Naked eye detection of infertility using fructose blue--a novel gold nanoparticle based fructose sensor

A simple and low cost colorimetric method, requiring no instrumentation, is presented for the detection of fructose in human semen, a marker of seminal vesicle function. In this study we have synthesized a novel gold nanoparticle (AuNP) based sensor, named as fructose blue, by co-functionalizing AuNPs with 3-aminophenyl boronic acid (APB) and L-glutamic acid-(2,2,2)-trichloroethyl ester (GTE). The red-shift in the plasmon absorption spectra of fructose blue with different fructose concentrations accompanied by colour change of the solution from red to blue is the principle applied here for the estimation of fructose. The novel co-functionalized nanoparticles (NPs) have better colour change response for fructose than that of the earlier reported fructose sensors based on AuNPs functionalized by the APB moiety alone. The proposed method showed linearity in the range of 0.5-6 mg/mL with a detection limit of 0.3 mg/mL, and exhibits excellent selectivity for fructose over a collection of sugars. The method was successfully applied for detection of fructose in real samples of semen and agrees well with values obtained from conventional methods. The method depicted here for the detection of semen fructose is indeed superior to the existing methods in the sense that it can be performed at home as a preliminary self-screening test by patients suspecting infertility for warranting further medical attention and provides privacy also. Moreover the method is important, particularly in third world countries where high-tech diagnostic aids are inaccessible to the bulk of the population.