There have been differences between the previous long term discoloration studies carried out by myself and Barrett. Couple of reasons speculated for the differences were: 1) Wafer variation (w683 vs w704); w683: has no visible pores, is more amorphous in character, and has many pinholes; w704: 200um series. 2) Silanization treatment (UVO chamber PDMS contamination;…
This experiment was carried out to determine the maximum life of pnc-Si in cell culture conditions based on discoloration. All the discoloration slowing factors were put together to see how long would the membranes last for. These include: samples in 3D format (Sepcon) with ‘membrane side’ down (with no intact membranes), all in incubator, DMEM…
I repeated Barrett’s discoloration array experiment (Array1, Array2). NaCl solution was prepared @ concentrations: 0, 0.25 (0.1), 0.5 and 1M, whereas NaHCO3 solution was prepared @ 0, 0.475, 0.95, 1.90 (and 3.80) mg/ml. Different combinations of both these salt solutions were used and discoloration of non treated samples in oven@ 37C was monitored over different…
As seen before, in 2D format ‘RTP+silanization’ helps. Similarly in 3D format, with membrane side down, the same treatment helps prevent discoloration till 5 days. (samples from W413) Above figure shows how combined effect of RTP and silanization is better than just RTP/Silanization or none. (the weird discoloration pattern could be a result of few…
In continuation of the previous post, I ran the pore processing software for two samples (t=0 and t=150 min). The following histograms show the pore parameters and the difference in the pore size and numbers between the two samples. I am not sure if the difference between the pore sizes could be due to sample-sample…
There has been uncertainty with process of dissolution of pnc-Si in cell growth media. Whether the media enters the pores and ‘eats away’ the material leading to increase in pore sizes and eventually complete degradation was the question. Thinning of the material would have taken place too. To have a clear picture about this, I…
After recent studies with surface treatments, we wanted to take a step further by trying amino silanization on RTP’ed samples. Wafer 413 samples were RTP’d with no intact slits. Both 2D and 3D formats were tested in DMEM (-FBS) in oven @37C. All 3D samples had membrane side facing down whereas, in 2D format the…
A bunch of samples from W683 (no RTP) were liquid silanized and used in 3D format to track discoloration in comparison to control sample, in DMEM(-FBS) @ 37C in Oven. I used all the cracked chips which broke while clamping them into Sepcons. Instead of tossing them off, I just wanted to repeat the discoloration…
Surface treatments like silanization were seen to slow down discoloration in the past. I carried out liquid amino-silanization (protocol in place) of samples from W683 (no RTP) and used them in both 2D and 3D format to monitor discoloration in DMEM(-FBS) @ 37C in Oven. Also BSA coated samples were used side by side for…
I carried out a repetition of BSA coating experiment with both 2D and 3D formats. With 2D, I get the same result as before, but surprisingly, in Sepcon 3D format we observe the opposite to what we see in 2D! (can be seen in the figure below) All the three samples with different BSA coatings…