SpecMat request: Protein solutions of PBS and BSA
mtang at stanford.edu
Tue Jun 29 08:49:10 PDT 2010
Hi Meredith --
OK, the RI analysis makes sense, although you should check with Ed about
the model -- there will likely be a concentration gradient in your
samples. Your sample handling procedure is fine for the SEO contact
analyzer, but you'll have to check with Ed for the Woollam.
I think EH&S could pick up biohazardous waste from SNF, but they won't
be expecting it. I suggest checking with the Kovacs lab group to see
what they do and maybe borrow the appropriate labels and bags. I'm not
sure small amounts of BSA needs to be handled specially, but it's best
to be conservative and show your REU's good lab practices.
Let me know what the Kovacs lab people say and I'll also drop a note to
Meredith M. Lee wrote:
> Hi Mary,
> Thanks for the quick reply -- yes, we agree we don't want the
> solutions touching anything that is not ours and disposable.
> For the Woollam, we planned to dispense the solution wet, take a
> measurement set, then dry and take another measurement set.
> We want to know the refractive index of BSA at different
> concentrations if the BSA is wet or dry. This is because in our
> "real" samples with photonic crystals we can detect binding events in
> two ways - (1) while the solution is covering the surface, or (2)
> after drying out the microchannel -- i.e. BSA in air (with greater
> index contrast).
> Do you prefer for us to dispose of the waste outside of SNF?
> Meredith M. Lee
> Stanford University
> Ph.D. Candidate, Dept. of Electrical Engineering
> Center for Integrated Systems
> 420 Via Ortega, Stanford, CA 94305-4075
> Fax: (650) 723-4659
> mmlee at stanford.edu <mailto:mmlee at stanford.edu>
> On Mon, Jun 28, 2010 at 7:43 PM, Mary Tang <mtang at stanford.edu
> <mailto:mtang at stanford.edu>> wrote:
> Hi Meredith -
> No, your first SpecMat message did not get through - the list is
> As for the contact angle measurement tool, your solutions and
> procedure sound fine. I think the main concern for either the SEO
> contact angle or the Woollam is guarding the solutions touching
> any other surface since PBS contains sodium. I wasn't sure from
> the description -- is the measurement on the woollam done on wet
> or dried film? (I'm just not sure of the value of information
> about a wet drop...)
> Meredith M. Lee wrote:
>> Hi, not sure if this email went through--forwarding below!
>> ---------- Forwarded message ----------
>> From: *Meredith M. Lee* <mmlee at stanford.edu
>> <mailto:mmlee at stanford.edu>>
>> Date: Mon, Jun 28, 2010 at 6:58 PM
>> Subject: SpecMat request: Protein solutions of PBS and BSA
>> To: specmat at snf.stanford.edu <mailto:specmat at snf.stanford.edu>
>> Cc: Philip Ponce de Leon <philponce325 at gmail.com
>> <mailto:philponce325 at gmail.com>>, elkallas <elkallas at stanford.edu
>> <mailto:elkallas at stanford.edu>>, James Harris
>> <harris at snow.stanford.edu <mailto:harris at snow.stanford.edu>>
>> As part of an NNIN REU project (student Phil Ponce de Leon,
>> "Surface Treatments for Controlling Hydrophobicity of Photonic
>> Crystal Biosensors"), we are interested in measuring the contact
>> angle and refractive index of solutions of BSA (bovine serum
>> albumin) suspended in PBS (phosphate buffered saline). PBS and
>> BSA are obtainable at the campus Biostores and are kept chilled
>> in a refrigerator at 4 deg C in BioX after the different
>> concentration solutions have been made (in BioX). The amount of
>> solutions we would like to bring into SNF, and suggested
>> operating procedures are listed below.
>> The two pieces of equipment we would like to use are:
>> *Contact Angle Tool*
>> Using our own syringe and syringe tips for handling the BSA/PBS,
>> we would like to dispense drops (20 microliters) on our wafers.
>> Suggestion for disposal after measurement is to absorb droplets
>> with a cleanroom wipe and put in a ziploc bag in biohazard waste,
>> and to take out of SNF for disposal in BioX. The wafer surfaces
>> would be Si, or SiNx, either bare or with teflon or silanized,
>> and can be disposed of after the test, or kept in containers
>> clearly marked for later repeated test to determine the longevity
>> of surface treatments. Standard practice of labels for
>> "chemicals/solutions in use" would be followed, and any
>> accidental spillage will be handled from procedures used in BioX
>> or Genome Technology Center labs. (or if specmat can suggest
>> desired procedures).
>> *Woollam Ellipsometer*
>> We would like to use our own pipette and pipette tips (disposed
>> of in our own sharps wastebin) to dispense (again 10s of
>> microliters) solutions onto "wells" that are defined by O-rings
>> taped down with kapton tape on 4" Si wafers. The solution
>> dispensing would be done immediately before an ellipsometry
>> measurement on the Woollam. Dessicant will be used to dry the
>> wells, and a "dried protein solution" measurement will be taken
>> before removing the sample.
>> */The nature of the project is such that after contact with the
>> BSA/PBS solutions, the samples will not go into any other
>> equipment. /*
>> The mentors for this REU project are post doc Pascale El Kallassi
>> and PhD student Meredith Lee, under Prof. Jim Harris. Each
>> person handling the above experiment will have taken the
>> bio-safety course on STARS Stanford training.
>> Please let us know if this proposal would be acceptable. Thanks!
>> Meredith M. Lee
>> Stanford University
>> Ph.D. Candidate, Dept. of Electrical Engineering
>> Center for Integrated Systems
>> 420 Via Ortega, Stanford, CA 94305-4075
>> Fax: (650) 723-4659
>> mmlee at stanford.edu <mailto:mmlee at stanford.edu>
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