In this study, a hydrogel material based on porcine gelatin and sodium alginate was synthesized for use as a dressing for chronic wound treatment. The hydrogels were covalently cross-linked using polyethylene glycol diglycidyl ether (PEGDE 500), and the interaction between the components was confirmed via FTIR. The properties of the resulting hydrogels were examined, including gel-fraction volume, swelling degree in different media, mechanical properties, pore size, cytotoxicity, and the ability to absorb and release analgesics (lidocaine, novocaine, sodium diclofenac). The hydrogel’s resistance to enzymatic action by protease was enhanced both through chemical cross-linking and physical interactions between gelatin and alginate. The absorption capacity of the hydrogels, reaching 90 g per dm² of the hydrogel dressing, indicates their potential for absorbing wound exudates. It was demonstrated that the antiseptic (chlorhexidine) contained in the structured gelatin–alginate hydrogels can be released into an infected substrate, resulting in a significant inhibition of pathogenic microorganisms (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Aspergillus niger). These results clearly demonstrate that the obtained hydrogel materials can serve as non-traumatic dressings for the treatment of chronic and/or infected wounds.

Alginate hydrogels are attractive for biomedical applications and drug delivery due to their biocompatibility and biodegradability. However, calcium-crosslinked alginates often exhibit only moderate absorption properties compared with synthetic hydrogels. This study examined how the form of calcium ion delivery affects the mechanical, swelling, and morphological characteristics of calcium-crosslinked alginate hydrogels. We prepared four alginate hydrogel samples in which Ca²⁺ was introduced on different polyacrylate polymer carriers, and a reference hydrogel crosslinked with calcium citrate. All samples were characterized by equilibrium swelling, gel fraction determination, and rheological frequency-sweep measurements. Also, the average mesh size was estimated using two independent theoretical approaches. Hydrogels prepared with calcium salt of polyacrylic acid (PAA) exhibited higher mechanical strength and higher water swelling than the citrate-crosslinked reference. Calculated mean mesh sizes for the citrate system ranged from 58 to 221 nm, whereas high-molecular-weight crosslinked systems showed a broader distribution (68–708 nm). These results demonstrate that the form of Ca²⁺ introduction significantly influences network architecture and functional properties and indicates that tuning the carrier form of calcium provides a practical route to design swelling, mesh size, and mechanical behavior of alginate-based hydrogels for specific biomedical or delivery applications.

The work presents the results of research on the formation of a hydrogel polymer matrix during the gelatin crosslinking with a dioxirane derivative of poly(ethylene glycol) and experiments on studying their properties. The crosslinking process of type A gelatin using poly(ethylene glycol) diglycidyl ether (PEGDE 500) was optimized by changing the gelatin: PEGDE ratio without using any other factors. The properties of the obtained hydrogels were studied, in particular the gel fraction amount, the degree of swelling in different media, mechanical properties, pore size, cytotoxicity, the ability to absorb and release antiseptic drugs, and bactericidal properties of hydrogel samples filled with an antiseptic agent (chlorhexidine). The crosslinking reaction has been found to be the most efficient at gelatin: PEGDE 500 ratio ranging from 1:3 to 1:5. In this case, the formation of highly elastic hydrogels with maximum fraction amount and high mechanical properties was observed (the samples were not destroyed under compression). Moreover, only within this ratio range, the obtained hydrogels retained their shape when heated to 40 °C. The pore sizes of the swollen hydrogel clearly depend on the crosslinker content. The high values of the degree of swelling in the exudate-simulating fluid in combination with mechanical strength allow the development of wound dressings based on hydrogels of the developed composition. Crosslinking of gelatin with PEGDE 500 allows to obtain gelatin-based hydrogels in a controlled manner which does not require subsequent purification steps. The resulting material does not exhibit cytotoxicity during in vitro studies on living cells. The hydrogel filled with an antiseptic drug is capable of releasing it by 50% within the first day into the medium of saline and exudate-simulating fluid. The antimicrobial properties of the hydrogel containing chlorhexidine are confirmed by the effective inhibition of the growth of Escherichia coli and Staphylococcus aureus bacteria.

Prolonged use of antibiotics can cause toxicity in human and animal cells and lead to the development of antibiotic resistance. The development of drug delivery systems for enhanced antibacterial properties of antibiotics could reduce toxic effects and minimize the development of resistance. The aim of this study was to evaluate the effectiveness of oxytetracycline in complexes with new polyphosphate ester-type transporters and to investigate the antimicrobial effect of these complexes on Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus growth in vitro. Two polyphosphate ester-type transporters with different molecular weights were synthesized, and oxytetracycline was attached through the phosphorus groups. To determine the sensitivities of microorganisms, oxytetracycline hydrochloride and oxytetracycline complexes with polyphosphate ester-type transporters (P4 and P6) were added to liquid and solid media with E. coli, P. aeruginosa, and S. aureus in different doses. Oxytetracycline in complex with polyphosphate ester-type transporters at low doses (2.3 to 3.8 μg/disk or μg/mL) in both solid and liquid media inhibits the growth of S. aureus more effectively than oxytetracycline alone. The maximum influence on E. coli growth on solid media is observed at a dose of 8 μg/disk of oxytetracycline in combination with both P4 and P6 polyphosphate ester-type transporters. P. aeruginosa growth under the influence of oxytetracycline in combination with polyphosphate-ester type transporters in a liquid medium depends on the dose of antibiotic and the day of cultivation.