Direct detection of virus-like particles using color images of plasmonic nanostructures.

We propose a measurement method for sensitive and label-free detections of virus-like particles (VLPs) using color images of nanoplasmonic sensing chips. The nanoplasmonic chip consists of 5×5 gold nanoslit arrays and the gold surface is modified with specific antibodies for spike protein. The resonant wavelength of the 430-nm-period gold nanoslit arrays underwater environment is about 570 nm which falls between the green and red bands of the color CCD. The captured VLPs by the specific antibodies shift the plasmonic resonance of the gold nanoslits. It results in an increased brightness of green pixels and decreased brightness of red pixels. The image contrast signals of (green - red) / (red + green) show good linearity with the surface particle density. The experimental tests show the image contrast method can detect 100-nm polystyrene particles with a surface density smaller than 2 particles/µm2. We demonstrate the application for direct detection of SARS-CoV-2 VLPs using a simple scanner platform. A detection limit smaller than 1 pg/mL with a detection time less than 30 minutes can be achieved.

Examining patient flow in a tertiary hospital's emergency department at a low coronavirus prevalence region.

BACKGROUND: Taiwan's successful containment of the COVID-19 outbreak prior to 2021 provided a unique environment for the surveillance of unnecessary emergency medical use. The aim of the study is to examine the impact of the coronavirus disease (COVID-19) pandemic on the patient flow in the emergency department (ED) of a tertiary hospital over 1 year in southern Taiwan, a region with low COVID-19 prevalence. METHODS: Cross-sectional observational study was conducted from January to December 2020. Essential parameters of patient flow in the ED between January and February 2020 and the subsequent 11-month period were compared to data from 2019. Data were analyzed with descriptive statistics, using an independent sample t-test or Mann-Whitney U test, as applicable. RESULTS: The ED census showed an acute decline (- 30.8%) from January to February 2020, reaching its nadir (- 40.5%) in April 2020. From February to December 2020, there was an average decrease of 20.3% in ED attendance (p < 0.001). The impact was most significant in ambulatory visits, lower-urgency acuity (level III) visits, and pediatric visits, without change in the acuity proportion. The length of stay shortened mainly in the adult division, which typically had an overcrowding problem (median, 5.7-4.4 hours in discharge; 24.8-16.9 hours in hospitalization; p < 0.001). The incidence of 72-hour unscheduled return visits was also reduced (4.1-3.5%, p = 0.002). CONCLUSIONS: In contrast to devastated regions, the impact on the ED patient flow in regions having low COVID-19 prevalence highlights a remodeling process of emergency medical care that would improve overcrowding.