User:Madeleine Y. Bee/Notebook/Single Molecule Fluorescence/2013/07/15
AuNP/DNA Attachment, MHA Day One Procedure | <html><img src="/images/9/94/Report.png" border="0" /></html> Main project page <html><img src="/images/c/c3/Resultset_previous.png" border="0" /></html>Previous entry<html> </html>Next entry<html><img src="/images/5/5c/Resultset_next.png" border="0" /></html> |
July 15, 2013DNA and AuNP Attachment ProcedureAdapted from Instantaneous and Quantitative Functionalization of Gold Nanoparticles with Thiolated DNA Using a pH-Assisted and Surfactant-Free Route with Supporting Information containing the specific procedure used. Calculations
Extraction Procedure
Absorbance Data<br.> Corrected using HEPES buffer as a reference solution.<br.> <br.> <br.> Replicated; corrected using HEPES buffer as a reference solution. NotesPreviously, the extracted DNA and AuNP had been mixed and allowed to react for 5 minutes before adding the sodium citrate buffer. However, we think this may be affecting the aggregation of the AuNPs so in this procedure we added the buffer immediately to the AuNP and DNA solution. Additionally, we referred back to the literature and realized the final concentration of sodium citrate buffer in solution needs to be 10mM when we had previously been doing 20mM. Changing this and adding the buffer immediately allowed for the DNA/AuNP attachment, as evident in the spectra. I had some difficultly extracting the supernatants, as the nanoparticles are easily disturbed after centrifugation. Because of this, hardly any absorbance was observed for the final sample. The procedure will be replicated, and concentrations of DNA and AuNPs will be calculated using Beer's Law.<br.> The supernatants contain such a significant amount of nanoparticles because we were unsure of how long to centrifuge the samples. By trial and error, we believe the best settings are approximately 11 minutes at 10000 rpm, or until the nanoparticles are visibly at the bottom of the tube and the solution has lost most pink color, characteristic of dispersed gold nanoparticles. If 11 minutes is visibly insufficient, repeat at 10000 rpm for two minutes at a time.<br.> MHA Day One ProcedureOriginally outlined on 05/24/2013, updated on 07/12/20130<br.>
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