Das Sathi, Tinguely Jean-Claude, Obuobi Sybil Akua Okyerewa, Škalko-Basnet Nataša, Saxena Kanchan, Ahluwalia Balpreet Singh, Mehta Dalip Singh
Bio-photonics and Green Photonics Laboratory, Indian Institute of Technology Delhi, Hauz-Khas, New Delhi 110016, India.
Department of Physics and Technology, UiT The Arctic University of Norway, Tromsø 9037, Norway.
Biomed Opt Express. 2024 Mar 12;15(4):2293-2307. doi: 10.1364/BOE.517471. eCollection 2024 Apr 1.
Programmable nanoscale carriers, such as liposomes and DNA, are readily being explored for personalized medicine or disease prediction and diagnostics. The characterization of these nanocarriers is limited and challenging due to their complex chemical composition. Here, we demonstrate the utilization of surface-enhanced Raman spectroscopy (SERS), which provides a unique molecular fingerprint of the analytes while reducing the detection limit. In this paper, we utilize a silver coated nano-bowl shaped polydimethylsiloxane (PDMS) SERS substrate. The utilization of nano-bowl surface topology enabled the passive trapping of particles by reducing mobility, which results in reproducible SERS signal enhancement. The biological nanoparticles' dwell time in the nano-trap was in the order of minutes, thus allowing SERS spectra to remain in their natural aqueous medium without the need for drying. First, the geometry of the nano-traps was designed considering nanosized bioparticles of 50-150 nm diameter. Further, the systematic investigation of maximum SERS activity was performed using rhodamine 6 G as a probe molecule. The potential of the optimized SERS nano-bowl is shown through distinct spectral features following surface- (polyethylene glycol) and bilayer- (cholesterol) modification of empty liposomes of around 140 nm diameter. Apart from liposomes, the characterization of the highly crosslinked DNA specimens of only 60 nm in diameter was performed. The modification of DNA gel by liposome coating exhibited unique signatures for nitrogenous bases, sugar, and phosphate groups. Further, the unique sensitivity of the proposed SERS substrate displayed distinct spectral signatures for DNA micelles and drug-loaded DNA micelles, carrying valuable information to monitor drug release. In conclusion, the findings of the spectral signatures of a wide range of molecular complexes and chemical morphology of intra-membranes in their natural state highlight the possibilities of using SERS as a sensitive and instantaneous characterization alternative.
可编程纳米级载体，如脂质体和DNA，正被广泛探索用于个性化医疗或疾病预测与诊断。由于这些纳米载体的化学成分复杂，对其进行表征具有一定局限性且颇具挑战性。在此，我们展示了表面增强拉曼光谱（SERS）的应用，它能提供分析物独特的分子指纹图谱，同时降低检测限。在本文中，我们使用了一种镀银的纳米碗状聚二甲基硅氧烷（PDMS）SERS基底。纳米碗表面拓扑结构的利用通过降低粒子迁移率实现了对粒子的被动捕获，从而带来可重复的SERS信号增强。生物纳米粒子在纳米阱中的停留时间为几分钟，因此无需干燥就能在其自然水性介质中获取SERS光谱。首先，在设计纳米阱的几何形状时考虑了直径为50 - 150 nm的纳米级生物粒子。此外，使用罗丹明6G作为探针分子对最大SERS活性进行了系统研究。通过对直径约140 nm的空脂质体进行表面（聚乙二醇）和双层（胆固醇）修饰后的独特光谱特征，展示了优化后的SERS纳米碗的潜力。除了脂质体，还对直径仅60 nm的高度交联DNA样本进行了表征。脂质体包被对DNA凝胶的修饰展现出了含氮碱基、糖和磷酸基团的独特特征。此外，所提出的SERS基底的独特灵敏度显示出DNA胶束和载药DNA胶束的独特光谱特征，为监测药物释放提供了有价值的信息。总之，对一系列分子复合物的光谱特征以及天然状态下膜内化学形态的研究结果突出了将SERS用作灵敏且即时表征方法的可能性。
