A novel one-pot synthesis and characterization of silk fibroin/α-calcium sulfate hemihydrate for bone regeneration

Funding Information: Funding: Support for this work was provided by the Ministry of Science and Technology, Taiwan MOST 109-2224-E-038-002. The APC was funded by MOST. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This study aims to fabricate silk fibroin/calcium sulfate (SF/CS) composites by one-pot synthesis for bone regeneration applications. The SF was harvested from degummed silkworm cocoons, dissolved in a solvent system comprising of calcium chloride:ethanol:water (1:2:8), and then mixed with a stoichiometric amount of sodium sulfate to prepare various SF/CS composites. The crystal pattern, glass transition temperature, and chemical composition of SF/CS samples were analyzed by XRD, DSC, and FTIR, respectively. These characterizations revealed the successful synthesis of pure calcium sulfate dihydrate (CSD) and calcium sulfate hemihydrate (CSH) when it was combined with SF. The thermal analysis through DSC indicated molecular-level interaction between the SF and CS. The FTIR deconvolution spectra demonstrated an increment in the β-sheet content by increasing CS content in the composites. The investigation into the morphology of the composites using SEM revealed the formation of plate-like dihydrate in the pure CS sample, while rod-like structures of α-CSH surrounded by SF in the composites were observed. The compressive strength of the hydrated 10 and 20% SF-incorporated CSH composites portrayed more than a twofold enhancement (statistically significant) in comparison to that of the pure CS samples. Reduced compressive strength was observed upon further increasing the SF content, possibly due to SF agglomeration that restricted its uniform distribution. Therefore, the one-pot synthesized SF/CS composites demonstrated suitable chemical, thermal, and morphological properties. However, additional biological analysis of its potential use as bone substitutes is required.publishersversionPeer reviewe

A novel sol-gel Bi2-xHfxO3+x/2 radiopacifier for mineral trioxide aggregates (MTA) as dental filling materials

Funding Information: The authors would like to thank Taipei Medical University Hospital for financially sup-porting this work under grant no. 110TMU-TMUH-16 and partially supported by MOST 109-2221-E-038-014. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Mineral trioxide aggregate (MTA) is well known as an effective root canal filling material for endodontics therapy. Within MTA, bismuth oxide (Bi2O3) serving as the radiopacifier still has biocompatibility concerns due to its mild cytotoxicity. In the present study, we tried to modify the Bi2O3 radiopacifier by doping hafnium ions via the sol-gel process and investigated the effects of different doping ratios (Bi2-xHfxO3+x/2, x = 0–0.3) and calcination temperatures (400–800 °C). We mixed various precursor mixtures of bismuth nitrate (Bi(NO3)3·5H2O) and hafnium sulfate (Hf(SO4)2) and controlled the calcination temperatures. The as-prepared Hf-doped Bi2O3 radiopaci-fier powders were investigated by thermogravimetric analysis (TGA), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Portland cement/radiopacifier/calcium sulfate (75/20/5) were mixed and set by deionized water (powder to water ratio = 3:1). Changes in radiopacity, diametral tensile strength (DTS), and in vitro cell viability of the hydrated MTA-like cement were carried out. The experimental results showed that the group containing radiopacifier from sol-gelled Bi/Hf (90/10) exhibited significantly higher radiopacity (6.36 ± 0.34 mmAl), DTS (2.54 ± 0.29 MPa), and cell viability (84.0±8.1%) (p < 0.05) when compared to that of Bi/Hf (100/0) powders. It is suggested that the formation of β-Bi7.78Hf0.22O12.11 phase with hafnium addition and calcining at 700 °C can prepare novel bismuth/haf-nium composite powder that can be used as an alternative radiopacifier for root canal filling mate-rials.publishersversionPeer reviewe

A comprehensive characterization of aggravated aging-related changes in T lymphocytes and monocytes in end-stage renal disease: The iESRD study

Background: Patients with end-stage renal disease (ESRD) exhibit a premature aging phenotype of the immune system. Nevertheless, the etiology and impact of these changes in ESRD patients remain unknown. Results: Compared to healthy individuals, ESRD patients exhibit accelerated immunosenescence in both T cell and monocyte compartments, characterized by a dramatic reduction in naïve CD4+ and CD8+ T cell numbers but increase in CD8+ TEMRA cell and proinflammatory monocyte numbers. Notably, within ESRD patients, aging-related immune changes positively correlated not only with increasing age but also with longer dialysis vintage. In multivariable-adjusted logistic regression models, the combination of high terminally differentiated CD8+ T cell level and high intermediate monocyte level, as a composite predictive immunophenotype, was independently associated with prevalent coronary artery disease as well as cardiovascular disease, after adjustment for age, sex, systemic inflammation and presence of diabetes. Levels of terminally differentiated CD8+ T cells also positively correlated with the level of uremic toxin p-cresyl sulfate. Conclusions: Aging-associated adaptive and innate immune changes are aggravated in ESRD and are associated with cardiovascular diseases. For the first time, our study demonstrates the potential link between immunosenescence in ESRD and duration of exposure to the uremic milieu

An Optical Tweezers-Based Single-Cell Manipulation and Detection Platform for Probing Real-Time Cancer Cell Chemotaxis and Response to Tyrosine Kinase Inhibitor PD153035

We presented an approach to address cancer cell chemotaxis and response to tyrosine kinase inhibitor PD153035 at the single-cell level. We applied an optical tweezer system together with the platform at the single-cell level to manipulate an epidermal growth factor (EGF)-coated bead positioned close to the filopodia to locally stimulate HT29 cells, the human colon cancer cell line overexpressing the EGF receptor (EGFR). To address cancer cell chemotaxis, a single-cell movement model was also proposed to quantify the propagation speed at the leading and trailing edges of the cell along the chemosensing axis. This study focused on three perspectives: probing the chemosensing process mediated by EGF/EGFR signaling, investigating the mode of locomotion during the EGF-coated bead stimulation, and quantifying the effect of PD153035 on the EGF–EGFR transport pathway. The results showed that the filopodial actin filament is a sensory system for EGF detection. In addition, HT29 cells may use the filopodial actin filament to distinguish the presence or absence of the chemoattractant EGF. Furthermore, we demonstrated the high selectivity of PD153035 for EGFR and the reversibility of binding to EGFR. We anticipate that the proposed single-cell method could be applied to construct a rapid screening method for the detection and therapeutic evaluation of many types of cancer during chemotaxis

Imaging and Histopathological Analysis of Microvascular Angiogenesis in Photodynamic Therapy for Oral Cancer

The objective of this study is to use imaging and histopathological analysis to characterize and monitor microvascular responses to photodynamic therapy (PDT). In vivo chicken chorioallantoic membranes (CAMs) and a stimulated malignant oral lesions animal model were used to determine the blood flow and the biological activities of Photofrin® (2.5 mg/kg) exposed to different laser power densities at 630 nm. The vascular changes, the velocity of the blood flow, the speckle flow index (SFI) of fluorescence changes, and ultrastructure damage in the microvasculature before and after PDT were recorded. The subcellular localization of Photofrin® revealed satisfactory uptake throughout the cytoplasm of human red blood cells at 10 s and 20 s before PDT. The mean blood-flow velocities of the veins and arteries were 500 ± 40 and 1500 ± 100 μm/s, respectively. A significant decrease in the velocities of the blood flow in the veins and arteries was detected in the CAM model after PDT. The veins and arteries of CAMs, exposed to the power densities of 80, 100, and 120 mW/cm2, had average blood-flow velocities of 100 ± 20, 60 ± 10, and 0 μm/s and 300 ± 50, 150 ± 30, and 0 μm/s, respectively. In the stimulated malignant oral lesions animal model, the treated tumors exhibited hemorrhage and red blood cell extravasation after PDT. The oxyhemoglobin and total hemoglobin levels decreased, which resulted in a decrease in tissue oxygen saturation, while the deoxyhemoglobin levels increased. PDT using Photofrin® has the ability to cause the destruction of the targeted microvasculature under nonthermal mechanisms selectively

Rehardening and the Protective Effect of Gamma-Polyglutamic Acid/Nano-Hydroxyapatite Paste on Surface-Etched Enamel

Many revolutionary approaches are on the way pertaining to the high occurrence of tooth decay, which is an enduring challenge in the field of preventive dentistry. However, an ideal dental care material has yet to be fully developed. With this aim, this research reports a dramatic enhancement in the rehardening potential of surface-etched enamels through a plausible synergistic effect of the novel combination of γ-polyglutamic acid (γ-PGA) and nano-hydroxyapatite (nano-HAp) paste, within the limitations of the study. The percentage of recovery of the surface microhardness (SMHR%) and the surface parameters for 9 wt% γ-PGA/nano-HAp paste on acid-etched enamel were investigated with a Vickers microhardness tester and an atomic force microscope, respectively. This in vitro study demonstrates that γ-PGA/nano-HAp treatment could increase the SMHR% of etched enamel to 39.59 ± 6.69% in 30 min. To test the hypothesis of the rehardening mechanism and the preventive effect of the γ-PGA/nano-HAp paste, the surface parameters of mean peak spacing (Rsm) and mean arithmetic surface roughness (Ra) were both measured and compared to the specimens subjected to demineralization and/or remineralization. After the treatment of γ-PGA/nano-HAp on the etched surface, the reduction in Rsm from 999 ± 120 nm to 700 ± 80 nm suggests the possible mechanism of void-filling within a short treatment time of 10 min. Furthermore, ΔRa-I, the roughness change due to etching before remineralization, was 23.15 ± 3.23 nm, while ΔRa-II, the roughness change after remineralization, was 11.99 ± 3.90 nm. This statistically significant reduction in roughness change (p < 0.05) implies a protective effect against the demineralization process. The as-developed novel γ-PGA/nano-HAp paste possesses a high efficacy towards tooth microhardness rehardening, and a protective effect against acid etching

Mechanical Properties and Biocompatibility of Urethane Acrylate-Based 3D-Printed Denture Base Resin

In this study, five urethane acrylates (UAs), namely aliphatic urethane hexa-acrylate (87A), aromatic urethane hexa-acrylate (88A), aliphatic UA (588), aliphatic urethane triacrylate diluted in 15% HDD (594), and high-functional aliphatic UA (5812), were selected to formulate five UA-based photopolymer resins for digital light processing (DLP)-based 3D printing. Each UA (40 wt%) was added and blended homogenously with ethoxylated pentaerythritol tetraacrylate (40 wt%), isobornyl acrylate (12 wt%), diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (3 wt%), and a pink acrylic (5 wt%). Each UA-based resin specimen was designed using CAD software and fabricated using a DLP 3D printer to specific dimensions. Characteristics, mechanical properties, and cytotoxicity levels of these designed UA-based resins were investigated and compared with a commercial 3D printing denture base acrylic resin (BB base) control group at different UV exposure times. Shore hardness-measurement data and MTT assays were analyzed using a one-way analysis of variance with Bonferroni’s post hoc test, whereas viscosity, maximum strength, and modulus were analyzed using the Kruskal–Wallis test (α = 0.05). UA-based photopolymer resins with tunable mechanical properties were successfully prepared by replacing the UA materials and the UV exposure times. After 15 min of UV exposure, the 5812 and 594 groups exhibited higher viscosities, whereas the 88A and 87A groups exhibited lower viscosities compared with the BB base group. Maximum flexural strength, flexural modulus, and Shore hardness values also revealed significant differences among materials (p < 0.001). Based on MTT assay results, the UA-based photopolymer resins were nontoxic. In the present study, mechanical properties of the designed photopolymer resins could be adjusted by changing the UA or UV exposure time, suggesting that aliphatic urethane acrylate has good potential for use in the design of printable resins for DLP-type 3D printing in dental applications

Biophotonic Effects of Low-Level Laser Therapy at Different Wavelengths for Potential Wound Healing

Our objective was to assess the effect of low-level laser therapy (LLLT) administered using a diode laser on the growth processes of human fibroblast cells involved in wound healing. Initially, studies were conducted using a diode laser at wavelengths of 633, 520, and 450 nm with an irradiance of 3 mW/cm2. The distance between the light source and culture plate was 3 cm. The mechanism(s) of action of the diode laser illumination on human fibroblast cells were studied by examining different wavelengths to determine the relevant light parameters for optimal treatment. In addition, the percentages of fibroblast-mediated procollagen and matrix metallopeptidase (MMP)-1, -2, and -9 production were compared. In the clinical study, the changes in basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and fibroblast collagen production were assessed in 60 patients with complicated wounds who received LLLT (633 nm). No statistically significant difference was observed between red light versus green and blue light in the viability analysis. In addition, the effects of LLLT on the cell cultures of fibroblast cells in vitro demonstrated a decrease in the relative expression of MMP-1, -2, and -9 while using light with a wavelength of 633 nm. In the clinical study, 633 nm diode laser LLLT at 2&ndash;8 J/cm2 was administered to 60 patients with complicated wounds; all patients showed increased levels of bFGF and VEGF and the occurrence of collagen synthesis. Our studies demonstrated that LLLT might affect fibroblast cell growth processes involved in wound healing