Fabrication techniques polydimethylsiloxane

The development of a cellular microenvironment in a microfluidic chip starts with device fabrication. The most commonly used material for fabrication is polydimethylsiloxane (PDMS). One of the most important components to develop such platforms is the extracellular matrix (ECM), which is the 3D cellular microenvironment. Different approaches have been followed to pattern the ECM inside the microfluidic device, which will significantly affect the arrangement of cells on the chip. Following this, the target cells are seeded and cultured. Such cell culture techniques would be common for drug screening as well as the fundamental research. But for CTCs detection, usually the antibodies will be immobilized on the chip before introducing the cells. 

Hosokawa K, Maeda R (2000) A pneumatically-actuated three-way microvalve fabricated with polydimethylsiloxane using the membrane transfer technique. J Micromech Microeng 10(3) 415 20... 

The top microfluidic architecture was fabricated using a multilayer soft lithography technique with polydimethylsiloxane (PDMS). In the figure, we illustrate a... 

Novel microreactors with immobilized enzymes were fabricated using both silicon and polymer-based microfabrication techniques. The effectiveness of these reactors was examined along with their behavior over time. Urease enzyme was successfully incorporated into microchannels of a polymeric matrix of polydimethylsiloxane and through layer-bylayer self-assembly techniques onto silicon. The fabricated microchannels had cross-sectional dimensions ranging from tens to hundreds of micrometers in width and height. The experimental results for continuous-flow microreactors are reported for the conversion of urea to ammonia by urease enzyme. Urea conversions of >90% were observed. 

Microchannels created using dry etching techniques on silicon-based substrates often have a cross section that is close to a rectangle. This geometry is also common in polymer-based microchips, e.g., created using PDMS (polydimethylsiloxane) material, which are popularly used in the research commxmity due to their simpler fabrication procedure. The effect of the rectangular geometry on the hydrodynamic... 

The use of polymeric materials in microchips has gained popularity, especially in the fabrication of low-cost, disposable devices [3], It is particularly common to prototype polydimethylsiloxane (PDMS) chips, which can easily be fabricated using the soft lithography technique. This fabrication strategy is considered as a low-expertise route of microscale prototyping. It facilitates creation of micropatterns on a surface or within a microfluidic channel without the need for using photochemical processes [9]. Fabrication... 

Soft hthographic techniques offer a convenient, cost-effective alternative to conventional fabrication methods because they do not require (i) speciahzed equipment, (ii) expensive clean-room facihties, or (iii) high operational costs. Soft hthography takes advantage of a soft, patterned elastomer, such as polydimethylsiloxane (PDMS) to replicate and transfer patterns from one smface to another (5). This inherently parallel process offers the abihty to (i) pattern complex molecules, (ii) control chemical structure of surfaces, (hi) create channels for microfluidics, and (iv) pattern features over large areas (> 50 cm ) on non-planar surfaces using ordinary lab facihties. Depending on the... 

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