Microfabricated Electrochemical Sensor for the Detection of Radiation-Induced DNA Damage

Abstract

An electrochemical biosensor protocol for the detection of radiation-induced DNA damage is described. The procedure employs a dsDNA-coated screen-printed electrode and relies on changes in the guanine-DNA oxidation signal upon exposure to ultraviolet radiation. The decreased signal is ascribed primarily to conformational changes in the DNA and to the photoconversion of the guanine-DNA moiety to a nonelectroactive monomeric base product. Factors influencing the response of these microfabricated DNA sensors, such as irradiation time, wavelength, and distance, are explored, and future prospects are discussed. Similar results are given for the use of bare strip electrodes in connection with irradiated DNA solutions.

Electrochemical Sensors for DNA Interactions and Damage

“…On the other hand, techniques based on measurements of changes in the intensity of a signal yielded by intact DNA are in nature less sensitive, because the change in peak height should exceed standard deviation of the measurement (usually 5 ± 10% depending on the electrode material, surface pretreatment and DNA immobilization procedure). This means that when, e.g., peak G ox is measured at carbon electrodes [12,65,67,81,85,107,123], a portion of the lesions has to be at least about 10% of total G residues to achieve reliable response of the sensor. Regarding specificity, the best results can be obtained when signals derived from electroactivity of substances interacting with DNA are measured [8, 9, 12, 35, 52, 66, 102 ± 104, 131, 143, 144, 155].…”

“…Photoexcitation of DNA bases may lead to a number of reaction products, including photohydrates, pyrimidine dimers [1,30,90] or purine degradation products such as 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua) [123]. Electrochemical properties of monomeric pyrimidine and purine photoadducts at mercury electrodes were studied by Czochralska et al [124,125].…”

“…Changes in electrochemical behavior of calf thymus dsDNA upon irradiation with UV light were detected by means of DPP [90]. Wang et al constructed a microfabricated screenprinted electrode-based DNA sensor responding to UV radiation-induced damage to guanine residues [123]. Guanine oxidation signal decreased as a result of rupture of the G imidazole ring (with concomitant loss of the G oxidation center) in a UV radiation dose-dependent manner.…”

Electrochemistry of Nucleic Acids at Solid Electrodes and Its Applications

“…Use of ultramicroelectrodes would enable application to all type of tissues minimizing tissue damage and to controlled delivery to very small spaces [42]. [138] Charge migration through DNA might be responsible for promoting rapid electron transfer between different electrode surfaces and redox enzymes and proteins such as hemoglobin and myoglobin [153,154], cytochrome c [155 ± 157] or horseradish peroxidase (HRP) [158,159]. A reagentless nitric oxide biosensor based on hemoglobin-DNA films [154] and an HRP-DNA-based biosensor for phenol determination [153], have thus been developed.…”

Comparison of Hemoglobin and Myoglobin for In Situ Metabolite Generation in Chemical Toxicity Sensors Using a Metallopolymer Catalyst for DNA Damage Detection

“…Nucleic acids can also be oxidized on solid electrodes [18] such as glassy carbon and pyrolytic graphite. Damage from ionizing radiation to DNA adsorbed onto carbon electrodes was detected by chronopotentiometry [19].…”