The accumulation of metal ions in organisms and the presence of heavy metals in water cause adverse effects on ecosystems and results in numerous human health issues such as cancer and neurogenerative diseases. Therefore, the development of novel platforms for metal‐scavenging and rapid metal detection for in situ applications are of high importance. Here, this challenge is tackled by taking advantage of the metal chelation ability of a melanin‐inspired material in combination with the near‐infrared (NIR) fluorescence response of single‐walled carbon nanotubes (SWCNTs) to surface binding. SWCNTs are functionalized by a melanin‐like substance, obtained by enzymatic oxidative polymerization of a fluorenylmethyloxycarbonyl‐tyrosine (FmocY) precursor. The resulting multicomponent system (SWCNT‐FmocYOx) serves as a metal‐ion scavenging platform that concurrently reports on metal binding with optical signal transduction. Upon binding of a library of mostly divalent transition metal‐ions, the fluorescence emission of the functionalized SWCNTs is modulated, showing a concentration‐dependent response with a limit of detection in the nanomolar range. Metal‐binding and removal from water of up to 98% is further shown via inductively coupled plasma mass spectrometry. The SWCNT‐FmocYOx hybrid system presents a novel platform with NIR optical signal for real‐time feedback on metal‐ion scavenging.

Single‐Walled Carbon Nanotubes In article number 2209688, Gili Bisker, Ayala Lampel and co‐workers depict a functional, metal‐binding hybrid composed of melanin‐inspired material formed by enzymatic oxidative polymerization of Fmoc‐tyrosine as surface coverage of single‐walled carbon nanotubes (SWCNTs). The SWCNT/melanin‐like composite can scavenge and filter metal‐ions from solutions, where metal binding to the melanin‐like coating is transduced into an optical signal of the SWCNT near‐infrared fluorescence.