Effect of Temperature and Hydrophilic Ratio on the Structure of Poly(N-vinylcaprolactam)-block-poly(dimethylsiloxane)-block-poly(N-vinylcaprolactam) Polymersomes

Abstract

Nanosized polymeric vesicles (polymersomes) assembled from ABA triblock copolymers of poly(N-vinylcaprolactam)-poly(dimethylsiloxane)-poly(N-vinylcaprolactam) (PVCL-PDMS-PVCL) are a promising platform for biomedical applications, as the temperature-responsiveness of the PVCL blocks enables reversible vesicle shrinkage and permeability of the polymersome shell at elevated temperatures. Herein, we explore the effects of molecular weight, polymer block weight ratios, and temperature on the structure of these polymersomes via electron microscopy, dynamic light scattering, small angle neutron scattering (SANS), and all-atom molecular dynamic methods. We show that the shell structure and overall size of the polymersome can be tuned by varying the hydrophilic (PVCL) weight fraction of the polymer: at room temperature, polymers of

Self-Assemblies of Thermoresponsive Poly(N-vinylcaprolactam) Polymers for Applications in Biomedical Field

“…66 The PVCL n -b-PDMS 65 -b-PVCL n block copolymers were obtained by RAFT polymerization. 66,67 We have shown that the copolymers could produce vesicles at ambient conditions through a cosolvent method (ethanol/water) with the vesicle size varying from 530 to 40 nm when the PVCL degree of polymerization was increased from n = 10 to n = 19. 66 The remarkable feature of these polymersomes is their reversible size changes upon solution heating (up to 50 °C) because of volume transitions of PVCL coupled to the hydrophobic PDMS which, in turn, also contributes to the reversible size modulations due to PDMS insolubility in water (Figure 9).…”

“…The PVCL n - b -PDMS 65 - b -PVCL n block copolymers were obtained by RAFT polymerization. , We have shown that the copolymers could produce vesicles at ambient conditions through a cosolvent method (ethanol/water) with the vesicle size varying from 530 to 40 nm when the PVCL degree of polymerization was increased from n = 10 to n = 19 …”

“…The results of small-angle neutron scattering (SANS) study employed to elucidate the mechanistic details of the release suggested that, during temperature-induced phase transition, the collapsed PVCL could intermingle with the inner PDMS membrane whose fluidity increased and that created regions of decreased hydrophobicity above 42 °C allowing transport of DOX molecules through the PDMS layer (Figure ). For PVCL blocks with higher degrees of polymerization, the intermixing of the PVCL chains during their collapse could provide a steric barrier (Figure ) rendering the polymersome shell denser and prohibiting PVCL intermixing with the PDMS domain and resulting in inhibition of dye passage.…”

Current Advances of Hollow Capsules as Controlled Drug Delivery Systems

“…successfully generated doxurubicin (DOX)‐loaded polymersomes in nanoscale (60 nm in diameter) by using methoxy poly(ethylene glycol)‐b‐poly(epsilon‐caprolactone) (mPEG‐b‐PCL) . The use of film hydration method for polymersome formation was still very popular, which was being scrutinized in recent reports . However, the uniformity of synthesized capsules was not high and the modification of hollow capsules prepared by this method was not feasible.…”

“…[31] The use of film hydration method for polymersome formation was still very popular, which was being scrutinized in recent reports. [32][33][34] However, the uniformity of synthesized capsules was not high and the modification of hollow capsules prepared by this method was not feasible.…”