Dual Photo- and pH-Responsive Spirooxazine-Functionalized Dextran Nanoparticles

Abstract

A dual photo- and pH-responsive spirooxazine-functionalized polymer was synthesized by functionalization of dextran with a spirooxazine derivative (SO-COOH). The functionalized dextran derivatives can form nanoparticles in aqueous medium. Under UV light irradiation, the spirooxazine-functionalized dextran (Dex-SO) nanoparticles isomerize to zwitterionic merocyanine-functionalized dextran (Dex-MC), which leads to aggregation. However, the process is reversible upon irradiation with visible light. Under acidic conditions, the hydrophobic spirooxazine is protonated, and the nanoparticles aggregate or swell at pH values of 5 or 3, respectively. The encapsulation of the hydrophobic fluorescent dye Nile Red as model drug allowed us to gain more information about the structural changes under stimulation of UV light and acid treatment.

Preparation of waterborne polyurethane film based on spirooxazine containing hydrophilic groups

“…Compared with others, spirooxazine has been extensively studied because of its good fatigue resistance, good thermal stability of the ring‐opening body, and less influence by the polarity of the solvent 10–12 . Recently, Rahimi used spirooxazine derivatives to functionalize dextran to prepare a dual photosensitive and pH‐responsive spirooxazine functionalized polymer 13 . Sun reported a polyurea (PU) microcapsule containing spirooxazine, which shows higher energy storage efficiency than microcapsules without spirooxazine 14 …”

An anticounterfeiting strategy based on photochromic nonwoven polyester fabric by plasma‐assisting spray coating with ultraviolet‐responsive silica@strontium aluminate nanoparticles

“…Microencapsulation has been employed to enhance the colorant stability and photochromism; however, the finished fibers become harsher and stiffer to result in lower comfort properties. [17] Various persistent photoluminescent pigments were presented as distinct primary color emitters like Y 2 O 2 S: Eu 3+ ,Mg 2+ as red emitter, [18] SrAl 2 O 4 :Eu 2+ ,Dy 3+ as greenish emitter, [19] and CaAl 2 O 4 :Eu 2+ ,Nd 3+ as bluish emitter. [20] The lanthanide-doped aluminates have proved to be one of the best persistent photoluminescent pigments due to their brightening characteristics, high phototability, nontoxicity, nonradioactivity, chemical stability, and recyclability.…”

“…Microencapsulation has been employed to enhance the colorant stability and photochromism; however, the finished fibers become harsher and stiffer to result in lower comfort properties. [ 17 ]…”

Preparation and properties of a polyurethane film based on novel photochromic spirooxazine chain extension

“…In contrast to inorganic materials, organic photochromic molecules change their molecular structure during the reversible photochromic process, resulting in distinct chemical and physical properties, 6,7 such as their polarity, refractive index, electrolyte constant, conductivity, phase transfer, solubility, and viscosity. 8,9 According to their special properties, organic photochromic molecules are usually applied in optical data, [10][11][12] molecular logic gates, photoelectric switches, 13,14 security documents, 15,16 chemical sensors, 17,18 medicine, 19 biotechnology, 20 self-cleaning, 21 and other fields with broad application prospects. Shin et al designed and synthesized the spiropyran conjugated polyethylene glycol lipid compound [0Sp6]-NHS, which is safe and non-toxic.…”

“…24 Among the different types of organic photochromic molecules, spirooxazine compounds have become a very attractive light trigger due to their fast response speed, re-erasable nature, and high sensitivity. 9 By absorbing the energy of UV light, the structure of the colorless closed ring (SO) which is non-polar orthogonal can be photo-excited to the blue open ring which has a polar plane structure (PMC) ascribed to the breakage of the C spir –O bond on the spirooxazine ring. Under visible light irradiation, the C spir –O bond on the oxazine ring is reconnected, and the PMC form is converted back to the initial SO state.…”