A novel route for preparation of multifunctional polymeric nanocarriers for stimuli-triggered drug release

Abstract

Fluorescence-incorporated, crosslinker-free, pH-and thermoresponsive nanocarriers were prepared by the incorporation of drug molecules into the thermoresponsive nanocapsules, which composed of poly(N-isopropylacrylamide) (PNIPAAm) with carboxylic acid end groups via temperature induced self-assembling method. Well-defined, pH-responsive carboxylic acid group-ended PNIPAAm homopolymer (HOOCA PNIPAAmACOOH) was synthesized by reversible addition fragmentation chain transfer polymerization with S,S 0 -bis(a,a 0dimethyl-a 00 -acetic acid)trithiocarbonate (CMP) as a chain transfer agent. Rhodamine 6G (R6G), the model drug, was used for three kinds of application: First, the nanostructure fixing; second, the fluorescence-labeling; and last, the controlled release modeling. The transmission electron microscope images showed the solution type dosing led to the encapsulation of drug molecules into the nanocarriers, while the powder-type drug-loading process significantly contributed to the structure preservation of nanocarriers. The controlled release behaviors with various pH values and temperatures were evaluated. These multifunctional nanocarriers have potential to be applied for the biomedical therapy by stimuli-responsive controlled release.

Thermo- and pH-induced self-assembly of P(AA-b -NIPAAm-b -AA) triblock copolymers synthesized via RAFT polymerization

“…In our previous study, we synthesized the HOOC‐PNIPAAm‐COOH homopolymer (N 400 ) by RAFT polymerization using the CMP as the chain transfer agent. The N 400 was thus composed of PNIPAAm main chain with two terminal carboxylic acid groups.…”

“…Though ABA triblock copolymers of P(AA‐ b ‐NIPAAm‐ b ‐AA) have been prepared by atom transfer radical polymerization (ATRP) or RAFT polymerization for various applications such as bone tissue engineering, there are few reports focused on the influence of main‐chain composition on the self‐assembled morphologies of P(AA‐ b ‐NIPAAm‐ b ‐AA) triblock copolymers. Our previous studies indicated that not only telechelic HOOC‐PNIPAAm‐COOH homopolymer but also P(AA‐ b ‐NIPAAm‐ b ‐AA) could self‐assemble into spherical nanoparticles under specific pH value and temperature . Herein, we systematically design a series of P(AA‐ b ‐NIPAAm‐ b ‐AA) copolymers with various molar ratios of NIPAAm to AA unit via RAFT polymerization using a trithiocarbonate as the chain transfer agent (CTA).…”

Self-assembly behaviors of thermal- and pH- sensitive magnetic nanocarriers for stimuli-triggered release

“…In our previous study [ 21 ], R6G molecules had shown strong interaction with the tri-block copolymer, P(AA-b-NIPAAm-b-AA), thus the characteristic would be utilized for drug encapsulation. It is obvious that R6G not only could diffuse into the magnetic nanocarriers but also participate on the surface during the loading process as shown in Figure 5 .…”

RAFT radical copolymerization of beta‐pinene with maleic anhydride and aggregation behaviors of their copolymer in aqueous solution

“…In aqueous solution, amphiphilic block copolymers can self‐assemble into molecular aggregates with a core–shell structure which have a size from nanometer to micron level or even greater, and its morphology, which can be changed in a controllable way, would be spherical, rod‐like, layered, vesicular, etc. Over the last decade, self‐assembly behaviors of amphiphilic block copolymer in aqueous solution had attracted great interests, because these researches inaugurate new areas for the application of amphiphilic block copolymers, such as controlled release of gene and drug, microreactors for chemical synthesis or catalytic reactions …”