Exploring naturally occurring ivy nanoparticles as an alternative biomaterial.

Arabinoglactan protein (AGP)-rich nanoparticles obtained from the sticky exudates of Hedera helix (English ivy), have shown promising potential to be used in nanomedicine owing to their excellent aqueous solubility, low intrinsic viscosity, biocompatibility, and biodegradability. In this study, the feasibilities of utilizing ivy nanoparticles (INPs) as nano-carriers for delivering chemotherapeutic drugs in cancer therapy and as nano-fillers to develop novel scaffolds for tissue engineering in regenerative medicine are evaluated. Via electrostatic and hydrophobic interactions, pH-responsive nanoconjugates are formed between the INPs and the doxorubicin (DOX) with an entrapment ratio of 77.9±3.9%. While the INPs show minimal cytotoxicity, the formed INP-DOX conjugates exhibit substantially stronger cytotoxic activity than free DOX against multiple cancer cell lines, suggesting a synergistic effect is established upon conjugation. The anti-cancer effects of the INP-DOX conjugates are further evaluated via in vivo xenograft assays by subcutaneously implanting DOX resistant cell line, SW620/Ad-300, into nude mice. The tumor volumes in mice treated with the INP-DOX conjugates are significantly less than those of the mice treated with free DOX. In addition, the INPs are further exploited as nano-fillers to develop fibrous scaffolds with collagen, via mimicking the porous matrix where the INPs are embedded under natural condition. Enhanced adhesion of smooth muscle cells (SMCs) and accelerated proliferation of mouse aortic SMCs are observed in this newly constructed scaffold. Overall, the results obtained from the present study suggest great potential of the INPs to be used as biocompatible nanomaterials in nanomedicine. The AGP-rich INP renders a glycoprotein architecture that is amenable for modification according to the functional designs, capable of being developed as versatile nanomaterials for extensive biomedical applications. STATEMENT OF SIGNIFICANCE: Naturally occurring organic nanomaterials have drawn increasing interest for their potential biomedical applications in recent years. In this study, a new type of naturally occurring nanoparticles obtained from the sticky exudates on the adventitious roots of English ivy (H. helix), was explored for its potential biomedical application. In particular, the feasibilities of utilizing ivy nanoparticles (INPs) as nano-carriers for delivering chemotherapeutic drugs in cancer therapy and as nano-fillers to develop novel scaffolds for tissue engineering in regenerative medicine were evaluated both in vitro and in vivo. Overall, the results obtained from the present study suggest the great potential of the INPs to be used as biocompatible nanomaterials in nanomedicine. This study may open a totally new frontier for exploring the biomedical application of naturally occurring nanomaterials.

[Effect of self-made colloid paste on gingival retraction in dogs].

PURPOSE: To evaluate the efficiency of self-made paste on gingival retraction in dogs as well as its potential clinical application. METHODS: Forty teeth from two mature dogs were prepared with 0.5 mm wide shoulder in the lip and buccal sides of the teeth, and then divided into four groups randomly. The gingival grooves of the four groups were filled with self-made colloid paste, Expasyl gingival retraction paste, gingival retraction cord, and medicated (15.5% Fe2SO4 solution) gingival retraction cord, respectively. The gingival grooves models before and after gingival retraction were analyzed using the image precise mapper instrument; the gingival width and height of the gingival groove were compared using SAS6.12 software package. RESULTS: The changes of gingival width of the gingival groove before and after gingival retraction were not significant between the four groups. However, the gingival height of the gingival groove in the medicated gingival retraction cord group increased significantly [(0.423 + or - 0.348) mm before gingival retraction and (0.623 + or - 0.278) mm after gingival retraction] compared with the other three groups. CONCLUSIONS: The self-made colloid paste for gingival retraction is efficient like Expasyl gingival retraction paste and gingival retraction cord with potential clinical application, while the medicated gingival retraction cord can induce gingival shrinkage. Supported by Research Fund of Science and Technology Bureau of Huangpu District,Shanghai.

[The influence of Streptococcus sanguis on corrosion resistance of magnetic retainer].

PURPOSE: To study the effect of Streptococcus sanguis on corrosion resistance of magnetic retainers in which are encapsulated with stainless steel artificial saliva. METHODS: A magnetic retainer was put in one culture flask,which was filled with artificial saliva.Ten of them were added Streptococcus sanguis suspension,the others were added PBS as control.The culture flasks were cultivated in incubator(36 degrees centigrade). 5 ml suspension was dislodged from each flask at the 3rd, 10th and 20th day. The quantity of Fe(3+) and Mn(2+) was detected.Statistical analysis of paired t test was performed with SPSS10.0 software package. RESULTS: When Streptococcus sanguis existed, the quantity of Fe(3+) and Mn(2+) was significantly higher than that in the control (P<0.01). CONCLUSION: The existence of Streptococcus sanguis destroys the corrosion resistance of magnetic retainers remarkably.

[The efficacy of dental plaque removed by using sonic electric toothbrush in children].

PURPOSE: To evaluate the efficacy of using sonic electric toothbrush to clean the teeth and control dental plaque in children. METHODS: 50 children aged 6 to 7 years old were selected and divided into 2 groups according to the use of sonic electric toothbrush and traditional manual toothbrush (control group). The numbers of dental plaque surface and PLI before and after tooth brushing were recorded. The data of the two groups were analyzed with SPSS10.0 software package for student's t test and chi(2) test. RESULTS: The ratio of dental plaque removal was 70.22% by using sonic electric toothbrush and 39.08% in the control group. The efficacy of dental plaque removal on the lingual and mesial buccal surface by using sonic electric toothbrush was 2 times greater than the control group. The PLI and the ratio of dental plaque removal were significantly different between the 2 groups (P<0.001). CONCLUSIONS: Sonic electric toothbrush can help children effectively remove dental plaque. It's an efficient instrument for oral care of children.

[Analysis of conservative therapies for posterior teeth with longitudinal fractures.].

PURPOSE: To explore the ideal method for conservative therapies of posterior teeth with longitudinal fracture. METHODS: The records of 297 cases undergoing conservative treatment of posterior teeth with longitudinal fracture were analyzed regarding to the position, etiology and the time of treatment from fracture and the causes of failure. RESULTS: 258 cases were conserved effectively and 39 cases were extracted due to failure.16 cases had failure 1 week after treatment. All the patients were followed up for 2 to 10 years, and the rate of success was 86.87%. CONCLUSION: With fixed early and appropriate treatment, the teeth can be conserved effectively and exert good masticatory function .