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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

Average surface roughness of pipette tip (Sa) versus tip diameter (Dt). Sa is strongly dependent on Dt and has a direct correlation with it. A first degree polynomial equation fitted to data suggests that Sa can be estimated knowing the tip diameter of a given pipette with good approximation.
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Figure 8: Average surface roughness of pipette tip (Sa) versus tip diameter (Dt). Sa is strongly dependent on Dt and has a direct correlation with it. A first degree polynomial equation fitted to data suggests that Sa can be estimated knowing the tip diameter of a given pipette with good approximation.

Mentions: As it can be seen from Figures 3, 4, 5, 6 and 7, velocity has the most significant effect. A small increase in velocity significantly decreases Dt and Sa. The effects of pull and heat are very similar and not as significant as the effect of velocity. Delay and pressure are factors to change the taper length of the pipettes while keeping the tip size unchanged [16]. Increasing delay and pressure will result in a shorter taper. Although these two factors do not change tip diameter significantly, it can be seen from Figures 6 and 7 that the bigger pipette has a higher surface roughness. From Figures 3, 4, 5, 6 and 7 it can be understood that Dt and Sa have direct correlation. Figure 8 is obtained by plotting Dt versus Sa for 21 pipettes pulled with different pulling parameters. It can be seen that average surface roughness of pipette is strongly related to tip size. Dt and Sa have direct correlation, i.e., by increasing the tip size, surface roughness also increases.


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

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

Average surface roughness of pipette tip (Sa) versus tip diameter (Dt). Sa is strongly dependent on Dt and has a direct correlation with it. A first degree polynomial equation fitted to data suggests that Sa can be estimated knowing the tip diameter of a given pipette with good approximation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 8: Average surface roughness of pipette tip (Sa) versus tip diameter (Dt). Sa is strongly dependent on Dt and has a direct correlation with it. A first degree polynomial equation fitted to data suggests that Sa can be estimated knowing the tip diameter of a given pipette with good approximation.
Mentions: As it can be seen from Figures 3, 4, 5, 6 and 7, velocity has the most significant effect. A small increase in velocity significantly decreases Dt and Sa. The effects of pull and heat are very similar and not as significant as the effect of velocity. Delay and pressure are factors to change the taper length of the pipettes while keeping the tip size unchanged [16]. Increasing delay and pressure will result in a shorter taper. Although these two factors do not change tip diameter significantly, it can be seen from Figures 6 and 7 that the bigger pipette has a higher surface roughness. From Figures 3, 4, 5, 6 and 7 it can be understood that Dt and Sa have direct correlation. Figure 8 is obtained by plotting Dt versus Sa for 21 pipettes pulled with different pulling parameters. It can be seen that average surface roughness of pipette is strongly related to tip size. Dt and Sa have direct correlation, i.e., by increasing the tip size, surface roughness also increases.

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