To date, various techniques have been developed and have refined over the years to measure CTFs of single cells or population of cells, including cell-populated collagen gel method [13], micromechanical cantilever beam-based force sensor array [14], cell traction force microscopy [15], and elastomeric micropost array [16, 17]. In 2009, Li et al. reported another

favorable method to quantify the traction force of a single cell by aligned silicon nanowire (SiNW) arrays [18]. They reported that the CTFs of the cells cultured on this SiNW arrays could be calculated from these underlying SiNW deflections. However, no further lateral Napabucasin chemical structure CTF information (cross-sectional) inside the cell underlying on the nanotopographic substrates was provided. In this letter, we first report on direct observations of the primary mouse CD4 T cell morphologies by culturing CD4 T cells on streptavidin (STR)-functionalized quartz nanopillar arrays (QNPA) using a scanning electron microscopy (SEM) method and then demonstrate a new alternative selleckchem technique to measure cross-sectional cell traction force distribution of surface-bound CD4 T cells including those inside the cells on QNPA substrates by culturing the cells on the top of the QNPA and further analysis in deflection of underlying QNPA via focused ion beam (FIB)-assisted selleck products technique. It conducted both a high-performance etching and imaging scheme

from FIB and finite element method (FEM)-based computer simulation tools with well-defined QNPA substrates. We suggest that the use of the FIB-based technique combined with QNPA and FEM simulation would be a powerful and fine process to evaluate cross-sectional CTFs of single cells. Methods Figure 1a,b shows a schematic illustration of QNPA fabrication processes and further surface functionalization Y-27632 2HCl processes, respectively. First, the fabrication process went through a series of process including polystyrene (PS) monolayer deposition, PS size reduction, Ni metal deposition, PS lift-off, additional Cr metal deposition, Ni lift-off, and final reactive ion etching process we have improved previously

[19, 20]. In addition, the surface of QNPA substrates treated by O2 plasma was then applied by three-step surface functionalization processes using 1% (v/v) (3-aminopropyl)-triethoxysilane (APTES) in ethanol for 30 min at room temperature, 12.5% (v/v) glutaraldehyde (GA) in distilled water for 4 h on a 2D rocker, and approximately 50-μg/mL STR solution in phosphate buffered saline (PBS) overnight in an incubator (37°C, 5% CO2). We used this surface-functionalized method on nanotopographic substrates to separate targeting specific cells (e.g., CD4 T cells) among different kinds of cells via the novel STR-biotin conjugation technique to capture the incoming targeting cells in PBS solution as we have developed previously [20, 21].