Aging Characteristics and Ecological Effects of Primary Microplastics in Cosmetic Products Under Different Aging Processes.

Microplastics are becoming an increasingly environmental concern, but only a few studies have focused on primary microplastics. Herein, four primary microplastics (Lapis, Jade, Topaz and White) commonly used in cosmetic products were selected to investigate the effects of sunlight, seawater, and soil aging on their environmental behaviors. After sunlight and seawater aging, the surfaces of all four microplastics developed breaks and cracks, with particle sizes decreased and specific surface areas increased. Topaz exhibited the most significant changes under sunlight and seawater aging and its maximum adsorption capacity of phenanthrene significantly increased by 22.50% and 47.86%, respectively. Under soil aging, amending with either White or Topaz changed the soil bacterial community composition and diversity, but they had less ecological impacts than polyvinyl chloride plastic. The results of this study provide vital information for understanding the aging characteristics, environmental behavior, and ecological effects of primary microplastics under natural aging processes.

UV-Irradiation Facilitating Pb Release from Recycled PVC Microplastics.

Microplastics (MPs) are ubiquitously in ecosystem and have evoked wide attention. The potential risk of MPs to the ecosystems is associated with MPs and the additives such as Pb, which serves as a traditional stabilizer. However, the release of Pb from MPs remains largely unknown. In this study, we evaluated the release of Pb from recycled polyvinyl chloride (PVC) under UV-irradiation. The release process was dominated by two processes: H+ facilitated dissolution of Pb, and light-induced hydroxyl radical (·OH) caused C-H bond cleavage from PVC with the generation of alkyl radical. The effects of pH and coexisting low molecular weight organic acids (LMWOAs) were also evaluated. Lower pH speeds up the Pb release from MPs. The LMWOAs act as a filter of UV to restrain the Pb release. Overall, this study shows the release of Pb from recycled PVC MPs and indicates the potential risk of Pb to the environment.

Characterizing Bioinks for Extrusion Bioprinting: Printability and Rheology.

In recent years, new technologies based on 3D bioprinting have emerged as ideal tools with which to arrange cells and biomaterials in three dimensions and so achieve tissue engineering's original goals. The simplest and most widely used form of bioprinting is based on pneumatic extrusion, where 3D structures are built up by drawing patterns of cell-laden or non-cell-laden material through a robotically manipulated syringe. Developing and characterizing new biomaterials for 3D bioprinting (i.e., bioinks) is critical for the progress of the field. This chapter describes a series of protocols for developing, optimizing, and testing new bioinks for extrusion-based 3D bioprinting.