REPlicating RAPid microfluidics: self-replicating printer for hydrophobic pattern deposition

Abstract

Paper-based microfluidics broadens the use of point-of-care devices to applications and situations wherein cost is an important restriction. This study focuses on the REPRAP PRUSA i3 Printer that can print itself a part that combined with an infusion pump extends the capabilities of this printer, which can now create different types of hydrophobic patterns on an abundant, renewable substrate: paper. Different flow rates of the syringe pump and printing velocities are combined to optimize the resolution of this new manufacturing process. Besides different papers are used to print patterns to either check the influence of the paper type on the printing resolution or to choose the more suitable paper to build blood typing assays. The resolution improves decreasing flow rate and increasing printing velocity to a minimum value ~10% higher than the needle diameter. The printer working with a G25 needle prints microfluidic patterns that can be used to evaluate the blood type on different types of chromatographic papers. Two blood types (A- and O-) are evaluated with this new approach with results equivalent to traditional methods, validating its feasibility in clinical practice. This novel printing method for paper-based microfluidics manufacturing does not require specialized equipment or skills, it is fast and inexpensive, and thus can help to introduce the advantage of healthcare in areas where access to health systems is not guaranteed.