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Biomedical Microdevices

V N Lad, Swati Ralekar
Development of controlled vacuum is having many applications in the realm of biotechnology, cell transfer, gene therapy, biomedical engineering and other engineering activities involving separation or chemical reactions. Here we show the controlled vacuum generation through a biocompatible, energy efficient, low-cost and flexible miniature device. We have designed and fabricated microfluidic devices from polydimethylsiloxane which are capable of producing vacuum at a highly controlled rate by using water as a motive fluid...
October 2016: Biomedical Microdevices
Sowmya Subramanian, Konstantinos Gerasopoulos, Min Guo, Herman O Sintim, William E Bentley, Reza Ghodssi
Bacterial biofilms are a common cause of chronic medical implant infections. Treatment and eradication of biofilms by conventional antibiotic therapy has major drawbacks including toxicity and side effects associated with high-dosage antibiotics. Additionally, administration of high doses of antibiotics may facilitate the emergence of antibiotic resistant bacteria. Thus, there is an urgent need for the development of treatments that are not based on conventional antibiotic therapies. Presented herein is a novel bacterial biofilm combination treatment independent of traditional antibiotics, by using low electric fields in combination with small molecule inhibitors of bacterial quorum sensing - autoinducer-2 analogs...
October 2016: Biomedical Microdevices
Ning Hu, Jiaru Fang, Ling Zou, Hao Wan, Yuxiang Pan, Kaiqi Su, Xi Zhang, Ping Wang
Cell-based bioassays were effective method to assess the compound toxicity by cell viability, and the traditional label-based methods missed much information of cell growth due to endpoint detection, while the higher throughputs were demanded to obtain dynamic information. Cell-based biosensor methods can dynamically and continuously monitor with cell viability, however, the dynamic information was often ignored or seldom utilized in the toxin and drug assessment. Here, we reported a high-efficient and high-content cytotoxic recording method via dynamic and continuous cell-based impedance biosensor technology...
October 2016: Biomedical Microdevices
Patthara Kongsuphol, Yunxiao Liu, Qasem Ramadan
Cytokine profiling and immunophenotyping offer great potential for understanding many disease mechanisms, personalized diagnosis, and immunotherapy. Here, we demonstrate a time-resolved detection of cytokine from a single cell cluster using an in situ magnetic immune assay. An array of triple-layered microfluidic chambers was fabricated to enable simultaneous cell culture under perfusion flow and detection of the induced cytokines at multiple time-points. Each culture chamber comprises three fluidic compartments which are dedicated to, cell culture, perfusion and immunoassay...
October 2016: Biomedical Microdevices
Yong Yao, Chunsun Zhang
A novel screen-printed microfluidic paper-based analytical device with all-carbon electrode-enabled electrochemical assay (SP-ACE-EC-μPAD) has been developed. The fabrication of these devices involved wax screen-printing, which was simple, low-cost and energy-efficient. The working, counter and reference electrodes were screen-printed using carbon ink on the patterned paper devices. Different wax screen-printing processes were examined and optimized, which led to an improved method with a shorter heating time (~5 s) and a lower heating temperature (75 °C)...
October 2016: Biomedical Microdevices
Hyungseok Cho, Jinho Kim, Song-I Han, Ki-Ho Han
CTCs are currently in the spotlight because provide comprehensive genetic information that enables monitoring of the evolution of cancer and selection of appropriate therapeutic strategies that cannot be obtained from a single-site tumor biopsy. Despite their importance, current techniques for isolating CTCs are limited in terms of their ability to yield high-quality CTCs from peripheral blood for use in profiling cancer genetic mutations by DNA sequencing technologies. This paper introduces a lateral magnetophoretic microseparator (the 'CTC-μChip') for isolating highly pure CTCs from blood, which facilitates the detection of somatic mutations in isolated CTCs...
October 2016: Biomedical Microdevices
J Raczkowska, S Prauzner-Bechcicki
In this work the novel method to create PDMS substrates with continuous and discrete elasticity gradients of different shapes and dimensions over the large areas was introduced. Elastic properties of the sample were traced using force spectroscopy (FS) and quantitative imaging (QI) mode of atomic force microscopy (AFM). Then, fluorescence microscopy was applied to investigate the effect of elastic properties on proliferation of bladder cancer cells (HCV29). Obtained results show that cancerous cells proliferate significantly more effective on soft PDMS, whereas the stiff one is almost cell-repellant...
October 2016: Biomedical Microdevices
Siddarth Chandrasekaran, Ut-Binh T Giang, Lei Xu, Lisa A DeLouise
The metastatic potential of cancer cells is an elusive property that is indicative of the later stages of cancer progression. The ability to distinguish between poorly and highly metastatic cells is invaluable for understanding the basic biology of cancer and to develop more treatments. In this paper, we exploit a A375 melanoma cell line series (A375P, A375MA1, A375MA2) that vary in metastatic potential, to demonstrate an in vitro screening assay using polydimethylsiloxane (PDMS) microbubble well arrays that can distinguish these cell lines by their growth characteristics in including morphology, migratory potential, and clonogenic potential...
October 2016: Biomedical Microdevices
Jen-Huang Huang, Jennifer F Harris, Pulak Nath, Rashi Iyer
This study demonstrates a rapid prototyping approach for fabricating and integrating porous hollow fibers (HFs) into microfluidic device. Integration of HF can enhance mass transfer and recapitulate tubular shapes for tissue-engineered environments. We demonstrate the integration of single or multiple HFs, which can give the users the flexibility to control the total surface area for tissue development. We also present three microfluidic designs to enable different co-culture conditions such as the ability to co-culture multiple cell types simultaneously on a flat and tubular surface, or inside the lumen of multiple HFs...
October 2016: Biomedical Microdevices
Brian J Kim, Willa Jin, Alexander Baldwin, Lawrence Yu, Eisha Christian, Mark D Krieger, J Gordon McComb, Ellis Meng
Neurosurgical ventricular shunts inserted to treat hydrocephalus experience a cumulative failure rate of 80 % over 12 years; obstruction is responsible for most failures with a majority occurring at the proximal catheter. Current diagnosis of shunt malfunction is imprecise and involves neuroimaging studies and shunt tapping, an invasive measurement of intracranial pressure and shunt patency. These patients often present emergently and a delay in care has dire consequences. A microelectromechanical systems (MEMS) patency sensor was developed to enable direct and quantitative tracking of shunt patency in order to detect proximal shunt occlusion prior to the development of clinical symptoms thereby avoiding delays in treatment...
October 2016: Biomedical Microdevices
Nobuyasu Hori, Miyuki Chikae, Hiroya Kirimura, Yuzuru Takamura
Electrochemical immunosensing, particularly through a metalloimmunoassay, is a promising approach for development of point-of-care (POC) diagnostics devices. This study investigated the structure of dual working electrodes (W1 and W2), used in a silver nanoparticles-labeled sandwich-type immunoassay and silver concentration process, paying special attention to the position of W1 relative to W2. The new structures of the dual working electrodes were fabricated for efficient silver concentration and evaluated experimentally, which showed that the duration of prereduction before current measurement decreased from 480 s to 300 s by transforming the position of W1 from 1 line to 2 lines or 6 parts...
October 2016: Biomedical Microdevices
Yen-Heng Lin, I-Chi Lee, Wei-Chieh Hsu, Ching-Hong Hsu, Kai-Ping Chang, Shao-Syuan Gao
The main issue of transdermal drug delivery is that macromolecular drugs cannot diffuse through the stratum corneum of skin. Many studies have pursued micro-sized needles encapsulated with drugs to overcome this problem, as these needles can pierce the stratum corneum and allow drugs to enter the circulatory system of the human body. However, most microneedle fabrication processes are time-consuming and require expensive equipment. In this study, we demonstrate a rapid method for fabricating a microneedle mold using drawing lithography and a UV-cured resin...
October 2016: Biomedical Microdevices
Chris S Ivanoff, Jie Jayne Wu, Hadi Mirzajani, Cheng Cheng, Quan Yuan, Stepan Kevorkyan, Radostina Gaydarova, Desislava Tomlekova
AC electrokinetics (ACEK) has been shown to deliver certain drugs into human teeth more effectively than diffusion. However, using electrical wires to power intraoral ACEK devices poses risks to patients. The study demonstrates a novel interdigitated electrode arrays (IDE) assembly powered by inductive coupling to induce ACEK effects at appropriate frequencies to motivate drugs wirelessly. A signal generator produces the modulating signal, which multiplies with the carrier signal to produce the amplitude modulated (AM) signal...
October 2016: Biomedical Microdevices
Nemanja Rajković, Daniela Kolarević, Ksenija Kanjer, Nebojša T Milošević, Dragica Nikolić-Vukosavljević, Marko Radulovic
Breast cancer prognosis is a subject undergoing intense study due to its high clinical relevance for effective therapeutic management and a great patient interest in disease progression. Prognostic value of fractal and gray level co-occurrence matrix texture analysis algorithms has been previously established on tumour histology images, but without any direct performance comparison. Therefore, this study was designed to compare the prognostic power of the monofractal, multifractal and co-occurrence algorithms on the same set of images...
October 2016: Biomedical Microdevices
Xiaoqiang Sun, Shujing Wang, Yue Yang, Chunxiong Luo, Benxiang Hou
Enterococcus faecalis (E. faecalis) is a species that has frequently been isolated from root canal of patients suffering from persistent periodontitis. To a great degree, the resistance of E. faecalis to irrigating solutions and intracanal medicaments is due to its invasion into the dentinal tubules. In this study, we developed a device to observe the dynamic process of the bacterial invasion into microtubes. According to the diameter of the dentinal tubules and other microstructures in the root canals, we designed four different size microtubes with different lengths in this device...
October 2016: Biomedical Microdevices
Christina Hassler, Julien Guy, Max Nietzschmann, Dennis T T Plachta, Jochen F Staiger, Thomas Stieglitz
Polyimide based shaft electrodes were coated with a bioresorbable layer to stiffen them for intracortical insertion and to reduce the mechanical mismatch between the target tissue and the implanted device after degradation of the coating. Molten saccharose was used as coating material. In a proof-of-concept study, the electrodes were implanted into the cortex of Wistar rats and the insertion forces during implantation were recorded. Electrochemical impedance spectroscopy was performed immediately after implantation and up to 13 weeks after implantation to monitor the tissue response to the implanted electrodes...
October 2016: Biomedical Microdevices
Yuan Xing, Mohammad Nourmohammadzadeh, Joshua E Mendoza Elias, Manwai Chan, Zequn Chen, James J McGarrigle, José Oberholzer, Yong Wang
We present a novel pumpless microfluidic array driven by surface tension for studying the physiology of pancreatic islets of Langerhans. Efficient fluid flow in the array is achieved by surface tension-generated pressure as a result of inlet and outlet size differences. Flow properties are characterized in numerical simulation and further confirmed by experimental measurements. Using this device, we perform a set of biological assays, which include real-time fluorescent imaging and insulin secretion kinetics for both mouse and human islets...
October 2016: Biomedical Microdevices
Hung-Wei Wu, Yao-Sheng Huang, Hsin-Ying Lee, Wu-Han Tsai, Kuan-Yu Chen, Li-Yi Jian
This article describes a high-efficiency light-induced dielectrophoresis biochip containing a thin film prepared through inductively coupled plasma chemical vapor deposition (ICPCVD). The biochip comprises two ITO glass substrates and a photoconductive amorphous silicon thin film. The biochip can effectively sort particular particles (or cells) by projecting visible light onto the surface of the silicon thin film. The sorting efficiency of biochips is highly associated with the quality of the deposited amorphous silicon thin films; therefore, the choice of deposition technique is extremely critical...
October 2016: Biomedical Microdevices
Daniel Lorusso, Hristo N Nikolov, Jaques S Milner, Noelle M Ochotny, Stephen M Sims, S Jeffrey Dixon, David W Holdsworth
We describe a simple fabrication technique - targeted towards non-specialists - that allows for the production of leak-proof polydimethylsiloxane (PDMS) microfluidic devices that are compatible with live-cell microscopy. Thin PDMS base membranes were spin-coated onto a glass-bottom cell culture dish and then partially cured via microwave irradiation. PDMS chips were generated using a replica molding technique, and then sealed to the PDMS base membrane by microwave irradiation. Once a mold was generated, devices could be rapidly fabricated within hours...
October 2016: Biomedical Microdevices
Jeff Darabi, Chuan Guo
Monocytes play an important role in the immune system and are responsible for phagocytizing and degrading foreign microorganisms in the body. The isolation of monocytes is important in various immunological applications such as in-vitro culture of dendritic cells. We present a magnetophoretic-based microfluidic chip for rapid isolation of highly purified, untouched monocytes from human blood by a negative selection method. This bioseparation platform integrates several unique features into a microfluidic device, including locally engineered magnetic field gradients and a continuous flow with a buffer switching scheme to improve the performance of the cell separation process...
October 2016: Biomedical Microdevices
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