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ZnO Tetrapods for Label-Free Optical Biosensing: Physicochemical Characterization and Functionalization Strategies. Int J Mol Sci 2023; 24:ijms24054449. [PMID: 36901879 PMCID: PMC10002590 DOI: 10.3390/ijms24054449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/14/2023] [Accepted: 02/20/2023] [Indexed: 02/26/2023] Open
Abstract
In this study, we fabricated three different ZnO tetrapodal nanostructures (ZnO-Ts) by a combustion process and studied their physicochemical properties by different techniques to evaluate their potentiality for label-free biosensing purposes. Then, we explored the chemical reactivity of ZnO-Ts by quantifying the available functional hydroxyl groups (-OH) on the transducer surface necessary for biosensor development. The best ZnO-T sample was chemically modified and bioconjugated with biotin as a model bioprobe by a multi-step procedure based on silanization and carbodiimide chemistry. The results demonstrated that the ZnO-Ts could be easily and efficiently biomodified, and sensing experiments based on the streptavidin target detection confirmed these structures' suitability for biosensing applications.
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Knoepfel A, Liu N, Hou Y, Sujani S, dos Reis BR, White R, Wang K, Poudel B, Gupta S, Priya S. Development of Tetrapod Zinc Oxide-Based UV Sensor for Precision Livestock Farming and Productivity. BIOSENSORS 2022; 12:837. [PMID: 36290974 PMCID: PMC9599082 DOI: 10.3390/bios12100837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/01/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
In order to ensure the health and welfare of livestock, there has been an emphasis on precision farming of ruminant animals. Monitoring the life index of ruminant animals is of importance for intelligent farming. Here, a wearable sensor for monitoring ultraviolet (UV) radiation is demonstrated to understand the effect of primary and secondary photosensitization on dairy animals. Thin films of wide bandgap semiconductor zinc oxide (ZnO) comprising multilevel of nanostructures from microparticles (MP) to nanoparticles (NP), and tetrapod (T-ZnO), were prepared as the UV sensing active materials. The sensitivity was evaluated by exposing the films to various radiation sources, i.e., 365 nm (UV A), 302 nm (UV B), and 254 nm (UV C), and measuring the electrical resistance change. T-ZnO is found to exhibit higher sensitivity and stable response (on/off) upon exposure to UV A and UV B radiation, which is attributed to their higher surface area, aspect ratio, porosity, and interconnective networks inducing a high density of chemical interaction sites and consequently improved photocurrent generation. A wearable sensor using T-ZnO is packaged and attached to a collar for dynamic monitoring of UV response on ruminant animals (e.g., sheep in this study). The excellent performance of T-ZnO wearable sensors for ruminant animals also holds the potential for a wider range of applications such as residential buildings and public spaces.
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Affiliation(s)
- Abbey Knoepfel
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Na Liu
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Yuchen Hou
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Sathya Sujani
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Barbara Roqueto dos Reis
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Robin White
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Kai Wang
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Bed Poudel
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Sanju Gupta
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Shashank Priya
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA
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