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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 stereoscopic images captured from different angles. -5° (a), 0° (b), and 5° (c), DEM created using MeX (d). For surface texture parameters of this pipette please see Tables 3 and 5. The bar represents 10 μm.
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Figure 2: SEM stereoscopic images captured from different angles. -5° (a), 0° (b), and 5° (c), DEM created using MeX (d). For surface texture parameters of this pipette please see Tables 3 and 5. The bar represents 10 μm.

Mentions: To determine the three-dimensional structure of pipette tips, SEM stereoscopic technique was used in the investigation [17]. To capture high-quality SEM images which satisfy stereoscopic technique requirements, glass micropipettes were coated with a thin layer of platinum (< 5 nm). The SEM machine used for 3D reconstructions was "Quanta 3D FEG" (FEI, Hillsboro, OR, USA). Three SEM images were taken from different angles by tilting the stage with respect to the electron beam direction. Differences in heights of features appear as lateral displacements in every pair of SEM images and the third dimension can be calculated from the difference between right and left images. To measure the surface characteristics, Digital Elevation Model (DEM) of the tip was created by 3D reconstruction technique using a commercial software package MeX (Alicona, Graz, Austria) [18]. Figure 2 shows the SEM stereo images used in reconstruction of a pipette and its DEM.


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

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

SEM stereoscopic images captured from different angles. -5° (a), 0° (b), and 5° (c), DEM created using MeX (d). For surface texture parameters of this pipette please see Tables 3 and 5. The bar represents 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: SEM stereoscopic images captured from different angles. -5° (a), 0° (b), and 5° (c), DEM created using MeX (d). For surface texture parameters of this pipette please see Tables 3 and 5. The bar represents 10 μm.
Mentions: To determine the three-dimensional structure of pipette tips, SEM stereoscopic technique was used in the investigation [17]. To capture high-quality SEM images which satisfy stereoscopic technique requirements, glass micropipettes were coated with a thin layer of platinum (< 5 nm). The SEM machine used for 3D reconstructions was "Quanta 3D FEG" (FEI, Hillsboro, OR, USA). Three SEM images were taken from different angles by tilting the stage with respect to the electron beam direction. Differences in heights of features appear as lateral displacements in every pair of SEM images and the third dimension can be calculated from the difference between right and left images. To measure the surface characteristics, Digital Elevation Model (DEM) of the tip was created by 3D reconstruction technique using a commercial software package MeX (Alicona, Graz, Austria) [18]. Figure 2 shows the SEM stereo images used in reconstruction of a pipette and its DEM.

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