Recent approaches for optical smartphone sensing in resource-limited settings: A brief review

Developments in the emerging fields of smartphone chemical and biosensing have dovetailed with increased interest in environmental and health monitoring for resource-limited environments, culminating in research toward field-ready smartphone sensors. Optical sensors have been a particular focus, in which smartphone imaging and on-board analysis have been integrated into both existing and novel colorimetric, fluorescent, chemiluminescent, spectroscopy-based, and scattering-based assays. Research in recent years has shown promising progress, but substantial limitations still exist due to environmental lighting interference, reliance upon proprietary smartphone attachments, and the undefined sensitivity variations between different smartphones. In this review, recent research in smartphone chemical and biosensing is assessed, and discussion is made regarding the opportunities that new research methods have to improve the scope of resource-limited sensing.