Three bioceramic sealers (EndoSequence BC sealer, EndoSeal MTA, and MTA Fillapex) and three epoxy resin-based sealers (AH-Plus, AD Seal, and Radic-Sealer) were tested to evaluate the physicochemical properties: flow, final setting time, radiopacity, dimensional stability, and pH change. The one-way ANOVA and Tukey's post hoc test were used to analyze the data (P = 0.05). The MTA Fillapex sealer had a highest flow and the BC Sealer presented a flow significantly lower than the others (P < 0.05). The BC Sealer and MTA Fillapex samples were not set in humid incubator condition even after one month. EndoSeal MTA had the longest setting time among the measurable materials and Radic-Sealer and AD Seal showed shorter setting time than the AH-Plus (P < 0.05). AH-Plus and EndoSeal MTA showed statistically higher values and MTA Fillapex showed statistically lower radiopacity (P < 0.05). BC Sealer showed the highest alkaline pH in all evaluation periods. Set samples of 3 epoxy resin-based sealers and EndoSeal MTA presented a significant increase of pH over experimental time for 4 weeks. In conclusion, the bioceramic sealer and epoxy resin-based sealers showed clinical acceptable physicochemical properties, but BC Sealer and MTA Fillapex were not set completely.

The aim of this study was to assess the effect of three calcium silicate-based sealers (EndoSeal MTA, Nano-ceramic Sealer, and Wellroot ST) and two epoxy resin-based sealers (AH-Plus, AD Seal) on various aspects, such as cell viability, inflammatory response, and osteogenic potential, of human periodontal ligament stem cells (hPDLSCs). AH-Plus showed the lowest cell viability on hPDLSCs in all time periods in fresh media. In set media, hPDLSCs showed no significant differences in cell viability among all the tested materials. Wellroot ST showed the highest level of cell adhesion and the morphology of attached cells. AH-plus presented a significantly higher expression of IL-6 and IL-8 than the other sealers. AD Seal and three calcium silicate sealers showed high expression of the mesenchymal stem cell markers. ALP mRNA expression showed a significant increase in time-dependent manner on all of three calcium silicate-based sealers, which do not seem to interfere with the differentiation of hPDLSCs into osteoblasts. Based on the results from this study, calcium silicate-based sealers appear to be more biocompatible and less cytotoxic than epoxy resin-based sealers. Meanwhile, further and long-term clinical follow-up studies are required.

Nanostructured biosensors have pioneered biomedical engineering by providing highly sensitive analyses of biomolecules. The nanowell array (NWA)-based biosensing platform is particularly innovative, where the small size of NWs within the array permits extremely profound sensing of a small quantity of biomolecules. Undoubtedly, the NWA geometry of a gently-sloped vertical wall is critical for selective docking of specific proteins without capillary resistances, and nanoprocessing has contributed to the fabrication of NWA electrodes on gold substrate such as molding process, e-beam lithography, and krypton-fluoride (KrF) stepper semiconductor method. The Lee group at the Mara Nanotech has established this NW-based biosensing technology during the past two decades by engineering highly sensitive electrochemical sensors and providing a broad range of detection methods from large molecules (e.g., cells or proteins) to small molecules (e.g., DNA and RNA). Nanosized gold dots in the NWA enhance the detection of electrochemical biosensing to the range of zeptomoles in precision against the complementary target DNA molecules. In this review, we discuss recent innovations in biomedical nanoengineering with a specific focus on novel NWA-based biosensors. We also describe our continuous efforts in achieving a label-free detection without non-specific binding while maintaining the activity and stability of immobilized biomolecules. This research can lay the foundation of a new platform for biomedical nanoengineering systems.

Miniaturized microfluidic biosensors have recently been advanced for portable point-of-care diagnostics by integrating lab-on-a-chip technology and electrochemical analysis. However, the design of a small, integrated, and reliable biosensor for multiple and simultaneous electrochemical analyses in a single device remains a challenge. Here, we present a simultaneous microfluidic electrochemical biosensing system to detect multiple biomarkers of pulmonary hypertension diseases in a single device. The miniaturized biosensor, which is composed of five chambers, is precisely and individually controlled using in-house-built pneumatic microvalves to manipulate the flow pathway. Each chamber is connected to an electrochemical sensor designed to detect four different biomarkers plus a reference control. Our design allows for loading of multiple reagents for simultaneous analyses. On the basis of the developed microfluidic electrochemical sensor system, we successfully detected four well-defined pulmonary hypertension-associated biomarkers, namely, fibrinogen, adiponectin, low-density lipoprotein, and 8-isoprostane. This novel approach offers a new platform for a rapid, miniaturized, and sensitive diagnostic sensor in a single device for various human diseases.

FFPE biopsy tissues are an adequate source for FGFR2 evaluation in gastric carcinomas, and a qPCR-based copy number assay can be used for screening. IHC is also a valid and practical method for evaluating FGFR2, considering frequent heterogeneity.

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We demonstrate a simple and efficient one-step procedure for synthesizing a solid state polypyrrole (PPy) thin film for supercapacitor applications using alternating current impedance spectroscopy. By controlling the frequency and amplitude we were able to create unique PPy nano/microstructures with a particular morphology of the loop. Our PPy micro/nanosphere shows extremely high capacitance of 568 F/g, which is close to the theoretical value of 620 F/g and 20-100% higher than that of other reported PPy electrodes. Most of all, this material presents high capacitance and significantly improved electrochemical stability without pulverization of its structure, demonstrating 77% retention of the capacitance value even after 10 000 charge/discharge cycles. These results are a consequence of the larger surface area and adequate porosity generated due to the balance between the nano/micro PPy loops. This created porous structure also allows the favored penetration of electrolyte and high ion mobility within the polymer and prevents the mechanical failure of the physical structure during volume variation associated with the insertion/deinsertion of ions upon cycling.

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