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Ferraris S, Warchomicka F, Barberi J, Cochis A, Scalia AC, Spriano S. Contact Guidance Effect and Prevention of Microfouling on a Beta Titanium Alloy Surface Structured by Electron-Beam Technology. Nanomaterials (Basel) 2021; 11:1474. [PMID: 34199432 DOI: 10.3390/nano11061474] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 05/28/2021] [Accepted: 05/31/2021] [Indexed: 02/06/2023]
Abstract
Nano- and micro-structuring of implantable materials constitute a promising approach to introduce mechanical contact guidance effect, drive cells colonization, as well as to prevent bacteria adhesion and biofilm aggregation, through antifouling topography. Accordingly, this paper aims to extend the application of e-beam surface texturing and nano-structuring to the beta titanium alloys, which are of great interest for biomedical implants because of the low Young modulus and the reduction of the stress shielding effect. The paper shows that surface texturing on the micro-scale (micro-grooves) is functional to a contact guidance effect on gingival fibroblasts. Moreover, nano-structuring, derived from the e-beam surface treatment, is effective to prevent microfouling. In fact, human fibroblasts were cultivated directly onto grooved specimens showing to sense the surface micro-structure thus spreading following the grooves’ orientation. Moreover, Staphylococcus aureus colonies adhesion was prevented by the nano-topographies in comparison to the mirror-polished control, thus demonstrating promising antifouling properties. Furthermore, the research goes into detail to understand the mechanism of microfouling prevention due to nano-topography and microstructure.
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Zhao Y, Zhang G, Nai MH, Ding G, Li D, Liu Y, Hippalgaonkar K, Lim CT, Chi D, Li B, Wu J, Thong JTL. Probing the Physical Origin of Anisotropic Thermal Transport in Black Phosphorus Nanoribbons. Adv Mater 2018; 30:e1804928. [PMID: 30307655 DOI: 10.1002/adma.201804928] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/25/2018] [Indexed: 06/08/2023]
Abstract
Black phosphorus (BP) has emerged as a promising candidate for next-generation electronics and optoelectronics among the 2D family materials due to its extraordinary electrical/optical/optoelectronic properties. Interestingly, BP shows strong anisotropic transport behavior because of its puckered honeycomb structure. Previous studies have demonstrated the thermal transport anisotropy of BP and theoretically attribute this to the anisotropy in both the phonon dispersion relation and the phonon relaxation time. However, the exact origin of such strong anisotropy lacks clarity and has yet to be proven experimentally. Here, the thermal transport anisotropy of BP nanoribbons is probed by an electron beam technique. Direct evidence is provided that the origin of this anisotropy is dominated by the anisotropic phonon group velocity, verified by Young's modulus measurements along different directions. It turns out that the ratio of the thermal conductivity between zigzag (ZZ) and armchair (AC) ribbons is almost same as that of the corresponding Young modulus values. The results from first-principles calculation are consistent with this experimental observation, where the anisotropic phonon group velocity between ZZ and AC is shown. These results provide fundamental insight into the anisotropic thermal transport in low-symmetry crystals.
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Affiliation(s)
- Yunshan Zhao
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Republic of Singapore
| | - Gang Zhang
- Institute of High Performance Computing, Singapore, Singapore, 138632, Republic of Singapore
| | - Mui Hoon Nai
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117576, Republic of Singapore
| | - Guangqian Ding
- School of Science, Chongqing University of Posts and Telecommunications, Chongqing, 400065, China
| | - Dengfeng Li
- School of Science, Chongqing University of Posts and Telecommunications, Chongqing, 400065, China
| | - Yi Liu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Republic of Singapore
| | - Kedar Hippalgaonkar
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, 138634, Republic of Singapore
| | - Chwee Teck Lim
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117576, Republic of Singapore
- Mechanobiology Institute, National University of Singapore, Singapore, 117411, Republic of Singapore
| | - Dongzhi Chi
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, 138634, Republic of Singapore
| | - Baowen Li
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Jing Wu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, 138634, Republic of Singapore
| | - John T L Thong
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Republic of Singapore
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