Antibacterial and osteogenic stem cell differentiation properties of photoinduced TiO₂ nanoparticle-decorated TiO₂ nanotubes
Authors: Hongyi Li
Na Wang
Su Chen
Yiran Liu
Yuanping Ma
Zhenting Zhang
Jinshu Wang
Thomas J Webster
Penglei Su
Wenwen Liu
Journal: Nanomedicine (2015)
Discipline: CLINICAL MEDICINE
Keywords: TiO2 nanoparticles; antibacterial effect; photocatalysis; stem cells; titania nanotubes.
Affiliations: Laboratory of Biomaterials & Biomechanics, Beijing Key Laboratory of Tooth Regeneration & Function Reconstruction, School of Stomatology, Capital Medical University, Tian Tan Xi Li No. 4, Beijing 100050, China.

Abstract:  Aim: To improve the antibacterial and mammalian cell compatibility properties of titania nanotubes (TNTs) anodized into titanium (Ti). Materials &amp; methods: 3-8-nm TiO2 nanoparticles were decorated on the surface and inside TNT (TNT-TiO2) through a hydrothermal method. After UV light treatment, two types of oral bacteria and stem cells were cultured on the samples to determine antibacterial and compatibility properties. Results: TiO2 nanoparticles increased the surface area and photocatalysis of TNTs. Based on the photocatalysis effect and prolonged photo-induced wettability, the numbers of Streptococcus mutans and Porphyromonas gingivalis were lower on the surface of TNT-TiO2 than pure Ti and TNTs after the first 7 days. Specifically, for S. mutans, the glycosytransferase (gtf) genes were downregulated 0.1-0.2-fold on TNT-TiO2. Due to the different topography and high surface energy of TNT-TiO2, stem cells also showed improved osteogenic functions on TNT-TiO2. Conclusion: In this study, we demonstrated for the first time improved antibacterial properties and, at the same time, greater stem cell osteogenic capacity when decorating TNTs with nanosized TiO2 particles, which may significantly improve orthopedic and dental implant efficacy. 

Retracted: No

PubPeer comments:
 Concern about Figure 6, panels D-F. Some features appear to be visible multiple times within the same panel or between panels. The legend reads: *Porphyromonas gingivalis on samples: (D) Ti, (E) TNTs and (F) TNT-TiO2.*, so the panels are expected to look different from each other. ![file] , 
 And a Twitter user pointed out a possible duplication in Figure 6, panel C. Marked here in aqua blue. ![file] , 
 June 2020 Corrigendum found here: https: www.futuremedicine.com doi full 10.2217 nnm.14.183.c1 - which costs $67 to read. The journal never notified me of what they did with my reported concern, and I do not think I should have to spend that much money to find out. ![file] So here is the free version of this corrigendum. A corrigendum is, in my professional opinion - not a good outcome for the problems detected in Figure 6. ![file] , 
 Update May 11 2021: The journal publisher has now made the Corrigendum free to read, which is great news. I thank the publisher for taking this step, and I hope they will look in more details to see if a correction should have been the right action here. , 
 https: www.futuremedicine.com journals nnm editors ![file] , 
 **Retraction** Published Online: 18 Jun 2021 Liu W, Su P, Chen S, Wang N, Wang J, Liu Y, Ma Y, Li H, Zhang Z, Webster TJ. Antibacterial and osteogenic stem cell differentiation properties of photoinduced TiO2 nanoparticle-decorated TiO2 nanotubes. Nanomedicine (Lond.) 10(5), 713u2013723 (2015). The authors previously highlighted an issue relating to Figure 6 (Fluorescence images showing the viability of the Streptococcus mutans on samples) in this paper and a corrigendum was published to remove it. It was determined that the conclusions of the study were still valid without this figure. However, it has since been identified that parts of the figure in question contained manipulated images. The authors have reconsidered the completeness of the paper and have decided to retract it. The authors and editors of Nanomedicine regret any negative consequences this publication might have caused in the scientific and medical communities. ,