Herein we present the synthesis of a polymeric prodrug nanomaterial capable of spontaneous, self-assembled nanoparticle formation and of the conjugation (encapsulation) of drugs with amino and/or carboxyl and/or hydroxyl groups via ester and/or amide linkage. Mitomycin C (MMC) a versatile drug with antibiotic, antibacterial and antineoplastic properties, was used to prove this concept. The in vitro drug release experiments showed a fast release for the pure MMC (k = 49.59 h⁻ⁿ); however, a significantly lower MMC dissolution rate (k = 2.25, 1.46, and 1.35 h⁻ⁿ) was obtained for the nanoparticles with increased cross-link density (3, 10, 21%). The successful modification and conjugation reactions were confirmed using FTIR and EDX measurements, while the mucoadhesive properties of the self-assembled particles synthesized in a simple one-pot reaction were proved by rheological measurement. The prepared biocompatible polymeric prodrugs are very promising and applicable as a drug delivery system (DDS) and useful in the area of cancer treatment.

Background/Objectives: Bacteriophage therapy represents a promising strategy to combat multidrug-resistant pathogens, such as Escherichia coli. In this study, we explored the effects of a bacteriophage infection on an Extended Spectrum Beta-Lactamase (ESBL) positive E. coli isolate. Methods: We used next generation sequencing, proteomics and phenotypic screens to investigate the effect of bacteriophage infections on E. coli metabolism and resistance phenotypes. Results: The bacteriophage infection led to notable alterations in colony morphology, indicating profound changes in bacterial metabolism. Proteomic analysis revealed significant shifts in protein expression, with 65 proteins upregulated and 246 downregulated post-infection. The downregulated proteins were involved in various metabolic pathways, including nucleic acid, protein and lipid metabolism, and iron acquisition. Bacteriophage treatment also led to increased bacterial membrane permeability. Altogether, these alterations in bacterial metabolism and membrane permeability may lead to a general reduction in antibiotic resistance. Indeed, the bacteriophage-infected E. coli exhibited increased sensitivity to various classes of antibiotics, including beta-lactams, fluoroquinolones, trimethoprim-sulfamethoxazole, and aminoglycosides. Conclusions: Our findings highlight the potential of bacteriophage therapy as an adjunct to existing antibiotics, enhancing their efficacy against resistant strains.

A two-component injectable hydrogel was suitably prepared for the encapsulation and prolonged release of tilorone which is an antimuscular atrophy drug. The rapid (7–45 s, depending on the polymer concentration) in situ solidifications of the hydrogel were evoked by the evolving Schiff-base bonds between the aldehyde groups of modified PVA (4-formyl benzoate PVA, PVA-CHO, 5.9 mol% functionalization degree) and the amino groups of 3-mercaptopropionate chitosan (CHIT-SH). The successful modification of the initial polymers was confirmed by both FTIR and NMR measurements; moreover, a new peak appeared in the FTIR spectrum of the 10% w/v PVA-CHO/CHIT-SH hydrogel at 1647 cm⁻¹, indicating the formation of a Schiff base (–CH=N–) and confirming the interaction between the NH₂ groups of CHIT–SH and the CHO groups of PVA-CHO for the formation of the dynamic hydrogel. The reaction between the NH₂ and CHO groups of the modified biopolymers resulted in a significant increase in the hydrogel’s viscosity which was more than one thousand times greater (9800 mPa·s) than that of the used polymer solutions, which have a viscosity of only 4.6 and 5.8 mPa·s, respectively. Furthermore, the initial chitosan was modified with mercaptopropionic acid (thiol content = 201.85 ± 12 µmol/g) to increase the mucoadhesive properties of the hydrogel. The thiolated chitosan showed a significant increase (~600 mN/mm) in adhesion to the pig intestinal membrane compared to the initial one (~300 mN/mm). The in vitro release of tilorone from the hydrogel was controlled with the crosslinking density/concentration of the hydrogel; the 10% w/v PVA-CHO/CHIT-SH hydrogel had the slowest releasing (21.7 h^−1/2) rate, while the 2% w/v PVA-CHO/CHIT-SH hydrogel had the fastest releasing rate (34.6 h^−1/2). Due to the characteristics of these hydrogels, their future uses include tissue regeneration scaffolds, wound dressings for skin injuries, and injectable or in situ forming drug delivery systems. Eventually, we hope that the developed hydrogel will be useful in the local treatment of muscle atrophy, such as laryngotracheal atrophy.

In this work, we developed multifunctional hydrogel nanoparticles (NPs) that can encapsulate anticancer drugs and imaging contrast agents as well. Mitomycin C (MMC) and rhodamine B (RB) were selected as models for anticancer drugs and imaging contrasting agents, respectively. Both MMC and RB were linked to the succinated polyvinyl alcohol polymer (PVA-SA). The selected labeled hydrogel NPs ((0.5% RB)-PVA-SA NPs and (1.5% RB)-PVA-SA NPs) improved the RB quantum yield from 29.8% to a minimum of 42.7%. Moreover, they showed higher emission stability compared to free RB when they were repeatedly excited at 554 nm for 2 h. Furthermore, the dye polymeric interactions significantly increased the RB fluorescence lifetime by approximately twofold. All these optical properties pave the way for our labeled hydrogel NPs to be used in imaging-guided therapy. For the labeled MMC-loaded NPs, the MMC-binding efficiency was found to be exceedingly high in all synthesized samples: a minimum of 92% was achieved. In addition, the obtained pH-dependent drug release profiles as well as the cytotoxicity evaluation demonstrated the high potential of releasing MMC under acidic cancerous conditions. Moreover, the in vitro cellular uptake experiment confirmed the accumulation of MMC NPs throughout the cytoplasm.