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ASSAY OVERVIEW

Nirmidas Biotech Inc. announces the availability of pGOLD™ COVID-19 IgG/IgM or IgG/IgM/IgA Assay kits for simultaneous, multiplexed detection of IgG, IgM and IgA antibodies against COVID-19, each assay requiring only 1 micro-liter of patient sera, plasma or whole blood (fresh or from dried spots on blood cards). This assay is initially for research use only. It will be eligible for LDT tests in clinical labs upon implementations. 

The pGOLD™ COVID-19 IgG/IgM Assay is in an ELISA type of format. Each pGOLD™ biochip can run 48 samples with controls in each run that takes about 2 hours to complete. The current version of pGOLD™ assay simultaneously detects in a sample IgG and IgM against three SARS-CoV-2 specific antigens, and can be easily extend to more antigens (customizable) and can also include IgA test. In each assay run, one obtains the IgG and IgM status against multiple coronavirus antigens (including various common coronaviruses) for each of the 48 samples. 

Nirmidas can provide pGOLD™ biochip with printed antigen arrays for ELISA type of use. The biochip can be ready by existing western blot reader or by Nirmidas’ MidaScan™ dual channel instrument. Nirmidas also offers assay service testing samples provided by customers and reporting results. 

SUPERIOR PRECISION AND SENSITIVITY

pGOLDTM COVID-19 IgG/IgM Assay is superior in sensitivity and accuracy. It detects ~ 5 logs of antibody concentrations with ~ 4-5 logs of signal dynamic range (see Figure 1 & 2 below), owing to nano-plasmonic enhanced NIR fluorescence detection (see Nature Medicine, DOI: 10.1038/nm.4302). 

In terms of assay sensitivity, pGOLD™ assay detects purified SARS-CoV-2 IgG with a limit of detection LOD ~ 1.6 ng/mL (~ 11 pM). For an COVID-19 infected patient, pGOLD™ can detect IgG and IgM after diluting the serum significantly by ~ 100,000-500,000 times (Figure 1 & 2).

Figure 1.

Left Picture: pGOLD™ NIR fluorescence image of SARS-CoV-2 IgG signals of purified IgG antibody (left column) under a series of dilutions together with a 200X diluted serum of a healthy control (HC). Each dilution was assayed in a square well in which different SARS-CoV-2 antigens were printed in different horizontal rows. Right column is SARS-CoV-2 IgG signals of a PCR confirmed COVID-19 patient serum under the same series of dilutions. In comparison to a rapid antibody tests, the LoD based on pGOLD™ assays is ~ 100 times higher.

Right Picture: IgM result similar to the left. No signal on the left column of the slide since the purified anti SARS-CoV-2 IgG is specific to IgG and free of any IgM.

Figure 2.

Top Graph : Log10 of SARS-CoV-2 IgG signals against two SARS-CoV-2 antigens vs. dilution factor for the serum of a PCR confirmed COVID-19 patient. Clear IgG signal is seen for 204.8K dilution (P-204.8K means patient serum diluted by 204,800 times. HC-200K means healthy control serum diluted by 200 times). Signal was saturated for 200X and 800X dilution.

Bottom Graph: The same results for IgM.

OTHER FEATURES OF THE ASSAY KIT

• Simultaneous SARS-CoV-2 IgG/IgM assay for multiple COVID-19 antigens.

• ELISA-like pGOLD™ biochip with printed antigen arrays. The biochip can be read by existing western blot reader or by Nirmidas’ MidaScan™ dual channel instrument.

• Cross-reactivity testing with other coronaviruses infections.   

MULTIPLEXED PGOLD™ ASSAY WITH CUSTOMIZED CORONAVIRUS ANTIGENS

Nirmidas is open to provide service on customized assays on the pGOLD™ platform, with any coronavirus related antigens provided by Nirmidas or customers in single-plex or multiplexed formats.  

TESTING SERVICE 

Nirmidas provides testing service for samples provided by customers, and can report IgG, IgM and IgA status against multiple coronavirus antigens for each sample. Please inquire at info@nirmidas.com

 Learn More About pGOLD™ COVID-19 IgG/IgM Assay