Introduction to Fluorescence Modulation

The fluorescence modulation was shown to be reversible, with an increase of ≤20% with respect to the original value.

Interestingly, we observe very different pKa shift and fluorescence modulation within α-CD compared to β- cyclodextrin (β-CD).

By incorporating LNA bases into the (GT)15-DNA sequence, we create sensors that are not only more resistant towards undesirable fluorescence modulation in the presence of Ca2+ but that also retain their capabilities for the label-free detection of dopamine.

The stimuli-induced reversible proton transfer system is composed of materials that release or capture protons in response to stimuli and switch molecules that control color and/or fluorescence modulation by protons, and it is applied in stimuli-responsive materials and devices, including bistable electronic/electrochromic devices, electrofluorochromic devices, water-jet rewritable paper, visible-light-responsive rewritable paper, and mechanochromic materials.

Importantly, guest-responsive fluorescence modulation is evidenced through the remarkable turn-off sensing of the pesticide dichloran with admirable selectivity, a quick response time, and a very low LOD (124 nM), with sharp colorimetric changes under UV light.

For a photochromic spiro-diarylethene derivative (Spiro-DAE), its photocyclization reaction and multicolour fluorescence modulation performances were investigated based on a series of density functionals calculations in this work.

This short review is aimed at emphasizing the most prominent recent works devoted to the fluorescence modulation of organic fluorescent or fluorogenic molecules by electrochemistry.

The naturally occurring dark state in the parent YFPs yields strong fluorescence modulation upon long-wavelength-induced dark state depopulation, allowing selective detection at the frequency at which the long wavelength secondary laser is intensity modulated.

These well-controlled fluorescence modulation and photoswitching behaviours not only provide insights into interchromophoric interactions but also contribute to the development of stimuli-responsive luminescent macrocycles.

Excited state intramolecular proton transfer (ESIPT) mechanism-based solid state fluorescent materials showed unique photophysical properties such as a large Stokes shift and local environment (pH, polarity, ions and viscosity) responsive fluorescence modulation.

Here, we report ASAP3, a genetically encoded voltage indicator with 51% fluorescence modulation by physiological voltages, submillisecond activation kinetics, and full responsivity under two-photon excitation.

In the feedback mode of Scanning Electrochemical Microscopy (SECM), it is shown that the fluorescence modulation amplitude is sensitive to the nature of the substrate as well as to the tip-substrate distance and can thus be utilized to record optical approach curves.

Among various photophysical processes for fluorescence modulation, inner filter effect (IFE) is well-known for its simplicity and no requirement of the distances between the fluorophores and the corresponding modulators.

Reported herein is the application of cyclodextrin-promoted fluorescence energy transfer and fluorescence modulation to accomplish precisely such detection: the development of sensitive and selective florescence-based detection methods for phthalates in saliva, an easily collectable human biologic fluid.

The first manuscript “Turn-on Detection of Pesticides via Reversible Fluorescence Enhancement of Conjugated Polymer Nanoparticles and Thin Films” describes the detection of organochloride pesticides by monitoring the fluorescence modulation of conjugated polymer nanoparticles.

A detailed characterization of these two fluorescence modulations reveals that the initial fluorescence state of the labeled mediator (DNA) determines whether this mediator-conjugated dye undergoes PIFE or PIFQ upon protein binding.

Stimuli-responsive fluorescence switching is of great importance to fluorescence modulation in a wide range of applications, such as sensors, bioimaging, and displays.

TD-DFT calculations of the molecular Pourbaix sensors give insight into the mechanistic details of fluorescence modulation controlled by internal charge transfer (ICT) and photoinduced electron transfer (PET).

Is there any correlation between the extent of fluorescence modulation and the strength of the photoacid? Here, we used three photoacids: 2-naphthol (2OH, pKa* = 3.

Computational studies were performed to gain insights into the electronic energy level of the fluorophore and fluorescence modulation.

The sensor exhibited significant fluorescence modulation and chromogenic change with high Cu2+ sensitivity and selectivity over interfering metal ions.

We further exploited the tensile-dependent fluorescence modulation of the C-dot/polymer system to construct a tunable-intensity white light emitter, opening the way to innovative mechanically-tuned optical device.

Due to a high degree of fluorescence modulation (>270), good fatigue resistance and large fluorescence quantum yield, compound SyOTh 1 emerged as a candidate for single-molecule based super-resolution fluorescence microscopy.

This work paves an easy way to construct fully reversible multi-stimuli responsive fluorescence modulation smart materials.

We present developments in the design of synthetic near-infrared fluorescent nanosensors based on the fluorescence modulation of single-walled carbon nanotubes (SWNTs) with select sequences of surface-adsorbed N-substituted glycine peptoid polymers.

The effect of processing depth and NP thickness on fluorescence modulation is systemically investigated.

The present work epitomizes environment-sensitive fluorescence modulation of a prodigy, 4-(2-Hydroxyethyl)-10-phenyl-3,4,6,7,8,10- hexahydro-1H-cyclopenta[g]furo[3,4-b]quinoline-1-one (HPFQ) from the class of anti-cancer agent Azapodophyllotoxin, in differently charged model bio-mimetic micellar microenvironment of cationic CTAB, anionic SDS and neutral Triton X-100 using UV-visible absorption, steady state fluorescence, time-resolved fluorescence and fluorescence anisotropy studies.

This detection method uses cyclodextrin as a supramolecular scaffold to promote analyte-specific, proximity-induced fluorescence modulation of a high-quantum-yield fluorophore, which leads to unique fluorescence responses for each cyclodextrin-analyte-fluorophore combination investigated and enables unique pattern identifiers for each analyte using linear discriminant analysis (LDA).