Sens Actuators B Chem

Numerous fabrication methods have been reported for microfluidic paper-based analytical devices (\u3bcPADs) using barrier materials ranging from photoresist to wax. While these methods have been used with wide success, consistently producing small, high-resolution features using materials and methods that are compatible with solvents and surfactants remains a challenge. Two new methods are presented here for generating \u3bcPADs with well-defined, high-resolution structures compatible with solvents and surfactant-containing solutions by partially or fully fusing paper with Parafilm\uae followed by cutting with a CO| laser cutter. Partial fusion leads to laminated paper (|-paper) while the complete fusion results in infused paper (|-paper). Patterned structures in |-paper were fabricated by selective removal of the paper but not the underlying Parafilm\uae using a benchtop CO| laser. Under optimized conditions, a gap as small as 137 \ub1 22 \u3bcm could be generated. Using this approach, a miniaturized paper 384-zone plate, consisting of circular detection elements with a diameter of 1.86 mm, was fabricated in 64 7 43 mm| area. Furthermore, these ablation-patterned substrates were confirmed to be compatible with surfactant solutions and common organic solvents (methanol, acetonitrile and dimethylformamide), which has been achieved by very few \u3bcPAD patterning techniques. Patterns in |-paper were created by completely cutting out zones of the |-paper and then fixing pre-cut paper into these openings similar to the strategy of fitting a jigsaw piece into a puzzle. Upon heating, unmodified paper was readily sealed into these openings due to partial reflow of the paraffin into the paper. This unique and simple bonding method was illustrated by two types of 3D \u3bcPADs, a push-on valve and a time-gated flow distributor, without adding adhesive layers. The free-standing jigsaw-patterned sheets showed good structural stability and solution compatibility, which provided a facile alternative method for fabricating complicated \u3bcPADs.R01 OH010662/OH/NIOSH CDC HHS/United States2019-02-01T00:00:00Z29180835PMC5701284vault:2527