Microfluidic Chips for Life Sciences—A Comparison of Low Entry Manufacturing Technologies

Abstract

mixing. These features can often accelerate or even enable reactions to proceed. [4] A key factor for the successful dissemination of this technology is the ability for production of masters for molding microfluidic droplet generators and related accessories through rapid prototyping with low associated manufacturing and material costs, because only few ready-to-use microfluidic devices are currently commercially available and their geometries are usually limited to standard applications.Soft lithography using SU-8 masters is the gold standard for the production of microfluidic prototypes. [5] In this method, an SU-8 photoresist is structured by means of optical lithography and the resulting negative structure is then molded by soft lithography into polydimethylsiloxane (PDMS). For sealing, the elastomeric PDMS chips are usually plasma bonded onto glass supports. The very high structural resolution along with excellent surface quality in terms of low roughness is the major advantages of this technology, whereas low aspect ratios and difficulties in the production of variable heights in a single chip, along with high machine costs and the requirement of clean room facilities for the production of masters, are on the downside. Since trained clean room personnel and expensive infrastructure are often not available in research institutes engaged in biomedical research and the life sciences, there is a great demand for alternative costeffective manufacturing processes for microfluidic chips.The implementation of additive manufacturing (AM) methods in microfluidic prototyping is currently attracting Microfluidic water-in-oil droplets are a versatile tool for biological and biochemical applications due to the advantages of extremely small monodisperse reaction vessels in the pL-nL range. A key factor for the successful dissemination of this technology to life science laboratory users is the ability to produce microfluidic droplet generators and related accessories by low-entry barrier methods, which enable rapid prototyping and manufacturing of devices with low instrument and material costs. The direct, experimental side-by-side comparison of three commonly used additive manufacturing (AM) methods, namely fused deposition modeling (FDM), inkjet printing (InkJ), and stereolithography (SLA), is reported. As a benchmark, micromilling (MM) is used as an established method. To demonstrate which of these methods can be easily applied by the non-expert to realize applications in topical fields of biochemistry and microbiology, the methods are evaluated with regard to their limits for the minimum structure resolution in all three spatial directions. The suitability of functional SLA and MM chips to replace classic SU-8 prototypes is demonstrated on the basis of representative application cases. Microfluidic ManufacturingProf. R. Mikut

Influence of the Degree of Cure in the Bulk Properties of Graphite Nanoplatelets Nanocomposites Printed via Stereolithography

“…Although there are some epoxy-based resin precursors, most widespread SLA precursors are of an acrylic nature [20]. Several groups have successfully modified these precursors with different nanofillers in the design of complex, lightweight nanocomposites for different applications such as microfluidic devices [21], metamaterials [22] or scaffolds for stem cells [23].…”

Segregation of Dispersed Silica Nanoparticles in Microfluidic Water‐in‐Oil Droplets: A Kinetic Study

“…An aqueous dispersion of spherically shaped core/shell SiNP (about 90 nm in diameter, as analyzed by TEM, Figure S1 in the Supporting Information) containing a Cy5‐fluorescently labeled core was used as a dispersed phase, and mineral oil (MO) supplemented with positively charged 1,2‐Dioleoyl‐3‐trimethylammonium‐propane (DOTAP) lipid supplemented with 0.1 mol % of 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphoethanolamine‐N‐(lissamine rhodamine B sulfonyl) (Rh‐PE) was employed as the continuous phase to generate monodisperse water in oil (W/O) droplets. The two reagent solutions were injected into the inlets of a microfluidic chip made of poly (methyl methacrylate) (PMMA), fabricated by micro‐milling, as previously reported . By controlling the flowrates of the aqueous and continuous phase, highly monodispersed W/O droplets of about 180–200 μm diameter were generated with the microfluidic flow‐focusing chip.…”

Microfluidic Evolution‐On‐A‐Chip Reveals New Mutations that Cause Antibiotic Resistance

“…The chip's geometry as well as the cover were first designed using the computer aided‐design (CAD) software Inventor Professional 2015 (Autodesk Inc., USA), then fabricated as a mold on an 8 mm‐thick PMMA, (Evonik Industries) block using micro‐milling (Mini Mill GX, Minitech Machinery, US). [ 65 ] The milling program and code was constructed by the software Inventor HSM Pro (Autodesk Inc., USA). After milling, the PMMA molds were cleaned by pressurized air and washed with distilled water.…”