Micellar Formation of Poly(caprolactone-block-ethylene oxide-block- caprolactone) and Its Enzymatic Biodegradation in Aqueous Dispersion

Abstract

The water-insoluble triblock copolymer poly( -caprolactone-b-ethylene oxide-b--caprolactone) (PCL-b-PEO-b-PCL) can form core-shell-like polymeric micelles in aqueous solution where the core and shell are respectively made of collapsed hydrophobic PCL and swollen hydrophilic PEO blocks. Four PCLb-PEO-b-PCL triblock copolymers with different PEO/PCL molar ratios were prepared and characterized. The degradation of these copolymer micelles in the presence of enzyme lipase PS was much faster than the bulk PCL or PCL thin film. The degradation kinetics was investigated using a combination of laser light scattering and pH measurements. The results revealed that the in-situ biodegradation of the copolymer chains inside the micelle could be effectively monitored by a pH meter, while laser light scattering measures the biodegradation-induced dissociation of the micelles in water. The effects of the enzyme and copolymer concentrations as well as the PCL/PEO molar ratios on the biodegradation kinetics were studied.

Synthesis of a Novel Electroactive ABA Triblock Copolymer and its Spontaneous Self‐Assembly in Water

“…1 H and 13 C nuclear magnetic resonance (NMR) spectra were recorded on a Bruker AV 400 MHz spectrometer with DMSO-d 6 as the solvent at room temperature. Mass spectroscopy (MS) was performed on an AXIMA-CFR laser desorption ionization flying-time spectrometer (COMPACT).…”

“…[5] The most commonly-studied block copolymer used for micellar drug delivery is poly(ethylene oxide) (PEO)-block-biodegradable aliphatic polyester (such as poly (e-caprolactone) (PCL) and poly(lactic acid) (PLA)). [6][7][8][9][10][11] PEO comprises the hydrophilic block, and the aliphatic polyesters form the hydrophobic block. In aqueous solutions, the amphiphilic block copolymers can selfassemble into nanoscale shell-core micelles with the hydrophilic PEO block becoming the shell of micelle, similar to conventional amphiphilic surfactants.…”

Macromolecular monomers for the synthesis of hydrogel niches and their application in cell encapsulation and tissue engineering

“…Numerous groups are interested in exploiting the photoinitiated polymerization of poly (ethylene glycol) (PEG)-based macromolecular monomers to create hydrogels for applications ranging from cell delivery vehicles [ 2,15,16,18,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] for tissue regeneration to in situ forming tissue adhesives [33][34][35] . In many of these biomaterial applications, degradation of the final gel is desired, and the mechanism of degradation and subsequent mass loss profile are critical parameters that dictate the usefulness of the material for its intended application.…”

Nanostructured Morphologies by Self-Assembly of Diblock Copolymers: A Review

“…As a result, χN represents the enthalpy related to the linkage of two different polymer chains. In thin films of block copolymers, the orientation and lateral ordering of the microdomains are influenced by factors like χN, interfacial interactions at the air/polymer and polymer/substrate interfaces, and the commensurability between the equilibrium period (L o ) and film thickness [12,13]. A parallel orientation of the cylindrical and lamellar microdomains is observed when there is a large difference in the surface energies of the two blocks and/or a strong preferential interaction of one block with the substrate.…”