Evaluating the antibacterial property of gold-coated hydroxyapatite: a molecular biological approach

UV-aging of microplastics increases proximal ARG donor-recipient adsorption and leaching of chemicals that synergistically enhance antibiotic resistance propagation

Despite growing attention to environmental pollution by microplastics (MP), the effects of MP aging on bacterial horizontal gene transfer (HGT) have not been systematically investigated. Here, we used UV-aged polystyrene microplastics (PS-MPs) to investigate how aging affects antibiotic resistance genes (ARGs) transfer efficiency from various ARG vectors to recipient bacteria. The adsorption capacity of MP₂₀ (20-day UV-aged PS-MPs) towards E. coli (harboring plasmid-borne bla_TEM-1), plasmid pET29 (harboring bla_NDM-1) and phage lambda (carrying the aphA1 ARG) increased by 6.6-, 5.2- and 8.3-fold, respectively, relative to pristine PS-MPs (MP₀), due to increased specific surface area and affinity for these ARG vectors. Moreover, MP₂₀ released more organic compounds (TOC 1.6 mg/g-MP₂₀, versus 0.2 mg/g-MP₀ in 4 h) -possibly depolymerization byproducts (verified by GC-MS), which induced intracellular ROS generation, increased cell permeability and upregulated HGT associated genes. Accordingly, MP₂₀ enhanced ARG transfer frequency from E. coli, plasmid pET29 and phage lambda (relative to MP₀) by 1.3-, 4.7- and 3.5-fold, respectively. The Bliss independence model infers that higher bacterial adsorption and exposure to chemicals released during MP aging synergistically enhanced ARG transfer. This underscores the need to assess the significance of this overlooked phenomenon to the environmental dissemination of antibiotic resistance and other HGT processes.

Three-dimensional, sharp-tipped electrodes concentrate applied fields to enable direct electrical release of intact biomarkers from cells

Biomarkers such as proteins and nucleic acids released from human cells, bacteria, and viruses offer a wealth of information pertinent to diagnosis and treatment ranging from cancer to infectious disease. The release of these molecules from within cells is a crucial step in biomarker analysis. Here we show that purely electric-field-driven lysis can be achieved, inline, within a microfluidic channel; that it can produce highly efficient lysis and biomarker release; and, further, that it can do so with minimal degradation of the released biomarkers. Central to this new technology is the use of three-dimensional sharp-tipped electrodes (3DSTEs) in lysis, which we prove using experiment and finite-element modeling produce the electric field concentration necessary for efficient cell wall rupture.