Useful Chemistry And Sample/Tip Preparations; Cleaning Cantilevers And Tips - JPK instruments nanowizard afm Handbook

9. Useful chemistry and sample/tip preparations

9.1 Cleaning cantilevers and tips

There are various cases where cantilever tips should be cleaned, most fall into two
main categories. Either the surface is being prepared for some chemical
functionalization, or some material should be removed from the tip to improve
resolution. Aggressive cleaning is recommended before cantilever chemical
modification or functionalization, otherwise the results can be very variable. The
chemical activity of the surface will be quite sensitive to adsorbed hydrocarbons, for
instance, and to the degree of surface charge or oxidation. Methods such as
plasma cleaning can give a reproducible, chemically active surface so that reliable
protocols can be developed.
Even "new" cantilevers sometimes need cleaning for good imaging, especially for
high resolution imaging, since for example material from the gel packs can stick
onto the tips. It is more commonly a problem, however, after imaging, that some
contamination has stuck on the end of the tip and the imaging quality is reduced.
Sometimes it is possible to remove the material, especially from imaging soft
biological samples in liquid, where the tip is quickly contaminated but relatively easy
to clean with detergent, for example.
UV irradiation
Irradiation of the tip with a UV lamp produces ozone and "burns" organic material
from the tip.
Plasma cleaning
A 30 second treatment in an 80 W argon plasma cleaner removes organic material.
The method is recommended to use prior to tip functionalization.
Piranha solution
Prepare a mixture of 30 % H
cantilever for 30 minutes and rinse afterwards with ultrapure water. This method is
also recommended to remove the packaging material that sometimes adsorbs from
the gelpacks the cantilevers are stored in.
Nie method
Heng-Yong Nie at the University of Western Ontario, Canada, has published a tip-
cleaning method using a special kind of polymer (biaxially oriented polypropylene
film, BOPP). The basic idea is to use a soft surface to rub off contamination from
the tip.
http://publish.uwo.ca/~hnie/spmman.html
http://publish.uwo.ca/~hnie/pdf/rsi02.pdf
0 (30 %) and 70 % H SO
2 2 2
JPK Instruments NanoWizard
(conc.) (v/v). Immerse the
4
®
Handbook
Strong cleaning.
Good for chemical modification.
Strong cleaning.
Good for chemical modification.
Very strong cleaning, please note
safety considerations!
May be too aggressive for some
Mild cleaning
H.-Y. Nie, M. J. Walzak and N. S.
McIntyre. "Use of biaxially oriented
polypropylene film for evaluating and
cleaning contaminated atomic force
microscopy probe tips: An
application to blind tip reconstruction
Rev. Sci. Instr. 73 (2002) 3831-3836
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