Degradable Nanohydroxyapatite-Reinforced Superglue for Rapid Bone Fixation and Promoted Osteogenesis

Bone glue with robust adhesion is crucial for treating complicated bone fractures, but it remains a formidable challenge to develop a “true” bone glue with high adhesion strength, degradability, bioactivity, and satisfactory operation time in clinical scenarios. Herein, inspired by the hydroxyapatite and collagen matrix composition of natural bone, we constructed a nanohydroxyapatite (nHAP) reinforced osteogenic backbone-degradable superglue (O-BDSG) by in situ radical ring-opening polymerization. nHAP significantly enhances adhesive cohesion by synergistically acting as noncovalent connectors between polymer chains and increasing the molecular weight of the polymer matrix. Moreover, nHAP endows the glue with bioactivity to promote osteogenesis. The as-prepared glue presented a 9.79 MPa flexural adhesion strength for bone, 4.7 times that without nHAP, and significantly surpassed commercial cyanoacrylate (0.64 MPa). O-BDSG exhibited degradability with 51% mass loss after 6 months of implantation. In vivo critical defect and tibia fracture models demonstrated the promoted osteogenesis of the O-BDSG, with a regenerated bone volume of 75% and mechanical function restoration to 94% of the native tibia after 8 weeks. The glue can be flexibly adapted to clinical scenarios with a curing time window of about 3 min. This work shows promising prospects for clinical application in orthopedic surgery and may inspire the design and development of bone adhesives

Degradable Nanohydroxyapatite-Reinforced Superglue for Rapid Bone Fixation and Promoted Osteogenesis

Bone glue with robust adhesion is crucial for treating complicated bone fractures, but it remains a formidable challenge to develop a “true” bone glue with high adhesion strength, degradability, bioactivity, and satisfactory operation time in clinical scenarios. Herein, inspired by the hydroxyapatite and collagen matrix composition of natural bone, we constructed a nanohydroxyapatite (nHAP) reinforced osteogenic backbone-degradable superglue (O-BDSG) by in situ radical ring-opening polymerization. nHAP significantly enhances adhesive cohesion by synergistically acting as noncovalent connectors between polymer chains and increasing the molecular weight of the polymer matrix. Moreover, nHAP endows the glue with bioactivity to promote osteogenesis. The as-prepared glue presented a 9.79 MPa flexural adhesion strength for bone, 4.7 times that without nHAP, and significantly surpassed commercial cyanoacrylate (0.64 MPa). O-BDSG exhibited degradability with 51% mass loss after 6 months of implantation. In vivo critical defect and tibia fracture models demonstrated the promoted osteogenesis of the O-BDSG, with a regenerated bone volume of 75% and mechanical function restoration to 94% of the native tibia after 8 weeks. The glue can be flexibly adapted to clinical scenarios with a curing time window of about 3 min. This work shows promising prospects for clinical application in orthopedic surgery and may inspire the design and development of bone adhesives

Media 2: Label-free imaging of zebrafish larvae in vivo by photoacoustic microscopy

Originally published in Biomedical Optics Express on 01 February 2012 (boe-3-2-360

RGDC Functionalized Titanium Dioxide Nanoparticles Induce Less Damage to Plasmid DNA but Higher Cytotoxicity to HeLa Cells

In this paper, nano-TiO₂ was functionalized by different methods, and its genotoxicity and cytotoxicity were studied in detail. The genotoxicity of nano-TiO₂ was evaluated by observing its interactions with pUC19 plasmid DNA at a single molecule level using atomic force microscopy. The results show that with the assistance of UVA radiation, RGDC functionalized nano-TiO₂ induced less damage to plasmid DNA than unmodified ones. The HeLa cell-specific PDT effect was investigated by cytotoxicity assay correspondingly. RGDC-functionalized nano-TiO₂ shows the highest killing effect to HeLa cells with the assistance of UVA radiation. The reasons that cause the contradiction between genotoxicity and cytotoxicity were analyzed, and the molecular mechanisms of the PDT effects were discussed. The results show that the genotoxicity of nano-TiO₂ to plasmid DNA and its cytotoxicity to HeLa cells are related but also different. The RGDC functionalization is an effective method to increase the cytotoxicity of nano-TiO₂

Media 1: Label-free imaging of zebrafish larvae in vivo by photoacoustic microscopy

Originally published in Biomedical Optics Express on 01 February 2012 (boe-3-2-360

Synergistic Effects of the Ni₃B Cocatalyst and N Vacancy on g‑C₃N₄ for Effectively Enhanced Photocatalytic N₂ Fixation

The photocatalytic fixation of N2 is a promising technology for sustainable production of ammonia, while the unsatisfactory efficiency resulting from the low electron-transfer rate, narrow light absorption range, and limited active sites of the photocatalyst seriously hinder its application. Herein, we designed a noble metal-free Schottky junction photocatalyst constructed by g-C3N4 nanosheets with N vacancies (VN-CN) and metallic Ni3B nanoparticles (Ni3B/VN-CN) for N2 reduction to ammonia. The ammonia yield rate over the optimized Ni3B/VN-CN is 7.68 mM g–1 h–1, which is 6.7 times higher than that of pristine CN (1.15 mM g–1 h–1). The superior photocatalytic N2 fixation performance of Ni3B/VN-CN can be attributed not only to the formation of Schottky junctions between Ni3B and VN-CN, which facilitates the migration and separation of photogenerated electrons, but also to the incorporation of VN into g-C3N4, which enhances visible light absorption and improves electrical conductivity. More importantly, Ni3B nanoparticles can act as the cocatalyst, which provide more active sites for the adsorption and activation of N2, thereby improving the N2 reduction activity. This work provides an effective strategy of designing noble metal-free-based cocatalyst photocatalyst for sustainable and economic N2 fixation

Systematic Characterization of the Metabolism of Acetoin and Its Derivative Ligustrazine in Bacillus subtilis under Micro-Oxygen Conditions

Bacillus subtilis is an important microorganism for brewing of Chinese Baijiu, which contributes to the formation of flavor chemicals including acetoin and its derivative ligustrazine. The first stage of Baijiu brewing process is under micro-oxygen conditions; however, there are few studies about B. subtilis metabolism under these conditions. Effects of various factors on acetoin and ligustrazine metabolism were investigated under these conditions, including key genes and fermentation conditions. Mutation of <i>bdhA</i> (encoding acetoin reductase) or overexpression of <i>glcU</i> (encoding glucose uptake protein) increased acetoin concentration. Addition of Vigna angularis powder to the culture medium also promoted acetoin production. Optimal culture conditions for ligustrazine synthesis were pH 6.0 and 42 °C. Ammonium phosphate was shown to promote ligustrazine synthesis in situ. This is the first report of acetoin and ligustrazine metabolism in B. subtilis under micro-oxygen conditions, which will ultimately promote the application of B. subtilis for maintaining Baijiu quality

SDS-PAGE (A) and Western blotting (B) analysis of HMW-GSs from <i>Ag. intermedium</i> and bacterial expression products.

<p>Lane 1 is HMW-GSs from common wheat variety Chinese Spring, the four expressed HMW-GSs are noted on left; Lane 2 is native HMW-GS from the seed of <i>Ag. intermedium</i> same as the lane 2 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0087477#pone-0087477-g001" target="_blank">Figure 1</a>, the seven expressed HMW-GSs are marked with triangles; Lane 3, 5, 7, 9, 11, 13 and 15 are total cell proteins from IPTG induced <i>E. coli</i> containing pET-<i>Glu-1Ai1</i>, pET-<i>Glu-1Ai2</i>, pET-<i>Glu-1Ai3</i>, pET-<i>Glu-1Ai4</i>, pET-<i>Glu-1Ai5</i> pET-<i>Glu-1Ai6</i> and pET-<i>Glu-1Ai7</i>, respectively, whereas the dextral lanes for each of them shows the total cell proteins from their bacterial cells without induction of IPTG. The seven expressed target proteins in <i>E. coli</i>, which were detected by SDS-PAGE (marked with arrows in A) and were confirmed by Western blotting (lanes 3, 5, 7, 9, 11, 13 and 15 in B), share comparable electrophoretic mobility with those native HMW-GSs from <i>Ag. intermedium</i> (lane 2).</p

MALDI-TOF-MS analysis of peptide mass fingerprint of native 1Aiy1 subunit.

<p>Peptide mass is available at <a href="http://www.expasy.org/tools/peptide-mass.html" target="_blank">http://www.expasy.org/tools/peptide-mass.html</a>.</p

SDS-PAGE (A) and Western blotting (B) analysis of HMW-GSs of <i>Ag. intermedium</i>.

<p>Lane 1 shows the named HMW-GSs from common wheat variety Chinese Spring as a control. Lanes 2∼7 show the HMW-GSs from six representative seeds of the <i>Ag. intermedium</i> line used in this study. The seven expressed HMW-GSs with distinct electrophoretic mobility comparing with Chinese Spring were detected by SDS-PAGE (A) and were confirmed using Western blotting experiment with polyclonal antibody specific for HMW-GSs (B). Among the seven HMW-GSs from <i>Ag. intermedium</i>, three subunits (marked with solid triangles in lane 2 of B) share comparable electrophoretic mobility with Chinese Spring, the other four subunits (marked with hollow triangles in lane 2 of B) moved faster than those HMW-GSs from Chinese Spring.</p