Label-free detection and mapping of graphene oxide in single HeLa cells based on MCR-Raman spectroscopy.

GO is a 2D nanomaterial that has attracted attention in many industries in recent years, such as the chemical industry, electronics or medicine. Due to its unique properties such as strength, hydrophilicity and large specific surface area with the possibility of functionalization, GO is a particularly attractive material in biomedicine as a candidate for use in targeted drug delivery. In such a case, we need information on whether graphene oxide penetrates into cells and whether we are able to detect and monitor GO in these cells during and also after the treatment to evaluate possible degradation process of GO and its interaction within the cell compartements. This work introduces the Raman spectroscopy as label-free detection method showing the advantages of combining Raman spectroscopy with MCR (Multivariate Curve Resolution) analysis for advanced detection of GO in cervical cancer (HeLa) cells. Our synthesized GO is characterized firstly by AFM, SEM and Raman spectroscopy and then MCR-Raman spectroscopy is used to detect internalized GO in individual HeLa cells. Moreover, by using our methodology, distribution of GO as well as its chemical stability inside the cell for up to six months is investigated without using any additional labeling or tracing the GO. Thus, MCR-Raman spectroscopy may become a new analytical tool in preclinical and clinical applications of graphene-based nanotheranostics.

Perspectives of DCDR-GERS in the analysis of amino acids.

Graphene-enhanced Raman scattering (GERS) has attracted increasing attention from many scientists in recent years as a novel and potentially strong analytical technique since its discovery in 2010. GERS combines the ultra-high sensitivity and spectral analysis of the structural properties of many molecules found in surface-enhanced Raman scattering (SERS) and graphene simple sample processing and excellent uniformity. This facilitates a fast and very sensitive analysis of a wide range of analytes. Here, we present a new method for amino acid analysis based on the combination of drop coating deposition Raman (DCDR) and GERS. The potential of the method was evaluated in the analyses of Trp, Leu, Phe, and DOPA. Achievable limits of detection for all the studied amino acids are in tens of ng mL-1.

Chiral discrimination of amino acids using phosphorene assisted graphene-enhanced Raman spectroscopy.

Discrimination of enantiomers poses a scientific challenge as the chemical and physical properties of enantiomers are nearly identical. The chiral analysis is usually performed by separation techniques, including chromatography, electrophoresis, or optical instrumentation based on an interaction of the analyzed sample with a polarized beam of light. Here we present a novel method for a chiral screening based on a combination of the black phosphorus@Graphene nanocomposite and Raman spectroscopy. The nanocomposite allows to enhance the Raman signal with factors higher than 100 asymmetrically and provide altered signals for mixtures containing varying enantiomeric ratios of target compounds. Tryptophan, Phenylalanine, DOPA, Isoleucine, and Leucine were selected as model compounds; the method allows us to discriminate between mixtures with 10, 25, 50, 75, and 100% enantiomeric purity.

Imaging of growth factors on a human tooth root canal by surface-enhanced Raman spectroscopy.

Endodontic treatment of immature permanent teeth with necrotic pulp poses several clinical challenges and is one of the most demanding interventions in endodontics. Recently, with new discoveries in the field of tissue engineering, novel treatment protocols have been established. The most promising treatment modality is revascularization, whose integral part is the exposure of collagen matrix and embedded growth factors. However, optimization of the treatment protocol requires a development of analytical procedures able to analyze growth factors directly on the sample surface. In this work, method based on surface-enhanced Raman spectroscopy (SERS) was developed to investigate the influence of the time of the medical treatment using EDTA on exposure and accessibility of the growth factors, namely TGF-ß1, BMP-2, and bFGF on the dentine surface. The nanotags, which consist of magnetic Fe3O4@Ag nanocomposite covalently functionalized by tagged antibodies (anti-TGF-ß1-Cy3, anti-BMP-2-Cy5, and anti-bFGF-Cy7), were employed as a SERS substrate. Each antibody was coupled with a unique label allowing us to perform a parallel analysis of all three growth factors within one analytical run. Developed methodology presents an interesting alternative to a fluorescence microscopy and in contrary allows evaluating a chemical composition and thus minimizing possible false-positive results. Graphical abstract.

Label-free determination of prostate specific membrane antigen in human whole blood at nanomolar levels by magnetically assisted surface enhanced Raman spectroscopy.

Prostate cancer is one of the most common cancers among men and can in its later stages cause serious medical problems. Due to the limited suitability of current diagnostic biochemical markers, new biomarkers for the detection of prostate cancer are highly sought after. An ideal biomarker should serve as a reliable prognostic marker, be applicable for early diagnosis, and be applicable for monitoring of therapeutic response. One potential candidate is glutamate carboxypeptidase II (GCPII), also known as prostate specific membrane antigen (PSMA), which has a promising role for direct imaging. GCPII is considerably over-expressed on cancerous prostatic epithelial cells; its analysis typically follows radiological or spectrophotometric principles. Its role as a biomarker present in blood has been recently investigated and potential correlation between a concentration of GCPII and prostate cancer has been proposed. The wider inclusion of GCPII detection in clinical praxis limits mainly the time and cost per analysis. Here, we present a novel analytical nanosensor applicable to quantification of GCPII in human whole blood consisted of Fe3O4@Ag magnetic nanocomposite surface-functionalized by an artificial antibody (low-molecular-weight GCPII synthetic inhibitor). The nanocomposite allows a simple magnetic isolation of GCPII using external magnetic force and its consecutive determination by magnetically assisted surface enhanced Raman spectroscopy (MA-SERS) with a limit of detection 6 pmol. L-1. This method enables a rapid determination of picomolar concentrations of GCPII in whole human blood of healthy individuals using a standard addition method without a complicated sample pre-treatment.

Staphylococcal scalded skin syndrome in the Czech Republic: an epidemiological study.

OBJECTIVE: To identify the basic epidemiological characteristics of children hospitalized with diagnosis of Staphylococcal scalded skin syndrome in the Czech Republic in the years 1994-2009. INTRODUCTION: Staphylococcal scalded skin syndrome (SSSS) is a relatively rare disease in childhood. This syndrome was first defined in 1878 by Baron Gottfried Ritter von Rittershainem and belongs to the group of diseases called Burn-like syndromes. It is a bullous skin disease caused by exfoliative toxins which are produced by certain types of Staphyloccocus aureus. Typical structures affected by these toxins are desmosome proteins called Desmoglein-1 located in the stratum granulosum of epidermis. Unlike in Lyell's syndrome or Stevens-Johnson's syndrome, the exfoliation is caused by loss of adhesivity particularly in the stratum granulosum and not by induction of apoptosis in the dermo-epidermal junction. MATERIAL AND METHODS: This retrospective study was conducted on patients hospitalized in the Czech Republic in the period from 1.1.1994 to 31.12.2009. The basic condition for the inclusion in the retrospective study was age under 1 year and hospitalization due to SSSS. A total of 399 children (177 girls) fulfilled the criteria for inclusion into the study. Information was obtained from a central data depository, the Department of Health Information and Statistics, Czech Republic. RESULTS: A total of 399 children under 1 year were hospitalized for the diagnosis of SSSS in the study period. The group included 177 girls and 222 boys. M:F ratio was 1.25:1. The average incidence of SSSS in the Czech Republic was 25.11 cases per 100,000 children under 1 year of age. The highest recorded incidence in the followed period was in 1994, when a total of 57 cases of SSSS was reported, namely 53.47 per 100,000 children. By contrast, in 2003, there were reported only 12 cases and the incidence of 12.81 per 100,000 children. The average length of hospitalization was 6.39 days. In 1995, the highest average length of hospitalization was reported, which was 8.1 days, and then in 2007, the lowest average length of hospitalization, 4.4 days. There was no significant difference in the length of hospitalization in boys and girls. None of the 399 children in the population died. CONCLUSION: In our retrospective study, we established basic epidemiological characteristics of a group of children aged under 1 year with diagnosis of SSSS. As epidemiological data show, the occurrence of this syndrome is not sporadic, but steady.