User:Allison K. Alix/Notebook/Thesis Research/2013/07/19

Synthesis of AuNP

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AuNP synthesis procedures We will perform three procedures and observe which produces the desired AuNP diameter (~10nm) Procedure 1 Taken from User:Allison K. Alix/Notebook/Thesis Research/2013/05/10 1) Stir and heat to boiling 20mL of 1mM HAuCl4 2) Add 2mL 1% sodium citrate 3) Observe a purple to red color change 4) Determine size and concentration of AuNP using UV-Vis Procedure 2[1] 1) Boil 50mL MilliQ water in a clean beaker 2) Add 0.5 mL of HAuCl4 solution (1% w/v) 1% w/v = (0.01g in 1mL water) 3) Follow with 1.75 mL of sodium citrate solution (1% w/v) 4) Boil for about 10 minutes until solution color changes to bright red 5) Replace water lost to evaporation during boiling 6) If a higher concentration is desired, centrifuge at 14 000 rpm and resuspended in MilliQ water Procedure 3[2] 1) Bring 100 mL of solution containing 0.01 g of HAuCl4·3H2O to reflux 2) Add 3 mL of 1% sodium citrate solution while stirring 3) Boil solution for another 40 minutes 4) Cool to room temperature Obtain UV-Vis Spectra of all AuNP Fluorescent changes based on number of G-quadruplexs formed We have already seen that increasing the DNA concentration of an 8-repeat strand results in an increased fluorescence signal. But what happens when we keep concentration of DNA constant and instead decrease the number of repeats to 4, so that only 1 G-quadruplex is formed? Although it was seen that this trend was true using ZnPPIX as a G-quadruplex inducer and fluorescent sensor, it would be beneficial for this research to examine if the same was true for ThT. This would support the idea that the number of G-quadruplexes can be determined based on fluorescent measurements, both bulk and FCS.