Quaternary ammonium substituted dextrin‐based biocompatible cationic nanoparticles with ultrahigh pH stability for drug delivery

Cationic nanoparticles (NPs) are preferred for therapeutic applications due to its better uptake by mammalian cells. However, preparing cationic polymeric NPs with stability in wide pH range along with limited toxicity remains a challenge. Dextrin, a carbohydrate‐based natural biological macromolecule holds great potential in biomedical applications. Further, it is an inexpensive and abundant raw material which has high pH stability making it more advantageous over other widely explored macromolecules like chitosan. Herein, we report a simple process for preparing biocompatible cationic dextrin (CD) NPs. A series of CDs were prepared through a single‐step reaction by incorporating quaternary ammonium groups onto the polymeric backbone using varying amount of glycidyltrimethylammonium chloride. Formation of uniform spherical CD NPs having size within 100 nm were achieved by a facile synthesis process of ionic gelation using a biocompatible cross‐linker sodium tripolyphosphate. The prepared CD NPs remained stable across the pH range of 5.5–11 and demonstrated approximately 75% cellular internalization within 6 h. The CD NPs were also found to be both cytocompatible and hemocompatible. Next, the chemotherapeutic drug doxorubicin was encapsulated within CD NPs, which is one of the most common chemotherapeutic agents used for the treatment of various types of cancers including breast, lung, ovarian and bladder. The Dox‐loaded CD NPs showed better drug release at acidic pH conditions and induced more than 80% cell death within 24 h at just 2 μg/ml concentration when tested against HeLa cell lines, thus, proving to be a potential drug delivery vehicle for cancer therapy applications.