Ultrasmall silver nanoparticles loaded in alginate–hyaluronic acid hybrid hydrogels for treating infected wounds
Creators: name: Catanzano, Ovidio
name: D’Esposito, Vittoria
name: Pulcrano, Giovanna
name: Maiolino, Sara
name: Ambrosio, Maria Rosaria
name: Esposito, Matilde
name: Miro, Agnese
name: Ungaro, Francesca
name: Formisano, Pietro
name: Catania, Maria Rosaria
name: Quaglia, Fabiana
Publisher: name: Taylor & Francis
Year: 2017
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: FOS: Biological sciences
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: FOS: Chemical sciences
subject: Immunology
subject: FOS: Clinical medicine
subject: FOS: Clinical medicine
subject: 69999 Biological Sciences not elsewhere classified
subject: Cancer
subject: 110309 Infectious Diseases
subject: FOS: Health sciences
subject: FOS: Health sciences

description: Nowadays, silver nanoparticles are in the limelight to control infection during wound healing process, and a vast variety of antimicrobial dressings based on colloidal silver have been marketed to fight wound invasion of pathogen bacteria, which represents one of the main adverse effects limiting the repair process. Here we propose a biofunctional hydrogel based on alginate (ALG) and hyaluronic acid (HA) embedding ultrasmall silver nanoparticles (usSN, &lt;1 nm) as antimicrobial component. The hydrogels were fabricated in different size by a straightforward internal gelation method using CaCO<sub>3</sub> and glucono-δ-lactone. To follow usSN release from the hydrogels in aqueous media, catalytic activity of usSN-loaded hydrogels was evaluated. Results suggested that catalytic activity was low in intact hydrogels and high when hydrogels dissolved, which suggests that usSN firmly interact with polymer chains and are available in the medium depending on the extent of hydrogel degradation. HA-containing hydrogels showed faster dissolution in simulated physiological conditions and higher antibiofouling properties as compared to hydrogels made only of ALG. Free usSN were not toxic toward human mesenchymal stem cells (Ad-MSCs), previously isolated from subcutaneous adipose tissue biopsies, up to 50 µg/mL. At this concentration, viability of Ad-MSCs was unaffected whereas their motility was significantly higher as compared to control (<i>p</i>&lt;0.01) for both free usSN and hydrogel integrating. Antimicrobial activity on clinical isolates of both Gram-positive and Gram-negative bacteria demonstrated that usSN at 50 µg/mL were able to kill all the bacteria tested after 24 and 48 h of contact time. In the case of hydrogels, a matrix effect was found and bacterial killing was significant only at 24 h and dependent on bacterial strain, being Gram-negative bacteria more susceptible. These results clearly indicate that usSN interaction with polymer network and exposure time can strongly affect usSN antimicrobial profile in the hydrogel and, in turn, timing of hydrogel change at injured site in a clinical setting. On the whole, ALG/HA hydrogels integrating usSN can be considered a suitable option to fabricate biofunctional dressings for hospitalized patients and worth of further <i>in vivo</i> investigation.