Development and antibacterial activities of bacterial cellulose/graphene oxide-CuO nanocomposite films.

The absence of antibacterial activity of bacterial cellulose (BC) restricts its applications in the biomedical field. To introduce antimicrobial properties into BC, we studied the synthesis, structure, and antimicrobial properties of a novel nanocomposite film comprising BC, graphene oxide (GO), and copper-oxide (CuO) nanosheets. The nanocomposite film was synthesized by incorporating GO-CuO nanohybrids into BC matrix through homogenized blending. The CuO nanosheets, with a length range of 50 nm-200 nm and width range of 20 nm-50 nm, which were uniformly grown on the GO along with even distribution of GO-CuO nanohybrids on the surface of the cellulose fibers. The nanocomposites displayed better antibacterial activity against gram-positive than gram-negative bacteria. BC/GO-CuO nanocomposites showed higher antibacterial activity than BC/CuO. We also elucidated the mechanism of antibacterial activity of the nanocomposites. Further, the nanocomposites exhibited biocompatibility towards mice fibroblast cells. The nanocomposites might serve as an excellent source for development of antibacterial materials.

[Clinical study of temperature contrast injection procedure in prevention of bone cement leakage during vertebroplasty].

OBJECTIVE: To observe the effect of temperature contrast injection procedure on prevention and reduction of bone cement leakage in vertebroplasty (PVP). METHODS: The clinical data of 42 patients(48 vertebral bodies) with osteoporotic vertebral compression fractures(OVCFs) treated from July 2014 to July 2018 were retrospectively analyzed. There were 19 males and 23 females, aged from 62 to 80 years old with an average of 72 years. The vertebral fracture segment was T8-L5, including 30 lumbar vertebrae and 18 thoracic vertebrae. The course of the disease ranged from 3 d to 2 months. Twenty cases (20 vertebral bodies) were treated by single vertebroplasty (group A) and 22 cases (28 vertebral bodies) were treated by temperature contrast injection procedure(group B). The operative time, amount of bone cement injection, VAS score at 3 days after surgery, leakage rate and refracture rate were compared between two groups. RESULTS: The operative time, amount of bone cement injection and VAS score at 3 days after surgery in group B were (40.05±7.78) min, (3.93±0.19) ml, (3.55±0.74) points, respectively, and in group A were(38.90±6.81) min, (4.03±0.24) ml, (4.05±1.00) points, there was no significant difference between two groups(P>0.05). The leakage rate in group B was lower than that in group A (9.1% vs 40.0%, P<0.05). The refracture rate in group B was 9.1%(2/22), in group A was 15.0%(3/20), there was no significant difference between two groups (P>0.05). CONCLUSIONS: Temperature contrast injection procedure is an effective method to reduce the bone cement leakage in vertebroplasty.

A facile construction of bacterial cellulose/ZnO nanocomposite films and their photocatalytic and antibacterial properties.

Bacterial cellulose (BC) has numerous excellent properties but the absence of antibacterial activity restricts its applications in biomedical field. Therefore, in order to introduce the antibacterial characteristics into BC; herein, a facile method for incorporation of ZnO nanoparticles (ZnO-NPs) is presented. BC films were first immersed in zinc nitrate solution, followed by treating with NaOH solution, the BC loaded ZnO nanocomposite films were dried by a sheet former instrument at 80 °C for 20 min. The obtained BC/ZnO nanocomposites were characterized by different techniques. XRD results showed the hexagonal wurtzite structure of ZnO-NPs while FE-SEM results displayed the particle size of ZnO-NPs was ranging from 70 to 100 nm. Thermogravimetric study revealed the thermal stability of nanocomposite films. The nanocomposite exhibited photocatalytic activity and revealed 91% degradation of methyl orange (MO) under UV-irradiation within 2 h. Moreover, the nanocomposites demonstrated significant UV-blocking properties and showed antibacterial activities against tested Gram-positive and Gram-negative bacterial strains. This work provides a simple and novel method for the synthesis of BC/ZnO nanocomposite as a functional biomaterial.

Development of bacterial cellulose/chitosan based semi-interpenetrating hydrogels with improved mechanical and antibacterial properties.

In the present work, novel bacterial cellulose (BC) and chitosan (CS) semi-interpenetrating network (semi-IPN) hydrogels were prepared via blending the slurry of BC with CS solution followed by cross-linking with glutaraldehyde. The structure and properties of BC-CS hydrogels were characterized by different techniques including; FTIR, XRD, FE-SEM, TGA and rotational rheometry. The results indicated cross-linking of chitosan chains by glutaraldehyde while BC was physically connected to network forming semi-IPN hydrogels. Microscopic study of cross-sectional freeze-dried hydrogels showed microporous openings. BC-CS hydrogels exhibited higher thermal stability than pure BC film or CS hydrogel alone. The rheological results presented significant mechanical properties of semi-IPN hydrogels. Moreover, the hydrogels showed antibacterial properties against tested Gram-positive and Gram-negative bacteria. The antibacterial properties were dependent on the ratio of BC to CS. Hydrogels with 20% BC to CS reduced the viable colonies by ~88%. The development of this new class of BC-CS antibacterial, mechanically strong and stable soft-material could be a promising candidate for antibacterial applications.