l‑Cystine-Based\nPolyurethane as a\nDrug-Delivery Vehicle in Targeted Cancer Therapy and Biomedical Applications

Controlled and sustained drug release is a critical aspect\nof drug-delivery\nsystems (DDSs) that can be used in chemotherapy while ensuring therapy\neffectiveness and biosafety. Hence, polyurethane (PU) is modified\nusing a biomolecule Cystine (CYS) for protracted drug release, aiming\nto enhance cancer treatment efficacy while minimizing adverse side\neffects in tumor patients. To confirm the formation of a polymer structure,\ncharacterization techniques such as NMR and FTIR are used, and the\nmorphology is determined using SEM. Biocompatibility of the synthesized\npolymers is evaluated through cellular assessments, including MTT\nassay, cell adhesion, and antibacterial assay along with drug release\nusing an anticancer drug, Paclitaxel (PTX). Notably, the incorporation\nof PTX in the polymer matrix results in minimal mortality (85% viable\ncells) rates in healthy cells (3T3), in contrast to a 56% mortality\nrate observed with the pure drug. While PTX shows a burst release\nand kills cancer cells only for the first 24 h, PU loaded with the\ndrug shows sustained release and kills the cancer cells for 3 days.\nThis vehicle selectively kills 59% of SiHA cells after a consecutive\nstudy of 3 days, which highlights the potential of this newly designed\nvehicle for effective drug delivery, particularly in anticancer treatments.\nMoreover, cystine’s antibacterial property adds up with PU;\nhence, PU shows antibacterial activity against <i>Staphylococcus\naureus</i> (MIC, 20 μg/mL) and also acts as a reductive\noxygen species scavenger. Therefore, modifying PU with CYS has shown\nsustained release of PTX along with a selective effect on cells, underscoring\nits significance as a superior delivery agent and supported by a shred\nof convincing evidence.