170215 20260407115449.0 doi 10.3390/gels12030231 sideral 148680 ART-2026-148680 eng Salto-Girón, Carmen Protein-directed nucleation and stabilization of ultrasmall silver nanoparticles within BSA hydrogels 2026 Biocompatible nanocomposite hydrogels are emerging as versatile platforms in nanomedicine, particularly when natural proteins are used as both structural and chemical components. In this work, we report a green, simple, and rapid in situ synthesis of ultrasmall silver nanoparticles (uAgNPs) within a bovine serum albumin (BSA) hydrogel, in which albumin simultaneously acts as the reducing agent and three-dimensional scaffold. The confined reaction environment generated uniformly dispersed Ag nanostructures with diameters in the 4–40 nm range, as confirmed by DLS and TEM. High-resolution TEM revealed clear Face-Centered Cubic (FCC, 111) lattice fringes, demonstrating the crystalline nature of the embedded uAgNPs. Quantitative image analysis showed narrow size distributions and high circularities, consistent with cluster stabilization through protein–metal interactions. Rheological measurements further indicated that the incorporation of uAgNPs enhanced hydrogel stiffness and delayed yielding, reflecting a reinforcement effect mediated by the nanoparticles acting as additional cross-linking points. Moreover, when very small embedded uAgNPs are formed, the presence of emissive silver nanoclusters was found using fluorescence emission spectroscopy. Overall, our results show that BSA hydrogels provide an effective matrix for directing green uAgNP nucleation, ensuring high stability, controlled growth in less than 2 min, and improved mechanical properties. The resulting protein–nanoparticle composite constitutes a promising soft material for imaging, sensing, and other biomedical applications requiring stable, biocompatible nanoscale architectures. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/AEI/CEX2023-001286-S info:eu-repo/grantAgreement/ES/UZ-DGA/T57-23R info:eu-repo/semantics/openAccess by https://creativecommons.org/licenses/by/4.0/deed.es info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion González-García, M. Carmen Mañas-Torres, Mari C. López-López, Modesto T. Álvarez de Cienfuegos, Luis Hueso, José L. Universidad de Zaragoza (orcid)0000-0002-4546-4111 Orte, Angel García-Fernández, Emilio 5005 790 Universidad de Zaragoza Dpto. Ing.Quím.Tecnol.Med.Amb. Área Tecnologi. Medio Ambiente 12, 3 (2026), 231 Gels Gels 2310-2861 Material suplementario https://www.mdpi.com/article/10.3390/gels12030231/s1 1461470 http://zaguan.unizar.es/record/170215/files/texto_completo.pdf Versión publicada 2553283 http://zaguan.unizar.es/record/170215/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:170215 articulos driver 2026-03-26-14:31:52 ARTICLE