Development of Silver Nanoparticles/Gelatin Thermoresponsive Nanocomposites: Characterization and Antimicrobial Activity.

Background: Skin and soft tissue infections involve microbial invasion of the skin and underlying soft tissues. To overcome this problem, nanocomposites were obtained using gelatin as a biopolymer scaffold and silver nanoparticles as a wide spectrum antimicrobial agent. Water and glycerol have been used as solvents for the gelatin hydrogel synthesis. This mixture led to a stable and homogeneous biomaterial with improved mechanical properties.

Methods: Silver nanoparticles were characterized using SEM, EDS and TEM. Moreover, the AgNp/gelatin nanocomposite obtained using these nanoparticles was characterized using SEM and FTIR. Moreover, mechanical and swelling properties were studied.

Results: The storage modulus was 3000 Pa for gelatin hydrogels and reached 5800 Pa for AgNp/gelatin nanocomposite. Silver nanoparticles have been studied as an alternative to antibiotics. Importantly, the rate of silver release was modulated as a function of the temperature of the nanocomposite. Thus, the silver release from the nanocomposites at 24 °C and 38 °C was analyzed by atomic absorption spectroscopy. The silver release reached 25% after 24 h at 24 °C, while a 75% release was achieved at 38°C in the same period, showing the material thermoresponsive behavior. AgNp/gelatin nanocomposite showed a deleterious effect over 99.99% of Pseudomonas aeruginosa and Staphylococcus aureus, leading to a material with antimicrobial properties.

Conclusion: AgNp/gelatin nanocomposite with improved mechanical properties and silver nanoparticles as a source of silver ions has been synthesized. The properties of the nanocomposite with controlled silver delivery result in a more efficient topical pharmaceutical form for wound healing applications.