Liyanage Thakshila, Masterson Adrianna N, Hati Sumon, Ren Greta, Manicke Nicholas E, Rusyniak Daniel E, Sardar Rajesh
Department Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, USA.
Analyst. 2020 Nov 23;145(23):7662-7672. doi: 10.1039/d0an01372b.
Herein we report the programmable preparation of ultrasensitive surface-enhanced Raman scattering (SERS)-based nanoplasmonic superlattice substrates to assay fentanyl and cocaine (detection and quantification) from 10 μL aliquots of emergency department patient plasma without the need for purification steps. Highly homogeneous three-dimensional (3D) nanoplasmonic superlattices are generated through the droplet evaporation-based self-assembly process of chemically-synthesized, polyethylene glycol thiolate-coated gold triangular nanoprisms (Au TNPs). Close-packed, solid-state 3D superlattice substrates produce electromagnetic hot spots due to near-field plasmonic coupling of Au TNPs, which display unique localized surface plasmonic resonance properties. These uniquely prepared superlattice substrates enable strong SERS enhancement to achieve a parts-per-quadrillion limit of detection using the label-free SERS-based technique. Our reported limit of detection is at least 100-fold better than any known SERS substrates for the drug assay. Importantly, our density functional theory calculations show that a specific electronic interaction between the drug molecule and novel nanoplasmonic superlattice substrates plays a critical role that may trigger achieving this unprecedentedly high sensitivity. Additionally, we show high selectivity of the superlattice substrate in the SERS-based detection of analytes from different patient samples, which do and do not contain target analytes (i.e., fentanyl and/or cocaine). The demonstrated sensitivity and selectivity of 3D superlattice substrates for SERS-based drug analysis in real toxicological samples are expected to advance the field of measurement science, and forensic and clinical toxicology by obviating the need for complicated sample processing steps, long assay times, and the low sensitivity of existing "gold standard" analytical techniques including gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry and enzyme-linked immunosorbent assays. Taken together, we believe that this entirely new and reproducible superlattice substrate for the SERS analysis will aid scientific, forensic, and healthcare communities to battle the drug overdose epidemic in the United States.
在此，我们报告了基于超灵敏表面增强拉曼散射（SERS）的纳米等离子体超晶格基底的可编程制备方法，用于检测和定量急诊科患者10 μL血浆样本中的芬太尼和可卡因，无需进行纯化步骤。通过化学合成的聚乙二醇硫醇盐包覆的金三角形纳米棱镜（Au TNP）基于液滴蒸发的自组装过程，生成了高度均匀的三维（3D）纳米等离子体超晶格。紧密堆积的固态3D超晶格基底由于Au TNP的近场等离子体耦合而产生电磁热点，展现出独特的局域表面等离子体共振特性。这些独特制备的超晶格基底能够实现强大的SERS增强，从而使用基于无标记SERS的技术达到千万亿分之一的检测限。我们报道的检测限比任何已知用于药物检测的SERS基底至少好100倍。重要的是，我们的密度泛函理论计算表明，药物分子与新型纳米等离子体超晶格基底之间的特定电子相互作用起着关键作用，这可能是实现这种前所未有的高灵敏度的原因。此外，我们展示了超晶格基底在基于SERS的不同患者样本分析物检测中的高选择性，这些样本含有或不含有目标分析物（即芬太尼和/或可卡因）。3D超晶格基底在实际毒理学样本中基于SERS的药物分析所展示的灵敏度和选择性，有望推动测量科学以及法医和临床毒理学领域的发展，因为它无需复杂的样本处理步骤、较长的检测时间，并且克服了包括气相色谱/质谱、液相色谱/质谱和酶联免疫吸附测定等现有“金标准”分析技术的低灵敏度问题。综上所述，我们相信这种用于SERS分析的全新且可重复的超晶格基底将有助于科学界、法医界和医疗界应对美国的药物过量流行问题。
