In this work we present a fast and label-free technique for biomolecules detection. The approach has been proved to be powerful to investigate small DNA mutation. Surface enhanced Raman spectroscopy (SERS) is an outstanding technique for DNA analyses by providing a specific fingerprint of chemical structure with a high sensitivity in a very short acquisition time. Homogeneous decoration of Silicon nanowires (SiNWs) by silver nanoparticles (Ag-NPs) was carried out using pulsed laser deposition (PLD) technique. SiNWs have been synthesized via metal-assisted chemical etching (MACE) method. We investigate in this work the effect of the Ag-NPs nanodecoration conditions through the variation of the laser ablation pulses number (N_LAP). Thus, the Ag-NPs decorated SiNWs were used as sensors to detect organic and biomolecules by means of Surface Enhanced Raman Spectroscopy (SERS). By varying the N_LAP, we were able to identify the optimal combination of Ag-NPs' size and surface coverage that yields the highest SERS signal. SEM images revealed well-ordered SiNWs (~2.4 μm-long and 30–60 nm diam.) with their uniform decoration by Ag-NP. High resolution-TEM analyses confirmed the effective decoration of the SiNWs by Ag-NPs of which average size is found to increase linearly from ~20 to 50 nm when the N_LAP is increased from 500 to 10,000. The Ag-NPs/SiNWs matrix shows significantly higher (150 fold) Raman signal compared to their Ag-NPs-decorated-flat‑silicon counterparts. We found that SERS efficiency is sensitive to the nanoparticles size and reaches its maximum of (1.6 × 10⁶) for the Ag-NPs having the optimal diameter of ~40 nm (obtained at N_LP = 5000). The developed sensor proved to be highly sensitive to detect upto pico-molar concentrations of R6G. These Ag-NPs/SiNWs probes were demonstrated to have outstanding potential for label free detection of DNA samples with high sensitivity and reproducibility. It was found that the developed nanohybrid sensor is able to differentiate DNAs with very small genetic sequence difference.

在这项工作中，我们提出了一种快速且无标记的生物分子检测技术。事实证明，该方法对研究小型DNA突变非常有效。表面增强拉曼光谱（SERS）是一种出色的DNA分析技术，它可以在非常短的采集时间内以高灵敏度提供化学结构的特定指纹。使用脉冲激光沉积（PLD）技术对银纳米线（Ag-NPs）进行的硅纳米线（SiNWs）均质装饰。SiNW是通过金属辅助化学蚀刻（MACE）方法合成的。我们在这项工作中通过改变激光烧蚀脉冲数（N _LAP）来研究Ag-NPs纳米修饰条件的影响）。因此，用Ag-NPs装饰的SiNW被用作传感器，通过表面增强拉曼光谱（SERS）来检测有机分子和生物分子。通过改变N _LAP，我们能够确定产生最大SERS信号的Ag-NPs大小和表面覆盖率的最佳组合。SEM图像显示出排列整齐的SiNW（直径约2.4μm，直径为30-60 nm），并且由Ag-NP均匀地装饰。高分辨率TEM分析证实了Ag-NP对SiNW的有效装饰，发现当N _LAP时，其平均尺寸从约20 nm线性增加到50 nm从500增加到10,000 与Ag-NPs装饰的扁平硅对应物相比，Ag-NPs / SiNWs矩阵显示出明显更高的拉曼信号（150倍）。我们发现，对于具有〜40 nm最佳直径（在N _LP  = 5000处获得）的Ag-NP ，SERS效率对纳米粒子的大小敏感，并达到其最大值（1.6×10 ⁶）。事实证明，开发的传感器对检测高达皮摩尔浓度的R6G高度敏感。这些Ag-NPs / SiNWs探针具有很高的灵敏度和重现性，可用于无标记的DNA样品检测。已经发现，开发的纳米杂交传感器能够以非常小的遗传序列差异来区分DNA。