Enhanced fully cellulose based forward and reverse blood typing assay.

This study presents an enhanced paper-based analytical device (PAD) for forward and reverse group blood typing. The proposed PAD uses a novel methodology, which provides highly reliable results on a fully cellulose based device. The PAD was printed on different cellulose substrates. These substrates were made of different cellulose fibers (sisal and eucalyptus), different grammages, refining steps, and wet additive content. Best parameters were chosen to achieve high reliability on both forward and reverse blood typing. The substrates were patterned with five hydrophilic channels and two hydrophobic areas. For reverse blood typing, the hemoagglutination reaction took place on the hydrophobic surface of the paper before being transferred to the paper web, where together with the forward blood typing tests were all washed with saline solution to read the results by elution. This device allows direct read-out of results; the stains show were agglutination happens. Different blood types were in full agreement between the reverse and forward method and in agreement with traditional methods. The time and simplicity of this methodology confirmed its utility.

Novel applications of nonwood cellulose for blood typing assays.

Paper-based microfluidics devices can create a new healthcare model. Cellulose is carbohydrate polymer biocompatible and hydrophilic. These characteristics enhance the development of user-friendly diagnostic devices, but the link between paper manufacturing process and performance of the devices is still unclear. Previous studies focused on either commercial papers or lab papers from wood-cellulose fibers, with different basis-weight. This work introduces the effect of refining process and lab paper from nonwood-cellulose fibers, focusing on sisal fibers to overcome the aforementioned challenge. Structural characteristics of paper, such as basis-weight and degree of refining, are optimized and correlated with blood typing test resolution. Unrefined sisal paper of 50 g/m2 and 100 g/m2 basis-weight exhibit a higher gray intensity level than refined paper, and also maximal capillary rise and a pore size suitable for blood grouping tests. Two different blood types were evaluated with results consistent with the traditional methods, testifying the usefulness of this methodology. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1533-1541, 2019.