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Sensor Systems for Label-Free Detection of Biomolecular Interactions: Quartz Crystal Microbalance (QCM) and Surface Plasmon Resonance (SPR)
Published in Yallup Kevin, Basiricò Laura, Iniewski Kris, Sensors for Diagnostics and Monitoring, 2018
Şükran Şeker, M. Taner Vurat, Arin Doğan, A. Eser Elçin, Y. Murat Elçin
The other chemical modification method is based on self-assembly with organofunctional chloro- or alkoxysilane molecules on hydroxyl-terminated glass and metal surfaces; this is called silanization. Silanization protocols for quartz crystal with a gold electrode usually include rinsing steps with an acid solution such as piranha solution [34] or chromic acid treatment, which aims to produce high-density hydroxyl groups (-OH) on the surface before silanization [35]. The free hydroxyl groups react with the alkoxy groups on the silane molecules, thus forming a covalent Au-O-Si bond, which is thermodynamically and hydrolytically stable. In the silanization method, the surface is modified by dipping it into a solution containing a silane molecule. This method is very useful for biomolecule immobilization due to the simplicity of the process and the high stability of the modified surface. A number of very different silane derivatives for silanization can be found in the literature. The most commonly used silane molecules in biosensor applications are 3-aminopropyltriethoxysilane (APTES) and 3-aminopropyltrimethoxysilane (APTMS), which generate a self-organizing silane monolayer with terminal amine groups on its surface, using different cross-linkers (e.g., gluteraldehyde) for the further attachment of biomolecules.
Nanocoutured Metallic Biomaterials and Surface Functionalization of Titanium-Based Alloys for Medical Applications
Published in Bhupinder Singh, Rodney J. Y. Ho, Jagat R. Kanwar, NanoBioMaterials, 2018
Jalal Azadmanjiri, Wai Hong Wong, Jagat R. Kanwar, Christopher C. Berndt, James Wang, Vijay K. Srivastava, Ajay Kapoor
Silanization is a low-coat and efficient chemical covalent coating route for addressing a material surface by means of self-assembly with organofunctional alkoxysilane molecules. HA, bioglass, TiO2 and many other metal oxide surfaces can be silanized due to rich hydroxyl groups, which attack and displace the alkoxy groups on the silane, hence, forming a covalent –Si–O–Si– bond. There are numerous kinds of commercially existing silane combining agents which usually are simple to react with hydroxylated surface and present active groups, such as amino groups and carboxyl groups, to the surface (Qiu et al., 2014). Figure 2.11 takes polydimethylsiloxane [PDMS, CH3(Si(CH3)2O)nSi(CH3)3] as an example to demonstrate chemical structure of the surface modification by 3-aminopropyltriethoxysilane (APTES, C9H23NO3Si) with/without glutaraldehyde (GA), adopted by protein immobilization using collagen, and examined the stability of the confluent cell layer and the potency of adhered mesenchymal stem cells (MSCs) for up to three weeks.
Silicon nanocrystals from plasma synthesis
Published in Klaus D. Sattler, Silicon Nanomaterials Sourcebook, 2017
Samantha K. Ehrenberg, Katharine I. Hunter, Uwe R. Kortshagen
Silanization is a technique similar to hydrosilylation that instead acts upon surface hydroxyl groups to attach siloxane groups of silane coupling agents (SCAs) with various functional groups to improve particle solubility. Anderson et al. silanized plasma-synthesized Si nanocrystals ex situ by etching with HNO3 to produce an SiOH surface to which dodecyldimethylchlorosilane ligands were thermally attached. The resulting particles exhibited size-tunable emission with peak wavelengths as low as ~600 nm and low quantum yields, ~2%. The emission was stable upon further air exposure, however, with no further changes measured after 60 days of exposure (Anderson et al. 2012).
Process steam generation from low-grade waste heat in a direct- contact adsorption heat pump based on superhydrophobic surface-modified Zeolite 13X
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Xiaoran He, Ruixun Wei, Ali Jan, Guangyao Li, Tingting Chen, Bing Xue
Conventional alumino-silica zeolites such as 13X, although readily available and low-cost, have the disadvantage of high hydrophilicity and require higher regeneration temperatures to desorb steam from the pores of the materials. Thus, forcing the adsorption system to be coupled to a high temperature heat source. For the sake of energy savings and emission reduction, some studies are devoted to the possibility of modifying zeolite. Silanization is often used to increase the hydrophobicity of inorganic materials (Wang et al. 2021). Bonaccoris (Bonaccorsi et al. 2017b) modified zeolites A, 13X, and Y with four silane coupling agents of different chain lengths to interfere with the diffusion of water molecules into the zeolite pore channels. Minjae Kim (Kim et al. 2022) obtained hydrophobic zeolites with a maximum water contact angle of 129° by modifying zeolite 13X with octadecyltrimethoxysilane containing long chains, and their water resistance was improved by 44%. Therefore, proper hydrophobic modification is a prerequisite for the application of zeolite 13X in a direct-contact adsorption heat pump.