Design, Synthesis, Investigation, and Application of a Macromolecule Photoswitch

Abstract

Azobenzene (AZO) has attracted increasing interest due to its reversible structural change upon a light stimulus. However, poor fatigue durability and the photobleaching phenomenon restricts its further application. Herein, the AZO domain as a pendent group, was incorporated into copolymers, which was synthesized by radical copolymerization in the research. Structure-properties of synthesized copolymer can be adjusted by monomer ratios. Emphatically, responsive properties of copolymer in different solutions were investigated. In the DMSO solution, copolymer exhibited effective structural change, stable rapid responsive time (1 min) upon UV light at room temperature, stable relative acceptable recovery time (100 min) upon white light at room temperature, and good fatigue resistance property. In an aqueous solution, even more controllable responsive properties and fatigue resistance properties for copolymer were verified by results. More pervasively, the recovery process could be controlled by light density and temperature. In order to clarify reasons for the difference between the AZO molecule and the AZO domain of copolymer, energy barrier or interactions between single atoms or even structural units was calculated using the density functional theory (DFT). Furthermore, the status of copolymer was characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). Finally, copolymer was further functionalized with bioactive protein (concanavalin, ConA) to reduce the cytotoxicity of the AZO molecule.

Fabrication, Investigation, and Application of Light-Responsive Self-Assembled Nanoparticles

“…HANN copolymer was synthesized by copolymerization of functional monomers including HEMA, double carbon modified NHS (NAS), NVP and double carbon modified AZO, the structure of HANN was characterized in detail in our previous work (Pang et al, 2019). Briefly, AZO and NAS monomer was synthesized by acylchlorination.…”

“…In order to improve the performance of photo switches in aqueous environments, and decrease photo switch cytotoxicity, copolymer and polysaccharide derivatives with azobenzene pendent groups were designed, respectively, in our previous work. The former showed a more controllable light-response and light-recovery performance in an aqueous environment (Pang et al, 2018, 2019).…”

Development of Light-Responsive Poly(γ-Benzyl-L-Glutamate) as Photo Switches by a One-Step NCA Method

“…In recent decades, as a kind of stimuli-response material, photo switches have become new favorites in fields that require switching effects, including information science and chemical sensing due to structural changes in light. As a member of the photo switches, azobenzene (AZO) possesses two different reversible isomers (trans and cis) (Beharry and Woolley, 2011 ; Bian et al, 2016 ; Michael Kathan, 2017 ; Chen et al, 2018 ; Lerch et al, 2018 ; Pang et al, 2018 , 2019 ). The reversible isomerization could be realized upon light excitation and thermal transition.…”

“…The reversible isomerization could be realized upon light excitation and thermal transition. But the thermal transition is influenced by either the external environment or internal structure of the AZO family, which bring problems of photobleaching, instability, and uncontrollability (Pang et al, 2018 , 2019 ). In order to overcome problems, measures of substitute modifying, grafting, copolymerization, and immobilization have been used to improve the stability and controllability including our previous studies (Deka et al, 2015 ; Liu et al, 2015 ; Lin et al, 2016 , 2017 ).…”

“…In order to overcome problems, measures of substitute modifying, grafting, copolymerization, and immobilization have been used to improve the stability and controllability including our previous studies (Deka et al, 2015 ; Liu et al, 2015 ; Lin et al, 2016 , 2017 ). Based on previous research, the long chains of polymers would help to increase the stability and controllability of thermal transition (Pang et al, 2018 , 2019 ). Therefore, designing an AZO-functionalized polypeptide would provide a kind of practical photo switch for its application in bio-related fields.…”