Department of Radio Physics and Electronics, University of Calcutta, Kolkata 700009, India.
Technical Research Centre, S.N. Bose National Centre for Basic Sciences, Kolkata 700106, India.
Phys Chem Chem Phys. 2022 Mar 9;24(10):6176-6184. doi: 10.1039/d1cp05159h.
The potentiality of Förster resonance energy transfer (FRET) for studying molecular interactions inside biological tissues with improved spatial (Angström) and temporal (picosecond) resolution is well established. On the other hand, the efficacy of diffuse reflectance spectroscopy (DRS) that uses optical radiation in order to determine physiological parameters including haemoglobin, and oxygen saturation is well known. Here we have made an attempt to combine diffuse reflectance spectroscopy (DRS) with picosecond-resolved FRET in order to show improvement in the exploration of molecular contacts in biological tissue models. We define the technique as ultrafast time-resolved diffuse reflectance spectroscopy (UTRDRS). The illuminated photon of the fluorophore from the surface of the tissue-mimicking layers carries the hidden information of the molecular contact. In order to investigate the validation of the Kubelka-Munk (KM) formulism for the developed UTRDRS technique in tissue phantoms, we have studied the propagation of incandescent and picosecond-laser light through several layers of cellulose membranes. While picosecond-resolved FRET in the diffuse reflected light confirms the hidden nano-contact (4.6 nm) of two different dye layers (8-anilino-1-naphthalenesulfonic acid and Nile blue), high-resolution optical microscopy on the cross-section of the layers reveals the proximity and contacts of the layers with limited spatial resolution (∼300 nm). We have also investigated two biologically relevant molecules, namely carboxyfluorescein and haemoglobin, in tissue phantom layers in order to show the efficacy of the UTRDRS technique. Overall, our studies based on UTRDRS in tissue mimicking layers may have potential applications in non-invasive biomedical diagnosis for patients suffering from skin diseases.
Förster 共振能量转移（FRET）在提高空间（埃）和时间（皮秒）分辨率的情况下，具有研究生物组织内分子相互作用的潜力，这一点已得到充分证实。另一方面，利用光学辐射来确定包括血红蛋白和氧饱和度在内的生理参数的漫反射光谱（DRS）的功效也是众所周知的。在这里，我们尝试将漫反射光谱（DRS）与皮秒分辨的 FRET 相结合，以显示在生物组织模型中探索分子接触方面的改进。我们将该技术定义为超快时间分辨漫反射光谱（UTRDRS）。来自组织模拟层表面的荧光团的被照射光子携带分子接触的隐藏信息。为了研究在组织体模中开发的 UTRDRS 技术的 Kubelka-Munk（KM）公式的有效性，我们研究了白炽光和皮秒激光在几层纤维素膜中的传播。虽然漫反射光中的皮秒分辨 FRET 证实了两个不同染料层（8-苯胺-1-萘磺酸和尼罗蓝）的隐藏纳米接触（4.6nm），但对层的横截面的高分辨率光学显微镜显示了层的接近和接触，空间分辨率有限（约 300nm）。我们还在组织体模层中研究了两种与生物学相关的分子，即羧基荧光素和血红蛋白，以显示 UTRDRS 技术的功效。总体而言，我们在组织模拟层中基于 UTRDRS 的研究可能在针对患有皮肤病的患者的非侵入性生物医学诊断中具有潜在应用。
