Electrochemically deposited silver detection substrate for surface-enhanced Raman spectroscopy cancer diagnostics

Combined miR-181a-5p and Ag Nanoparticles are Effective Against Oral Cancer in a Mouse Model

Purpose

Oral squamous cell carcinoma is the most common type of malignant tumor in the head and neck region. Despite advancements, metastasis and recurrence rates remain high, and patient survival has not significantly improved. Although miRNA therapies are promising for cancer gene therapy, their applications in treating oral cancer are limited. Targeted medication delivery systems based on nanotechnology offer an efficient way to enhance oral cancer treatment efficacy.

Methods

We synthesized nanosilver (AgNPs) and loaded them with the tumor suppressor miR-181a-5p. In vitro experiments were conducted to investigate the inhibitory effects of AgNPs and their composites on the malignant behavior of oral cancer cell lines. The xenograft experiment was utilized to examine their effects on tumorigenesis and the potential molecular mechanisms involved.

Results

The nanosilver exhibited a spherical morphology with a size distribution ranging from 50 to 100 nm. They exhibited a distinct absorption peak at 330 nm and could be excited to emit green fluorescence. The biocompatible AgNPs effectively shielded miRNA from degradation by RNase and serum. The nanocomposites significantly inhibited the proliferation, invasion, migration, and colony formation of oral cancer cell lines. Notably, treatment with the nanocomposites resulted in substantial tumor growth suppression in the xenograft model. Mechanistically, these composites directly targeted BCL2 and exerted their antitumor effects by suppressing the β-catenin signaling pathway and other downstream genes without inducing acute toxicity.

Conclusion

Collectively, the findings demonstrate that the miR-181a-5p/AgNPs combination significantly impedes the growth and progression of oral cancer both in vitro and in vivo, highlighting a pivotal role for the β-catenin signaling pathway. This multifaceted approach holds promise as a prospective therapeutic strategy for oral cancer management in the future.

Label-Free Sensing with Metal Nanostructure-Based Surface-Enhanced Raman Spectroscopy for Cancer Diagnosis

Surface-Enhanced Raman Spectroscopy (SERS) is a powerful analytical technique for the detection of small analytes with great potential for medical diagnostic applications. Its high sensitivity and excellent molecular specificity, which stems from the unique fingerprint of molecular species, have been applied toward the detection of different types of cancer. The noninvasive and rapid detection offered by SERS highlights its applicability for point-of-care (PoC) deployment for cancer diagnosis, screening, and staging, as well as for predicting tumor recurrence and treatment monitoring. This review provides an overview of the progress in label-free (direct) SERS-based chemical detection for cancer diagnosis with the main focus on the advances in the design and preparation of SERS substrates on the basis of metal nanoparticle structures formed via bottom-up strategies. It begins by introducing a synopsis of the working principles of SERS, including key chemometric approaches for spectroscopic data analysis. Then it introduces the advances of label-free sensing with SERS in cancer diagnosis using biofluids (blood, urine, saliva, sweat) and breath as the detection media. In the end, an outlook of the advances and challenges in cancer diagnosis via SERS is provided.

Promoting identification of amyotrophic lateral sclerosis based on label-free plasma spectroscopy

Objective

Amyotrophic lateral sclerosis (ALS) is an adult‐onset fatal neurodegenerative disease which lacks identified biological markers. A label‐free plasma surface‐enhanced Raman spectroscopy (SERS) method was developed to explore a simple and noninvasive test for ALS.

Methods

ALS patients were enrolled serially and plasma samples were collected at the time of diagnosis prior to the start of ALS treatment. SERS spectra were recorded using a Renishaw micro‐Raman system.

Results

To exclude the interference by varying disease severity, we enrolled three groups of ALS patients, including ALS‐1 (n = 60; ALSFRS‐R ≥ 42 and time interval ≤ 12 months), ALS‐2 (n = 61; ALSFRS‐R < 42 and time interval ≤ 12 months), and ALS‐3 (n = 61; ALSFRS‐R ≥ 38 and time interval> 12 months). The SERS spectra were analyzed using principal component analysis (PCA), which showed that ALS‐1, ALS‐2, ALS‐3, and control groups were separated significantly. Then, decision tree (DT) models and receiver operating characteristic curves were employed and identified that bands at 722 and 739 cm⁻¹, and ratios of 635–722 cm⁻¹ and 635–739 cm⁻¹ were able to distinguish ALS from controls significantly. Finally, we highlighted six metabolism pathways correlated with ALS, including phenylalanine‐tyrosine‐tryptophan biosynthesis, aminoacyl‐tRNA biosynthesis, phenylalanine metabolism, pantothenate and CoA biosynthesis, porphyrin and chlorophyll metabolism, and pyrimidine metabolism.

Interpretation:

Plasma SERS could be a promising tool for the detection of ALS. The bands at 722 and 739 cm⁻¹, and the ratios of 635–722 cm⁻¹ and 635–739 cm⁻¹ could serve as potential indicator for ALS.

Gold and silver nanoparticles used for SERS detection of S. aureus and E. coli

Surface enhanced Raman scattering (SERS) is emerging as a robust analytical method used in sensing applications in chemical as well as biological systems. SERS has been reported to be used in fast detection of micro-organisms up to the specificity of strain identification. However, use of SERS is tricky because of difficulties involved in selection of SERS active substrate so as to give uniform, sensitive as well as reproducible results. We have synthesized silver and gold nanoparticles using chemical, electrochemical and microwave-assisted methods followed by their characterization. Uses of these nanoparticles in association with micro-organisms such as S. aureus and E. coli have been analyzed using SERS to generate signature spectra. This demonstrates use of so synthesized gold and silver nanoparticles as SERS active substrates for rapid detection of micro-organisms which pave way to find applications in disease diagnostics.