Balancing Bacteria–Osteoblast Competition through Selective Physical Puncture and Biofunctionalization of ZnO/Polydopamine/Arginine-Glycine-Aspartic Acid-Cysteine Nanorods

Abstract

Bacterial infection and lack of bone tissue integration are two major concerns of orthopedic implants. In addition, osteoinductivity often decreases and toxicity may arise when antibacterial agents are introduced to increase the antibacterial ability. Here hybrid ZnO/polydopamine (PDA)/arginine-glycine-aspartic acid-cysteine (RGDC) nanorod (NR) arrays are designed and prepared on titanium (Ti) implants to not only enhance the osteoinductivity but also effectively kill bacteria simultaneously, which are ascribed to the selective physical puncture and the biofunctionalization of ZnO/PDA/RGDC nanorods during the competition between bacteria and osteoblasts. That is, owing to the much larger size of osteoblasts than bacteria, the hybrid NRs can puncture bacteria but not damage osteoblasts. Meanwhile, the cytocompatibility can be enhanced through the suppression of both reactive oxygen species and higher Zn concentration by the covering of PDA and RGDC. The in vitro results confirm the selective puncture of the bacterial membrane and the better osteoinductivity. In vivo tests also show much higher antibacterial efficacy of the hybrid NRs with far less amounts of lobulated neutrophils and adherent bacteria in the surrounding tissues. In addition, the hybrid NRs also accelerate formation of new bone tissues (20.1% higher than pure Ti) and osteointegration between implants and newly formed tissues (32.0% higher than pure Ti) even in the presence of injected bacteria. This work provides a surface strategy for designing implants with desirable ability of osseointegration and infection prevention simultaneously, which will exhibit tremendous clinical potential in orthopedic and dental applications.

Rapid and Superior Bacteria Killing of Carbon Quantum Dots/ZnO Decorated Injectable Folic Acid‐Conjugated PDA Hydrogel through Dual‐Light Triggered ROS and Membrane Permeability

“…Furthermore, the peak at 530 cm −1 in the DFT‐hydrogel spectrum is assigned to the metal‐oxygen bond, which is considered the key factor in gelation . The signal at 1630 cm −1 appears in the spectra of both PDA and DFT‐hydrogel, indicating the existence of PDA in the DFT‐hydrogel . The similar peak located at 360 nm in the UV–vis spectra shown in Figure C further confirms the successful combination of FA and PDA …”

“…Figure B shows the high‐resolution C 1s spectra of C/ZnO‐PDA. The C 1s peaks can be divided into four peaks at 286.3, 285.4, 284.6, and 284.1 eV, which are assigned to CO, CN, CC, and CC, respectively, further proving the association between C/ZnO and PDA. In Figure C, the DFT‐C/ZnO‐hydrogel shows diffraction peaks arising from the (100), (002), (101), and (110) planes, matching the C/ZnO structure (Figure B) and thus proving the successful loading of C/ZnO into the hydrogel.…”

“…In Figure A, the peaks in X‐ray photoelectron spectroscopy (XPS) survey spectra located at 284.6, 531.1, and 1021.3 eV are attributed to C 1s, O 1s, and Zn 2p, respectively . After being coated by PDA, C/ZnO‐PDA exhibits a new peak at 399.3 eV that is attributed to N 1s, proving the association of C/ZnO and PDA .…”

“…As shown in the X‐ray diffraction (XRD) patterns (Figure B), the observed peaks are located at 31.88°, 34.41°, 36.26°, 47.52°, and 56.62°, corresponding to different crystal planes of ZnO ((100), (002), (101), (102), and (110), respectively), which is in good agreement with the peaks of hexagonal phase ZnO (JCPDS No. 79‐0206) . In addition to the characteristic ZnO peaks, there is a graphitic (002) peak near 26° (the enlarged XRD patterns between 20° and 30° are shown in the inset of Figure B) .…”

Light‐Activated Rapid Disinfection by Accelerated Charge Transfer in Red Phosphorus/ZnO Heterointerface

“…Pathogenic microorganisms related to infectious diseases are the second largest murderer of death worldwide with 17 million annual victims . There is an increasing demand to explore innovative disinfection techniques in response to the prevalence of pathogenic microorganisms and bacterial outbreaks originating from medical treatment, contaminated water reservoirs, human contact, and so on . Specifically, medical device‐associated infections contribute to a great part of hospital‐acquired infections, which make up 25.6% of all health‐care‐associated infections in the USA .…”