Biomolecules extraction

Fatty alcohol- (or alkyl-)ethoxylates, CoE, are considered to be better candidates for LLE based on their ability to induce rapid phase separation for Winsor II and III systems. (Winsor III systems consist of excess aqueous and organic phases, and a middle phase containing bicontinuous microemulsions.) However, C,E,-type surfactants alone cannot extract biomolecules, presumably because they have no net negative charge, in contrast to sorbitan esters [24,26,30,31]. But, when combined with an additional anionic surfactant such as AOT or sodium benzene dodecyl sulfonate (SDBS), or affinity surfactant, extraction readily occurs [30,31]. The second surfactant must be present beyond a minimum threshold value so that its interfacial concentration is sufficiently large to be seen by... 

Solid phase extraction systems containing surfaces with dicarboxylic acid termini, (II), were prepared by Bakry [3] and used to extract biomolecules such as viruses, proteins, antigens, and RNA and DNA complexes. A similar extraction system was prepared by Gierde [4] using polyglutarmic acid. 

Proteinaceous extracts from diatoms, sponges, and higher plants have been used in model studies of silicification in order to identify the role of the extracted biomolecules. 

TABLE 1 Surfactant Systems Employed for w/o-ME-Based Liquid-Liquid Extraction (LEE) of Biomolecules... 

Depicted in Fig. 2, microemulsion-based liquid liquid extraction (LLE) of biomolecules consists of the contacting of a biomolecule-containing aqueous solution with a surfactant-containing lipophilic phase. Upon contact, some of the water and biomolecules will transfer to the organic phase, depending on the phase equilibrium position, resulting in a biphasic Winsor II system (w/o-ME phase in equilibrium with an excess aqueous phase). Besides serving as a means to solubilize biomolecules in w/o-MEs, LLE has been frequently used to isolate and separate amino acids, peptides and proteins [4, and references therein]. In addition, LLE has recently been employed to isolate vitamins, antibiotics, and nucleotides [6,19,40,77-79]. Industrially relevant applications of LLE are listed in Table 2 [14,15,20,80-90]. 

An alternate approach for biomolecule recover is to employ degradable surfactants [157]. A series of nonionic surfactants has been synthesized that contain the acidic pH-degradable cyclic ketal linkage [153]. These surfactants readily form w/o-MEs when at neutral pH or higher but, the surfactants readily degrade at moderately low pH (ca. 5), releasing the encapsulated aqueous phase and its constituents. Work is ongoing to develop these surfactants in w/o-ME protein extraction processes [153]. 

Recent reports describe the use of various porous carbon materials for protein adsorption. For example, Hyeon and coworkers summarized the recent development of porous carbon materials in their review [163], where the successful use of mesoporous carbons as adsorbents for bulky pollutants, as electrodes for supercapacitors and fuel cells, and as hosts for protein immobilization are described. Gogotsi and coworkers synthesized novel mesoporous carbon materials using ternary MAX-phase carbides that can be optimized for efficient adsorption of large inflammatory proteins [164]. The synthesized carbons possess tunable pore size with a large volume of slit-shaped mesopores. They demonstrated that not only micropores (0.4—2 nm) but also mesopores (2-50 nm) can be tuned in a controlled way by extraction of metals from carbides, providing a mechanism for the optimization of adsorption systems for selective adsorption of a large variety of biomolecules. Furthermore, Vinu and coworkers have successfully developed the synthesis of... 

Adsorption of small biomolecules such as amino acids, vitamins, and oligopeptides on mesoporous materials is also an important research target, because it certainly satisfies certain demands in material extraction, drug delivery, and pollutant removal. Vinu and coworkers recently reported systematic research on the adsorption of L-histidine on mesoporous materials [187,188]. Figure 4.22 compares the adsorption... 

We conducted proteomic analysis of the KO mouse brain to identify proteins or peptides whose expression levels may change due to a lack of SCRAPPER. Imaging MS allowed us to statistically analyze location and expression intensities of many biomolecules and to extract molecules that exhibited region-specific expression. Groups of molecules whose expression patterns differed between WT mice and KO mice particularly attracted our attention. 

FIGURE 58-2 Hydrogen ( H) spectrum from a normal human brain at 4 Tesla field strength. The spectrum is very complicated, comprised of many overlapping peaks which are difficult to resolve from each other. Spectral analysis routines make use of spectral models which are constructed from the individual spectra acquired from each biomolecule from in vitro solutions. This model is then fitted to the raw data and approximate concentrations for each biomolecule are extracted... 

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