The possible role of sirtuin 5 in the pathogenesis of apical periodontitis.

OBJECTIVES: We investigated the relation between expression of sirtuin 5 (SIRT5) in osteoblastic cells and progression of apical periodontitis. The role of SIRT5 in hypoxia-induced reactive oxygen species (ROS) formation and osteoblast apoptosis was also examined. MATERIALS AND METHODS: Progression of rat apical periodontitis was monitored by conventional radiography and microcomputed tomography. SIRT5 and oxidative stress biomarker 8-OHdG in bone-lining cells were assessed by immunohistochemistry. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was used to demonstrate apoptosis. In primary human osteoblasts cultured under hypoxia, Western blot was used to analyze SIRT5 expression and cleavage of pro-caspase 3 and poly(ADP-ribose) polymerase (PARP). SIRT5 was overexpressed through lentiviral technique. ROS formation and mitochondrial membrane potential changes were assessed by MitoSOX-Red and JC-1 fluorescence, respectively. Immunofluorescence microscope was used to evaluate mitochondrial release of cytochrome c. RESULTS: In rat apical periodontitis, disease progression was accompanied by decreased expression of SIRT5, increased oxidative stress, and enhanced apoptosis in bone-lining cells. SIRT5 was suppressed in cultured osteoblasts under hypoxia. SIRT5 overexpression ameliorated hypoxia-enhanced ROS formation, mitochondrial depolarization, cytochrome c leakage, activation of caspase-3, and PARP fragmentation. CONCLUSIONS: SIRT5 is able to alleviate hypoxia-enhanced osteoblast apoptosis. SIRT5 augmentation may have therapeutic potential for apical periodontitis.

Three-phase treatment concept for skeletal Class III growing patients with severe space deficiency: A report of three cases with skeletally anchored maxillary protraction.

This report provides three-phase concept for treating skeletal Class III growing patients with severe space deficiency. Three cases are presented. All had received miniplate-anchored facemask treatment and followed till near completion of growth. Infrazygomatic miniplates were used for both facemask protraction and distalization of the dentition to relieve crowding. With the aid of bone-anchored facemask, maxillary protraction may be continued independent of the orthodontic tooth movement even in late postpubertal growth peak stage. With cephalometric superimpositions using the structural method, we have demonstrated how vertical dental change could affect the skeletal changes and overall clinical outcomes. The persistent mandibular growth during pubertal growth spurt plays a main role in decreasing the effects of maxillary protraction. To keep up with the mandibular growth, we recommend using skeletally anchored facemask long-term till the end of growth spurt. Applying maxillary protraction from infrazygomatic miniplates exposed at the molar area has the merits that it avoids unwanted palatal rotation and that the miniplates maybe used as orthodontic anchorage when indicated. We emphasize the importance of planning the treatment contemplating the skeletal developmental stage and the completion of dental arches. This prolonged orthopedic treatment may contribute to greater long-term effects and stability.

Parasympathetic effect of deep pressure input on third molar extraction in adolescents.

BACKGROUD/PURPOSE: Deep pressure input is used to normalize physiological arousal due to stress. Third molar extraction is an invasive dental procedure with high stress for the patient, and an alleviation strategy is rarely applied during tooth extraction. In the present study, we investigated the effects of deep pressure input on autonomic responses during the procedures of third molar extraction in healthy adolescents. METHODS: A randomized controlled crossover design was used for adolescents who were allocated to experimental and control groups that received intervention with or without deep pressure input, respectively. Autonomic indicators, namely the heart rate, percentage of low-frequency heart rate variability (LF-HRV), percentage of high-frequency heart rate variability (HF-HRV), and low-frequency/high-frequency heart rate variability ratio (LF/HF-HRV), were assessed at the baseline, during molar extraction, and in the posttreatment phase. RESULTS: The results indicated that third molar extraction caused significant autonomic parameter changes in both groups; however, differential response patterns were observed between two groups. In particular, application of deep pressure input in the experimental group was associated with higher HF-HRV and lower LF/HF-HRV during third molar extraction compared with those in the control group. CONCLUSION: LF/HF-HRV measurement revealed balanced sympathovagal activation in response to deep pressure application. The present study suggests that the application of deep pressure alters the response of HF-HRV and facilitate maintaining sympathovagal balance during third molar extraction.

Multiplexed Detection of Tumor Markers with Multicolor Polymer Dot-Based Immunochromatography Test Strip.

There have been ongoing efforts to develop more sensitive and fast quantitative screening of cancer markers by use of fluorometric immunochromatographic test strips (ICTS) since the remarkable advances in fluorescent nanomaterials. Semiconducting polymer dots (Pdots) have recently emerged as a new type of biocompatible fluorescent probe with extraordinary brightness which is suitable for biological and clinical use. Here, we developed Pdot-based ICTS for quantitative rapid screening of prostate-specific antigen (PSA), α-fetoprotein (AFP), and carcinoembryonic antigen (CEA) in 10 min. Through use of the ultrahigh fluorescence brightness of Pdots, this immunosensor enabled much better detection sensitivity (2.05, 3.30, and 4.92 pg/mL for PSA, AFP, and CEA, respectively), in which the detection limit is at least 2 orders of magnitude lower than that of conventional fluorometric ICTS. Furthermore, we performed proof-of-concept experiments for simultaneous determination of multiple tumor markers in a single test strip. These results demonstrated that this Pdot-based ICTS platform is a promising candidate for developing new generations of point-of-care diagnostics. To the best of our knowledge, this is the first example of Pdot-based ICTS with multiplexing capability.

Effect of deep pressure input on parasympathetic system in patients with wisdom tooth surgery.

BACKGROUND/PURPOSE: Deep pressure input is used to normalize physiological arousal due to stress. Wisdom tooth surgery is an invasive dental procedure with high stress levels, and an alleviation strategy is rarely applied during extraction. In this study, we investigated the effects of deep pressure input on autonomic responses to wisdom tooth extraction in healthy adults. METHODS: A randomized, controlled, crossover design was used for dental patients who were allocated to experimental and control groups that received treatment with or without deep pressure input, respectively. Autonomic indicators, namely the heart rate (HR), percentage of low-frequency (LF) HR variability (LF-HRV), percentage of high-frequency (HF) HRV (HF-HRV), and LF/HF HRV ratio (LF/HF-HRV), were assessed at the baseline, during wisdom tooth extraction, and in the posttreatment phase. RESULTS: Wisdom tooth extraction caused significant autonomic parameter changes in both groups; however, differential response patterns were observed between the two groups. In particular, deep pressure input in the experimental group was associated with higher HF-HRV and lower LF/HF-HRV during extraction compared with those in the control group. CONCLUSION: LF/HF-HRV measurement revealed balanced sympathovagal activation in response to deep pressure application. The results suggest that the application of deep pressure alters the response of HF-HRV and facilitates maintaining sympathovagal balance during wisdom tooth extraction.

Squaraine-based polymer dots with narrow, bright near-infrared fluorescence for biological applications.

This article describes the design and development of squaraine-based semiconducting polymer dots (Pdots) that show large Stokes shifts and narrow-band emissions in the near-infrared (NIR) region. Fluorescent copolymers containing fluorene and squaraine units were synthesized and used as precursors for preparing the Pdots, where exciton diffusion and likely through-bond energy transfer led to highly bright and narrow-band NIR emissions. The resulting Pdots exhibit the emission full width at half-maximum of ∼36 nm, which is ∼2 times narrower than those of inorganic quantum dots in the same wavelength region (∼66 nm for Qdot705). The squaraine-based Pdots show a high fluorescence quantum yield (QY) of 0.30 and a large Stokes shift of ∼340 nm. Single-particle analysis indicates that the average per-particle brightness of the Pdots is ∼6 times higher than that of Qdot705. We demonstrate bioconjugation of the squaraine Pdots and employ the Pdot bioconjugates in flow cytometry and cellular imaging applications. Our results suggest that the narrow bandwidth, high QY, and large Stokes shift are promising for multiplexed biological detections.

Dual colorimetric and fluorescent sensor based on semiconducting polymer dots for ratiometric detection of lead ions in living cells.

Recently, semiconducting polymer dots (Pdots) have become a novel type of ultrabright fluorescent probes which hold great promise in biological imaging and analytical detection. Here we developed a visual sensor based on Pdots for Pb(2+) detection. We first embedded near-infrared (NIR) dyes into the matrix of poly[(9,9-dioctylfluorene)-co-2,1,3-benzothiadiazole-co-4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole] (PFBT-DBT) polymer and then capped the Pdots with polydiacetylenes (PDAs), in which parts of the PDAs were prefunctionalized with 15-crown-5 moieties to form Pdots. The high selectivity of these Pdots for lead ions is attributed to the formation of 2:1 15-crown-5-Pb(2+)-carboxylate sandwich complex on the Pdot surface. After Pb(2+) chelation, the conjugation system of the PDA was perturbed and strained, causing a chromatic change of the PDA from blue to red. At the same time, the encapsulated NIR dyes were liable to leach out that resulted in an emission variation of the Pdots. Accordingly, lead ions can be recognized by either color change or emission variation of the Pdots. We also loaded these nanoprobes into live HeLa cells through endocytosis, and then monitored changes in Pb(2+) levels within cells, demonstrating their utility for use in cellular and bioimaging applications. In addition, we fabricated easy-to-prepare test strips impregnated with Pdot-poly(vinyl alcohol) films to identify Pb(2+) in real samples, which proved their applicability for in situ on-site detection. Our results suggest that this Pdot-based visual sensor shows promising potential for advanced environmental and biological applications.

Polydiacetylene-enclosed near-infrared fluorescent semiconducting polymer dots for bioimaging and sensing.

Semiconducting polymer dots (P-dots) recently have emerged as a new type of ultrabright fluorescent probe with promising applications in biological imaging and detection. With the increasing desire for near-infrared (NIR) fluorescing probes for in vivo biological measurements, the currently available NIR-emitting P-dots are very limited and the leaching of the encapsulated dyes/polymers has usually been a concern. To address this challenge, we first embedded the NIR dyes into the matrix of poly[(9,9-dioctylfluorene)-co-2,1,3-benzothiadiazole-co-4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole] (PF-BT-DBT) polymer and then enclosed the doped P-dots with polydiacetylenes (PDAs) to avoid potential leakage of the entrapped NIR dyes from the P-dot matrix. These PDA-enclosed NIR-emitting P-dots not only emitted much stronger NIR fluorescence than conventional organic molecules but also exhibited enhanced photostability over CdTe quantum dots, free NIR dyes, and gold nanoclusters. We next conjugated biomolecules onto the surface of the resulting P-dots and demonstrated their capability for specific cellular labeling without any noticeable nonspecific binding. To employ this new class of material as a facile sensing platform, an easy-to-prepare test paper, obtained by soaking the paper into the PDA-enclosed NIR-emitting P-dot solution, was used to sense external stimuli such as ions, temperature, or pH, depending on the surface functionalization of PDAs. We believe these PDA-coated NIR-fluorescing P-dots will be very useful in a variety of bioimaging and analytical applications.

Physiologic and behavioral effects of papoose board on anxiety in dental patients with special needs.

BACKGROUND/PURPOSE: Anxiety induced by dental treatment can become a serious problem, especially for patients with special needs. Application of deep touch pressure, which is a sensory adaptation technique, may ameliorate anxiety in disabled patients. However, few empiric studies have investigated the possible links between the clinical effects of deep touch pressure and its behavioral and physiologic aspects. Equally little progress has been made concerning theoretical development. The current study is a crossover intervention trial to investigate the behavioral and physiological effects of deep touch pressure for participants receiving dental treatment. METHODS: Nineteen disabled participants, who were retrospectively subclassified for positive trend or negative trend, were recruited to receive the papoose board as an application of deep touch pressure. Quantitative analyses of behavioral assessments and physiological measurements, including electrodermal activity and heart rate variability, were conducted. We sought to understand the modulation of the autonomic nervous system and the orchestration of sympathetic and parasympathetic (PsNS) nervous systems. RESULTS: Behavioral assessments reported that higher levels of anxiety were induced by the dental treatment for participants with both groups of positive and negative trends. Although no significant differences were found in the SNS activity, physiologic responses indicated that significantly changes of PsNS activity were observed under the stress condition (dental treatment) when deep touch pressure intervention was applied, especially for participants in the group of positive trend. CONCLUSION: Our results suggest that the PsNS activation plays a critical role in the process of ANS modulation. This study provides not only physiologic evidence for the modulation effects of deep touch pressure on stressful conditions in dental environments but also the evidence that the application of papoose board, as a sensory adaptation technique, is not harmful for dental patients with special needs.

Ultrabright Dibenzofluoran-Based Polymer Dots with NIR-IIa Emission Maxima and Unusual Large Stokes Shifts for 3D Rotational Stereo Imaging.

Emerging organic molecules with emissions in the second near-infrared (NIR-II) region are garnering significant attention. Unfortunately, achieving accountable organic emission intensity over the NIR-IIa (1300 nm) region faces challenges due to the intrinsic energy gap law. Up to the current stage, all reported organic NIR-IIa emitters belong to polymethine-based dyes with small Stokes shifts (<50 nm) and low quantum yield (QY; ≤0.015%). However, such polymethines have proved to cause self-absorption with constrained emission brightness, limiting advanced development in deep-tissue imaging. Here a new NIR-IIa scaffold based on rigid and highly conjugated dibenzofluoran core terminated by amino-containing moieties that reveal emission peaks of 1230-1305 nm is designed. The QY is at least 10 times higher than all synthesized or reported NIR-IIa polymethines with extraordinarily large Stokes shifts of 370-446 nm. DBF-BJ is further prepared as a polymer dot to demonstrate its in vivo 3D stereo imaging of mouse vasculature with a 1400 nm long-pass filter.

Effect of carbon spacer length on the antibacterial properties of zwitterionic poly(sulfobetaine) type copolymeric brushes and their application in wound healing.

Creating infection resistant polymer brushes possessing antiadhesive, bactericidal and cell-compatible features can be regarded as a promising approach to prevent biomaterial-associated infections. In this work, polysulfobetaine type zwitterionic homo- and copolymer brushes with varying spacer lengths (charge separation distance between zwitterions, n = 3, 6 or 12) were allowed to grow onto a tartaric acid based aliphatic polyester substrate using surface initiated atom transfer radical polymerization. All of the brush modified surfaces were thoroughly characterized and assessed for their anti-infective performances in vitro. Strikingly, a suitable copolymer composition, i.e., polyZ6-co-Z12 (50/50 copolymer of polysulfobetaine methacrylates with 6 and 12 spacer lengths), was observed to inhibit bacterial growth completely and its activity was sustained for a long time (>3 months). Surprisingly, its antibacterial effect was found to be bactericidal, as is evident from live-dead staining of residual dead bacterial cells that can be easily released by exposing the surface to salt solution, thereby regenerating the surface. However, all of the other copolymer as well as homopolymer brushes exhibited bacteriostatic behavior. An attempt was made to understand the peculiar behavior of this particular brush composition. Nevertheless, the biocidal and also protein repellent brush did not display any cytotoxicity towards human cells, making it an ideal substrate to be used as an infection resistant biomedical implant. Animal studies further confirmed that this particular copolymeric brush modified scaffold can be a promising anti-infective wound dressing material with rapid wound healing effects as compared to the unmodified scaffold.

Hybrid polymer dot-magnetic nanoparticle based immunoassay for dual-mode multiplexed detection of two mycotoxins.

We designed polymer dot-magnetic nanoparticle nanohybrids for signal enhancement in a test strip platform. Besides, the multicolor emissions of the Pdots embed multiplexing ability for this test strip. Two mycotoxins, aflatoxin B1 and zearalenone, were tested with the determined limits of detection of 2.15 ng mL-1 and 4.87 ng mL-1, respectively.

Metformin Reduces Bone Resorption in Apical Periodontitis Through Regulation of Osteoblast and Osteoclast Differentiation.

INTRODUCTION: We have previously demonstrated that auxiliary metformin therapy promotes healing of apical periodontitis. Here we aimed to investigate the effects of metformin on osteoblast differentiation and osteoclast formation in cultured cells and rat apical periodontitis. METHODS: Murine pre-osteoblasts MC3T3-E1 and macrophages RAW264.7 were cultured under hypoxia (2% oxygen) or normoxia (21% oxygen) and stimulated with receptor activator of nuclear factor-κB ligand (RANKL) when indicated. Metformin was added to the cultures to evaluate its anti-hypoxic effects. Expressions of osteoblast differentiation regulator runt-related transcription factor 2 (RUNX2), RANKL, and osteoclast marker tartrate-resistant acid phosphatase (TRAP) were assessed by Western blot. Apical periodontitis was induced in mandibular first molars of 10 Sprague-Dawley rats. Root canal therapy with or without metformin supplement was performed. Periapical bone resorption was measured by micro-computed tomography. Immunohistochemistry was used to examine RUNX2, RANKL, and TRAP expressions. RESULTS: Hypoxia suppressed RUNX2 expression and enhanced RANKL synthesis in pre-osteoblasts. TRAP production increased in macrophages after hypoxia and/or RANKL stimulation. Metformin reversed hypoxia-induced RUNX2 suppression and RANKL synthesis in pre-osteoblasts. Metformin also inhibited hypoxia and RANKL-enhanced TRAP synthesis in macrophages. Intracanal metformin diminished bone loss in rat apical periodontitis. Comparing with vehicle control, cells lining bone surfaces in metformin-treated lesions had significantly stronger expression of RUNX2 and decreased synthesis of RANKL and TRAP. CONCLUSIONS: Alleviation of bone resorption by intracanal metformin was associated with enhanced osteoblast differentiation and diminished osteoclast formation in rat apical periodontitis. Our results endorsed the role of metformin as an effective medicament for inflammatory bone diseases.

Hybrid semiconducting polymer dot-quantum dot with narrow-band emission, near-infrared fluorescence, and high brightness.

This communication describes a new class of semiconducting polymer nanoparticle-quantum dot hybrid with high brightness, narrow emission, near-IR fluorescence, and excellent cellular targeting capability. Using this approach, we circumvented the current difficulty with obtaining narrow-band-emitting and near-IR-fluorescing semiconducting polymer nanoparticles while combining the advantages of both semiconducting polymer nanoparticles and quantum dots. We further demonstrated the use of this new class of hybrid nanomaterial for effective and specific cellular and subcellular labeling without any noticeable nonspecific binding. This hybrid nanomaterial is anticipated to find use in a variety of in vitro and in vivo biological applications.

Reversible photoswitching of spiropyran-conjugated semiconducting polymer dots.

Semiconducting polymer dots (Pdots) recently have emerged as a new class of ultrabright fluorescent probes with promising applications in biological detection and imaging. We developed photoswitchable Pdots by conjugating photochromic spiropyran molecules onto poly[9,9-dioctylfluorenyl-2,7-diyl)-co-1,4-benzo-{2,1'-3}-thiadiazole)] (PFBT). The modulation of fluorescence was achieved by ultraviolet irradiation, which converted spiropyran into its visible-absorbing merocyanine form. The merocyanine efficiently quenched the fluorescence of PFBT via Förster resonance energy transfer (FRET). We then reversed the quenching by subsequent irradiation with visible light to get back the fluorescence of PFBT. This FRET-based photomodulation of Pdot fluorescence could be repeated multiple times. We next conjugated biomolecules onto the surface of these photoswitchable Pdots and demonstrated their specific cellular and subcellular labeling to different types of cells without any noticeable nonspecific binding. We anticipate these photoswitchable and biocompatible Pdots will be useful in developing bioimaging techniques in the future.

Self-healable and anti-freezing ion conducting hydrogel-based artificial bioelectronic tongue sensing toward astringent and bitter tastes.

Numerous efforts have been attempted to mimic human tongue since years. However, they still have limitations because of damages, temperature effects, detection ranges etc. Herein, a self-healable hydrogel-based artificial bioelectronic tongue (E-tongue) containing mucin as a secreted protein, sodium chloride as an ion transporting electrolyte, and chitosan/poly(acrylamide-co-acrylic acid) as the main 3D structure holding hydrogel network is synthesized. This E-tongue is introduced to mimic astringent and bitter mouth feel based on cyclic voltammetry (CV) measurements subjected to target substances, which permits astringent tannic acid (TA) and bitter quinine sulfate (QS) to be detected over wide corresponding ranges of 29.3 mM-0.59 µM and 63.8 mM-6.38 µM with remarkable respective sensitivities of 0.2 and 0.12 wt%-1. Besides, the taste selectivity of this E-tongue is performed in the presence of various mixed-taste chemicals to show its high selective behavior toward bitter and astringent chemicals. The electrical self-healability is shown via CV responses to illustrate electrical recovery within a short time span. In addition, cytotoxicity tests using HeLa cells are performed, where a clear viability of ≥95% verified its biocompatibility. The anti-freezing sensing of E-tongue tastes at -5 °C also makes this work to be useful at sub-zero environments. Real time degrees of tastes are detected using beverages and fruits to confirm future potential applications in food taste detections and humanoid robots.

Development of Stereo NIR-II Fluorescence Imaging System for 3D Tumor Vasculature in Small Animals.

Near-infrared-II (NIR-II, 1000-1700 nm) fluorescence imaging boasts high spatial resolution and deep tissue penetration due to low light scattering, reduced photon absorption, and low tissue autofluorescence. NIR-II biological imaging is applied mainly in the noninvasive visualization of blood vessels and tumors in deep tissue. In the study, a stereo NIR-II fluorescence imaging system was developed for acquiring three-dimension (3D) images on tumor vasculature in real-time, on top of the development of fluorescent semiconducting polymer dots (IR-TPE Pdots) with ultra-bright NIR-II fluorescence (1000-1400 nm) and high stability to perform long-term fluorescence imaging. The NIR-II imaging system only consists of one InGaAs camera and a moving stage to simulate left-eye view and right-eye view for the construction of 3D in-depth blood vessel images. The system was validated with blood vessel phantom of tumor-bearing mice and was applied successfully in obtaining 3D blood vessel images with 0.6 mm- and 5 mm-depth resolution and 0.15 mm spatial resolution. The NIR-II stereo vision provides precise 3D information on the tumor microenvironment and blood vessel path.

Ratiometric temperature sensing with semiconducting polymer dots.

This communication describes ultrabright single-nanoparticle ratiometric temperature sensors based on semiconducting polymer dots (Pdots). We attached the temperature sensitive dye-Rhodamine B (RhB), whose emission intensity decreases with increasing temperature-within the matrix of Pdots. The as-prepared Pdot-RhB nanoparticle showed excellent temperature sensitivity and high brightness because it took advantage of the light harvesting and amplified energy transfer capability of Pdots. More importantly, the Pdot-RhB nanoparticle showed ratiometric temperature sensing under a single wavelength excitation and has a linear temperature sensing range that matches well with the physiologically relevant temperatures. We employed Pdot-RhB for measuring intracellular temperatures in a live-cell imaging mode. The exceptional brightness of Pdot-RhB allows this nanoscale temperature sensor to be used also as a fluorescent probe for cellular imaging.

Development of ultrabright semiconducting polymer dots for ratiometric pH sensing.

Semiconducting polymer-based nanoparticles (Pdots) have recently emerged as a new class of ultrabright probes for biological detection and imaging. This paper describes the development of poly(2,5-di(3',7'-dimethyloctyl)phenylene-1,4-ethynylene) (PPE) Pdots as a platform for designing Förster resonance energy transfer (FRET)-based ratiometric pH nanoprobes. We describe and compare three routes for coupling the pH-sensitive dye, fluorescein, to PPE Pdots, which is a pH-insensitive semiconducting polymer. This approach offers a rapid and robust sensor for pH determination using the ratiometric methodology where excitation at a single wavelength results in two emission peaks, one that is pH sensitive and the other one that is pH insensitive for use as an internal reference. The linear range for pH sensing of the fluorescein-coupled Pdots is between pH 5.0 and 8.0, which is suitable for most cellular studies. The pH-sensitive Pdots show excellent reversibility and stability in pH measurements. In this paper, we use them to measure the intracellular pH in HeLa cells following their uptake by endocytosis, thus demonstrating their utility for use in cellular and imaging experiments.