standardization in afm for life sciences oct 18-19,...

www-dsv.cea.fr/[email protected] 1/1818-JUL-12

Standardization in AFM for Life SciencesOct 18-19, 2012

Madrid


AGENDA

As always, go to the website!

Today:•Morning scientific presentations•Morning manufacturer presentation•Afternoon round tables•Afternoon summary (eventually on Friday)

Friday:•Possible additional presentation•Preparation of project road-map


One day, we had a dream!

Ultimate goal in nanomedicine: black box with only a sample to insert!

Sample Result

The main obstacles to transfer AFM to medical applications concern both the scientific community and the AFM manufacturers.The aim of the COST Action is to identify these obstacles.One of the main obstacle is AFM standardization.


Why manufacturers are invited today

1. To inform them at the early beginning of the process

2. Get their feedback as soon as possible

3. To involve them for real mutual benefit

4. Imagine universal interface??


STANDARDIZATION

1. Merriam Webster (standardize):to compare with a standardto bring into conformity with a standard

2. Business dictionary:Formulation, publication, and implementation of guidelines, rules, and specifications for common and repeated use, aimed at achieving optimum degree of order or uniformity in a given context, discipline, or field.


Standardization aim:•Define standards (historically test objects) in three AFM domains:

•Imaging•Force•Mechanics

•Define protocol to measure these standard (independent of machine)

AFMDB aims: Publication and “data storage”•What is acceptable data (imaging, force, mechanics)?•What is resolution, what kind of averaging, which tip for mechanics,…•How to deposit raw data for future use (what format…)?

AIM of the PROJECT and OBJECTIVES of this WORKSHOP

What’s next:•Organize and structure future steps (next meeting: Enschede, U. Twente, 03/13)


What is not included:

What is not included:•“Machine” metrology: scanner, tips•Standardization of AFM interface•ISO and other international institutions


OTHER EFFORTS

Manufacturer:Various PDMS surfaces for mechanical measurement

Workshops:International Symposium on SPM Standardization (Korea, China, Japan)


Need to perform sub-groups:•Standardization•AFMDB

MechanicsForceImageMechanicsForceImage

AFMDBStandardization

Goal:Publish a COST Action paper on our advancement in Standardization on the topic:

Test objects and standardization in AFM for Life Sci ences

P.S.: We take the term “test object” from the paper Test objects and other epistemic things: a history of a nanoscale object by Cyrus C.M. Mody and Michael Lynch (BJHS 43(3) : 423-458 September 2010.

ROUND-TABLES


IMAGES IN PUBLICATIONS

RESOLUTION

•Lateral•Sampling•Z-color scale

VIEW

•3D•Height info•Scan size•Profile•Large/small field•Topo+phase•Computer zoom

CONVOLUTION

•Std size/shape?

DATA

•RMS•Distribution

MEANING

•Why image?•Interpretation?


RESOLUTION

Fig. 2. Attractive regime tapping-mode AFM image taken inambient laboratory conditions (relative humidity 30–40%) andhigh relative set-point ratio (40.95). The sample was desiccatedover silica gel in a low vacuum (410 mbar) for a period of oneweekbefore imaging. Molecules have a continuous variation inorientation on the surface. The molecules, A–C have anorientation where the AFM tip can resolve the three 50 kDa

subunits of IgG molecules. Pixel size is 1.24 nm. The image is infalse colour with the lighter areas representing higher points onthe sample.


VIEW (1)


VIEW (2)

Fig. 4. AFM phase image for DSU-immobilized monoclonal anti-rabbit antibody (no Tween) on a GQC electrode. The resolution is shown at 50 nm/div.

30 nm 30 nm


CONVOLUTION

~100 nm

Figure2. IgG molecules immobilized on the polystyrene surface showing the characteristic heart shape

characteristic Y shape of an IgG molecule with a diameter of about 40 nm (scanning size for inset, 50 nm)


0 nm1 nm2 nm3 nm4 nm5 nm

ANTIBODY AND TIP CONVOLUTION

Adepth from Wendy CHEN


DATA


MEANING

Fig. 4. AFM topography of immobilized Fabsurface; scan range was 1 µm×1 µm.


WHAT IS CASIM?

Critical Assessment of Structure Imaging and Mechan ics

Pierre Parot initiated the idea to organize a community-wide experiment to assess the credibility and reproducibility of AFM single molecule topography and mechanical elasticity

Process:1) Collect samples (to be defined)2) Participants submit their results3) Discussion of results during a COST Workshop

standardization in afm for life sciences oct 18-19,...

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