Analysis of Nitrogen Dioxide in Environment

As a severe environmental pollutant, detection and quantitation of nitrogen dioxide (NO2) have been studied for centuries. In this review, recent progress of NO2 analysis in the atmosphere will be summarized. Four major types of detection technologies, including traditional chemical detection, optical detection, solid-state field effect transistor detection, and other detection technology are covered. The standard method employed by the US EPA, which is based on luminol, is the most reliable and robust method that is used for fully validated monitoring. In the past two decades, accompanying the fast development of electrical engineering and integrated circuit, micro to nanoscale gas sensors have been gaining more and more attention. Application of novel materials including nano wires and graphene also leads to a new era of research and development of sensors.

Preparation of Functional Magnetic Nanoparticles and its Application in Diagnostic Analysis

The magnetic nanoparticles modified with carboxyl functional group were synthesized and characterized. These nanoparticles covalently bound with hepatitis B surface antibody（HBsAb）, were used to detect hepatitis B surface antigen （HBsAg） in immunovoltammetry. The detection limit was found to be 0.06 ng/mL, which is much higher than that of enzyme-linked immunosorbent assay （ELISA） used in clinical analysis.

Detection of chemicals in water using a three-dimensional graphene porous structure as liquid-vapor separation filter

In this study, we report the utilization of a three-dimensional （3D） porous graphene structure as liquid-vapor separation filter, which allows the passage of chemical vapors while blocking liquid chemicals and water. The blockage of liquid chemicals and water from semiconducting sensing regions is required to avoid abnormal transistor characteristics. In order to impart omniphobic characteristics, a （heptadecafluoro-1,1,2,2-tetrahydrodecyl）trichlorosilane （HDF-S） self-assembled monolayer was coated on the surface of the 3D porous graphene structure. The concentration of chemical agents in water could be consistently detected by observing the shift in the threshold voltage in the oxide nanowire transistor covered by the HDF-S self-assembled 3D graphene structure. The proposed monitoring method is expected to offer means for application in different environments by providing a stable sensing performance.

Tagged molecule induced nanoparticle aggregation:Raman reporter-labeled immuno-Au aggregate as immuno-sensor

A novel structure with high surface enhanced Raman scattering （SERS） activity and bio-specificity as a SERS-based immuno-sensor （named as Raman reporter-labeled immuno-Au aggregate） is demonstrated and employed for protein detection. In each fabrication process, the features of those aggregates are obtained and characterized by ultraviolet-visible （UV-Vis） extinction spectra, transmission electron microscopy （TEM） images, scanning electron microscopy （SEM） pictures, and SERS spectra. Experimental results indicate that proper amounts of the reporter molecules can result in the moderate aggregation morphologies of gold nanoparticles. Compared with the previously reported method using Raman reporterlabeled immuno-Au nanoparticles, more sensitive SERS-based protein detection is realized with this novel immuno-sensor.

Translation of the long-term fundamental studies on viral DNA packaging motors into nanotechnology and nanomedicine

Many years of fundamental studies on viral genome packaging motors have led to fruitful applications.The double-stranded DNA(dsDNA)viruses package their genomes into preformed protein shells via nanomotors including several elegant and meticulous coaxial modules.The motor is geared by the hexameric RNA ring.An open washer displayed as hexametric string of phi29 motor ATPase has been reported.The open washer linked into a filament as a queue with left-handed chirality along the dsDNA chain.It was found that a free 5′-and 3′-dsDNA end is not required for one gp16 dimer and four monomers to assemble into the hexametric washer on dsDNA.The above studies have inspired several applications in nanotechnology and nanomedicine.These applications include:(i)studies on the precision motor channels have led to their application in the single pore sensing;(ii)investigations into the hand-in-hand integration of the hexametric pRNA ring have resulted in the emergence of the new field of RNA nanotechnology;and(iii)the studies on the motor stoichiometry of homologous multi-subunits that subsequently have inspired the discovery of new methods in highly potent drug development.This review focuses on the structure and function of the viral DNA packaging motors and describes how fundamental studies inspired various applications.Given these advantages,more nanotechnological and biomedical applications using bacteriophage motor components are expected.

Fiber-optic surface plasmon resonance-based sensor with AZO/Au bilayered sensing layer

We describe a surface plasmon resonance-based fiber sensor based on a side-polished graded-index mul- timode fiber, in which an Al-doped zinc oxide/gold （AZO/Au） bilayer is deposited on the side-polished surface of the fiber core to improve the detection sensitivity of the device. The AZO/Au layer is used as the active sensing member of the device with a combination of a 75-nm-thick AZO layer and a 40-nm-thick Au layer. Such a device is then applied to the concentration measurement of CHaCOONa solutions, as an example showing a good response to concentration variation. The results indicate that the additional AZO layer in the active sensing member may lead to higher detection sensitivity and greater measurement stability in the measurements of solution concentration.