Lignocellulosic-Based Nanoparticles with Photoluminescent Properties for Bioimaging

10 Pág.Natural and renewable resources from plants or animals are an important source of biomaterials due to their biocompatibility and high availability. Lignin is a biopolymer present in the biomass of plants, where it is intertwined and cross-linked with other polymers and macromolecules in the cell walls, generating a lignocellulosic material with potential applications. We have prepared lignocellulosic-based nanoparticles with an average size of 156 nm that exhibit a high photoluminescence signal when excited at 500 nm with emission in the near-infrared (NIR) region at 800 nm. The advantage of these lignocellulosic-based nanoparticles is their natural luminescent properties and their origin from rose biomass waste, which eliminates the need for encapsulation or functionalization of imaging agents. Moreover, the in vitro cell growth inhibition (IC50) of lignocellulosic-based nanoparticles is about 3 mg/mL, and no in vivo toxicity was registered up to 57 mg/kg, which suggests that they are suitable for bioimaging applications. In addition, these nanoparticles can circulate in the blood and are excreted in urine. The combined high luminescence signal in NIR, small size, low in vitro toxicity, low in vivo toxicity, and blood circulation support the potential of lignin-based nanoparticles as a novel bioimaging agent.We would like to thank Yachay Tech University, through the internal grant CHEM19-15, for its support of some facilities to develop this project. Received: ((will be filled in by the editorial staff)) Revised: ((will be filled in by the editorial staff)) Published online: ((will be filled in by the editorial staff)Peer reviewe

Does fear of infection affect people's dental attendance during COVID-19? A Chinese example to examine the association between COVID anxiety and dental anxiety

Introduction: Little is known about the psychological and behavioural effect of COVID-19 pandemic on patients and their reaction to dental visiting. Patients may delay attendance due to fears of contracting the corona virus at the dentist. The study aims to confirm the psychometric properties of the two COVID-19scales and then use dental patient responses to assess the associations between the COVID-19 Anxiety Scale (CAS), dental anxiety (MDAS) and the clinical care COVID-19 Anxiety (CCAS).Methods: A cross-sectional study was conducted among 503 patients visiting a polyclinic of a stomatological hospital in East China in 2020. Patients completed a survey consisting of demographical information, dental attendance, COVID-19 Anxiety Scale, Clinical Care COVID-19 Anxiety Scale and Modified Dental Anxiety Scale. Confirmatory factor analysis was conducted to determine the psychometric characteristics. A further structural model was tested with the combined measurement model and a path analysis was calculated.Results: The sample (n = 503) consisted of more women than men (63% vs. 37%). A fifth of the sample (21%) claimed regular dental attendance and just over a third (35%) reported delaying their dental visit due to the pandemic. Our analysis showed that both CAS and CCAS possessed a unidimensional structure. The MDAS was divided into anticipatory and treatment components as separate latent variables. The anticipatory component (MDAS_A) had some association to CCAS through its expression on treatment dental anxiety (MDAS_T). General anxiety about COVID (CAS) had a direct effect on CCAS. The fit statistics were acceptable [Chi-square = 183.27, df = 68, p < .001; CFI = 0.973; RMSEA = 0.058(95%CIs: 0.048–0.068)] and the Standardised Root Mean Square Residuals (SRMR) index was 0.041.Discussion: The Clinical Care COVID-19 Anxiety has shown satisfactory psychometric properties. Both dental anxiety and general anxiety about the pandemic have strong associations to patients’ fear of contracting corona virus when using dental facilities. Our study has practical implications to help healthcare providers better understand how environmental stressors influence patients’ overall concerns on infection risks and appropriate dental treatments during the pandemic

Strengthen the bonding of self-glazed zirconia to enamel by sol–gel coating

Sol–gel coating technology was applied to modify the bonding surface of self-glazed zirconia (SZ). Its effect on the bond strength of SZ to enamel was evaluated in vitro in comparison with the conventional milled zirconia treated by airborne-particle abrasion (CZa) and the heat-pressed lithium disilicate glass-ceramics treated by etching and silanization (LDe). All ceramic specimens were bonded to the etched bovine enamel with adhesive resin cement. Shear bond strength of both sol–gel coated SZ groups with different strategies (SZc1 and SZc2) was 20.00 ± 7.07 MPa and 18.32 ± 3.63 MPa, respectively, which was comparable to that of LDe, 18.44 ± 2.27 MPa (p > 0.05) and significantly higher than that of CZa, 11.72 ± 1.48 MPa, and SZ, 3.06 ± 1.66 MPa (p < 0.05). Lots of voids between zirconia clusters were observed on the bonding surface of SZc1, yet that of SZc2 showed homogeneous honeycomb nanoporous structure. All groups exhibited mixed failure except SZ, and the fracture surfaces of SZc1, SZc2, and LDe showed better wettability than CZa. Sol–gel coating could improve the bond strength of SZ to enamel, and the sol–gel coated SZ might have the potential to make minimally invasive restorations

Functionalization of deproteinized bovine bone with a coating-incorporated depot of BMP-2 renders the material efficiently osteoinductive and suppresses foreign-body reactivity

The repair of critical-sized bony defects remains a challenge in the fields of implantology, maxillofacial surgery and orthopaedics. As an alternative bone-defect filler to autologous bone grafts, deproteinized bovine bone (DBB) is highly osteoconductive and clinically now widely used. However, this product suffers from the disadvantage of not being intrinsically osteoinductive. In the present study, this property was conferred by coating DBB with a layer of calcium phosphate into which bone morphogenetic protein 2 (BMP-2) was incorporated. Granules of DBB bearing a coating-incorporated depot of BMP-2--together with the appropriate controls (DBB bearing a coating but no BMP-2; uncoated DBB bearing adsorbed BMP-2; uncoated DBB bearing no BMP-2)--were implanted subcutaneously in rats. Five weeks later, the implants were withdrawn for a histomorphometric analysis of the volume densities of (i) bone, (ii) bone marrow, (iii) foreign-body giant cells and (iv) fibrous capsular tissue. Parameters (i) and (ii) were highest, whilst parameters (iii) and (iv) were lowest in association with DBB bearing a coating-incorporated depot of BMP-2. Hence, this mode of functionalization not only confers DBB with the property of osteoinductivity but also improves its biocompatibility--thus dually enhancing its clinical potential in the repair of bony defects

Bone morphogenetic protein-2 incorporated calcium phosphate graft promotes peri-implant bone defect healing in dogs: A pilot study

Objectives: The evaluation of three different drug delivery modes of bone morphogenetic protein-2 (BMP-2) in healing peri-implant bone defects in beagle dogs. BMP-2 was incorporated in or onto calcium phosphate (CaP) granules in various ways: (i) directly on the outer layer of granules CaP: as an adsorbed depot; (ii) during the entire precipitation process of CaP: an internally incorporated depot; or (iii) during the biomimetic coating precipitation of BMP-2 on the surface of CaP granules: as a coating incorporated depot. Material and Methods: After extraction of the lower molars and wound healing in 6 male beagle dogs, 36 implants were placed (n = 6 animal per group). Peri-implant bone defects were induced. The following treatment groups were evaluated: no treatment; air abrasive surface cleaning (SC) using hydroxyapatite; SC and the subsequent filling of the defect with CaP without BMP-2; SC plus the subsequent filling of the defect with CaP adsorbed BMP-2; SC plus the subsequent filling of the defect with CaP internally incorporated BMP-2; SC plus the subsequent filling of the defect with CaP coating incorporated BMP-2. Histological and histomorphometric analyses were carried out to quantify and compare the changes in bone tissue surrounding the treated implants. Results: In Group 1 with no treatment, four implants were lost. Group 5 with the SC and the subsequent filling of the defect with internally incorporated BMP-2 biomimetically prepared CaP (BioCaP), whereby the BMP-2 is incorporated in the entire volume of all BioCaP particles, showed overall the best results to regenerate bone around the implants. Conclusion: This study concluded that the group treated with SC plus the subsequent filling of the defect with CaP BMP-2 internally incorporated BMP-2, whereby BMP-2 has been incorporated in the entire volume of all CaP particles, showed overall the best results when aiming to regenerate bone around the implants

Plaque removal efficacy of a compacted dual-head power toothbrush: A split-mouth randomized clinical trial

PURPOSE: To evaluate the plaque removal efficacy of a compacted dual-head power toothbrush (DH) in comparison with a single-head power toothbrush (SH). METHODS: 24 healthy university students were included in this split-mouth and single-center clinical trial. The DH and SH were randomly assigned to brush the left/right half mouth in the first visit. Testing time points were 30 and 60 seconds. Additionally, 15 and 45 seconds were set for the DH period. The overall, buccal, lingual, gingival marginal, and proximal plaque scores at different time points were recorded and determined by Rustogi Modification of the Navy Plaque Index. To avoid the influence of the right handedness, subjects were brushed in the second visit after 4 weeks, and the SH and the DH were assigned to the right/left half mouth in an opposite period to that of the first visit. RESULTS: 21 participants completed this study. Overall plaque score reductions of the SH and DH were 29% and 59% (P< 0.05) at 30 seconds, and the reductions were 47% and 77% respectively (P< 0.05) at 60 seconds. Using the DH for 45 seconds reduced significantly more overall, buccal, lingual, and gingival marginal plaque than that of using SH for 60 seconds (P< 0.05). The SH reduced plaque scores significantly less in the right and lower dentitions than left and upper dentitions respectively, while DH reduced comparable plaque scores between these dentitions. The DH is more effective in removing overall, buccal, lingual, gingival marginal, and proximal plaque in healthy university students than the SH, meanwhile DH showed comparable overall plaque reduction rates between different regions of the dentitions. CLINICAL SIGNIFICANCE: This compact dual-head power toothbrush provides a new option to carry out daily plaque control effectively

Turnover behavior and intention among dentists and medical doctors: a cross-sectional study in China

Abstract Background Retention of doctors is a global challenge and doctors working in different departments may face different problems. The study aimed to explore the turnover behavior and intention and correlated factors among Chinese dentists and medical doctors in other clinical fields. Methods A cross-sectional study was conducted online in 5 regions of China from March 12th to April 12th, 2020. The questionnaire included 3 parts, socio-demographic characteristics, turnover behavior and intention, and concerns about work-related factors. Chi-square test and/or Wilcoxon Mann-Whitney test were applied for comparison, and binary logistic regression was used for finding the factors. Results A total of 2428 eligible questionnaire were received, comprising 1954 responses from dentists and 474 from medical doctors. Rates of turnover behavior among dentists and medical doctors were 2.87% and 6.96%, respectively. Similarly, rates of turnover intention were 51.79% among dentists and 71.20% among medical doctors. Educational level was negatively correlated with turnover behavior of both medical doctors and dentists, and concern about salary was a unique negatively correlated factor for dentists. Age was negatively correlated with turnover intention in both medical doctors and dentists. Conversely, concerns about workload and doctor-patient relationship were positively correlated with turnover intention in both groups. Concern about salary was the distinct correlated factor of medical doctors’ turnover intention, while gender and annual household income were correlated with turnover intention among dentists. Conclusions Low turnover rate but high turnover intention rate was the current status of Chinese doctors’ employment. Turnover behavior and intention were more optimistic among dentists than medical doctors. Factors related to turnover behavior and turnover intention were not identical among dentists and medical doctors. Therefore, personalized retention measures were necessary for dentists and medical doctors

Heterodimeric BMP-2/7 Antagonizes the Inhibition of All-Trans Retinoic Acid and Promotes the Osteoblastogenesis

<div><p>Objectives</p><p>Hypervitaminosis A and alcoholism can result in a low mineral density and compromised regenerative capacity of bone, thus delaying implant osteointegration. The inhibitory effect of all-trans retinoic acid on osteoblastogenesis is considered to be one of the mechanisms. We hypothesized that heterodimeric bone morphogenetic protein-2/7 could antagonize all-trans retinoic acid and enhance osteoblastogenesis, with an aim to accelerate and enhance bone regeneration and implant osteointegration.</p><p>Materials and Methods</p><p>We applied 5 ng/ml or 50 ng/ml bone morphogenetic protein-2/7 to restore the osteoblastogenesis of pre-osteoblasts (MC3T3-E1 cell line) that was inhibited by 1 µM all-trans retinoic acid. We evaluated the efficacy by assessing cell numbers (proliferation), alkaline phosphatase activity (a marker for early differentiation), osteocalcin (a marker for late differentiation), calcium deposition (a marker for final mineralization) and the expression of osteoblastogenic genes (such as Runx2, Collagen Ia, alkaline phosphatase and osteocalcin) at different time points.</p><p>Results</p><p>All-trans retinoic acid significantly inhibited the expression of all the tested osteoblastogenic genes and proteins except alkaline phosphatase activity. In the presence of ATRA, 50 ng/ml bone morphogenetic protein-2/7 not only completely restored but also significantly enhanced all the osteoblastogenic genes and proteins. On the 28^th day, mineralization was completely inhibited by all-trans retinoic acid. In contrast, 50 ng/ml BMP-2/7 could antagonize ATRA and significantly enhance the mineralization about 2.5 folds in comparison with the control treatment (no ATRA, no BMP2/7).</p><p>Conclusions</p><p>Heterodimeric bone morphogenetic protein-2/7 bears a promising application potential to significantly promote bone regeneration and implant osteointegration for the patients with hypervitaminosis A and alcoholism.</p></div

The cell numbers of murine calvarial pre-osteoblasts (MC3T3-E1 cells) per well under the different treatments.

<p>1) no ATRA, no BMP-2/7; 2) 1 µM ATRA, no BMP-2/7; 3) 1 µM ATRA, 5 ng/ml BMP-2/7; 4) 1 µM ATRA, 50 ng/ml BMP-2/7; 5) no ATRA, 5 ng/ml BMP-2/7; 6) no ATRA, 50 ng/ml BMP-2/7 for 1 day and 4 days. All data are presented as mean values together with the standard deviation (SD). *: <i>p</i><0.05, **: <i>p</i><0.01, ***: <i>p</i><0.001.</p