Washable, Low-Temperature Cured Joints for Textile-Based Electronics

Low-temperature die-attaching pastes for wearable electronics are the key components to realize any type of device where components are additively manufactured by pick and place techniques. In this paper, the authors describe a simple method to realize stretchable, bendable, die-attaching pastes based on silver flakes to directly mount resistors and LEDs onto textiles. This paste can be directly applied onto contact pads placed on textiles by means of screen and stencil printing and post-processed at low temperatures to achieve the desired electrical and mechanical properties below 60 °C without sintering. Low curing temperatures lead to lower power consumption, which makes this paste ecological friendly

Materials and Concepts for Textile Sensor Systems: Presentation held at 9th International Conference on Materials for Advanced Technologies (ICMAT 2017); Singapur; 18.-23.06.2017

In recent years, the integration of electronics in textiles has gained increasing attention. In order to make the step towards industrial manufacturing of wearable electronics as well as smart technical textiles it is necessary to develop modular concepts as well as integration processes suitable for high volume production. By introducing new concepts for electronic packaging and interconnects, a seamless, comfortable and robust integration of electronics in textiles is possible. Besides the large area technical textiles with integrated sensors for structural health monitoring and environmental conditions, smart garments for the monitoring of movement and physiological parameters play the most important role. These systems can cover various aspects: prevention, diagnosis, therapy and rehabilitation. For these applications sensors can be textile based but also miniaturized conventional sensors can be required. Different polymers and metals can be used as yarns, printable pastes or foils to realize a broad range of measurement principles. While the performance of textile and polymer sensors cannot compete with conventional sensors, the mechanical properties of these materials allow completely new applications, e.g. in strain measurements. The mechanical reliability is essential for smart textiles. Especially different degrees of stretchability and drapeability have to be achieved while maintaining the sensor properties. Various diagnostic sensor systems have been developed over the last decade and the feasibility of ECG and EMG is proven, there are not a lot of products on the market yet. Systems which fulfill lower requirements can be used e.g. in prevention. Currently a major trend in prevention can be seen in posture and movement monitoring as the number of patients having problems with their musculoskeletal system grows continuously. This type of application has the advantage to be also applicable in sports where the barriers for market entrance are much lower

Thin Film Encapsulation for LCP-Based Flexible Bioelectronic Implants: Comparison of Different Coating Materials Using Test Methodologies for Life-Time Estimation

Liquid crystal polymer (LCP) has gained wide interest in the electronics industry largely due to its flexibility, stable insulation and dielectric properties and chip integration capabilities. Recently, LCP has also been investigated as a biocompatible substrate for the fabrication of multielectrode arrays. Realizing a fully implantable LCP-based bioelectronic device, however, still necessitates a low form factor packaging solution to protect the electronics in the body. In this work, we investigate two promising encapsulation coatings based on thin-film technology as the main packaging for LCP-based electronics. Specifically, a HfO2–based nanolaminate ceramic (TFE1) deposited via atomic layer deposition (ALD), and a hybrid Parylene C-ALD multilayer stack (TFE2), both with a silicone finish, were investigated and compared to a reference LCP coating. T-peel, water-vapour transmission rate (WVTR) and long-term electrochemical impedance spectrometry (EIS) tests were performed to evaluate adhesion, barrier properties and overall encapsulation performance of the coatings. Both TFE materials showed stable impedance characteristics while submerged in 60 °C saline, with TFE1-silicone lasting more than 16 months under a continuous 14V DC bias (experiment is ongoing). The results presented in this work show that WVTR is not the main factor in determining lifetime, but the adhesion of the coating to the substrate materials plays a key role in maintaining a stable interface and thus longer lifetimes.Bio-Electronic

Imaging the Cytokine Receptor CXCR4 in Atherosclerotic Plaques with the Radiotracer (68)Ga-Pentixafor for PET

Ga-pentixafor is a radiotracer for PET that binds with nanomolar affinity to CXCR4. The CXCR4 receptor is expressed at the surface of inflammatory cells. The objective of the study was to analyze the ability of radiolabeled pentixafor to detect CXCR4 expression on inflammatory cells present in atherosclerotic plaques of an experimental rabbit model. Atherosclerotic plaques were induced by endothelial abrasion of the right carotid artery and abdominal aorta of 7 rabbits fed an atherogenic diet. Five noninjured rabbits fed a chow diet were used as controls. Rabbits were imaged on a PET/MR system after injection of Ga-pentixafor (15 MBq/kg). Vascular signal was quantified as tissue-to-background ratio (TBR). Biodistribution and autoradiographic studies were performed 1 h after injection of I-pentixafor (7.5 MBq/kg). In addition, blocking studies were performed in 2 atherosclerotic rabbits with preinjection of the CXCR4 inhibitor AMD3100. Tracer uptake was quantified on arterial cryosections using autoradiography and compared with CXCR4 and RAM-11 (macrophage) expression on adjacent histologic sections. One hour after injection of Ga-pentixafor, strong signals were detected in vivo with PET/MR imaging in atherosclerotic plaques of the abdominal aorta and right carotid artery as compared with normal control arteries (mean TBR = 1.95 ± 0.51 vs. 1.22 ± 0.25 and mean TBR = 1.24 ± 0.38 vs. 0.96 ± 0.37, respectively; < 0.05 for both). Blocking studies with preinjection of a CXCR4 inhibitor reduced I-pentixafor uptake in atherosclerotic plaques by approximately 40%. I-pentixafor uptake in the vessel wall on autoradiographies was located in macrophage-rich regions of atherosclerotic plaques and correlated with the intensity of CXCR4 expression on corresponding cryosections ( = 0.61; < 0.05). Ga-pentixafor allows for the noninvasive detection of CXCR4 expression in the vessel wall with PET and emerges as a potential alternative to F-FDG for the assessment of macrophage infiltration in atherosclerotic plaques