Carlotta Pontremoli1, Isabel Izquierdo-Barba2, Giorgia Montalbano3, María Vallet-Regí4, Chiara Vitale-Brovarone5, Sonia Fiorilli6. 1. Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, Italy. Electronic address: carlotta.pontremoli@polito.it. 2. Departamento de Química en Ciencias Farmacéuticas, Unidad de Química Inorgánica y Bioinorgánica, Universidad Complutense de Madrid. Instituto de Investigación Sanitaria Hospital 12 de Octubre i+12. Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, Av. Monforte de Lemos, 3-5, 28029 Madrid, Spain. Electronic address: ibarba@ucm.es. 3. Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, Italy. Electronic address: giorgia.montalbano@polito.it. 4. Departamento de Química en Ciencias Farmacéuticas, Unidad de Química Inorgánica y Bioinorgánica, Universidad Complutense de Madrid. Instituto de Investigación Sanitaria Hospital 12 de Octubre i+12. Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, Av. Monforte de Lemos, 3-5, 28029 Madrid, Spain. Electronic address: vallet@ucm.es. 5. Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, Italy. Electronic address: chiara.vitale@polito.it. 6. Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, Italy. Electronic address: sonia.fiorilli@polito.it.
Abstract
HYPOTHESIS: The treatment of bone fractures still represents a challenging clinical issue when complications due to impaired bone remodelling (i.e. osteoporosis) or infections occur. These clinical needs still require a radical improvement of the existing therapeutic approach through the design of advanced biomaterials combining the ability to promote bone regeneration with anti-adhesive properties able to minimise unspecific biomolecules adsorption and bacterial adhesion. Strontium-containing mesoporous bioactive glasses (Sr-MBG), which are able to exert a pro-osteogenic effect by releasing Sr2+ ions, have been successfully functionalised to provide mixed-charge (NH3⊕/COO⊝) surface groups with anti-adhesive abilities. EXPERIMENTS: Sr-MBG have been post-synthesis modified by co-grafting hydrolysable short chain silanes containing amino (aminopropylsilanetriol) and carboxylate (carboxyethylsilanetriol) moieties to achieve a zwitterionic zero-charge surface. The final system was then characterised in terms of textural-structural properties, bioactivity, cytotoxicity, pro-osteogenic and anti-adhesive capabilities. FINDINGS: After zwitterionization the in vitro bioactivity was maintained, as well as the ability to release Sr2+ ions which are capable of inducing a mineralization process. Irrespective of their size, Sr-MBG particles did not exhibit any cytotoxicity in pre-osteoblastic MC3T3-E1 up to the concentration of 75 µg/mL. Finally, the zwitterionic Sr-MBGs showed a significant reduction of serum protein adhesion with respect to the pristine ones. These results open promising future expectations in the design of nanosystems which combine pro-osteogenic and anti-adhesive properties.
HYPOTHESIS: The treatment of bone fractures still represents a challenging clinical issue when complications due to impaired bone remodelling (i.e. osteoporosis) or infections occur. These clinical needs still require a radical improvement of the existing therapeutic approach through the design of advanced biomaterials combining the ability to promote bone regeneration with anti-adhesive properties able to minimise unspecific biomolecules adsorption and bacterial adhesion. Strontium-containing mesoporous bioactive glasses (Sr-MBG), which are able to exert a pro-osteogenic effect by releasing Sr2+ ions, have been successfully functionalised to provide mixed-charge (NH3⊕/COO⊝) surface groups with anti-adhesive abilities. EXPERIMENTS: Sr-MBG have been post-synthesis modified by co-grafting hydrolysable short chain silanes containing amino (aminopropylsilanetriol) and carboxylate (carboxyethylsilanetriol) moieties to achieve a zwitterionic zero-charge surface. The final system was then characterised in terms of textural-structural properties, bioactivity, cytotoxicity, pro-osteogenic and anti-adhesive capabilities. FINDINGS: After zwitterionization the in vitro bioactivity was maintained, as well as the ability to release Sr2+ ions which are capable of inducing a mineralization process. Irrespective of their size, Sr-MBG particles did not exhibit any cytotoxicity in pre-osteoblastic MC3T3-E1 up to the concentration of 75 µg/mL. Finally, the zwitterionic Sr-MBGs showed a significant reduction of serum protein adhesion with respect to the pristine ones. These results open promising future expectations in the design of nanosystems which combine pro-osteogenic and anti-adhesive properties.
Authors: Taimoor H Qazi; Shahzad Hafeez; Jochen Schmidt; Georg N Duda; Aldo R Boccaccini; Evi Lippens Journal: J Biomed Mater Res A Date: 2017-07-06 Impact factor: 4.396