Colored Pencils Developed for Easy Chemical-based Diag**stic Testing Thanks to a team of researchers from California Polytechnic State*University, chemicals formed into Pencils can be used to react with each other by simply drawing*with them on a piece of paper. The work, published recently in the journal Lab on a Chip, is based on*a well-k**wn technique called paper-based microfluidics, which uses the capillary effect of paper to*mix chemicals, indicating the presence or absence of a substance. The channels on the paper are made*using waxy ink, and the chemicals are deposited in the channels by drawing between*the lines. When water is added to the channels, it forces the chemicals to move due to*capillary action and react with one other. As a proof-of-concept, the team tested Pencils loaded with*chemicals such as horseradish peroxidase (HRP) for monitoring blood glucose levels, and the results*were identical to that using the traditional approach of finger pricking with a chemical solution.
Additionally, the reagents used for the test are stable for two months in the pencil form, whereas as*liquids they degrade within a few days, making transport and storage easier and less expensive. From*the abstract of the paper, “Reagent Pencils offer a new option for preparing and customizing Diag**stic tests at the point of care*without the need for specialized equipment.”