Synthesis and properties of a novel bolaamphiphile surfactant derived from proline

A novel bolaamphiphile surfactant N,N0-（octane-1,8-diyl）bis（pyrrolidine-2-carboxamide）（DAOP）, was designed and synthesized from proline and 1,8-diaminooctane, as the hydrophilic part and hydrophobic part, respectively. After separation and purification, the structures of the synthesized bola surfactants were verified by IR, MS and-1 H NMR. The p Kawas measured by a titration experiment, the turbidity was determined using a Shimadzu UV-1750 spectrophotometer, and the critical micelle concentration（CMC）values of the synthesized surfactants in water were obtained using the conductivity and fluorescence probe measurements. The synthesized bolaamphiphile surfactants demonstrate the ability of selfassemble to form vesicles that were confirmed with dynamic light scattering and transmission electron microscopy. The results showed that the novel bolaamphiphile surfactant derived from proline might potentially be an excellent carrier for drug delivery.

Novel Cyclopeptide Bolaamphiphile for Constructing Supramolecular Nanotubes

A novel dicyclopeptide-based bolaamphiphile was synthesized.The hydrophilic cyclopeptide fragments were linked to an alkyl chain 1,6-bis(maleimido)hexane,which acted as a hydrophobic spacer.The transmission electron microscopy (TEM) observation indicated that the cyclopeptide bolaamphiphile (CPB) self-assembled into the nanotubes with a thickness of about 3 nm.Based on the optimized molecular conformation obtained via MM2 method,the length of CPB was demonstrated to be around 4 nm,implying that the nanotubes were single-walled.Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) analysis showed that the cyclopeptides in CPB mainly acted as the hydrophilic headgroups,rather than providing the well-ordered hydrogen bonding interaction responsible for β-sheet conformation.To investigate the special self-assembly behavior of CPB,the single cyclopeptide (CP) without the connection of the linker was synthesized.Further investigation indicated that the CP molecules can not form tubular structures but nanofibers.

Supramolecular assemblies from single-chain hydrocarbon fluorocarbon hybrid bolaamphiphiles

Three types of single-chain hydrocarbon fluorocarbon hybrid bolaamphiphiles were synthesized. They readily formed different kinds of organized supramolecular assemblies, including vesicles, tapes, and micellar fibers, in aqueous solution. The aggregates morphology was characterized by transmission electron microscopy (TEM) after negative staining. The superstructures of these aggregates seemed to be determined by the geometry and the head group's properties of the corresponding amphiphiles..

A New Type of Deaggregators, the Bolaamphiphilic DeAgrs. Observations of the Dependence of Deaggregating Ability on Aggregator Concentration and Solvent Aggregating Power

Four new amphiphilic molecules, i.e., the bolaamphiphiles n-trimethylamino n-hexadecanoate (deAgr 16), n-dodecanoate (deAgr 12), n-undecanoate (deAgr 11), and n-octanoate (deAgr 8) were synthesized. Their ability as deaggregators to break up the aggregating systems of hexadecyl β-naphthoate (A16) and dodecyl β-naphthoate (A12) in dioxanewater binary solvent systems was investigated in a number of solvent systems and at different A16 and A12 concentrations. The results reveal that this new type of bolaamphiphilic molecules appears to be one of the most efficient deaggregators reported, which, at very low concentrations, can effectively break up the aggregating systems of highly concentrated A16 and A12. It is also found that bolaamphiphfles with longer aliphatic chains possess greater deaggregating ability. However, when the overall concentrations of A16 and A12 are very low but still above their critical aggregating concentration, these bolaamphiphilic molecules lose their deaggregating power and tend to coaggregate with the aggregated A16 or A12 molecules. The quite efficient deaggregating ability of the long-chain bolaamphiphfles (deAgr 16 and deAgr 12), as compared to the short-chain deAgr 8, has been ascribed to their dynamic switch-on/switch-off behavior involving coiled-up and uncoiled conformations of their long aliphatic chains.