Hydrogel is a unique family of biocompatible materials with growing applications in chemical and biological sensors. During the past few decades, various hydrogel-based optical ion sensors have been developed aiming at point-of-care testing environmental monitoring. In this Perspective, we provide an overview research field including topics such as photonic crystals, DNAzyme cross-linked hydrogels, ionophore-based sensing fluoroionophore-based optodes. As different principles are summarized,...

Bulk optode-based ion selective optical sensors work on the basis of extraction equilibria, and their response toward analyte is known to dependent sample pH. This pH dependence has been one major disadvantages that have hampered broad acceptance bulk optodes in chemical sensing. We present here for first time use exhaustive Ca(2+)-selective nanosensors may overcome this response. The were characterized at different same linear calibration was obtained Ca(2+) concentration range from 10(-7)...

Ion selective optical sensors are typically interrogated under conditions where the sample concentration is not altered during measurement. We describe here an alternative exhaustive detection mode for ion sensors. This sensor concept demonstrated with ionophore-based nanooptodes either calcium or polycationic heparin antidote protamine. In agreement a theoretical treatment presented here, linear calibration curves were obtained in instead of sigmoidal equilibrium-based The response range...

The sensing mechanism of fluorescent ion-selective nanosensors incorporating solvatochromic dyes (SDs), with K+ as model ion, is shown to change a function dye lipophilicity. Water-soluble SDs obey bulk partitioning principles where the sensor response directly depends on lipophilicity SD and exhibits an influence phase volume ratio aqueous solution (dilution effect). A lipophilization overcome these limitations. An interfacial accumulation proposed confirmed Förster resonance energy...

Focusing on ionophore-based ion-selective electrodes (ISEs), this work highlights recent advances in increasing sensor sensitivity by converting potentiometric response to a variety of electrical and optical signals including charge, current, luminescence, color change.

Fluorescent probes based on boron dipyrromethene functionalized with a phenylboronic acid group (BODIPY–PBAs) were synthesized in high yield for the first time by Suzuki coupling of bis(pinacolato)diboron and 8-(4-bromophenyl)-1,3,5,7-tetramethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY). Wavelength tuning fluorophores was achieved attaching an auxochromic substituent to 5-position BODIPY core structure through Knoevenagel condensation. The emission intensity increases when binding...

To enrich the recipes of ion-selective nanosensors, graphene quantum dots (GQDs) were integrated into ionophore-based fluorescent nanosensors with exquisite selectivity and high sensitivity for Na+ K+. The unique property GQDs gave ultrasmall size (ca. 10 nm), brightness, good biocompatibility, potential pH sensing possibility. At 7.4, sensors exhibited a detection range from 0.1 mM to 1 M 3 μM successfully applied blood serum urine samples. Chemically induced intracellular sodium...

Nanoscale ionophore-based ion-selective optodes (nano-ISOs) are effective sensing tools for in situ and real time measurements of ion concentrations biological environmental samples. While searching novel materials, nano-ISOs free plasticizers particularly important applications. This work described plasticizer-free based on Si-containing particles including PEGylated organosilica nanoparticles, PDMS nanospheres, SiO2 microspheres, with diameters around 50 nm, 100 5 μm, respectively. The...

We report here a rapid and versatile metal ion analytical platform based on the dye release from hydrogels entrapping ion-selective microdroplets. Using Ca2+, Pb2+, Na+ as model ions, were developed in combination with four positively charged dyes, making highly promising for point-of-care diagnostics well environmental monitoring.

Fluorescence barcoding with multicolor fluorophores is limited by spectral crowding. Herein, we propose a fluorescence encoding method in single-color channel photoswitches. The photochromic naphthopyran was used to mediate the of polystyrene microspheres through resonance energy transfer. initial intensity (F0) and after UV light activation (F/F0) were combined generate hundreds 2-dimensional barcodes. coding capacity further expanded different chemical kinetics photoswitch-based barcodes...

A dual-functional fluorescent nanosensor to monitor lysosomal Cl − and HClO concentration changes is presented here for the first time.

Microscopic temperature imaging holds significant importance in various fields, particularly the development of nanomaterials for photothermal therapy (PTT). In this study, we present an analytical method to probe cellular based on chemical kinetics and additional luminescence quenching by photoswitchable naphthopyrans. Taking advantage rapid ring-closing reaction naphthopyran, sensing was realized with a linear relationship between logarithmic decay time constant (ln τ) reciprocal (

A visible light responsive photoswitch promising for the chemical sensing of fluoride and hydroxide anions.

Potentiometric sensors require the implementation of conducting wires for signal transduction, but this is impractical readout individual nanoparticles. It here demonstrated first time that potentiometric response ion-selective nanospheres can be observed with voltage-sensitive dyes, thereby converting nanoscale electrochemical signals into an optical readout. No reference electrode needed since by fluorescence. The results strongly support origin fluorescence response. exhibit excellent...

Ion-selective microspheres based on surface modification of polystyrene particles (0.8 and 2.4 μm, diameter) are presented here for the first time. The traditional lipophilic sensing components K(+) selective optodes (chromoionophore, ion-exchanger ionophore) adsorbed using a simple mixed solvent method. resulting microparticles respond to in an exhaustive mode with excellent selectivity rapid response time (t95% = 5 s).

A simple and novel method is proposed here for the first time to determine pKa values of chromogenic hydrophobic pH sensitive probes directly in nanospheres. can be obtained by measuring response nanospheres (containing ion exchanger) followed Na+ responses solvatochromic dyes exchanger). The four chromoionophores were successfully determined. This principle also applicable characterize colorimetric other water immiscible nanomaterials.

While the titrimetric assay is one of most precise analytical techniques available, only a limited list complexometric chelators as many otherwise promising reagents are not water-soluble. Recent work demonstrated successful titrimetry with ion-exchanging polymeric nanospheres containing hydrophobic complexing agents, so-called ionophores, opening an exciting avenue in this field. However, method was to ionophores very high affinity analyte and exhibited relatively titration capacity. To...

We present here an innovative platform for the determination of pH buffer capacity based on FITC-dextran loaded hydrogels. Optical signals from pH-sensitive hydrogels were analyzed by simple parameters including distance and color change. The methodology was validated five different systems exhibited wide linearity (0.1 to 100 mM), good batch-to-batch reproducibility, high versatility, resistance background ionic strength changes. Experimental results also fit well with a theoretical model...

Demand for rapid quantitation of polyions such as heparin and protamine are ever growing. Previous paper-based polymeric optical electrochemical sensing devices required more than several hours signal stabilization. Therefore, signals were acquired with fixed sample exposure time modes, which was time-consuming technically demanding. We present here the first detection in equilibrium mode emulsified nanospheres. The method significantly shortens response from to typically less 10 s offers...

Liao's photoacids (PAs) are a well-known type of visible light-responsive photoswitches. Here, taking advantage the temperature-dependent thermal relaxation from ring-closed to ring-opened forms, PAs proposed for first time as fluorescent temperature sensor in cells. The logarithmic lifetime (ln τ) spiro-form exhibited an excellent linear response reciprocal temperature. In addition, were able highlight lysosomes and responded lysosomal pH changes. These properties made promising probes...

A boronic acid functionalized aza-borondipyrromethene dye (azaBDPBA) was applied to the dual-wavelength detection of hydrogen peroxide with high selectivity, which loaded into cells indicate alteration intracellular during biological processes.

Chelators and end point indicators are the most important parts of complexometric titrations.

A reversible and pH-independent fluorescent ion optode is introduced with an ionophore surface confined solvatochromic dye transducer doped onto microporous nylon membranes.