This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-Non Commercial- ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms. © 2018 Journal of Advanced Pharmacy Education & Research | Published by SPER Publication 5 A Highly Sensitive and Selective Photometric Creatinine Assay Using Padina pavonica Silver Nano-Probe Ahmed H. A. Hassanein 1* , Raghda R. S. Hussein 2 , Ahmed Ali Farghali 3 , Ibraheem B.M. Ibraheem 4 1 Biotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences (PSAS), Beni-Suef University, Beni-Suef, Egypt, 2 Clinical Pharmacy Department, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, Egypt, 3 Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences (PSAS), Beni-Suef University, Beni-Suef, Egypt, 4 Botany and Microbiology Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62514, Egypt. Correspondence: Ahmed H. A. Hassanein, Biotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences (PSAS), Beni-Suef University, Beni-Suef, Egypt. E_mail: alsherif.a@gmail.com ABSTRACT Creatinine (Crn) is the most frequently ordered renal analyte in medical labs. The most commonly used technique for the detection of Crn is Jaffe’s reaction, a well-known analysis used on routine basis for biological samples. However, during the estimation of Crn in biological fluids, other components like urea, uric acid or some minerals change the results to be higher than it should. To overcome such lack of accuracy, this study developed a silver nano-probe for the detection of Crn selectively and precisely. This is a novel approach based on the traditional Jaffe’s reaction with the advantage of high sensitivity and selectivity to detect Crn. The AgNPs based probe proficiently and selectively recognizes Crn by forming a complex with the Crn even in the presence of other interfering constituents. This complex formation leads to a color change that can be detected visually and spectrophotometrically. A correlation was found to be linear starting from 0.01 μM to 1 μM concentrations of Crn in solution with an R 2 value of 0.998 and a detection limit of 12 nM. To validate the reliability of the present method, the probe tested to assay Crn in human urine samples to insure the sensitivity and selectivity. Afterwards, the results were compared to the results of the Jaffe’s analysis. The developed approach found to be highly sensitive and selective and can be used as a routine method for the analysis of Crn. Keywords: Creatinine, padina pavonica, silver nanoparticles, jaffe’s reaction, bare nanoparticles, biosynthesis, nano-probe. Introduction Crn (C 4 H 7 N 3 O) is a well-known biomarker that is used widely in clinical analysis. Crn is produced from creatine phosphate metabolism in the muscles of the human body as a waste product, going through the blood stream and eliminated by the kidneys periodically. The serum Crn concentration levels indicate how the kidneys are functioning and they give indications also about the muscular and thyroid functions. Moreover, Crn levels in urine could be used as an indicator of urine dilution in a method used usually by the anti-doping syndicates in the analytical tests for different sports. The levels of Crn in the blood which are considered within normal limits are 40–150 mM, while the Crn concentrations are lower by a significant difference in children or patients with decreased muscle mass [1] . The Crn analysis methods in blood and urine are varied widely. The photometric methods and the enzymatic colorimetric methods are used widely for the analysis of Crn [2, 3] . These methods are fast, easy and cost-effective but with the presence of many metabolites and other chemicals or drugs in the urine specimen such as urea (CO(NH 2 ) 2 ), uric acid (C 5 H 4 N 4 O 3 ), ascorbic acid and some antibiotics like (cephalosporins), the results may become falsely elevated. Jaffe-based methods inculpate serum or urine sample mixing with alkaline picrate and the resulted absorbance change detected by UV [4] . Being simple, they can be automated and highly affordable, Jaffe-based methods have continued to be used on large scale into the 21 st century, despite of their lack of the selectivity. Enzymatic, capillary electrophoresis (CE) [5] , Liquid chromatography [6] and ion-exchange methods provided high sensitivity and selectivity but have other drawbacks of being complicated and expensive [7] . In addition, high-performance liquid chromatography (HPLC), is highly specific and sensitive, and has been considered as the new reference method Access this article online Website: www.japer.in E-ISSN: 2249-3379 How to cite this article: Ahmed H. A. Hassanein, Raghda R. S. Hussein, Ahmed Ali Farghali, Ibraheem B.M. Ibraheem. A Highly Sensitive and Selective Photometric Creatinine Assay Using Padina pavonica Silver Nano-Probe. J Adv Pharm Edu Res 2018;8(2):5-11. Source of Support: Nil, Conflict of Interest: None declared.