ABSTRACT
Fluorescent carbon based-nanoparticles are one of the emerging nanomaterials. Their preparation is relatively simple, rapid and inexpensive, and they are less toxic compared with metal and semiconductor nanoparticles. Here, we report a simple and reliable method to prepare water-soluble fluorescent carbon nanoparticles (FC-NPs) from nanoparticles made from a protein, bovine serum albumin. The obtained mean size of our carbon nanoparticles is between 3.8 and 3.4â¯nm, and they exhibit its maximum fluorescence emission at 424 and 408â¯nm respectively (with a reasonable QY of 16.5%) due to the presence of functional groups (NH, NH2, COOH and OH) that contain O and N; the presence of these functional groups was confirmed by FTIR and XPS analysis. The photoluminescent decay lifetime was modeled by a two exponential fit which indicates a contribution from both core and surface states. Also, the preliminary results showed that FC-NPs had a good interaction with HeLa and normal oral epithelial cells; nanoparticles were permeable at the cell membrane and went to the cytosol, and even to the nucleus, in less than 30â¯min, the fluorescence images of our preliminary results did not show any apparent toxic damage in any of the cell lines.
Subject(s)
Carbon/chemistry , Fluorescent Dyes/chemistry , Nanoparticles/chemistry , Serum Albumin, Bovine/chemistry , Amines/chemistry , Animals , Carboxylic Acids/chemistry , Cattle , Cell Membrane Permeability , Epithelial Cells , HeLa Cells , Humans , Hydrophobic and Hydrophilic Interactions , Optical Imaging , Spectrometry, Fluorescence , Surface PropertiesABSTRACT
In this work, gold nanospheres functionalized with low weight organic molecules (4-aminothiphenol and cysteamine) were synthesized in a one-step method for their in vitro cytotoxic evaluation on HeLa cells. To enhance the biocompatibility of the cysteamine-capped GNPs, BSA was used due to its broad PH stability and high binding affinity to gold nanoparticles. Besides, the widely reported silica coated gold nanorods were tested here to contrast their toxic response against our nanoparticles coated with organic molecules. Our results shown, the viability measured at 1.9×10-5M did not show significant differences against negative controls for all the samples; however, the metabolic activity of HeLa cells dropped when they were exposed to silica gold nanorods in the range of concentrations from 2.9×10-7M to 3.0×10-4M, while in the cases of gold nanospheres, we found that only at concentrations below 1.9×10-5M metabolic activity was normal. Our preliminary results did not indicate any perceivable harmful toxicity to cell membrane, cytoskeleton or nucleus due to our nanospheres at 1.9×10-5M. Additional test should be conducted in order to ensure a safe use of them for biological applications, and to determine the extent of possible damage.
Subject(s)
Gold/toxicity , Metal Nanoparticles/toxicity , Aniline Compounds/chemistry , Cell Survival/drug effects , Cysteamine/chemistry , Cytoskeleton/drug effects , Gold/chemistry , HeLa Cells , Humans , Metal Nanoparticles/chemistry , Nanotubes/chemistry , Nanotubes/toxicity , Serum Albumin, Bovine/chemistry , Silicon Dioxide/chemistry , Sulfhydryl Compounds/chemistryABSTRACT
Serum samples were studied using Raman spectroscopy and analyzed through the multivariate statistical methods of principal component analysis (PCA) and linear discriminant analysis (LDA). The blood samples were obtained from 11 patients who were clinically diagnosed with breast cancer and 12 healthy volunteer controls. The PCA allowed us to define the wavelength differences between the spectral bands of the control and patient groups. However, since the differences in the involved molecules were in their tertiary or quaternary structure, it was not possible to determine what molecule caused the observed differences in the spectra. The ratio of the corresponding band intensities were analyzed by calculating the p values and it was found that only seven of these band ratios were significant and corresponded to proteins, phospholipids, and polysaccharides. These specific bands might be helpful during screening for breast cancer using Raman Spectroscopy of serum samples. It is also shown that serum samples from patients with breast cancer and from the control group can be discriminated when the LDA is applied to their Raman spectra.
Subject(s)
Breast Neoplasms/blood , Spectrum Analysis, Raman , Adult , Breast Neoplasms/diagnosis , Breast Neoplasms/pathology , Case-Control Studies , Female , Humans , Linear Models , Middle Aged , Multivariate Analysis , Pilot Projects , Principal Component AnalysisABSTRACT
Based on the UV-vis absorption spectra of commercially bottled tequilas, and with the aid of multivariate analysis, it is proved that different brands of white tequila can be identified from such spectra, and that 100% agave and mixed tequilas can be discriminated as well. Our study was done with 60 tequilas, 58 of them purchased at liquor stores in various Mexican cities, and two directly acquired from a distillery. All the tequilas were of the "white" type, that is, no aged spirits were considered. For the purposes of discrimination and quality control of tequilas, the spectroscopic method that we present here offers an attractive alternative to the traditional methods, like gas chromatography, which is expensive and time-consuming.
