Spontaneous Counterion‐Induced Vesicle Formation: Multivalent Binding to Europium(III) for a Wide‐Range Optical pH Sensor

Abstract

A counterion‐directed molecular design strategy is described for the spontaneous formation of stable vesicles via readily available imidazolium salts with the EDTA counterion in aqueous media. The counteranion is employed to adjust the balance between hydrophobic and hydrophilic parts, which satisfies the requirement of packing parameter for vesicle formation. The counterion‐induced vesicles (CIVs) feature spontaneous formation, simple preparation, and easy availability of surfactants. Importantly, the unusual counterion‐induced vesicle‐like sphere aggregates can further chelate europium(III) ions to enhance the europium‐centered emission in aqueous media and make it viable for an optical pH sensor, which exhibits a linear response in a wide range of pH values from 3 to 11. To the best of our knowledge, this constitutes one of the widest ranges of Eu‐based pH sensors reported so far. This design concept has offered a new avenue for the preparation of functional vesicles.

Selective Metal-Ion-Mediated Vesicle Adhesion Based on Dynamic Self-Organization of a Pyrene-Appended Glutamic Acid

“…During the last decade, self-assembled vesicles have been designed to detect pH, biomolecules like saccharide or adenosine triphosphate (ATP), biohazardous agents like reactive oxygen species (ROS), and so on [18][19][20][21][22]. Synthetic vesicles or liposomes have also been developed for detecting metal ions 26.…”

“…In spite of biomimetic aspect, many vesicle systems were designed to be sensors to facilitate the afterward applications. [18][19][20][21][22] For instance, although single molecular fluorescent sensors without selfassembly capability can be designed into biocompatible and be applied in sensing analyses in living cells or tissues, it is quite hard to achieve the theranostic functions or combined therapy. 23,24 However, drug release behaviors of vesicular drug carrier with sensing function in vivo can be visually guided according to the optical changes in specific environments.…”

Programmable Nanoassemblies from Non‐Assembling Homopolymers Using Ad Hoc Electrostatic Interactions

“…This assertion was inspired by the observations that the packing of small molecule surfactants can be significantly altered due to the presence of multivalent counterions. [6] This also should not be confused with polyionic complexes that concerns the co-assembly of two oppositely charged block polyelectrolytes. [7] Although self-assembly of amphiphilic homopolymers itself has been a subject of recent interest and thus reviews, [8] the possibility of directing a non-assembling homopolymer to self-assemble using electrostatic driving forces has not been studied to our knowledge.…”

Light‐ and Humidity‐Induced Motion of an Acidochromic Film

“…[1][2][3][4][5] If applied to the design of artificial, biomimetic smart materials,t he mechanistic principles of this phenomenon could contribute to specific applications that require optical camouflage,f or instance within the context of security and defense. [20][21][22][23][24][25][26] However,p ractical obstacles,s uch as difficulties with the handling and fabrication of macroscopic devices as well as safety concerns,l imit the usefulness of liquid acidochromic materials.E mbedding pH-responsive components into polymer matrices is ac onvenient approach to sensing materials that are devoid of fatigue and have reasonably short response times. [10][11][12][13][14][15][16][17][18][19] Acidochromism, that is,p H-induced color modulation, is of importance in the design of pH sensors.…”

“…[6][7][8][9] Rapid changes in color (chromism) can be induced by changes in temperature,pressure,pH, or ionic strength, or by interaction with light. [13,15,[20][21][22][23][24][25][26] Afast-forward strategy to high capacities in the rapid and reversible uptake of water could be the use of hydrogels as swelling matrices. [20][21][22][23][24][25][26] However,p ractical obstacles,s uch as difficulties with the handling and fabrication of macroscopic devices as well as safety concerns,l imit the usefulness of liquid acidochromic materials.E mbedding pH-responsive components into polymer matrices is ac onvenient approach to sensing materials that are devoid of fatigue and have reasonably short response times.…”