Novel Fluorescent Microemulsion: Probing Properties, Investigating Mechanism, and Unveiling Potential Application

Abstract

Nanoscale microemulsions have been utilized as delivery carriers for nutraceuticals and active biological drugs. Herein, we designed and synthesized a novel oil in water (O/W) fluorescent microemulsion based on isoamyl acetate, polyoxyethylene castor oil EL (CrEL), and water. The microemulsion emitted bright blue fluorescence, thus exhibiting its potential for active drug detection with label-free strategy. The microemulsion exhibited excitation-dependent emission and distinct red shift with longer excitation wavelengths. Lifetime and quantum yield of fluorescent microemulsion were 2.831 ns and 5.0%, respectively. An excellent fluorescent stability of the microemulsion was confirmed by altering pH, ionic strength, temperature, and time. Moreover, we proposed a probable mechanism of fluorochromic phenomenon, in connection with the aromatic ring structure of polyoxyethylene ether substituent in CrEL. Based on our findings, we concluded that this new fluorescent microemulsion is a promising drug carrier that can facilitate active drug detection with a label-free strategy. Although further research is required to understand the exact mechanism behind its fluorescence property, this work provided valuable guidance to develop new biosensors based on fluorescent microemulsion.

Preparation of α-Linolenic-Acid-Loaded Water-in-Oil-in-Water Microemulsion and Its Potential as a Fluorescent Delivery Carrier with a Free Label

“…On the basis of our previous study, the spectroscopy and fluorescence intensity of ALA-loaded O/W and W/O/W microemulsion were investigated; afterward, the results were displayed in panels a and b of Figure . The tendency of emission spectra in microemulsion was consistent with the measurements by Hou at al . Indeed, the mass fraction of Cremophor EL was closely related to the fluorescence intensity of the microemulsion.…”

“…Our previous investigation presented a compelling argument for the formulation of a label-free, biodegradable, and safe fluorescent probe based on the synthesized O/W fluorescent microemulsion. 23 That investigation proved that the concentration of surfactant exhibited a correlation to the fluorescence intensity. 24 On the basis of this fascinating phenomenon, we propose that W/O/W microemulsion equipped with a multiple-layered interfacial structure would have a larger specific surface area to impel the interaction of the surfactant and water, which could exhibit a stronger and stable fluorescence in contrast to O/W microemulsion.…”

“…In our previous work, it has been demonstrated that ALA in ALA-loaded O/W microemulsion inserted into a water–oily interfacial monolayer. , We propose that W/O/W microemulsion equipped with multicompartments could disperse ALA into multiple water–oily interfaces, so that sensitive ALA in the internal layer has a lesser probability to become oxidized. Our previous investigation presented a compelling argument for the formulation of a label-free, biodegradable, and safe fluorescent probe based on the synthesized O/W fluorescent microemulsion . That investigation proved that the concentration of surfactant exhibited a correlation to the fluorescence intensity .…”

Emulsion Techniques for the Production of Pharmacological Nanoparticles

“…Microemulsion droplet sizes are well below 100 nm . Hou et al designed the novel fluorescent microemulsion for delivery of nutraceuticals and active biological drugs using microemulsion method . Microemulsion was prepared with isoamyl acetate (oil phase), polyoxyehtylene castor oil EL (CrEL) (surfactant), and water.…”

“…[34] Hou et al designed the novel fluorescent microemulsion for delivery of nutraceuticals and active biological drugs using microemulsion method. [35] Microemulsion was prepared with isoamyl acetate (oil phase), polyoxyehtylene castor oil EL (CrEL) (surfactant), and water. The prepared microemulsions could emit bright blue fluorescence due to aromatic ring structure of polyoxyethylene ether substituent of CrEL in hydrophobic com ponents, suggesting the potential for active drug detection for biosensor applications.…”