We describe progress towards developing a low-cost, simple, and compact imaging system for Digital Bead Assays (DBA) for use in Point-of-Care (POC) diagnostic systems. DBA — such as digital ELISA using single molecule arrays (Simoa) — have emerged as a key advance for the sensitive detection of proteins down to attomolar concentrations, i.e., single-digit numbers of proteins in a droplet of blood or another clinical sample. These assays have enabled unique clinical research and diagnostic measurements, e.g., the measurement in blood of protein biomarkers of neurological conditions, enabling “blood tests for the brain” that can detect Alzheimer’s disease 16 years before dementia symptoms arise. For DBA to have its maximum impact on society, it must be available in low-cost, compact equipment that can be used by anyone around the world. For this goal to become a reality, low-cost and simple imaging systems are needed. In this paper, we will describe a concept for a low-cost, simple, and compact DBA imager. We will describe evaluation of low-cost optics — such as cell-phone optics — and cameras, and how image analysis methods can be used to generate useful data from the lower resolution images provided by these systems.
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