Method for increasing sensor resolution by spectrally stacking responsive dyes

A method for forming an analyte-sensitive substance, the method comprising:

• forming a first solution comprising:
• (i) an organic solvent, (ii) an ionophore, wherein the ionophore comprises a hydrophobic substance, wherein the ionophore is configured to provide a local pH within the analyte-sensitive substance related to a concentration of an analyte proximate the analyte-sensitive substance, and (iii) a pH-sensitive fluorophore, wherein the pH-sensitive fluorophore comprises a hydrophobic substance, wherein the pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that increases or decreases as a function of the local pH over a range of pH values according to an intrinsic intensity function, wherein the intrinsic intensity function has a first rate of change of fluorescence intensity over the range of pH values;
• combining the first solution and an aqueous solution, wherein at least one of the first solution or the aqueous solution comprises an amphiphilic compound;
• and
• evaporating the organic solvent to form a plurality of nanoparticles, wherein each nanoparticle of the plurality of nanoparticles comprises the pH-sensitive fluorophore and the ionophore enclosed within a layer of the amphiphilic compound.