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From 2013.igem.org

05-08 - 11-08-13

Melting Gold Nanoparticles to Solid Gold

Step 1: Cultivation of D. acidovorans
200 ml ACM medium were inocculated with recently obtained D. acidovorans SPH-1 from glycerol stock and incubated at 30°C for 3 days.

Step 2: Precipitation of Gold Nanoparticles

• D. acidovorans culture in ACM was divided in 50 ml aliquots and centrifuges at 3,750 rpm for 30 min.
• Supernatant was transferred to fresh tube.
• 300 µl gold chloride stock solution [µg/ml] was added to D. acidovorans supernatant, suspention mixed and incubated at RT for 20 min.

Fig.2.1 Supernatant of D. acidovorans.

Fig.2.2 Precipitated gold nanoparticles in D. acidovorans supernatant.

Step 3: Aggregation of gold nanoparticles.

Fig.3 Gold nanoparticle solution on melting pot.

Step 4: Melting gold nanoparticles to solid gold.

Fig.4.1 Heating aggregated gold nanoparticles in melting pot.	Fig.4.2 Heating aggregated gold nanoparticles in melting pot upside down.	Fig.4.3 Remaining solid gold in melting pot.	Fig.4.3 Sparkling gold appearing in the melting pot.
Fig.4.4 Final recovered solid gold collected in tube.

Alternatively, we also performed the protocol described above in a 2 ml tube.

Fig.5 Solid gold recovered from nanoparticles in 2 ml tube.