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Surface properties of glass micropipettes and their effect on biological studies.

Malboubi M, Gu Y, Jiang K - Nanoscale Res Lett (2011)

Bottom Line: It is found that surface roughness parameters are strongly related on the tip size.The results of the experiments show that polished pipettes make significantly better seals.The results of this work are of important reference value for achieving pipettes with desired surface properties and can be used to explain biological phenomenon such as giga-seal formation.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Mechanical Engineering, The University of Birmingham, Edgbaston, Birmingham, B15 2TT UK. mlb@contacts.bham.ac.uk.

ABSTRACT
In this paper, an investigation on surface properties of glass micropipettes and their effect on biological applications is reported. Pipettes were pulled under different pulling conditions and the effect of each pulling parameter was analyzed. SEM stereoscopic technique was used to reveal the surface roughness properties of pipette tip and pipette inner wall in 3D. More than 20 pipettes were reconstructed. Pipette heads were split open using focused ion beam (FIB) milling for access to the inner walls. It is found that surface roughness parameters are strongly related on the tip size. Bigger pipettes have higher average surface roughness and lower developed interfacial area ratio. Furthermore, the autocorrelation of roughness model of the inner surface shows that the inner surface does not have any tendency of orientation and is not affected by pulling direction. To investigate the effect of surface roughness properties on biological applications, patch-clamping tests were carried out by conventional and FIB-polished pipettes. The results of the experiments show that polished pipettes make significantly better seals. The results of this work are of important reference value for achieving pipettes with desired surface properties and can be used to explain biological phenomenon such as giga-seal formation.

No MeSH data available.


Related in: MedlinePlus

SEM images of pipette before (a) and after (b) FIB milling. Notice that milled surface is much smoother than the original unmodified surface.
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Figure 9: SEM images of pipette before (a) and after (b) FIB milling. Notice that milled surface is much smoother than the original unmodified surface.

Mentions: Further investigation was conducted for measuring the inner wall surface roughness properties of glass micropipettes. Two pipettes with different sizes (Dt = 13 and 9 μm) were chosen. The pipettes were split and cut open using focused ion beam milling for access to the inner walls. The imaging direction was perpendicular to the cutting plane, avoiding redeposition of sputtered materials from the FIB cutting to the area. After cutting, the pipettes were turned 90° by means of a holder which was previously fabricated. Three SEM images were taken from the inside wall and 3D structures of the inner wall were obtained using MeX software. Figures 9 and 10 show an FIB-milled pipette and stereo images. Table 4 shows inner surface properties of small and big pipettes. The small pipette has a lower Sa and higher Sdr. To determine the effect of pulling direction on surface texture of pipette inner wall, autocorrelation of roughness model for the pipette inner surface is obtained. The autocorrelation plot, Figure 11, suggests that the surface does not have any tendency of orientation and is not affected by pulling direction.


Surface properties of glass micropipettes and their effect on biological studies.

Malboubi M, Gu Y, Jiang K - Nanoscale Res Lett (2011)

SEM images of pipette before (a) and after (b) FIB milling. Notice that milled surface is much smoother than the original unmodified surface.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211496&req=5

Figure 9: SEM images of pipette before (a) and after (b) FIB milling. Notice that milled surface is much smoother than the original unmodified surface.
Mentions: Further investigation was conducted for measuring the inner wall surface roughness properties of glass micropipettes. Two pipettes with different sizes (Dt = 13 and 9 μm) were chosen. The pipettes were split and cut open using focused ion beam milling for access to the inner walls. The imaging direction was perpendicular to the cutting plane, avoiding redeposition of sputtered materials from the FIB cutting to the area. After cutting, the pipettes were turned 90° by means of a holder which was previously fabricated. Three SEM images were taken from the inside wall and 3D structures of the inner wall were obtained using MeX software. Figures 9 and 10 show an FIB-milled pipette and stereo images. Table 4 shows inner surface properties of small and big pipettes. The small pipette has a lower Sa and higher Sdr. To determine the effect of pulling direction on surface texture of pipette inner wall, autocorrelation of roughness model for the pipette inner surface is obtained. The autocorrelation plot, Figure 11, suggests that the surface does not have any tendency of orientation and is not affected by pulling direction.

Bottom Line: It is found that surface roughness parameters are strongly related on the tip size.The results of the experiments show that polished pipettes make significantly better seals.The results of this work are of important reference value for achieving pipettes with desired surface properties and can be used to explain biological phenomenon such as giga-seal formation.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Mechanical Engineering, The University of Birmingham, Edgbaston, Birmingham, B15 2TT UK. mlb@contacts.bham.ac.uk.

ABSTRACT
In this paper, an investigation on surface properties of glass micropipettes and their effect on biological applications is reported. Pipettes were pulled under different pulling conditions and the effect of each pulling parameter was analyzed. SEM stereoscopic technique was used to reveal the surface roughness properties of pipette tip and pipette inner wall in 3D. More than 20 pipettes were reconstructed. Pipette heads were split open using focused ion beam (FIB) milling for access to the inner walls. It is found that surface roughness parameters are strongly related on the tip size. Bigger pipettes have higher average surface roughness and lower developed interfacial area ratio. Furthermore, the autocorrelation of roughness model of the inner surface shows that the inner surface does not have any tendency of orientation and is not affected by pulling direction. To investigate the effect of surface roughness properties on biological applications, patch-clamping tests were carried out by conventional and FIB-polished pipettes. The results of the experiments show that polished pipettes make significantly better seals. The results of this work are of important reference value for achieving pipettes with desired surface properties and can be used to explain biological phenomenon such as giga-seal formation.

No MeSH data available.


Related in: MedlinePlus