Cyclodextrins, dendrimer polymers

Generally speaking, an antenna for light harvesting is an organized multicomponent system in which several chro-mophoric molecular species absorb the incident light and channel the excitation energy to a common acceptor component. Artificial antenna systems based on porphyrin arrays [63], multichromophoric cyclodextrins [64], polynuclear metal complexes [65, 66], dendrimers [66-68], and polymers [69, 70] have been reported. In all these systems, the chromophoric units are connected by means of covalent... 

Polyplexes are formed from many cationic polymers such as histones, PEI, dendrimers (pDMAEM) or carbohydrate-based polymers such as chitosan and cyclodextrin. Polyplexes are smaller in size than lipoplexes, which is a major physicochemical property for gene delivery, especially in vivoJ... 

The use of bilayer coatings was reported from Kapnissi et al. [31], where a permanently adsorbed coating of a cationic polymer salt [poly(diaIlymethylammo-nium chloride)] was covered with a dynamically adsorbed polymeric surfactant [poly (sodium undecylenic sulfate)]. In contrast to the stable coatings, the adsorbed layers can be easily prepared. Traditionally, polymeric surfactants have been used in MEKC [38] and the separation principle can therefore be transferred to o-CEC. However, several other types of dynamically attached pseudo-stationary phases (PSPs) exist, such as cyclodextrins [39], dendrimers [40], proteins [41], liposomes [42], ionenes [43], siloxanes [44] micelles [3, 38] and microemulsions [45]. Comparisons between MEEKC and MEKC are often made, as their separation basis is similar [46-48]. In MEKC, surfactant molecules form micelles and solutes dissolve in them, which facilitates separation. Solutes can penetrate a microemulsion droplet more easily than a more rigid micelle and the loadability of a droplet compared with a micelle is much higher. 

Dendrimers are polymeric molecules composed of multiple branched monomers radially emanating from a central core. Dendrimers based on polymers such as polyamidoamines (PAMAMs) and poly(propylene imine) can form compact polycations under physiological conditions and, therefore, have been of interest to researchers for use in gene delivery both in vivo and in vitro [78,89,90]. They can also be functionalized with other molecules such as a-cyclodextrin [91], PEG [92], etc. to enhance gene integration and expression. However, the use of dendrimers for in vitro gene delivery into somatic and stem cells has not yet been demonstrated. 

The versatile inclusion phenomena exhibited by the family of cyclodextrin (CD) macrocycles have been harnessed to produce supramolecular dendrimers and hyper-branched polymers. An early demonstration of exorecognition that resulted in an electroresponsive supramolecular dendrimer was published by Kaifer and coworkers in 1997 (Scheme 2). The group produced a series of polypropylene imine (PPI) " dendrimers (from the first to the fourth generation) that were decorated with cobaltacene residues at the periphery. In their multiply charged state (2), the... 

For longer polymers, adsorption and film formation can take place in organic solvents, which are good solvents for the neutral ferrocene-based species but bad solvents for the oxidized species [153, 154, 160-165]. In this case, even diblock copolymers precipitate on the electrode, without indication of the formation of micellar structures upon electrochemical switching [166-168]. Co-precipitation with carbon nanotubes onto electrodes has been achieved [169]. As a matter of fact, common solvents for both redox states are seldom available, unless the hydrophobic ferrocene units are complexed by cyclodextrins (in this case, water is a good solvent) [170, 171]. As another example, dendritic ferrocene-based polymers are sufficiently solubilized, even after oxidation in organic media (probably, the insoluble units are shielded in the interior of the dendrimers) [172]. Star-like... 

Nonviral synthetic vectors (cationic liposomes/polymers, dendrimers, cyclodextrin, ceU-penetrating peptides) Vector can cross cell membrane Easy to handle Technically simple Low transfection efficiency and toxicity in certain cases Yes It is possible to perform site directed injections (microinjections)... 

For DNA and RNA delivery to the central nervous system (CNS), numerous nonviral nanosystems can be employed [10], These include cationic and stealth liposomes, cationic polymers, dendrimers, cyclodextrin, and cell-penetrating peptides (CPPs). In general terms, all these synthetic vectors lack of a cytotropism, i.e., they do not specifically target a single type/subtype of cell, and display different degrees of cytotoxicity. 

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