The last couple of posts showed that homemade HBSS does not cause discoloration, even though commercial HBSS does. I wanted to test if there was something mysteriously special about this solution, so I looked at non-RTP’ed wafer 622 in the incubator in solutions with and without serum (10% FBS). Even without serum, the cell media…
Demos of the Molecular Devices M2e and Tecan Infinite M200 are done. Erik from Tecan left us the M200 to use until October 6th. Please come try out your assays on it. Or check sensitivities. Jess or I could probably steer you in the right direction as far as the software is concerned. My impressions…
I decided to find another supplier for HBSS and found one: CellGro. CellGro HBSS had the same components as Gibco HBSS, although a couple of the concentrations were different. I tested out this new HBSS vs. homemade HBSS. Here, the commercial versions of HBSS caused discoloration within a day, but my homemade HBSS didn’t. The…
Last week, we wondered whether the wells of pncSi chips created an unstirred volume in which an extreme environment could form (pH, byproducts), thus accelerating discoloration. To investigate this, I placed one chip flat on the bottom of a plate and another chip balanced upright on the sidewall of a well. I rotated the plate…
In these discoloration tests, I looked at the components of HBSS. HBSS consists of NaCl, KCl, 0.048 mg/mL Na2HPO4, 0.06 mg/mL KH2PO4, glucose and 0.35 mg/mL NaHCO3. In a previous post, I showed that NaCl, KCl and glucose didn’t cause discoloration (previous post). So, I made HBSS from scratch and I combined the various phosphate…
For this experiment, I looked into the stability of RTP treatment. Specifically, I tested discoloration rates for chips at different time points after I did RTP. The idea was to see if the beneficial effects of RTP depended on the time that chips were stored after RTP processing. Here’s the data: All chips were from…
Last week, JP deposited 25nm SiO2 for me on wafer 644 (which I cleaned in the UV/Ozone before I gave it to him). Unfortunately, someone broke the E-Beam that day and JP was only able to deposit on 1 side of the wafer (the solid side). I did some experiments on the wafer anyway. First,…
I talked about this yesterday in lab meeting, but here is the data. Since the components of HBSS by themselves did not cause discoloration (HBSS components), I adjusted the concentrations of NaCl, KCl, glucose, Na2HPO4 and NaHCO3 to match that of DMEM. The control was a wafer in DMEM/F12 with 10% FBS. None of these…
This week, I did a quick discoloration experiment based on Chris’s comment at lab meeting. He wondered if soaking the chips in water for a while would allow potential discoloration-causing contaminants to slowly leech out. I took 2 chips from wafer 622 and soaked them in ~ 300mL DIH20 overnight (with a couple of water…
In my last discoloration experiment, I tested buffers with different pKa’s (MES, HEPES, and Tris). I found that only 10 mM HEPES in HBSS caused discoloration, and furthermore, that the HBSS component of this solution was the culprit (post). Fortunately, HBSS is a rather simple solution; it only consists of KCl, NaCl, Glucose, KH2PO4, Na2HPO4…
