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Technologies for Low-Cost, Hall Effect–Based Magnetic Immunosensors
Published in Eric Lagally, Krzysztof Iniewski, Microfluidics and Nanotechnology, 2017
Simone Gambini, Karl Skucha, Jungkyu Kim, Bernhard E. Boser
The first step of an immunoassay is to immobilize the capture antibodies on a substrate. For the standard ELISA, a microplate made out of polystyrene is generally used to attach the capture antibodies by physisorption. However, physisorption does not provide a sufficiently stable binding force on silicon or silicon dioxide surfaces to immobilize the capture antibodies. In this case, the biosensor surface must be functionalized using a linker molecule. The most common functional groups for attaching a capture antibody are reactive amine, epoxy, aldehyde, and carboxylic acid. For the amine functional group, 3-aminopropyl triethoxysilane (APTES) is one of the common linkers that has reactive amine groups. The siloxane groups of APTES react with a hydroxyl group on the silicon-based surface by condensation. Then, a glutaraldehyde as bilinker molecule interconnects between APTES and antibodies [12,13]. When the APTES linker is used, the antibodies can be attached on the surface electrostatically. The APTES-modified surface has positive charges that enable interaction with streptavidin (SA). The biotinylated capture antibodies are then added onto the functionalized surface coated with SA at room temperature [4,14,15]. Another common approach is to use a carbodiimide coupling method that uses 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) chemicals to generate a carboxylic acid functional group on the capture antibodies.
Natural Fiber Reinforced Thermoplastic Composites
Published in Omar Faruk , Jimi Tjong , Mohini Sain, Lightweight and Sustainable Materials for Automotive Applications, 2017
Omar Faruk, Birat KC, Ahmed Sobh, Jimi Tjong, Mohini Sain
In an effort to improve the interfacial interaction between lufa fiber (LF) and PP matrix, Demir et al. [35] investigated the use of three different coupling agents: (1) (3-aminopropyl)-triethoxysilane (AS), (2) 3-(trimethoxysilyl)-1-propanethiol (MS), and (3) MAPP. They discussed the effects of the coupling agents on the mechanical properties in addition to the water sorption characteristics and morphology. They concluded that tensile strength and Young’s modulus increased with coupling agents. Also, water absorption decreased with treatment which was attributed to a better adhesion between fiber and matrix. Optimal mechanical properties were obtained with MS treatment.
Layered Structured Materials and Nanotechnology for Photodetection
Published in Tuan Anh Nguyen, Ram K. Gupta, Nanotechnology for Light Pollution Reduction, 2023
Felipe M. de Souza, Magdalene Asare, Ram K. Gupta
Some of these techniques are silane coupling which consists of the bonding between organic and inorganic moieties over the substrate’s surface by forming hydrogen bonds between the substrate and a silane coupling agent with a structure of X3–Si–(CH2)n–R. Also, gelating coatings can be used which are generally based on the adhesion of (3-aminopropyl)-triethoxysilane which is dried over the substrate and promotes hydrogen bonding with it along with exposed amino groups that can be later used for functionalization with active material. The recording media consists of a photosensitive material that can capture and store information from the radiation. An example of that is AgX where X are halides that can be incorporated into a polymeric matrix that is coated over a substrate. Some of the polymers available for that are poly(vinyl alcohol) (PVA), poly(2-hydroxy methacrylate), and poly(acrylamide). Nanoparticles can also be added to enhance the detection and recording properties of the sensor. Yet, the nanoparticles must be stable over the polymer matrix, show good affinity toward the analyte, proper refractive index, and size. For the case of the latter, nanoparticle sizes within the range of 10–30 nm can be used to diminish light scattering, which is directly related to a higher diffraction efficiency and higher contrast. In addition, nanoparticles that present a refractive index that differs from the recording material can be used to create a larger dynamic range enabling it to record multiple holograms. Through that, these holographic sensors can be used for a myriad of detection systems. A summary of some of the analytes that these photoactive sensors can identify is provided in Table 16.1 [5].
A Multi-Step model to predict the size of stabilized oil droplets in pickering emulsions containing janus and non-janus nanoparticles
Published in Journal of Dispersion Science and Technology, 2023
Esmail Sharifzadeh, Fiona Ader
(3-Aminopropyl) triethoxysilane (APTES, Aldrich, 99%) is used as the surface modification agent in homogenously and asymmetrically surface modification processes. OX-50 silica nanoparticles (d = 40 nm, Tapped density130 g L−1, bulk density2.2 g.cm−1, Degussa, France) are used as the base for synthesizing HM and Janus nanoparticles. Paraffin (Dr. Mojallali Co., melting point: 56–58 °C, density 0.9 g.cm−3) is used as the oil phase to produce different Pickering emulsion samples and also as the substrate in the desymmetrization process to produce silica Janus nanoparticles. Chloroform (Dr. Mojallali Co., >98%) is applied to dissolve the paraffin substrates, in the desymmetrization process, and ethanol (Merck, >99%) is used as the media in the different surface modification processes.
Which is better? Experimental and simulation analyses of the chemical modification of carbon nanotubes to improve their dispersion in water
Published in Journal of Dispersion Science and Technology, 2021
I. Montes-Zavala, E. O. Castrejón-González, V. Rico-Ramírez, Elias Pérez, Diego A. Santamaría-Razo, J. A. González-Calderón
A chemical modification that has been used to improve nanomaterials dispersion involves the use of silans. (3-Aminopropyl) triethoxysilane (3-APTES) as coupling agent due to the amino groups that it contains; in particular, an ethoxy group that lodges on the sides of the molecule can form a covalent bond with other surfaces. Recent studies on nanostructure doping with 3-APTES show that ethoxy and amino groups are chemically linked on active surfaces of silicon dioxide nanoparticles and on oxidized surfaces of carbon nanotubes. This modification increases the resistance to bending due to the dispersion in the nanocomposite.[18] It was further observed that chemical functionalization in an aqueous environment is possible; such study resulted in an important industrial application and a positive effect on the hardness of the material.[19] Another study revealed the relationship between silane concentration, surface coverage and functionalization of carbon nanotubes. It was found that the optimal range of silane concentration is between 1 and 2 times the weight of the carbon nanotubes, which remain suspended in a liquid vinyl ester resin.[20] New methods for chemical functionalization with silans involve the use of 3-APTES vapor to produce an aminated layer on the surface of Muti-Walled Carbon NanoTubes (MWCNT), which can be dispersed in water or ethanol; however, when dispersed in water, they present unstable behavior. That is possibly due to the reaction of 3-APTES with the forming insoluble oligomers.[21]
Solution based freeze cast polymer derived ceramics for isothermal wicking - relationship between pore structure and imbibition
Published in Science and Technology of Advanced Materials, 2019
Daniel Schumacher, Dawid Zimnik, Michaela Wilhelm, Michael Dreyer, Kurosch Rezwan
Methylpolysiloxane and (3-aminopropyl)triethoxysilane were used as a precursor and cross-linking agent, respectively. Tert-butyl alcohol or cyclohexane was used as solvents to obtain a prismatic or dendritic pore morphology. Differences in solid loading and the addition of preceramic filler particles change the porosity from 60% to 79% and the mean pore window diameter from 11 μm to 21 μm. A silicon-coated film prevents nucleation on the lateral surface, resulting in a dense lateral surface. The samples with such a dense layer showed 2.3 to 5.9 times lower water flux of the lateral surface compared with an open surface.