Capillary-Driven Toner-Based Microfluidic Devices for Clinical Diagnostics with Colorimetric Detection

Abstract

The fabrication of toner-based microfluidic devices to perform clinical diagnostics with capillary action and colorimetric detection is described in this report. Test zones and microfluidic channels were drawn in a graphic software package and laser printed on a polyester film. The printed layout and its mirror image were aligned with an intermediary cut-through polyester film and then thermally laminated together at 150 °C at 60 cm/min to obtain a channel with ca. 100-μm depth. Colorimetric assays for glucose, protein, and cholesterol were successfully performed using a desktop scanner. The limit of detection (LD) values found for protein, cholesterol, and glucose were 8, 0.2, and 0.3 mg/mL, respectively. The relative standard deviation (RSD) values for an interdevices comparison were 6%, 1%, and 3% for protein, cholesterol, and glucose, respectively. Bioassays were successfully performed on toner-based devices stored at different temperatures during five consecutive days without loss of activity.

Colorimetric Detection of Glucose in Biological Fluids Using Toner-Based Microzone Plates

“…31 The reason is associated with the poor color homogeneity inside detection zones on toner-based microfluidic devices. The poor uniformity is caused due to the weak interaction between enzymes and/or colorimetric indicators with the substrate surface allowing their loading to zone borders, thus resulting in the formation of a color gradient.…”

“…Furthermore, the mentioned electronic devices for image capture are globally affordable and their use do not require extensive training. This platform has been successfully used for capillary-driven flow based clinical assays 31 and dengue diagnostics through enzyme-linked immunosorbent assay (ELISA) on printed zones. 32 When compared to capillary-driven toner-based microfluidic devices, the laser printing of microzone array on transparency films is based on a single printing step, 32 while the fabrication of multilayer toner-based microfluidic devices require the laser cut of an intermediary transparency film, an alignment step and, finally, a thermal lamination to promote the channel sealing.…”

“…32 When compared to capillary-driven toner-based microfluidic devices, the laser printing of microzone array on transparency films is based on a single printing step, 32 while the fabrication of multilayer toner-based microfluidic devices require the laser cut of an intermediary transparency film, an alignment step and, finally, a thermal lamination to promote the channel sealing. 31 In this current report, we describe the use of tonerbased microzone plates for glucose analysis in biological fluids using colorimetric measurements. Glucose has been selected as a target analyte because of its clinical importance for diagnosis and monitoring of diabetes.…”

Towards nano-diagnostics for rapid diagnosis of infectious diseases – current technological state

“…For POC devices, visual detection and readout is desirable. In a recent work of Souza et al (34), a tonerbased device with colorimetric detection was presented. This design is based on a computer design that is laserprinted on a polyester film.…”

Calligraphy paper-based analytical devices

“…or an enzyme-linked immunosorbent assay (ELISA) [i.e., using antibodies to indicate specific target antigens, such as vascular endothelial growth factor (VEGF), hCG, NC16A, etc.] [2,5,[11][12][13]. Both PAD approaches offer promising strategies to ameliorate global health issues.…”