An Ultraflexible and Stretchable Aptameric Graphene Nanosensor for Biomarker Detection and Monitoring.

An ultraflexible and stretchable field-effect transistor nanosensor is presented that uses aptamer-functionalized monolayer graphene as the conducting channel. Specific binding of the aptamer with the target biomarker induces a change in the carrier concentration of the graphene, which is measured to determine the biomarker concentration. Based on a Mylar substrate that is only 2.5-µm thick, the nanosensor is capable of conforming to underlying surfaces (e.g., those of human tissue or skin) that undergo large bending, twisting, and stretching deformations. In experimental testing, the device is rolled on cylindrical surfaces with radii down to 40 µm, twisted by angles ranging from -180° to 180°, or stretched by extensions up to 125%. With these large deformations applied either cyclically or non-recurrently, the device is shown to incur no visible mechanical damage, maintain consistent electrical properties, and allow detection of TNF-α, an inflammatory cytokine biomarker, with consistently high selectivity and low limit of detection (down to 5 × 10-12M). The nanosensor can thus potentially enable consistent and reliable detection of liquid-borne biomarkers on human skin or tissue surfaces that undergo large mechanical deformations.

Design and Fabrication of a Three-Dimensional Multi-Electrode Array for Neuron Electrophysiology.

Neural recording and stimulation with high spatial and temporal resolution are highly desirable in the study of neurocommunication and diseases. Planar multiple microelectrode arrays (MEA) or quasi-three-dimensional (3D) MEA with fixed height have been proposed by many researchers and become commercially available. In this paper, we present the design, fabrication, and test of a novel true 3D multiple electrode array for brain slice stimulation and recording. This MEA is composed of 105 microelectrodes with 50 µm diameter and 125 µm center-to-center spacing integrated in a 1.2 × 1.2 mm2 area. This "true" 3D MEA allows us to precisely position the individual electrodes by piezoelectric-based actuators to penetrate the inactive tissue layer and to approach the active neurons so as to optimize the recording and stimulation of electrical field potential. The capability to stimulate nerve fibers and record postsynaptic field potentials was demonstrated in an experiment using mouse brain hippocampus slice.

Influence of magnetic field on gluten aggregation behavior and quality characteristics of dough enriched with potato pulp.

This study investigated the effect of varying magnetic field intensities (ranging from 0 to 10 mT) on the quality characteristics of dough with 40 % potato pulp substitution (DPP). The results indicated that the DPP fermented with a 4 mT magnetic field exhibited a significant enhancement in the combination of water and substrate, thereby elevating the viscoelastic properties of DPP through reinforcing the stability of gluten network. Meanwhile, DPP treated with a 4 mT magnetic field exhibited the highest amount of disulfide bonds (11.64 µmol SS/g sample). This is accompanied by a prominent cross-linkage structure, as evidenced by SDS-PAGE and CLSM. Notably, the application of a magnetic field substantially augments the dough's capacity to retain gas during fermentation. In addition, the application of magnetic field significantly increased the wet gluten content (20.85 %, P < 0.05) in DPP, which improved tensile properties and an acceptable color profile. The introduction of a magnetic field induces gluten aggregation, which in turn results in heightened particle size distribution and ζ-potential values. In conclusion, this study emphasize the potential of magnetic field technology as a viable method to enhance the overall quality attributes of dough enriched with potato pulp substitution.

Surface acoustic wave-assisted microfluidic isolation of aptamers.

Aptamers are synthetic single-stranded nucleic acid molecules that bind to biochemical targets with high affinity and specificity. The method of systematic evolution of ligands by exponential enrichment (SELEX) is widely used to isolate aptamers from randomized oligonucleotides. Recently, microfluidic technology has been applied to improve the efficiency and reduce the cost in SELEX processes. In this work, we present an approach that exploits surface acoustic waves to improve the affinity selection process in microfluidic SELEX. Acoustic streaming is used to enhance the interactions of the solution-based oligonucleotide molecules with microbead-immobilized target molecules, allowing the identification of high-affinity aptamer candidates in a more efficient manner. For demonstration, a DNA aptamer is isolated within three rounds of selection in 5 h to specifically bind to immunoglobulin E, a representative target protein, with an equilibrium dissociation constant of approximately 22.6 nM.

A Hydrogel-Based Self-Sensing Underwater Actuator.

Soft robots made of hydrogels are suited for underwater exploration due to their biocompatibility and compliancy. Yet, reaching high dexterity and actuation force for hydrogel-based actuators is challenging. Meanwhile, real-time proprioception is critical for feedback control. Moreover, sensor integration to mimic living organisms remains problematic. To address these challenges, we introduce a hydrogel actuator driven by hydraulic force with a fast response (time constant 0.83 s). The highly stretchable and conductive hydrogel (1400% strain) is molded into the PneuNet shape, and two of them are further assembled symmetrically to actuate bi-directionally. Then, we demonstrate its bionic application for underwater swimming, showing 2 cm/s (0.19 BL/s) speed. Inspired by biological neuromuscular systems' sensory motion, which unifies the sensing and actuation in a single unit, we explore the hydrogel actuator's self-sensing capacity utilizing strain-induced resistance change. The results show that the soft actuator's proprioception can monitor the undulation in real-time with a sensitivity of 0.2%/degree. Furthermore, we take a finite-element method and first-order differential equations to model the actuator's bending in response to pressure. We show that such a model can precisely predict the robot's bending response over a range of pressures. With the self-sensing actuator and the proposed model, we expect the new approach can lead to future soft robots for underwater exploration with feedback control, and the underlying mechanism of the undulation control might offer significant insights for biomimetic research.

A High-Throughput MEMS-Based Differential Scanning Calorimeter for Direct Thermal Characterization of Antibodies.

Calorimeters, which can be used for rapid thermal characterization of biomolecules, are getting intense attention in drug development. This paper presents a novel MEMS-based differential scanning calorimeter (DSC) for direct thermal characterization of protein samples. The DSC consisted of a pair of temperature sensors made by vanadium oxide (VOx) film with a temperature coefficient of resistivity of -0.025/K at 300 K, a microfluidic device with high thermal insulation (2.8 K/mW), and a Peltier heater for linear temperature scanning. The DSC exhibited high sensitivity (6.1 µV/µW), low noise (0.4 µW), high scanning rate (45 K/min), and low sample consumption volume (0.63 µL). The MEMS DSC was verified by measuring the temperature-induced denaturation of lysozyme at different pH, and then used to study the thermal stability of a monoclonal antibody (mAb), an antigen-binding fragment (Fab), and a dual variable domain immunoglobulin (DVD-Ig) at pH = 6. The results showed that lysozyme is a stable protein in the pH range of 4.0-8.0. The protein stability study revealed that the transition temperatures of the intact Fab fragment, mAb, and DVD proteins were comparable with conformational stability results obtained using conventional commercial DSC. These studies demonstrated that the MEMS DSC is an effective tool for directly understanding the thermal stability of antibodies in a high-throughput and low-cost manner compared to conventional calorimeters.

Towards detection of biomarkers in the eye using an aptamer-based graphene affinity nanobiosensor.

We present an approach to enable the sensitive and specific detection of biomarkers in undiluted tears in the eye using an aptamer-based graphene affinity nanosensor. The nanosensor is a graphene field-effect transistor, in which a nucleic acid aptamer and a biomolecule-permeable polyethylene glycol (PEG) nanolayer are immobilized on the graphene surface. The aptamer is capable of specifically recognize the target biomarker and induce a change in the carrier concentration of the graphene, which is measured to determine the biomarker concentration. The PEG nanolayer minimizes nonspecific adsorption of background molecules in the sample that would otherwise interfere with the biomarker detection. Experimental results show that tumor necrosis factor alpha (TNF-alpha), an inflammatory cytokine, can be sensitively and specifically detected in undiluted artificial tears with a limit of detection of 0.34 pM. This ability to detect and measure biomarkers in undiluted physiological fluids allows the nanosensor to be potentially used in applications where sample dilutions are not practical, such as wearable measurements of tear-borne biomarkers in the eye.

Nanocalorimeters for biomolecular analysis and cell metabolism monitoring.

Nanocalorimeters, or microfabricated calorimeters, provide a promising way to characterize the thermal process of biological processes, such as biomolecule interactions and cellular metabolic activities. They enabled miniaturized heat measurement onto a chip device with potential benefits including low sample consumption, low cost, portability, and high throughput. Over the past few decades, researchers have tried to improve nanocalorimeters' performance, in terms of sensitivity, accuracy, and detection resolution, by exploring different sensing methods, thermal insulation techniques, and liquid handling methods. The enhanced devices resulted in new applications in recent years, and here we have summarized the performance parameters and applications based on categories. Finally, we have listed the current technical difficulties in nanocalorimeter research and hope for future solutions to overcome them.

A Wearable and Deformable Graphene-Based Affinity Nanosensor for Monitoring of Cytokines in Biofluids.

A wearable and deformable graphene-based field-effect transistor biosensor is presented that uses aptamer-modified graphene as the conducting channel, which is capable of the sensitive, consistent and time-resolved detection of cytokines in human biofluids. Based on an ultrathin substrate, the biosensor offers a high level of mechanical durability and consistent sensing responses, while conforming to non-planar surfaces such as the human body and withstanding large deformations (e.g., bending and stretching). Moreover, a nonionic surfactant is employed to minimize the nonspecific adsorption of the biosensor, hence enabling cytokine detection (TNF-α and IFN-γ, significant inflammatory cytokines, are used as representatives) in artificial tears (used as a biofluid representative). The experimental results demonstrate that the biosensor very consistently and sensitively detects TNF-α and IFN-γ, with limits of detection down to 2.75 and 2.89 pM, respectively. The biosensor, which undergoes large deformations, can thus potentially provide a consistent and sensitive detection of cytokines in the human body.

A novel mutation in the SH3BP2 gene causes cherubism: case report.

BACKGROUND: Cherubism is a rare hereditary multi-cystic disease of the jaws, characterized by its typical appearance in early childhood, and stabilization and remission after puberty. It is genetically transmitted in an autosomal dominant fashion and the gene coding for SH3-binding protein 2 (SH3BP2) may be involved. CASE PRESENTATION: We investigated a family consisting of 21 members with 3 female affected individuals with cherubism from Northern China. Of these 21 family members, 17 were recruited for the genetic analysis. We conducted the direct sequence analysis of the SH3BP2 gene among these 17 family members. A disease-causing mutation was identified in exon 9 of the gene. It was an A1517G base change, which leads to a D419G amino acid substitution. CONCLUSION: To our knowledge, the A1517G mutation has not been reported previously in cherubism. This finding is novel.

[Effect of extracellular zinc on osteoclastic resorption in dental mineralized tissues].

OBJECTIVE: To investigate the bone resorption caused by osteoclasts and modulating functions of zinc ion on dental slices. METHODS: Osteoclasts were separated from long-limb bones of neonatal rabbits, cultured with de-activated human tooth slices and glass slices. The cells in the experiment group were treated with 1x10(-14)mol/L-1x10(-4)mol/L zinc+10% (volume fraction) fetal calf serum (FCS)+alphaMEM, while those in the control group were grown in 10%FCS+alphaMEM. Osteoclasts on glass slices were stained by TRAP staining. The absorption pits on tooth slices were observed by inverted phase contrast microscope. The resorbing activity was evaluated with the concentration of calcium in the supernatant liquid of osteoclasts. The ratio between the concentration of calcium in the experiment group and that of the control group was termed the resorption index. RESULTS: The isolated cells were multinuclear and showed positive in cytoplasma by TRAP staining. Usually, osteoclasts resorbed tooth slices first on the cementum and dentin, which had lower content of mineralized tissue. Compared with those on bone slices, the lacunae on the dental slices appeared less in amount, less in area and shallower in depth. They often showed shallow pits in a large area. Microscopy showed that the number and area of absorption pits formed on treated tissues were less than those on the control tissues. The content of calcium in the supernatant liquid increased at the concentrations of 1x10(-4)-1x10(-14)mol/L zinc, especially in the group of 1x10(-8)mol/L, 1x10(-10) mol/L, 1x10(-14)mol/L zinc on the 3rd day (P<0.05). But they were reversed on the 7th day, except in the group of 1x10(-14)mol/L zinc. At the end of culture, the resorption indexes of 1x10(-4)-1x10(-7)mol/L, 1x10(-9)mol/L, 1x10(-12)mol/L and 1x10(-13)mol/L group were lower than 1, but those of 1x10(-8)mol/L, 1x10(-10)mol/L, 1x10(-11)mol/L and 1x10(-14)mol/L group were higher than 1. CONCLUSION: The effect of zinc ion on osteoclastic resorption in dental slices is associated with phase and dosage closely.

Micro-differential scanning calorimeter for liquid biological samples.

We developed an ultrasensitive micro-DSC (differential scanning calorimeter) for liquid protein sample characterization. This design integrated vanadium oxide thermistors and flexible polymer substrates with microfluidics chambers to achieve a high sensitivity (6 V/W), low thermal conductivity (0.7 mW/K), high power resolutions (40 nW), and well-defined liquid volume (1 µl) calorimeter sensor in a compact and cost-effective way. We further demonstrated the performance of the sensor with lysozyme unfolding. The measured transition temperature and enthalpy change were in accordance with the previous literature data. This micro-DSC could potentially raise the prospect of high-throughput biochemical measurement by parallel operation with miniaturized sample consumption.

Characteristics of benign lymphoadenosis of oral mucosa.

AIM: To investigate the pathological characteristics and carcinogenesis mechanism of benign lymphoadenosis of oral mucosa (BLOM). METHODS: The expressions of Ki-67, CD34 and apoptosis were evaluated by immunohistochemical SP staining in 64 paraffin-embedded tissue samples. Of them, 9 were from BLOM with dysplasia, 15 from BLOM without dysplasia, 15 from oral squamous cell carcinoma (OSCC), 15 from oral precancerosis, and 10 from normal tissues. Cell proliferation, apoptosis and angiogenesis of tissue samples were also analyzed. RESULTS: The expression of Ki-67 in BLOM with dysplasia, oral precancerosis and OSCC was significantly higher than in BLOM without dysplasia and normal mucosa. The microvascular density (MVD) in BLOM with and without dysplasia, oral precancerosis, and OSCC was significantly higher than in normal mucosa. Apoptosis in BLOM and oral precancerosis was significantly higher than in OSCC and normal mucosa. CONCLUSION: Benign lymphoadenosis of oral mucosa has potentialities of cancerization.

[Comparison of two methods of isolation and culture of osteoclasts and the dynamic observation of bone resorption].

OBJECTIVE: To study the origin, morphological structure, and functional regulation of osteoclast (OC) for further investigation on the mechanism and regulation of bone resorption. METHODS: The OCs were isolated by two kinds of traditional method. Osteoclasts were isoclated from neonatal rat long bones. The cytochemistry was observed. The osteoclast-like cells (OLC) were derived from the mouse bone marrow cells in the presence of 1,25(OH)2VitD3 in vitro. RESULTS: Both morphological and functional studies showed that the isolated cells shared some of the typical characteristics of osteoclasts, that is A. multinuclearity; B. developing spreading and pseudopodial activity when cultured on glass; C. high tartrate-resistant acid phosphatase (TRAP); D. resorption lacunae could be found when the cells were cocultured with devitalized bone slices and the number was increased as the time followed. OLC had the same histological and structural traits as the OCs by the former method. The concentration of Ca(2+) and acid phosphatase (ACP) increased gradually. CONCLUSION: Different kinds of method fit different experiments. The OC obtained by the first method has more activity of bone resorption. The OLC by the second method has more in quantity and can be used in the study of cell differentiation.

[Expression of macrophage inflammatory protein-1alpha, a disintegrin-like and metalloproteinase 8 and 12, and CD68 protein in giant cell lesions of jaw and giant cell tumors of long bone].

OBJECTIVE: To detect the expression of macrophage inflammatory protein-1alpha (MIP-1alpha), a disintegrin-like and metalloproteinase (ADAM) 8 and 12 and CD68 protein in giant cell lesions of jaw and giant cell tumors of long bone, and to study their effects on the histogenesis of giant cells in such lesions. METHODS: MIP-1alpha, ADAM8, ADAM12 and CD68 were detected by immunohistochemistry in 24 paraffin-embedded specimens of central giant cell lesions of jaw and giant cell tumors respectively. RESULTS: MIP-1alpha positive signal was located in blood vessels and bone. ADAM8, ADAM12 and CD68 positive signals were located in the cell membrane and cytoplasm of all multinucleated giant cells and some round mononuclear cells in the lesions. In addition, some spindle mononuclear stromal cells were positive for ADAM12 in both lesions. CONCLUSION: Multinucleated giant cells probably originate from CD68-postive round mononuclear cells, which are recruited from monocyte-macrophage system by chemokines, such as MIP-1alpha, followed by cell fusion mediated by ADAM8 and ADAM12.

Clinicopathologic spectrum of the so-called calcifying odontogenic cysts: a study of 21 intraosseous cases with reconsideration of the terminology and classification.

The so-called calcifying odontogenic cyst (COC) represents a heterogeneous group of lesions that exhibit a variety of clinicopathologic and behavioral features. Because of this diversity, there has been confusion and disagreement on the terminology and classification of these lesions. We reviewed the clinicopathologic features of 21 intraosseous cases that were previously diagnosed as COC or under related diagnostic terms. Based on the biologic behavior, the lesions of the present series were divided into three subgroups: cyst, benign tumor, and malignant tumor. Sixteen cases (nine men and seven women) proved to be unicystic lesions with (five cases) or without associated odontoma. The lining epithelium of the cystic lesions fulfilled the histologic criteria for COC proposed by the World Health Organization, and their overall clinicopathologic features were consistent with that of developmental odontogenic cysts. The age of patients from the cyst group peaked at the second decade. The maxilla was affected more often (69%) than the mandible, with a predilection for the canine-premolar region (62.5%). Thirteen patients with follow-up information revealed no recurrence following enucleation. The four cases in the benign tumor group had variable clinicopathologic features. Two cases were solid tumors consisting of ameloblastoma-like sheets of odontogenic epithelium that contained ghost cells/calcification foci and juxtaepithelial dentinoid. Both patients experienced multiple recurrences following conservative surgeries. The other two lesions contained typical areas of COC and other types of odontogenic tumors (one ameloblastoma and one odontogenic myxofibroma). All four lesions occurred in the mandible and were relatively large. In the present series one case identified as malignant tumor arose from a previously benign COC. The tumor shared some features of COC (ghost cell foci and dystrophic calcification) but also had prominent mitotic activity, nuclear and cytoplasmic pleomorphism, areas of tumor necrosis, and infiltrative/destructive growth. Recognizing the extreme diversity in clinicopathologic features and biologic behavior among the so-called COCs, we suggest that the term COC should be used to specifically designate the unicystic lesions with or without an associated odontoma, i.e., lesions of the cyst group, and other related lesions identified as benign tumor and malignant tumor should be termed and classified separately. A tentative scheme with respect to the terminology and classification for this group of disparately behaving lesions was herein proposed to reflect the likely difference of their nature.

[Effect of puerarin on the bone metabolism in vitro].

OBJECTIVE: To study the effect of puerarin on the bone formation and the bone resorption in vitro. METHODS: The osteoblasts (OBs) were obtained from the rat calvaria. The osteoclasts (OCs) were isolated by the methods according Chambers' and Yu Shifeng's. The cells in the experiment group were grown in 10% fetal calf serum (FCS) + alpha MEM + various concentrations of puerarin. The control groups were grown in 10% FCS + alpha MEM. The growth of OBs was assessed by MTT method. The differentiation of OBs was examined by the ALP activity. The OCs were observed by the TRAP stain. The area of bone resorption and the concentration of Ca2+ in the supernatant liquid of OCs cultures were also tested. RESULTS: Puerarin had no effect on the growth of the OBs, but it could stimulate the formation and the secretion of alkaline phosphatase (ALP). The OCs vacuolarized under the effect of puerarin. The area of bone resorption and the concentration of Ca2+ in the supernatant liquid of OCs cultures were both decreased. CONCLUSION: Puerarin can suppress the bone resorption and promote the bone formation, but the former effect is stronger than the latter.

[Purification and study of the characteristics of the multinucleated giant cells of the giant cell tumor].

OBJECTIVE: To harvest high purified osteoclast-like giant cells from the giant cell tumor by using trypsin and EDTA(ethylenediamineteraacetic acid) digestion. And explore the role and the origin of the multinucleated giant cells of the giant cell tumor. METHODS: Multinucleated giant cells were isolated and cultured from 8 cases of giant cell tumor of the long bone. After 20 hours of culture, 0.5 g.L-1 trypsin/0.2 g.L-1 EDTA was applied to detach the mononuclear stromal cells. The isolated multinucleated giant cells were inoculated on dentine slice to observe bone resorption ability in vitro. Immunohistochemistry study with V-ATPase, CA II (carbonic anhydrate II), cathepsin K, MMP-9 (matrix metalloproteinase-9), CD68 and TRAP(tartrate-resistant acid phosphatase) staining were carried out in the purified multinucleated giant cells. RESULTS: We obtained 85% purified multinucleated giant cells by trypsin/EDTA digestion. Multinucleated giant cells formed resorption lacunae on dentine slice in vitro and positively stained for V-ATPase, CA II, cathepsin K and MMP-9. The TRAP staining was also positive. CONCLUSION: Using 0.5 g.L-1 trypsin/0.2 g.L-1 EDTA digestion can get high purified multinucleated giant cells from the giant cell tumor. The multinucleated giant cells match all the character of the osteoclast and may originate from the fusion of the mononuclear stromal cells of the lesion.

[Genistein inhibits the promotive effect of IL-1beta on osteoclastic bone resorption].

OBJECTIVE: To investigate the effect of genistein, a soybean-derived isoflavone, on the stimulating effect on bone resorption of IL-1beta. METHODS: The osteoclasts (OCs) were isolated with the methods of Yu Shifeng. The rat calvaria were cultured as an organ. The cells in the experiment were grown in four respectively: Control (without genistein or IL-1beta), 10(-6) mol/L genistein,10 microg/L IL-1beta and 10(-6)mol/L genisteine + 10 microg/L IL-1beta. The area of bone resorption, the concentration of Ca(2+) in the supernatant liquid of OCs cultures and mice calvaria were tested. The contents of acid phosphatase(ACP) were also examined by biochemistry method. The index of bone resorption was counted as the ratio of the experiment average and control ones, which indicated the increase in bone resorption when it was above 1.0. RESULTS: The area of bone resorption of 10(-6) mol/L genisteine + 10 microg//L IL-1beta increased compared with that of 10(-6) mol/L genistein, while the concentration of Ca(2+) in the supernatant liquid of OCs cultures decreased significantly. The index of bone resorption of 10(-6) mol/L genisteine + 10 microg//L IL-1beta lied between 10(-6) mol/L genistein and 10 mug/L IL-1beta. In the organ culture, there was no difference in the content of ACP among all the groups. The index of bone resorption of 10(-6) mol/L genisteine + 10 microg//L IL-1beta was below that of 10 mug/L IL-1beta, but both were above 1.0. The index of bone resorption was below 1.0 in the group of 10(-6) mol/L genistein. CONCLUSION: Genistein can suppress obviously the bone resorption simulated by single IL-1beta.

[The nature of calcifying odontogenic cysts of the jaws].

OBJECTIVE: To clarify the clinicopathological and behavioral spectrum of the so-called calcifying odontogenic cysts (COC). METHODS: Retrospective analysis of 21 cases previously diagnosed as COC was undertaken to evaluate their clinical, radiographic, pathological and behavioral features. RESULTS: The lesions of this series were divided into three groups, including simple cysts, benign and malignant tumors. The cyst group was composed of 16 cases (9 men, 7 women). The age of the patients peaked at the second decade, with a predilection for the premolar region of the jaws. The clinicopathological features of this group were consistent with that of developmental odontogenic cysts. Follow-up of the 13 patients treated by enucleation revealed no recurrence. The benign tumor group consisted of 4 cases with variable clinicopathologic features. Two cases were solid tumors containing ameloblastomatous epithelium, ghost cells and calcification foci. The other two cases had lesions that contained typical areas of COC and other types of odontogenic tumors (1 ameloblastoma and 1 odontogenic fibromyxoma). All the 4 cases occurred in the mandible with a relative large size. Two of which had a history of multiple recurrences. Only one case was identified as malignant tumor based on its infiltrative growth pattern and histological features. CONCLUSIONS: The so-called COC, previously recognized as a pathologic entity, can show extreme diversity in its clinical and histopathological features as well as in its biological behavior. Thus, the subgroups as simple cyst, benign and malignant tumors should be clarified and treated accordingly. Their terminology and classification should be reconsidered.