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Despite the increasing efforts in improving bone health assessments, current diagnostics suffer from critical shortcomings. The present article therefore describes a multiplex label-free immunosensor designed and validated for the assessment of two bone turnover markers (BTMs), namely beta isomerized C-terminal telopeptide of type I collagen (CTx) and Procollagen I Intact N-Terminal (PINP), the combination of which is needed to illustrate an accurate overview of bone health. The immunosensor was then tested outside and inside of a microsystem, with the aim of becoming compatible with a point of care system fabricated for automated assessment of these biomarkers later-on at patient side. Custom-made monoclonal antibodies were specifically designed for this purpose in order to guarantee the selectivity of the immunosensor. In the final platform, a finger prick blood sample is introduced into the microfluidic manifolds without any need for sample preparation step, making the tool suitable for near patient and outside of the central laboratory applications. The platform was exploited in 30 real blood samples with the results validated using electrochemiluminescence immunoassay. The results revealed the platform was capable of measuring the target analyte with high sensitivity and beyond the recommended clinical reference range for each biomarker (CTx: 104–1028 ng L−1and PINP: 16–96 μg L−1, correspondingly). They also showed the platform to have a limit of detection of 15 (ng L−1) and 0.66 (μg L−1), a limit of quantification of 49 (ng L−1) and 2.21 (μg L−1), and an inter- and intra-assay coefficient of variance of 5.39–6.97% and 6.81–5.37%, for CTx and PINP respectively, which is comparable with the gold standard. The main advantage of the platform over the state-of-the art was the capability of providing the results for two markers recommended for assessing bone health within 15 minutes and without the need for skilled personnel or costly infrastructure.

Objectives: immunosensors are a versatile technology enabling affinity-based detection of a large variety of molecular targets. Their common use in practice, however, is limited due to the instability of the antibodies and therefore shelf-life issues. Despite the negative impact of these challenges on the commercialization of such sensors, not many studies have provided solutions in this regard. This work illustrates how the experience from the food packaging industry could help reduce the negative effect of environmental factors such as O2, humidity, and temperature on the performance of immunosensors and improve their long-term stability. To the best of our knowledge, this approach is completely novel. Methods: Different packaging approaches, namely vacuum packaging, and packaging under modified atmosphere along with multilayer packaging material with good to excellent gas and water barrier properties based on the food packaging studies were compared. The packed samples were exposed to different storage conditions (humidity and temperature) to determine the optimum storage condition. Results: The tray-top-film with Polyamide (PA)/ethylene vinyl alcohol copolymers (EVOH)/PA/polyethylene (PE)/polypropylene (PP) foil, flushed with 100% N2, packed within 2-h after the fabrication of the immunosensor was concluded as the optimum packaging. With regard to relative humidity, values below 50% should be considered during the packaging process and storage to avoid possible dehydration of the immunosensor and so its over time performance loss. When packed under these conditions, the shelf-life of the immunosensor is increased to more than six months even if stored in room temperature.

Surface functionalization with biological macromolecules is an important task for the development of sensor materials, whereby the interaction with other biological materials should be suppressed. In this work, we developed a novel multifunctional poly(2-ethyl-2-oxazoline)-dithiolane conjugate as a versatile linker for gold surface immobilization of amine-containing biomolecules, containing poly(2-ethyl-2-oxazoline) as antifouling polymer, dithiolane for surface immobilization, and activated esters for protein conjugation. First, a well-defined carboxylic acid containing copoly(2-ethyl-2-oxazoline) was synthesized by cationic ring-opening copolymerization of 2-ethyl-2-oxazoline with a methyl ester-containing 2-oxazoline monomer, followed by postpolymerization modifications. The side-chain carboxylic groups were then converted to amine-reactive pentafluorophenyl (PFP) ester groups. Part of the PFP groups was used for the attachment of the dithiolane moiety, which can efficiently bind to gold surfaces. The final copolymer contained 1.4 mol% of dithiolane groups and 4.5 mol% of PFP groups. The copolymer structure was confirmed by several analytical techniques, including NMR spectroscopy and size-exclusion chromatography. The kinetics of the PFP ester aminolysis and hydrolysis demonstrated significantly faster amidation compared to hydrolysis, which is essential for subsequent protein conjugation. Successful coating of gold surfaces with the polymer was confirmed by spectroscopic ellipsometry, showing a polymer brush thickness of 4.77 nm. Subsequent modification of the coated surfaces was achieved using bovine serum albumin as a model protein. This study introduces a novel reactive polymer linker for gold surface functionalization and offers a versatile polymer platform for various applications including biosensing and surface functionalization.

Advancements in wearable technology and smart textiles have also opened new possibilities in the sports and medical fields. One of the examples of a relevant application case can be found in cycling. This paper expands on previous research on stretchable electronics on knit fabrics. It describes the development of stretchable circuits for the lower back position and motion tracking to prevent back pain in recreational (road) cyclists by combining electrical and textile engineering with insights generated in rehabilitation sciences and sports physiotherapy. The research process included developing and testing of the functional circuit integrated into a cycling jersey. Thermoplastic polyurethane films were used for the textile integration process to achieve maximum comfort and after-life disassembly possibility. Reliability tests, e.g. washing (ISO 6330-2012) and tensile tests, were conducted. It is concluded that while mechanical stress during washing cycles remains a serious concern for reliability and durability, the use of water-repellent thermoplastic polyurethane sealing seriously reduces the damage caused by water and detergents.

The packaging industry and the research community are developing new techniques for keeping up the race for increased functionality in smaller packages, and 3D integration is a good option in [...]

This article explains a step-wise protocol to develop an electrochemical sensor to quantify serum levels of C-telopeptide (CTX) crosslinks also known as crosslaps in a matter of minutes and with high level of accuracy. The technique needs only one-step (incubation) and can thus be used for point of care screening. Due to the excellent electrical properties of the as-prepared immunosensor, CTX levels were successfully measured from 1 to 1000 pg/mL. This is while the normal reference of the marker is 50–450 pg/mL, suggesting that the sensor can acceptably detect CTX. The results also showed a good correlation with ECLIA in measuring serum levels of CTX.

Nowadays, microfluidic technologies have widely been employed in developing point-of-care diagnostics to address global health issues because of their potential advantages of low sample and reagent consumption, high throughput and sensitivity, large surface-to-volume ratio, and other benefits related to miniaturization. However, the fabrication of microfluidic channels is commonly costly and requires laboratory-intensive cleaning, photolithography, and etching or baking steps in cleanroom environments, making it difficult to modify. Besides, proper channel enclosure without deforming small features or without clogging of the channel during the bonding process is challenging. The present article aims to demonstrate a cheap, reliable, and rapid method for the fabrication of microfluidic channels using double-sided tapes, enabling not only highly uniform cross-sectional dimensions along the microfluidic channels but also proper adhesion in hybrid systems, composed of different layers. In other words, this technique provides a single-step integration of electrochemical sensors in a microfluidic chip, which could be useful for rapid and low-cost fabrication of microfluidic-based electrochemical sensors.

This paper describes the implementation of a low-cost technology platform for fluorescence-based optochemical sensors made up of arrays of multimode waveguides and coupling structures integrated onto a flexible substrate. Such a configuration is ideal for multi-analyte detection owing to a possibility of future integration of different dyes in each waveguides. The presence of light sources, fluorescent sensing elements and photodetectors in a foil platform makes it a compact optochemical sensor, which has wide-range of applications in medical, biochemical, and environmental diagnostics. Flexible lightguides fabricated using soft-lithography based replication techniques, are used in combination with 45° micromirror coupling structures, having a loss of 0.5dB. Fluorescent dyes are incorporated with the lightguides enabling a detection of shift in fluorescence-peaks in contact with gases, which are read-out at the detection. Initial measurements yielded promising results of the waveguides mixed with fluorescent dyes showing response to toluene.

This paper describes the development of a low-cost technology platform for fluorescence-based optochemical sensors. These sensors were constructed by incorporating fluorescent sensing elements in the core of multimode waveguides or lightguides, and have applications in medical, biochemical and environmental diagnostics. Flexible lightguides were fabricated either with silsesquioxane-based or PDMS-type optical polymers using photolithography or soft-lithography based replication techniques respectively. Spectral transmission characteristics were measured along with loss values obtained by cut-back measurements for several wavelengths from visible to mid-IR. Propagation losses as low as 0.14dB/cm were measured for 50 x 50 m2waveguides. For coupling light in and out of the waveguides, different types of coupling structures, e.g. 45� micromirror plugs were investigated.

A method for measuring the cell gap of liquid-crystal displays (LCDs) is presented. It is based on analyzing the interference spectrum of white light reflected by the LCD. It can be used before or after filling the LCD. The method is applicable for LCDs whose operation is based on the polarization or the scattering of light. Four methods for the calculation of the cell gap are presented. The first method is based on the wavelengths corresponding with the peaks in the interference spectrum. Two other methods use analog and digital filtering techniques to filter out all the irrelevant information in the interference spectrum; the cell gap is then calculated with fast Fourier transform (FFT) or the inverse FFT. In the fourth method an empirical model is fitted to the measured interference spectrum. © 2001 Society of Photo-Optical Instrumentation Engineers.

Conformable electronics, i.e., electronics that can be applied on curved surfaces, is demanded nowadays in place of conventional rigid printed circuit board (PCB) based electronics for a number of applications. In the field of stretchable electronics there has been a swift progress in recent years. In this paper we are presenting our contribution to this ever growing topic, including thin-film based polyimide (PI), supported Au stretchable meanders as well as PCB based Cu meanders. These meanders are supported by PI or poly(ethylene naphthalate)/poly(ethylene terephthalate) (PEN/PET) films. Thin-film based stretchable interconnects is targeting mainly the biocompatible environments with demands for strong miniaturization while the PCB based technology is used more for large area applications. Both approaches are reviewed in this paper in terms of fabrication processes, materials and cyclic fatigue reliability. For each technology fabricated demonstrators are presented as well.

This paper presents a study of selective ablation of thin organic films (LEP- Light Emitting Polymer, PEDOT:PSS- Poly 3,4-ethylenedioxythiophene: polystyrene sulfonate) by using 248 nm Excimer laser, on various kinds of multilayered SiN barrier foils for the development of Organic Light Emitting Diodes (OLED). Different Silicon Nitride (SiN) barrier foils with dedicated absorption spectra are taken into account for this purpose. The drive for looking into different types of SiN originates from the fact that the laser selective removal of a polymer without damage to the barrier layer underneath is challenging in the dynamic laser processing of thin films. The barrier is solely responsible for the proper encapsulation of the OLED stack. The main limitation of current OLED design is its shorter life span, which is directly related to the moisture or water permeation into the stack, leading to black spots. An optimization of laser parameters like fluence and number of shots has been carried out for the various types of SiN barrier foils. We are able to obtain a wider working process window for the selective removal of LEP and PEDOT:PSS from SiN barrier, by variation of the different types of SiN.