Compact Quad-band Meandered Implantable PIFA for Wireless Brain Care

In the growing efforts of promoting patients' life quality through health technology solutions, implantable wireless biomedical telemetry systems have been identified as one of the frontrunners. In these systems, the design of implantable antennas is of prime importance in establishing the wireless data link. Small multitasking implantable antennas are an evolving wireless health technology for monitoring medical conditions. These implantable antennas are intended for different functions including wireless data transmission at Medical Device Radiocommunication Service (MedRadio) band (401-406 MHz) and Wireless Medical Telemetry Service (WMTS) bands (1395-1400, and 1427-1432), wireless power transfer, and control signals between sleep/wake-up modes at Industrial, Scientific, and Medical (ISM) bands (902-928 MHz and 2400-2483.5 MHz), respectively. In this paper, we present a meandered quad-band planar inverted-F antenna (PIFA) for wireless brain care. Employing the meandering miniaturizing technique, shorting the radiator to the ground plane, and high-permittivity substrate/superstrate layers (Rogers RO3210; varepsilon {r}=10.2, tan delta=0.003, h=0.635 mm) lead to downsizing the antenna volume greatly to 11 times 20.5 times 1.8 mm{3} that includes the biocompatible silicone coating. We developed and characterized the proposed antenna numerically utilizing a 7-layer human head model in full-wave electromagnetic field simulation, where the antenna was implanted in the cerebrospinal fluid (CSF) layer at the depth of 13.25 mm in the cranial cavity. Overall, we achieve a compact quad-band implantable PIFA with-42.3 dBi of gain with a radiation efficiency of 0.003 % at 402 MHz,-22.7 dBi gain with a radiation efficiency of 0.1 % at 902 MHz,-23.7 dBi gain with a radiation efficiency of 0.1 % at 1430 MHz, and-29.7 dBi gain with a radiation efficiency of 0.02 % at 2450 MHz. To our knowledge, this is the first self-matched quad-band antenna proposed for wireless implant communications.Peer reviewe

Building blocks of microphysiological system to model physiology and pathophysiology of human heart

Microphysiological systems (MPS) are drawing increasing interest from academia and from biomedical industry due to their improved capability to capture human physiology. MPS offer an advanced in vitro platform that can be used to study human organ and tissue level functions in health and in diseased states more accurately than traditional single cell cultures or even animal models. Key features in MPS include microenvironmental control and monitoring as well as high biological complexity of the target tissue. To reach these qualities, cross-disciplinary collaboration from multiple fields of science is required to build MPS. Here, we review different areas of expertise and describe essential building blocks of heart MPS including relevant cardiac cell types, supporting matrix, mechanical stimulation, functional measurements, and computational modelling. The review presents current methods in cardiac MPS and provides insights for future MPS development with improved recapitulation of human physiology.Peer reviewe

A Transparent Strain Sensor Based on PDMS-Embedded Conductive Fabric for Wearable Sensing Applications

© 2018 IEEE. In this paper, we present a new approach to realize flexible transparent strain sensors. It combines the use of transparent conductive fabric with polydimethylsiloxane (PDMS) through a simple and straightforward layer-by-layer assembly process. The conductive fabric is used to realize the transparent electrodes while the PDMS is utilized as both the substrate and encapsulation layers. As a concept demonstration, an interdigital capacitive sensor is designed and fabricated using the proposed approach. The fabricated sensor is then characterized in terms of its transparency and electro-mechanical nature. This is followed by the application of the sensor in several physiological sensing scenarios, including the sensing of various body-part movements and tactile sensing. Apart from a high optical transparency (70%), the sensor shows promising sensing results which validate the applicability of the proposed approach for realization of flexible and transparent strain sensors for wearable sensing applications

Fabrication and characterization of graphene antenna for low-cost and environmentally friendly RFID tags

We present the fabrication and testing of graphene-based dipole antennas on cardboard which is a promising low-cost, recyclable, and flexible substrate for future wireless electronics. The article presents the details of the manufacturing, as well as results from the measurements and simulations. The measured sheet resistance of graphene antenna is 1.9 Ω/sq. Overall, a graphene-based planar dipole antenna with the length of 143 mm achieved the measured total efficiency of 40% and the realized gain of –2.18 dBi at 889 MHz. Moreover, a passive ultra-high-frequency radio-frequency tag based on a graphene dipole antenna on cardboard achieved the attainable read range of more than five meters at 950 MHz.acceptedVersionPeer reviewe

Novel Polypyrrole-Coated Polylactide Scaffolds Enhance Adipose Stem Cell Proliferation and Early Osteogenic Differentiation

An electrically conductive polypyrrole (PPy) doped with a bioactive agent is an emerging functional biomaterial for tissue engineering. We therefore used chondroitin sulfate (CS)-doped PPy coating to modify initially electrically insulating polylactide resulting in novel osteogenic scaffolds. In situ chemical oxidative polymerization was used to obtain electrically conductive PPy coating on poly-96L/4D-lactide (PLA) nonwoven scaffolds. The coated scaffolds were characterized and their electrical conductivity was evaluated in hydrolysis. The ability of the coated and conductive scaffolds to enhance proliferation and osteogenic differentiation of human adipose stem cells (hASCs) under electrical stimulation (ES) in three-dimensional (3D) geometry was compared to the noncoated PLA scaffolds. Electrical conductivity of PPy-coated PLA scaffolds (PLA-PPy) was evident at the beginning of hydrolysis, but decreased during the first week of incubation due to de-doping. PLA-PPy scaffolds enhanced hASC proliferation significantly compared to the plain PLA scaffolds at 7 and 14 days. Furthermore, the alkaline phosphatase (ALP) activity of the hASCs was generally higher in PLA-PPy seeded scaffolds, but due to patient variation, no statistical significance could be determined. ES did not have a significant effect on hASCs. This study highlights the potential of novel PPy-coated PLA scaffolds in bone tissue engineering