 Short peptides are more advantageous because, unlike the long chains that fold randomly upon adsorption causing the active protein domains to be sterically unavailable, short peptides remain stable and do not hide the receptor binding domains when adsorbed.Another advantage to short peptides is that they can be replicated more economically due to the smaller size.A bi-functional cross-linker with a long spacer arm is used to tether peptides to the substrate surface.