pH- and Thermo-Responsive Water-Soluble Smart Polyion Complex (PIC) Vesicle with Polyampholyte Shells

Abstract

A diblock copolymer (P(VBTAC/NaSS)17-b-PAPTAC50; P(VS)17A50) composed of amphoteric random copolymer, poly(vinylbenzyl trimethylammonium chloride-co-sodium p-styrensunfonate) (P(VBTAC/NaSS); P(VS)) and cationic poly(3-(acrylamidopropyl) trimethylammonium chloride) (PAPTAC; A) block, and poly(acrylic acid) (PAAc49) were prepared via a reversible addition−fragmentation chain transfer radical polymerization. Scrips V, S, and A represent VBTAC, NaSS, and PAPTAC blocks, respectively. Water-soluble polyion complex (PIC) vesicles were formed by mixing P(VS)17A50 and PAAc49 in water under basic conditions through electrostatic interactions between the cationic PAPTAC block and PAAc49 with the deprotonated pendant carboxylate anions. The PIC vesicle collapsed under an acidic medium because the pendant carboxylate anions in PAAc49 were protonated to delete the anionic charges. The PIC vesicle comprises an ionic PAPTAC/PAAc membrane coated with amphoteric random copolymer P(VS)17 shells. The PIC vesicle showed upper critical solution temperature (UCST) behavior in aqueous solutions because of the P(VS)17 shells. The pH- and thermo-responsive behavior of the PIC vesicle were studied using 1H NMR, static and dynamic light scattering, and percent transmittance measurements. When the ratio of the oppositely charged polymers in PAPTAC/PAAc was equal, the size and light scattering intensity of the PIC vesicle reached maximum values. The hydrophilic guest molecules can be encapsulated into the PIC vesicle at the base medium and released under acidic conditions. It is expected that the PIC vesicles will be applied as a smart drug delivery system.

Chitosan-Based Smart Biomaterials for Biomedical Applications: Progress and Perspectives

“…Such a bond leads to adhesion with the mucus layer and prolongs the residence time of insulin in the gut . Nowadays, PECs indeed are one of the promising nanoparticles for drug carriers because of their simple preparation. , Chitosan-based PECs fabricated using a simple mixing method of chitosan with poly-2-acrylamido-2-methylpropanesulfonic acid (PAMPS) also demonstrated a sufficient electronic interaction. The result showed that the net surface charge and the particle size are dependent on the amount of chitosan, whereas a negative zeta potential is defined as a better option for drug carriers because it could prolong circulation time in the bloodstream and less interaction with macrophages …”

Polyampholyte Polymers‐Based Sensors: A Review on Stimuli and Applications

“…This structure had potential for drug delivery as hydrophilic molecules can be enclosed in the vesicle and released in acidic environments at pH < 7 (Figure 10). [69] To investigate the electrical potential and osmotic pressure responses of hemoglobin-loaded polyampholyte hydrogels, Goh et al developed a detailed multiphysics model that takes into account interactions between immobilized functional groups in the hydrogel and the salt-loaded media. They described the impact of pH-and oxygen-coupled stimuli on osmotic pressure and electrical potential responses of hemoglobin-loaded polyampholyte hydrogel.…”

“…Herein, a multiphysics model is developed for elucidating the multi-physical interaction between immobile functional components bounded onto polymeric network chains of the hydrogel and hydrogen ion/oxygen-enriched environmental solution. Two constitutive relationships are incorporated into the model: 1) ionization of fixed charge group as a function of its ionization strength coupled with hydrogen ion concentration and 2) bioac- [69] Copyright 2022, MDPI.…”

“…P(VS)17A50/PAAc49 PIC vesicles were developed by Pham et al as thermoresponsive sensors. [69] The amphoteric random copolymer shell of P(VS)17 was in charge of the UCST of the generated PIC vesicles. As the temperature increased, the solution's rising light transmittance caused the solution to eventually become translucent, as seen in Figure 17b.…”

Self-Cross-Linkable Chitosan–Alginate Complexes Inspired by Mussel Glue Chemistry

“…The stability of Chi–Alg complexes in response to pH and salinity of the environment is of importance in many applications. − In the complexed state, these oppositely charged weak biopolyelectrolytes are held together mainly by electrostatic interactions; hence, variations in pH and salinity perturb the charge balance and produce swelling/dissociation . This inherent feature has been used to develop pH-responsive materials, e.g., vesicles releasing the encapsulated agent. − In many other systems though, one requires the complex to be stable against variations in pH and salt. − Herein, various chemical modifications are suggested to covalently cross-link the biopolymers by postmodification of the complex through EDC/NHS coupling or using a cross-linker such as glutaraldehyde . Such methods may not always be favorable considering the need for an extra postmodification step as well as safety concerns over using volatile toxic reagents.…”