Indocyanine green-laden poly(ethylene glycol)-block-polylactide (PEG-b-PLA) nanocapsules incorporating reverse micelles: Effects of PEG-b-PLA composition on the nanocapsule diameter and encapsulation efficiency

Abstract

Reverse micelles are thermodynamically stable systems, with a capacity to encapsulate hydrophilic molecules in their nanosized core, which is smaller than the core generally obtained with water-in-oil-emulsion droplets. Herein, we present a simple technique for the preparation of poly(ethylene glycol)-block-polylactide (PEG-b-PLA) nanocapsules encapsulating a hydrophilic photosensitizer (indocyanine green, ICG), which exploits reverse micelle formation and subsequent emulsion-solvent diffusion. We establish the effect of the PEG-b-PLA composition and the co-surfactant volume on the diameter and water content of the reverse micelles. We demonstrate that the composition of PEG-b-PLA affects also the diameter and encapsulation efficiency of the resulting nanocapsules. We show that the ICG-laden nanocapsules fabricated under the most optimal conditions have a diameter of approximately 100 nm and an ICG encapsulation 3 efficiency of 58%. We believe that the method proposed here is a promising step towards the preparation of hydrophilic drug-laden polymer nanocapsules with a small diameter and therefore suitable for use in drug delivery applications based on enhanced permeability and retention (EPR) effect-driven passive targeting.

PEGose Block Poly(lactic acid) Nanoparticles for Cargo Delivery

“…These values are similar to the ζ potential values reported for PEG- b -PLA nanoparticles, usually ranging between −2.0 and −11.0 mV. 52 , 60 The low absolute value of the ζ potential (less than 30 mV) might be a reason for the aggregation over time of the nanoparticles. However, extruding the nanoparticle solution through a 0.2 μm filter yielded nanoparticles with the same size as when they were initially formed.…”

“…The size of the nanoparticles tended to increase over time, presumably due to aggregation. Thus, ζ potential measurements were performed on PEGose 50 -b-PLA 50 52,60 The low absolute value of the ζ potential (less than 30 mV) might be a reason for the aggregation over time of the nanoparticles. However, extruding the nanoparticle solution through a 0.2 μm filter yielded nanoparticles with the same size as when they were initially formed.…”

Microfluidic Formation of Hydrogel Microcapsules with a Single Aqueous Core by Spontaneous Cross-Linking in Aqueous Two-Phase System Droplets

“…Microcapsules having a large aqueous core are attractive vehicles for the delivery of pharmaceuticals and biologically active species, − as well as for cell encapsulation. − Various techniques, including interfacial reaction, co-extrusion, ,, solvent evaporation from double emulsions, − and deposition of polyelectrolyte layers on a sacrificial particle, , are used to fabricate microcapsules. In particular, the most common way for the preparation of hydrogel microcapsules having an aqueous core and a semipermeable hydrogel shell is to employ a co-extrusion of core–shell droplets in air followed by a sol–gel transition of the shell after immersion of them into a gelling bath.…”

Construction of poly(ethylene glycol)-poly(L-lactic acid)-stearic acid aspirin-loaded reverse micelles and optimization of preparation process

“…Stearic acid is the main component of fat, which has the characteristics of good biocompatibility and low cyotoxicity [ 20 ]. So far, the preparation of micelles is usually done by emulsion-solvent evaporation or emulsion-solvent diffusion, but these techniques are only suitable for encapsulating hydrophobic drugs [ 21 ]. Such forward micelles that can dissolve nonpolar compounds have been extensively studied.…”