Parallel Light Engine Performance monitoring Using the Onboard Control GUI
AURA, CELESTA, RETRA, SPECTRA, and ZIVA Light Engines incorporate a control GUI accessed through a web browser via anethernet connection.Image acquisition applications used to control the light engine though connection of either the USB or RS232 serial ports can be run in parallel with ethernet-connected control GUI to aid in trouble-shooting.As shown in Figure 1, this allows the light engine to be controlled by the image acquisition software, while the GUI serves as a passive monitor of the light engine status.
Figure 1. Screenshots of parallel operation of image acquisition software (NIS Elements, left) and CELESTA Light Engine Control GUI (right). A. NIS Elements command to turn on red light output at 21.7% is inoperative. Examination of the GUI display reveals that this is due to an open interlock condition (e.g. no optical fiber connected to the light engine output port). B. After closing the interlock, the same NIS Elements command results in light output, indicated by the filled red channel radio button and non-zero output power reading in the GUI.
The control GUI displays many types of information pertinent to the performance of the light engine that are not accessible in current releases of most image acquisition software packages. These include:
Real-time light output power readouts
Standby mode status
Light engine operating software error messages
Humidity/dew point data
Serial port configuration
TTL port configuration
Cumulative run time data
In cases where the PC being used for image acquisition control has a single ethernet port that is dedicated to internet access, a USB-to-ethernet adapter (Figure 2) can be used for connection to the light engine control GUI.USB-to-ethernet adapters are readily available from online vendors for less than $20.
Single-cell Characterization of Immunization Responses
The current Covid-19 pandemic has sparked an urgent need for improvements in the characterization of the immune response to vaccinations. Although simple and robust, conventional antibody titer measurements provide little information on the phenotypic diversity of IgG-secreting cells (IgG-SCs), the functional properties of the antibodies they produce or the temporal profile of the immune reaction in response to an antigenic challenge. In a recent paper published in the Journal of Immunology  and other recent publications [2,3], a team of researchers based in Paris and Zurich describe the application of a single-cell analysis technique known as DropMap to provide quantitative analysis of the distribution of antibody secretion rates and affinities over the course of an immune response. The DropMap protocol begins with microfluidically controlled compartmentalization of single splenocytes, extracted from mice at time points up to 8 weeks after immunization, in individual 50-picoliter droplets together with immunomagnetic beads and fluorescently-labeled antigens and anti-IgG antibodies. The beads are magnetically aligned to form micrometer-sized structures that can be visualized by fluorescence microscopy using a SOLA light engine.Bead capture of red-fluorescent anti-IgG (Fc) identifies IgG-SCs, allowing determination of their frequency.Capture of green-fluorescent antigen provides information on antigen binding affinity. To accumulate population statistics, two-dimensional arrays containing >10,000 cell-containing droplets are imaged every 7.5 minutes over 37.5 minutes. The SOLA light engine provides the exceptional light output stability required to extract reliable quantitative information across thousands of droplets and multiple time points.