Selective, colorimetric assay of glucose in urine using G-quadruplex-based DNAzymes and 10-acetyl-3,7-dihydroxy phenoxazine

► A selective, colorimetric assay for detection of glucose in urine was developed. ► The color change of 10-acetyl-3,7-dihydroxy phenoxazine (ADHP) from colorless to red was used to sensing glucose. ► Oligonucleotide, which can form a stable G-quadruplex in the absence of K+, was used.