Fourier transform infrared spectroscopy imaging (FTIRSI) combined with spectral analysis and polarization approach was creatively used to investigate both structures of bilirubin (BR) precipitate and BR aggregate at liquid-liquid interface. It was found by spectral analysis that the internal hydrogen bonds of BR molecules all broke and the dihedral angles increased during the formation of BR aggregate at liquid-liquid interface. And the BR molecule might be of layer assembly along the long axis direction of CD half-group to form J-type aggregates, which could be parallel to the direction of the transition dipole moment of BR aggregate. The further study of polarized imaging/anisotropy revealed that the absorbance of 1570 and 1703 cm⁻¹ bands of BR aggregate changed periodically at intervals of 90°, which were not shown in BR precipitate case, indicating that the CC of the corresponding lactam ring and the CO of the adjacent carboxyl groups formed ordered arrangement in BR aggregate. It also suggested that the two positions might be the active sites which J-type aggregates assembled on. The combined technique was firstly applied in interfacial aggregate research, which was helpful for further understanding and controlling the aggregation as well as structural transformation of BR molecules so as to decrease physiological hazard and facilitate the wide spread application in biomedicine.

傅里叶变换红外光谱成像（FTIRSI）结合光谱分析和极化方法被创造性地用于研究液-液界面处胆红素（BR）沉淀物和BR聚集体的结构。通过光谱分析发现，在液-液界面处的BR聚集体形成过程中，BR分子的内部氢键全部断裂，二面角增加。BR分子可能沿CD半基团的长轴方向成层组装，形成J型聚集体，可以与BR聚集体的跃迁偶极矩方向平行。偏振成像/各向异性的进一步研究表明，吸光度为1570和1703 cm ^-1BR聚集体的能带以90°的间隔周期性变化，这在BR沉淀情况下未显示，表明相应的内酰胺环的C C和相邻羧基的C O在BR聚集体中形成有序排列。这也表明这两个位置可能是J型聚集体聚集在其上的活性位点。结合技术首先应用于界面聚集体研究，有助于进一步了解和控制BR分子的聚集以及结构转化，从而降低生理危害，促进其在生物医学中的广泛应用。