RT Journal Article T1 Impact of the antibiotic-cargo from MSNs on gram-positive and gram-negative bacterial biofilms. A1 Aguilar Colomer, Anna A1 Colilla Nieto, Montserrat A1 Izquierdo Barba, Isabel A1 Jiménez Jiménez, Carla A1 Mahillo, Ignacio A1 Esteban, Jaime A1 Vallet Regí, María Dulce Nombre AB Mesoporous silica nanoparticles (MSNs) are promising drug nanocarriers for infection treatment. Many investigations have focused on evaluating the capacity of MSNs to encapsulate antibiotics and release them in a controlled fashion. However, little attention has been paid to determine the antibiotic doses released from these nanosystems that are effective against biofilm during the entire release time. Herein, we report a systematic and quantitative study of the direct effect of the antibiotic-cargo released from MSNs on Gram-positive and Gram-negative bacterial biofilms. Levofloxacin (LVX), gentamicin (GM) and rifampin (RIF) were separately loaded into pure-silica and amino-modified MSNs. This accounts for the versatility of these nanosystems since they were able to load and release different antibiotic molecules of diverse chemical nature. Biological activity curves of the released antibiotic were determined for both bacterial strains, which allowed to calculate the active doses that are effective against bacterial biofilms. Furthermore, in vitro biocompatibility assays on osteoblast-like cells were carried out at different periods of times. Albeit a slight decrease in cell viability was observed at the very initial stage, due to the initial burst antibiotic release, the biocompatibility of these nanosystems is evidenced since a recovery of cell viability was achieved after 72 h of assay. Biological activity curves for GM released from MSNs exhibited sustained patterns and antibiotic doses in the 2-6 µg/mL range up to 100 h, which were not enough to eradicate biofilm. In the case of LVX and RIF first-order kinetics featuring an initial burst effect followed by a sustained release above the MIC up to 96 h were observed. Such doses reduced by 99.9% bacterial biofilm and remained active up to 72 h with no emergence of bacterial resistance. This pioneering research opens up promising expectations in the design of personalized MSNs-based nanotherapies to treat chronic bone infection. PB Elsevier SN 1387-1811 YR 2020 FD 2020-10-07 LK https://hdl.handle.net/20.500.14352/6624 UL https://hdl.handle.net/20.500.14352/6624 LA eng NO RESEARCHER ID N-4628-2014 (Montse Colilla Nieto)ORCID 0000-0003-1961-4160 (Montse Colilla Nieto)RESEARCHER ID M-9921-2014 (Isabel Izquierdo Barba)ORCID 0000-0002-4139-4646 (Isabel Izquierdo Barba)RESEARCHER ID M-3378-2014 (María Vallet Regí)ORCID 0000-0002-6104-4889 (María Vallet Regí) NO Unión Europea. Horizonte 2020 NO Ministerio de Ciencia e Innovación (MICINN)/FEDER DS Docta Complutense RD 7 may 2024