Multiresponsive Supramolecular Luminescent Hydrogels Based on a Nucleoside/Lanthanide Complex

Abstract

Supramolecular luminescent hydrogels based on natural molecules have shown high potential for a variety of applications because of unique optical properties and biocompatibility, particularly serving as advanced biomaterials for bioimaging, biosensing, cell engineering, and so forth. A lanthanide complex-based system provides a promising way to prepare supramolecular luminescent hydrogels. Herein, we realize the creation of a luminescent hydrogel assembled from lanthanides and nucleosides. Nucleosides, the essential components of nucleic acids, functioning as the ligands, successfully chelate with lanthanides and form complexes in water. The complexes subsequently serve as building-blocks to form supramolecular hydrogels, which exhibit characteristic luminescent emission of lanthanides. The coordination modes and forming mechanism are studied by electrospray ionization time-of-flight mass spectrometry, matrix-assisted laser desorption/ionization time of flight mass spectrometry, 1 H NMR spectroscopy, and Fourier transform infrared spectroscopy; the corresponding molecular simulations are presented, and macro-/micro-morphologies, mechanical properties, and luminescent performances of hydrogels are systemically studied. Remarkably, these luminescent hydrogels show fluorochromic properties in response to external stimuli, including pH, temperature, anions, and cations, which are thus adopted to design smart luminescent switches and detect specific species such as Cu 2+ . Our work provides a feasible strategy to prepare stimuli-responsive luminescent hydrogels, reveals the diverse potential of nucleoside-based hydrogels, and exhibits a novel pathway for the preparation of smart optical materials.

Sensitized Lanthanide Photoluminescence Based Sensors–a Review

“…Photoluminescent lanthanide derived hydrogels have advantages over conventional materials since they can be engineered for sensing applications in analytical, environmental, biological and medical fields [30,31] . During the past decade, a significant number of hydrogels based on macromolecules and low molecular weight gelators have been designed for sensing biologically or environmentally important molecules through sensitized lanthanide luminescence [32–34] . In this section, the sensing applications of hydrogels by means of sensitized lanthanide photoluminescent (PL) signal will be discussed.…”

Thermo-responsive light-emitting metal complexes and related materials

“…In addition to the thermal-activated non-radiative decay, many other factors may be activated or influenced by temperature, including the effective molecular conformation or configuration transformation of flexible systems, 61,62 the degree of inter-or intramolecular π-π stacking and metal-metal interactions existing in aggregates or clusters of Rh(I), Pt(II), Cu(I), Ag(I), and Au(I) complexes, 39,[63][64][65] the dynamic association or dissociation process of metal and lanthanide complexes, 66,67 phase transition, [68][69][70][71] the degree of inter-or intramolecular energy transfer of donor/acceptor systems, 72,73 as well as the thermal equilibrium of different excited states. 74,75 These mechanisms will be discussed in more detail in specific examples in the following chapters.…”

“…However, the emission intensity changes could also be caused by many other factors, such as the dynamic association/dissociation process or phase transition. 66,71 The shift of λ emi is another general readout during the studies of thermo-responsive materials, which could be a result of dynamic thermal-equilibrium of different excited states or the change of the energy/electron transfer efficiency. 76,77 The shift of λ emi often leads to the emission color changes of materials, allowing us to conveniently monitor the thermo-responsive process.…”

Research Progress Review of Preparation and Applications of Fluorescent Hydrogels

“…Ma research group of Tianjin University [45] reported a fluorescent hydrogel composed of lanthanide and nucleoside. Here, nucleosides, the main component of nucleic acids, act as ligands and successfully chelate with lanthanide elements to form complexes in water.…”