Novel Streptavidin-Functionalized Silicon Nanowire Arrays for CD4⁺ T Lymphocyte Separation

Abstract

Silicon nanowires (SiNWs) offer promising inorganic nanostructures for biomedical application. Here, we report the development of a novel SiNW array designed for isolating primary CD4(+) T lymphocytes from the heterogeneous mixture of cell populations. Our system employed the specific high-affinity binding features of streptavidin (STR)-functionalized SiNW with biotin-labeled CD4(+) T lymphocytes. Fabricated SiNW arrays easily separated the CD4(+) T lymphocytes from the mouse whole splenocytes with over approximately 88% purity and demonstrated tight attachment to CD4(+) T lymphocytes by scanning electron microscopy. Thus, our STR-SiNW arrays provide a potential tool for specific cell separation and further present a possibility to be applied to the other area of biomedical applications.

Morphology of CD4+T Lymphocytes Bound on Nano-Patterened Substrates for Sensing the Size of Nanoholes

“…4b exhibits that the extended filopodia of the captured CD4 + T-cells were observed to increase in width by increasing the diameter of QNHA from 140 to 550 nm, resulting in a good linear response between the width of T-cells and diameter of QNHA (R 2 =0.959, n=10). These results suggest that the microvilli (filopodia or lamellipodia) of CD4 + T-cells closely react with the QNHA substrates via high-affinity STR-biotin conjugation [7] as we proved previously and extend filopodia of different lengths or widths depending on the diameter of the QNHAs as an alive sensor system to detect the size of the structures underneath of the cells using microvilli (Figs. 3a-l).…”

“…These splenocytes were prepared from the spleens of C57BL/6/mice as described previously [7]. Prior to loading the cell suspension containing certain quantity of cells (~10 5 cells/mL) in the culture medium onto the QNHA substrates, the cell population with a final volume of ~30 °was first reacted with biotinylated anti-CD4 mAb and incubated at 4 o C for 20 min.…”

“…The T-cells were first fixed with 4% GA in the refrigerator for 2 hr, followed by a post-fix process using 1% osmium tetroxide for 2 hr. The captured T-lymphocytes were then dehydrated through a series of ethanol concentrations (25, 50, 75, 95, and 100%) and slowly dried at vacuum-connected desiccators for 24 hr [7,9]. Once the samples were dry in the desiccators, the surface-bound T-lymphocytes were sputter-coated with platinum before performing the FE-SEM measurement.…”

“…Furthermore, nanostructures have been increasingly used for studies on cell interaction with solid nanostructures because unique properties of nanostructured surfaces enable a variety of novel functions of immobilized cells on the nanostructured surfaces [4,5]. To date, these nanostructures were prepared by various methods including the polymeric templating method [6], vaporliquid-solid (VLS) growth [7], dry-etching process using nanosphere lithography technique [8,9]. Recently, we have also demonstrated a novel platform for separating CD4 + T lymphocytes from mouse splenocytes using streptavidin (STR)-functionalized and vapor-liquid-solid (VLS)-grown silicon nanowire (SiNW) [7] as well as transparent quartz nanopillar (QNP) arrays [8,9] having a higher separation efficiency of 93-95.3%.…”

“…To date, these nanostructures were prepared by various methods including the polymeric templating method [6], vaporliquid-solid (VLS) growth [7], dry-etching process using nanosphere lithography technique [8,9]. Recently, we have also demonstrated a novel platform for separating CD4 + T lymphocytes from mouse splenocytes using streptavidin (STR)-functionalized and vapor-liquid-solid (VLS)-grown silicon nanowire (SiNW) [7] as well as transparent quartz nanopillar (QNP) arrays [8,9] having a higher separation efficiency of 93-95.3%. However, there is no study on how the various size and shape-matched nanostructures and nanomaterials interact in the primary cells on the nanostructured substrates.…”