practical applications, and as a metric for comparing the performance of different metalens designs.

Plasmonic color generation from metal nanostructures has attracted intensive attention because of their excellence in achieving high spatial resolution, strong color contrast, and long‐term durability. The limited area of plasmonic patterns anchored on substrates and produced by current top‐down methods, however, severely restricts the advanced developments and potential applications in structural color display. Herein a robust method for realizing the laser printing of plasmonic colors inside transparent gold nanodisk‐embedded poly(dimethylsiloxane) matrices is presented. It is found that various colors can not only be easily generated by embedding gold nanodisks of different sizes, but also finely varied by adjusting the laser pulse intensity during printing. It is further demonstrated that multiple color layers can be laser‐printed at different depths. Stereoscopic images in the 3D matrices are laser‐printed with sizes as large as 12 × 15 mm2 and a resolution of 4600 dots per inch.

This thesis seeks to investigate how Psalm 139, and biblical texts in general, can be interpreted to facilitate a meaningful reading by bereaved parents after the early loss of a child. By using in-depth interviews with bereaved parents, this study emphasises the reader’s perspective in its exegesis to produce a responsible, contemporary interpretation. I applied insights on the existential challenges of bereaved parents to a reader-oriented exegetical approach to Psalm 139, imagining a hypothetical reader’s creative engagement with the biblical text. To investigate the merit of this approach, the resulting interpretation was then compared to findings from interviews conducted with bereaved parents about their experiences of reading the psalm. This study finds that the individual experience of the reader is hugely influential in the creative process of interpretation. Depending on the reader’s past life and personal convictions, Psalm 139 can be immensely comforting or disconcerting. I conclude that the reader-oriented approach to exegesis is a valuable tool for any biblical scholar and minister, as it can unearth a wealth of relevant, contemporary interpretations inaccessible to the historical approach to exegesis. This thesis contends that scholarly biblical studies, homiletics and pastoral would all benefit greatly from an increased focus on the contemporary reader’s perspective.

Optical materials with a high refractive index enable effective manipulation of light at the nanoscale through strong light confinement. However, the optical near field, which is mainly confined inside such high-index nanostructures, is difficult to probe with existing measurement techniques. Here, we exploit the connection between Raman scattering and the stored electric energy to detect resonance-induced near-field enhancements in silicon nanostructures. We introduce a Raman setup with a wavelength-tunable laser, which allows us to tune the Raman excitation wavelength and thereby identify Fabry-Perot and Mie type resonances in silicon thin films and nanodisk arrays, respectively. We measure the optical near-field enhancement by comparing the Raman response on and off resonance. Our results show that tunable-excitation Raman spectroscopy can be used as a complimentary far-field technique to reflection measurements for nanoscale characterization and quality control. As proof-of-principle for the latter, we demonstrate that Raman spectroscopy captures fabrication imperfections in the silicon nanodisk arrays, enabling an all-optical quality control of metasurfaces.

Hemolysis is the rupture of red blood cells and constitutes the most common reason for unsuitable blood samples in the clinic. To detect hemolysis, one has to separate the hemoglobin in blood plasma from that in red blood cells. However, current methods entail centrifugation for cell-plasma separation, which is complex, time-consuming, and not easy to integrate into point-of-care (PoC) systems. Here, we demonstrate an optofluidic sensor composed of nanofilters on an optical waveguide, which enables evanescent-wave absorption measurement of hemoglobin in plasma with the capability of real-time inline detection on whole blood without extra sample preparation like centrifugation. Long-term testing with inline integration in a modified, commercial blood gas analyzer shows high reliability and repeatability of the measurements even with the presence of interference from bilirubin. We envision that the present work has large potential in improving diagnosis quality by enabling PoC hemolysis detection in blood gas analyzers and can also lend unique sensing capabilities to other applications dealing with complex turbid media.

Nucleotide incorporation by DNA polymerase forms the basis of DNA sequencing-by-synthesis. In current platforms, either the single-stranded DNA or the enzyme is immobilized on a solid surface to locate the incorporation of individual nucleotides in space and/or time. Solid-phase reactions may, however, hinder the polymerase activity. We demonstrate a device and a protocol for the enzymatic labeling of genomic DNA arranged in a dense array of single molecules without attaching the enzyme or the DNA to a surface. DNA molecules accumulate in a dense array of pits embedded within a nanoslit due to entropic trapping. We then perform ϕ29 polymerase extension from single-strand nicks created on the trapped molecules to incorporate fluorescent nucleotides into the DNA. The array of entropic traps can be loaded with λ-DNA molecules to more than 90% of capacity at a flow rate of 10 pL min-1. The final concentration can reach up to 100 μg mL-1, and the DNA is eluted from the array by increasing the flow rate. The device may be an important preparative module for carrying out enzymatic processing on DNA extracted from single-cells in a microfluidic chip.

Pyrolytic carbon microelectrodes (PCMEs) are a promising alternative to their conventional metallic counterparts for various applications. Thus, methods for the simple and inexpensive patterning of PCMEs are highly sought after. Here, we demonstrate the fabrication of PCMEs through the selective pyrolysis of SU-8 photoresist by irradiation with a low-power, 806 nm, continuous wave, semiconductor-diode laser. The SU-8 was modified by adding Pro-Jet 800NP (FujiFilm) in order to ensure absorbance in the 800 nm range. The SU-8 precursor with absorber was successfully converted into pyrolytic carbon upon laser irradiation, which was not possible without an absorber. We demonstrated that the local laser pyrolysis (LLP) process in an inert nitrogen atmosphere with higher laser power and lower scan speed resulted in higher electrical conductance. The maximum conductivity achieved for a laser-pyrolyzed line was 14.2 ± 3.3 S/cm, with a line width and thickness of 28.3 ± 2.9 µm and 6.0 ± 1.0 µm, respectively, while the narrowest conductive line was just 13.5 ± 0.4 µm wide and 4.9 ± 0.5 µm thick. The LLP process seemed to be self-limiting, as multiple repetitive laser scans did not alter the properties of the carbonized lines. The direct laser writing of adjacent lines with an insulating gap down to ≤5 µm was achieved. Finally, multiple lines were seamlessly joined and intersected, enabling the writing of more complex designs with branching electrodes and the porosity of the carbon lines could be controlled by the scan speed.

We demonstrate on-chip, differential DNA and RNA extraction from a single cell using a microfluidic chip and a two-stage lysis protocol. This method enables direct use of the whole extract, without additional washing steps, reducing sample loss. Using this method, the tumor driving pathway in individual cells from a colorectal cancer cell line was determined by applying a Bayesian computational pathway model to sequences obtained from the RNA fraction of a single cell and, the mutations driving the pathway were determined by analyzing sequences obtained from the DNA fraction of the same single cell. This combined functional and mutational pathway assessment of a single cell could be of significant value for dissecting cellular heterogeneity in tumors and analyzing single circulating tumor cells.

The ability to handle single, free molecules in lab-on-a-chip systems is key to the development of advanced biotechnologies. Entropic confinement offers passive control of polymers in nanofluidic systems by locally asserting a molecule's number of available conformation states through structured landscapes. Separately, a range of plasmonic configurations have demonstrated active manipulation of nano-objects by harnessing concentrated electric fields. The integration of these two independent techniques promises a range of sophisticated and complementary functions to handle, for example, DNA, but numerous difficulties, in particular, conflicting requirements of channel size, have prevented progress. Here, we show that metallic V-groove waveguides, embedded in fluidic nanoslits, form entropic potentials that trap and guide DNA molecules over well-defined routes while simultaneously promoting photothermal transport of DNA through the losses of plasmonic modes. The propulsive forces, assisted by in-coupling to propagating channel plasmon polaritons, extend along the V-grooves with a directed motion up to ≈0.5 μm·mW-1 away from the input beam and λ-DNA velocities reaching ≈0.2 μm·s-1·mW-1. The entropic trapping enables the V-grooves to be flexibly loaded and unloaded with DNA by variation of transverse fluid flow, a process that is selective to biopolymers versus fixed-shape objects and also allows the technique to address the challenges of nanoscale interaction volumes. Our self-aligning, light-driven actuator provides a convenient platform to filter, route, and manipulate individual molecules and may be realized wholly by wafer-scale fabrication suitable for parallelized investigation.

Aluminum plasmonics is emerging as a promising platform in particular for the ultraviolet-blue spectral band. We present the experimental results of propagating channel plasmon-polaritons (CPP) waves in aluminum coated V-shaped waveguides at the short visible wavelength regime. The V-grooves are fabricated by a process involving UV-photolithography, crystallographic silicon etching, and metal deposition. Polarization measurements of coupling demonstrate a preference to the TM-aligned mode, as predicted in simulations.

An automated method for determining whether dairy cows with subclinical mammary infections recover after antibiotic treatment would be a useful tool in dairy production. For that purpose, inline L-lactate dehydrogenase (LDH) measurements was modeled using a dynamic linear model; the variance parameters were estimated using the expectation-maximization algorithm. The method used to classify cows as infected or uninfected was based on a multiprocess Kalman filter. Two learning data sets were created: infected and uninfected. The infected data set consisted of records from 48 cows with subclinical Staphylococcus aureus infection from 4 herds collected in 2010. The uninfected data set came from 35 uninfected cows collected during 2013 from 2 herds. Bacteriological culturing was used as gold standard. To test the model, we collected data from the 48 infected cows 50 d after antibiotic treatment. As a result of the treatment, this test data set consisted of 25 cows that still had a subclinical infection and 23 cows that were recovered. Model sensitivity was 36.0% and specificity was 82.6%. To a large extent, L-lactate dehydrogenase reflected the cow's immune response to the presence of pathogens in the udder. However, cows that were classified correctly before treatment had a better chance of correct classification after treatment. This indicated a variation between cows in immune response to subclinical mammary infection that may complicate the detection of subclinically infected cows and determination of recovery.

Sequencing the genomes of individual cells enables the direct determination of genetic heterogeneity amongst cells within a population. We have developed an injection-moulded valveless microfluidic device in which single cells from colorectal cancer derived cell lines (LS174T, LS180 and RKO) and fresh colorectal tumors have been individually trapped, their genomes extracted and prepared for sequencing using multiple displacement amplification (MDA). Ninety nine percent of the DNA sequences obtained mapped to a reference human genome, indicating that there was effectively no contamination of these samples from non-human sources. In addition, most of the reads are correctly paired, with a low percentage of singletons (0.17 +/- 0.06%) and we obtain genome coverages approaching 90%. To achieve this high quality, our device design and process shows that amplification can be conducted in microliter volumes as long as the lysis is in sub-nanoliter volumes. Our data thus demonstrates that high quality whole genome sequencing of single cells can be achieved using a relatively simple, inexpensive and scalable device. Detection of genetic heterogeneity at the single cell level, as we have demonstrated for freshly obtained single cancer cells, could soon become available as a clinical tool to precisely match treatment with the properties of a patient's own tumor.

The absorption in amorphous silicon nano antennas is engineered for the purpose of post process structural change via resonant laser printing by illumination, thus shifting transmission and reflection spectrum in a controlled manner.

Conventional three-dimensional optics requires curvature to control the wave front of light thus making it difficult to reduce the size of the optical systems. Furthermore, for correction of optical aberrations, complex optical systems comprising more than one lens are used. This adds additional bulk, mass and complexity to the optical systems. Recent development in diffractive optics has enabled new thin lightweight optical elements such as metalenses. We introduce resonant laser printing technique as a flexible photo-thermal technology for metalens fabrication with the ability to control the light with microscale precision. Our laser printed metalenses can be integrated in bio-sensors, bio-imaging systems, and optofluidical devices.

Spatially offset Raman spectroscopy (SORS) enables one to distinguish chemical fingerprints of top and subsurface layers. In this paper, we apply SORS to a microfluidic two-layer system consisting of transparent liquid in a microchannel as the surface layer and microfluidic PDMS chip material as the sublayer. By using an imaging spectrograph connected to a microscope, we perform hyperspectral SORS acquisitions. Furthermore, the focus position z is translated. Thus, we combine the two methods of hyperspectral SORS and defocusing micro-SORS, which leads to an integral characterization of the layered system. The collected top and subsurface layers of Raman scattering at the optical axis (zero spatial offset) largely depends on the focus position z. However, the spatially offset Raman scattered intensity from the subsurface layer is constant for a large range of focus positions z. We claim that there is potential for internal referencing and alignment reproducibility. We demonstrate these findings experimentally in a microfluidic scenario where a 16 mu m deep channel is filled with an aqueous hemoglobin solution. Our observation enables consistent concentration measurements in small-volume liquid samples. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

A waveguide Young interferometer is presented with simultaneous detection of complex refractive index of a liquid sample. The real part of the refractive index change (refraction) is detected by tracing phase shifts of the interferogram generated by a sensing and reference waveguide. The imaginary part of the refractive index (absorption) is determined by the attenuation of the transmitted signal at certain wavelength. Furthermore, nano-filters are fabricated atop the sensing waveguide, which enables size-exclusion filtering of species to the evanescent field. It shows capability of distinguishing small and large particles from 100 nm to 500 nm in diameter, which is further confirmed by fluorescent excitation experiments. The present sensor could find broad application in optical characterization of complex turbid media with regard to their complex refractive index.

International audience; The REvolutionary Approaches and Devices for Nucleic Acid analysis (READNA) project received 12 million s funding under the European Union Framework Programme 7 from 1st June 2008 to 30th November 2012. The 19 project partners from both academia and industry from in total 7 countries had a project budget of 16 Ms with which they have discovered, created and developed a huge body of insights into nucleic acid analysis. Results have been presented widely in publications and in innumerous public presentations. Results have been moved to spin-offs such as the Olink enrichment kits (now sold by Agilent as Haloplex) and are findingtheir way to the market, such as the Oxford Nanopore MinIon sequencer that was first released to early-access user sites in 2014.

A metric for evaluation of overall metalens performance is presented. It is applied to determination of optimal operating spectral range of a metalens, both theoretically and experimentally. This metric is quite general and can be applied to the design and evaluation of future metalenses, particularly achromatic metalenses.

We demonstrate resonance Raman spectroscopy in microfluidic channels for the analysis of whole blood. In particular, cell-free plasma layers are created in microfluidic whole blood flow by means of temporary hydrodynamic cell filter functionality. In-line confocal Raman spectroscopy is applied at the location of the created cell-free plasma layer and we detect free hemoglobin at diagnostic relevant hemolysis concentrations. Raman spectroscopy is a semi-quantitative method for chemical analysis. Due to the uniqueness of molecular vibrations, its selectivity is dependable. However, Raman scattering intensity is often too weak to be detected. This weakness can be overcome by resonance Raman spectroscopy where the laser excitation frequency is chosen corresponding to a dipole-allowed electronic transition of the molecule under study [1]. By employing resonance Raman spectroscopy we investigate bovine blood samples inside microfluidic channels in a micro-Raman setup, putting analytical emphasis on hemoglobin. Resonance Raman spectroscopy of hemoglobin was first demonstrated in 1972 [2] where aqueous solutions with concentrations of approximately 10-4 M were examined. Here we detect hemoglobin dissolved in bovine blood plasma inside 40μm deep PDMS channels. Most dominantly in our Raman spectra, the characteristic oscillatory mode of the central porphyrin ring structure of hemoglobin at 1375cm-1 appears. Despite the background in the Raman spectrum due to fluorescent emission from plasma proteins we are able to detect hemoglobin at concentrations from as low as 10-5 M and higher. The range of clinical relevance for hemolysis can be accurately resolved. The chemical analysis of liquid suspensions is of major interest to e.g. food industry, biotechnology and chemical industry. In this respect, it is desired to separate the suspending liquid from diluted particles, cells or beads [3]. A temporary particle or cell separation as proposed here is sufficient in order to analyze the suspending liquid in transit by micro-Raman spectroscopy. The microfluidic PDMS channels used in our whole blood experiments are 30-60μm wide and 40μm deep. In general, blood cells in flowing blood tend to migrate to the center of a microfluidic channel (Fahraeus–Lindqvist effect [4]), leaving a cell-free plasma region of 1-3μm at the channel walls. This cell-free plasma region can be locally expanded by the sudden enlargement of the microfluidic channel. In this way we create expanded semi-stagnant cell-free blood plasma regions of 5-20μm in width in close vicinity to whole blood flow. These regions are large enough to enable the application of localized confocal Raman spectroscopy exclusively in cell-free blood plasma. Hemolysis levels of whole bovine blood have been determined in this way. [1] M.D. Morris, D.J. Wallan, Anal. Chem., 51, 182–192 (1979) [2] T.C. Strekas and T.G. Spiro, Biochim. Biophys. Acta, 263, 830-833 (1972) [3] T. Kulrattanarak, R.G,M van der Sman, C.G. Schroen, R.M. Boom, Adv. Colloid Interface Sci, 142, 53-66 (2008) [4] R. Fahraeus, T. Lindqvist, The American Journal of Physiology, 96, 562–568 (1931)

Hemolysis is the rupture of the red blood cells (RBCs) with consequent release of hemoglobin to the blood plasma. To detect hemolysis, the red blood cells have to be separated from the blood plasma. Current clinical methods require centrifugation steps for cell/plasma separation, which is time consuming and not suitable for integration into Point-of-Care (PoC) devices. The lack of a fast and reliable PoC hemolysis detection is a central cause of hemolysis being the largest source of unsuitable samples received in clinical laboratories worldwide. Here, we present an optofluidic approach to address this issue. To measure the free hemoglobin in plasma of whole blood, evanescent waveguide absorption is accomplished in wavelength range of 400-430 nm, where hemoglobin has the strongest absorption. For separation of the RBCs, nano-filters are imprinted on top of the waveguide, enabling local blocking of RBCs from the evanescent field region. By this means, our sensor is able to accomplish hemolysis detection on whole blood without any need of sample preparation such as centrifugation. Various nano-imprint techniques are employed to define the gratings couplers (368 nm pitch) and nano-filters(400 nm pitch). The sensor is fabricated on a flexible polymer membrane, enabling easy integration. The nano-imprint fabrication used here allows easy up-scaling for industrial adaption. Furthermore, we use gratings couplers to disperse the guided broadband light and accomplish spectral analysis with a linear camera, which enables highly compact optical setup. We tested the hemolysis sensor integrated in a modified commercial PoC blood gas analyzer. Whole blood and plasma with different free hemoglobin concentrations are tested, proving the filtering ability of the sensor. Detecting interference from other blood proteins such as bilirubin is successfully demonstrated by spectral analysis algorithm. Long-term tests for more than a month further show its high repeatability, specificity, and reliability. We envision large potential in improving PoC blood diagnostic quality by our sensor as well as further applications in optical detection in turbid media.

This paper describes digital printing of optical metasurfaces, by holographic laser post-writing on nano-textured, metal-coated template surfaces. Holographic laser printing with a spatial light modulator (SLM) provides multiple pixel exposure and high power endurance, where individual template nano-stuctures are thermo-optically modified by resonant absorption. Ultra-high printing resolution, beyond 100,000 Dots per inch (DPI) is achieved - enabling nano-scale digital laser printing for mass customization of optical components and individualized decoration of consumer products. We present laser printed structural colors and flat optics components, such as Fresnel Zone Plates (FZP) and Axicons.

A photonic crystal slab (PCS) sensor is a universal refractive index sensor with possibilities and performance very similar to surface plasmon resonance (SPR), which represents the gold standard of biosensing. Cheap PCS sensors can be made vacuum-free entirely out of polymers, but come with additional challenges, besides those relating to temperature-variations, which must be considered in any refractive index based method: The polymeric waveguide core was found to swell by ∼0.3% as water absorbed into the waveguide core over ∼1.5 h. This was investigated by monitoring the wavelength of resonant reflection during absorption, by monitoring the release of water using ellipsometry, and by rigorous coupled-wave analysis (RCWA). The approach presented here enables monitoring of water uptake and thermal fluctuations, for drift-free, high-performance operation of a polymeric PCS sensor.

Sequencing the genomes of individual cells enables the direct determination of genetic heterogeneity amongst cells within a population. We have developed an injection-moulded valveless microfluidic device in which single cells from colorectal cell (LS174T, LS180 and RKO) lines and fresh colorectal cancers are individually trapped, their genomes extracted and prepared for sequencing, using multiple displacement amplification (MDA). Ninety nine percent of the DNA sequences obtained mapped to a reference human genome, indicating that there was effectively no contamination of these samples from non-human sources. In addition, most of the reads are correctly paired, with a low percentage of singletons (0.17 ± 0.06 %) and we obtain genome coverages approaching 90%. To achieve this high quality, our device design and process shows that amplification can be conducted in microliter volumes as long as extraction is in sub-nanoliter volumes. Our data also demonstrates that high quality single cell sequencing can be achieved using a relatively simple, inexpensive and scalable device.

Laser printing with a spatial light modulator (SLM) has several advantages over conventional raster-writing and dot-matrix display (DMD) writing: multiple pixel exposure, high power endurance and existing software for computer generated holograms (CGH). We present a technique for the design and manufacturing of plasmonic metasurfaces based on ultrafast laser printing with an SLM. As a proof of principle, we have used this technique to laser print a plasmonic metalens as well as high resolution plasmonic color decorations. The high throughput holographic resonant laser printing (HRLP) approach enables on-demand mass-production of customized metasurfaces., Comment: Supplementary information is available upon request to authors

We demonstrate a microfluidic reaction chamber that mimics a microcentrifuge tube where reagents can be mixed sequentially at a known stoichiometry. The device has no moving parts or valves and is made by hot embossing in a polymer foil. Sample and reagents are filled in the reaction chamber by controlled guiding of the air/liquid interface in a rectangular array of pillars. The operation of the device is demonstrated by performing isothermal DNA amplification in nL volumes. In our device, 28 pg of DNA from λ-phage, a virus with a 48 kilo base genome, is amplified 500 times thus the amplification product is suitable for library preparation for second generation sequencing. We show that fabrication by hot embossing does not introduce significant contamination and that our device is performing comparably well to test tube amplification and current PDMS-based chip technology.

To elucidate cellular diversity and clonal evolution in tissues and tumors, one must resolve genomic heterogeneity in single cells. To this end, we have developed low-cost, mass-producible micro-/nanofluidic chips for DNA extraction from individual cells. These chips have modules that collect genomic DNA for sequencing or map genomic structure directly, on-chip, with denaturation-renaturation (D-R) optical mapping [Marie R, et al. (2013) Proc Natl Acad Sci USA 110:4893-4898]. Processing of single cells from the LS174T colorectal cancer cell line showed that D-R mapping of single molecules can reveal structural variation (SV) in the genome of single cells. In one experiment, we processed 17 fragments covering 19.8 Mb of the cell's genome. One megabase-large fragment aligned well to chromosome 19 with half its length, while the other half showed variable alignment. Paired-end single-cell sequencing supported this finding, revealing a region of complexity and a 50-kb deletion. Sequencing struggled, however, to detect a 20-kb gap that D-R mapping showed clearly in a megabase fragment that otherwise mapped well to the reference at the pericentromeric region of chromosome 4. Pericentromeric regions are complex and show substantial sequence homology between different chromosomes, making mapping of sequence reads ambiguous. Thus, D-R mapping directly, from a single molecule, revealed characteristics of the single-cell genome that were challenging for short-read sequencing.