Nirmidas lays groundwork for In-vitro Diagnostic products with pGOLD™ slides registered under CE Mark

ce mark box.jpg

“This is only the beginning of building our portfolios for CE-marked IVD products“ says CEO Meijie Tang. “pGOLD™ slides are the foundation for Nirmidas Multiplexed Assay Kits, like the Zika/Dengue and IgG Avidity Assay. They’re used in our 5-year supply and service agreement with a CLIA lab for the development of clinical testing.”

pGOLD™ slides are produced in a manufacturing lab in compliance with ISO13485 regulations.  The production follows rigorous work instructions and quality control procedures. They ensure consistent performance and stability for use in research and development, and clinical tests in the near future.

Nirmidas has brought plasmonic gold technology (pGOLD™), an innovative signal amplifying platform, from scientific research to use in diagnostic assays (Research Use Only). pGOLD™ slides are a critical component in highly sensitive fluorescence enhanced multiplex assays.

Looking forward, Nirmidas is “working on building partnerships in the European Market and beyond. We see great potential for growth in diagnostic product development”. In addition, Nirmidas is seeking FDA clearance for its assay kits using the pGOLD™ slides.

Nirmidas reaches a five-year product and service agreement with a CLIA lab to provide plasmonic pGOLD™ based diagnostic tests

Nirmidas reaches a five-year product and service agreement with a CLIA lab to provide plasmonic pGOLD™ based diagnostic tests

On October 24th, 2018 Nirmidas reached a 5-year Product and Service Agreement with a LDT lab of a major healthcare provider in California, establishing partnership and collaboration with a highly reputable diagnostic lab with CLIA certificates to develop novel assays for clinical testing nationwide

Nirmidas Launches New NIR-I-II-azide Dye

Nirmidas is pleased to announce our new, NIR-I-II (IR-12N3) Dye:

  • For both NIR-I and NIR-II fluorescence imagining in 800-1400 nm range
  • Low Cost, High Brightness (high molar extinction coefficient and quantum yield in serum/blood)
  • N3 azide functionalization for highly efficient conjugation
  • Price: $200/mg. Minimum order: 5 mg

Nirmidas continues to offer the existing NIR-II dye products:

  • IR-E1050
  • IR-E1050-COOH
  • IR-T1050
  • IR-m1050
  • IR-NP

Contact us to learn more at

Nirmidas Multiplexed IgG/IgM test on pGOLD platform in Diagnostic Microbiology & Infectious Disease Journal

Validation of IgG, IgM multiplex plasmonic gold platform in French clinical cohorts for the serodiagnosis and follow-up of Toxoplasma gondii infection

Diagnostic Microbiology & Infectious Disease, March 2017 Volume 87, Issue 3, Pages 213–218

Christelle Pomares, Bo Zhang, Shylaja Arulkumar, Geraldine Gonfrier, Pierre Marty, Su Zhao, Steven Cheng, Meijie Tang, Hongjie Dai, Jose G. Montoya


We report the use of the multiplexed T. gondii IgG, IgM test on plasmonic gold (pGOLD) platform in the setting of T. gondii infection by analyzing 244 sera from Nice, France (seroconversion, chronically infected, non-infected and newborns serum samples). Results were compared with commercial tests for the detection of IgG and IgM and their overall clinical final interpretation of a complete serological profile. The IgG and IgM test results on the platform were in agreement in, respectively, 95% and 93% with the commercial kits. When comparing with the overall clinical interpretation of the serological profile, the agreement reached 99.5% and 97.7% for IgG and IgM, respectively. This innovative pGOLD platform allows detection of both IgG and IgM simultaneously with only ~1 microliter of serum. The multiplexed IgG/IgM test on pGOLD platform is a strong candidate for its use in the massive screening programs for toxoplasmosis during pregnancy.

Read more at Diagnostic Microbiology & Infectious Disease

Nirmidas Biotech Awarded Grant by National Institute of Health

Nirmidas Biotech, Inc, in collaboration with Stanford’s Departments of Pathology and Medicine, received an award from the National Institute of Health on March 24, 2017.

Nanoscale plasmonic-gold platform assay module

Nanoscale plasmonic-gold platform assay module

The grant is for a nanoscale plasmonic-gold platform for specific diagnosis of Zika and differentiation from other flavivirus infections. The underlying technology for this grant was recently published in Nature Medicine.

Read more about our Zika Dengue IgG/IgA and IgG Avididty assay kits which are available now.

Nirmidas Diagnostic Assays in BioCentury Innovations

ASSAYS AND SCREENS By Hongjiang Li appeared in BioCentury Innovations

TECHNOLOGY: Diagnostic assays

A plasmonic chip-based microarray could help aid the differential diagnosis of Zika and dengue infections. The assay utilized a gold plasmonic chip-based microarray printed with Zika virus genome polyprotein (GP1) and dengue viral particles for capture of virus-reactive antibodies from human... Read more at BIOCENTURY



Nirmidas pGOLD (plasmonic gold) Serology Assays for the Diagnosis of Zika and Dengue

For research use only

Zika/Dengue Assay Kit Example

Zika/Dengue Assay Kit Example

Nirmidas Biotech Inc. announces the availability of three pGOLD-Zika/Dengue IgG/IgM/IgA Assay kits for rapid, simultaneous, multiplexed detection of IgG, IgM and IgA antibodies against Zika virus (ZIKV) and Dengue virus (DENV), each requiring only 1 micro-liter of patient sera. A unique IgG avidity test against both ZIKV and DENV is also developed. These assays, published in the March 6 issue of Nature Medicine can facilitate differentiating ZIKV from DENV infection, and revealing whether the infection occurred recently (low avidity) or in the past (high avidity) for both Zika and Dengue infections.

The current Zika diagnostic tests are non-ideal due to narrow diagnostic window (RNA detection by PCR), cross reactivity (Zika IgM test) or time-consuming and laborious procedures (plaque reduction neutralization testing, PRNT). The simultaneous ZIKV and DENV IgG/IgA testing, enabled by the pGOLD assay, is novel with an important finding that the cross-reactivity problem between ZIKV and DENV IgG and IgA antibodies occurs at a much lower degree than IgM antibodies, thus allowing highly specific diagnosis of ZIKV infection and differentiation from Dengue infection. ZIKV IgA positivity is found to be highly specific to early stage ZIKV infection. For a ZIKV infected cohort with symptom onset to sample collection time of 2-90 days in the acute-convalescent phase, the pGOLD IgG/IgA test can diagnose ZIKV infection with > 90% sensitivity and ~ 98% specificity, with little cross-reactivity problem due to chronic or on-going DENV infection. For an acute-phase ZIKV infected (< 6 days after symptom onset, positive by PCR test) cohort from the Dominican Republic, the pGOLD IgG/IgA assay can still detect ~ 47% of the ZIKV infection.

Assay Kits Available:

1. Simultaneous Zika/Dengue IgG IgA test against ZIKV NS1 and DENV viral antigens

  • Uses low sample volume of ~ 1 µl

  • ~ 2-hour processing time for results

  • IgG and IgA are reported by two different colors of fluorescence.

2. Simultaneous Zika/Dengue IgG IgM test against ZIKV NS1 and DENV viral antigens

  • Uses low sample volume of ~ 1 µl

  • ~ 2-hour processing time for results

  • IgG and IgM are reported by two different colors of fluorescence.

3. Zika/Dengue IgG avidity

  • Uses low sample volume of ~ 1 µl

  • ~ 2-hour processing time for results

  • IgG is reported by 800 nm NIR fluorescence. Each sample will be tested with and without urea treatment.

Format of assays:

ELISA-like assay plate consisting of 4 pGOLD slides

ELISA-like assay plate consisting of 4 pGOLD slides

pGOLD assay is in a format similar to multi-well microplates widely used in ELISA and can be considered as multiplexed ELISA with very similar assay procedures. Automated washers are readily available and can also be processed manually. Plate reading can be done by MidaScan reader offered by Nirmidas for best results or use existing fluorescence readers.

How the tests can be used:

  • Perform ZIKV/DENV IgG and IgM antibody test; and ZIKV and DENV IgG avidity test.

    • Avidity test can identify if the patient had prior ZIKV or DENV infection.

    • For primary infection without prior flaviviral infection, ZIKV IgG/IgM test can detect ZIKV infection in acute, convalescent and chronic phases.

  • Perform ZIKV/DENV IgG and IgA antibody test; and ZIKV and DENV IgG avidity test.

    • Avidity test can identify if the patient had prior ZIKV or DENV infection.

    • For patients with prior DENV infection as is the case for adults in dengue endemic regions, ZIKV infection would be considered as secondary infection. ZIKV IgG/IgA test can detect ZIKV infection in acute, convalescent and chronic phase. Secondary DENV infection can also be detected by pGOLD IgG/IgM and avidity test.

Multiplexed assay kit for a panel of flaviviral and alphaviral infections:

Nirmidas is developing a multiplexed IgG/IgM and IgG/IgA as well as IgG avidity test for ZIKV, DENV, JEV, YFV, WNV, CHIV, BEV and USUTU. The assay will require only 1 micro-liter of serum or whole blood for simultaneous detection of all major flaviviral and alphaviral infections.

Customized assay:

Nirmidas is open to collaborations on customized assays on the pGOLD platform, with any antigens provided by the customers in single-plex or multiplexed formats for diagnosis of infectious and other diseases.

Testing service:

Nirmidas provides testing service for flaviviral infections at a highly affordable price. 


For purchase of kits, customized assay and assay service, email us at

Research Use Only

We will contact you if you inquire here to learn more about pGOLD-Zika/Dengue IgG/IgM/IgA and IgG Avidity Assay Kits:

Name *

Nirmidas Biotech developed a multiplexed serological test for the diagnosis of Zika and Dengue

Press Release - Palo Alto

Nirmidas Biotech and Hongjie Dai, PhD, in the Department of Chemistry and Benjamin Pinsky, MD, PhD, in the Departments of Pathology and Medicine at Stanford University have developed a multiplexed serological test for rapidly distinguishing Zika virus (ZIKV) infection from dengue virus (DENV) infection, in both acute and convalescent patients.

This breakthrough was published in Nature Medicine on March 6, 2017, titled “Diagnosis of Zika virus infection on a nanotechnology platform.”

ZIKV and DENV are mosquito-borne flaviviruses that now co-circulate throughout much of the tropical and subtropical world. The clinical presentation of patients with acute ZIKV infection typically includes a combination of fever, headache, retro-orbital pain, conjunctivitis, a maculopapular rash, myalgias, and arthralgias. However, patients with Zika fever are often suspected of having dengue. This considerable overlap in clinical presentations coupled with the potential of ZIKV to cause severe fetal and non-fetal manifestations, including congenital neurologic malformations and fetal demise, as well as Guillain-Barré syndrome, underscores the critical importance of accurate ZIKV diagnostics, and the requirement that tests distinguish ZIKV from DENV infection.

The Centers for Disease Control and Prevention (CDC) has issued testing algorithms for the diagnosis of infection in patients with suspected Zika fever that rely heavily on serological testing, particularly for pregnant women.  Major challenges for ZIKV serological testing include the cross-reactivity between anti-ZIKV IgM antibodies and DENV antigens, as well as the cross-reactivity between anti-DENV IgM antibodies and ZIKV antigens. As such, virus-specific IgM detection, a critical component of the diagnostic arsenal for acute infection with mosquito-borne flaviviruses has been of limited utility during the current outbreak in the Americas, requiring time consuming and laborious plaque reduction neutralization testing (PRNT) for confirmation of the identity of the infecting virus.

To address these issues regarding current serological tests, the Nirmidas-Stanford collaboration developed a multiplexed assay on a nanotechnology based plasmonic gold (pGOLD) platform, that is capable of simultaneously detecting IgG, IgM, and IgA antibodies and IgG avidity against both Zika virus and Dengue virus antigens. Importantly, unlike the substantial cross-reactivity observed for IgM antibodies, both ZIKV IgG and IgA antibodies were specific and showed limited cross-reactivity with DENV antigens, allowing clear differentiation of these two infections. Further, ZIKV IgG avidity, a measure of how strongly antibodies bind to the viral antigen, reveals whether the infection occurred recently (low avidity) or in the past (high avidity). 

In addition to these critical multiplexing capabilities, the tremendous fluorescence signal amplification of the pGOLD nanotechnology platform allows all of these tests to be performed with just 1 microliter of serum and results can be obtained within 2 hours.

“This study demonstrates that the combination of IgG and IgG Avidity testing can facilitate distinguishing Zika virus infection from dengue virus infection in dengue experienced patients”, says Dr. Pinsky. “Importantly, these findings suggest that this test may provide a significant advance in the diagnosis of Zika in pregnancy, as it has the potential to both diagnose and determine the timing of infection, analogous to routine use of IgG and IgG Avidity testing during the work-up of other potentially devastating congenital infections, Cytomegalovirus (CMV) and Toxoplasma gondii.”

Nirmidas is making the pGOLD Zika/Dengue IgG/IgA, IgG/IgM and IgG avidity test available for research use immediately, to facilitate both basic and translational studies to better understand Zika virus infection. Further, “We are currently seeking FDA’s Emergency Use Approval (EUA) in order to move our test into the clinic”, says Dr. Meijie Tang, CEO of Nirmidas Biotech Inc. “It is also important to note that our test is highly affordable, and the cost per antibody per sample is just several dollars”.

Nirmidas Biotech Inc. is a Palo Alto based startup company and a graduate of the Stanford StartX accelerator. Nirmidas’s nanoscale pGOLD platform was developed by Professor Hongjie Dai’s laboratory and licensed from Stanford. ‘I am extremely pleased that basic nanoscience research from the lab has the potential of helping solving real-world problems, an urgent problem in the Zika infection case’, says Dr. Dai.


Nirmidas Biotech, Inc.

2458 Embarcadero Way

Palo Alto, CA 94303


About Nirmidas Biotech, Inc.

Nirmidas Biotech, Inc., provides solutions for bio-analytical and diagnostic researchers using plasmonic gold (pGOLD) technology that vastly enhances near-infrared fluorescence signal, optimized over nearly a decade of research. Nirmidas’ pGOLD products include plasmonic gold slides for fluorescence enhanced biological imaging and assays, and multiplexed ELISA like assays for detecting a panel of prenatal infectious diseases, type 1 diabetes and Zika/Dengue infections. Nirmidas Biotech has also pioneered commercial fluorescent agents emitting in the NIR-II 1000-1700 nm range, for deep tissue biological imaging in vivo and with tissues. For more information, please visit:


About StartX

StartX is a 501(c)(3) Stanford-affiliated nonprofit in Silicon Valley that runs one of the world’s top startup accelerator programs. Our mission is to advance the development of the best entrepreneurs through experiential education and collective intelligence. Since launching in 2010, we have supported more than 160 companies and 370 entrepreneurs across a wide spectrum of industries. StartX and StartX Med, dedicated to medical and biotechnology, provides founders with access to a powerful network of entrepreneurs, investors, mentors, and industry partners, along with office space and a variety of other resources. We are supported by Stanford University, Stanford Hospital & Clinics, Kauffman Foundation, Microsoft, Steelcase, Intuit, Blackstone Charitable Foundation, Greylock Partners, Draper Fisher Jurvetson, Sequoia Capital, Merck, Genentech, Johnson & Johnson and many others. For more information, visit

Stanford scientists look deeper into the body with new fluorescent dye

Stanford News

Nirmidas Biotech Inc. has licensed a patent from Stanford University on biocompatible NIR-II dye that can be excited in the 600-900 nm range and fluoresces in the 900-1300 nm range. 

This NIR-II dye product (IR-E1100) has high quantum yield (~ 4 times higher than the Stanford dye and carbon nanotube based dyes), high biocompatibility, and can be renal excreted. This dye can be used for fluorescence imaging with low autofluorescence/low background ex vivo with cells and tissues. 

It is the first commercial NIR-II dye for deep-tissue in vivo fluorescence imaging with various animal models related to cancer, brain, and cardiovascular diseases and vascular imaging in general.  In vivo NIR-II fluorescence imaging can reach millimeters to centimeters tissue depth with spatial resolution in the sub-5 micron to sub-100 micron range. High temporal resolution can also be achieved to produce real-time imaging videos with imaging rate more than 30 frames per second. 

This dye holds a high potential for clinical translation for human use due to its large Stokes' shift (excitation 785nm or 808nm, emission 900nm-1300nm), high quantum yield, low toxicity and rapid elimination from body.

Nirmidas Biotech Raises $2M For Gold Nanomaterial Developed at Stanford

Wall Street Journal

"Nirmidas Biotech Inc., a spin-out from Stanford University with technology that amplifies fluorescence in laboratory samples in a bid to better identify disease, has raised $2 million in seed funding to begin commercialization, the company said. The funding was led by an undisclosed Washington-based firm, joined by an undisclosed angel investor and the Stanford-StartX Fund, the company said." Nirmidas Biotech Raises $2M For Gold Nanomaterial Developed at Stanford

Nirmidas Biotech Raises $2M in seed round for fluorescent dye meant for diagnostics


Stanford University spinout Nirmidas Biotech has raised $2 million in seed funding to commercialize its fluorescence technology that enhances 100-fold a researcher’s ability to detect disease biomarkers, said the company’s R&D director Joshua Robinson. It’s meant to pick up the subtle traces found in blood from early-stage cancer or hard-to-read autoimmune disorders – conditions that typically use fluorescent dye tests."