Approaches to Nanoparticle Labeling:A Review of Fluorescent,Radiological,and Metallic Techniques

Nanomaterials are widely used in commercial products,resulting in the release of nanoscale particles into the environment.This raises concerns about their potential exposure risks in complex biological matrices.Most attempts use engineered nanomaterials(ENMs)to mimic the biological behavior of nanoparticles in the environment,and labeling of ENMs by sensors is a commonly used approach for sensitive detection and tracking of ENMs in organisms.However,due to the distinct physicochemical properties of nanoparticles,different labeling approaches have been developed,each with varying applicability.In this Review,we summarize the three main types of labeling methods used for nanoparticles:fluorescent,radiological,and metallic labeling.We discuss their labeling mechanisms,efficiency,stability,target nanoparticles,and applicability in different organism models.Finally,we propose a labeling scheme for specific nanoparticles.Overall,this Review provides a comprehensive overview of the advances in nanoparticle labeling techniques and their potential applications in environmental and health studies.

Antibacterial applications of graphene oxides: structure-activity relationships, molecular initiating events and biosafety

Bacterial infections may lead to diverse acute or chronic diseases(e.g., inflammation, sepsis and cancer).New antibiotics against bacteria are rarely discovered in recent years, which necessitates the exploration of new antibacterial agents. Engineered nanomaterials(ENMs) have been extensively studied for antibacterial use because of their long lasting killing effects in wide spectra of bacteria. Graphene oxide(GO) is one of the most widely studied ENMs and exhibit strong bactericidal effects. The physicochemical properties of GO play important roles in bacterial killing by triggering a cascade of toxic events. Many studies have explored the signaling pathways of GO in bacteria. Although molecular initiating events(MIEs) of GO in bacteria dominate its killing efficiency as well as toxicity mechanisms, they have been rarely reviewed. In this report, we discussed the structure–activity relationships(SARs) involved in GOinduced bacterial killing and the MIEs including redox reaction with biomolecules, mechanical destruction of membranes and catalysis of extracellular metabolites. Furthermore, we summarized the clinical or commercial applications of GO-based antibacterial products and discussed their biosafety in mammal.Finally, we reviewed the remaining challenges in GO for antibacterial applications, which may offer new insights for the development of nano antibacterial studies.