Silver nanoparticles (AgNPs) have become one of the most popular objects of study for the past few decades. The ability to design AgNPs through different synthetic methods according to the application area and desired features is their advantage in many applications. Green synthesis of silver nanoparticles has become one of the most potential synthesis methods. Because of their strong antibacterial activity, AgNPs have been used in a wide range of applications, such as food packaging and medical products and devices. With the increasing application of AgNPs, it is becoming necessary for a better understanding of the toxicity of AgNPs and their potential mechanism of toxicity. In the review, we first describe the synthetic methods of AgNPs. The application of AgNPs in the field is then briefly described. The toxicity of AgNPs and their potential toxicity mechanisms are discussed.

Highly luminescent quantum dot beads (QBs) were synthesized by encapsulating CdSe/ZnS and used for the first time as immunochromatographic assay (ICA) signal amplification probe for ultrasensitive detection of aflatoxin B₁ (AFB₁) in maize. The challenges to using high brightness QBs as probes for ICA are smooth flow of QBs and nonspecific binding on nitrocellulose (NC) membrane, which are overcome by unique polymer encapsulation of quantum dots (QDs) and surface blocking method. Under optimal conditions, the QB-based ICA (QB-ICA) sensor exhibited dynamic linear detection of AFB₁ in maize extract from 5 to 60 pg mL^–1, with a median inhibitory concentration (IC₅₀) of 13.87 ± 0.16 pg mL^–1, that is significantly (39-fold) lower than those of the QD as a signal probe (IC₅₀ = 0.54 ± 0.06 ng mL^–1). The limit of detection (LOD) for AFB₁ using QB-ICA sensor was 0.42 pg mL^–1 in maize extract, which is approximately 2 orders of magnitude better than those of previously reported gold nanoparticle based immunochromatographic assay (AuNP-ICA) and is even comparable with or better than the conventional enzyme-linked immunosorbent assay (ELISA) method. The performance and practicability of our QB-ICA sensor were validated with a commercial ELISA kit and further confirmed with liquid chromatography tandem mass spectrometry (LC–MS/MS). Given its efficient signal amplification performance, the proposed QB-ICA offers great potential for rapid, sensitive, and cost-effective quantitative detection of analytes in food safety monitoring.

Nanoparticles (NPs) size, surface functionalization, and concentration were claimed to contribute to distribution and toxicity outcomes of NPs in vivo. However, intrinsic chemical compositions of NPs caused inconsistent biodistribution and toxic profiles which attracted little attention. In this study, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were used to determine the biodistribution, toxickinetic, and genotoxicity variances in murine animals. The results demonstrated AgNPs and AuNPs were primarily deposited in the mononuclear phagocyte system (MPS) such as the liver and spleen. In particular, AuNPs seemed to be prominently stored in the liver, whereas AgNPs preferentially accumulated in more organs such as the heart, lung, kidney, etc. Also, the circulation in the blood and fecal excretions showed higher AgNPs contents in comparison with the AuNPs. Measurements of the mouse body and organ mass, hematology and biochemistry evaluation, and histopathological examinations indicated slight toxic difference between the AgNPs and AuNPs over a period of two months. RT-qPCR data revealed that AgNPs induced greater changes in gene expression with relevance to oxidative stress, apoptosis, and ion transport. Our observations proved that the NPs chemical composition played a critical role in their in vivo biodistribution and toxicity.