Magnetic dextran-spermine nanoparticles as pH-sensitive carriers for antibiotic delivery

In recent decades, extensive research has been conducted on nano drug delivery systems for treating inflammation. Despite this, the lack of specificity in many carriers and materials has hindered their effectiveness in enhancing treatment efficiency. To address this challenge, among numerous candidate biomaterials, stimuli-responsive biopolymers have received significant interest for precisely delivering their payload to inflamed tissues. Herein, to overcome this deficiency, pH-responsive magnetic nanocarriers were fabricated. A cationic dextran was synthesized based on the oxidation of glucose ring and conjugation of spermine. Drug-loaded magnetic dextran-spermine nanoparticles (DS-NPs) were prepared by in situ drug loading via ionic gelation. Fabricated nanoparticles have smaller size (60–100 nm), with relatively narrow size distribution (pdI = 0.175–0.251), and a positive surface charge (+ 17.1 to + 29.0 mV). The in vitro release study in simulated normal and inflamed organ environments confirmed the pH sensitivity of the drug release with a slight burst effect in normal conditions and accelerated release in acidic pH (final release < 70% and < 50% of the total encapsulated drug for pH 7.4 and pH 5.0, respectively). Antibacterial study on Staphylococcus aureus showed no changes in the bactericidal activity of encapsulated vancomycin. Cytotoxicity studies on HUVEC cells confirmed that drug-free nanoparticles exhibited no toxicity, even up to 1 mg/mL. Furthermore, the cytotoxicity of encapsulated vancomycin against HUVEC cells was lower than that of free vancomycin in all incubation times (24 h, 48 h, 72 h).