Nanotools for biosensing and manipulating cells
(2024)- Abstract
- In medical research and within the field of Biology, it is important to find effective tools for probing and manipulating cells, as well as tools for detecting biomolecules. These tools should be sensitive, with high specitivity, and, if aimed at interacting with cells, they should be minimally invasive. In this thesis, I investigated the potential of various nanotools for these purposes. Specifically, I investigated the use of
photovoltaic nanowires as a tool to manipulate cancer cells and send them to dormancy. I also evaluate the potential of using molecular beacons to sense the transcriptional state of cells with respect to a specific gene, and to detect oligonucleotides in solution. The work has been divided into three... (More) - In medical research and within the field of Biology, it is important to find effective tools for probing and manipulating cells, as well as tools for detecting biomolecules. These tools should be sensitive, with high specitivity, and, if aimed at interacting with cells, they should be minimally invasive. In this thesis, I investigated the potential of various nanotools for these purposes. Specifically, I investigated the use of
photovoltaic nanowires as a tool to manipulate cancer cells and send them to dormancy. I also evaluate the potential of using molecular beacons to sense the transcriptional state of cells with respect to a specific gene, and to detect oligonucleotides in solution. The work has been divided into three projects.
Apart from the normal cell division cycle, where cells normally prepare for division, they can also enter a dormant state. Many cancer treatments aim to kill the cancer cells at specific steps in the cell division cycle. If the cancer cells then are dormant, they can evade the treatment, resulting in reoccurring cancer and metastasis. This reveals a need for a cell dormancy switch, where cells can be forced to
enter dormancy in a controlled way in vitro. This would enable further investigation of dormancy in cells, and make it possible to study how dormant cells react to new potential treatments. Nanowires are high aspect ratio nanostructures, which are today mainly used in optoelectronic nanodevices. In this thesis, I show that cells seeded on InP p-i-n nanowires can enter dormancy when they are illuminated.
This makes the setup act as a cell dormancy switch. Through control experiments, I could conclude that the induced dormancy was due to injection of carriers into the medium surrounding the nanowires.
In this thesis, I also investigate whether molecular beacons can be used to probe for Ins-1 mRNA, and for measuring its concentration inside of beta cells. Molecular beacons are hairpin shaped chains of
nucleic acids, with a loop sequence designed to be complementary to the specific mRNA of interest. In order for molecular beacons to report the presence of mRNA in cells, they need to be injected in the cytosol. Nanostraws were used for this purpose. Nanostraws are hollow alumina nanotubes, that can be used together with electrical pulses to inject cargo into cells. In the second project of the thesis,
molecular beacons were injected to a large number of beta cells using nanostraws and the beacon signal inside cells was monitored over time using fluorescence microscopy. The results show that when the molecular beacons enter the cell, they seem to be degraded, resulting in false positive signal. This makes the assessment of mRNA in cells challenging with this method. In a third project, I show that molecular beacons can be used as a probe for oligonucleotides in solution. To amplify the molecular beacon signal upon hybridization, beacons were immobilized on light
guiding nanowires in a microchannel. Complementary oligonucleotides were added in the microchannel over the nanowires and could be detected with a limit of detection of 0.1 nM, making the setup a promising alternative to current probing methods. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/49274ffb-6fdb-4f0f-a9d3-1689ba6bcd16
- author
- Johansson, Therese LU
- supervisor
- opponent
-
- Prof. Sikorski, Pawel, Norwegian University of Science and Technology, Norway.
- organization
- publishing date
- 2024
- type
- Thesis
- publication status
- published
- subject
- keywords
- Fysicumarkivet A:2024: Johansson
- publisher
- Department of Physics, Lund University
- defense location
- Lecture Hall Rydbergsalen, Department of Physics, Sölvegatan 14, Faculty of Engineering LTH, Lund University, Lund.
- defense date
- 2024-01-12 09:15:00
- ISBN
- 978-91-8039-809-1
- 978-91-8039-810-7
- language
- English
- LU publication?
- yes
- id
- 49274ffb-6fdb-4f0f-a9d3-1689ba6bcd16
- date added to LUP
- 2023-12-11 15:24:24
- date last changed
- 2024-01-31 11:12:52
@phdthesis{49274ffb-6fdb-4f0f-a9d3-1689ba6bcd16,
abstract = {{In medical research and within the field of Biology, it is important to find effective tools for probing and manipulating cells, as well as tools for detecting biomolecules. These tools should be sensitive, with high specitivity, and, if aimed at interacting with cells, they should be minimally invasive. In this thesis, I investigated the potential of various nanotools for these purposes. Specifically, I investigated the use of<br/>photovoltaic nanowires as a tool to manipulate cancer cells and send them to dormancy. I also evaluate the potential of using molecular beacons to sense the transcriptional state of cells with respect to a specific gene, and to detect oligonucleotides in solution. The work has been divided into three projects.<br/>Apart from the normal cell division cycle, where cells normally prepare for division, they can also enter a dormant state. Many cancer treatments aim to kill the cancer cells at specific steps in the cell division cycle. If the cancer cells then are dormant, they can evade the treatment, resulting in reoccurring cancer and metastasis. This reveals a need for a cell dormancy switch, where cells can be forced to<br/>enter dormancy in a controlled way in vitro. This would enable further investigation of dormancy in cells, and make it possible to study how dormant cells react to new potential treatments. Nanowires are high aspect ratio nanostructures, which are today mainly used in optoelectronic nanodevices. In this thesis, I show that cells seeded on InP p-i-n nanowires can enter dormancy when they are illuminated.<br/>This makes the setup act as a cell dormancy switch. Through control experiments, I could conclude that the induced dormancy was due to injection of carriers into the medium surrounding the nanowires.<br/>In this thesis, I also investigate whether molecular beacons can be used to probe for Ins-1 mRNA, and for measuring its concentration inside of beta cells. Molecular beacons are hairpin shaped chains of<br/>nucleic acids, with a loop sequence designed to be complementary to the specific mRNA of interest. In order for molecular beacons to report the presence of mRNA in cells, they need to be injected in the cytosol. Nanostraws were used for this purpose. Nanostraws are hollow alumina nanotubes, that can be used together with electrical pulses to inject cargo into cells. In the second project of the thesis,<br/>molecular beacons were injected to a large number of beta cells using nanostraws and the beacon signal inside cells was monitored over time using fluorescence microscopy. The results show that when the molecular beacons enter the cell, they seem to be degraded, resulting in false positive signal. This makes the assessment of mRNA in cells challenging with this method. In a third project, I show that molecular beacons can be used as a probe for oligonucleotides in solution. To amplify the molecular beacon signal upon hybridization, beacons were immobilized on light<br/>guiding nanowires in a microchannel. Complementary oligonucleotides were added in the microchannel over the nanowires and could be detected with a limit of detection of 0.1 nM, making the setup a promising alternative to current probing methods.}},
author = {{Johansson, Therese}},
isbn = {{978-91-8039-809-1}},
keywords = {{Fysicumarkivet A:2024: Johansson}},
language = {{eng}},
publisher = {{Department of Physics, Lund University}},
school = {{Lund University}},
title = {{Nanotools for biosensing and manipulating cells}},
url = {{https://lup.lub.lu.se/search/files/166614365/Avhandling_Therese_Johansson_utan_papers.pdf}},
year = {{2024}},
}