Efficient Excitation of Channel Plasmons in Tailored, UV-Lithography-Defined V-Grooves

Bae

Adv Healthcare Materials

et al. 2017

Topographic features play a crucial role in the regulation of physiologically relevant cell and tissue functions. Here, an analysis of feature-size-dependent cell-nanoarchitecture interactions is reported using an array of scaffolds in the form of uniformly spaced ridge/groove structures for engineering wound healing. The ridge and groove widths of nanopatterns are varied from 300 to 800 nm and the nanotopography features are classified into three size ranges: dense (300-400 nm), intermediate (500-600 nm), and sparse (700-800 nm). On these matrices, fibroblasts demonstrate a biphasic trend of cell body and nucleus elongation showing the maximum at intermediate feature density, whereas maximum migration speed is observed at the dense case with monotonic decrease upon increasing feature size. The directional organization of cell-synthesized fibronectin fibers can be regulated differently via the nanotopographical features. In an in vitro wound healing model, the covering rate of cell-free regions is maximized on the dense nanotopography and decreased with increasing feature size, showing direct correlation with the trend of migration speed. It is demonstrated that the properties of repaired tissue matrices in the process of wound healing may be controlled via the feature-size-dependent cell-nanoarchitecture interactions, which can be an important consideration for designing tissue engineering scaffolds.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Directional Matrix Nanotopography with Varied Sizes for Engineering Wound Healing

Bae

Adv Healthcare Materials

et al. 2017

“…The SPP propagation losses are estimated by comparing the fluorescence spectrum emitted at the source and the spectrum of the light dispersed by a scatterer. The main idea behind such an experiment is to obtain a classical characterization of the NV-SPP coupling, scattering and associated losses, in order to validate their use for more complex plasmonic devices, such as in dielectric-loaded waveguides [13], Vgrooves [14], nano-antennas [15], etc.The NDs used in this work consist of two nanocrystals with diameters around 100 nm and each ND containing …”

mentioning

confidence: 99%

Local excitation of surface plasmon polaritons using nitrogen-vacancy centers

2015

Self Cite

Surface plasmon polaritons (SPPs) are locally excited at silver surfaces using (~100) nm-sized nanodiamonds (NDs) with multiple nitrogen-vacancy (NV) centers (~400). The fluorescence from an externally illuminated (at 532 nm) ND and from nearby NDs, which are not illuminated but produce out-of-plane scattering of SPPs excited by the illuminated ND, exhibit distinctly different wavelength spectra, showing short-wavelength filtering due to the SPP propagation loss. The results indicate that NDs with multiple NV centers can be used as efficient sub-wavelength SPP sources in planar integrated plasmonics for various applications.Nitrogen-vacancy (NV) centers in diamond are defects in the crystal structure consisting of a nitrogen atom and a lattice vacancy oriented along the [111] direction [1]. NV centers are of interest because they behave as artificial atoms and can be used as single photon sources [2]. Photostability is another important characteristic of NV centers [3]. In addition, NV centers can be created in desired locations in bulk or deterministically moved and positioned in nanodiamonds [4,5]. In spintronics, these color centers offer the possibility to measure the electronic spin optically at room temperatures [6], thus facilitating the research in quantum information processing [7]. Although many of the interesting characteristics of NV centers are interesting for single NV centers, the study and application of diamond nanoparticles with multiple NV centers is also significant. Nanodiamonds (NDs) with multiple NV centers can be used to measure magnetic fields with higher precision, and with plasmonic devices it can be improved further [8]. Surface plasmon polaritons (SPPs) manifest as evanescent electromagnetic fields at the interface between a metal and a dielectric and can be confined well below the diffraction limit, thus the use of a sub-wavelength, tightly localized optical source to excite SPPs is a natural need [9].In recent work, NDs with NV centers have been used as single photon sources to couple propagating SPPs in silver nanowires where a reduction of lifetime [5,10], and the wave-particle duality were observed [11]. Additionally, the leakage radiation of SPPs excited with fluorescence from a ND, mounted on a scanning near-field microscopy (SNOM) tip, was measured to show the preservation of coherence through the first and second order correlation experiments [12]. Even though the latter reference deals with more than one NV center (~5), the research is still in the frontier between classical and quantum optics. As commented before, most of the research related to SPPs and NV centers point towards quantum properties and have left the classical approximation unattended.In this Letter, we address the local excitation of SPPs with sub-wavelength optical sources using a single ND with multiple NV centers. The SPP propagation losses are estimated by comparing the fluorescence spectrum emitted at the source and the spectrum of the light dispersed by a scatterer. The main idea behind such an experi...

“…It is thus necessary to develop a fundamental understanding on the mechanistic processes induced by anisotropic structures in cell biology, in order to gain further insights into the design of biological materials. Novel techniques of nanofabrication and material processing, such as lithographic (Diehl et al, 2005;Zhu et al, 2005;Dalby et al, 2006;Smith et al, 2014) self-assembly (Tsai et al, 2014), electrospinning (Gaharwar et al, 2014), and scratching techniques (Peng et al, 2010;Wang et al, 2013a), offer the ability to create anisotropic substrates with feature widths and depths ranging from the macroscale to the microscale down to features sizes as small as 5 nm, facilitating the aquisition of information to help understand this field (Peng et al, 2010;Wang et al, 2013a) (Figure 1). These techniques are particularly suited for the generation of anisotropic micro-nanofeatures in polymeric formulations and in particular in thermoplastics.…”

Section: Anisotropic Topography and Cellular Function Anisotropic Biomentioning

confidence: 99%

Sensing the Difference: The Influence of Anisotropic Cues on Cell Behavior

et al. 2015

From tissue morphogenesis to homeostasis, cells continuously experience and respond to physical, chemical, and biological cues commonly presented in gradients. In this article, we focus our discussion on the importance of nano/micro topographic cues on cell activity, and the role of anisotropic milieus play on cell behavior, mostly adhesion and migration. We present the need to study physiological gradients in vitro. To do this, we review different cell migration mechanisms and how adherent cells react to the presence of complex tissue-like environments and cell-surface stimulation in 2D and 3D (e.g., ventral/dorsal anisotropy).