Polymers possessing secondary/tertiary structure

In addition to this secondary structure, polymers possess a tertiary structure. In the case of proteins, the tertiary structure describes the way in which the helix is folded around itself. 

Figure 2.10 Several models for the polymers possessing secondary or tertiary structure.

Protein microarrays are very similar to DNA microarrays however, they are much more difficult to design [4]. DNA is an unstructured linear polymer that hybridizes due to information contained in the nucleic acid sequence. Proteins, however, are much more complex and possess a wide degree of secondary, tertiary, and quaternary structures. In addition, protein function is highly dependent on protein structure. As a consequence, protein microarrays must be synthesized in a way that prevents denaturing of the molecule. Maintaining proteins in buffers at appropriate temperatures and pH is crucial in... 

Polyethylenimine (PEI) is the most outstanding example for synthetic cationic polymers because of its wide range of applications. It can be synthesized in linear (LPEI) as well as in branched (BPEI) structures. LPEI possesses primary and secondary amino groups, whereas BPEI also features tertiary amino groups. BPEI usually has a ratio of primary to secondary to tertiary amino functionalities of 1 2 1 and up to 25% of these amino groups are protonated under physiological conditions. Such buffer capability can also be utilized for endosomal escape mechanisms. The amino... 

Ethyleneimine, which possesses the same tight structure as ethylene oxide, polymerises easily through a cationic mechanism. As the detailed mechanism is quite complex, poly(ethyleneimine) (PEI) is usually a branched polymer containing primary, secondary and tertiary amine groups in the approximate ratio 1 2 1. Synthesis by cationic polymerisation of linear PEI designed to be used for gene delivery has been reported. 

---