A new self-assembling gel medium for protein arrays provides more stability for a greater variety of proteins with less preparation time than current arrays require, according to Japanese protein engineer Itaru Hamachi, lead author on a paper published in the Dec. 7 online edition of Nature Materials.
“Our hydrogel consists of a small molecule so that it self-assembles into hydrogel spontaneously,” Hamachi told ProteoMonitor. “[P]olymerization or extra treatment is never needed to obtain a hydrogel state.” This is a step up from existing offerings such as the HydroGel substrate manufactured by PerkinElmer, Hamachi said, in its avoidance of polymerization steps as well as its especially low gelator concentration, which Hamachi said made it a “comfortable” environment for more proteins.
PerkinElmer’s Amy McCann, global product manager, array processing, acknowledged that a polymerization step was needed for HydroGel, but noted that since the product was sold as a pre-coated slide, customers did not need to spend time doing it themselves.
Using a semi-wet material such as a gel as a medium for arrayed proteins has obvious advantages over dry-spotted arrays, in which proteins can easily degrade. Aside from stabilizing proteins, it immobilizes them in a 3D environment and provides a medium to facilitate reactions of the arrayed proteins or peptides with substrates — although, Hamachi noted, the diffusion rate is more limiting than that in a liquid environment. Hamachi’s gel, which consists of a glycosylated amino acid scaffold, also has an amphiphilic structure when assembled. The result is the creation of both an aqueous cavity in which an arrayed protein can react with a substrate, as well as hydrophobic domains to which a more hydrophobic product could migrate, allowing for easy monitoring of the reaction. His group did a proof of principle experiment that showed that this could work for monitoring protease reactions, and Hamachi said that projects were in the works for developing similar arrays for looking at other enzymes, as well as other types of protein-protein interactions such as membrane protein-mediated signal transduction interactions.
Although Hamachi has not yet made any deals to commercialize the product, he added that he is looking to do so, and hopes to collaborate with other companies or groups on his upcoming projects.