Integrated calibration and serum iron in situ analysis into an array microfluidic paper-based analytical device with smartphone readout

Paper-Based Analytical Devices for Accurate Assessment of Transferrin Saturation in Diagnosed Clinical Samples from Ischemic Stroke Patients

“…Next, the backside of the printing surface was covered with clear packing tape to prevent the solution from leaking out underneath the PAD. 27 The device consisted of six circular zones (detection reservoirs, 10 mm diameter) at the ends of six channels (10 mm length and 5 mm width), in a radial configuration where only the circular zones were used, assuring that all reservoirs are at the same distance from the point of light. This fact is very important since in this application, two different parameters (Tf-bound iron and TIBC) were measured simultaneously, which allows the accurate assessment of the TSAT as a ratio of both.…”

“…Ferrozine was used as a colorimetric agent because it is commonly used for the colorimetric iron assay. − The optimal conditions of this chromogenic reagent were chosen based on our previous article . 0.5 μL of 49 mg mL –1 ferrozine in 2 M acetate buffer of pH 4.8 was added to each detection reservoir of PAD, and it was dried completely in an oven at 60 °C for 2 min.…”

“…Once the PADs were drawn on the filter paper, they were individually cut using the cutter plot (the blade was reinstalled), and it was checked whether the hydrophobic walls were well-created with the waterproof marker pen on both sides of the device. Next, the backside of the printing surface was covered with clear packing tape to prevent the solution from leaking out underneath the PAD …”

“…In the designing and developing of a novel POCT, paper-based analytical devices (PADs) offer several advantages such as inexpensive production, portability, operational simplicity, miniaturization, biocompatibility, minimal reagent consumption, disposability, and capillary flow. − There are interesting examples of (μ)­PADs with smartphone-based detection for serum iron − and serum ferritin quantification (lateral flow assay) but, to our best knowledge, there is no article reporting on TSAT assessment using a PAD approach.…”

Paper-based microfluidics in sweat detection: from design to application

“…[38][39][40] Patterned paper is ideal for low-cost, portable, and technically simple multiplexed bioassays. [41][42][43][44] Paper-based microfluidics offer many unique advantages over conventional microfluidics in terms of unpowered fluid transport via capillary action, high surface area to volume ratio for chemical reactions and assays, and the ability to store reagents in an active form within the fiber network. 45 With the advantages mentioned above, paper has become an attractive substrate material for in situ sweat detection, which makes it a promising starting point for a "lab on paper".…”