We use a microfluidic cell culture chip equipped with pneumatic microvalves to analyze the paracrine loop between lung cancer cells and fibroblasts. In order to assess the cellular responses in the paracrine loop, we measure the migration speeds of cancer cells and the aspect ratios of fibroblasts which reflect the phenotype of myofibroblasts. With well-controlled interaction sequences between these two types of cells, we verify that the cytokines from cancer cells effectively stimulate the fibroblasts into myofibroblasts. The cytokines from myofibroblasts, rather than fibroblasts, increase the migration speeds of cancer cells. We confirm that the transforming growth factor-β1 (TGF-β1) is involved in the interaction between cancer cells and fibroblasts, and we also interrupt this paracrine loop in the cell culture chip by inhibiting the TGF-β1 receptors on fibroblasts.

We employ a microfluidic chip with three culture chambers to investigate the interactions among lung cancer cells, macrophages and myofibroblasts. By mixing the conditioned media of macrophages and myofibroblasts in this chip, we confirm that these two stromal cells have synergistic effects in accelerating the migration of cancer cells. However, as the myofibroblasts are pretreated with the conditioned medium of macrophages, the myofibroblasts' ability to enhance the migration of cancer cells is lowered. The tumour necrosis factor-α produced by macrophages reduces the expression of α-smooth muscle actin and the secretion of transforming growth factor-β1 in myofibroblasts. Once the tumour necrosis factor-α in the macrophage conditioned medium is neutralized, the macrophage medium-pretreated myofibroblasts can still accelerate the migration of cancer cells.

Increasing the hot-spot area with high enhancement ability on SERS-active particles is generally acknowledged as one of the efficient ways to significantly improve the average SERS signal of nanoparticles. A method to create roughness on the surface of nanoparticles was proposed by oxygen plasma etching noncarboxylated polystyrene beads. However, the mechanism of nanocorrugation formation was not clear. Thus, in this paper, we employ argon-based reactive ion etching (RIE) incorporated with carboxylated polystyrene nanoparticles to investigate the roles of nanocorrugations’ morphologies for SERS signal enhancement. The formation mechanism of the nanocorrugations has been investigated thoroughly through a comparison with those formed by oxygen-based RIE processes from their high resolution X-ray photoelectron spectra and surface morphologies with or without hydrazine reduction treatment. Moreover, polystyrene beads with more intrinsic carboxyl groups and etched by argon plasma produce higher nanocorrugations. It is suggested that carbonyl groups with high bond energy become nanomasks on polystyrene bead surfaces and provides high selectivity between carboxyl and polystyrene surfaces under RIE. Raman intensity enhancement on a 20-nm gold coated nanocorrugated polystyrene bead array is summarized by three factors: (1) the effect of plasmonic coupling among neighboring particles, (2) the nanocorrugation-contributed roughness, and (3) the pitch size of nanocorrugations, through the analysis of SEM images, AFM height images, and LSPR signals. Among these factors, the pitch size of nanocorrugations (ranging from ∼6 nm to ∼12 nm on the surface of polystyrene beads) dominates the SERS enhancement. The 870 nm/120s oxygen plasma etched polystyrene beads (OPSBs) with a minimum pitch size of 6 nm provides the highest Raman intensity enhancement (measured by 632.8-nm He–Ne laser), which is 12 times greater than the intensity of nontreated (870 nm/0s) polystyrene beads (while the Au/Ti coating is 20 nm/5 nm).

We explore the dynamics of cancer cell filopodia of diameters around 200 nm by using super-resolution bright-field optical microscopy. The high contrast required by the super-resolution image-restoration process is from the nanometer topographic sensitivity of non-interferometric widefield optical profilometry, rather than fluorescence labeling. Because the image-acquisition rate of this bright-field system is 20 frames/min, fast cellular dynamics can be captured and then analyzed. We successfully observe the growth and activities of the filopodia of a CL1-0 lung cancer cell. In the culturing condition, we measure that the filopodia exhibit an average elongation rate of 90 nm/sec, and an average shrinkage rate of 75 nm/sec. With the treatment of epidermal growth factor, the elongation and shrinkage rates increase to 110 nm/sec and 100 nm/sec respectively. We also find that the treatment of epidermal growth factor raises the number of filopodia by nearly a factor of 2, which implies enhancement of cell motility.

Abstract. The membrane roughness of Neuro-2a neroblastoma cells is measured by using noninterferometric widefield optical profilometry. The cells are treated with the fibril and oligomer conformers of amyloid-beta (Aβ) 42, which is a peptide of 42 amino acids related to the development of Alzheimer's disease. We find that both the Aβ42 fibrils and Aβ42 oligomers reduced the cell membrane roughness, but the effect of Aβ42 oligomers was faster and stronger than that of the fibrils. We also apply direct-current electric field (dcEF) stimulations on the cells. A dcEF of 300 mV∕mm can increase the membrane roughness under the treatment of Aβ42. These results suggest that Aβ42 can decrease the membrane compliance of live neuroblastoma cells, and dcEFs may counteract this effect. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

We used a liquid-crystal spatial light modulator to project 473 nm light patterns surrounding a region of adherent cells and achieved an arbitrarily micropatterned cell culture. For a group of ∼60 cells, the cell boundaries fit the pattern of light within 15% deviation of the side length. We also demonstrated a wound-healing experiment with a definite starting temporal point by using this technique. While observing mitochondrial structures in the illuminated cells, we found that the 473 nm light damaged the integrity of mitochondria and thus prohibited cell proliferation in the illuminated region.

We employ 405 and 1064 nm laser light to perturb the motions of lung cancer cell lamellipodia. The 405 nm light causes lamellipodial retractions while the 1064 nm light enhances protrusions. With the observation of actin distributions in the lamellipodia, we find that the 1064 nm laser light increases the density of actin near the illuminated site, while the 405 nm light reduces the actin distribution.

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