Counterfeiting of financial cards and marketable securities is a major social problem globally. Electronic identification and image recognition are common anti-counterfeiting techniques, yet they can be overcome by understanding the corresponding algorithms and analysis methods. The present work describes a physically unclonable functions taggant, in an aqueous-soluble ink, based on surface-enhanced Raman scattering of discrete self-assemblies of Au nanoparticles. Using this stealth nanobeacon, we detected a fingerprint-type Raman spectroscopy signal that we clearly identified even on a business card with a pigment mask such as copper-phthalocyanine printed on it. Accordingly, we have overcome the reverse engineering problem that is otherwise inherent to analogous anti-counterfeiting techniques. One can readily tailor the ink to various information needs and application requirements. Our stealth nanobeacon printing will be particularly useful for steganography and provide a sensitive fingerprint for anti-counterfeiting.
The globalization of drug trade has led to the increased production of falsiˆed medicines. In addition, poor medication adherence increases the costs of healthcare. The need to manage medication has given rise to marketing of highly functional networked digital medicine. Therefore, a growing need has emerged to ensure the traceability of pharmaceutical products from shipment to patient distribution. Microtaggant technologies that can encode individual numbers on pharmaceutical products are expected to serve achieving this goal. Taggants are a class of materials that can be applied to an object to make it identiˆable, like barcodes and holograms. Since the smaller size of microtaggant make it invisible to naked eyes, it is more di‹cult to reverse-engineer than conventional taggants. The U.S. Food and Drug Administration (FDA) has established guidelines for the use of microtaggants. Many studies have explored the use of various analytical technologies and materials as the microtaggants. However, the advantages and disadvantages of each method have not been established yet. In this review, recent research on the use of microtaggants for anti-counterfeiting is summarized and compared to current anti-counterfeiting technologies with spectrographic methods, distribution management systems with barcodes, and medication management systems with sensor devices. We also discuss the microtaggants implementation costs and security level.
Plasmonic nanomaterials have attracted much attention to new anticounterfeiting technology. Since one of current anticounterfeiting problems is fake medical tablets, on-dose authentication of the tablets is strongly required considering tiny area of tablets, biocompatibility, and long shelf life. Previously, Nanotags consisting of self-assemblies of colloidal gold nanoparticles with reporter molecules were proposed, which produce characteristic surface enhanced Raman scattering (SERS) activity. However, long-term stability is rarely discussed for SERS active nanostructures. This study deposits about 10 ng of the Nanotags on a very tiny area of the commercial tablets. Distinguishable SERS signals of reporting molecules are confirmed by 1s irradiation of 785 nm laser over the Nanotags, while Raman spectrum of the ingredients is observed on the tablet without the Nanotags. Rapid authentication of tablets stocked over 8 years is sufficiently carried out. In addition, the Nanotags on the tablets are almost invisible to the eye, in particular, if the tablet surface is uneven or colored. It is considered that the presence of discrete AuNP assemblies allows excellent performances of Nanotag.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.