Fluorescent Nanosensors for Intracellular Chemical Analysis:  Decyl Methacrylate Liquid Polymer Matrix and Ion-Exchange-Based Potassium PEBBLE Sensors with Real-Time Application to Viable Rat C6 Glioma Cells

Abstract

Fluorescent spherical nanosensors, or PEBBLEs (probes encapsulated by biologically localized embedding), in the 500 nm-1 microm size range have been developed using decyl methacrylate as a matrix. A general scheme for the polymerization and introduction of sensing components creates a matrix that allows for the utilization of the highly selective ionophores used in poly(vinyl chloride) and decyl methacrylate ion-selective electrodes. We have applied these optically silent ionophores to fluorescence-based sensing by using ion-exchange and highly selective pH chromoionophores. This allows the tailoring of selective submicrometer sensors for use in intracellular measurements of important analytes for which selective enough fluorescent probes do not exist. The protocol for sensor development has been worked out for potassium sensing. It is based on the BME-44 ionophore (2-dodecyl-2-methyl-1,3-propanediylbis[N-[5'nitro(benzo-15-crown-5)-4'-yl]carbamate]). The general scheme should work for any available ionophore used in PVC or decyl methacrylate ion-selective electrodes, with minor adjustments to account for differences in ionophore charge and analyte binding constant. The reversible and highly selective sensors developed have a subsecond response time and an adjustable dynamic range. Applications to live C6 glioma cells demonstrate their utility; the intracellular potassium activity is followed in real time upon extracellular administration of kainic acid.

Potassium Sensitive Optical Nanosensors Containing Voltage Sensitive Dyes

“…[18,19] Nanospheres composed of F127 and DOS are newly introduced research tools that have not yet been applied in intracellular analysis.…”

Drug-Protein Interactions for Clinical Research by Nucleic Acid Programmable Protein Arrays-Quartz Crystal Microbalance with Dissipation Factor Monitoring Nanoconductometric Assay

“…Moreover, there are few biosensors developed for GBM, usually for cellular sensing (Beljebbar et al, 2010;Brasuel et al, 2001;Chen et al, 2008;Desai et al, 2006;Manning et al, 1998;Trevin et al, 1998;Valero et al, 2010;Zakir Hossain et al, 2007). The objective of the present research regards the analysis of protein-drug and multiple protein-drug interaction towards potentially useful clinical applications, namely in the field of cancer studies.…”

Micro-miniature Autonomous Optical Sensor Array for Monitoring Ions and Metabolites 1: Design, Fabrication, and Data Analysis

“…16 More recently, spherical optical nanosensors or PEBBLEs (probes encapsulated by biologically localized embedding) with 20 -200 nm in diameter have been introduced by Kopelman for intracellular measurements of pH, calcium, potassium, chloride and glucose. [23][24][25][26] In this case, a fluorescent indicator was incorporated into the pores of a hydrophilic polymer matrix for pH and glucose sensing. 23,24 The same group has also explored the development of nanosensors based on PVC particles containing a lipophilic fluorescence indicator for intracellular electrolyte monitoring.…”

“…[23][24][25][26] In this case, a fluorescent indicator was incorporated into the pores of a hydrophilic polymer matrix for pH and glucose sensing. 23,24 The same group has also explored the development of nanosensors based on PVC particles containing a lipophilic fluorescence indicator for intracellular electrolyte monitoring. 25,26 Coté et al reported hydrogel microspheres incorporating a fluorescence labeled protein for glucose monitoring, which they proposed as implantable transdermal glucose biosensors.…”