The analysis of bile pigments in human biofluids is essential for the discovery of new disease mechanisms. HUG is a recombinant biopolymer combining a human elastin domain (HELP) with the bilirubin-binding, fluorescent UnaG protein. It exhibits thermal responsiveness and high-affinity bilirubin detection, enabling efficient purification and nanoscale quantification of bilirubin, conjugated bilirubin, and biliverdin. Its application spans pre-clinical research, clinical and veterinary diagnostics. HUG supports biomarker development for diseases such as diabetes, cancer, and neurological disorders, aligning it with precision medicine goals. The HUG assay has been validated on paediatric and cerebrospinal fluid samples and provides new perspectives in early diagnosis and treatment follow-up. The quantification of bilirubin and biliverdin in cell cultures enables the monitoring of oxidative stress and ferroptosis, which is useful for the investigation of disease mechanisms and drug screening.
