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Nanotopography
Published in Ungyu Paik, Jea-Gun Park, Nanoparticle Engineering for Chemical-Mechanical Planarization, 2019
Nanotopography is measured by two techniques: light scattering and interferometry. Light scattering tools typically employed for particle and surface-defect characterization can be used to measure the local slope change over the entire surface of the wafer. The local slope change may be integrated to yield height or topography information. Since the beam size can be on the order of fractions of a micron, nanotopography can be measured. Optical interference measurement is straightforward: A beam is split into two components—one component is reflected from the wafer surface and the second is reflected from a reference mirror. The interference of the combination of the two beams is a measurement of the topology of the wafer surface. With both techniques, signal filtering is used to separate the low-wavelength features (i.e., warp) so that only the high-wavelength/low-frequency information, (i.e., the true surface nanotopography) is measured. The equipment used in measuring the nanotopography of the wafer will be introduced in Section 5.4.
Nanotemplated Materials for Advanced Drug Delivery Systems
Published in Sanjay V. Malhotra, B. L. V. Prasad, Jordi Fraxedas, Molecular Materials, 2017
Erica Schlesinger, Daniel A. Bernards, Rachel Gamson, Tejal A. Desai
In addition to applications in drug delivery, nanotopography is also being integrated in drug delivery devices, implants, and tissue engineering scaffolds to improve long-term biocompatibility. Implanting a foreign object into the body commonly elicits an immune or fibrotic response. Implantation damage to the surrounding tissue can trigger fibrosis even for biocompatible materials, which may ultimately lead to fibrotic encapsulation. This response is not only harmful, resulting in irreversible damage and scar tissue, but fibrous encapsulation may impact release rates and device function for drug delivery systems. Surface modifications and coatings are a common approach to reduce fibrosis in medical implants and drug delivery devices. While not fully understood, several groups have recently observed that micro- and nanotopography can reduce fibroblast proliferation and fibrotic response (Baker, 2012; Kam, 2014; Smith et al., 2011). As discussed, nanotopographical features are on a size scale that allows interaction with individual cells as well as functional proteins. Nanotopography is hypothesized to affect adsorption and distribution of extra-cellular matrix proteins on implant surfaces and to interact directly with fibroblasts: this reduces proliferation and gene expression of key components of the fibrotic response (Kam, 2014).
Micro- and Nanotechnology in Tissue Engineering
Published in Yubing Xie, The Nanobiotechnology Handbook, 2012
Jane Wang, Robert Langer, Jeffrey T. Borenstein
As mentioned earlier, nanoscale features provide mechanotransductive cues to cells, and influence them in many ways. One of the most prominent cell responses toward nanotopographic features are morphologic changes on cells, especially fibroblasts, endothelial cells, epithelial cells, stem cells, and Schwann cells (Hsu et al. 2005). Cell morphology responds to nanogratings by simultaneously aligning and elongating along the direction of the grating as shown in Figure 22.3 (Teixeira et al. 2006). In addition to modifying cell geometry, nanotopography affects cell proliferation and migration in various cell types. Nanoscale features slow down the proliferation rate, but increase migration velocities (Bettinger et al. 2009b). More recent work showed that nanotopography also enhances cell attachment and adhesion (Mahdavi et al. 2008).
Hydroxyapatite incorporated bacterial cellulose hydrogels as a cost-effective 3D cell culture platform
Published in Soft Materials, 2022
Sandya Shiranthi Athukorala, Chathudina J. Liyanage, Anil C. A. Jayasundera
Surface structure of BC platforms can be greatly affected by the morphology and structure of impregnated HA. Previous studies have shown that the surface nanotopography is a critical feature for the tissue acceptance and cell survival, which can lead to an enhanced cellular function.[30] AFM images of test samples are shown in Figure 2 and the purpose of images in Figure 2 is only to show the 3D topography of hydrogel composites and therefore they do not have identical sizes. Statistical data were software generated from AFM line profiles and they are represented in Table 1.