Rapid and cost-effective quantitative analysis of arsenic in drinking water using surface-enhanced Raman spectroscopy

A rapid, cost-effective, and sample-preparation-free approach is proposed for the quantitative detection of arsenic in drinking water, using surface-enhanced Raman spectroscopy (SERS). This fabrication entailed comprehensive optimization of chemically synthesized silver colloidal nanoparticles, focusing on parameters such as centrifugation time and speed to attain maximal nanoparticle concentration while mitigating interference from trisodium citrate and other chemical agents. Subsequently, SERS substrates were fabricated by depositing a concentrated drop of colloidal silver nanoparticles onto hydrophobic silicon substrates using the drop-coating technique. The drying process induced a coffee-ring effect, resulting in a pronounced spatial variation of nanoparticle concentration, with significantly higher densities observed in the peripheral ring regions compared to the central regions of the substrate. These regions possess the ability to enhance the Raman spectrum of arsenic, enabling the detection of arsenic at concentrations as low as 50 ppb. This method can prove highly valuable for initial field analyses of drinking water

Correlative Raman Imaging: Development and Cancer Applications

Despite extensive research efforts, cancer continues to stand as one of the leading causes of death on a global scale. To gain profound insights into the intricate mechanisms underlying cancer onset and progression, it is imperative to possess methodologies that allow the study of cancer cells at the single-cell level, focusing on critical parameters such as cell morphology, metabolism, and molecular characteristics. These insights are essential for effectively discerning between healthy and cancerous cells and comprehending tumoral progression. Recent advancements in microscopy techniques have significantly advanced the study of cancer cells, with Raman microspectroscopy (RM) emerging as a particularly powerful tool. Indeed, RM can provide both biochemical and spatial details at the single-cell level without the need for labels or causing disruptions to cell integrity. Moreover, RM can be correlated with other microscopy techniques, creating a synergy that offers a spectrum of complementary insights into cancer cell morphology and biology. This review aims to explore the correlation between RM and other microscopy techniques such as confocal fluoresce microscopy (CFM), atomic force microscopy (AFM), digital holography microscopy (DHM), and mass spectrometry imaging (MSI). Each of these techniques has their own strengths, providing different perspectives and parameters about cancer cell features. The correlation between information from these various analysis methods is a valuable tool for physicians and researchers, aiding in the comprehension of cancer cell morphology and biology, unraveling mechanisms underlying cancer progression, and facilitating the development of early diagnosis and/or monitoring cancer progression