Inkjet-Printed Microfluidic Multianalyte Chemical Sensing Paper

Abstract

This paper presents an inkjet printing method for the fabrication of entire microfluidic multianalyte chemical sensing devices made from paper suitable for quantitative analysis, requiring only a single printing apparatus. An inkjet printing device is used for the fabrication of three-dimensional hydrophilic microfluidic patterns (550-mum-wide flow channels) and sensing areas (1.5 mm x 1.5 mm squares) on filter paper, by inkjet etching, and thereby locally dissolving a hydrophobic poly(styrene) layer obtained by soaking of the filter paper in a 1 wt % solution of poly(styrene) in toluene. In a second step, the same inkjet printing device is used to print "chemical sensing inks", comprising the necessary reagents for colorimetric analytical assays, into well-defined areas of the patterned microfluidic paper devices. The arrangement of the patterns, printed inks, and sensing areas was optimized to obtain homogeneous color responses. The results are "all-inkjet-printed" chemical sensing devices for the simultaneous determination of pH, total protein, and glucose in clinically relevant concentration ranges for urine analysis (0.46-46 muM for human serum albumin, 2.8-28.0 mM for glucose, and pH 5-9). Quantitative data are obtained by digital color analysis in the L*a*b* color space by means of a color scanner and a simple computer program.

Sustainable monitoring of Zn(II) in biological fluids using office paper

“…Although the lignin removal during pulping processes requires the use of chemicals that may pollute the environment, plastic is made by monomers derived from oil or gas, by addition of various additives, reflecting in a higher pollution when compared with paper. Whitesides' group [6][7][8] and others [9][10][11][12][13][14][15][16] reported intriguing paper-based sensing platforms capable of measuring glucose, ethanol, proteins, ions, pollutants, etc. To realize paper-based POC devices, the presence of hydrophobic/hydrophilic areas is necessary to accomplish the measurement.…”

Thread as a Matrix for Biomedical Assays

“…We and others have used hydrophilic paper as the basis for diagnostic assays (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). One strategy for using paper for diagnostic devices is to pattern channels into the paper using lines of hydrophobic polymer; the hydrophilic channels thus define the microfluidic paper analytical devices (µ-PADs) (3).…”

Inkjet printed LED based pH chemical sensor for gas sensing

“…Inkjet printing has gradually become a versatile tool for accurately depositing very small quantities (tens of picoliters) of materials at defined positions on the surface of a wide variety of substrates. So far within scientific research, inkjet printing has been mostly applied to the manufacture of polymer light emitting diodes [29][30][31][32], deposition of conducting polymers [6,[33][34][35] and fluorescent nanoparticles [36] and fabrication of biosensors [37,38]. Inkjet printing offers advantages over other methods of deposition of thin films, such as patterning capability, reduction in waste products, high speed production, low cost fabrication, room temperature deposition, printing on large area and flexible substrates [6].…”

“…Inkjet printing offers advantages over other methods of deposition of thin films, such as patterning capability, reduction in waste products, high speed production, low cost fabrication, room temperature deposition, printing on large area and flexible substrates [6]. Additional advantages include direct patterning of a substrate surface as inkjet printing does not rely on the use of a specific mask, compared to the multistep process of photolithography [32]. It also allows the operator great freedom with regard to the pattern that can be printed, and the thickness at which the material is deposited.…”

“…The design template is also simple to create using the associated printer software, compared to the individually designed masks required for screen printing or the complex programming for some other deposition instruments [35]. Also inkjet printing is a non-contact method which, in contrast to contact based methods such as pin spotting systems, has the advantages of reduced contamination and no risk of substrate damage [32,39,40]. The prospect of deposition of more than one material is also a definite possibility with multiple ink reservoirs available in standard inkjet printers [35].…”