Fabrication of NOA microfluidic devices based on sequential replica molding

Sim, Jae Hwan; Moon, Hyun June; Roh, Yoon Ho; Jung, Hyun Wook; Bong, Ki Wan

doi:10.1007/s11814-017-0041-1

Cited by 12 publications

(9 citation statements)

References 48 publications

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“…With the microfluidic device mounted on an inverted microscope (Axiovert 200, Zeiss), the prepolymer solution was loaded into the device inlet in a pipette tip reservoir. 37 With a Tygon tube, the reservoir was connected to a compressed air tank, bridged by a pressure regulator (ITV0031-3BL, SMC Pneumatics). A photomask, designed using AutoCAD and printed using a high-resolution printer (50 000 dpi), was embedded into the field-stop of the microscope.…”

Section: B Stop Flow Lithography Setupmentioning

confidence: 99%

Low temperature flow lithography

et al. 2018

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Flow lithography (FL) is a microfluidic technique distinguished for its ability to produce hydrogel microparticles of various geometrical and chemical designs. While FL is typically performed in room temperature, this paper reports a new technique called low temperature flow lithography that uses low synthesis temperature to increase the degree of polymerization of microparticles without compromising other aspects of flow lithography. We suggest that decreased oxygen diffusivity in low temperature is responsible for the increase in polymerization. Microparticles that exhibit a higher degree of polymerization display a more developed polymer network, ultimately resulting in a more defined morphology, higher incorporation of materials of interest, and improved functional performance. This work demonstrates the increase in the degree of polymerization by examining the temperature effect on both the physical and chemical structures of particles. We show applications of this technique in synthesizing thin microparticles and enhancing microparticle-based detection of microRNA. Low temperature FL offers a simple and easy method of improving the degree of polymerization, which can be implemented in a wide range of FL applications.

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Section: B Stop Flow Lithography Setupmentioning

confidence: 99%

Low temperature flow lithography

et al. 2018

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“…We chose a composite microchip design that features an OA channel as the core element. Unlike previously reported methods that use fully NOA81-based microfluidic chips 33 – 35 , here we provide an alternative way to use NOA68 to fabricate a chip featuring a sandwich structure with multiple materials. The chip provides an overall rigid and accurately defined microfluidic structure that is easier to fabricate than a full glass or polymer chip that might require additional etching or hot embossing techniques 44 .…”

Section: Discussionmentioning

confidence: 99%

“…The microfluidic chip was fabricated using an optical adhesive (OA)-based protocol that was adapted from previously published papers 33 – 35 . Unlike these approaches, our chip consists of a glass-OA-poly(methyl methacrylate) (PMMA) composite structure.…”

Section: Methodsmentioning

confidence: 99%

Effect of inoculum size and antibiotics on bacterial traveling bands in a thin microchannel defined by optical adhesive

2021

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Phenotypic diversity in bacterial flagella-induced motility leads to complex collective swimming patterns, appearing as traveling bands with transient locally enhanced cell densities. Traveling bands are known to be a bacterial chemotactic response to self-generated nutrient gradients during growth in resource-limited microenvironments. In this work, we studied different parameters of Escherichia coli (E. coli) collective migration, in particular the quantity of bacteria introduced initially in a microfluidic chip (inoculum size) and their exposure to antibiotics (ampicillin, ciprofloxacin, and gentamicin). We developed a hybrid polymer-glass chip with an intermediate optical adhesive layer featuring the microfluidic channel, enabling high-content imaging of the migration dynamics in a single bacterial layer, i.e., bacteria are confined in a quasi-2D space that is fully observable with a high-magnification microscope objective. On-chip bacterial motility and traveling band analysis was performed based on individual bacterial trajectories by means of custom-developed algorithms. Quantifications of swimming speed, tumble bias and effective diffusion properties allowed the assessment of phenotypic heterogeneity, resulting in variations in transient cell density distributions and swimming performance. We found that incubation of isogeneic E. coli with different inoculum sizes eventually generated different swimming phenotype distributions. Interestingly, incubation with antimicrobials promoted bacterial chemotaxis in specific cases, despite growth inhibition. Moreover, E. coli filamentation in the presence of antibiotics was assessed, and the impact on motility was evaluated. We propose that the observation of traveling bands can be explored as an alternative for fast antimicrobial susceptibility testing.

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“…Nevertheless, PDMS blades have been successful in cutting very soft cells and organoids (see section ). Some studies have explored using stiff polymers or silicon in microfluidic devices to overcome these limitations. , However, factors such as the ease of fabrication and integration with the rest of the microfluidic system must be considered when selecting a material for the cutting tool.…”

Section: Principles Of Microscale Surgery and Implications For The De...mentioning

confidence: 99%

Microfluidic Surgery in Single Cells and Multicellular Systems

et al. 2022

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Microscale surgery on single cells and small organisms has enabled major advances in fundamental biology and in engineering biological systems. Examples of applications range from wound healing and regeneration studies to the generation of hybridoma to produce monoclonal antibodies. Even today, these surgical operations are often performed manually, but they are labor intensive and lack reproducibility. Microfluidics has emerged as a powerful technology to control and manipulate cells and multicellular systems at the micro- and nanoscale with high precision. Here, we review the physical and chemical mechanisms of microscale surgery and the corresponding design principles, applications, and implementations in microfluidic systems. We consider four types of surgical operations: (1) sectioning, which splits a biological entity into multiple parts, (2) ablation, which destroys part of an entity, (3) biopsy, which extracts materials from within a living cell, and (4) fusion, which joins multiple entities into one. For each type of surgery, we summarize the motivating applications and the microfluidic devices developed. Throughout this review, we highlight existing challenges and opportunities. We hope that this review will inspire scientists and engineers to continue to explore and improve microfluidic surgical methods.

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Fabrication of NOA microfluidic devices based on sequential replica molding

Cited by 12 publications

References 48 publications

Low temperature flow lithography

Low temperature flow lithography

Effect of inoculum size and antibiotics on bacterial traveling bands in a thin microchannel defined by optical adhesive

Microfluidic Surgery in Single Cells and Multicellular Systems

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