Bioinspired and Biomimetic AgNPs/Gentamicin-Embedded Silk Fibroin Coatings for Robust Antibacterial and Osteogenetic Applications

Abstract

With the progressively increasing demand for orthopedic Ti implants, the balance between two primary complications restricting implant applications is needed to be solved: the lack of bone tissue integration and biomedical device-associated infections (BAI), where emergence of multiresistance bacteria make it worse. Notably, a combination of silver nanoparticles (AgNPs) and a kind of antibiotic can synergistically inhibit bacterial growth, where a low concentration of AgNPs has been confirmed to promote the proliferation and osteogenesis of osteoblasts. In this work, we built AgNPs/gentamicin (Gen)-embedded silk fibroin (SF)-based biomimetic coatings on orthopedic titanium by a facile dipping-drying circular process and with the assistance of polydopamine (PD). Ag was reduced to AgNPs by SF under ultraviolet (UV) irradiation, and then they were detected by transmission electron microscope (TEM) images and UV-visible (UV-vis) analyses. Intriguingly, the addition of Gen highly improved the reduction efficiency of Ag. The antibacterial efficiency of SF-based coatings was examined by challenging them with pathogenic Staphylococcus aureus (S. aureus) bacteria which produced biofilms, and consequently, we found that low concentration loading, durable release of Ag (28 days), and 10-fold improvement of antibacterial efficiency were achieved for our novel AgNPs- and Gen-embeded silk fibroin coatings. In bacteria and a cells cocultured system, AgNPs/Gen-embedded coatings strongly inhibited adhesion and proliferation of S. aureus, simultaneously improving cell adhesion and growth. To investigate cytocompatibility and osteogenic potential, different coatings were cultured with MC3T3 cells; AgNPs/Gen-embedded coatings showed generally acceptable biocompatibility (cell adhesion, proliferation, and viability) and accelerated osteoblast maturation (alkaline phosphatase production, matrix secretion, and calcification). Expectantly, this novel biofunctional coating will have promising applications in orthopedic and dental titanium implants thanks to its excellently antibacterial, biocompatible, and osteogenic activities.

Preparing and immobilizing antimicrobial osteogenic growth peptide on titanium substrate surface

“…To further accurately investigate the antibacterial effect and observe the morphology changes of bacteria on different surface, SEM measurement was performed after culturing with bacteria for 6 h. 6,39,47 It was found that S. aureus cells which colonized on bare Ti surface [ Fig. 10(A,a)] were smooth, plump, and polymeric.…”

“…It is worth mentioning that antibiotics (e.g., vancomycin, gentamicin, ciprofloxacin—though may induce bacterial antibiotic resistance) are widely used as they can rapidly and effectively against a broad spectrum of bacteria . Ciprofloxacin (CIP), as a representative synthetic antimicrobial agent, is efficaciously against both Gram‐positive and ‐negative strains, including some strains resistant to penicillin, cephalosporins, and aminoglycosides .…”

“…It is worth mentioning that antibiotics (e.g., vancomycin, gentamicin, ciprofloxacin-though may induce bacterial antibiotic resistance) are widely used as they can rapidly and effectively against a broad spectrum of bacteria. 17,[36][37][38][39] Ciprofloxacin (CIP), as a representative synthetic antimicrobial agent, is efficaciously against both Gram-positive and -negative strains, including some strains resistant to penicillin, cephalosporins, and aminoglycosides. [40][41][42][43] Except for the broad spectrum antimicrobial activity, CIP is the least expensive drug in the fluoroquinolone family and is already FDA approved and indicated for bone and joint infections.…”

Effects of Programmed Local Delivery from a Micro/Nano‐Hierarchical Surface on Titanium Implant on Infection Clearance and Osteogenic Induction in an Infected Bone Defect

“…FN acted as a model protein. Quantifiably, a Micro BCA Protein Assay Reagent Kit (Thermo Scientific, USA) was applied to measure absorbance at 570 nm on a Multimode Plate Reader (PerkinElmer, EnSpire, USA) to test the protein adsorption property of AH‐Sr‐AgNPs coating …”

Modification of Electrical Properties of Silver Nanoparticle

“…Silver has also been used in various industries and health fields. Silver is known to have antibacterial properties [13][14][15][16], as a catalyst [17][18][19][20], and it shows stable to the environment [21] and has been utilized as a significant component of water treatment.…”