Laser-Assisted Nanotexturing and Silver Immobilization on Titanium Implant Surfaces to Enhance Bone Cell Mineralization and Antimicrobial Properties

Abstract

Despite the great advancement and wide use of titanium (Ti) and Ti-based alloys in different orthopedic implants, device-related infections remain the major complication in modern orthopedic and trauma surgery. Most of these infections are often caused by both poor antibacterial and osteoinductive properties of the implant surface. Here, we have demonstrated a facile two-step laser nanotexturing and immobilization of silver onto the titanium implants to improve both cellular integration and antibacterial properties of Ti surfaces. The required threshold laser processing power for effective nanotexturing and osseointegration was systematically determined by the level of osteoblast cells mineralized on the laser nanotextured Ti (LN−Ti) surfaces using a neodymium-doped yttrium aluminum garnet laser (Nd:YAG, wavelength of 1.06 μm). Laser processing powers above 24 W resulted in the formation of hierarchical nanoporous structures (average pore 190 nm) on the Ti surface with a 2.5-fold increase in osseointegration as compared to the pristine Ti surface. Immobilization of silver nanoparticles onto the LN−Ti surface was conducted by dip coating in an aqueous silver ionic solution and subsequently converted to silver nanoparticles (AgNPs) by using a low power laser-assisted photocatalytic reduction process. Structural and surface morphology analysis via XRD and SEM revealed a uniform distribution of Ag and the formation of an AgTi-alloy interface on the Ti surface. The antibacterial efficacy of the LN−Ti with laser immobilized silver (LN− Ti/LI−Ag) was tested against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The LN− Ti/LI−Ag surface was observed to have efficient and stable antimicrobial properties for over 6 days. In addition, it was found that the LN−Ti/LI−Ag maintained a cytocompatibility and bone cell mineralization property similar to the LN−Ti surface. The differential toxicity of the LN−Ti/LI−Ag between bacterial and cellular species qualifies this approach as a promising candidate for novel rapid surface modification of biomedical metal implants.

Antibacterial and Osteogenic Properties of Ag Nanoparticles and Ag/TiO2 Nanostructures Prepared by Atomic Layer Deposition

“…On the one hand, the Ag-related production of ROS may have a negative effect on the viability, proliferation, and differentiation of preosteoblast cells. On the other hand, the rate of osseointegration of the implant significantly increases in the presence of an antibacterial effect simultaneously with the absence of preosteoblasts’ cytotoxicity, due to the “race for surface” effect [ 36 ]. Namely, preosteoblasts win the competition with bacteria to attach to the implant surface and proliferate.…”

Organ-on-a-Chip Platform with an Integrated Screen-Printed Electrode Array for Real-Time Monitoring Trans-Epithelial Barrier and Bubble Formation

“…The PDMS layer was prepared by mixing the 10:1 ratio of the PDMS crosslinker and the curing agent, followed by oven curing at 85 °C for 3 h. Next, the PDMS film was laser cut (PLS6MW, Universal Laser Systems Inc., Scottsdale, AZ, λ = 10.6 μm) into the desired channel dimensions required in the platform. 41 Two sets of Ag/AgCl electrodes for bubble and TEER detection were screen printed (MPS TF-100, Micro Printing Systems) on the PET films and were oven annealed at 120 °C for 15 min (Figure 2a and the Supporting information, Figure S1). The paired linear electrode array with the active sensing area of 5 × 1 mm 2 was used for the detection, and the single-paired 15 × 1 mm 2 electrodes were used for TEER measurements.…”

“…The device was fabricated by assembling a PDMS film (thickness 1.5 mm) between two layers of PET film with printed electrodes. The PDMS layer was prepared by mixing the 10:1 ratio of the PDMS crosslinker and the curing agent, followed by oven curing at 85 °C for 3 h. Next, the PDMS film was laser cut (PLS6MW, Universal Laser Systems Inc., Scottsdale, AZ, λ = 10.6 μm) into the desired channel dimensions required in the platform . Two sets of Ag/AgCl electrodes for bubble and TEER detection were screen printed (MPS TF-100, Micro Printing Systems) on the PET films and were oven annealed at 120 °C for 15 min (Figure a and the Supporting information, Figure S1).…”

Metal-Phenolic Networks Assembled on TiO2 Nanospikes for Antimicrobial Peptide Deposition and Osteoconductivity Enhancement in Orthopedic Applications

“…Titanium (Ti) and its alloys account for a significantly large proportion in orthopedic implant applications due to their superior mechanical properties, corrosion resistance, and biocompatibility. − However, the surfaces of Ti and its alloys are prone to be colonized by planktonic bacteria and aggregates of these microorganisms subsequently form biofilm, causing increasing cases of biomaterial-associated infections (BAIs) during or after the implantation. , Additionally, the inherent bio-inertness of Ti inevitably leads to the shortage of osteoconductive activity at the implant interface and impedes the long-term structural fixation. , It was estimated that bacterial infection is responsible for around 20% operation failure, while aseptic loosening of implants accounts for nearly 18% operation failure. , The frequent occurrence of infection and loosening of implants increases the risk of secondary surgery, leaving patients in physical and psychological torment as well as burdening the healthcare system. , To overcome these challenges, it is urgently needed to develop coping strategies to endow them with effective antibacterial capabilities and osteoconductive activities. , …”