Dongmin Kim

With the accelerating expansion of connectivity, the need for advanced cyber-physical security technologies that bridge the digital and physical worlds is becoming more crucial than ever. Physically unclonable functions (PUFs) leveraging nanotechnologies and photonic technologies are emerging as practical and deployable hardware security solutions that go beyond software-based hardware security. Optics- and photonics-based PUFs (often referred to as optical PUFs) offer a range of characteristics beneficial to multiplex strategies that incorporate multilevel and multimodal approaches, based on their fundamental optical and photonic properties. PUFs are categorized as multilevel when multiple responses are generated from a single type of challenge, such as a light source or optical tool. In contrast, they are classified as multimodal when multiple responses are created from various types of challenges involving a combination of different light sources and optical tools. This review highlights recent advances and progress in integrating emerging materials, detection tools, authentication methods, imaging techniques, reconfigurability, and unclonability, which are essential for advancing next-generation multiplex PUFs. To facilitate real-world applications and to support deployment in real-world senarios, we also discuss existing limitations in multiplex optical PUFs and explore potential strategies to overcome such challenges, supporting our increasingly hyperconnected society.

Currently, polypropylene (PP) is used in various products, thus leading to high daily exposure in humans. Thus, it is necessary to evaluate the toxicological effects, biodistribution, and accumulation of PP microplastics in the human body. In this study, administration of two particle sizes of PP microplastics (approximately 5 and 10–50 µm) did not lead to any significant changes in several toxicological evaluation parameters, including body weight and pathological examination, compared with the control group in ICR mice. Therefore, the approximate lethal dose and no-observed-adverse-effect level of PP microplastics in ICR mice were established as ≥2000 mg/kg. Furthermore, we manufactured cyanine 5.5 carboxylic acid (Cy5.5-COOH)-labeled fragmented PP microplastics to monitor real-time in vivo biodistribution. After oral administration of the Cy5.5-COOH-labeled microplastics to the mice, most of the PP microplastics were detected in the gastrointestinal tract and observed to be out of the body after 24 h in IVIS Spectrum CT. Therefore, this study provides a new insight into the short-term toxicity, distribution, and accumulation of PP microplastics in mammals.