Adverse drug reactions associated with some anticancer medicines are a significant reason for
patient compliance; therefore, healthcare providers have invested substantial effort in the last
four decades in therapeutic drug monitoring (TDM) research to maximize therapeutic results,
minimize toxicity or to achieve both of these. Therapeutic drug monitoring (TDM) is extremely
important for anticancer drugs which often have serious adverse effects and whose optimum
dosage can differ significantly between patients. Most analytical techniques applied for TDM
are chromatographic methods, such as HPLC, LC-MS and LC-MSMS. Since these current
methods have some challenges, such as time consuming, financial cost, and the need for high
skilled personnel, it was beneficial to search for better methods.
Therefore, the aim of this research to study the developing and synthesizing of an aptamer
model to approach monitoring of Lenalidomide (LDM), 6-Mercaptopurine (6-MP), Dabrafenib
(DFB) and Venetoclax (VENX) via the Sequential Evolution of Ligands by Exponential
Enrichment (SELEX) process.
In this work, DNA aptamers against four commonly used anticancer – Lenalidomide (LDM),
6-Mercaptopurine (6-MP), Dabrafenib (DFB) and Venetoclax (VENX) – have been selected,
identified and characterized through the systematic evolution of ligands by exponential
enrichment (SELEX) technique. Ten cycles of selection have been applied for each medicine.
Many different Lenalidomide, 6-Mercaptopurine, Dabrafenib and Venetoclax-specific aptamer
sequences were successfully obtained.
For the Lenalidomide, 19 aptamers were isolated, identified and aligned through SELEX and
cloning then three of these were synthesized and the binding affinity of these three candidate’s
ssDNA aptamers to Lenalidomide were individually tested by a microscale thermophoresis
(MST) technique and their dissociation constants calculated (Kd for the candidate aptamer
number 1 = 653.46 ± 0.23 nM; Kd for the candidate aptamer number 2 = 15.18 ± 0.37 nM; and
Kd for the candidate aptamer number 3 = 7.75 ± 0.09 nM). For the 6-Mercaptopurine, 10
aptamers were isolated, identified and aligned through SELEX and cloning and then three of
these were synthesized. The binding affinity of these three candidate’s ssDNA aptamers to 6-
Mercaptopurine were individually tested by microscale thermophoresis (MST) and their
dissociation constants calculated (Kd for the candidate aptamer number 1 = 2.30 ± 0.22 nM;
Kd for the candidate aptamer number 2 = 46.8 ± 0.23 nM; and Kd for the candidate aptamer
number 3 = 0.1552 ± 0.37 nM). For Dabrafenib, 28 aptamers were isolated, identified and
aligned through SELEX and cloning, then three of these were synthesized and the binding
affinity of these three candidate’s ssDNA aptamers to Dabrafenib were individually tested by
microscale thermophoresis (MST) with their dissociation constants calculated (Kd for the
candidate aptamer number 1 = 0.324 ± 0.23 nM; Kd for the candidate aptamer number 2 =
0.153 ± 0.23 nM; and Kd for the candidate aptamer number 3 = 2.016 ± 0.23 uM). Finally, for
the Venetoclax, eight aptamers were isolated, identified and aligned through SELEX and
cloning. Three of these were synthesized and the binding affinity of these three candidate’s
ssDNA aptamers to Venetoclax were individually tested by microscale thermophoresis (MST).
Their dissociation constants calculated (Kd for the candidate aptamer number 1 = 29.06 ± 0.28
nM; Kd for the candidate aptamer number 2 = 11.66 ± 0.24 nM; and Kd for the candidate
aptamer number 3 = 13.87 ± 0.29 uM). This work reports the first oligonucleotide aptamers
selected for Lenalidomide, 6-Mercaptopurine, Dabrafenib and Venetoclax with Kd in the
nanomolar range. These aptamers can be used for both basic research and clinical purposes.
The sub-nanomolar range of Kds indicate that these aptamers have very high affinity for their
respective drugs. These aptamers could be an emerging molecular recognition receptor for the
construction of highly specific and very sensitive aptamer-based biosensors for therapeutic
drug monitoring applications.
| Date of Award | 15 Dec 2025 |
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| Original language | English |
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| Awarding Institution | - University Of Strathclyde
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| Sponsors | University of Strathclyde |
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| Supervisor | Ibrahim Khadra (Supervisor) & David Watson (Supervisor) |
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