A fabrication technology for three-dimensional micro total analysis systems

Zellner, Phillip; Renaghan, Liam; Hasnain, Zaki; Agah, Masoud

doi:10.1088/0960-1317/20/4/045013

Cited by 30 publications

(15 citation statements)

References 29 publications

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“…Recent reports have shown that it is possible to generate isotropic microstructures comprised of curved surfaces by varying the geometrical patterns of the mask layout and using DRIE. This fabrication approach, which is used to etch silicon to different depths using a single-etch step process, is based on the applicability of RIE lag and its dependence on the geometrical patterns of the mask layout [49,50]. …”

Section: Fabrication Techniquesmentioning

confidence: 99%

Engineering microscale topographies to control the cell–substrate interface

et al. 2012

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Cells in their in vivo microenvironment constantly encounter and respond to a multitude of signals. While the role of biochemical signals has long been appreciated, the importance of biophysical signals has only recently been investigated. Biophysical cues are presented in different forms including topography and mechanical stiffness imparted by the extracellular matrix and adjoining cells. Microfabrication technologies have allowed for the generation of biomaterials with microscale topographies to study the effect of biophysical cues on cellular function at the cell–substrate interface. Topographies of different geometries and with varying microscale dimensions have been used to better understand cell adhesion, migration, and differentiation at the cellular and sub-cellular scales. Furthermore, quantification of cell-generated forces has been illustrated with micropillar topographies to shed light on the process of mechanotransduction. In this review, we highlight recent advances made in these areas and how they have been utilized for neural, cardiac, and musculoskeletal tissue engineering application.

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Section: Fabrication Techniquesmentioning

confidence: 99%

Engineering microscale topographies to control the cell–substrate interface

et al. 2012

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“…The fabrication process flow from silicon to PDMS and hydrogel starts with etching the desired structures in silicon as explained previously (Fig. 1) . In brief, a photomask parameter related to the geometrical value and etch time is generated based on the desired width and depth of structures as shown in Eqs.…”

Section: Methodsmentioning

confidence: 99%

“…For instance, in blood vessels, cells are interacting inside circular channels, with varying diameter along with multiple branches and joints, with each other and their surrounding ECM environment. In this report, we have extended our previous work in 3‐D tissue micropatterning, working toward much more complex and physiologically relevant surface topographies in 3‐D tissue utilizing a single mask, single etch process using reactive ion etching (RIE) lag.…”

Section: Introductionmentioning

confidence: 95%

Bio‐inspired microstructures in collagen type I hydrogel

Hosseini

Verbridge

Agah

2014

J Biomedical Materials Res

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This article presents a novel technique to fabricate complex type I collagen hydrogel structures, with varying depth and width defined by a single fabrication step. This technique takes advantage of reactive ion etching lag to fabricate three-dimensional (3-D) structures in silicon. Then, a polydimethylsiloxane replica was fabricated utilizing soft lithography and used as a stamp on collagen hydrogel to transfer these patterns. Endothelial cells were seeded on the hydrogel devices to measure their interaction with these more physiologically relevant cell culture surfaces. Confocal imaging was utilized to image the hydrogel devices to demonstrate the robustness of the fabrication technique, and to study the cell-extracellular matrix interaction after cell seeding. In this study, we observed that endothelial cells remodeled the sharp scallops of collagen hydrogel structures and compressed the structures with low degree of slope. Such patterning techniques will enhance the physiological relevance of existing 3-D cell culture platforms by providing a technical bridge between the high resolution yet planar techniques of standard lithography with more complex yet low resolution 3-D printing methods.

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“…For this work, oxide deposition was performed in a Trion Orion II PECVD machine and silicon etching was performed in an Alcatel AMS‐100 Deep Reactive Ion Etcher (DRIE). We utilize RIE lag and our previously published models to smoothly and arbitrarily vary the depth of the microfluidic channel in a single‐etch‐step process by changing the geometrical pattern on the mask layout. Different microchannel geometries can be fabricated on a single wafer using this technique, two of which are used in this work.…”

Section: Methodsmentioning

confidence: 99%

Silicon insulator‐based dielectrophoresis devices for minimized heating effects

Zellner¹,

Agah

2012

Electrophoresis

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Concentration of biological specimens that are extremely dilute in a solution is of paramount importance for their detection. Microfluidic chips based on insulator-based DEP (iDEP) have been used to selectively concentrate bacteria and viruses. iDEP biochips are currently fabricated with glass or polymer substrates to allow for high electric fields within the channels. Joule heating is a well-known problem in these substrates and can lead to decreased throughput and even device failure. In this work, we present, for the first time, highly efficient trapping and separation of particles in DC iDEP devices that are fabricated on silicon using a single-etch-step three-dimensional microfabrication process with greatly improved heat dissipation properties. Fabrication in silicon allows for greater heat dissipation for identical geometries and operating conditions. The 3D fabrication allows for higher performance at lower applied potentials. Thermal measurements were performed on both the presented silicon chips and previously published PDMS devices comprised of microposts. Trapping and separation of 1 and 2 μm polystyrene particles was demonstrated. These results demonstrate the feasibility of high-performance silicon iDEP devices for the next generation of sorting and concentration microsystems.

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A fabrication technology for three-dimensional micro total analysis systems

Cited by 30 publications

References 29 publications

Engineering microscale topographies to control the cell–substrate interface

Engineering microscale topographies to control the cell–substrate interface

Bio‐inspired microstructures in collagen type I hydrogel

Silicon insulator‐based dielectrophoresis devices for minimized heating effects

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