This invention discloses a signal amplification sandwich structure for amplifying detection signals from proteins, nucleic acids and microbes using a plurality of an electrochemically detectable oligonucleotide tag bound to a multifunctional particle. The invention further discloses a method and device that uses the signal amplification sandwich structure to detect and/or quantify low levels of one or more biological analytes using an off-the-shelf point-of-care electrochemical potentiostat, like a glucose meter for virtually any biological analyte. The invention further discloses a method and device that applies an artificial intelligence (AI) system to recommend actions for assessment and diagnosis of a disease, outbreak or condition with an artificial intelligence learning system to incorporate improvements, additions and modifications to the artificial intelligence systems and its constituents.