Red emissive carbon dots-based probe for rapid identification and continuous tracking of Gram-positive bacteria in tumor cells

[Display omitted] •Red and blue emissive carbon dots were synthesized to construct fluorescent probes.•The probes can rapid discriminate and track Gram-positive bacteria for a long time.•The probes can detect Gram-positive bacteria in the microenvironment of cancer cells.•The probes can identify the growth and division state of Gram-positive bacteria. Red fluorescent carbon dots (R-CDs) and blue fluorescent carbon dots (B-CDs) were synthesized, and then coupled with D-alanine (D-Ala) to construct CDs based probes (R-CDs@D-Ala, B-CDs@D-Ala). The two probes can not only rapidly and selectively identify Gram-positive bacteria within 30 s, but also keep continuous tracking for 24 h. Further, R-CDs@D-Ala was successfully used to detect G+ bacteria from Hela cells, showing good identification results. Moreover, the fluorescence superposition of the two probes can display the differences in the growth and division status of different G+ bacteria, providing strong support for bacterial diagnosis and treatment in the tumor microenvironment. Therefore, CDs based nanoprobes provide a rapid and effective method for diagnosis of bacterial infectious diseases and has good practical application value.