The study of the interaction between biomolecules and nanoparticles (NPs) is interesting since the dimensions of the two overlap to some extent. Herein, the interaction of an essential amino acid, tryptophan, with Cu₂S NPs was investigated at by using various spectroscopic techniques. The 220 nm absorption band of tryptophan was found to be blue-shifted by 2 and 5 nm at pH 6 and 10.6 respectively. The binding of tryptophan with the Cu₂S NPs at pH 10.6 via its indole chromophore was established by the Fourier transform infrared (FTIR) spectroscopic measurements. The fluorescence emission of tryptophan was quenched by the semiconductor NPs. The fluorescence quenching was found to be dynamic in nature at pH 6. However, the static mode of quenching was found to be operative at pH 10.6. The binding constants and thermodynamic parameters were calculated for the tryptophan-Cu₂S NPs complex at pH 10.6.

由于生物分子和纳米颗粒（NPs）的尺寸在一定程度上重叠，因此对它们的相互作用的研究非常有趣。在此，使用各种光谱技术研究了必需氨基酸色氨酸与Cu ₂ S NPs的相互作用。发现色氨酸的220 nm吸收带分别在pH 6和10.6时蓝移了2和5 nm。色氨酸与Cu ₂的结合通过傅立叶变换红外（FTIR）光谱测量，确定了通过吲哚发色团在pH 10.6时产生的S NP。色氨酸的荧光发射被半导体NPs猝灭。发现荧光猝灭在pH 6时本质上是动态的。但是，发现猝灭的静态模式在pH 10.6下有效。计算了色氨酸-Cu ₂ S NPs复合物在pH 10.6下的结合常数和热力学参数。