A novel fabrication technique to minimize poly(dimethylsiloxane)‐microchannels deformation under high‐pressure operation

Abstract

PDMS is one of the most common materials used for the flow delivery in the microfluidics chips, since it is clear, inert, nontoxic, and nonflammable. Its inexpensiveness, straightforward fabrication, and biological compatibility have made it a favorite material in the exploratory stages of the bio-microfluidic devices. If small footprint assays want to be performed while keeping the throughput, high pressure-rated channels should be used, but PDMS flexibility causes an important issue since it can generate a large variation of microchannel geometry. In this work, a novel fabrication technique based on the prevention of PDMS deformation is developed. A photo-sensible thiolene resin (Norland Optical Adhesive 63, NOA 63) is used to create a rigid coating layer over the stiff PDMS micropillar array, which significantly reduces the pressure-induced shape changes. This method uses the exact same soft lithography manufacturing equipment. The verification of the presented technique was investigated experimentally and numerically and the manufactured samples showed a deformation 70% lower than PDMS conventional samples.

Recent advances in nonbiofouling PDMS surface modification strategies applicable to microfluidic technology

“…Gervais et al provided theoretical and experimental verification of the extent of PDMS deformation inside rectangular microchannels using confocal microscopy and related the change in height to position along the length of the channel, channel pressure, and the material properties of PDMS 59 . Recently, Mamadi and his colleagues used a photo-sensitive thiolene resin to create a rigid coating layer over the stiff PDMS micropillar array that reduced deformation by 70% compared with conventionally manufactured samples 60 .…”

“…A variety of coating materials such as chitosan 106 , poly(L-lysine) (PLL) 60,107 and poly(ethylene imine) (PEI) 108 have been grafted with PEG for preventing protein nonspecific binding. Lee and Voros reported the adsorption of poly(L-lysine)- graft -poly(ethylene glycol) (PLL- g -PEG) copolymer onto an oxygen plasma treated PDMS surface from an aqueous solution.…”

Safe and cost-effective rapid-prototyping of multilayer PMMA microfluidic devices

“…PMMA is therefore preferred, together with plastics like polystyrene, polycarbonate and cyclic olefin copolymer, for the manufacturing of disposable devices required for commercially orientated applications (Romoli et al 2011). PMMA structures can be created by a wide range of techniques including hot embossing, injection moulding, laser ablation, reactive ion etching or deep UV lithography and have mechanical properties superior to those of poly(dimethylsiloxane) (PDMS, another material of choice for microfluidic applications), guaranteeing a better fidelity to the initial shape under mechanical stress conditions (Madadi et al 2013). However, sealing of PMMA devices is not as straightforward as that of more conventional materials used traditionally in Abstract The rapid translation of research from bench to bedside, as well as the generation of commercial impact, has never been more important for both academic and industrial researchers.…”

Optically clear biomicroviscometer with modular geometry using disposable PDMS chips

“…Studies have been conducted for deformation of different microchannel structures in PDMS bonded to glass, such as deformation of micropillars [81], [82], rectangular channels due to solvents [83], [84], and rectangular channels due to DI water solutions [83], [85]. The specification range and microfluidic chip configuration of the present design are different from these studies in terms of aspect ratio, applied pressure and dimensions.…”

“…The specification range and microfluidic chip configuration of the present design are different from these studies in terms of aspect ratio, applied pressure and dimensions. Micropillars with diameter × height × spacing of 25 × 6 × 30 μm in a microfluidic chip 1 mm thick experienced about 1% change in deformation due to a pressure of approximately 4.99 × 10 3 Pa [82].…”