Nano optical probe samarium tetracycline complex for early diagnosis of histidinemia in new born children

A new, precise, and very selective method for increasing the impact and assessment of histidine as a biomarker for early diagnosis of histidinemia disease in new born children was developed. The method depends on the formation of the ion pair associate between histidine and the nano optical samarium tetracycline [Sm-(TC)2]+ complex doped in sol-gel matrix in a borate buffer of pH 9.2. The [Sm-(TC)2]+ complex has +I net charge which is very selective and sensitive for [histidine]- at pH 9.2 in serum and urine samples of histidinemia disease. Histidine enhances the luminescence intensity of the nano optical [Sm-(TC)2]+ complex at 645 nm after excitation at 400 nm, in borate buffer, pH 9.2. The remarkable enhancement of the luminescence intensity at 645 nm of nano [Sm-(TC)2]+ complex doped in sol-gel matrix by various concentrations of the histidine was successfully used as an optical probe for the assessment of histidine in different serum and urine samples of new born children infected by histidinemia. The calibration plot was achieved over the concentration range 1.4×10−5 - 6.5×10−10 mol L−1 histidine with a correlation coefficient of (0.998) and a detection limit of (3.2×10−10 mol L−1). The sensitivity (98.88%) and specificity (97.41%) of histidine as a biomarker were calculated.