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Biomedical Microdevices

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https://www.readbyqxmd.com/read/28540469/a-3d-microfluidic-perfusion-system-made-from-glass-for-multiparametric-analysis-of-stimulus-secretioncoupling-in-pancreatic-islets
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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
https://www.readbyqxmd.com/read/28484916/monoolein-aqueous-dispersions-as-a-delivery-system-for-quercetin
#11
Rita Cortesi, Enrica Cappellozza, Markus Drechsler, Catia Contado, Anna Baldisserotto, Paolo Mariani, Federica Carducci, Alessandra Pecorelli, Elisabetta Esposito, Giuseppe Valacchi
This study describes the preparation, characterization and in vitro release of monoolein aqueous dispersions (MAD) encapsulating quercetin (QT). As emulsifier, sodium cholate was employed at two different concentrations, namely 0.15% and 0.25% with respect to the total weight of the formulation. Cryogenic Transmission electron microscopy and X-ray analysis indicated that MAD015 are a mixture of vesicles and cubic structures, whilst MAD025 are mainly characterized by unilamellar vesicular structures. Photon correlation spectroscopy (PCS) and Sedimentation Field Flow Fractionation (SdFFF) showed a MAD size higher than 300 nm that over 100 days from analysis reduces up to 200 nm...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28466286/fabrication-of-cyclo-olefin-polymer-microfluidic-devices-for-trapping-and-culturing-of-yeast-cells
#12
Sevde Puza, Elif Gencturk, Irem E Odabasi, Emre Iseri, Senol Mutlu, Kutlu O Ulgen
A microfluidic platform is designed and fabricated to investigate the role of uncharacterized YOR060C (Sld7) protein in aging in yeast cells for the first time. Saccharomyces cerevisiae yeast cells are trapped in the series of C-shaped regions (0.5 nL) of COP (cyclo olefin polymer), PMMA (poly methylmethacrylate), or PS (polystyrene) microbioreactors. The devices are fabricated using hot embossing and thermo-compression bonding methods. Photolithography and electrochemical etching are used to form the steel mold needed for hot embossing...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28466285/magneto-hydrodynamic-fractionation-mhf-for-continuous-and-sheathless-sorting-of-high-concentration-paramagnetic-microparticles
#13
Vikash Kumar, Pouya Rezai
Sorting cells, microorganisms and particles from a solution is of paramount importance in many biological applications. An ideal sorting device should work at high throughput, involve simple design, avoid energy consumption, operate without a diluting sheath flow and perform separation with high purity. However, currently available sorting methods such as pinched flow fractionation, hydrodynamic filtration, magnetophoresis and deterministic lateral displacement meet only a few of the above-mentioned characteristics...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28466284/a-microfluidic-diode-for-sorting-and-immobilization-of-caenorhabditis-elegans
#14
Lijie Yang, Tao Hong, Yin Zhang, Jose Guillermo Sanchez Arriola, Brian L Nelms, Richard Mu, Deyu Li
Caenorhabditis elegans (C. elegans) is a powerful model organism extensively used in studies of human aging and diseases. Despite the numerous advantages of C. elegans as a model system, two biological characteristics may introduce complexity and variability to most studies: 1. it exhibits different biological features, composition and behaviors at different developmental stages; 2. it has very high mobility. Therefore, synchronization and immobilization of worm populations are often required. Conventionally, these processes are implemented through manual and chemical methods, which can be laborious, time-consuming and of low-throughput...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28451924/microfluidic-gut-on-a-chip-with-three-dimensional-villi-structure
#15
Kyu-Young Shim, Dongwook Lee, Jeonghun Han, Nam-Trung Nguyen, Sungsu Park, Jong Hwan Sung
Current in vitro gut models lack physiological relevance, and various approaches have been taken to improve current cell culture models. For example, mimicking the three-dimensional (3D) tissue structure or fluidic environment has been shown to improve the physiological function of gut cells. Here, we incorporated a collagen scaffold that mimics the human intestinal villi into a microfluidic device, thus providing cells with both 3D tissue structure and fluidic shear. We hypothesized that the combined effect of 3D structure and fluidic shear may provide cells with adequate stimulus to induce further differentiation and improve physiological relevance...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28432532/a-portable-battery-powered-microfluidic-impedance-cytometer-with-smartphone-readout-towards-personal-health-monitoring
#16
Niloy Talukder, Abbas Furniturewalla, Tuan Le, Matthew Chan, Shreyas Hirday, Xinnan Cao, Pengfei Xie, Zhongtian Lin, Azam Gholizadeh, Steve Orbine, Mehdi Javanmard
We present a portable system for personalized blood cell counting consisting of a microfluidic impedance cytometer and portable analog readout electronics, feeding into an analog-to-digital converter (ADC), and being transmitted via Bluetooth to a user-accessible mobile application. We fabricated a microfluidic impedance cytometer with a novel portable analog readout. The novel design of the analog readout, which consists of a lock-in-amplifier followed by a high-pass filter stage for subtraction of drift and DC offset, and a post-subtraction high gain stage, enables detection of particles and cells as small as 1 μm in diameter, despite using a low-end 8-bit ADC...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28432531/effectiveness-of-nanoencapsulated-methotrexate-against-osteosarcoma-cells-in-vitro-cytotoxicity-under-dynamic-conditions
#17
O Mitxelena-Iribarren, C L Hisey, M Errazquin-Irigoyen, Y González-Fernández, E Imbuluzqueta, M Mujika, M J Blanco-Prieto, S Arana
Cancer is a leading cause of mortality in the world, with osteosarcoma being one of the most common types among children between 1 and 14 years old. Current treatments including preoperative chemotherapy, surgery and postoperative chemotherapy produce several side effects with limited effectiveness. The use of lipid nanoparticles as biodegradable shells for controlled drug delivery shows promise as a more effective and targeted tumor treatment. However, in vitro validation of these vehicles is limited due to fluid stagnation in current techniques, in which nanoparticles sediment onto the bottom of the wells killing the cells by asphyxiation...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28432530/an-integrated-microsystem-with-dielectrophoresis-enrichment-and-impedance-detection-for-detection-of-escherichia-coli
#18
Renjie Wang, Yi Xu, Haitao Liu, Jinlan Peng, Joseph Irudayaraj, Feiyun Cui
An integrated microsystem device with matched interdigitated microelectrode chip was fabricated for enrichment and detection of Escherichia coli O157:H7. The microsystem has integrated with positive dielectrophoresis (pDEP) enrichment and in situ impedance detection, whose total volume is only 3.0 × 10(-3) m(3), and could provide impedance testing voltages of 0 ~ 10 V, detection frequencies of 1 KHz ~ 1 MHz, DEP excitation signals with amplitude of 0 ~ 10 Vpp and frequencies of 1KHz ~ 1 MHz, which fully meets the demands of pDEP enrichment and impedance detection for bacteria...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28429183/label-free-okadaic-acid-detection-using-growth-of-gold-nanoparticles-in-sensor-gaps-as-a-conductive-tag
#19
Yuxiang Pan, Zijian Wan, Longjie Zhong, Xueqin Li, Qi Wu, Jun Wang, Ping Wang
Okadaic acid (OA) is a marine toxin ingested by shellfish. In this work, a simple, sensitive and label-free gap-based electrical competitive bioassay has been developed for this biotoxin detection. The gap-electrical biosensor is constructed by modifying interdigitated microelectrodes with gold nanoparticles (AuNPs) and using the self-catalytic growth of AuNPs as conductive bridges. In this development, the AuNPs growth is realized in the solution of glucose and chloroauric acid, with glucose oxidation used as the catalysis for growth of the AuNPs...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28425028/energy-harvesting-from-cerebrospinal-fluid-pressure-fluctuations-for-self-powered-neural-implants
#20
Levent Beker, Arnau Benet, Ali Tayebi Meybodi, Ben Eovino, Albert P Pisano, Liwei Lin
In this paper, a novel method to generate electrical energy by converting available mechanical energy from pressure fluctuations of the cerebrospinal fluid within lateral ventricles of the brain is presented. The generated electrical power can be supplied to the neural implants and either eliminate their battery need or extend the battery lifespan. A diaphragm type harvester comprised of piezoelectric material is utilized to convert the pressure fluctuations to electrical energy. The pressure fluctuations cause the diaphragm to bend, and the strained piezoelectric materials generate electricity...
June 2017: Biomedical Microdevices
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