The disclosure relates to the use of nanoparticles that are coated with unique oligonucleotide (e.g., DNA) sequences of various base lengths (“nano-DNA”) that act as barcodes for product authentication, product serialization, brand protection, track-and-trace, intelligent supply chain, and law enforcement. The nano-DNA can be incorporated into inks, dyes, resins, labels, and other markings at all manufacturing levels, including the product (unit) level, to encode company and product-specific information. The nano-DNA can also be embedded in the product itself during the manufacturing process. Furthermore, the nano-DNA can be quickly, simply, and inexpensively monitored and verified using an electrochemical biosensor device in resource-limited field conditions.