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Biomedical Microdevices

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https://www.readbyqxmd.com/read/28634847/carbon-nanotubes-embedded-in-embryoid-bodies-direct-cardiac-differentiation
#1
Samad Ahadian, Shukuyo Yamada, Mehdi Estili, Xiaobin Liang, Ramin Banan Sadeghian, Ken Nakajima, Hitoshi Shiku, Tomokazu Matsue, Ali Khademhosseini
We embedded carbon nanotubes (CNTs) in mouse embryoid bodies (EBs) for modulating mechanical and electrical cues of the stem cell niche. The CNTs increased the mechanical integrity and electrical conductivity of the EBs. Measured currents for the unmodified EBs (hereafter, EBs) and the EBs-0.25 mg/mL CNTs were 0.79 and 26.3 mA, respectively, at voltage of 5 V. The EBs had a Young's modulus of 20.9 ± 6.5 kPa, whereas the Young's modulus of the EB-0.1 mg/mL CNTs was 35.2 ± 5.6 kPa. The EB-CNTs also showed lower proliferation and greater differentiation rates compared with the EBs as determined by the expression of pluripotency genes and the analysis of EB sizes...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28620782/role-of-key-genetic-mutations-on-increasing-migration-of-brain-cancer-cells-through-confinement
#2
Loan Bui, Sayem H Bhuiyan, Alissa Hendrick, Cheng-Jen Chuong, Young-Tae Kim
Uncontrolled invasive cancer cell migration is among the major challenges for the treatment and management of brain cancer. Although the genetic profiles of brain cancer cells have been well characterized, the relationship between the genetic mutations and the cells' mobility has not been clearly understood. In this study, using microfluidic devices that provide a wide range of physical confinements from 20 × 5 μm(2) to 3 × 5 μm(2) in cross sections, we studied the effect of physical confinement on the migratory capacity of cell lines with different types of mutations...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28612283/cell-laden-microgel-prepared-using-a-biocompatible-aqueous-two-phase-strategy
#3
Yang Liu, Natalia Oshima Nambu, Masahito Taya
Microfluidic methods are frequently used to produce cell-laden microgels for various biomedical purposes. Such microfluidic methods generally employ oil-water systems. The poor distribution of crosslinking reagents in the oil phase limits the available gelation strategies. Extracting the microgel from the oil-phase also reduces its production efficiency. In this study, an aqueous two-phase system (ATPS) involving dextran (DEX) and polyethylene glycol (PEG) was used to prepare cell-laden microgel. This avoided the problems associated with an oil phase...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28612282/probing-of-peripheral-blood-mononuclear-cells-anchoring-on-tnf-alpha-challenged-vascular-endothelia-in-an-in-vitro-model-of-the-retinal-microvascular
#4
Yuan Li, Yao Lu, Qiong Chen, Yuejun Kang, Ling Yu
Retinopathy is a complication of diabetes that affects the eyes; it stems from damage to the microvasculature of the retina and eventually compromises vision. The diagnosis of retinopathy is difficult to make because there are no early symptoms or warning signs. Dysfunction of the retina's microvascular networks is believed to be associated with inflammatory cytokines and tumor necrosis factor alpha (TNF-α). To investigate the effect of these cytokines, such as TNF-α, a polydimethylsiloxane (PDMS)/glass hydride microfluidic device reflecting the physiological structure of the retina's microvasculature was developed...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28608128/fabrication-of-highly-modulable-fibrous-3d-extracellular-microenvironments
#5
Xixiang Zhang, Fangfei Han, Ahad Syed, Ebtihaj M Bukhari, Basil Chew Joo Siang, Shan Yang, Bingpu Zhou, Wei-Jia Wen, Dechen Jiang
Three-dimensional (3D) in vitro scaffolds that mimic the irregular fibrous structures of in vivo extracellular matrix (ECM) are critical for many important biological applications. However, structural properties modulation of fibrous 3D scaffolds remains a challenge. Here, we report the first highly modulable 3D fibrous scaffolds self-assembled by high-aspect-ratio (HAR) microfibers. The scaffolds structural properties can be easily tailored to incorporate various physical cues, including geometry, stiffness, heterogeneity and nanotopography...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28597392/packaging-of-implantable-accelerometers-to-monitor-epicardial-and-endocardial-wall-motion
#6
Luigi Brancato, Tristan Weydts, Wouter Oosterlinck, Paul Herijgers, Robert Puers
Acceleration signals, collected from the inner and the outer heart wall, offer a mean of assessing cardiac function during surgery. Accelerometric measurements can also provide detailed insights into myocardial motion during exploratory investigations. Two different implantable accelerometers to respectively record endocardial and epicardial vibrations, have been developed by packaging a commercially available capacitive transducer. The same coating materials have been deposited on the two devices to ensure biocompatibility of the implants: Parylene-C, medical epoxy and Polydimethylsiloxane (PDMS)...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28577265/on-the-injectability-of-free-standing-magnetic-nanofilms
#7
Silvia Taccola, Virginia Pensabene, Toshinori Fujie, Shinji Takeoka, Nicola M Pugno, Virgilio Mattoli
Free-standing films with sub-micrometric thickness, composed of soft polymers and functional nanostructures are promising candidates for many potential applications in the biomedical field, such as reduced port abdominal surgery. In this work, freely suspended poly(L-lactic acid) nanofilms with controlled morphology embedding superparamagnetic iron oxide nanoparticles were fabricated by spin-coating deposition. The mechanical properties of magnetic nanofilms were investigated by Strain-Induced Elastic Buckling Instability for Mechanical Measurements (SIEBIMM) test...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28560702/hybrid-intracerebral-probe-with-integrated-bare-led-chips-for-optogenetic-studies
#8
Suleman Ayub, Luc J Gentet, Richárd Fiáth, Michael Schwaerzle, Mélodie Borel, François David, Péter Barthó, István Ulbert, Oliver Paul, Patrick Ruther
This article reports on the development, i.e., the design, fabrication, and validation of an implantable optical neural probes designed for in vivo experiments relying on optogenetics. The probes comprise an array of ten bare light-emitting diode (LED) chips emitting at a wavelength of 460 nm and integrated along a flexible polyimide-based substrate stiffened using a micromachined ladder-like silicon structure. The resulting mechanical stiffness of the slender, 250-μm-wide, 65-μm-thick, and 5- and 8-mm-long probe shank facilitates its implantation into neural tissue...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28560701/nano-calorimetry-based-point-of-care-biosensor-for-metabolic-disease-management
#9
Evan Kazura, Brad R Lubbers, Elliott Dawson, John A Phillips, Franz Baudenbacher
Point of care (POC) diagnostics represents one of the fastest growing health care technology segments. Developments in microfabrication have led to the development of highly-sensitive nanocalorimeters ideal for directly measuring heat generated in POC biosensors. Here we present a novel nano-calorimeter-based biosensor design with differential sensing to eliminate common mode noise and capillary microfluidic channels for sample delivery to the thermoelectric sensor. The calorimeter has a resolution of 1.4 ± 0...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28560700/an-improved-design-of-optical-sensor-for-long-term-measurement-of-arterial-blood-flow-waveform
#10
Biljana Djurić, Slavica Suzić, Bojana Stojadinović, Zorica Nestorović, Marija Ivanović, Jelena Suzić-Lazić, Dejan Nešić, Sanja Mazić, Tamar Tenne, Dragoslav Zikich, Dejan Žikić
We present here the improved design and development of optical sensor for non-invasive measurements of arterial blood flow waveform. The sensor is based on a physical principle of reflective photoplethysmography (PPG). As the light source we used serially connected infrared diodes whereas NPN silicon phototransistors were used as light detectors. The electronic components were molded into square package and poured with silicone. Such preparation produced an elastic superficies that allowed excellent attachment of the sensor on the skin's surface...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28540469/a-3d-microfluidic-perfusion-system-made-from-glass-for-multiparametric-analysis-of-stimulus-secretioncoupling-in-pancreatic-islets
#11
Torben Schulze, Kai Mattern, Eike Früh, Lars Hecht, Ingo Rustenbeck, Andreas Dietzel
Microfluidic perfusion systems (MPS) are well suited to perform multiparametric measurements with small amounts of tissue to function as an Organ on Chip device (OOC). Such microphysiolgical characterization is particularly valuable in research on the stimulus-secretion-coupling of pancreatic islets. Pancreatic islets are fully functional competent mini-organs, which serve as fuel sensors and transduce metabolic activity into rates of hormone secretion. To enable the simultaneous measurement of fluorescence and oxygen consumption we designed a microfluidic perfusion system from borosilicate glass by 3D femtosecond laser ablation...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28536859/accelerated-life-test-methods-and-results-for-implantable-electronic-devices-with-adhesive-encapsulation
#12
Xuechen Huang, Petcharat May Denprasert, Li Zhou, Adriana Nicholson Vest, Sam Kohan, Gerald E Loeb
We have developed and applied new methods to estimate the functional life of miniature, implantable, wireless electronic devices that rely on non-hermetic, adhesive encapsulants such as epoxy. A comb pattern board with a high density of interdigitated electrodes (IDE) could be used to detect incipient failure from water vapor condensation. Inductive coupling of an RF magnetic field was used to provide DC bias and to detect deterioration of an encapsulated comb pattern. Diodes in the implant converted part of the received energy into DC bias on the comb pattern...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28536858/quantification-of-micrornas-directly-from-body-fluids-using-a-base-stacking-isothermal-amplification-method-in-a-point-of-care-device
#13
Maggie R Williams, Robert D Stedtfeld, Tiffany M Stedtfeld, James M Tiedje, Syed A Hashsham
MicroRNAs have been proposed to be a class of biomarkers of disease as expression levels are significantly altered in various tissues and body fluids when compared to healthy controls. As such, the detection and quantification of microRNAs is imperative. While many methods have been established for quantification of microRNAs, they typically rely on time consuming handling such as RNA extraction, purification, or ligation. Here we describe a novel method for quantification of microRNAs using direct amplification in body fluids without upstream sample preparation...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28526975/lipid-nanoparticles-for-administration-of-poorly-water-soluble-neuroactive-drugs
#14
Elisabetta Esposito, Markus Drechsler, Paolo Mariani, Federica Carducci, Michela Servadio, Francesca Melancia, Patrizia Ratano, Patrizia Campolongo, Viviana Trezza, Rita Cortesi, Claudio Nastruzzi
This study describes the potential of solid lipid nanoparticles and nanostructured lipid carriers as nano-formulations to administer to the central nervous system poorly water soluble drugs. Different neuroactive drugs, i.e. dimethylfumarate, retinyl palmitate, progesterone and the endocannabinoid hydrolysis inhibitor URB597 have been studied. Lipid nanoparticles constituted of tristearin or tristearin in association with gliceryl monoolein were produced. The nanoencapsulation strategy allowed to obtain biocompatible and non-toxic vehicles, able to increase the solubility of the considered neuroactive drugs...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28364179/applications-and-theory-of-electrokinetic-enrichment-in-micro-nanofluidic-chips
#15
Xueye Chen, Shuai Zhang, Lei Zhang, Zhen Yao, Xiaodong Chen, Yue Zheng, Yanlin Liu
This review reports the progress on the recent development of electrokinetic enrichment in micro-nanofluidic chips. The governing equations of electrokinetic enrichment in micro-nanofluidic chips are given. Various enrichment applications including protein analysis, DNA analysis, bacteria analysis, viruses analysis and cell analysis are illustrated and discussed. The advantages and difficulties of each enrichment method are expatiated. This paper will provide a particularly convenient and valuable reference to those who intend to research the electrokinetic enrichment based on micro-nanofluidic chips...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28357654/human-adipocyte-differentiation-and-characterization-in-a-perfusion-based-cell-culture-device
#16
Yunxiao Liu, Patthara Kongsuphol, Sajay Bhuvanendran Nair Gourikutty, Qasem Ramadan
Adipocytes have gained significant attention recently, because they are not only functioning as energy storage but also as endocrine cells. Adipocytes secret various signaling molecules, including adiponectin, MCP-1, and IL-6, termed collectively as "adipokines". Adipokines regulate glucose metabolism, thereby play an important role in obesity, diabetes type 2, and other metabolic disorders. Conventionally, to study the secretory function, adipocytes are cultured in vitro in static conditions. However, static culturing condition falls short of mimicking the interstitial fluid flows in living systems...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28357653/identifying-drug-resistant-cancer-cells-using-microbubble-well-arrays
#17
Qihui Pu, Ryan Spooner, Lisa A DeLouise
Drug resistance is a characteristic of tumor initiating cells that can give rise to metastatic disease. In this work we demonstrate the use of microbubble well arrays as a cell culture platform to enumerate and characterize drug resistant cells in a human derived tumorigenic squamous cell carcinoma cell line. The spherical architecture and compliant hydrophobic composition of the microbubble well favors single cell survival, clonal proliferation and formation of spheres that do not grow on standard tissue culture plastic and are resistant to cisplatin...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28357652/optimized-acoustic-biochip-integrated-with-microfluidics-for-biomarkers-detection-in-molecular-diagnostics
#18
G Papadakis, J M Friedt, M Eck, D Rabus, G Jobst, E Gizeli
The development of integrated platforms incorporating an acoustic device as the detection element requires addressing simultaneously several challenges of technological and scientific nature. The present work was focused on the design of a microfluidic module, which, combined with a dual or array type Love wave acoustic chip could be applied to biomedical applications and molecular diagnostics. Based on a systematic study we optimized the mechanics of the flow cell attachment and the sealing material so that fluidic interfacing/encapsulation would impose minimal losses to the acoustic wave...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28488167/a-generic-label-free-microfluidic-microobject-sorter-using-a-magnetic-elastic-diverter
#19
Jiachen Zhang, Onaizah Onaizah, Amir Sadri, Eric Diller
Cell sorters play important roles in biological and medical applications, such as cellular behavior study and disease diagnosis and therapy. This work presents a label-free microfluidic sorter that has a downstream-pointing magnetic elastic diverter. Different with most existing magnetic sorters, the proposed device does not require the target microobjects to be intrinsically magnetic or coated with magnetic particles, giving users more flexibility in sorting criteria. The diverter is wirelessly deformed by an applied magnetic field, and its deformation induces a fluid vortex that sorts incoming microobjects, e...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28484917/remote-magnetic-switch-off-microgate-for-nanofluidic-drug-delivery-implants
#20
Marco Farina, Andrea Ballerini, Gianluca Torchio, Giulia Rizzo, Danilo Demarchi, Usha Thekkedath, Alessandro Grattoni
In numerous pathologies, implantable drug delivery devices provide advantages over conventional oral or parenteral approaches. Based on the site of implantation and release characteristics, implants can afford either systemic delivery or local administration, whereby the drug is delivered at or near the site of intended action. Unfortunately, current implantable drug delivery systems provide limited options for intervention in the case of an adverse reaction to the drug or the need for dosage adjustment. In the event that drug delivery must be terminated, an urgent surgical retrieval may be the only reliable option...
June 2017: Biomedical Microdevices
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