Design of Polymeric Nanoparticles for Theranostic Delivery of Capsaicin as Anti‐Cancer Drug and Fluorescent Nitrogen‐Doped Graphene Quantum Dots

Abstract In recent years, multifunctional nanocarriers that provide simultaneous drug delivery and imaging have attracted enormous attention, especially in cancer treatment. In this research, a biocompatible fluorescent multifunctional nanocarrier is designed for the co‐delivery of capsaicin (CPS) and nitrogen‐doped graphene quantum dots (N‐GQDs) using the pH sensitive amphiphilic block copolymer (poly(2‐ethyl‐2‐oxazoline)‐ b ‐poly(ε‐caprolactone), PEtOx‐ b ‐PCL). The effects of the critical formulation parameters (the amount of copolymer, the concentration of poly(vinyl alcohol) (PVA) as a stabilizing agent in the inner aqueous phase, and volume of the inner phase) are evaluated to achieve optimal nanoparticle (NP) properties using Central Composite Design. The optimized NPs demonstrated a desirable size distribution (167.8 ± 1.4 nm) with a negative surface charge (−19.9 ± 0.4) and a suitable loading capacity for CPS (70.80 ± 0.05%). The CPS & N‐GQD NPs are found to have remarkable toxicity on human breast adenocarcinoma cell line (MCF‐7). The solid fluorescent signal is acquired from cells containing multifunctional NPs, according to the confocal microscope imaging results, confirming the significant cellular uptake. This research illustrates the enormous potential for cellular imaging and enhanced cancer therapy offered by multifunctional nanocarriers that combine drug substances with the novel fluorescent agents.