(74a) A Smart Material with Both Sticky and Non-Sticky Properties

“Non-sticky” and “sticky” properties are two highly desired material characteristics. The presence of both is required for numerous applications. The former refers to the ability to resist non-specific biomolecular (or cellular) adhesion while the latter refers to the chemical reactivity, allowing for covalent attachment of recognition elements (e.g. antibodies). However, from conventional wisdom, these two distinct properties cannot exist within a “single” material. For example, most non-fouling materials must either be reacted to introduce functionalizable groups (e.g. carboxylate moieties) or reacted with coupling agents (e.g. carbodiimides) for conjugation to targeting ligands. For the first time, we propose an answer to this challenge.

By mimicking the drug camptothecin, we introduced a new zwitterionic material capable of switching between two equilibrium states, each with its own unique property: a lactone-ring structure (CB-Ring) and an acidic open-ring structure (CB-OH). We found that the zwitterionic nature of CB-OH make the material ultra-low fouling to complex media while the CB-Ring structure allow for reactivity with nucleophiles (e.g. amines). Control over these two material states (or properties) can be obtained via an acid/base driven equilibrium. In addition, we demonstrated a proof-of-concept experiment to realize a high throughput antibody array for early cancer diagnostics, in a simple way, by taking advantage of this novel smart material.