MiSeq and NextSeq Glass Compared.

Yesterday I posted some notes on the NextSeq 550 flowcell and noted my confusion about the glass used in the NextSeq 550. Today I decided to try and make some more measurements in the spectrophotometer… the results are as follows:

I decided to cut a small aperture in some black tape and use this as the baseline for comparison. This meant I could then cover up the flowcell regions outside of the channel itself so I wouldn’t get any contribution from the black material on the NextSeq 550 flowcell or the bonding material used on the Miseq flowcell. The original images are shown below. The figure above roughly aligns everything for comparison.

Based on these measurements the MiSeq flowcell still looks like regular borosilicate slide glass to me. The NovaSeq is transparent much further into the UV range suggesting to me it’s closer to (or is) fused silica. But weirdly the NextSeq 550 glass is somewhere in between.

So… I still don’t know what this is! But at least we have some slightly better data…

In part this has cost implications (borosilicate is cheaper than fused silica). But I’m also just curious to know how flowcell development has progressed…