A rapid, maskless 3D prototyping for fabrication of capillary circuits: Toward urinary protein detection

Abstract

Proteinuria is an established risk marker for progressive renal function loss and patients would significantly benefit from a point-of-care testing. Although extensive work has been done to develop the microfluidic devices for the detection of urinary protein, they need the complicated operation and bulky peripherals. Here, we present a rapid, maskless 3D prototyping for fabrication of capillary fluidic circuits using laser engraving. The capillary circuits can be fabricated in a short amount of time (<10 min) without the requirements of clean-room facilities and photomasks. The advanced capillary components (e.g., trigger valves, retention valves and retention bursting valves) were fabricated, enabling the sequential liquid delivery and sample-reagent mixing. With the integration of smartphone-based detection platform, the microfluidic device can quantify the urinary protein via a colorimetric analysis. By eliminating the bulky and expensive equipment, this smartphone-based detection platform is portable for on-site quantitative detection.

Fabrication Methods for Microfluidic Devices: An Overview

“…Mohammed et al [136] used a CO 2 laser engraving/cutting system (Trotec SP500, Australia) and a low power, multi-pass engraving with a solvent polymer reflow to reduce the imperfections and achieve to both small (50-500 µm) and large (> 500 µm) features within a microfluidic device. Li et al [137] used a CO 2 laser (ILS9.75, Universal Laser Systems, Inc., USA) to create capillary circuit components (trigger valves, retention valves, and retention bursting valves) within a PDMS substrate for sequential liquid delivery and sample reagent mixing. Gas-actuated microvalves and a peristaltic micropump [138] were created using an unfocused CO 2 laser (VLS2.30, 25 W, wavelength 10.6 µm, Universal Laser Systems, USA) beam and surface treatment to create smooth semi-circular channels within PMMA and a flexible thermoplastic polyurethane (TPU) membrane that was thermally bonded between PMMA sheets.…”

Capillary microfluidics in microchannels: from microfluidic networks to capillaric circuits

“…124 Using the CC, they showed colorimetric detection of spiked BSA in synthetic urine with integrated optical readout using a smartphone in 25 min. Although successful, several challenges and limitations are apparent.…”

Capillary-driven microfluidics: impacts of 3D manufacturing on bioanalytical devices

“…8b). 60 This study employed a portable smartphone-based detection platform to increase usability and provide a user-friendly alternative. Qu et al 61 presented a POC adalimumab sensor for therapeutic drug monitoring.…”

“…(a) SARS-CoV-2 antibody detection in saliva by the sequential and pre-programmed release of 8 reagents in the capillary 3D circuit 33. (b) Quantifying the urinary protein via a colorimetric analysis 60. (c) Autonomous ELISA using IgE, anti-IgE, ALP-conjugate, and NBT-BCIP substrates respectively using a 3D-printed capillary microfluidic device 51.…”