Imagine what you could accomplish with an extra pair of hands. And what about another pair of eyes? While the concept sounds like science fiction, the reality is that you can stretch your productivity with the newest life science instruments and reagents. Ingenious technologies literally allow you to do and see more. You can maximize every assay and every hour you spend at the bench.
Now a verb, multiplexing describes the act of simultaneously performing hundreds or thousands of assays, and simultaneously investigating the presence of more than one analyte. The efficiency is a stark contrast to several years ago, when researchers had no choice but to screen for one analyte at a time. Much like searching for that proverbial needle in a haystack, the tedious task not only required time, but also excessive use of disposable labware and consumables. Now the job can be completed within hours using as little as one 96-well microplate.
Time is not the only advantage of multiplexing. The strategy allows researchers to acquire a bird’s eye view of gene or protein expression and the personalized signatures of disease—such as the “immense natural heterogeneity in tumor phenotypes, disease outcomes, and response to therapies,” according to a paper published in the May 2006 issue of Genome Research1. The new multiplexing technologies “facilitate an understanding of the disease mechanisms,” according to the paper, putting researchers on the right track to developing effective therapies. “The dimension and complexity of such data provide opportunity to uncover patterns and trends that can distinguish subtle phenotypes in ways that traditional methods cannot.”
Central to multiplexing technologies are sophisticated dyes and the imaging systems that can detect the various colors. Each antibody or small molecule probe can carry a different color. To test for 10 analytes, for example, you can add antibodies to all 10 in the same well. The detected colors indicate which antibodies have bound to certain analytes. Improving chemical and imaging know-how is allowing for greater sensitivity, specificity, and stability. The advancements are especially useful with low abundance proteins, which are proving to be highly important in the cellular world.
Beads created by Luminex are now among the most popular multiplex tools. The company developed a set of 100 beads, each with a unique ratio of red dye to infrared fluorescent dye, creating a distinct spectral signature. After tethering a different fluorescent antibody or other binding substrate to each of the 100 beads, you can incubate an entire set with one sample in the well of a microplate. The complement of analytes is determined by detecting and analyzing the various fluorescent signals generated.
Making your own beads allows you to customize your experiments; however, you may also want to consider the convenience of kits that provide beads or other solid substrates that already feature specific binding substrates. You can find assays that have a set of beads designed to study cytokines, other groups of signaling molecules, proteins involved with certain diseases, and other sets of biomarkers. Some companies also offer custom services.
Take a look at the list below for some very real possibilities, and leave the science fiction to movies and literature.
1M West et al, “Embracing the complexity of genomic data for personalized medicine,” Genome Research, 16(5):559-566, May 2006.
With this system and the Luminex® 100™ analyzer, you can measure multiple analytes in a single 50 µl aliquot of serum, plasma, or cell culture supernatant. These kits are subject to the same development, validation, manufacturing, and quality control standards as our Quantikine® ELISAs. The result is the most accurate, sensitive, and reproducible cytokine multiplex assay available. Each sample type is evaluated and validated on the following performance characteristics: sensitivity, precision, recovery, sample linearity, specificity, and the ability to recognize both the natural and recombinant analyte. Further, all analytes are tested together as a panel to ensure multiplex compatibility.
