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Desenvolvimento de sistemas Lab-on-a-Chip para análises em biofísica celular.; Development of Lab-On-Chip systems for biophysical analysis.

Lopera Aristizábal, Sergio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/03/2012 PT
Relevância na Pesquisa
105.91%
Este estudo tem por objetivo o desenvolvimento de uma metodologia de fabricação de sistemas Lab On Chip, úteis no estudo de processos celulares, a partir da adaptação de tecnologias próprias da microeletrônica. Foram exploradas todas as etapas envolvidas na fabricação de sistemas Lab On Chip em Poli-Di-Metil-Siloxano e desenvolvidos protocolos de fabricação de moldes, técnicas de moldagem e processos de ativação de PDMS com plasma de oxigênio para sua solda química sobre diferentes materiais, obtendo uniões irreversíveis que permitem a integração com outras tecnologias como a microeletrônica em silício e o encapsulamento com cerâmica verde, completando uma metodologia que permite a prototipagem de dispositivos micro-fluídicos de multicamadas com um nível de sofisticação comparável ao estado da arte. Foi desenvolvido o protótipo de um equipamento ótico para litografia por projeção que permite a fabricação de máscaras óticas com resolução de 5 m e oferece a possibilidade de litografia em escala de cinzas para gerar canais e estruturas com relevos arbitrários. Foram adicionalmente abordados três problemas de biofísica celular, para os quais foram propostos novos dispositivos para separação de células móveis de acordo às suas velocidades lineares...

Fabricação de microcanais para integração de uma língua eletrônica em um sistema lab-on-a-chip

Dantas, Cléber Aparecido Rocha
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: 60 f. : il.
POR
Relevância na Pesquisa
125.89%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Pós-graduação em Ciência e Tecnologia de Materiais - FC; Fabricamos neste trabalho microcanais em uma matriz de PDMS para otimização de uma configuração que permita, futuramente, a inserção de eletrodos interdigitados no interior dos mesmos para a integração da língua eletrônica que estamos trabalhando ao longo dos últimos anos com dispositivos lab-on-a-chip. O objetivo final é a fabricação de um sensor tongue-on-a-chip, não havendo nada similar na literatura até o presente momento, tendo-se em vista, principalmente, o potencial de aplicação de ambos dispositivos (língua eletrônica e lab-on-a-chip). Neste sentido, esta dissertação torna-se uma chave importante para o desenvolvimento de uma tecnologia nova e com forte apelo comercial. Como a fabricação dos microcanais envolve técnicas e equipamentos de litografia que não dispomos em nossos laboratórios, estendemos colaborações com o laboratório Nacional de Luz Síncroton (LNLS - através de um projeto específico nessa linha de atuação), onde fabricamos os microcanais e eletrodos interdigitados envolvidos neste trabalho. Como é a primeira vez que a microfluídica está sendo aplicada em dispositivos do tipo língua eletrônica...

Lab-on-a-chip for biological fluids analysis by spetrophotometry

Minas, Graça; Wolffenbuttel, R. F.; Correia, J. H.
Fonte: Chatila Publishing House Publicador: Chatila Publishing House
Tipo: Artigo de Revista Científica
Publicado em //2006 ENG
Relevância na Pesquisa
125.74%
The healthcare sector is nowadays one of the most dynamic and where the novelty is a strategic and operational imperative. The possibility of increase the quantity and quality of clinical analysis, performed with instantaneous results and outside the clinical laboratories, contributes to a better quality in the health care services and also a better efficiency in the clinical and administrative processes [1]. This possibility can be achieved with the presented lab-on-a-chip for spectrophotometric analysis of biological fluids. It allows the selective measurement of the concentration of several biomolecules in biological fluids, with instantaneous results, at any location, with small quantities of reagents and samples and with low-cost. That measurement is based on colorimetric detection by the optical absorption in a part of the visible spectrum defined by the reaction of the specific biomolecule with a specific reagent. The device comprises a highly efficient and selective optical filtering and colorimetric detection system. This system allows the measurement with a regular white light illumination, thus avoiding the use of complex and expensive analysis systems like the ones that comprise spectrophotometers, for example. This feature highly facilitates portability and ensures analysis within consultation time...

Design of a lab-on-a-chip for clinical tests of human physiological fluids

Miranda, J. M.; Minas, Graça; Vicente, A. A.; Teixeira, J. A.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2006 ENG
Relevância na Pesquisa
95.86%
Labs-on-a-chip are useful to perform in situ clinical tests with instantaneous results. In this work, the design phase of the development of a lab-on-a-chip is presented. The device will be used to perform tests on physiological fluids. It will be able to test 8 components: calcium, chloride, creatinine, glucose, magnesium, total protein, urea and uric acid. A sample of the physiological fluid reacts with several reagents and the device measures the absorbance of the reaction products. The lab-on-a-chip is composed of a microfluidic system and an optical detection system. The first contains microchannels and micro-reactors fabricated using SU-8 techniques. The second includes CMOS photodetectors and readout electronics, as well as optical filters fabricated using CMOS-compatible post-processing on top of the photodetectors. Careful design of the microfluidic system of a lab-on-a-chip requires knowledge of the transport phenomena in the microchannels. Numerical methods are used to simulate the electroosmotic flow, reaction and mixture in the system. Velocitypressure formulation of the Navier-Stokes equations is solved by a finite difference method. Mass transport equation is solved by a second order finite difference method. For enzymatic reactions...

Investigation of T Shape geometry for the collectıon of pollutıon partıcles

Mercimek, M.; Yıldırım, H.; Miguel, A. F.; Aydin, M.
Fonte: GCGW Publicador: GCGW
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
95.65%
The study of suspension flow is of considerable importance in many fields of science and technology. Particle pollution, for example, has become a main issue of our days due to harmful aspects associated. For rational air pollution, sampling devices are essential. In this work, we numerically investigate a three dimensional T-shaped device that can be used for aerosol sampling or Lab-On-a-Chip (LOC) devices. Two key quantities are used to characterize the suspension flow: Particle deposition and residence time distribution of the particles. This study clearly demonstrates that the geometric characteristics of T-shaped structure and the Reynolds number should be closely controlled in order to obtain the required particle deposition and dispersion of particles inside the T-shaped structure.

Phytogeographical origin of Madeiran common beans based on phaseolin patterns

Silva,Emanuel Marques da; Correia,Anísia Soraia Abreu; Lopes,Nuno Alexandre Amaral; Nóbrega,Humberto Gil Moreira; Ganança,José Filipe Teixeira; Domingues,Ana Maria; Khadem,Manhaz; Slaski,Jan Jacek; Carvalho,Miguel Ângelo Almeida Pinheiro de
Fonte: Embrapa Informação Tecnológica; Pesquisa Agropecuária Brasileira Publicador: Embrapa Informação Tecnológica; Pesquisa Agropecuária Brasileira
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2010 EN
Relevância na Pesquisa
95.66%
The objective of this work was to determine the geographic origin of the Madeiran common bean (Phaseolus vulgaris) gene pool. Phaseolin patterns of 50 accessions representing the diversity of common bean collected in Madeira, Portugal, and conserved in the ISOPlexis Germplasm Bank, were analysed using the Experion automated electrophoresis system, based on lab-on-a-chip technology. Five common bean standard varieties with typical phaseolin patterns were used to determine the phytogeographical origin of the Madeiran common bean accessions. Ninety two percent of the accessions exhibited a phaseolin pattern consistent with the one of common bean types belonging to the Andean gene pool, while the origin of the remaining 8% of the accessions was indistinguishable. The application of a similarity coefficient of 85%, based on Pearson correlations, increases the number of accessions with uncertain pattern. The analytical approach used permitted the determination of the origin of the common bean gene pool, which is Andean in 98% of the cases, and clustering of the observed variability among the Madeiran common beans.

Manufacturing of miniature fluidic modules for lab-on-a-chip using UA photoresin from flexographic platemaking process

Fernandes,Julio Cesar B.; Ferreira,Luiz Otávio S.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2006 EN
Relevância na Pesquisa
95.66%
A new technique of fabrication of miniaturized fluidic devices was developed using a photoresin based on urethane and acrylate (UA) oligomers used to platemaking for flexographic printers on graphic industry. Fluidic mixers and reactors modules measuring 10×10 mm² were manufactured, with channels width in the 0.25 to 1.00 mm range and 0.75 mm depth. Top covers 4.00 mm thick, with 1.26 mm diameter inlet and outlet holes were used to seal the channels. The sealed channel structures were formed using a film of photoresin as adhesive. Interconnections of 1.20 mm diameter and 10 mm long steel tubes were fixed into inlet and outlet holes. All fluidic modules were manufactured by photolithography of UA, sealed by ultraviolet cure of an UA adhesion layer, package in an UA container and successfully tested for leakage under 2×10(5) Pascal air pressure.

Lab-on-a-Chip Pathogen Sensors for Food Safety

Yoon, Jeong-Yeol; Kim, Bumsang
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 06/08/2012 EN
Relevância na Pesquisa
85.87%
There have been a number of cases of foodborne illness among humans that are caused by pathogens such as Escherichia coli O157:H7, Salmonella typhimurium, etc. The current practices to detect such pathogenic agents are cell culturing, immunoassays, or polymerase chain reactions (PCRs). These methods are essentially laboratory-based methods that are not at all real-time and thus unavailable for early-monitoring of such pathogens. They are also very difficult to implement in the field. Lab-on-a-chip biosensors, however, have a strong potential to be used in the field since they can be miniaturized and automated; they are also potentially fast and very sensitive. These lab-on-a-chip biosensors can detect pathogens in farms, packaging/processing facilities, delivery/distribution systems, and at the consumer level. There are still several issues to be resolved before applying these lab-on-a-chip sensors to field applications, including the pre-treatment of a sample, proper storage of reagents, full integration into a battery-powered system, and demonstration of very high sensitivity, which are addressed in this review article. Several different types of lab-on-a-chip biosensors, including immunoassay- and PCR-based, have been developed and tested for detecting foodborne pathogens. Their assay performance...

Lab-on-a-chip sensor for detection of highly electronegative heavy metals by anodic stripping voltammetry

Jothimuthu, Preetha; Wilson, Robert A.; Herren, Josi; Haynes, Erin N.; Heineman, William R.; Papautsky, Ian
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/2011 EN
Relevância na Pesquisa
95.8%
This work describes development of a lab-on-a-chip sensor for electrochemical detection of highly electro-negative heavy metals such as manganese and zinc by anodic stripping voltammetry. The sensor consists of a three-electrode system, with a bismuth working electrode, a Ag/AgCl reference electrode, and a Au auxiliary electrode. Hydrolysis at the auxiliary electrode is a critical challenge in such electrochemical sensors as its onset severely limits the ability to detect electronegative metals. The bismuth working electrode is used due to its comparable negative detection window and reduced toxicity with respect to a conventional mercury electrode. Through optimization of the sensor layout and the working electrode surface, effects of hydrolysis were substantially reduced and the potential window was extended to the −0.3 to −1.9 V range (vs. Ag/AgCl reference electrode), which is far more negative than what is possible with conventional Au, Pt, or carbon electrodes. The described lab-on-a-chip sensor for the first time permits reliable and sensitive detection of the highly electronegative manganese. The favorable performance of the bismuth electrode coupled with its environmentally-friendly nature make the described sensor attractive for applications where disposable chips are desirable. With further development and integrated sample preparation...

Lab-on-a-chip technologies for single-molecule studies

Zhao, Yanhui; Chen, Danqi; Yue, Hongjun; French, Jarrod B.; Rufo, Joey; Benkovic, Stephen J.; Huang, Tony Jun
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
85.87%
Recent developments on various lab-on-a-chip techniques allow miniaturized and integrated devices to perform on-chip single-molecule studies. Fluidic-based platforms that utilize the unique microscale fluidic behavior are capable of conducting single-molecule experiments with high sensitivities and throughputs, while biomolecular systems can be studied on-chip using techniques such as DNA curtains, magnetic tweezers, and solid-state nanopores. The advances of these on-chip single-molecule techniques lead to next-generation lab-on-a-chip devices such as DNA transistors, and single-molecule real-time (SMRT) technology for rapid and low-cost whole genome DNA sequencing. In this Focus article, we will discuss some recent successes on developing lab-on-a-chip techniques for single-molecule studies and expound our thoughts on the near future of on-chip single-molecule studies.

A lab-on-a-chip for hypoxic patch clamp measurements combined with optical tweezers and spectroscopy- first investigations of single biological cells

Alrifaiy, Ahmed; Borg, Johan; Lindahl, Olof A; Ramser, Kerstin
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 18/04/2015 EN
Relevância na Pesquisa
95.7%
The response and the reaction of the brain system to hypoxia is a vital research subject that requires special instrumentation. With this research subject in focus, a new multifunctional lab-on-a-chip (LOC) system with control over the oxygen content for studies on biological cells was developed. The chip was designed to incorporate the patch clamp technique, optical tweezers and absorption spectroscopy. The performance of the LOC was tested by a series of experiments. The oxygen content within the channels of the LOC was monitored by an oxygen sensor and verified by simultaneously studying the oxygenation state of chicken red blood cells (RBCs) with absorption spectra. The chicken RBCs were manipulated optically and steered in three dimensions towards a patch-clamp micropipette in a closed microfluidic channel. The oxygen level within the channels could be changed from a normoxic value of 18% O 2 to an anoxic value of 0.0-0.5% O 2. A time series of 3 experiments were performed, showing that the spectral transfer from the oxygenated to the deoxygenated state occurred after about 227 ± 1 s and a fully developed deoxygenated spectrum was observed after 298 ± 1 s, a mean value of 3 experiments. The tightness of the chamber to oxygen diffusion was verified by stopping the flow into the channel system while continuously recording absorption spectra showing an unchanged deoxygenated state during 5400 ± 2 s. A transfer of the oxygenated absorption spectra was achieved after 426 ± 1 s when exposing the cell to normoxic buffer. This showed the long time viability of the investigated cells. Successful patching and sealing were established on a trapped RBC and the whole-cell access (Ra) and membrane (Rm) resistances were measured to be 5.033 ± 0.412 M Ω and 889.7 ± 1.74 M Ω respectively.

Lab-on-a-Chip Magneto-Immunoassays: How to Ensure Contact between Superparamagnetic Beads and the Sensor Surface

Eickenberg, Bernhard; Meyer, Judith; Helmich, Lars; Kappe, Daniel; Auge, Alexander; Weddemann, Alexander; Wittbracht, Frank; Hütten, Andreas
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
125.78%
Lab-on-a-chip immuno assays utilizing superparamagnetic beads as labels suffer from the fact that the majority of beads pass the sensing area without contacting the sensor surface. Different solutions, employing magnetic forces, ultrasonic standing waves, or hydrodynamic effects have been found over the past decades. The first category uses magnetic forces, created by on-chip conducting lines to attract beads towards the sensor surface. Modifications of the magnetic landscape allow for additional transport and separation of different bead species. The hydrodynamic approach uses changes in the channel geometry to enhance the capture volume. In acoustofluidics, ultrasonic standing waves force µm-sized particles onto a surface through radiation forces. As these approaches have their disadvantages, a new sensor concept that circumvents these problems is suggested. This concept is based on the granular giant magnetoresistance (GMR) effect that can be found in gels containing magnetic nanoparticles. The proposed design could be realized in the shape of paper-based test strips printed with gel-based GMR sensors.

Phytogeographical origin of Madeiran common beans based on phaseolin patterns.

SILVA, E. M. da; CORREIA, A. S. A.; LOPES, N. A. A.; NOBREGA, H. G. M.; GANANÇA, J. F. T.; DOMINGUES, A. M.; KHADEM, M.; SLASKI, J. J.; CARVALHO, M. A. A. P. de
Fonte: Pesquisa Agropecuaria brasileira., Brasília, v.45, n.8, p.863-871, ago. 2010 Publicador: Pesquisa Agropecuaria brasileira., Brasília, v.45, n.8, p.863-871, ago. 2010
Tipo: Artigo em periódico indexado (ALICE)
EN
Relevância na Pesquisa
105.65%
Abstract ? The objective of this work was to determine the geographic origin of the Madeiran common bean (Phaseolus vulgaris) gene pool. Phaseolin patterns of 50 accessions representing the diversity of common bean collected in Madeira, Portugal, and conserved in the ISOPlexis Germplasm Bank, were analysed using the Experion automated electrophoresis system, based on lab-on-a-chip technology. Five common bean standard varieties with typical phaseolin patterns were used to determine the phytogeographical origin of the Madeiran common bean accessions. Ninety two percent of the accessions exhibited a phaseolin pattern consistent with the one of common bean types belonging to the Andean gene pool, while the origin of the remaining 8% of the accessions was indistinguishable. The application of a similarity coefficient of 85%, based on Pearson correlations, increases the number of accessions with uncertain pattern. The analytical approach used permitted the determination of the origin of the common bean gene pool, which is Andean in 98% of the cases, and clustering of the observed variability among the Madeiran common beans.; 2010

Utilização da tecnologia LAB-ON-A-CHIP para detecção de Ehrlichia canis por pcr em amostras de sangue de cães experimentalmente infectados.

BRITO, L. G.; TERRA, V. J. B.; HUACCA, M. E. F.; OLIVEIRA, M. C. de S.; PEREIRA, A. N.; REGITANO, L. C. de A.; LEMOS E. R. S.
Fonte: In: CONGRESSO BRASILEIRO DE PARASITOLOGIA VETERINÁRIA, 13.; SIMPÓSIO LATINO-AMERICANO DE RICKETTSIOSES, 2004, Ouro Preto, MG. Anais... Ouro Preto: SBPV, 2004. Publicador: In: CONGRESSO BRASILEIRO DE PARASITOLOGIA VETERINÁRIA, 13.; SIMPÓSIO LATINO-AMERICANO DE RICKETTSIOSES, 2004, Ouro Preto, MG. Anais... Ouro Preto: SBPV, 2004.
Tipo: Resumo em anais de congresso (ALICE) Formato: p.356.
EN
Relevância na Pesquisa
95.65%
2004

Análise proteômica do soro sanguíneo de ratos adultos submetidos à desnutrição neonatal

de Andrade Bezerra, Alice; Luiz de Lima Filho, José (Orientador)
Fonte: Universidade Federal de Pernambuco Publicador: Universidade Federal de Pernambuco
Tipo: Outros
PT_BR
Relevância na Pesquisa
95.64%
Estímulos atuantes durante períodos fetal e neonatal desencadeiam modificações fisiológicas e metabólicas permanentes no indivíduo, fenômeno bastante estudado em Nutrição através de manipulação nutricional. Para pesquisa de alterações biomoleculares, o soro sanguíneo é fonte potencial de biomarcadores protéicos. Este estudo teve como objetivo avaliar os efeitos da desnutrição protéica neonatal sobre o perfil proteômico do soro sanguíneo de ratos adultos. Foram utilizados 8 ratos Wistar, machos, adultos, que foram divididos em 2 grupos, de acordo com a dieta disponibilizada do 1º ao 21º dia de vida (período de lactação): grupo nutrido (GN), formado por filhotes cujas mães receberam dieta com 17 % de caseína e grupo desnutrido (GD), no qual as mães alimentaram-se de dieta com 8 % de caseína. No período de reposição nutricional, a partir do desmame (22º dia), os filhotes passaram a receber dieta padrão normoprotéica. Os animais foram pesados diariamente durante aleitamento e, posteriormente, em dias alternados. Na idade adulta, a partir do 90º dia de vida, os animais foram anestesiados e submetidos à punção cardíaca para coleta de sangue (4mL). Após coagulação, este foi centrifugado, a camada de soro coletada e acondicionada a -20ºC. Alíquotas foram inicialmente diluídas (1:10) para análise eletroforética monodimensional pela tecnologia lab-on-a-chip...

Digital Surveillance Based on Video CODEC System-on-a-Chip (SoC) Platforms

Zhao, Wei
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
95.62%
Today, most conventional surveillance networks are based on analog system, which has a lot of constraints like manpower and high-bandwidth requirements. It becomes the barrier for today’s surveillance network development. This dissertation describes a digital surveillance network architecture based on the H.264 coding/decoding (CODEC) System-on-a-Chip (SoC) platform. The proposed digital surveillance network architecture includes three major layers: software layer, hardware layer, and the network layer. The following outlines the contributions to the proposed digital surveillance network architecture. (1) We implement an object recognition system and an object categorization system on the software layer by applying several Digital Image Processing (DIP) algorithms. (2) For better compression ratio and higher video quality transfer, we implement two new modules on the hardware layer of the H.264 CODEC core, i.e., the background elimination module and the Directional Discrete Cosine Transform (DDCT) module. (3) Furthermore, we introduce a Digital Signal Processor (DSP) sub-system on the main bus of H.264 SoC platforms as the major hardware support system for our software architecture. Thus we combine the software and hardware platforms to be an intelligent surveillance node. Lab results show that the proposed surveillance node can dramatically save the network resources like bandwidth and storage capacity.

A flexible lab-on-a-chip for the synthesis and magnetic separation of magnetite decorated with gold nanoparticles

Cabrera, Flavio C.; Melo, Antonio F. A. A.; Souza, Joao C. P. de; Job, Aldo E.; Crespilho, Frank N.
Fonte: Royal Soc Chemistry Publicador: Royal Soc Chemistry
Tipo: Artigo de Revista Científica Formato: 1835-1841
ENG
Relevância na Pesquisa
95.74%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Processo FAPESP: 2013/14262-7; Processo FAPESP: 2013/04663-4; Processo FAPESP: 2011/23362-0; Magnetite decorated with gold nanoparticles (Fe3O4-AuNPs) is a ferrimagnetic material with unprecedented applications in immunosensors, as a contrast agent for imaging diagnosis, and for the photothermal ablation of tumor cells. Here, we show the preparation of controlled amounts of Fe3O4-AuNPs without organic solvents, surfactants, or heat treatment. For this, we have developed a customized natural-rubber-based microfluidic device (NRMD) as a flexible lab-on-a-chip for the decoration of Fe3O4 with AuNPs. With a novel NRMD configuration, monodisperse Fe3O4-NPs (phi = 10 nm) decorated with AuNPs (phi = 4 nm) were readily obtained. The AuNPs were homogenous in terms of their size and their distribution on the Fe3O4-NP surfaces. Furthermore, the lab-on-a-chip was projected with an internal system for magnetic separation, an innovation in terms of aqueous/carrier phase separation. Finally, the nanomaterials produced with this NRMD are free of organic solvents and surfactants...

Bone Marrow–on–a–Chip Replicates Hematopoietic Niche Physiology in Vitro

Torisawa, Yu-suke; Spina, Catherine; Mammoto, Tadanori; Mammoto, Akiko; Weaver, James C.; Tat, Tracy; Collins, James J.; Ingber, Donald Elliot
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
95.56%
Current in vitro hematopoiesis models fail to demonstrate the cellular diversity and complex functions of living bone marrow; hence, most translational studies relevant to the hematologic system are conducted in live animals. Here we describe a method for fabricating 'bone marrow–on–a–chip' that permits culture of living marrow with a functional hematopoietic niche in vitro by first engineering new bone in vivo, removing it whole and perfusing it with culture medium in a microfluidic device. The engineered bone marrow (eBM) retains hematopoietic stem and progenitor cells in normal in vivo–like proportions for at least 1 week in culture. eBM models organ-level marrow toxicity responses and protective effects of radiation countermeasure drugs, whereas conventional bone marrow culture methods do not. This biomimetic microdevice offers a new approach for analysis of drug responses and toxicities in bone marrow as well as for study of hematopoiesis and hematologic diseases in vitro.; Engineering and Applied Sciences

Liquid-infiltrated photonic crystals - enhanced light-matter interactions for lab-on-a-chip applications

Mortensen, Niels Asger; Xiao, Sanshui; Pedersen, Jesper
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/07/2007
Relevância na Pesquisa
85.81%
Optical techniques are finding widespread use in analytical chemistry for chemical and bio-chemical analysis. During the past decade, there has been an increasing emphasis on miniaturization of chemical analysis systems and naturally this has stimulated a large effort in integrating microfluidics and optics in lab-on-a-chip microsystems. This development is partly defining the emerging field of optofluidics. Scaling analysis and experiments have demonstrated the advantage of micro-scale devices over their macroscopic counterparts for a number of chemical applications. However, from an optical point of view, miniaturized devices suffer dramatically from the reduced optical path compared to macroscale experiments, e.g. in a cuvette. Obviously, the reduced optical path complicates the application of optical techniques in lab-on-a-chip systems. In this paper we theoretically discuss how a strongly dispersive photonic crystal environment may be used to enhance the light-matter interactions, thus potentially compensating for the reduced optical path in lab-on-a-chip systems. Combining electromagnetic perturbation theory with full-wave electromagnetic simulations we address the prospects for achieving slow-light enhancement of Beer-Lambert-Bouguer absorption...

Modeling, Fabrication, and Test of a CMOS Integrated Circuit Platform for Electrophoretic Control of On-Chip Heterogeneous Fluids: toward Particle Separation on a Custom CMOS Chip

Wake, Heather Anne
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 91145523 bytes; application/pdf
Publicado em //2009 EN_US
Relevância na Pesquisa
95.67%

Electrophoresis is the migration of charged particles in a heterogeneous fluid under the influence of an electric field. This project is work toward an electrophoretic separation system on a custom CMOS chip. Modeling, fabrication, and testing of an AMI ABN 1.5 um CMOS chip for this application is discussed. The unique approach is to build the entire system using conventional CMOS integrated circuit technology, such that the separation area is fabricated on the chip with integrated control and detection circuitry. To achieve the desired functionality, a novel configuration of an electrophoresis system is implemented. In this system, instead of using only one electrode at each end of the separation area, a multitude of electrodes beneath the entire separation area are utilized, enabling better control of high electric fields using very small voltages over small areas. Electronic circuits control the position and strength of the electric field to drive the separations and to simultaneously detect the location and concentration of samples within the separation area. Ultimately, the project was successful at showing that implementing an electrophoresis system on standard CMOS is possible.

; Dissertation