**1. Introduction**

[48] Seto H, Ogata Y, Murakami T, Hoshino Y, Miura Y., Selective protein separation us‐ ing siliceous materials with a trimethoxysilane-containing glycopolymer. ACS Appl.

An Integrated View of the Molecular Recognition and Toxinology - From Analytical Procedures to Biomedical

[49] Li X, Wu P, Gao G F, Cheng S., Carbohydrate-functionalized chitosan fiber for influ‐

[50] Nagatsuka T, Uzawa H, Ohsawa I, Seto Y, Nishida Y., Use of lactose against the deadly biological toxin Ricin. ACS Appl Mater. Interfaces. 2010; 2(4): 1081-1085. [51] El-Boubbou K, Gruden C, Huang X., Magnetic glycol-nanoparticles: a unique tool of rapid pathogen detection, decontamination, and strain differentiation. J. Am. Chem.

[52] Kitov P I, Sadowska J M, Mulvey G, Armstrong G D, Ling H, Pannu N S, Read R J, Bundle D R., Shiga-like toxin are neutralized by tailored multivalent carbohydrate li‐

[53] Wolfenden M L, Cloninger M J., Mannose/glucose-functionalizied dendrimers to in‐ vestigate the predictable tenability of multivalent interactions. J. Am. Chem. Soc.

[54] Carbre Y M, Roy R., Design and creativity in synthesis of multivalent neoglycoconju‐

[55] Fukuda T, Onogi S, Miura Y., Dendritic sugar-microarrays by click chemistry. Thin

[56] Fukuda T, Matsumoto E, Onogi S, Miura Y., Aggregation of Alzheimer amyloid β peptide (1-42) on the multivalent sulfonated sugar interface. Bioconjugate Chem.

[57] Suda Y, Arano A, Fukui Y, Koshida S, Wakao M, Nishimura T, Kusumoto S, Sobel M., Immobilization and clustering of structurally defined oligosaccharides for sugar chips: an improved method for surface plasmon resonance analysis of protein-carbo‐

gates. Adv. Carbohydr. Chem. Biochem. 2010; 63(10), 165-393.

hydrate interactions. Bioconjugate Chem. 2006; 17(5): 1125-1135.

enza virus capture. Biomacromolecules.2011;12(11): 3962-3969.

Mater. Interfaces. 2012; 4(1), 411-417.

Applications

470

Soc. 2007; 129(44): 13392-13393.

gands. Nature. 2000; 403: 669-672.

Solid Films. 2009; 518(2): 880-888.

2005; 127(35): 12168-12169.

2010; 21(6):1079-1086.

### **1.1. Cyclodextrins**

A cyclodextrin (CyD) is a cyclic oligomer of α-D-glucose formed by the action of certain enzymes, Bacillus amylobacter, on starch. The first reported reference to a cyclodextrin was published by Villiers in 1891 [1]. Three cyclodextrins are readily available: α-CyD, β-CyD and γ-CyD having six, seven and eight glucose units respectively. They are com‐ monly referred to as the native CyDs. For a long time, only the three parent CyDs were known, but during the past decade many covalently modified CyDs have been prepared from the native forms [2].

The glucose units are connected through glycosidic α-1,4 bonds. As a consequence of the 4 C1 conformation of the glucopyranose units, all secondary hydroxyl groups are situated on one of the two edges of the ring, whereas all the primary ones are placed on the other edge. The ring, in reality, is a conical cylinder, which is frequently characterized as a doughnut or wreathshaped truncated cone. It is, of course, the possession of this cavity that makes the CyDs attractive subjects for study. The most notable feature of cyclodextrins is their ability to form inclusion complexes (host–guest complexes) with a very wide range of solid, liquid and gaseous compounds. Complex formation is a dimensional fit between host cavity and guest molecule [3]. This phenomenon bears the name molecular recognition [4].

### **1.2. Inclusion complex formation**

The lipophilic cavity of cyclodextrin molecules provides a microenvironment into which appropriately sized non-polar moieties can enter to form inclusion complexes [5]. No covalent bonds are broken or formed during formation of the inclusion complex [6]. The first driving force of complex formation is release of enthalpy-rich water molecules from the cavity. The second critical factor is the thermodynamic interactions between the different components of

the system (cyclodextrin, guest, solvent). The cavity size of the toroidally shaped CyDs and the structural confrmation and size of the guest molecule are the other parameters that mostly affect the formation of a guest-CyD complex [2]. As the results of this inclusion, changes of the chemical or physical properties of both host and guest molecules are generally observed; opening a wide field of applications in many areas and allowing one to monitor the process by several experimental techniques [2,7-9].

Some of the spectroscopic techniques such as UV-Visible, fluorescence, and NMR spectroscopy are compatible for the spectral study of the complexes that obtained in solution [11]. But the infrared spectroscopy, X-ray diffraction, scanning electron microscopy techniques [12,13] and differential scanning calorimetry [14], are suitable for the inclusion compounds that obtained

Cyclodextrin Based Spectral Changes http://dx.doi.org/10.5772/52824 473

**Figure 2.** NMR spectra of the trans-1,4-bis[(4-pyridyl)ethenyl]benzene ( BPEB) bridged ligand as function of time for the self-assembling {[Fe(CN5)]2(BPEB.β-CyD)}6– rotaxane, upon addition of 2 equivalents of β-CyD to the dimer in D2O:

(a) 0 min, (b) 5 min, (c) 30 min, (d) 60 min and (e) 24 hours.

in the solid state.

**Figure 1.** Structure of α-CyD, β-CyD and γ-CyD
