Carbohydrates sensing

Carbohydrate Sensing by Boronic Acid Derivatives In the pmsuit of sensors for carbohydrates, boronic acids have been utilized for their ability to covalently but... 

Fig. 3 Boronic-acid-based receptors for carbohydrate sensing. (From Refs. [21-25].)...

Cui, Q. W., MuscateUo, M. M., Asher, S. A. (2009). Photonic crystal borax competitive binding carbohydrate sensing motif. Analyst, 134(5), 875-880. 

The macromolecules of cells are built of units—amino acids in proteins, nucleotides in nucleic acids, and carbohydrates in polysaccharides—that have structural polarity. That is, these molecules are not symmetrical, and so they can be thought of as having a head and a tail. Polymerization of these units to form macromolecules occurs by head-to-tail linear connections. Because of this, the polymer also has a head and a tail, and hence, the macromolecule has a sense or direction to its structure (Figure 1.9). 

Somewhat in advance of the widespread usage of the colloidal connotation of Ostwald and others, investigators in a number of instances seem to have favored the view that cellulose, starch, rubber, etc., are polymeric, the term being used in much the same sense as it is used today. The idea that proteins and carbohydrates are polymeric goes back at least to Hlasiwetz and Habermann, who, in 1871, considered... 

PDPH also may be used as a thiolation reagent to add sulfhydryl functional groups to carbohydrate molecules. The reagent can be used in this sense similar to the protocol described for AMBH (Chapter 1, Section 4.1). After modification of an oxidized polysaccharide with the hydrazide end of PDPH, the pyridyl group is removed by treatment with DTT, leaving the exposed sulfhydryl (Figure 5.15). 

This article has not been in any sense an attempt to enumerate all of the known examples of periodate oxidation of carbohydrates. It has endeavored to explain and illustrate as many of the different types of periodate... 

First, the above-mentioned sensors have major drawbacks, as the detection and recognition event is a function of the nature and characteristics of the side chains, and the side chain functionalization of the CP requires advanced synthesis and extensive purification of numerous monomeric and polymeric derivatives. Second, this generation of sensors primarily employed optical absorption as the source for detection, resulting in lower sensitivity when compared with other sensing systems for biological processes. However, the use of fluorescence detection within these sensing systems could justify continued development. More recent examples include a fluorescent polythiophene derivative with carbohydrate functionalized side chains for the detection of different bacteria [15] and novel synthesis schemes for ligand-functionalization of polythiophenes [16]. 

Few chemical sensing mechanisms (other than bulk quenching) have been described for neutral molecules nevertheless, many small analytes of interest are uncharged glucose, for example. Of course, most carbohydrates are neither fluorescent nor are they fluorescence quenchers novel signal transduction mechanisms are required. 

In a certain sense, we live by reversing the process of photosynthesis. Specifically, we bum carbohydrates using oxygen and produce carbon dioxide and water in a process known as respiration ... 

The basic structural unit of carbohydrates is the monosaccharide. Molecules in this class contain just one sugar moiety ahexose, pentose, or whatever. Monosaccharides are the building blocks of more complex carbohydrates in mnch the same sense that amino acids are the building blocks for proteins and nncleotides are the building blocks for nucleic acids. 

His warmth of approach toward new Ph.D. students would put even the most nervous of them at their ease. He loved to engage in day-to-day banter with his research students, as well as discussions of chemistry this arose from his inherent interest in people and life as a whole, and his excellent sense of humor. As a consequence, new students and research assistants quickly settled into their new lab environment, notwithstanding the challenges of the research projects in carbohydrate chemistry they had been set. His excellence of leadership and his ability to rescue students stranded on floundering research projects were all traits that made him a Ph. 

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