Optimization of Rolling-Circle Amplified Protein Microarrays for Multiplexed Protein Profiling.

Protein microarray-based approaches are increasingly being used in research and clinical applications to either profile the expression of proteins or screen molecular interactions. The development of high-throughput, sensitive, convenient, and cost-effective formats for detecting proteins is a necessity for the effective advancement of understanding disease processes. In this paper, we describe the generation of highly multiplexed, antibody-based, specific, and sensitive protein microarrays coupled with rolling-circle signal amplification (RCA) technology. A total of 150 cytokines were simultaneously detected in an RCA sandwich immunoassay format. Greater than half of these proteins have detection sensitivities in the pg/ml range. The validation of antibody microarray with human serum indicated that RCA-based protein microarrays are a powerful tool for high-throughput analysis of protein expression and molecular diagnostics.

Comprehensive human genome amplification using multiple displacement amplification.

Fundamental to most genetic analysis is availability of genomic DNA of adequate quality and quantity. Because DNA yield from human samples is frequently limiting, much effort has been invested in developing methods for whole genome amplification (WGA) by random or degenerate oligonucleotide-primed PCR. However, existing WGA methods like degenerate oligonucleotide-primed PCR suffer from incomplete coverage and inadequate average DNA size. We describe a method, termed multiple displacement amplification (MDA), which provides a highly uniform representation across the genome. Amplification bias among eight chromosomal loci was less than 3-fold in contrast to 4-6 orders of magnitude for PCR-based WGA methods. Average product length was >10 kb. MDA is an isothermal, strand-displacing amplification yielding about 20-30 microg product from as few as 1-10 copies of human genomic DNA. Amplification can be carried out directly from biological samples including crude whole blood and tissue culture cells. MDA-amplified human DNA is useful for several common methods of genetic analysis, including genotyping of single nucleotide polymorphisms, chromosome painting, Southern blotting and restriction fragment length polymorphism analysis, subcloning, and DNA sequencing. MDA-based WGA is a simple and reliable method that could have significant implications for genetic studies, forensics, diagnostics, and long-term sample storage.