The team examined the biofilm using transmission electron microscopy at Berkeley Lab’s National Center for Electron Microscopy, a national user facility that probes material at the nanoscale. They found that the zinc sulfide nanoparticles were arranged in dense aggregates. Such tightly packed metal sulfide formations are not new to scientists, but they do beg a question that remains unanswered: Why do the nanoparticles group together" Something so small should disperse throughout the mine. Instead, the metal nanoparticles form blobs that measure several microns in diameter (one micron is one-millionth of a meter). And these larger blobs anchor the nanoparticles in place. Stopping nanoparticles in their tracks, as this process does, could become a critical component of a bioremediation strategy, if only scientists understand how it works.
To explore this question, the team turned to Berkeley Lab’s Advanced Light Source, a national user facility that generates intense light for scientific research. Using an imaging tool called Fourier-transform infrared spectroscopy, the team analyzed the zinc sulfide aggregates and detected the characteristic signal of proteins.
Next, to further zero in on this intriguing signal, they examined the sample using an extremely high-spatial-resolution imaging tool called secondary ion probe spectrometry, which is located at the Department of Energy’s Lawrence Livermore National Laboratory. Also called NanoSIMS, the tool determines the quantitative elemental and isotopic composition of a sample’s surface.
To their surprise, they found proteins and polypeptides embedded within the zinc sulfide nanopar
Source:DOE/Lawrence Berkeley National Laboratory