Abstract
Cross linked gold-dynamic constitutional frameworks (DCFs) are functional materials of potential relevance for biosensing applications, given their adaptivity and high responsivity against various external stimuli (such as pH, temperature) or specific interactions with biomolecules (enzymes or DNA) via internal constitutional dynamics. However, characterization and assessment of their dynamic conformational changes in response to external stimuli has never been reported. This study proves the capability of Surface Plasmon Resonance (SPR) assays to analyze the adaptive structural modulation of a functional matrix encompassing 3D gold-dynamic constitutional frameworks (Au-DCFs) when exposed to pH variations, as external stimuli. We analyze Au-DCFs formed from Au nano-particles, (AuNP) connected through constitutionally dynamic polymers, dynamers, with multiple functionalities. For increased generality of this proof-ofconcept assay, Au-DCFs, involving DCFs designed from 1,3,5-benzene-tricarbaldehyde (BTA) connecting centers and polyethylene glycol (PEG) connectors, are covalently attached to standard SPR sensing chips (Au nanolayers, carboxyl terminated or with carboxymethyl dextran, CMD toplayer) and analyzed using state-of-the art SPR instrumentation. The SPR effects of the distance 24 from the Au-DCFs matrix to the Au nanolayer of the sensing chip as well as of Au-DCFs thickness 25 were investigated. This study reveals the SPR response, augmented by the AuNP, to the confor-26 mational change, i.e. shrinkage, of the Dynamer & AuNP matrix when decreasing the pH and 27 provides an unexplored insight on the sensing applicability of SPR real-time analysis of adaptive 28 functional materials.