Micro- and Nanotechnologies for Studying Cellular Function

Shim, Jeongsup; Bersano-Begey, Tommaso; Zhu, Xiaoyue; Tkaczyk, Alan H.; Linderman, Jennifer J.; Takayama, Shuichi

doi:10.2174/1568026033452393

Cited by 44 publications

(28 citation statements)

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“…Microfluidic devices were fabricated using standard soft lithography methods (30,35,38) . Approximately 2 ml of selected negative-tone photoresist (SU-8, MicroChem, Newton, MA) was dispensed onto the wafer on a spinner.…”

Section: Vol 71 2005 Mobility Of Protozoa Through Narrow Channels 4629mentioning

confidence: 99%

Mobility of Protozoa through Narrow Channels

Wang¹,

Shor²,

LeBoeuf³

et al. 2005

Appl Environ Microbiol

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Microbes in the environment are profoundly affected by chemical and physical heterogeneities occurring on a spatial scale of millimeters to micrometers. Physical refuges are critical for maintaining stable bacterial populations in the presence of high predation pressure by protozoa. The effects of microscale heterogeneity, however, are difficult to replicate and observe using conventional experimental techniques. The objective of this research was to investigate the effect of spatial constraints on the mobility of six species of marine protozoa. Microfluidic devices were created with small channels similar in size to pore spaces in soil or sediment systems. Individuals from each species of protozoa tested were able to rapidly discover and move within these channels. The time required for locating the channel entrance from the source well increased with protozoan size and decreased with channel height. Protozoa of every species were able to pass constrictions with dimensions equal to or smaller than the individual's unconstrained cross-sectional area. Channel geometry was also an important factor affecting protozoan mobility. Linear rates of motion for various species of protozoa varied by channel size. In relatively wide channels, typical rates of motion were 300 to 500 m s ؊1 (or about 1 m per hour). As the channel dimensions decreased, however, motilities slowed more than an order of magnitude to 20 m s ؊1 . Protozoa were consistently observed to exhibit several strategies for successfully traversing channel reductions. The empirical results and qualitative observations resulting from this research help define the physical limitations on protozoan grazing, a critical process affecting microbes in the environment.

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Section: Vol 71 2005 Mobility Of Protozoa Through Narrow Channels 4629mentioning

confidence: 99%

Mobility of Protozoa through Narrow Channels

Wang¹,

Shor²,

LeBoeuf³

et al. 2005

Appl Environ Microbiol

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“…To record metabolic changes of a small number or single cells it is necessary to scale down the cell culture volume and the sensor size and provide fluidic access to the cell culture volume for perfusion and toxin delivery (Shim et al, 2003). Recently, microfabrication and microfluidic technologies have been utilized to develop lab-on-a-chip devices for cell analysis in which the extracellular volume and the sensor size is smaller than or comparable to the cell size approaching in vivo conditions (Cheng et al, 2006;Ganitkevich et al, 2006b).…”

Section: Introductionmentioning

confidence: 99%

On-chip acidification rate measurements from single cardiac cells confined in sub-nanoliter volumes

Ges

Dzhura

Baudenbacher

2008

Biomed Microdevices

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The metabolic activity of cells can be monitored by measuring the pH in the extracellular environment. Microfabrication and microfluidic technologies allow the sensor size and the extracellular volumes to be comparable to single cells. A glass substrate with thin film pH sensitive IrO x electrodes was sealed to a replica-molded polydimethylsiloxane (PDMS) microfluidic network with integrated valves. The device, termed NanoPhysiometer, allows the trapping of single cardiac myocytes and the measurement of the pH in a detection volume of 0.36 nL. For wild-type (WT) single cardiac myocytes an acidification rate of 6.45 ± 0.38 mpH/min was measured in comparison to 19.5 ± 0.38 mpH/min for very long chain Acyl-CoA dehydrogenase (VLCAD) deficient mice in 0.8 mM of Ca 2+ . VLCAD deficiency is a fatty acid oxidation disease leading to cardiomyopathy and arrhythmias. The acidification rate increased to 11.96 ± 1.33 mpH/min for WT and to 32.0 ± 4.64 mpH/min for VLCAD −/− in 1.8 mM of Ca 2+ . The NanoPhysiometer concept can be extended to study ischemia/reperfusion injury or disorders of other biological systems to identify strategies for treatment and possible pharmacological targets.

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“…Such differences will be advantageous for enhanced autocrine and paracrine effects, for example, and are expected to affect cell function. [2,3,44] …”

Section: Full Papermentioning

confidence: 99%

“…These components present the cells with biochemical signals, and the cells are continually faced with sensing these inputs, processing the signals through signal transduction and gene regulation networks, and executing cell behavioral or fate choices. [1,2] Two of the most important microenvironment components are oxygen concentrations and the extracellular matrix (ECM). Recently, we demonstrated that oxygen concentrations can be regulated in microfluidic bioreactors made of poly(dimethylsiloxane) (PDMS).…”

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte‐Clay‐Protein Layer Films on Microfluidic PDMS Bioreactor Surfaces for Primary Murine Bone Marrow Culture

Mehta

Kiel

Lee

et al. 2007

Adv Funct Materials

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Poly(dimethylsiloxane) (PDMS) microbioreactors with computerized perfusion controls would be useful for engineering the bone marrow microenvironment. However, previous efforts to grow primary bone marrow cells on PDMS substrates have not been successful due to the weak attachment of cells to the PDMS surface even with adsorption of cell adhesive proteins such as collagen or fibronectin. In this work, modification of the surface of PDMS with biofunctional multilayer coatings is shown to promote marrow cell attachment and spreading. An automated microfluidic perfusion system is used to create multiple types of polyelectrolyte nanoscale coatings simultaneously in multiple channels based on layer‐by‐layer deposition of PDDA (poly(diallyldimethyl ammonium chloride)), clay, type IV collagen and fibronectin. Adherent primary bone marrow cells attached and spread best on a surface with composition of (PDDA/clay)5 (Collagen/Fibronectin)2 with negatively charged fibronectin exposed on the top, remaining well spread and proliferating for at least two weeks. Compared to traditional more macroscopic layer‐by‐layer methods, this microfluidic nanocomposite process has advantages of greater flow control, automatic processing, multiplexed fabrication, and use of lesser amounts of polymers and protein solutions.

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Micro- and Nanotechnologies for Studying Cellular Function

Cited by 44 publications

References 0 publications

Mobility of Protozoa through Narrow Channels

Mobility of Protozoa through Narrow Channels

On-chip acidification rate measurements from single cardiac cells confined in sub-nanoliter volumes

Polyelectrolyte‐Clay‐Protein Layer Films on Microfluidic PDMS Bioreactor Surfaces for Primary Murine Bone Marrow Culture

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