Radiation resistance is one of the major causes of recurrence and failure of radiotherapy. Different methods have been used to increase the efficacy of radiation therapy and at the same time restrict the radiation resistivity. From last few years nanoparticles have played a key role in the enhancement of radiosensitization. The densely packed nanoparticles can selectively scatter or absorb the high radiations, which allow better targeting of cellular components within the tumor hence resulting in increased radiation damage to the cancer cells. Glioblastoma multiforme (GBM) is one of the highly radioresistant brain cancer. Current treatment methods are surgical resection followed by concurrent chemo and radiation therapy. In this study we have used in-house engineered gold nano rodes (GNR) and analyzed their effect on U-87MG cell lines. MTT assay was employed to determine the cytotoxic concentration of the nanoparticles. Raman spectroscopy was used to analyze the effect of gold nanoparticles on glioma cells, which was followed by transmission electron microscopic examinations to visualize their cellular penetration. Our data shows that GNR were able to penetrate the cells and induce cytotoxicity at the concentration of 198 μM as determined by MTT assay at 24 post GNP treatment. Additionally, we show that Raman spectroscopy, could classify spectra between untreated and cells treated with nanoparticles. Taken together, this study shows GNR penetration and cytotoxicity in glioma cells thereby providing a rationale to use them in cancer therapeutics. Future studies will be carried out to study the biological activity of the formulation as a radiosensitizer in GBM.
Single cell analysis can provide important information regarding cell composition, and can be used for biomedical applications. In this work, a SERS active substrate formed by 3 layers of gold nanospheres and a final layer of gold nanocubes was used for the label-free SERS analysis of HeLa cells. Nanocubes were selected due to the high electromagnetic enhancement expected in nanoparticles with sharp corners. Significant improvement in the reproducibility and quality of SERS spectra was found when compared to the spectra obtained using a nanosphere-only substrate and normal Raman spectroscopy.
Optical Coherence Tomography (OCT) is an imaging technique to get cross-sectional images with resolutions of a few
microns and deep penetration in tissue of some millimeters. For many years OCT has been applied to analyze different
human tissues like eyes, skin, teeth, urinary bladders, gastrointestinal, respiratory or genitourinary tracts and recently
breast cancer tissues have been studied. Many of these tissues are composed specially of lipids and collagen, proteins
which cause multiple light scattering (MLS) reducing significantly the optical depth and the contrast of OCT imaging. So,
one of the big challenges of this technique is to acquire images with good contrast. Gold nanoparticles (NPs) exhibit
interesting optical properties due to its plasmon resonance frequency. Optical absorbance is strong when gold NPs have
dimension under 50 nm, but over this size optical scattering becomes dominant. In this work we show the preliminary
results of the use of gold NPs as a contrast medium to enhance the OCT images quality. Our experimental results show
which type of particles (morphology and size) present the best enhancement in the region of 1325 nm which corresponds
to the central wavelength source excitation. All our experiments were carried out with a commercial OCT (thorlabs)
system and our NPs were tested in water and gel phantoms.
Metal nanometer-size particles show intriguing optical properties which depend on their shape, size and local
environment. For these reasons, these materials have received a lot of attention in different scientific areas, and several
applications can be found, for example: fabrication of bio-sensor, electronic devices, catalysis and new drugs. However,
in the case of biomedical applications, metallic nanoparticles need to satisfy several requirements: bio-compatibility,
stability and functionality. To satisfy these requirements, metallic nanoparticles need to be modified in their surfaces. In
this work we report the synthesis and the modification of gold nanoparticles (GNPs) surface. GNPs were fabricated
following the Turkevich's method, and the bio-conjugation (surface modification) was done using cysteine and bovine
serum albumin (BSA). Our results of Uv-vis spectroscopy show that BSA and cysteine permit to increase the stability of
GNPs in presence of NaCl, the stability is function of BSA concentration. Also to verify the bio-conjugation we used
Raman spectroscopy and gel electrophoresis.
In this work, fast and reliable spectroscopic methods in combination with chemometric tools were developed for
simultaneous determination of Acetylsalicylic Acid, Acetaminophen and Caffeine in commercial formulations. For the
first-order multivariate calibration method (PLS-1), calibration and validation sets were constructed with 23 and 10
samples respectively according to a central composite design. The Micro-Raman, FTIR-HATR and UV absorption
spectra in the region of 100-2000 cm-1, 400-4400 cm-1 and 200-350 nm, respectively, were recorded. The % REP's
(Percentage of relative error of prediction) was less than 18 for all used spectroscopic techniques. Subsequently,
commercial pharmaceutical samples were analyzed with percentage of recovery between 90 and 117% for the three
compounds.
Raman spectroscopy and Multivariate methods were used to study serum blood samples of control and breast cancer
patients. Blood samples were obtained from 11 patients and 12 controls from the central region of Mexico. Our results
show that principal component analysis is able to discriminate serum sample of breast cancer patients from those of
control group, also the loading vectors of PCA plotted as a function of Raman shift shown which bands permitted to
make the maximum discrimination between both groups of samples.
Clinical diagnosis of infections, generally are realized by serological methods, which identifies the antibodies presents
in serum or tissue fluids of the patient. Antibodies are proteins present in our bodies that aid in the elimination of
pathogens or antigens. Identification of antibodies isotypes is important because can help to predict when and whether
patients will recover from infections and are commonly diagnosed by means of indirect methods such as serological test. In the other hand, the majority of these methods requires specific kits for the analysis, special sample preparation, chemical reagents, expensive equipment and require long time for getting results. In this work we show the feasibility to discriminate antibody isotypes in biological fluids like human colostrum by means of Raman spectroscopy and chemometrics. Spectra were obtained using an excitation wavelength of 514 nm over dried samples of human colostrum labeled previously as positives to specific IgG and IgM antibodies against Toxoplasma Gondii by means of ELISA test. Partial least square-discriminant analysis (PLS-DA) was used to discriminate among antibody isotypes by use second derivative of Raman spectra of colostrum samples.
An alternative method to chromatography is reported to discriminate among white and aging tequilas. In a previous
work we had reported a similar method to discriminate between 100% blue agave and mixed tequilas. A data base of
145 tequilas was created where well known tequila brands and tequilas in bulk were included. The bottled tequilas were
purchased at various Mexican liquor stores to ensure that different batches of each brand were included in the data base.
The method that we propose to discriminate tequilas may also be used for quality control in distilleries and, with the
help of the data base, to identify counterfeit tequilas.
More than 60 million people in the United States and 23 million people in Mexico probably are infected with the Toxoplasma parasite, but very few have symptoms because the immune system usually keeps the parasite from causing illness. However, for people whose immune system is compromised, the consequences can be fatal. Toxoplasmosis is detected indirectly by different serological tests, where the sample requires a previous preparation. We analyze the feasibility to use Raman spectroscopy and principal component analysis (PCA) as an alternative method to detect the presence or absence of antibodies IgG (immunoglobulin G), IgM (immunoglobulin M), and IgA (immunoglobulin A), against Toxoplasma gondii, in a simple and fast way, in samples of human colostrum from a group of volunteers who were in contact with the parasite and others who were not in contact with the parasite.
A brief review of the state of the art in quantitative photoacoustic spectroscopy for thermally thick samples is presented. We demonstrate that it is possible to find an analytical expression that allows studying the optical absorption coefficient by combining the amplitude and phase of the photoacoustic signal, obtained from the heat diffusion model, for thermally thick samples.
A low cost technique based on the UV-VIS absorption spectroscopy is presented for the quality control of the spirit drink known as tequila. It is shown that such spectra offer enough information to discriminate a given spirit drink from a group of bottled commercial tequilas. The technique was applied to white tequilas. Contrary to the reference analytic methods, such as chromatography, for this technique neither special personal training nor sophisticated instrumentations is required. By using hand-held instrumentation this technique can be applied in situ during the production process.
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