Core–Shell–Corona Micelles from a Polyether-Based Triblock Terpolymer: Investigation of the pH-Dependent Micellar Structure

Abstract

Core-shell-corona micelles featuring a pH-responsive shell have been characterized in dilute aqueous solution at different pH values (4-8) by using dynamic light scattering (DLS), field-flow fractionation coupled with multiangle light scattering detector (FFF-MALS), steady-state fluorescence, small-angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM). The micelles are formed by self-assembly of a polyether-based triblock terpolymer consisting of a hydrophobic poly( tert-butyl glycidyl ether) block (P tBGE), a pH-responsive modified poly(allyl glycidyl ether) segment (PAGE), and a neutral hydrophilic poly(ethylene oxide) block (PEO). Because of the side-chain carboxylic acids in the middle block, the micellar structure and size depends on the solution pH. Hereby, we show that an increase in pH induces a decrease in the aggregation number ( N). In addition, the combination of the above measurements revealed an unexpected morphological change from spherical to ellipsoidal micelles by increasing pH.

Asymmetric flow field-flow fractionation as a multifunctional technique for the characterization of polymeric nanocarriers

“…For example, batch DLS was able to detect the aggregates present in a formulation of poly(lactic-coglycolic acid) (PLGA) nanoparticles, while said aggregates disappeared when the formulation was analyzed by SdFFF due to the spatial separation among solutes [76]. In a similar fashion, excessively high flows could induce particle disruption due to shear forces [77].…”

Chain extension epoxide polymerization to well‐defined block polymers using a N‐Al Lewis pair catalyst

“…Polyethers are widely used in drug and vaccine delivery and as polymer electrolytes and non-ionic surfactants. [1][2][3][4][5][6][7][8][9][10] Poloxamer materials are a particular subset of non-ionic, ABA block polyethers containing a central hydrophobic PPO block flanked by two outer hydrophilic poly(ethylene oxide) (PEO) blocks (i.e., PEO-b-PPO-b-PEO). Other poloxamer-like materials with diverse architectures have been developed with the same design strategy of a hydrophobic midblock with PEO outer blocks on either side.…”

“…7,14 Unfortunately, many studies utilizing BAB triblock polymers focus on polymers with relatively short end blocks compared to their poloxamer counterparts. 10,[15][16][17][18][19][20][21] Jung et al showed that simply tuning the hydrophobicity of BAB triblocks by altering the hydrophobic block composition could significantly alter hydrogel relaxation dynamics; however, none of their hydrophilic end blocks exceeded 3.0 kg/mol in total. 16 Even traditional PPO-b-PEO-b-PPO RP materials such as the commercially available 25R4 and 31R1 RPs are lower molecular weight (ca.…”

“…Polyethers are widely used in drug and vaccine delivery and as polymer electrolytes and non‐ionic surfactants 1–10 . Poloxamer materials are a particular subset of non‐ionic, ABA block polyethers containing a central hydrophobic PPO block flanked by two outer hydrophilic poly(ethylene oxide) (PEO) blocks (i.e., PEO‐ b ‐PPO‐ b ‐PEO).…”

“…[11][12][13] In recent years, the prevalence of these polymer architectures has increased with the rising need for materials with more complex polymer architectures for drug delivery, surfactant, electrolyte, and structural applications. [8][9][10] Reverse poloxamers (RPs) are BAB triblock materials with hydrophilic midblocks surrounded on both sides by hydrophobic outer blocks. RPs have been successfully demonstrated as potential drug delivery vehicles in both in vivo and in vitro studies.…”