Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms

Description:

In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum conditions for ablation of biological tissues. The mutant and wildtype (control) obtained from laser cutting with a size of 500 µm × 500 µm were directly transferred (in-situ with laser cutting) into a microfabricated chamber containing ~500 nanoliters deionized water for measuring ion conductivity. The ion conductivity is a signature of cell-death mechanisms caused by various stresses. A light with intensity of 100 µmol was exposed to the samples for 2 hours and 20 minutes as a source of stress. A quantitative electrical analysis with high accuracy was assured by utilizing a microchamber, which enables a measurement in nanoliter volume. We measured the impedance which is reciprocal of conductivity using a lock-in amplifier and a precise current source at frequency of 130 Hz. Initially high impedance of mutant sample tended to drop within 2 hours and finally approached the constant value which signified that the cell death mechanism was complete. However, the wildtype sample demonstrated approximately constant impedance (conductivity) during the experiment.

Creator(s): Abtahi, Seyed Ali
Creation Date: August 2010
Partner(s):
UNT Libraries
Collection(s):
UNT Theses and Dissertations
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Total Uses: 335
Past 30 days: 4
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Publisher Info:
Publisher Name: University of North Texas
Place of Publication: Denton, Texas
Date(s):
  • Creation: August 2010
Description:

In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum conditions for ablation of biological tissues. The mutant and wildtype (control) obtained from laser cutting with a size of 500 µm × 500 µm were directly transferred (in-situ with laser cutting) into a microfabricated chamber containing ~500 nanoliters deionized water for measuring ion conductivity. The ion conductivity is a signature of cell-death mechanisms caused by various stresses. A light with intensity of 100 µmol was exposed to the samples for 2 hours and 20 minutes as a source of stress. A quantitative electrical analysis with high accuracy was assured by utilizing a microchamber, which enables a measurement in nanoliter volume. We measured the impedance which is reciprocal of conductivity using a lock-in amplifier and a precise current source at frequency of 130 Hz. Initially high impedance of mutant sample tended to drop within 2 hours and finally approached the constant value which signified that the cell death mechanism was complete. However, the wildtype sample demonstrated approximately constant impedance (conductivity) during the experiment.

Degree:
Level: Master's
Physical Description:

v, 58 p. : ill.

Language(s):
Subject(s):
Keyword(s): Femtosecond laser | cell death mechanisms | Arabidopsis | micromachining | ion conductivity
Contributor(s):
Partner:
UNT Libraries
Collection:
UNT Theses and Dissertations
Identifier:
  • OCLC: 711868502 |
  • UNTCAT: b3968615 |
  • ARK: ark:/67531/metadc31522
Resource Type: Thesis or Dissertation
Format: Text
Rights:
Access: Public
License: Copyright
Holder: Abtahi, Seyed Ali
Statement: Copyright is held by the author, unless otherwise noted. All rights reserved.