title: Non-covalent interactions in controlling pH-responsive behaviors of self-assembled nanosystems.
abstract: Self-assembly and associated dynamic and reversible non-covalent interactions are the basis of protein biochemistry (e.g., protein folding) and development of sophisticated nanomaterial systems that can respond to and amplify biological signals. In this study, we report a systematic investigation of non-covalent interactions that affect the pH responsive behaviors and resulting supramolecular self-assembly of a series of ultra-pH sensitive (UPS) block copolymers. Increase of hydrophobic and π-π stacking interactions led to the decrease of pKa values. In contrast, enhancement of direct ionic binding between cationic ammonium groups and anionic counter ions gave rise to increased pKa. Moreover, hydration of hydrophobic surfaces and hydrogen bonding interactions may also play a role in the self-assembly process. The key parameters capable of controlling the subtle interplay of different non-covalent bonds in pH-triggered self-assembly of UPS copolymers are likely to offer molecular insights to understand other stimuli-responsive nanosystems. Selective and precise implementation of non-covalent interactions in stimuli-responsive self-assembly processes will provide powerful and versatile tools for the development of dynamic, complex nanostructures with predictable and tunable transitions.
authors.affiliation: Department of Pharmacology, Simmons Comprehensive Cancer Center.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Pharmacology, Simmons Comprehensive Cancer Center.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Pharmacology, Simmons Comprehensive Cancer Center; Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wei
authors.affiliation: Department of Pharmacology, Simmons Comprehensive Cancer Center.
authors.forename: Min
authors.initials: M
authors.lastname: Luo
authors.affiliation: Department of Pharmacology, Simmons Comprehensive Cancer Center.
authors.forename: Gang
authors.initials: G
authors.lastname: Huang
authors.affiliation: Department of Otolaryngology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390.
authors.forename: Baran D
authors.initials: BD
authors.lastname: Sumer
authors.affiliation: Department of Pharmacology, Simmons Comprehensive Cancer Center.
authors.forename: Jinming
authors.initials: J
authors.lastname: Gao