Responsive Microgrooves for the Formation of Harvestable Tissue Constructs
Halil TekinGözde Özaydın İnceTonia TsinmanKaren K. GleasonRóbert LangerAli KhademhosseiniMelik C. Demirel
57
Citation
43
Reference
10
Related Paper
Citation Trend
Abstract:
Given its biocompatibility, elasticity, and gas permeability, poly(dimethylsiloxane) (PDMS) is widely used to fabricate microgrooves and microfluidic devices for three-dimensional (3D) cell culture studies. However, conformal coating of complex PDMS devices prepared by standard microfabrication techniques with desired chemical functionality is challenging. This study describes the conformal coating of PDMS microgrooves with poly(N-isopropylacrylamide) (PNIPAAm) by using initiated chemical vapor deposition (iCVD). These microgrooves guided the formation of tissue constructs from NIH-3T3 fibroblasts that could be retrieved by the temperature-dependent swelling property and hydrophilicity change of the PNIPAAm. The thickness of swollen PNIPAAm films at 24 °C was approximately 3 times greater than at 37 °C. Furthermore, PNIPAAm-coated microgroove surfaces exhibit increased hydrophilicity at 24 °C (contact angle θ = 30° ± 2) compared to 37 °C (θ = 50° ± 1). Thus PNIPAAm film on the microgrooves exhibits responsive swelling with higher hydrophilicity at room temperature, which could be used to retrieve tissue constructs. The resulting tissue constructs were the same size as the grooves and could be used as modules in tissue fabrication. Given its ability to form and retrieve cell aggregates and its integration with standard microfabrication, PNIPAAm-coated PDMS templates may become useful for 3D cell culture applications in tissue engineering and drug discovery.Keywords:
Biocompatibility
Conformal coating
PDMS stamp
Etertec HQ-6100 dry film photoresist was used in this work to fabricate soft-lithography masters applied to microfluidic applications. We demonstrated that the use of this photoresist was a convenient alternative to conventional microfabrication approaches based on DRIE and liquid photoresists for fast-prototyping of microfluidic structures. Our method was at least two times faster than conventional processes and required limited investment for equipments. Finally, this approach was applied to the design and fabrication of microfluidic networks used for gradient generation in bulk solution.
Photoresist
Soft Lithography
Rapid Prototyping
PDMS stamp
Cite
Citations (92)
Microcontact printing (μCP) has been used to produce patterned self-assembled monolayers (SAMs) with submicrometer features on curved substrates with radii of curvature as small as 25 micrometers. Wet-chemical etching that uses the patterned SAMs as resists transfers the patterns formed by μCP into gold. At present, there is no comparable method for microfabrication on curved surfaces.
Microcontact Printing
Cite
Citations (430)
We introduce a novel microfabrication method using direct writing of photoresist with an ultrasonic microplotter equipped. First, the photoresist is driven into the pipette through capillary forces. The pipette is then used to directly write microfeatures on a polydimethylsiloxane (PDMS) substrate. The photoresist is cured on a hot-plate and used as a mold for replication. A second layer of PDMS is cast onto the mold. Once cured on a hot-plate, it is peeled off from the mold to obtain the desired microfeatures. We demonstrate that this method can be used for ultra-rapid and cost-effective fabrication of microchannels (39.65 μm wide) without need for clean room facilities.
Polydimethylsiloxane
Photoresist
Pipette
PDMS stamp
Cite
Citations (0)
Abstract The chapter offers an introduction to microfabrication techniques. Photolithography is presented. Techniques dedicated to hard materials, such as wet and plasma etching, sputtering, bonding, electron beam lithography. Direct writing and 3D printing are shown. Soft lithography, and in particular those using PDMS (PolyDimethylSiloxane) is presented, with applications to valving, pumping, leading to Large Scale Integration Systems. Paper microfluidics is discussed, along with recent technological approaches, such as photosensitive hydrogels, NOA technology, microcontact printing or flow lithography.
Polydimethylsiloxane
Microcontact Printing
PDMS stamp
Soft Lithography
Cite
Citations (1)
Abstract Soft lithography enables rapid microfabrication of many types of microsystems by replica molding elastomers into master molds. However, master molds can be very costly, hard to fabricate, vulnerable to damage, and have limited casting life. Here, an approach for the multiplication of master molds into monolithic thermoplastic sheets for further soft lithographic fabrication is introduced. The technique is tested with master molds fabricated through photolithography, mechanical micromilling as well as 3D printing, and the results are demonstrated. Microstructures with submicron feature sizes and high aspect ratios are successfully copied. The copying fidelity of the technique is quantitatively characterized and the microfluidic devices fabricated through this technique are functionally tested. This approach is also used to combine different master molds with up to 19 unique geometries into a single monolithic copy mold in a single step displaying the effectiveness of the copying technique over a large footprint area to scale up the microfabrication. This microfabrication technique can be performed outside the cleanroom without using any sophisticated equipment, suggesting a simple way for high‐throughput rigid monolithic mold fabrication that can be used in analytical chemistry studies, biomedical research, and microelectromechanical systems.
Soft Lithography
Molding (decorative)
PDMS stamp
Cleanroom
Precision engineering
Photomask
Cite
Citations (18)
Here we demonstrate the microfabrication of deep (>25 μm) polymeric microstructures created by replica-molding polydimethylsiloxane (PDMS) from microfabricated Si substrates. The use of PDMS structures in microfluidics and biological applications is discussed. We investigated the feasibility of two methods for the microfabrication of the Si molds: deep plasma etch of silicon-on-insulator (SOI) wafers and photolithographic patterning of a spin-coated photoplastic layer. Although the SOI wafers can be patterned at higher resolution, we found that the inexpensive photoplastic yields similar replication fidelity. The latter is mostly limited by the mechanical stability of the replicated PDMS structures. As an example, we demonstrate the selective delivery of different cell suspensions to specific locations of a tissue culture substrate resulting in micropatterns of attached cells.
Polydimethylsiloxane
PDMS stamp
Soft Lithography
Molding (decorative)
Cite
Citations (172)
We present an original microfabrication-free procedure to flexibly design and fabricate 3-dimensional microchannels in polydimethylsiloxane (PDMS) elastomer with a single-step process using hydrogel molds. In this process, arranged small wires of agarose-gel serve as a mold for a microchannel formed within a piece of PDMS. The advantages of the method are that 3-dimensional microchannels can be flexibly designed and fabricated by a simple procedure without using any specialized equipment or processes. Hydrogel Molding promises to make microfluidic processes more accessible in a variety of fields, including fundamental biology, biomedical engineering, material sciences and would also provide an attractive educational material for students.
Polydimethylsiloxane
Microchannel
Molding (decorative)
PDMS stamp
Agarose
Cite
Citations (0)
We present an original microfabrication-free procedure to flexibly design and fabricate 3-dimensional microchannels in polydimethylsiloxane (PDMS) elastomer with a single-step process using hydrogel molds. In this process, arranged small wires of agarose-gel serve as a mold for a microchannel formed within a piece of PDMS. The advantages of the method are that 3-dimensional microchannels can be flexibly designed and fabricated by a simple procedure without using any specialized equipment or processes. This method would make microfluidic processes more accessible for laboratories of a variety of fields, and would also provide an attractive educational material for students.
Polydimethylsiloxane
Microchannel
PDMS stamp
Agarose
Cite
Citations (2)
The fabrication of complex patterns of aligned microstructures has required the use of multiple applications of lithography. Here we describe an approach for microfabrication that encodes the two-dimensional spatial information of several photomasks onto a single elastomeric stamp by mapping each photomask onto distinct heights on the surface of the stamp. Pressing the stamp against a surface collapses the topography of the stamp such that each recessed layer contacts the surface in stepwise sequence; the greater the applied pressure, the larger the area of the stamp that contacts the surface. After contact of each new layer with the surface, we use techniques of soft lithography (microcontact printing, microfluidics, and patterning through membranes) to pattern the surfaces that contact the stamp and those that do not with inorganic, organic, or living materials. Microfabrication through the use of multilevel stamps provides a promising alternative to conventional lithography for the construction of multicomponent, aligned surfaces; these structures may find use as components of microfluidic devices or biological patterns.
Photomask
Soft Lithography
Microcontact Printing
PDMS stamp
Cite
Citations (148)
Polydimethylsiloxane
Engraving
PDMS stamp
Polystyrene
Photoresist
Polycarbonate
Cite
Citations (10)