The results showed that the deciding factor is the culture medium in which the bacteria and the graphene oxide (GO) are incubated at the initial manipulation step. These findings allow better use of GO and GO-based materials more and be able to clearly apply them in the field of biomedical nanotechnology. To study the use of GO sheets applied in the field of biomedical nanotechnology, this study determines whether GO-based materials [GO, GO-polyoxyalkyleneamine (POAA), and GO-chitosan] stimulate or inhibit bacterial growth in detail. It is found that it depends on whether the bacteria and GO-based materials are incubated with a nutrient at the initial step. This is a critical factor for the fortune of bacteria. GO stimulates bacterial growth and microbial proliferation for Gram-negative and Gram-positive bacteria and might also provide augmented surface attachment for both types of bacteria. When an external barrier that is composed of GO-based materials forms around the surface of the bacteria, it suppresses nutrients that are essential to microbial growth and simultaneously produces oxidative stress, which causes bacteria to die, regardless of whether they have an outer-membrane-Gram-negative-bacteria or lack an outer-membrane-Gram-positive-bacteria, even for high concentrations of biocompatible GO-POAA. The results also show that these GO-based materials are capable of inducing reactive oxygen species (ROS)-dependent oxidative stress on bacteria. Besides, GO-based materials may act as a biofilm, so it is hypothesized that they suppress the toxicity of low-dose chitosan. Graphene oxide is not an antimicrobial material but it is a general growth enhancer that can act as a biofilm to enhance bacterial attachment and proliferation. However, GO-based materials are capable of inducing ROS-dependent oxidative stress on bacteria. The applications of GO-based materials can clearly be used in antimicrobial surface coatings, surface-attached stem cells for orthopedics, antifouling for biocides and microbial fuel cells and microbial electro-synthesis.

Objective: Angiogenesis plays a part in the pathogenesis of rheumatoid arthritis (RA), and nanogold inhibits the activity of an angiogenic factor, vascular endothelial growth factor (VEGF). We therefore investigated whether intraarticular delivery of nanogold ameliorates collagen‐induced arthritis (CIA) in rats.Methods: Binding of 13‐nm nanogold to VEGF in human RA synovial fluid (SF) and its effects on RA SF–induced endothelial cell proliferation and migration were assessed. Nanogold was administered intraarticularly to rats with CIA before the onset of arthritis. Progression of CIA was monitored by measures of clinical, radiologic, and histologic changes. In addition, the microvessel density and extent of infiltrating macrophages as well as levels of tumor necrosis factor α (TNFα) and interleukin‐1β (IL‐1β) in the ankle joints were determined.Results: Nanogold bound to VEGF in RA SF, resulting in inhibition of RA SF–induced endothelial cell proliferation and migration. Significant reductions in ankle circumference, articular index scores, and radiographic scores were observed in the nanogold‐treated rats with CIA compared with their control counterparts. In addition, the histologic score (of synovial hyperplasia, cartilage erosion, and leukocyte infiltration), microvessel density, macrophage infiltration, and levels of TNFα and IL‐1β were also significantly reduced in the ankle joints of nanogold‐treated rats.Conclusion: Our results are the first to demonstrate that intraarticular administration of nanogold ameliorates the clinical course of CIA in rats. Nanogold exerted antiangiogenic activities and subsequently reduced macrophage infiltration and inflammation, which resulted in attenuation of arthritis. These results demonstrate proof of principle for the use of nanogold as a novel therapeutic agent for the treatment of RA.

Objective: MicroRNA (miRNA) plays a role in autoimmune diseases. MiRNA‐223 (miR‐223) is up‐regulated in patients with rheumatoid arthritis (RA) and is involved in osteoclastogenesis, which contributes to erosive disease. The aim of this study was to test the feasibility of using lentiviral vectors expressing the miR‐223 target sequence (miR‐223T) to suppress miR‐223 activity as a therapeutic strategy in a mouse model of collagen‐induced arthritis (CIA).Methods: Levels of miR‐223 in the synovial tissue of patients with RA or osteoarthritis (OA), as well as in the ankle joints of mice with CIA, were determined by quantitative reverse transcriptase–polymerase chain reaction (RT‐PCR). Lentiviral vectors expressing miR‐223T (LVmiR‐223T) or luciferase short hairpin RNA (LVshLuc) as a control vector were injected intraperitoneally into mice with CIA. Treatment responses and disease‐related bone mineral density were monitored. Levels of nuclear factor 1A (NF‐1A), a direct target of miR‐223, and macrophage colony‐stimulating factor receptor (M‐CSFR), which is critical for osteoclastogenesis, were measured by immunohistochemistry and quantitative RT‐PCR. Osteoclasts were assessed by tartrate‐resistant acid phosphatase staining.Results: MiR‐223 expression was significantly higher in the synovium of RA patients and in the ankle joints of mice with CIA as compared to OA patients and normal mice. LVmiR‐223T treatment reduced the arthritis score, histologic score, miR‐223 expression, osteoclastogenesis, and bone erosion in mice with CIA. Down‐regulation of miR‐223 with concomitant increases in NF‐1A levels and decreases in M‐CSFR levels was detected in the synovium of LVmiR‐223T–treated mice.Conclusion: This study is the first to demonstrate that lentivirus‐mediated silencing of miR‐223 can reduce disease severity of experimental arthritis. Furthermore, our results indicate that inhibition of miR‐223 activity should be further explored as a therapeutic strategy in RA.

Objective: Kallistatin has been shown to be an angiogenesis inhibitor. In this study, we investigated whether adenovirus‐mediated kallistatin gene delivery has a prophylactic effect in a rat arthritis model.Methods: Adenovirus containing the human kallistatin gene (AdHKBP) was injected intraarticularly into ankle joints before the onset of arthritis in a rat model. The effect of kallistatin gene transfer on endothelial cell proliferation in joint extracts was assayed. The response to kallistatin treatment was determined according to clinical parameters, including ankle circumference, articular index, and radiographic scores. Hematoxylin and eosin staining was performed in order to score joint tissues and count neutrophil numbers. In addition, small vessels were quantified by identification of von Willebrand factor–positive endothelial cells. The inflammatory responses were determined by measuring tumor necrosis factor α (TNFα) and interleukin‐1β (IL‐1β) levels in ankle homogenates.Results: The expression of recombinant human kallistatin in rat ankle joints after gene transfer was identified by immunohistochemical analysis and Western blotting. Significant reductions in the ankle circumference, articular index, and radiographic score were observed in AdHKBP‐treated rats compared with control rats treated with the adenoviral plasmid carrying green fluorescent protein. Kallistatin gene transfer also significantly ameliorated the histologic scores in ankle joints and reduced vessel density and neutrophil numbers. The inhibitory effect of kallistatin on the accumulation of inflammatory cells in ankle joints was accompanied by reduced TNFα and IL‐1β levels in joint homogenates. Furthermore, an in vitro experiment showed that the proliferation of endothelial cells was markedly inhibited by the addition of AdHKBP‐treated joint extract to the culture media, supporting a role of kallistatin in inhibiting angiogenesis.Conclusion: This study demonstrates that kallistatin gene therapy has a prophylactic effect in inhibiting arthritis in the rat ankle. Kallistatin inhibits arthritis through its antiangiogenesis and antiinflammation activities. These results implicate potential therapeutic applications for suppression of arthritis by kallistatin gene therapy.