PharmaSeq

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Proteomics and Immunoassay

Overview

DESIGN OF IMMUNOASSAY ON p-CHIPSDESIGN OF IMMUNOASSAY ON p-CHIPSPharmaSeq’s electronic radio frequency (RF) microchip, or p-Chip, has been developed into an assay platform for use in the fields of genomics and proteomics. Each p-Chip carries biological material (e.g., oligonucleotides, antibodies, antigens) that is linked to it via the chip’s unique RF identification (ID) number. The p-Chip’s ID signal is transmitted when the chip is activated by laser light.

The p-Chip system is proven effective in high-throughput multiplex cell assays. p-Chips can be used as a platform for cell growth and subsequent cell viability screening for cytotoxicity assays. In a single vessel, multiple different cell lines can be screened for their growth rate or sensitivity while being exposed to various agents. 

This technology has seen success in the fields of genomics and proteomics. For example, PharmaSeq and collaborators at The Johns Hopkins University School of Medicine have developed a p-Chip-based immunoassay that significantly improves the specificity of prostate cancer diagnosis. The researchers reported their work in the journal PLOS ONE (2015). An ongoing collaboration with researchers the University of North Texas Health Science Center in Fort Worth, TX, is focused on developing a p-Chip-based assay for detecting and monitoring bladder cancer using urine samples. 

For more information or a quote, contact us at info@pharmaseq.com or (732) 355-0100. We will be happy to discuss your specific needs and provide an estimate. 

The p-Chip System for High-Throughput Multiplex Assays

PharmaSeq’s system for performing multiplex assays consists of a quantity of p-Chips, the Simuplex flow reader, the spin reader for reading p-Chip IDs and software. Each p-Chip is a very small, unitary integrated circuit that can transmit its ID via radio frequency when stimulated by a pulsed laser light. A p-Chip is composed of photocells, a complete electronic circuit, an antenna and a 30-bit memory, allowing for over 1.1 billion unique ID codes. The p-Chip’s surface is made of silicon dioxide, and methods to stably coat the p-Chip with aminosilane compounds are well-established. p-Chips are highly stable in most aqueous solutions and organic solvents tested and have excellent temperature stability. 

After biological material is conjugated to p-Chips, the chips are exposed to the sample and fluorescently stained. The fluorescence of the chips is then quantified in a flow-based custom analyzer (Simuplex) to reveal concentrations of analytes in the sample. The silver island film p-Chip-based platform is a highly sensitive method for quantifying low-abundance biomolecules in nucleic-acid-based assays and immunoassays.

The technology offers the capability of rapidly screening hundreds, or even thousands, of cell lines or cell types that can be concurrently exposed to agents under the same growth and drug exposure conditions. This type of assay provides a method to measure the differences between the cell lines in cell sensitivity to a particular drug. The platform also enables multiparametric (multivariate) analysis. Different constituents of the cell can be stained with dyes emitting fluorescence at different wavelengths. 

Key Points

PharmaSeq’s p-Chip system provides an electronically-encoded approach to performing multiplex assays. The major advantage of the p-Chip system is that biological material is linked to the ID of the p-Chip to which it is attached. The unique ID of each p-Chip precludes the possibility of an identification error. p-Chips are highly stable in most aqueous solutions and organic solvents tested and have excellent temperature stability.

Screening in a fluidic environment is rapid, the number of ID codes is nearly infinite, and costs of tissue culture reagents are low because many cell lines can be assayed in a single dish.

Publications

  1. Li J, Veltri RW, Yuan Z, Christudass CS, Mandecki W (2015) Macrophage inhibitory cytokine 1 biomarker serum immunoassay in combination with PSA is a more specific diagnostic tool for detection of prostate cancer. PLOS One, 10(4), e0122249. http://www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0122249&representation=PDF (free) 

  2. Rich R, Li J, Fudala R, Gryczynski Z, Gryczynski I, Mandecki W (2012) Properties of coatings on RFID p-Chips that support plasmonic fluorescence enhancement in bioassays. Anal Bioanal Chem, 404(8), 2223-2231. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3477286/pdf/nihms406241.pdf http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3477286/pdf/nihms406241.pdf (free)

  3. Li J, Wang Z, Gryczynski I, Mandecki W (2010) Silver nanoparticle-enhanced fluorescence in microtransponder-based immuno- and DNA hybridization assays. Anal Bioanal Chem, 398(5), 1993-2001. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2972226/pdf/nihms233120.pdf (free)

  4. Mandecki W, Ardelt B, Coadetti T, Davidowitz H, Flint JA, Huang Z, Kopacka WM, Lin X, Wang Z, Darzynkiewicz Z (2006) Microtransponders, the miniature RFID electronic chips, as platforms for cell growth in cytotoxicity assays. Cytometry A, 69(11), 1097-1105. http://onlinelibrary.wiley.com/doi/10.1002/cyto.a.20344/epdf (free)