Combined SERS-Raman screening of HER2-overexpressing or silenced breast cancer cell lines.

BACKGROUND: Breast cancer (BC) is a heterogeneous neoplasm characterized by several subtypes. One of the most aggressive with high metastasis rates presents overexpression of the human epidermal growth factor receptor 2 (HER2). A quantitative evaluation of HER2 levels is essential for a correct diagnosis, selection of the most appropriate therapeutic strategy and monitoring the response to therapy. RESULTS: In this paper, we propose the synergistic use of SERS and Raman technologies for the identification of HER2 expressing cells and its accurate assessment. To this end, we selected SKBR3 and MDA-MB-468 breast cancer cell lines, which have the highest and lowest HER2 expression, respectively, and MCF10A, a non-tumorigenic cell line from normal breast epithelium for comparison. The combined approach provides a quantitative estimate of HER2 expression and visualization of its distribution on the membrane at single cell level, clearly identifying cancer cells. Moreover, it provides a more comprehensive picture of the investigated cells disclosing a metabolic signature represented by an elevated content of proteins and aromatic amino acids. We further support these data by silencing the HER2 gene in SKBR3 cells, using the RNA interference technology, generating stable clones further analysed with the same combined methodology. Significant changes in HER2 expression are detected at single cell level before and after HER2 silencing and the HER2 status correlates with variations of fatty acids and downstream signalling molecule contents in the context of the general metabolic rewiring occurring in cancer cells. Specifically, HER2 silencing does reduce the growth ability but not the lipid metabolism that, instead, increases, suggesting that higher fatty acids biosynthesis and metabolism can occur independently of the proliferating potential tied to HER2 overexpression. CONCLUSIONS: Our results clearly demonstrate the efficacy of the combined SERS and Raman approach to definitely pose a correct diagnosis, further supported by the data obtained by the HER2 gene silencing. Furthermore, they pave the way to a new approach to monitor the efficacy of pharmacologic treatments with the aim to tailor personalized therapies and optimize patients' outcome.

Raman Microscopy: Progress in Research on Cancer Cell Sensing.

In the last decade, Raman Spectroscopy (RS) was demonstrated to be a label-free, non-invasive and non-destructive optical spectroscopy allowing the improvement in diagnostic accuracy in cancer and analytical assessment for cell sensing. This review discusses how Raman spectra can lead to a deeper molecular understanding of the biochemical changes in cancer cells in comparison to non-cancer cells, analyzing two key examples, leukemia and breast cancer. The reported Raman results provide information on cancer progression and allow the identification, classification, and follow-up after chemotherapy treatments of the cancer cells from the liquid biopsy. The key obstacles for RS applications in cancer cell diagnosis, including quality, objectivity, number of cells and velocity of the analysis, are considered. The use of multivariant analysis, such as principal component analysis (PCA) and linear discriminate analysis (LDA), for an automatic and objective assessment without any specialized knowledge of spectroscopy is presented. Raman imaging for cancer cell mapping is shown and its advantages for routine clinical pathology practice and live cell imaging, compared to single-point spectral analysis, are debated. Additionally, the combination of RS with microfluidic devices and high-throughput screening for improving the velocity and the number of cells analyzed are also discussed. Finally, the combination of the Raman microscopy (RM) with other imaging modalities, for complete visualization and characterization of the cells, is described.

An experimental and steered molecular dynamics simulation approach to histidine assisted liquid-phase exfoliation of graphite into few-layer graphene.

A simple and green approach to exfoliate graphite in water was developed by its reaction with an amino acid, histidine (His), resulting in the spatial expansion of the interlayer space. Subsequent sonication led to few-layered nanosheets of graphene in water. Steered molecular dynamics (MD) simulations revealed that the exfoliating graphene sheet underwent sheered motion before completely scaling off from the other layer.

Simultaneous Delamination and Rutile Formation on the Surface of Ti3 C2 Tx MXene for Copper Adsorption.

In this work, we studied the formation of the rutile phase of titanium dioxide (TiO2 ) on delaminated MXene (d-Ti3 C2 Tx ) flakes by the reaction of Ti3 C2 Tx with amino acids in water. Three types of amino acids with varied side-chain polarity were used to delaminate Ti3 C2 Tx . d-Ti3 C2 Tx flakes formed stable colloidal solutions due to the negative surface charges of chemisorbed amino acids on the d-Ti3 C2 Tx . Rutile formed on d-Ti3 C2 Tx at room temperature upon the intercalation of aromatic amino acids and subsequent sonication of the solution, while flakes intercalated with aliphatic amino acids did not oxidize. X-Ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy revealed the nanosize rutile formation on the surface of Ti3 C2 Tx flakes. The XPS results indicated the surface functionalization of histidine on d-Ti3 C2 Tx flakes. As-synthesized histidine functionalized rutile TiO2 @d-Ti3 C2 Tx hybrid was used for adsorption of Cu2+ ions from aqueous solution with a maximum uptake of 95 mg g-1 .

A composite film prepared from titanium carbide Ti3C2Tx (MXene) and gold nanoparticles for voltammetric determination of uric acid and folic acid.

In this study, a solution-processing based galvanic deposition approach is described for in-situ deposition of gold nanoparticles (AuNP) on delaminated titanium Ti3C2Tx nanosheets under ultrasonication. The nanocomposite (AuNP@Ti3C2Tx) was placed on a glassy carbon electrode (GCE) and then applied to electrochemically with label-free, and simultaneously sense uric acid (UA), and folic acid (FA) at physiological pH. The modified GCE has attractive figures of merit: (i) The working potentials for UA and AA are well separated (+0.35 V and 0.70 V vs. Ag|AgCl); (ii) wide linear responses (from 0.03-1520 µM for UA and from 0.02-3580 µM for FA; (iii) good electrochemical sensitivities for both UA and FA (0.53 and 0.494 µAµM-1.cm-2, respectively), and (iv) detection limits of 11.5 nM (UA) and 6.20 nM (FA). The electrode exhibited good repeatability (RSD = 4.4%), acceptable reproducibility (RSD = 4.1%), and excellent stability (91.8% over one-month storage). The method was applied to analyze spiked serum samples, and modified GCE is shown appreciable recoveries (97.1-98.8% and 96.8-98.0% for UA, and FA, respectively). Graphical abstractA photograph (top left) of colloidal suspension of gold nanoparticles (AuNPs). They were grown on the delaminated titanium carbide Ti3C2Tx MXene nanosheet via galvanic displacement deposition method, and their corresponding a low-resolution transmission electron microscopy micrograph (top right) of AuNP@Ti3C2Tx. The graphical representation of AuNP@Ti3C2Tx drop-casted on glassy carbon electrode (GCE) (bottom left), and their voltammetric measurement were applied in the presence of both uric acid and folic acid with increasing the concentration of both analytes (bottom right).