Biophotonic Effects of Low-Level Laser Therapy on Adipose-Derived Stem Cells for Soft Tissue Deficiency.

PURPOSES: The objectives of this study are to use diode lasers for low-level laser therapy (LLLT) and to assess its applicability and effects in adipose-derived stem cell (ADSC) growth processes. METHODS: Studies were conducted on the diode laser with wavelengths of 622.7, 527.1, and 467.3 nm. The mechanism of action of LLL illumination was studied on ADSCs, isolated from human tissue, and then cultured by examining different wavelengths to determine the relevant light parameters for optimal responses. We used enzyme-linked immunosorbent assay and real-time polymerase chain to determine the percentages of fibroblast-mediated procollagen type 1 and matrix metallopeptidase 1 (MMP-1), MMP-2, and MMP-9 production at different wavelengths. The levels of lactate dehydrogenase produced by ADSCs after LLL illumination were assessed as well. Clinical results from 20 patients treated for soft tissue deficiency were collected for assessment of ADSC-assisted lipotransfer. RESULTS: Low-level laser (622.7 nm) illumination on cell cultures in vitro increased ADSCs proliferation, type 1 procollagen expression, collagen production, as well as MMP-1, MMP-2, and MMP-9 relative expression. Statistical analysis demonstrated a significant difference in red light (622.7 nm) versus green light (527.1 nm) and blue light (467.3 nm, P < 0.05). No significant differences were noted between the effects of green and blue lights. In clinical application, all patients attained significant improvement with treatment in the final outcome assessment after 6 months. CONCLUSIONS: Low-level laser illumination may affect ADSCs growth processes and ADSC-assisted lipotransfer for soft tissue deformity, scar treatment, wound healing, and other reconstructive surgery.

Surfactin induces ER stress-mediated apoptosis via IRE1-ASK1-JNK signaling in human osteosarcoma.

Osteosarcoma, one of primary bone tumor in children and young adults, has poor prognosis and drug resistances to chemotherapy. In order to reinforce the conventional therapies and antagonize the osteosarcoma in patients, a novel strategy is required for developing a new treatment. In this study, surfactin, a natural product from Bacillus subtilis, showed the efficiency of cell death in osteosarcoma, but not in normal cells. Surfactin triggers ER stress mechanism by promoting the aberrant Ca2+ release from ER lumen and ER-signaling to mitochondrial dysfunction following caspases activation mediating cell apoptosis. Surfactin-induced ER stress not only upregulated of glucose-regulated protein 78/94 and IRE1-ASK1-JNK pathway but also leading to calpains and Bcl-2 proteins family involving the release of cytochrome c. The releases into cytosol trigger the cleavage of caspase-9 and caspase-3 to induce cell apoptosis. In this study, surfactin demonstrated the potential functions to trigger the ER stress, ER stress-associated IRE1-ASK1-JNK signaling pathway, mitochondrial dysfunction, and caspase activations leading to programmed cell apoptosis. Importantly, implicating the signaling pathway that regulates the connection between ER stress and mitochondrial dysfunction causing apoptosis associated with surfactin. These results indicated a potential application of surfactin strengthen current conventional therapies.

A High-Efficiency Driver Circuit for a Gas-Sensor Microheater Based on a Switch-Mode DC-to-DC Converter.

Low power consumption is one of the critical factors for successful Internet of Things (IoT) applications. In such applications, gas sensors have become a main source of power consumption because energy conversion efficiency of the microheater is relative over a wide range of operating temperatures. To improve the energy-conversion efficiency of gas-sensor microheaters, this paper proposes integrated switch-mode DC-to-DC power converter technology which we compare with traditional driving methods such as pulse-width modulation and the linear mode. The results indicate that energy conversion efficiency with this proposed method remains over 90% from 150 °C to 400 °C when using a 3.0, 4.2 and 5.0 V power supply. Energy-conversion efficiency increases by 1-74% compared with results obtained using the traditional driving methods, and the sensing film still detects alcohol and toluene at 200 °C and 280 °C, respectively, with high energy conversion efficiency. These results show that the proposed method is useful and should be further developed to drive gas-sensor microheaters, and then integrated into the circuits of the complementary metal-oxide-semiconductor micro electro mechanical systems (CMOS-MEMS).

Osseointegration of titanium implants with SLAffinity treatment: a histological and biomechanical study in miniature pigs.

PURPOSE: Electrochemical oxidation following sandblasting and acid-etching (SLA) treatment has received interest as a surface modification procedure for titanium (Ti) implants (denoted as an SLAffinity surface); however, little information is available on its impacts on the in vivo performance of SLAffinity-Ti implants. The present study evaluated the osseointegration and biomechanical bone-tissue response to SLAffinity-Ti implants with micro- and nanoporous oxide layers. MATERIALS AND METHODS: The interaction between blood and the tested implants was examined. In total, 144 implants with the following surfaces were used: a standard machined (M-Ti), an SLA-Ti, and an SLAffinity-Ti surface. For each animal, four implants (one M-Ti, one SLA-Ti, and two SLAffinity-Ti) were inserted into the mandibular canine-premolar area for histomorphometric observations and another four implants were inserted into the flat surface on the anteromedial aspect of the rear tibia for removal torque (RT) tests. After 2, 4, and 8 weeks of implantation, histomorphometric and RT tests were conducted. RESULTS: Interactions between blood and implants were better for implants with the SLAffinity-Ti surface. RT tests showed a significant improvement in fixation strength for SLAffinity-Ti implants (84.5 ± 8.7 N-cm) after 8 weeks compared to M-Ti (62.95 ± 11.5 N-cm) and SLAffinity-Ti (76.1 ± 6.6 N-cm) implants. A histological evaluation showed that osseous integration had occurred with all implants after 8 weeks. SLAffinity-Ti implants exhibited 28.5 ± 6.2 % bone-to-implant contact (BIC) at 2 weeks and 84.3 ± 8.1 % at 8 weeks. M-Ti implants exhibited BIC levels of 17.0 ± 5.4 and 76.5 ± 6.3 %, whereas SLA-Ti implants exhibited BIC levels of 28.5 ± 6.2 and 81.1 ± 8.4 % at corresponding time intervals. In terms of the peri-implant bone area (BA), values for SLAffinity-Ti implants ranged from 29.5 ± 4.1 to 88.3 ± 3.0 %. For M-Ti implants, values ranged from 20.3 ± 5.5 to 81.7 ± 4.2 %. For SLA-Ti implants, values ranged from 23.0 ± 3.5 to 84.0 ± 3.6 %. CONCLUSIONS: Electrochemical oxidation increased the oxide layers and improved the blood interaction with SLAffinity-Ti implants, resulting in significantly higher bone apposition with the SLAffinity-Ti implants after 2 and 8 weeks of healing. An increase in resistance for the RT of SLAffinity-Ti implants over the 8-week healing period was also observed. CLINICAL RELEVANCE: The use of SLAffinity-Ti implants has potential for improvement of early osseointegration.

Research of StemBios Cell Therapy on Dental Implants Containing Nanostructured Surfaces: Biomechanical Behaviors, Microstructural Characteristics, and Clinical Trial.

PURPOSE: The aim of the present study was to examine the osseointegration in low-density bone tissue for SLAffinity-treated implants with StemBios (SB) cell therapy. MATERIALS AND METHODS: The morphologies of SLAffinity-treated surfaces were characterized using scanning electron microscopy. In the animal model, implants were installed in the mandibular canine-premolar area of 12 miniature pigs. Each pig received 3 implants of machine, sand blasted, large grit, and acid etched, and SLAffinity-treated implants. In the clinical trial, 10 patients received 1 SLAffinity-treated implant in the maxilla in the posterior area and 1 patient with low bone tissue density received 2 SLAffinity-treated implants with SB cell therapy. Resonance frequency analysis and computed tomography were assessed monthly over the first 3 months after implant placement. RESULTS: The results demonstrated that surface treatment significantly affected early osseointegration in patients who received SB cell therapy. SB cell therapy transferred the stress caused by the implant more uniformly, and the stress decreased with healing time. SLAffinity-treated implants also proved clinically successful after the 3 months. CONCLUSION: The SLAffinity treatments enhanced osseointegration significantly, especially at early stages of bone tissue healing with SB cell therapy.

Gene selection for cancer identification: a decision tree model empowered by particle swarm optimization algorithm.

BACKGROUND: In the application of microarray data, how to select a small number of informative genes from thousands of genes that may contribute to the occurrence of cancers is an important issue. Many researchers use various computational intelligence methods to analyzed gene expression data. RESULTS: To achieve efficient gene selection from thousands of candidate genes that can contribute in identifying cancers, this study aims at developing a novel method utilizing particle swarm optimization combined with a decision tree as the classifier. This study also compares the performance of our proposed method with other well-known benchmark classification methods (support vector machine, self-organizing map, back propagation neural network, C4.5 decision tree, Naive Bayes, CART decision tree, and artificial immune recognition system) and conducts experiments on 11 gene expression cancer datasets. CONCLUSION: Based on statistical analysis, our proposed method outperforms other popular classifiers for all test datasets, and is compatible to SVM for certain specific datasets. Further, the housekeeping genes with various expression patterns and tissue-specific genes are identified. These genes provide a high discrimination power on cancer classification.

Quantifying membrane permeability of amphotericin B ion channels in single living cells.

Recently, the structure-function relationships between amphotericin B (AmB) and ergosterol have been solved using synthetic techniques that require a mycosamine-mediated direct binding interaction between AmB and ergosterol to form AmB ion channels. However, studies to directly probe the AmB-induced membrane permeability changes have not been conducted. In the present work, we investigate the following fundamental question: does AmB induce concentration- and time-dependent permeability changes across ergosterol-containing membranes? Herein, we employ fluorescent dyes of known average diameter to quantify the diameters of AmB ion channels. In addition, we take a single-particle tracking approach to define the intracellular microrheology in the absence and presence of AmB ion channels. Present results show that increasing AmB concentration tends to increase the preferential accumulation of AmB ion channels in the presence of the excess membrane-embedded ergosterol. We found that AmB induces time-dependent membrane permeability; increases approaching 50% in both the velocity fluctuations and diffusion coefficients of vesicles occur on the same time scale as the efflux of potassium ions (≅30min). Furthermore, we propose a two-dimensional, semi-regular tessellation model to geometrically assess the pore size of the AmB ion channels in response to the AmB dose. This approach offers one possibility for the design of AmB ion channels with tunable aqueous pore size, which could provide an opportunity to replace damaged membrane water channels of the aquaporin family in future applications.

Cellular response of calcium phosphate bone substitute containing hydroxyapatite and tricalcium phosphate.

PURPOSE: This study developed calcium phosphate bone substitutes and their microstucture and in vitro cell response were evaluated in comparison with commercial hydroxyapatite (HA). MATERIALS: HA powder was ball-milled and then sintered to transfer into the calcium phosphate bulks (CPB). The density, hardness, and microstructure of the CPB were investigated. The viability and proliferation of MG63 osteoblast-like cells on the commercial HA and the CPB were evaluated. RESULTS: The x-ray diffraction confirmed that the CPB consisted of α-tricalcium phosphate (α-TCP), CaO, and HA. The hardness, density, and α-TCP-to-HA ratio of the CPB decreased when increasing the sintering duration. Cell tests demonstrated that the CPB exhibited an earlier cell-spread response than the commercial HA. CONCLUSIONS: This study demonstrated that a phase transformation of HA into α-TCP and CaO was achieved by sintering. The cell tests indicated that the CPB has favorable in vitro cellular performance, which implied that it presented potential as bone substitute.

Exploring the biphasic dose-response effects of photobiomodulation on the viability, migration, and extracellular vesicle secretion of human adipose mesenchymal stem cells.

Photobiomodulation (PBM) is a well-established medical technology that employs diverse light sources like lasers or light-emitting diodes to generate diverse photochemical and photophysical reactions in cells, thereby producing beneficial clinical outcomes. In this study, we introduced an 830 nm near-infrared (NIR) laser irradiation system combined with a microscope objective to precisely and controllably investigate the impact of PBM on the migration and viability of human adipose mesenchymal stem cells (hADSCs). We observed a biphasic dose-response in hADSCs' viability and migration after PBM exposure (0-10 J/cm2), with the 5 J/cm2 group showing significantly higher cell viability and migration ability than other groups. Additionally, at the optimal dose of 5 J/cm2, we used nanoparticle tracking analysis (NTA) and found a 6.25-fold increase in the concentration of extracellular vesicles (EVs) derived from hADSCs (PBM/ADSC-EVs) compared to untreated cells (ADSC-EVs). Both PBM/ADSC-EVs and ADSC-EVs remained the same size, with an average diameter of 56 nm measured by the ExoView R200 system, which falls within the typical size range for exosomes. These findings demonstrate that PBM not only improves the viability and migration of hADSCs but also significantly increases the EV yield.

Effect of electrical discharging on formation of nanoporous biocompatible layer on Ti-6Al-4V alloys.

PURPOSE: In this study, the electrical discharge machining (EDM) was formed on the surface of the Ti-6Al-4V (Ti64) specimen. MATERIALS: The properties of adhesion and proliferation of MG-63 cells were evaluated the interactions between the EDM-treated layer and cells. RESULTS: The incorporation of oxygen roughened the EDM-treated specimen surface on a microscale, where the nanoscale pores were superimposed. The EDM-treated layer, which can generate the thick anatase TiO2 on the Ti64 surface, afforded a cytocompatible environment. In cell culture, alkaline phosphatase activity and osteocalcin can be dramatically enhanced on the EDM-treated surfaces when compared with the untreated surface. In addition, the increase in peak currents to the EDM functionalization led to enhancement of multiple osteoblast functions. CONCLUSIONS: This study reveals that the chemistry and crystallinity of the EDM-treated layer played important roles in affecting osteoblastic responses to the specimens, which provided insight into the development of new biomedical implant surfaces.

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.

Cancer-targeted fucoidan­iron oxide nanoparticles for synergistic chemotherapy/chemodynamic theranostics through amplification of P-selectin and oxidative stress.

A combination of chemotherapy and chemodynamic therapy (CDT) is being developed to improve the theranostic efficacy and biological safety of current therapies. However, most CDT agents are restricted due to complex issues such as multiple components, low colloidal stability, carrier-associated toxicity, insufficient reactive oxygen species generation, and poor targeting efficacy. To overcome these problems, a novel nanoplatform composed of fucoidan (Fu) and iron oxide (IO) nanoparticles (NPs) was developed to achieve chemotherapy combined with CDT synergistic treatment with a facile self-assembling manner, and the NPs were made up of Fu and IO, in which the Fu was not only used as a potential chemotherapeutic but was also designed to stabilize the IO and target P-selectin-overexpressing lung cancer cells, thereby producing oxidative stress and thus synergizing the CDT efficacy. The Fu-IO NPs exhibited a suitable diameter below 300 nm, which favored their cellular uptake by cancer cells. Microscopic and MRI data confirmed the lung cancer cellular uptake of the NPs due to active Fu targeting. Moreover, Fu-IO NPs induced efficient apoptosis of lung cancer cells, and thus offer significant anti-cancer functions by potential chemotherapeutic-CDT.

Nucleus Near-Infrared (nNIR) Irradiation of Single A549 Cells Induces DNA Damage and Activates EGFR Leading to Mitochondrial Fission.

There has been great interest in identifying the biological substrate for light-cell interaction and their relations to cancer treatment. In this study, a near-infrared (NIR) laser is focused into the nucleus (nNIR) or cytoplasm (cNIR) of a single living cell by a high numerical aperture condenser to dissect the novel role of cell nucleus in mediating NIR effects on mitochondrial dynamics of A549 non-small cell lung cancer cells. Our analysis showed that nNIR, but not cNIR, triggered mitochondrial fission in 10 min. In contrast, the fission/fusion balance of mitochondria directly exposed to cNIR does not change. While the same phenomenon is also triggered by single molecular interactions between epidermal growth factor (EGF) and its receptor EGFR, pharmacological studies with cetuximab, PD153035, and caffeine suggest EGF signaling crosstalk to DNA damaging response to mediate rapid mitochondrial fission as a result of nNIR irradiation. These results suggest that nuclear DNA integrity is a novel biological target for cellular response to NIR.

Single Cell Effects of Photobiomodulation on Mitochondrial Membrane Potential and Reactive Oxygen Species Production in Human Adipose Mesenchymal Stem Cells.

Photobiomodulation (PBM) has recently emerged in cellular therapy as a potent alternative in promoting cell proliferation, migration, and differentiation during tissue regeneration. Herein, a single-cell near-infrared (NIR) laser irradiation system (830 nm) and the image-based approaches were proposed for the investigation of the modulatory effects in mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS), and vesicle transport in single living human adipose mesenchymal stem cells (hADSCs). The irradiated-hADSCs were then stained with 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) and Rhodamine 123 (Rh123) to represent the ΔΨm and ROS production, respectively, with irradiation in the range of 2.5-10 (J/cm2), where time series of bright-field images were obtained to determine the vesicle transport phenomena. Present results showed that a fluence of 5 J/cm2 of PBM significantly enhanced the ΔΨm, ROS, and vesicle transport phenomena compared to the control group (0 J/cm2) after 30 min PBM treatment. These findings demonstrate the efficacy and use of PBM in regulating ΔΨm, ROS, and vesicle transport, which have potential in cell proliferation, migration, and differentiation in cell-based therapy.

Determining the binding mode and binding affinity constant of tyrosine kinase inhibitor PD153035 to DNA using optical tweezers.

Accurately predicting binding affinity constant (K(A)) is highly required to determine the binding energetics of the driving forces in drug-DNA interactions. Recently, PD153035, brominated anilinoquinazoline, has been reported to be not only a highly selective inhibitor of epidermal growth factor receptor but also a DNA intercalator. Here, we use a dual-trap optical tweezers to determining K(A) for PD153035, where K(A) is determined from the changes in B-form contour length (L) of PD153035-DNA complex. Here, L is fitted using a modified wormlike chain model. We found that a noticeable increment in L in 1 mM sodium cacodylate was exhibited. Furthermore, our results showed that K(A)=1.18(±0.09)×10(4) (1/M) at 23±0.5°C and the minimum distance between adjacent bound PD153035≈11 bp. We anticipate that by using this approach we can determine the complete thermodynamic profiles due to the presence of DNA intercalators.

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.

A Novel One-Pot Synthesis and Characterization of Silk Fibroin/α-Calcium Sulfate Hemihydrate for Bone Regeneration.

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 ß-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.

Ultra-High Packing Density Next Generation Microtube Array Membrane for Absorption Based Applications.

Previously, we successfully developed an extracorporeal endotoxin removal device (EERD) that is based on the novel next generation alternating microtube array membrane (MTAM-A) that was superior to the commercial equivalent. In this article, we demonstrated multiple different parameter modifications that led to multiple different types of novel new MTAM structures, which ultimately led to the formation of the MTAM-A. Contrary to the single layered MTAM, the MTAM-A series consisted of a superior packing density fiber connected in a double layered, alternating position which allowed for the greater fiber count to be packed per unit area. The respective MTAM variants were electrospun by utilizing our internally developed tri-axial electrospinning set up to produce the novel microstructures as seen in the respective MTAM variants. A key uniqueness of this study is the ability to produce self-arranged fibers into the respective MTAM variants by utilizing a single spinneret, which has not been demonstrated before. Of the MTAM variants, we observed a change in the microstructure from a single layered MTAM to the MTAM-A series when the ratio of surfactant to shell flow rate approaches 1:1.92. MTAM-A registered the greatest surface area of 2.2 times compared to the traditional single layered MTAM, with the greatest tensile strength at 1.02 ± 0.13 MPa and a maximum elongation of 57.70 ± 9.42%. The MTAM-A was selected for downstream immobilization of polymyxin B (PMB) and assembly into our own internally developed and fabricated dialyzer housing. Subsequently, the entire setup was tested with whole blood spiked with endotoxin; and benchmarked against commercial Toraymyxin fibers of the same size. The results demonstrated that the EERD based on the MTAM-A performed superior to that of the commercial equivalent, registering a rapid reduction of 73.18% of endotoxin (vs. Toraymyxin at 38.78%) at time point 15 min and a final total endotoxin removal of 89.43% (vs. Toraymyxin at 65.03%).

An Insight into Nano Silver Fluoride-Coated Silk Fibroin Bioinspired Membrane Properties for Guided Tissue Regeneration.

The current work focuses on the development of a novel electrospun silk fibroin (SF) nonwoven mat as a GTR membrane with antibacterial, biomineralization and biocompatible properties. The γ-poly glutamic acid (γ-PGA)-capped nano silver fluoride (NSF) and silver diamine fluoride (SDF) were first synthesized, which were dip-coated onto electrospun silk fibroin mats (NSF-SF and SDF-SF). UV-Vis spectroscopy and TEM depicted the formation of silver nanoparticles. NSF-SF and SDF-SF demonstrated antibacterial properties (against Porphyromonas gingivalis) with 3.1 and 6.7 folds higher relative to SF, respectively. Post-mineralization in simulated body fluid, the NSF-SF effectively promoted apatite precipitation (Ca/P ~1.67), while the SDF-SF depicted deposition of silver nanoparticles, assessed by SEM-EDS. According to the FTIR-ATR deconvolution analysis, NSF-SF portrayed ~75% estimated hydroxyapatite crystallinity index (CI), whereas pure SF and SDF-SF demonstrated ~60%. The biocompatibility of NSF-SF was ~82% when compared to the control, while SDF-coated samples revealed in vitro cytotoxicity, further needing in vivo studies for a definite conclusion. Furthermore, the NSF-SF revealed the highest tensile strength of 0.32 N/mm and 1.76% elongation at break. Therefore, it is substantiated that the novel bioactive and antibacterial NSF-SF membranes can serve as a potential candidate, shedding light on further in-depth analysis for GTR applications.

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.