Carbon quantum dots(CDs)have been widely investigated because of their tunable fluorescence properties and low toxicity.However,so far there have been no reports on in vivo functional studies of hair and skin derived CDs.Here,hair derived CDs(HCDs)and skin derived CDs(SCDs)were obtained by using human hair and pig skin as precursors.The quantum yield(QY)of HCDs and SCDs were 86.06%and 51.35%,which were quite high,compared to citric acid derived CDs(CCDs).These HCDs and SCDs exhibited multicolorful fluorescence and excitation-dependent behavior.Although HCDs and SCDs have almost similar chemical properties like CCDs,the affinity and fluorescent property are dramatically different.In vivo comparative studies demonstrated that HCDs and SCDs possess optimal photostability,hypotoxicity and biocompatibility in zebrafish,which indicated that HCDs and SCDs possess the capacity of being used as fluorescence probes for in vivo biological imaging.The long-time observation for fluorescence alternation of CDs in zebrafish and the quenching assay of CDs by ATP,NADH and Fe3+ions demonstrated that the decaying process of CDs in vivo might be induced by the synergistic effect of the metabolism process and quenching of internal substances for CDs.The quenching assay of CDs further demonstrated that HCDs and SCDs can also be used as probes for detection of special substrates.All results indicated that large batches and high QYs of CDs can be acquired by employing natural and nontoxic hair and skin as precursor,because of their ubiquitous,benign,cheap and(-NH2 and-COOH)-containing properties.To our knowledge,this is the first time to report SCDs,in vivo comparative studies of HCDs,SCDs and CCDs as bioprobes,and explore their mechanism of photostability in zebrafish.