Mehta Megha, Skinner William, Gardner Benjamin, Mosca Sara, Palombo Francesca, Matousek Pavel, Stone Nick
Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, U.K.
Central Laser Facility, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, UKRI, Harwell Campus, Oxfordshire OX11 0QX, U.K.
ACS Omega. 2025 Jan 28;10(5):4588-4598. doi: 10.1021/acsomega.4c08791. eCollection 2025 Feb 11.
In this work, we demonstrate the synthesis of gold nanoraspberries (AuNRB) using a HEPES buffer at room temperature. The study aimed to identify and compare the physicochemical conditions of the AuNRB and gold nanospheres (AuNS) of similar size to a selected set of reporter molecules. The dispersion stability of shape-controlled and AuNS of similar diameters was investigated in three different physiological media, ultrapure water, phosphate-buffered saline (PBS), and fetal bovine serum (FBS), and compared to understand the effect of NP shape, dispersion stability, and surface-enhanced Raman scattering (SERS) enhancement. We have used two nonresonant reporters, trans-1,2-bis(4-pyridyl) ethylene (BPE) and biphenyl-4-thiol (BPT), and a resonant reporter, IR820 (also known as new indocyanine green), a clinically approved dye for diagnostic studies, to explore the relative benefit of using molecular electronic resonance, i.e., comparing SERS vs surface-enhanced resonance Raman scattering (SERRS) with these nanoparticles. SERS has been explored extensively for biomedical applications, but the synthesis of bright gold nanoparticles and the appropriate Raman label is still challenging. To understand and optimize the SERS process, we have characterized both types of gold nanoparticles, ranging from their average size, ζ-potential, and ultraviolet-visible (UV-vis) absorption. It has been found that AuNRB and AuNS are most stable when dispersed in ultrapure water, while significant aggregation of both types has been observed when dispersed in PBS. With 10% FBS, there was a slight shift and increase in the surface plasmon absorbance peak, which resulted from an increase in particle size due to protein corona formation around the gold nanoparticles. For SERS efficiency, it has been found that AuNRB outperform AuNS with all reporters. Further, the resonant reporter, IR820, has provided a higher SERS signal compared to BPE and BPT and with its FDA approval for clinical use is clearly a strong candidate for future application.
在这项工作中，我们展示了在室温下使用HEPES缓冲液合成金纳米覆盆子（AuNRB）。该研究旨在确定并比较与一组选定的报告分子大小相似的AuNRB和金纳米球（AuNS）的物理化学条件。研究了形状可控且直径相似的AuNS在三种不同生理介质（超纯水、磷酸盐缓冲盐水（PBS）和胎牛血清（FBS））中的分散稳定性，并进行比较以了解纳米颗粒形状、分散稳定性和表面增强拉曼散射（SERS）增强的影响。我们使用了两种非共振报告分子，反式-1,2-双（4-吡啶基）乙烯（BPE）和联苯-4-硫醇（BPT），以及一种共振报告分子IR820（也称为新型吲哚菁绿，一种临床批准用于诊断研究的染料），以探索使用分子电子共振的相对优势，即比较这些纳米颗粒的SERS与表面增强共振拉曼散射（SERRS）。SERS已被广泛用于生物医学应用，但合成明亮的金纳米颗粒和合适的拉曼标记仍然具有挑战性。为了理解和优化SERS过程，我们对两种类型的金纳米颗粒进行了表征，包括它们的平均尺寸、ζ电位和紫外可见（UV-vis）吸收。已发现AuNRB和AuNS分散在超纯水中时最稳定，而分散在PBS中时两种类型均观察到显著聚集。在含有10% FBS的情况下，表面等离子体吸收峰出现轻微位移并增加，这是由于金纳米颗粒周围形成蛋白质冠导致粒径增大所致。对于SERS效率，已发现使用所有报告分子时AuNRB的性能均优于AuNS。此外，共振报告分子IR820与BPE和BPT相比提供了更高的SERS信号，并且其已获得FDA批准用于临床，显然是未来应用的有力候选者。
