A versatile platform for designing optical nanosensors is
proposed. The “sensing chemistries” are entrapped into
the poly(styrene-block-vinylpyrrolidone) nanobeads having
the average size of 245 nm in aqueous media.
Addressable staining into the core or the shell of the beads
results in nanosensors for essential analytes such as
dissolved oxygen, temperature, pH, chloride, and copper
ions. Two immobilization procedures are developed:
staining in the polystyrene core is performed from a
tetrahydrofuran/water mixture (50:50 v/v) and staining
in the poly(vinylpyrrolidone) shell is achieved by using
the ethanol/water mixture (70:30 v/v). The oxygen and
temperature indicators should be preferably immobilized
into the core, whereas nanosensors for ions are manufactured
by staining into the shell. In the case of the
lipophilic pH indicators both procedures result in similar
pKa values. The unique properties of the beads make them
promising for sensing and imaging even in very complex
media, multianalyte sensing, and monitoring of very fast
processes.
four times every 3 days until it was colorless.rized