Synthesis and Characterization of Photoresponsive Macromolecule for Biomedical Application

Abstract

Azobenzene, a photo switcher, has attracted increasing interest due to its structural response to photo stimulus in the field of information science and chemical sensing in the recent decades. However, limited water solubility and cytotoxicity restrained their applications in the biomedical field. In research, HA-AZO has been designed as a water soluble photo switcher in biomedical application. Synthesized HA-AZO had good water-solubility and a stable π-π* transition absorbance peak trans-isomer. With exposure to UV, transformation from trans-isomer to cis-isomer of HA-AZO could be realized according to UV spectra. Reversely, trans-isomer could be gradually recovered from cis-isomer in the dark. Simultaneously, quick response and slow recovery could be detected in the process of structural change. Moreover, repeated illumination was further used to detect the antifatigue property of HA-AZO, which showed no sign of fatigue during 20 circles. The influence of pH value on UV spectrum for HA-AZO was investigated in the work. Importantly, in acid solution, HA-AZO no longer showed any photoresponsive property. Additionally, the status of HA-AZO under the effect of UV light was investigated by DLS results and TEM image. Finally, in vitro cytotoxicity evaluations were performed to show the effects of photoresponsive macromolecule on cells.

Design, synthesis, and investigation of a visible light-driven photo-switching macromolecule

“…Numerous attempts have been made to increase the thermostability of the cis form, including the immobilization of AZO onto material surfaces, graing of AZO to a macromolecule, copolymerization, and cyclization. 2,4,6,8,9 Similar to these studies, we designed a polysaccharide derivative and AZO copolymers as photoswitches, and found that the thermostability of the cis form could be improved and controlled by environmental parameters as well as structural parameters such as temperature, light density, solvent, and chain characteristics. 9 Although these progresses have realized the application of AZOs as photo-switches, ultraviolet band excitation source has some disadvantages in extending the applications of smart molecules.…”

“…7 Moreover, the photobleaching phenomenon was also found in the small AZO molecule derivatives. 8 These drawbacks restrict their application as photo-switches. Numerous attempts have been made to increase the thermostability of the cis form, including the immobilization of AZO onto material surfaces, graing of AZO to a macromolecule, copolymerization, and cyclization.…”

Norbornene-Functionalized Chitosan Hydrogels and Microgels via Unprecedented Photoinitiated Self-Assembly for Potential Biomedical Applications

“…9 Light is a very attractive stimulus as it provides an additional spatio-temporal control over the selfassembly process, 3 however, examples of light-triggered supramolecular materials are mostly limited to the photo-switchable azobenzene moiety, alone or in cyclodextrin inclusion complexes, 10 and are known to lack stability due to the retro-isomerisation of azobenzene under physiological conditions. 11 Examples of photo-initiated self-assembled polysaccharide hydrogels and materials are rare, with few examples using azobenzene-functionalised hyaluronic acid, 12 cellulose, 13 xylan 14 or dextran. 15 The development of polysaccharide-based materials has been a very active area of research over the last few years, mainly owing to their low-cost, abundancy, non-toxicity, and natural bioactivity.…”

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 ).…”