In this paper, large-area magnetic–plasmonic Ni@Au core–shell nanoparticle arrays (NPAs) with tunable compositions were successfully fabricated by a direct laser interference ablation (DLIA) incorporated with thermal dewetting method. The magnetic properties of the Ni@Au core–shell NPAs were analyzed and the saturation magnetization (M_s) of the Ni₈₀@Au₂₀ nanoparticles was found to be higher than that of nickel-only nanoparticles with the same diameter. Using Rhodamine 6G (R6G) as a Raman reporter molecule, the surface enhanced Raman scattering (SERS) property of the Ni@Au core–shell NPAs with a grain size distribution of 48 ± 42 nm and a short-distance order of about 200 nm was examined. A SERS enhancement factor of 2.5 × 10⁶ was realized on the Ni₅₀@Au₅₀ NPA substrate, which was 9 times higher than that for Au nanoparticles with the same size distribution. This was due to the enhanced local surface plasmon resonance (LSPR) between the ferromagnetic Ni cores and the surface polariton of the Au shells of each nanoparticle. The fabrication of the Ni@Au core–shell NPAs with different compositions offers a new avenue to tailor the optical and magnetic properties of the nanostructured films for chemical and diagnostic applications.

The stiffness and the topography of the substrate at the cell–substrate interface are two key properties influencing cell behavior. In this paper, atomic force acoustic microscopy (AFAM) is used to investigate the influence of substrate stiffness and substrate topography on the responses of L929 fibroblasts. This combined nondestructive technique is able to characterize materials at high lateral resolution. To produce substrates of tunable stiffness and topography, we imprint nanostripe patterns on undeveloped and developed SU-8 photoresist films using electron-beam lithography (EBL). Elastic deformations of the substrate surfaces and the cells are revealed by AFAM. Our results show that AFAM is capable of imaging surface elastic deformations. By immunofluorescence experiments, we find that the L929 cells significantly elongate on the patterned stiffness substrate, whereas the elasticity of the pattern has only little effect on the spreading of the L929 cells. The influence of the topography pattern on the cell alignment and morphology is even more pronounced leading to an arrangement of the cells along the nanostripe pattern. Our method is useful for the quantitative characterization of cell–substrate interactions and provides guidance for the tissue regeneration therapy in biomedicine.

Although nanopillars (NPs) provide a promising tool for capturing tumor cells, the effect of mixing NPs with other nanopatterns on cell behavior remains to be further studied. In this paper, a method of fabricating silicon nanoscale topographies by combining laser interference lithography with metal assisted chemical etching was introduced to investigate the behaviors and pseudopodia of A549 cells on the topologies. It was found that cells had a limited manner in spreading with small cell areas on the silicon nanopillar (SiNP) arrays, but a good manner in spreading with large cell areas on the silicon nanohole (SiNH) arrays. When on the hybrid SiNP/SiNH arrays, cells had medium cell areas and they arranged orderly along the boundaries of SiNPs and SiNHs, as well as 80% of cells displayed a preference for SiNPs over SiNHs. Furthermore, the lamellipodia and filopodia are dominant in the hybrid SiNP/SiNH and SiNP arrays, respectively, both of them are dominant in the SiNH arrays. In addition, the atomic force acoustic microscopy was also employed to detect the subsurface features of samples. The results suggest that the hybrid SiNP/SiNH arrays have a targeted trap and elongation effect on cells. The findings provide a promising method in designing hybrid nanostructures for efficient tumor cell traps, as well as regulating the cell behaviors and pseudopodia.