Nabi Nuzhat, Alam Javed, Riaz Ufana
Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, India.
King Abdullah Institute of Nanotechnology, Riyadh, Saudi Arabia.
Luminescence. 2025 May;40(5):e70184. doi: 10.1002/bio.70184.
In this paper, oligomers of polyaniline (PANI) modified with cysteine (Cys) were synthesized via using different mole ratios of aniline: Cysteine (80:20, 50:50, and 20:80) followed by ultrasound-assisted polymerization of PANI. The structure and morphological properties of Cys-PANI were confirmed from FTIR and scanning electron microscopy (SEM). Fluorescence quenching of bovine serum albumin (BSA) and human serum albumin (HSA) was carried out using different concentrations of the Cys-PANI oligomers. There was a slight difference in the static quenching of HSA as compared to BSA, which was attributed to the different structures of the two serum albumins. The quenching rate constant was found to increase with cysteine content in the polymer, showing that the loading of higher amount of Cys increased the solubility of the Cys-PANI oligomers. This led to electrostatic attraction between the water molecules shielding the serum albumins and the Cys-PANI oligomers. The docking studies confirmed the binding to be hydrogen bonding, π-alkyl and π-amide stacked interactions. The binding energy of the Cys-PANI oligomers with mole ratio 50:50 and 20:80 was found to be better as compared to the Cys-PANI oligomer. The binding energy values showed that these polymers could potentially be used in fabricating protein sensors.
在本文中，通过使用不同摩尔比的苯胺：半胱氨酸（80:20、50:50和20:80）合成了用半胱氨酸（Cys）修饰的聚苯胺（PANI）低聚物，随后进行聚苯胺的超声辅助聚合。通过傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）确定了Cys-PANI的结构和形态特性。使用不同浓度的Cys-PANI低聚物对牛血清白蛋白（BSA）和人血清白蛋白（HSA）进行荧光猝灭实验。与BSA相比，HSA的静态猝灭存在细微差异，这归因于两种血清白蛋白的不同结构。发现猝灭速率常数随聚合物中半胱氨酸含量的增加而增加，表明较高含量的Cys负载增加了Cys-PANI低聚物的溶解度。这导致屏蔽血清白蛋白的水分子与Cys-PANI低聚物之间产生静电吸引。对接研究证实结合为氢键、π-烷基和π-酰胺堆积相互作用。发现摩尔比为50:50和20:80的Cys-PANI低聚物的结合能比Cys-PANI低聚物更好。结合能值表明这些聚合物有可能用于制造蛋白质传感器。
