China
Africa
Explore chapters and articles related to this topic
Facile Chemical Fabrication of Designer Biofunctionalized Nanomaterials
Published in Vineet Kumar, Praveen Guleria, Nandita Dasgupta, Shivendu Ranjan, Functionalized Nanomaterials I, 2020
Biotinylation of nanoparticles with avidin is very commonly found in biological application. This is due to the fairly high affinity of avidin–biotin interactions, which is around 1014. The surfaces of nanoparticles can be biofunctionalized with avidin molecules which specifically bind to four molecules of biotin. For example, avidin-functionalized Ce/Tb-doped LaPO4 nanoparticles are used for the assembly of biotinylated proteins, which makes them an ideal crosslinker (Kim et al., 2008). Biotin–avidin interaction is explained elaborately in the following section. The conjugation of biotinylated polyethylene glycol or phospholipids to the surfaces of nanoparticles can interact with avidin or avidin-functionalized species, making them applicable as good biosensing agents.
Nanoparticles Carrying Biological Molecules
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Suryani Saallah, Wuled Lenggoro
Generally, physical conjugation offers a simple and rapid route to bind biomolecule to the NP and requires minimal modification steps (Saallah and Lenggoro, 2018). Thus, the biomolecules’ functionalities can be preserved. Nevertheless, this method suffers from weak binding, random orientation, high likelihood of desorption, and poor reproducibility (Liebana and Drago, 2016). Such drawbacks can be overcome by introducing specific functional groups or targeting ligands to the nanoparticles through affinity interactions. The most well-known example in the last several decades is the avidin–biotin system. Avidin comprises four identical subunits that provide four binding pockets which specifically recognize and bind to biotin, resulting in a strong and stable interaction with a dissociation constant, KD, of the order of 10–15 M. The combination of basic pI and carbohydrate content, however, results in nonspecific binding as observed in several applications (Sapsford et al., 2013). Alternatively, streptavidin, a non-glycosylated homologous tetrameric protein displaying similar affinity to biotin, can be used as avidin analog (Saallah and Lenggoro, 2018). The mechanism of the most widely applied non-covalent interactions is illustrated in Figure 4.7.
Protocols for Key Steps in the Development of an Immunoassay
Published in Richard O’Kennedy, Caroline Murphy, Immunoassays, 2017
Caroline Murphy, Richard O’Kennedy
The biotin/avidin interaction is used in a wide variety of applications from affinity chromatography to signal detection. Thermo Scientific have a wide range of biotinylation reagents to suit different applications, with varying lengths to reduce steric hindrance effects. The most commonly used reactive biotinylation products are N-hydroxy-succinimide (NHS)-biotin and sulfo-NHS-biotin. Both are ester molecules which interact with N-terminal amines or amines found in lysines. Thermo Scientific’s sulfo-NHS-long-chain (LC)-biotin molecule is most commonly used for antibody conjugation as it is the most simplest and is usually most effective. Alternative methods of antibody-biotinylation include the use of NHS-PEG4- biotin which is also amine reactive and increases solubility of the biotinylated molecule. Finally, biotin-PEG4-hydrazine from Thermo Scientific reacts with carbohydrate and is commonly used for the conjugation of biotin molecules to polyclonal antibodies. Protocols 12.8 and 12.9 outline the biotinylation of antibodies and their subsequent capture onto streptavidin-coated QDs.
Electrochemical sensing by a covalently bonded biotin–avidin couple on a silver nanoparticle modified gold electrode
Published in Instrumentation Science & Technology, 2021
Of these devices, the biotin–avidin couple is extensively used in a variety of technological applications such as clinical diagnosis, drug targeting, immunolabelling, bioengineering and biomedicine, biomolecular purification, and separations. Therefore, an electrochemical sensing platform to quantify the biotin–avidin interaction has attracted attention for the applications in related biological analysis.[3–5] For these electrochemical biosensors, the key step is successful immobilization of biomolecules on the solid electrode to provide significant electron movement during electrochemical characterization commonly performed by voltammetric and impedimetric measurements.[6–10]