Uses and occurrences of five major alternative plasticizers, and their exposure and related endocrine outcomes in humans: A systematic review

Non-phthalate plasticizers are being increasingly used in commercial and consumer products, to replace phthalates. Among major non-phthalate plasticizer groups, we chose five alternative plasticizers of DEHA, DINCH, DEHTP, ATBC, and TOTM, and conducted a systematic literature review for current knowledge on their use and occurrences in major sources, and their exposure and endocrine outcomes in humans. Relevant articles published between January 2000 and December 2022 were identified from PubMed and Scopus search and analyzed. For occurrence, biomonitoring, and endocrine-related outcomes, 79, 73, and 14 studies were finally identified, respectively. The alternative plasticizers were widely used in food packaging, children’s products, hygiene products, medical devices, and construction materials, and frequently detected in indoor dust. Food packaging materials and children’s products were major sources of direct exposure to humans. Human exposure to alternative plasticizers is reported mostly via biomonitoring of urine. Urinary levels of DEHTP and DINCH metabolites were higher among infants, children, and pregnant women than in general adults. In humans, DEHTP, DINCH, or ATBC exposure were associated with sex hormone disruption and reproductive outcomes, but these associations varied by sex and age. This review showed that the use of and exposure to these alternative plasticizers have increased over time. Their potential health implications, especially among susceptible humans, warrant greater attention and further investigation.</p

Fluorogenic Quantum Dot-Gold Nanoparticle Assembly for Beta Secretase Inhibitor Screening in Live Cell

We have developed a novel fluorogenic nanoprobe prepared from the assembly of CdSe/ZnS quantum dot (QD) and gold (Au) nanoparticles in which QD was conjugated with a specifically designed β-secretase (BACE1) substrate peptide, which was allowed to bind to the Ni-nitrilotriacetate (Ni-NTA) modified Au nanoparticles. This coordination-mediated binding of the QD with Au nanoparticles via Ni-NTA-histidine (His) interaction resulted in highly efficient quenching of QD fluorescence through a distance-dependent fluorescence resonance energy transfer (FRET) phenomenon. The prequenched QD-Au assembly recovered the fluorescence in the presence of the BACE1 enzyme after incubation in vitro. The high quenching efficiency of AuNP and robust QD fluorescence signal recovery upon BACE1 enzymatic digestion enabled us to visualize BACE1 activity in living cells, which further allowed us to generate the half maximal inhibitory concentration (IC₅₀) values for BACE1 inhibitors in the cell-based assay utilizing a high throughput system (HTS). These results suggest the potential application of QD-AuNP assembly toward the HTS drug screening system as a robust and efficient probe to identify active molecules in BACE1-related diseases such as Alzheimer’s disease