Biomedical subjects

Anne M Taylor

Publications and source records attributed to Anne M Taylor.

5 recordsLinked to original sources

PubMed2007

External force-assisted cell positioning inside microfluidic devices.

This paper describes straightforward approaches to positioning cells within microfluidic devices that can be implemented without special equipment or fabrication steps. External forces can effectively transport and position cells in preferred locations inside microfluidic channels. Except for centrifugal force-based positioning that can be used with any microfluidic channels, hydrodynamic and gravitational force-based positioning yield reproducible and biocompatible results when implemented with a microfluidic "module" that contains a barrier with embedded microgrooves. Primary rat cortical neurons, metastatic human breast cancer cells MDA-MB-231, NIH 3T3 mouse fibroblasts, and human umbilical vein endothelial cells (HUVECs) were compatible with the positioning processes. After positioning, cells attached, proliferated and migrated like control cells that were cultured on tissue culture dishes or glass coverslips. No apparent morphological differences were observed in positioned cells compared with control cells. Finally, to demonstrate a practical application of the methods, cells were placed in a single row along a wall inside a microfluidic chemotaxis chamber (MCC), and were exposed to stable concentration gradient of chemoattractant. Cell positioning allows that all cells get exposed to the same level of chemoattractant at the start of the experiment helping standardize cellular response.

Animals↗

PubMed2006

Microfluidic chambers for cell migration and neuroscience research.

This chapter describes the fabrication and use microfluidic chambers for cell migration and neuroscience research. Both microfluidic chambers are made using soft lithography and replica molding. The main advantages of using soft lithography to create microfluidic chambers are reproducibility, ease of use, and straightforward fabrication procedures. The devices can be fabricated in biology and chemistry laboratories with minimal access to clean-room facilities. First, a microfluidic chemotaxis chamber, which has been used in investigating chemotaxis of neutrophils, human breast cancer cells, and other cell types, is described. Precise and stable gradients of chemoattractants with arbitrary shapes can be generated for different applications. Second, a multicompartment culture chamber that can fluidically isolate neuronal processes from cell bodies is described. The design of this chamber is such that only neurites grow through a series of microgrooves embedded in a physical barrier. Both devices are compatible with phase, differential interference contrast, and fluorescence microscopy.

Animals↗

PubMed2005

A microfluidic culture platform for CNS axonal injury, regeneration and transport.

Investigation of axonal biology in the central nervous system (CNS) is hindered by a lack of an appropriate in vitro method to probe axons independently from cell bodies. Here we describe a microfluidic culture platform that polarizes the growth of CNS axons into a fluidically isolated environment without the use of targeting neurotrophins. In addition to its compatibility with live cell imaging, the platform can be used to (i) isolate CNS axons without somata or dendrites, facilitating biochemical analyses of pure axonal fractions and (ii) localize physical and chemical treatments to axons or somata. We report the first evidence that presynaptic (Syp) but not postsynaptic (Camk2a) mRNA is localized to developing rat cortical and hippocampal axons. The platform also serves as a straightforward, reproducible method to model CNS axonal injury and regeneration. The results presented here demonstrate several experimental paradigms using the microfluidic platform, which can greatly facilitate future studies in axonal biology.

Animals↗

PubMed2004

Patterned cell culture inside microfluidic devices.

This paper describes a simple plasma-based dry etching method that enables patterned cell culture inside microfluidic devices by allowing patterning, fluidic bonding and sterilization steps to be carried out in a single step. This plasma-based dry etching method was used to pattern cell-adhesive and non-adhesive areas on the glass and polystyrene substrates. The patterned substrate was used for selective attachment and growth of human umbilical vein endothelial cells, MDA-MB-231 human breast cancer cells, NIH 3T3 mouse fibroblasts, and primary rat cortical neurons. Finally, we have successfully combined the dry-patterned substrate with a microfluidic device. Patterned primary rat neurons were maintained for up to 6 days inside the microfluidic devices and the neurons' somas and processes were confined to the cell-adhesive region. The method developed in this work offers a convenient way of micropatterning biomaterials for selective attachment of cells on the substrates, and enables culturing of patterned cells inside microfluidic devices for a number of biological research applications where cells need to be exposed to well-controlled fluidic microenvironment.

Animals↗

PubMed2002

Identification of P2Y12-dependent and -independent mechanisms of glycoprotein VI-mediated Rap1 activation in platelets.

Glycoprotein (GP) VI is a critical platelet collagen receptor, yet the steps involved in GPVI-mediated platelet activation remain incompletely understood. Because activation of Rap1, an abundant small guanosine triphosphatase (GTPase) in platelets, contributes to integrin alpha(IIb)beta(3) activation, we asked whether and how GPVI signaling activates Rap1 in platelets. Here we show that platelet Rap1 is robustly activated upon addition of convulxin, a GPVI-specific agonist. Using a reconstituted system in RBL-2H3 cells, we found that GPVI-mediated Rap1 activation is dependent on FcRgamma but independent of another platelet collagen receptor, alpha(2)beta(1). Interestingly, GPVI-mediated Rap1 activation in human platelets is largely dependent on adenosine diphosphate (ADP) signaling through the P2Y(12) and not the P2Y(1) receptor. However, experiments with specific ADP receptor antagonists and platelets from knockout mice deficient in P2Y(1) or the P2Y(12)-associated G-protein, Galphai(2), indicate that human and murine platelets also have a significant P2Y(12)-independent component of GPVI-mediated Rap1 activation. The P2Y(12)-independent component is dependent on phosphatidylinositol 3-kinase and is augmented by epinephrine-mediated signaling. P2Y(12)-dependent and -independent components are also observed in GPVI-mediated platelet aggregation, further supporting a role for Rap1 in aggregation. These results define mechanisms of GPVI-mediated platelet activation and implicate Rap1 as a key signaling protein in GPVI-induced platelet signaling.

Adenosine Diphosphate↗