Phenylboronic acid-functionalized F127-oligochitosan conjugate micelles for doxorubicin encapsulation

Chitosan-based nanoscale systems for doxorubicin delivery: Exploring biomedical application in cancer therapy

Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS-based nanoparticles (CS-NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS-NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P-glycoprotein (P-gp) to reverse drug resistance. These nanoarchitectures can provide co-delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co-loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid-, carbon-, polymeric- and metal-based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS-NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS-NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH-sensitive release of DOX can occur. Furthermore, redox- and light-responsive CS-NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS-NPs, we expect to soon see significant progress towards clinical translation.

Phenylboronic acid-modified polymaleic anhydride-F127 micelles for pH-activated targeting delivery of doxorubicin

Phenylboronic acid (PBA) is a tumor-targeting molecule which selectively recognizes sialic acid (SA) overexpressed in tumors. In the study, PBA, F127 and ethanolamine were conjugated with poly(maleic anhydride) by one-step reaction to form amphiphilic polymer for doxorubicin encapsulation. Two drug-carrying micelles with different mass ratio of polymer to drug were prepared by dialysis method to study effect of PBA on doxorubicin release, tumor-targeting and antitumor activity. The study results showed that doxorubicin release from the formulations was acid-sensitive and affected by the polymer dosage, and its acid-induced release behavior improved its insertion into DNA base pairs. Formulation with high polymer dosage showed better tumor targeting and antitumor activity, and activity of inhibiting HepG2 with higher content of SA-containing glycosphingolipids was higher than that of anti-B16. In vivo studies on the activity of B16-bearing mice showed that the doxorubicin-loaded micelles could inhibit the tumor growth and were safer than free doxorubicin. Thus, the PBA-modified nano-polymer micelles have potential biomedical applications due to their nanostructure and tumor-targeting ability.

Chitosan Functionalization: Covalent and Non-Covalent Interactions and Their Characterization

Chitosan (CS) is a natural biopolymer that has gained great interest in many research fields due to its promising biocompatibility, biodegradability, and favorable mechanical properties. The versatility of this low-cost polymer allows for a variety of chemical modifications via covalent conjugation and non-covalent interactions, which are designed to further improve the properties of interest. This review aims at presenting the broad range of functionalization strategies reported over the last five years to reflect the state-of-the art of CS derivatization. We start by describing covalent modifications performed on the CS backbone, followed by non-covalent CS modifications involving small molecules, proteins, and metal adjuvants. An overview of CS-based systems involving both covalent and electrostatic modification patterns is then presented. Finally, a special focus will be given on the characterization techniques commonly used to qualify the composition and physical properties of CS derivatives.

Maleimide-functionalized phospholipid/Pluronic F127 mixed micelles for efficient ophthalmic delivery of voriconazole against Candida albicans

Drugs that are topically applied on the eyes have low bioavailability, which has always been an important problem. In this study, maleimide functionalized, voriconazole (VCZ) loaded mixed micelles (Mal-VCZ-MM) were designed. Pluronic F127 and phospholipid were used as materials, and maleimide was used as an adhesive. The prepared Mal-VCZ-MM was nearly spherical with a particle size of 84.45 ± 1.39 nm and a zeta potential of - 20.3 ± 0.29 mV. The encapsulation efficiency of Mal-VCZ-MM was 95.33 ± 0.06%, and it had high stability with a critical micelle concentration value of 1.28 × 10^-4 mg/mL. CCK-8 assay showed that its cytotoxicity was lower than that of free VCZ solution (VCZ-Sol). Both quantitative and qualitative analyses of the HCE-T cellular uptake showed that the cellular internalization of Mal-C6-MM was significantly stronger than that of C6-MM. The endocytosis pathway was macropinocytosis-mediated, cavernous-mediated, and energy-dependent. In vitro results against Candida albicans showed that the diameters of the antifungal inhibition zones of VCZ-Sol, VCZ-MM, and Mal-VCZ-MM were 15.5 ± 0.50 mm, 24.0 ± 0.71 mm, and 31.5 ± 1.12 mm, respectively. The antifungal effect of Mal-VCZ-MM was significantly higher than that of VCZ-Sol and VCZ-MM (P < 0.001). This study shows that Mal-VCZ-MM is a highly effective hydrophobic ophthalmic drug-delivery carrier that can improve the therapeutic effect of the drug.