Application of the aqueous two-phase system and nanozyme signal enhancement for the improved detection of Plasmodium lactate dehydrogenase in serum.

Malaria is an infectious disease that can cause severe sickness and death if not diagnosed and treated in a timely manner. The current gold standard technique for malaria diagnosis is microscopy, which requires a dedicated laboratory setting and trained personnel and can have a long time to result. These requirements can be alleviated using paper-based diagnostic devices that enable rapid and inexpensive diagnosis at the point of care, which can allow patients to receive treatment before their symptoms progress when used for early detection of diseases. The lateral-flow immunoassay (LFA) is one such device, but currently available LFAs are susceptible to false negative results caused by low parasite density. To improve sensitivity and detection, we utilized the aqueous two-phase system (ATPS) to concentrate and purify the sample, and nanozyme signal enhancement to increase the intensity of the visible signal on the test strip. We were able to achieve a limit of detection (LOD) of 0.01 ng/mL for the malaria biomarker Plasmodium lactate dehydrogenase (pLDH) in human serum using a multi-step assay combining the LFA format with the ATPS and nanozyme signal enhancement.

Point-of-Need Diagnostics for Foodborne Pathogen Screening.

Foodborne illness is a major public health issue that results in millions of global infections annually. The burden of such illness sits mostly with developing countries, as access to advanced laboratory equipment and skilled lab technicians, as well as consistent power sources, is limited and expensive. Current gold standards in foodborne pathogen screening involve labor-intensive sample enrichment steps, pathogen isolation and purification, and costly readout machinery. Overall, time to detection can take multiple days, excluding the time it takes to ship samples to off-site laboratories. Efforts have been made to simplify the workflow of such tests by integrating multiple steps of foodborne pathogen screening procedures into a singular device, as well as implementing more point-of-need readout methods. In this review, we explore recent advancements in developing point-of-need devices for foodborne pathogen screening. We discuss the detection of surface markers, nucleic acids, and metabolic products using both paper-based and microfluidic devices, focusing primarily on developments that have been made between 2015 and mid-2020.