Rapid production of Plasmodium sporozoite detection paper dipstick assays using cellulose nanocrystals: Proof‐of‐concept for bio‐based, locally developed, point‐of‐care devices

Abstract Enhanced and rapid surveillance for diseases is critical to public health and meeting United Nations' Sustainable Development Goal for Good Health and Well‐being by allowing for targeted and accelerated prevention and control response strategies. Human malaria, caused by Plasmodium spp. and transmitted by mosquitoes is no exception. Advances in sustainable materials provide an opportunity to improve fast, sustainable, and equitable testing assays. Here, naturally abundant polymers and biomaterials, such as cellulose nanocrystals (CNCs) and chitosan, were used to increase antibody density deposition on the assay detection line when compared to traditional free antibody deposition, and thus the sensitivity, of easily assembled rapid tests designed to detect Plasmodium vivax infective (sporozoite) parasites in mosquitoes, a critical indicator of malaria transmission. The immobilization of antibodies onto chitosan‐coated CNCs allowed for antigen detection with a lower number of antibodies used in each test; likewise, the immobilization allowed to directly place the CNC‐Ab without the traditionally needed blockers layer on the paper like bovine serum albumin (BSA). This bio‐based prototype of a paper‐based dipstick assay shows a promising pathway for the development of rapid disease surveillance tools using sustainable and globally available materials.