Self-consistent field predictions for quenched spherical biocompatible triblock copolymer micelles

Abstract

We have used the Scheutjens-Fleer self-consistent field (SF-SCF) method to predict the self-assembly of triblock copolymers with a solvophilic middle block and sufficiently long solvophobic outer blocks. We model copolymers consisting of polyethylene oxide (PEO) as solvophilic block and poly(lactic-co-glycolic) acid (PLGA) or poly(ǫ-caprolactone) (PCL) as solvophobic block. These copolymers form structurally quenched spherical micelles provided the solvophilic block is long enough. Predictions are calibrated on experimental data for micelles composed of PCL-PEO-PCL and PLGA-PEO-PLGA triblock copolymers prepared via the nanoprecipitation method. We establish effective interaction parameters that enable us to predict various micelle properties such as the hydrodynamic size, the aggregation number and the loading capacity of the micelles for hydrophobic species that are consistent with experimental finding.

Design of block-copolymer-based micelles for active and passive targeting

“…It was found that by implementing a model wherein segments are represented as amorphous beads, i.e. A 60 B 60 A 60 (PLGA 60 PEO 60 PLGA 60 ; 7.5-6.0-7.5 kDa), there exists a set of interaction parameters that leads to structural properties of micelles that compare favourably with the ones found experimentally using the solvent precipitation method [21]. Once such micelles have formed, we envision that the core becomes unresponsive, i.e.…”

“…The method employed, the Scheutjens-Fleer self-consistent field (SF-SCF) theory [16][17][18], successfully used earlier to theoretically study the triblock copolymer micelle structure and stability [19,20]. It was found that by implementing a model wherein segments are represented as amorphous beads, i.e.…”

Controlled block copolymer micelle formation for encapsulation of hydrophobic ingredients

“…8 of our recent paper [36], we investigated whether a hydrophobic polymeric excipient with a chemical composition similar to the hydrophobic blocks of the copolymers used can be encapsulated. In this way we determined the loading capacity/capability and the relation between excipient weight percentage and (hydrodynamic diameter) size.…”

“…Indeed, during the precipitation procedure we expect the driving force to be an increasing function of the time after the addition of the selective solvent. In the SF-SCF modeling [36] we have simplified this process by taking a simple selective solvent, which presents a moderate driving force for micellisation. This leads to predictions in trends in micelle size and molecular weight which can directly be tested experimentally.…”

“…The method and results are explained in [36]. SF-SCF is known to be very accurate for densely packed polymer systems including micellar structures [37][38][39][40].…”