Phage-coated vinorelbine-loaded hexagonal boron nitride for targeted lung cancer therapy via chemo-photothermal...

Lung cancer remains one of the most widespread and difficult-to-treat malignancies, with current treatments approaches often lacking specificity and resulting in significant off-target toxicity. Nanoparticle-based drug delivery systems (DDS) have emerged as a promising strategy to overcome these limitations. Hexagonal boron nitrides (h-BN) nanoparticles (NPs) have gained attention due to their high photothermal (PT) conversion efficiency and versatile surface functionalization capabilities, making them attractive candidates for targeted cancer therapy. In this study, we successfully developed a novel DDS synthesizing phage-coated vinorelbine (VB)-loaded h-BN NPs, denoted as VB-h-BN@Phage, for enhanced lung cancer treatment. TEM revealed that the VB-h-BN@Phage were spherical, with an average size of 290 nm, while zeta potential analysis showed a surface charge of -25.3 mV, indicating good colloidal stability. We evaluated the viability and bioactivity of T4 bacteriophage following conjugation with VB-h-BN, revealed a slight reduction in phage titer (8.9 ± 0.5 × 10¹⁰ PFU/mL), suggesting minor steric. ELISA confirmed successful phage loading, with VB-h-BN@T4 maintaining high absorbance (1.42 ± 0.36) comparable to phage (1.55 ± 0.65), indicating preserved bioactivity. The h-BN NPs exhibited excellent NIR-responsive energy conversion, enabling VB-h-BN@Phage to achieve a high PT conversion efficiency (η = 53.2%). Cytotoxicity assay showed significant antiproliferative effects of VB-h-BN@Phage against A549 lung cancer cells, with an IC₅₀ of 42 μg/mL of chemo-PTT approach. TEM revealed efficient endocytic uptake of h-BN and VB-h-BN@Phage NPs, indicated that NPs were entered cells via endocytosis, with enhanced uptake observed under NIR, and confirming internalization. Flow cytometry analysis revealed that VB-h-BN@Phage exhibited enhanced antitumor potential. In vivo results, the chemo-PTT treatment group exhibited the most pronounced tumor suppression, with the smallest average tumor volume (89.6 mm³) and lowest tumor weight (0.29 g). In serum cytokine, native T4 phage triggered a strong innate immune reaction, with significantly elevated levels of TNF-α, IL-6, IFN-γ, and MIP-1β/CCL4. We investigated the immunogenicity of VB-h-BN@Phage in BALB/c mice over 42 days. Anti-T4 phage-specific IgM, IgG, and IgA responses were analyzed; VB-h-BN@Phage group indicated significantly lower titers, suggesting partial coating of phage epitopes by VB-h-BN. In silico studies revealed strong binding affinities of VB to cancer-related targets: TACR2, CYP3A4, and ABCB1, with binding energies of -5.9, -11.2, and -7.8 kcal/mol, respectively. Molecular docking further confirmed that the VB-h-BN@Phage conjugate retained significant binding capacity to these targets, with only slight reduction compared to VB.