Comparison of nanowire pellicles for plasma membrane enrichment: coating nanowires on cell

A study is reported on the effect of nanowire density on the ease of pellicle formation and the enrichment of plasma membrane proteins for analysis by mass spectrometry. An optimized synthesis is reported for iron silicate nanowires with a narrow size range of 900 ±400 nm in length and 200 nm diameter. The nanowires were coated with Al₂O₃ and used to form pellicles around suspended multiple myeloma cells, which acted as a model for cells recovered from tissue samples. Lighter alumina-coated silica nanowires were also synthesized (Kim et al. 2013), which allowed a comparison of the construction of the two pellicles and of the effect of nanowire density on plasma membrane enrichment. Evidence is offered that the dense nanowire pellicle does not crush or distort these mammalian cells. Finally, the pellicles were incorporated into a mass-spectrometry-based proteomic workflow to analyze transmembrane proteins in the plasma membrane. In contrast to a prior comparison of the effect of density with nanoparticles pellicles (Choksawangkarn et al. 2013), nanowire density was not found to significantly affect the enrichment of the plasma membrane. However, nanowires with a favorable aspect for pellicle formation are more easily and reliably produced with iron silicate than with silica. Additionally, the method for pellicle formation was optimized through the use of iron silicate nanowires (ISNW), which is crucial to the improvement of PM protein enrichment and analysis.