"Dramatic Growth" of Microbial Aerosols for Visualization and Accurate Counting of Bioaerosols.

While the global COVID-19 pandemic has subsided, microbial aerosol detection has become of high concern. Timely, accurate, and highly sensitive monitoring of microbial aerosols in indoor air is the basis for effective prevention and control of infectious diseases. At present, no commercial equipment or reliable technology can simultaneously control the detection time and limit at 6 h and 102 CFU/mL, respectively. Based on the "safety size range" of particulate matter in the air, we propose a new method of microbial dilation detection, which enables the pathogen to grow rapidly and dramatically into a polymeric microsphere, larger in size than the coexisting aerosol particles. "Like a crane standing among chickens", the microorganism can be easily visualized and counted. Different from routine chemical and biological sensing technologies, this method can achieve absolute counting of microbial particles, and the simple principles can be developed into devices for different life scenarios.

Engineering a SERS Sensing Nanoplatform with Self-Sterilization for Undifferentiated and Rapid Detection of Bacteria.

The development of a convenient, sensitive, rapid and self-sterilizing biosensor for microbial detection is important for the prevention and control of foodborne diseases. Herein, we designed a surface-enhanced Raman scattering (SERS) sensing nanoplatform based on a capture-enrichment-enhancement strategy to detect bacteria. The gold-Azo@silver-cetyltrimethylammonium bromide (Au-Azo@Ag-CTAB) SERS nanotags were obtained by optimizing the synthesis process conditions. The results showed that the modification of CTAB enabled the nanotags to bind to different bacteria electrostatically. This SERS sensing nanoplatform was demonstrated to be fast (15 min), accurate and sensitive (limit of detection (LOD): 300 and 400 CFU/mL for E. coli and S. aureus, respectively). Of note, the excellent endogenous antibacterial activity of CTAB allowed the complete inactivation of bacteria after the assay process, thus effectively avoiding secondary contamination.

High-Aperture-Ratio Dual-View Integral Imaging Display.

Low aperture ratio is a problem in the conventional dual-view integral imaging (DVII) display using a point light source array. A high-aperture-ratio DVII display using a gradient width point light source array is reported in this work. The elemental Images 1 and 2, which are alternatively aligned on a liquid crystal panel, are illuminated by the light rays emitted from an assigned point light source. The optical path is optimized by optimizing the widths of the point light sources. The aperture ratio of the proposed DVII display was demonstrated as 1.88 times the conventional DVII display. Experiments showed that the vertical viewing range is related to the vertical width of the first row point light source, whereas the aperture ratio is related to the vertical widths of all point light sources. By optimizing the widths of the point light sources, the aperture ratio is enhanced without loss of viewing range.

Dual-view integral imaging display using a polarizer.

We propose a dual-view integral imaging display using a polarizer. It consists of a display panel, a polarizer, a microlens array, and two pairs of polarizer glasses. The polarizer comprises the left and right subpolarizers whose polarization directions are orthogonal. Two kinds of elemental images are captured from different three-dimensional scenes and located on the left and right half of the display panel. The lights emitting from two kinds of elemental images are polarized by the left and right subpolarizers. The polarization directions of the two pairs of polarizer glasses used in the left and right viewing zones are the same as those of the right and left subpolarizers, respectively. Two different three-dimensional images are simultaneously viewed in the left and right viewing directions by wearing two pairs of polarizer glasses. A prototype of the proposed dual-view integral imaging display is developed, and the experimental results verify the hypothesis.

Graphene oxide-highly anisotropic noble metal hybrid systems for intensified surface enhanced Raman scattering and direct capture and sensitive discrimination in PCBs monitoring.

Graphene oxide (GO)-anisotropic noble metal hybrid systems were developed as highly sensitive and reproducible surface enhanced Raman scattering (SERS) platform, in which ultrathin GO was embedded between two metallic layers of flower-like Ag nanoparticles (AgNFs) and gold nanostars (AuNSts). Due to multi-dimensional plasmonic coupling effect, the well-designed AgNFs-GO-AuNSts sandwich structures possessed ultrahigh sensitivity with the detection limit of R6G as low as 1.0 × 10-13 M and high enhancement factor of 2.59 × 107. Additionally, the GO interlayer could function as protective shell to suppress the oxidation of bottom silver layer and efficiently position the target analytes within hot spots. These features endow the substrate with high stability and excellent reproducibility (Signal variations < 7%). Particularly, the GO sandwiched substrate can be explored for the direct capture and sensitive detection of polychlorinated biphenyls (PCBs) without any organic modifier as molecule harvester. This minimum detected concentration was estimated as low as 3.4 × 10-6 M. The detection method based on GO mediated sandwich substrate avoids complicated surface modification manipulations and improves the substrate cleanness. Moreover, the resultant sandwich substrates can be used to recognize fingerprint peaks of different PCBs in their complex mixture, revealing great potential applications in SERS-based simultaneous detection of multiple pollutants with low affinity.

Dual-view integral imaging three-dimensional display using polarized glasses.

We propose a dual-view integral imaging (DVII) three-dimensional (3D) display using polarized glasses. The DVII 3D display consists of a display panel, a polarized parallax barrier, a microlens array, and two pairs of polarized glasses. Two kinds of elemental images, which are captured from two different 3D scenes, are alternately arranged on the display panel. The polarized parallax barrier is attached to the display panel and composed of two kinds of units that are also alternately arranged. The polarization directions between adjacent units are perpendicular. The polarization directions of the two pairs of polarized glasses are the same as those of the two kinds of units of the polarized parallax barrier, respectively. The lights emitted from the two kinds of elemental images are modulated by the corresponding polarizer units and microlenses, respectively. Two different 3D images are reconstructed in the viewing zone and separated by using two pairs of polarized glasses. A prototype of the DVII 3D display is developed and two 3D images can be presented simultaneously, verifying the hypothesis.

Autostereoscopic 3D display with high brightness and low crosstalk.

An autostereoscopic 3D display with high brightness and low crosstalk is proposed. This display consists of a liquid crystal display (LCD) panel, a reflective light source (RLS), and a parallax barrier or lenticular lens. The RLS behind the LCD panel consists of a light source, a light guide plate, and a reflection cavity. The RLS can make light reflect continuously in the reflection cavity and exit from the slits on the cavity surface. The widths of these slits are narrower than those of the subpixels, so they can provide a low aperture ratio, which is helpful in obtaining low crosstalk. Because of the reflection cavity, the optical efficiency is higher than that using a single barrier. The parallax barrier or lenticular lens can project parallax images on the LCD panel into different directions. Then 3D images are formed. A prototype of the proposed 3D display having high brightness 3D images and low crosstalk is developed. The experimental results agree well with the theory.

Reflected-light-source-based three-dimensional display with high brightness.

A reflected-light-source (RLS)-based 3D display is proposed. This display consists of an RLS and a 2D display panel. The 2D display panel is located in front of the RLS. The RLS consists of a light source, a light guide plate (LGP), and a reflection cavity. The light source and the LGP are located in the reflection cavity. Light from the light source can enter into the LGP and reflect continuously in the reflection cavity. The reflection cavity has a series of slits, and light can exit only from these slits. These slits can work as a postpositional parallax barrier, so when they modulate the parallax images on the 2D display, 3D images are formed. Different from the conventional 3D display based on a parallax barrier, this RLS has less optical loss, so it can provide higher brightness. A prototype of this display is developed. Experimental results show that this RLS-based 3D display can provide higher brightness than the conventional one.