Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Molecules. 2023 Feb 12;28(4):1745. doi: 10.3390/molecules28041745.
A comparative investigation of amino acids (proline, cysteine, and alanine) as dosimetric materials using electron paramagnetic resonance (EPR) spectroscopy in the absorbed dosage range of 1-25 kGy is presented. There were no signals in the EPR spectra of the samples before irradiation. After irradiation, the complex spectra were recorded. These results showed that the investigated amino acids were sensitive to radiation. In the EPR spectrum of cysteine after irradiation, RS• radicals dominated. The effects of the microwave power on the saturation of the EPR signals showed the presence of at least three different types of free radicals in proline. It was also found out that the DL-proline and cysteine had stable free radicals after irradiation and represented a linear dosage response up to 10 kGy. On the other hand, the amino acid alanine has been accepted by the International Atomic Energy Agency as a transfer standard dosimetry system. In view of this, the obtained results of the proline and cysteine studies have been compared with those of the alanine studies. The results showed that the amino acids proline and cysteine could be used as alternative dosimetric materials in lieu of alanine in a dosage range of 1-10 kGy of an absorbed dose of γ-rays using EPR spectroscopy. Regarding the radiation sensitivity, the following order of decreased dosage responses was determined: alanine > DL-proline > cysteine > L-proline.
本研究采用电子顺磁共振波谱（EPR）技术，在 1-25 kGy 的吸收剂量范围内，对比研究了脯氨酸、半胱氨酸和丙氨酸三种氨基酸作为剂量学材料的性能。辐照前，样品的 EPR 光谱中没有信号。辐照后，记录到了复杂的光谱。结果表明，所研究的氨基酸对辐射很敏感。在丙氨酸的 EPR 光谱中，RS•自由基占主导地位。微波功率对 EPR 信号饱和的影响表明，脯氨酸中至少存在三种不同类型的自由基。此外，还发现辐照后 DL-脯氨酸和半胱氨酸产生了稳定的自由基，在 10 kGy 剂量范围内具有线性剂量响应。另一方面，丙氨酸已被国际原子能机构（IAEA）接受为转移标准剂量测定系统。因此，将脯氨酸和半胱氨酸的研究结果与丙氨酸的研究结果进行了比较。结果表明，在 1-10 kGy 的 γ 射线吸收剂量范围内，EPR 光谱技术可以将脯氨酸和半胱氨酸作为丙氨酸的替代剂量学材料。就辐射敏感性而言，确定了以下剂量响应降低的顺序：丙氨酸＞DL-脯氨酸＞半胱氨酸＞L-脯氨酸。
