RAFT Synthesis of Self-Assembled Poly(Acrylic Acid)-b-poly(N-Acryloyl-L-Tryptophan) Polymer: Investigating Micelle Formation and Biocompatibility

Abstract

Purpose: This study aims to synthesize and evaluate the physicochemical and biological properties of poly(acrylic acid) (PAA) and its block copolymer with N-acryloyl-L-tryptophan (PNALT), specifically focusing on their suitability for biomedical applications. Methods: PAA and PAA-b-PNALT were synthesized via RAFT polymerization using benzyl dodecyl trithiocarbonate (BDTTC) as the chain transfer agent (CTA). Kinetic studies were performed using 1H NMR to monitor acrylic acid (AA) conversion. Molecular weight evolution and polymer dispersity were analysed by GPC. Thermal behaviour was evaluated by TGA and DSC, while micelle formation was assessed using DLS and TEM. Cytotoxicity was evaluated on RAW 264.7 and MCF-7 cell lines via MTT assay. Results: The polymerization followed pseudo-first-order kinetics with a linear increase in molar mass and narrow PDI. PAA-b-PNALT exhibited enhanced thermal stability compared to PAA, as shown by TGA. No distinct Tg was observed in DSC, suggesting stability between 25–130°C. DLS and TEM confirmed self-assembly of PAA-b-PNALT into spherical micelles (80–220 nm). MTT assays demonstrated good cytocompatibility of both polymers, with PAA-b-PNALT showing improved biocompatibility, particularly at 50 µM on MCF-7 cells. Conclusion: PAA-b-PNALT exhibits desirable features such as controlled molar mass, thermal stability, self-assembly into micelles, and enhanced cytocompatibility. These properties position it as a promising candidate for applications in drug delivery, tissue engineering, and related biomedical technologies. © 2025 Wiley-VCH GmbH.