International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2015): 78.96 | Impact Factor (2015): 6.391 Volume 6 Issue 2, February 2017 www.ijsr.net Licensed Under Creative Commons Attribution CC BY Z-scan Technique for Measurements of Glucose Concentrations through the Formation of Plasmonic Gold Nanoparticles Prepared by Green Synthesis F. Abdulwahab 1 , F. Z. Henari 2 1, 2 Department of Medical Sciences, Royal College of Surgeons in Ireland, Medical University of Bahrain, Building 2441, Road 2835, Block 228, Busaiteen, Kingdom of Bahrain Abstract: Gold nanoparticles were synthesized by microwave irradiation using glucose as a reducing and stabilizing agent. The effects of using different concentrations of glucose in the synthesis of nanoparticles were investigated. The formation of gold nanoparticles was confirmed using UV-Vis absorption spectra and Transmission Electron Microscope(TEM). Z-scan technique was used to measure the nonlinear refraction indices of the gold nanoparticlessynthesized with different glucose concentrations. A linear relationship was found between the nonlinear refractive index of the total gold-glucose and concentration. Thus the calculated values of the nonlinear refractive index may be used for measuring an unknown glucose concentration in a sample. Keywords: gold nanoparticles, green synthesis, microwave, absorption spectra, nonlinear properties, Z-scan 1. Introduction In recent years, there has been huge interest in research on metal nanoparticles due to their potential applications in the field photonics, optoelectronics such as sensors (1), and in medical applications such as diagnosis, drug delivery and cancer treatments (2–5).Recently, research has focused on green synthesis nanoparticles using plants and carbohydrate as a reduction agent and stabilizer (6,7). In the preparation of Au nanoparticles,glucose has been considered as one kind of reducing and capping agent(8),which plays an important role in preventing agglomeration and in controlling the formation of nanoparticles and their stability. Chemical methods are also used to synthesize gold nanoparticles(9). The synthesis of gold nanoparticles using microwaveheating has been reported (10). Metal nanoparticles have a surface plasmon resonance (SPR) absorption in the visible region, which arises from collection motion of free electrons in the conduction band. The presence of SPR band enhances the nonlinear optical properties. These properties have a crucial role in development of optical limiting devices and optical switches. Applications with these nanoparticles can be used in detection of glucose level in blood(11). Glucose is the main energy source for the human body. The concentration of blood glucose is regulated by several hormones, such as insulin and glucagon. The quantification of glucose in the blood is used for diagnosing metabolic disorders of carbohydrates, such as diabetes. Currently, the methodology used for this determination is the enzymatic colorimetric with spectrophotometric reading. Among other optical diagnostic methods, a nonlinear optical method is used for determining the changes in glucose level not detected by conventional methods. Determining glucose level using the nonlinear refractive index has been reported(12,13), where it has found a linear relationship between the measured nonlinear refractive index values and glucose concentration. One such method for measuring refractive index is the z-scan technique. In this study, gold (Au) nanoparticleswere synthesized using glucose as a reduction agent and stabilizer under microwave heating. The nonlinear optical properties of Au nanoparticles combined with glucose were measured using the z-scan technique(14). Samples with different glucose concentrations were prepared. The formation of nanoparticles was monitored by measuring the UV-Vis absorption spectra. The maximum absorption band (SPR) was centered at 526 nm. The size distributions of synthesized nanoparticles were identified using Transmission Electron Microscopy (TEM).The z-scan experiment was performed using a 488 nm CW Argon-ion laser with a power of 29.2 mW. Effects of glucose concentration with embedded Au nanoparticles on the nonlinear refractive index were measured. The measurements showed a linear relationship between the glucose concentration and the nonlinear refractive index (  2 ). 2. Experimental 2.1 Materials and methods Gold chloride (HAuCl 4 ) , sodium hydroxide (NaOH) and glucose ( C 6 H 12 O 6 ) were purchased from Sigma Aldrich. Distilled water was used throughout the experiment, even for washing glassware. 2.2 Synthesis of gold nanoparticles For the green synthesis of gold nanoparticles, in a test tube 68.4 μL of 1% wt. gelatin, 22.8 μL of 1 M NaOH, 454.6 μL of different concentrations of glucose and 454.6 μL of 10 mM HAuCl 4 were added, respectively. Then the test tube was heated in a microwave oven at low power for 30 seconds and was allowed to cool to room temperature for further analysis. Formation of gold nanoparticles was confirmed by the color change from colorless to red. In this reaction, glucose reduces gold chloride (Au +3 ) to gold atoms Paper ID: ART20164701 DOI: 10.21275/ART20164701 23 refractive index may be used for measuring unknown glucose concentration in a sample. gold nanoparticles, green synthesis, microwave, absorption spectra, nonlinear properties, Z-scan In recent years, there has been huge interest in research on metal nanoparticles due to their potential applications in the field photonics, optoelectronics such as sensors (1), and in medical applications such as diagnosis, drug delivery and research has focused on green synthesis nanoparticles using plants and carbohydrate In the preparation of In the preparation of nanoparticles,glucose has been considered as one kind of reducing and capping agent(8),which plays an important role in preventing agglomeration and in controlling the formation of nanoparticles and their stability. Chemical methods are also used to synthesize gold nanoparticles(9). The synthesis of gold nanoparticles using microwaveheating has been Metal nanoparticles have a surface plasmon resonance (SPR) absorption in the visible region, which arises from collection motion of free electrons in the conduction band. The presence of SPR band enhances the nonlinear optical properties. These properties have a crucial role in development of optical limiting devices and optical In this study, gold (Au) nanoparticleswere synthesized using glucose as a reduction agent and stabilizer under microwave heating The nonlinear optical properties of Au nanoparticles combined with glucose were measured using the z-scan Samples with different glucose concentrations were prepared. The formation of nanoparticles was monitored by measuring the UV-Vis absorption spectra. The maximum absorption band (SPR) was centered at 526 nm. The size distributions of synthesized nanoparticles were identified using Transmission Electron Microscopy (TEM).The z-scan experiment was performed using laser with power of 29.2 mW. Effects of glucos concentration with embedded Au nanoparticles on the nonlinear refractive index were measured. The measurements showed a linear relationship between the glucose concentration and the nonlinear refractive index ). 2.1 Materials and methods