A　bioinspired　fluorometric　method　has　been　developed　for　the　detection　of　glutathione　(GSH)　in　biological　fluids.　It　is　based　on　the　use　of　near-infrared　fluorescent　semiconducting　polymer　dots　(P-dots)　and　of　the　dopamine　(DA)-melanin　nanosystem.　The　P-dots　were　prepared　from　poly(styrene-co-maleic　anhydride),　the　semiconducting　polymer　poly[(9,9′-dioctyl-2,7-divinylenefluorenylene)-alt-2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene]　and　the　fluorescent　dye　tetraphenylporphyrin.　They　have　excitation/emission　maxima　at　458/656 nm,　and　this　enables　measurement　to　be　performed　with　low　autofluorescence　and　scattering　background.　DA　can　self-polymerize　on　the　surface　of　the　P-dots　to　yield　a　poly-DA　coating.　This　coating,　at　weak　alkaline　pH　values,　causes　the　quenching　of　the　fluorescence　of　the　P-dots.　However,　the　polymerization　of　DA　is　inhibited　by　GSH.　Hence,　quenching　of　fluorescence　is　prevented.　This　effect　was　used　to　design　a　fluorometric　assay　for　GSH　that　has　good　selectivity　and　sensitivity.　Under　optimal　conditions,　the　method　has　a　linear　response　in　the　0.2　to　20 μM　GSH　concentration　range　and　a　60 nM　detection　limit.　It　was　successfully　applied　to　the　determination　of　GSH　in　HepG2　cells　and　in　spiked　human　serum.　[Figure　not　available:　see　fulltext.].　©　2019,　Springer-Verlag　GmbH　Austria,　part　of　Springer　Nature.