Adsorption of biomolecules

These excellent textural characteristics would be very useful for the adsorption of biomolecules. Figure 4.17 compares the adsorption behavior of lysozyme on CMK-3 (plot (a)), CMK-3-150 (plot (b)), and the carbon nanocage (plot (c)) at pH 11 [154],... 

The developed prototype includes a source of ultraviolet (UV) radiation (1) with the wavelength of 350 nm, two photodiodes (2 and 3) based on a silicon monocrystal and placed at the angle of 20-25° relative to the plate with sNPS layer (4) and a photodiode (5) for detection of the incident UV light (Fig. 9.6). Upon adsorption of biomolecules the level of the sNPS photoluminescence and the output of the voltage of the consecutively connected photo detectors decrease. Use of two photodetectors of photoluminescence increases the biosensor sensitivity. 

Simplification is necessary for understanding most real processes. In this case the description begins with material on the adsorption of biomolecules on metals then we discuss the active field that has developed in a study of electron transfer from modified metal electrodes to proteins dissolved in solution finally we describe the as-yet less well developed study of charge transfer from proteins to simple redox ions in solution. The real field of course is the kinetics and mechanism of electron transfer from proteins to biomolecules, but this area of experimental research is as yet a bridge too far. 

Of the dozen or so methods that have been used to examine the adsorption of biomolecules onto metals from solution, those most suited seem to be (1) cyclic voltrammetry, (2) ellipsometry, (3) Fourier transform infrared spectroscopy, and (4) atomic force microscopy. 

There is still another disadvantage normally associated with the use of ATR-techniques for biological samples in the visible. That is the strong adsorption of biomolecules on the surface of the reflection element this causes adsorption contamination between two successive samples. This problem, however, could be solved (patents pending) by using disposable slides of the same material in optical contact with the reflection element or by using a liquid interface, as shown in Figure 6. For example,... 

Voute, N., Bataille, D., Girot, P., and Boschetti, E. (1999). Characterization of very dense mineral oxides-gel composites for fluidized bed adsorption of biomolecules. Bioseparation 8, 121-129. 

The enhanced fluorescence detection capability of ZnO NR platforms is further assessed in relatively simple biological assays involving pure DNA and proteins. Unlike the previously described tests involving single layer adsorption of biomolecules, biological assays discussed from here on pertain to interactions between multilayered biomolecules. The following sections describe the results of fluorescence enhancement effect observed in these relatively simple but multilayered bioassays on ZnO NRs. 

Before dealing with the adsorption of biomolecules (proteins and nucleic acids) onto latex particles, we should recall certain aspects (which will not be defined here) of the adsorption of macromolecules on solid-liquid interfaces. Biomolecules are complex macromolecules in nature, which in... 

The adsorption of biomolecules onto carriers that are insoluble in water is the simplest method of immobilization. An aqueous solution of the biomolecules is contacted with the active carrier material for a defined period of time. Thereafter the molecules that are not adsorbed are removed by washing. Anionic and cationic ion exchange resins, active charcoal, silica gel, clay, aluminum oxide, porous glass, and ceramics are being currently used as active material. The carrier should exhibit high affinity and capacity for the biomolecule and the latter must remain active in the adsorbed state. The carrier should adsorb neither reaction products nor inhibitors of the biocatalyst. 

The reactions of biopolymers at interfaces form the basis of some extremely important industrial processes. The primary process in all cases is the adsorption of biomolecules, usually proteins. If ultimately living cells are adsorbed, this always takes place onto a preadsorbed protein layer (which may be secreted by the cells themselves [130])- These processes can be classified into three categories ... 

Fig. 14.44 Illustration of the shift in resonance angle at various stages in the adsorption of biomolecules to the metal surface.

Polypropylene, polyethylene, and its copolymers, including polyvinyl alcohol-co-ethylene (EVAL) and polyethylene-co-maleic anhydride, are often reported in the literature as affinity supports for different ligand chemistries (Figure 6.5). Bare polyethylene and polypropylene membranes have good thermal, mechanical, and chemical resistance but are inert and show a too high nonspecific adsorption of biomolecules. Therefore, an additional surface modification step... 

Since oligoethylene glycol is known to prevent the adsorption of biomolecules such as proteins, a triethylene glycol-like compound was employed as the linker to incorporate into the ligands A, B, and C. The preparation of the linker using standard Fmoc chemistry on solid support is illustrated in Figure 14.5. 

In the design of medical implants and materials, control of the adsorption of biomolecules such as proteins and related compounds is crucial in order to achieve a fast assimilation process i.e. absorption by the body). Different... 

Biomolecular adsorption in microfluidics usually refers to the nonspecific adsorption of biomolecules (amino acids, peptides, DNA, RNA, proteins, and cells) onto the surfaces of microfluidic devices. In this sense, this is often referred as... 

Rimola, A., D. Costa, M. Sodupe, J.-F. Lambert, and P. Ughengo, Silica surface features and their role in the adsorption of biomolecules Computational modeling and experiments. Chemical Reviews, 2013. 113, 4216-4313. 

Adsorption of biomolecules at the electrode surface is the simplest method of immobilization. An aqueous solution of the biomolecules is contacted with the active surface for defined period. Thereafter the molecules that are not adsorbed are removed by washing. 

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