FLASH: A rapid method for prototyping paper-based microfluidic devices

Department of Chemistry & Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Lab on a Chip (Impact Factor: 6.12). 01/2009; 8(12):2146-50. DOI: 10.1039/b811135a
Source: PubMed


This article describes FLASH (Fast Lithographic Activation of Sheets), a rapid method for laboratory prototyping of microfluidic devices in paper. Paper-based microfluidic devices are emerging as a new technology for applications in diagnostics for the developing world, where low cost and simplicity are essential. FLASH is based on photolithography, but requires only a UV lamp and a hotplate; no clean-room or special facilities are required (FLASH patterning can even be performed in sunlight if a UV lamp and hotplate are unavailable). The method provides channels in paper with dimensions as small as 200 microm in width and 70 microm in height; the height is defined by the thickness of the paper. Photomasks for patterning paper-based microfluidic devices can be printed using an ink-jet printer or photocopier, or drawn by hand using a waterproof black pen. FLASH provides a straightforward method for prototyping paper-based microfluidic devices in regions where the technological support for conventional photolithography is not available.

Download full-text


Available from: Scott T Phillips, Mar 11, 2015
  • Source
    • "fabricated in controlled environments (cleanrooms) with a standard subtractive lithographic process, thus producing chemicals waste and costly products. Nowadays, several techniques are proposed: laser etched fluidics, craft cut fluidics and wax impregnated capillary action fluidics on paper; all of these methods can be implemented outside of a cleanroom and in a simple way [5]–[7]. However, one issue consists still of integration of the electronic part with the microfluidic, keeping the fabrication cost low, given the fact that to pattern interface and sensing microelectronics onto the chip requires, by now, the use of standard etching technology. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, a review of recent improvements on inkjet-printed microfluidic-based tunable/sensing RF systems is reported. The devices, such as Radio Frequency IDentification (RFID) passive wireless tags, coplanar patch antennas, bandstop filters, and loop antennas, are all fabricated by combining the inkjet printing technology on photographic paper for metallization and bonding layers, and laser etching for cavities and channels manufacturing. A novelty is also introduced for the loop antennas where the photographic paper is replaced with a polymer based substrate [i.e., (Poly(methyl-methacrylate))], to reduce the substrate losses for the RF part and solve the issue of paper hydrophylia. Along this paper an evolution toward higher working frequencies and higher detecting performance is shown, demonstrating a sensitivity up to $0.5%/varepsilon _{r}$ with at most $6,mu text {L}$ of liquid in the channel.
    IEEE Sensors Journal 06/2015; 15(6):3156-3163. DOI:10.1109/JSEN.2014.2374874 · 1.76 Impact Factor
    • "More recently, paper has garnered significant attention as a low-cost disposable platform for chemical and biological assays [2] [3]. Paper-based devices are often fabricated either by using a hydrophilic paper that is patterned and impregnated with wax [4] [5] or other hydrophobic materials to create water-repelling regions [6] [7], or alternatively by laser-treating a hydrophobic paper to create hydrophilic regions [8] [9]. In both cases, the hydrophilic/ hygroscopic pattern is then used to perform colorimetric or electrochemical analyses on aqueous samples [10] [11]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A commercially available Janus paper with one hydrophobic (polyethylene-coated) face and a hygroscopic/hydrophilic one is irreversibly bonded to a polydimethylsiloxane (PDMS) substrate incorporating microfluidic channels via corona discharge surface treatment. The bond strength between the polymer-coated side and PDMS is characterized as a function of corona treatment time and annealing temperature/time. A maximum strength of 392 kPa is obtained with a 2 min corona treatment followed by 60 min of annealing at 120 °C. The water contact angle of the corona-treated polymer side decreases with increased discharge duration from 98° to 22°. The hygroscopic/hydrophilic side is seeded with human lung fibroblast cells encapsulated in a methacrylated gelatin (GelMA) hydrogel to show the potential of this technology for nutrient and chemical delivery in an air–liquid interface cell culture.
    Journal of Micromechanics and Microengineering 05/2015; 25(5). DOI:10.1088/0960-1317/25/5/055015 · 1.73 Impact Factor
  • Source
    • "In addition, in the proposed nonwoven based sensor, during patterning the isotropic structure of the nonwoven substrate provides an even spreading of photoresist polymer in x,y-plane as well as z direction through the entire fabric thickness which is critical for creating a welldemarcated hydrophobic-hydrophilic contrast of the pattern. The two-dimensional orientation of fibers in x,y-plane of a sheet of paper has been reported as a constraint since the liquid polymer tends to spread in the x,y-plane of paper rather than in the zdirection leading to blurring of the patterns [12] [31] [33] [34]. A good hydrophobic-hydrophilic contrast of the pattern is also required to avoid the leakage of the fluid consisting of the analyte through the channels and spreading through the device. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This study focuses on the fabrication of a novel, flexible and disposable textile based biosensing platform by the use of an absorbent microfibrous nonwoven substrate as the base material. This platform was fabricated via photolithography technique. Physical barriers were designed using a hydrophobic photo-resist polymer which defined the liquid penetration pathways on the fabric surface. A good hydrophilic/hydrophobic contrast of the fabricated patterns on the fabric and a well-controlled liquid capillary penetration was achieved in the patterns. The potential of the system was tested by constructing an enzyme biosensor based on colorimetric detection of hydrogen peroxide. To obtain a more enhanced and reproducible signal, the reservoirs were modified with gelatin and a linear working range of 0.1–0.6 μM H2O2 was obtained. The system could work on temperatures as high as 50 °C without any loss in the signal and in a pH range of 3.0–7.0. This bio-sensing platform may later be combined by H2O2 producing oxidases such as glucose oxidase, lactate oxidase, etc. and used for the rapid detection of various kinds of important analytes. http://www.sciencedirect.com/science/article/pii/S0925400514014129
    Sensors and Actuators B Chemical 03/2015; 208:475-484. DOI:10.1016/j.snb.2014.11.042 · 4.10 Impact Factor
Show more