Temperature-Sensitive Dendritic Micelles

Abstract

Syntheses up to three generations have been achieved of biaryl-based amphiphilic dendrons with a charge-neutral pentaethylene glycol as the hydrophilic part and a decyl chain as the hydrophobic part. Studies on the temperature-dependent characteristics revealed that these dendrons exhibit a generation-dependent lower critical solution temperature (LCST). This behavior is attributed to the combination of the amphipathic nature of the hydrophilic pentaethylene glycol side chain and dendritic effect. Interestingly, this biaryl-based scaffold also maintains the ability to form a micelle-like assembly in polar solvents and an inverted micelle-like assembly in apolar solvents. Polarity of the dendritic interior was investigated using dye-based microenvironment studies. The aggregation behavior of these micelles was analyzed by fluorescence spectroscopy and dynamic light scattering. Critical micelle concentrations (CMC) of these assemblies were investigated using fluorescence excitation spectra of the sequestered guest molecule, pyrene.

Double-degradable responsive self-assembled multivalent arrays – temporary nanoscale recognition between dendrons and DNA

“…3 The use of self-assembly endows these ligand arrays with simple 30 synthesis, 4 gives a real degree of morphological control over the assembly, 5 and through co-assembly methods can easily generate multi-component multi-functional materials. 6 Furthermore, SAMul has a greater dynamic character than covalent multivalency, and provides the potential for such arrays to 35 respond to stimulus.…”

Thermoresponsive hyperbranched polyethylenimines with isobutyramide functional groups

“…Only very recently, perfectly branched and welldefined dendrimers exhibiting the LCST in aqueous media were addressed, and the LCSTs were significantly dependent on the spheroid-like geometry of dendrimers. [12][13][14][15] Dendrimers and their less-defined hyperbranched analogues are attracting tremendous interest at present due to their specific spheroid-like shape and multifunctionality, which are powerful motifs in the design of new molecular and supramolecular structures. [16][17][18][19][20][21][22] The procedures for the syntheses of structure-perfect dendrimers are usually multistep and time-consuming, which currently limits their practical use.…”

“…[18][19][20][21][22] The attachment of some specific functional groups to the periphery of the spheroid-like dendrimers can render them thermoresponsive in aqueous media. [12][13][14][15] Since dendrimers and hyperbranched polymers have obviously topological difference in the location of end-groups, it is uncertain whether hyperbranched polymers with the same functional groups as dendrimers are also thermoresponsive. Even though the hyperbranched polymers also exhibited thermoresponsive property in aqueous media, their property should be different with that of their structure-perfect analogues, dendrimers, due to the obvious topological difference.…”

Environmental-Sensitive Hyperbranched Polymers as Drug Carriers

“…Thayumanavan and co-workers [41] synthesized biaryl-based amphiphilic dendrons with a charge-neutral pentaethylene glycol as the hydrophilic part and a decyl chain as the hydrophobic part (Fig. 6).…”

“…Interestingly, this biaryl-based scaffold also maintains the abil- Figure 6. Structure of biaryl-based amphiphilic dendrons with a charge-neutral pentaethylene glycol as the hydrophilic part and a decyl chain as the hydrophobic part [41]. ity to form a micelle-like assembly in polar solvents and an inverted micelle-like assembly in apolar solvents.…”