Generating luminescent Graphene quantum Dots from Tryptophan: Fluorosensors for hydrogen peroxide in cancer cells.

Herein, we report a single step synthesis of highly fluorescent Graphene Quantum Dots (GQDs) using tryptophan and glycerol as precursors via pyrolysis. The morphological and functional characterization of the prepared GQDs was performed using PXRD, FTIR, TEM, XPS and zeta potential measurements. The prepared GQDs found their practical application in ultrasensitive detection of an emerging potential cancer biomarker, H2O2, by exploiting the fluorescence quenching behaviour of H2O2. To evaluate the detection sensitivity, a series of various concentrations of H2O2 was spiked to biomatrices like, serum and MCF-7 (human breast cancer cell line) cell lysate medium. A remarkably low limit of detection (LOD) was found in serum medium (139.5 pM) which further improved in MCF-7 cell lysate medium (LOD 61.43 pM). Moreover, the sensing capacity of the GQDs was further validated in presence of various physiological variables such as glucose, cholesterol, insulin and nitrite. Sensing assay was also carried out in HaCaT (human keratinocyte cell line) cell lysate medium to compare the performance of our prepared sensor but the non-linearity of the F0/F versus H2O2 concentration plot pointed towards the conduciveness of the MCF-7 cell lysate medium for sensitive detection of H2O2.The mechanism behind the sensing was also explored using spectroscopic methods.

A multispectroscopic approach for ultra-trace sensing of prostate specific antigen (PSA) by iron nanocomposite fabricated on graphene nanoplatelet.

Herein we report an easy, rapid and cost-effective method for spectroscopic sensing of a prostate cancer biomarker prostate specific antigen (PSA) using a novel nanocomposite. The material is a synthetic quinoxaline derivative-based iron nanocomposite fabricated on graphene nanoplatelet surface (1d-Fe-Gr). Presence of graphene enhanced the efficacy of synthesized 1d-Fe-Gr to sense PSA in serum medium with an impressive limit of detection (LOD) value of 0.878 pg/mL compared to 1d-Fe alone (LOD 17.619 pg/mL) using UV-visible absorption spectroscopy. LOD of PSA by 1d-Fe-Gr using Raman spectroscopy is even more impressive (0.410 pg/mL). Moreover, presence of interfering biomolecules like glucose, cholesterol, bilirubin and insulin in serum improves the detection threshold significantly in presence of 1d-Fe-Gr which otherwise cause LOD values of PSA to elevate in control sets. In presence of these biomolecules, the LOD values improve significantly as compared to healthy conditions in the range 0.623-3.499 pg/mL. Thus, this proposed detection method could also be applied efficiently to the patients suffering from different pathophysiological disorders. These biomolecules may also be added externally during analyses to improve the sensing ability. Fluorescence, Raman and circular dichroism spectroscopy were used to study the underlying mechanism of PSA sensing by 1d-Fe-Gr. Molecular docking studies confirm the selective interaction of 1d-Fe-Gr with PSA over other cancer biomarkers.

Neutron Activation Analysis: An Excellent Nondestructive Analytical Technique for Trace Metal Analysis.

For proper functioning of the human body, several metals are required in different concentrations but if their concentration slightly elevates, because of any metal-contaminated environment or of other food sources, which leads to high toxicity and different chronic health issues. Different analytical techniques like atomic absorption spectroscopy, X-ray fluorescence, inductively coupled plasma- mass spectroscopy (ICP-MS) and flame atomic absorption spectroscopy are used for metals analysis present in different samples in different fields but nowadays neutron activation analysis (NAA) is preferred over other analytical techniques because it is an efficient, multi-elemental, nondestructive analytical technique having an ultralow minimum detection limit, therefore it can detect heavy metals (HMs) even if at a very trace level parts per billion (ppb) with a quite simple sample preparation technique. This technique is known as "referee technique" because of its accuracy and trustworthiness. There is a widespread use of this technique in biomedical science like in Alzheimer's disease, cancer, arthritis, metabolism study, brain tumor and in many more conditions where metals are actively present. For its typical sample sizes and due to a multitude of additional benefits, it also helps in mapping of pathophysiology of the disease. Besides all, mainly in biomedical science the biological samples can easily be analyzed irrespective of any form. In recent years NAA is preferred over other analytical techniques in several research fields, so this article focuses on the analytical technique, its general principle and recent applications.

Heme-Mimetic Potential of Iron Conjugated Pheophytin-I in Attenuating Oxidative Stress-Induced Cellular and Vascular Toxicity.

Purpose of the Study: Heme is the cardinal porphyrin in systemic physiology, apart from hemoglobin it forms structural skeleton of physiological antioxidants such as catalase and peroxidases. Aim: The current study presents evidence that iron chelated pheophytin (Fe-Ph-I) created in resemblance to heme can exert significant heme-mimetic efficacy in mitigating oxidative stress-induced cellular and vascular damage. Materials and Methods: Fe-Ph-I was synthesized by incorporating ferrous ion into the porphyrin core of Ph-I moiety. The candidate drugs (Ph-I and Fe-Ph-I) were characterized by spectroscopic analysis and heme-mimetic attribute of Fe-Ph-I was established by comparing the efficacy of Fe-Ph-I with reference to its unmetallated parent Ph-I as well as un-chelated ferrous ions in a host of in vitro, ex vivo, and in vivo bioassays paradigms. Results: The study confirmed that Fe-Ph-I, Ph-I, and free ferrous ions all exerts significant in vitro anti-radical efficacy, however, while un-chelated ferrous ions intensifies, Ph-I and Fe-Ph-I mitigate ex vivo oxidative stress with Fe-Ph-I exhibiting superior potency. Also from in vivo assessment of oxidative stress-induced hemolytic anemia, it was observed that Fe-Ph-I is significantly superior than Ph-I in alleviating intravascular hemolysis, thereby endorsing that not ferrous ions alone but ferrous ion chelated with porphyrin yielding a heme-mimetic structure is responsible for superior potency of Fe-Ph-I over Ph-I. Conclusion: In conclusion, Fe-Ph-I is cost-effective and therapeutically safe biological macromolecule of clinical potency against pathologies either mediated by or themselves precipitate oxidative stress-induced cellular or vascular damage.

Disparity of selenourea and selenocystine on methaemoglobinemia in non-diabetics and diabetics.

Organoselenium drugs like selenourea (SeU) and selenocystine (SeC) are found to exhibit several medicinal properties and have reported roles in the field of cancer prevention. However, studies related to their interactions with the major erythroid protein, haemoglobin (HbA) are still in dearth despite being of prime importance. In view of this, it was considered essential to investigate the interaction of these two anticancer drugs with Hb. Both the drugs showed significant changes in absorption spectra of Hb at wavelength of maximum absorption (λmax) 630 nm. SeU itself had no effect on the absorbance value at 630 nm with respect to time even with 400 µM concentration. However, it was rapidly converted to nanoselenium in presence of nitrite and there was an increase in the absorbance rate at 630 nm from 3.39 × 10-3 min-1 (without nitrite) to 8.94 × 10-3 min-1 in presence of nitrite (200 µM) owing to the generation of reactive oxygen species in the medium. Although the generation and increase in peak intensity at 630 nm in Hb generally indicates the formation and rise in the levels of methaemoglobin (metHb), nanoselenium was observed to follow a different path. Instead of causing oxidation of Fe2+ to Fe3+ responsible for metHb formation, nanoselenium was found to interact with the protein part, thereby causing changes in its secondary structure which is reflected in the increasing absorbance at 630 nm. SeC, however, showed a different effect. It was shown to act as a novel agent to reduce nitrite-induced metHb formation in a dose-dependent manner. The efficiency of SeC was again found to be less in diabetic blood samples as compared to the non-diabetic ones. For similar ratio of metHb to SeC (1:8), % reduction of metHb was found to be 27.46 ± 0.82 and 16.1 ± 2.4 for non-diabetic and diabetic samples, respectively, with a two tailed P-value much <0.05 which implies that the data are highly significant.

Effect of organo-selenium anticancer drugs on nitrite induced methemoglobinemia: A spectroscopic study.

Selenium containing drugs like selenomethionine, selenocystine, selenourea and methylseleninic acid are reported to exhibit potential anticancer effect. However, these anticancer drugs may exert adverse effects when used over a prolonged period. Little is known about the interaction of these selenium containing drugs with the vital erythroid protein hemoglobin. In this work a comparative study of the interaction of organo-selenium drugs with hemoglobin and heme moiety has been performed using different spectroscopic techniques to find out their role on drug induced methemoglobinemia. We found that though these selenium containing drugs have similar binding affinity towards hemoglobin, they have differential interactions with the heme group. Isothermal calorimetric titration study showed that selenourea has the lowest binding affinity (Kd 19.28 µM) towards HbA as compared to other drugs, selenomethionine, selenocystine and methylseleninic acid (Kd 7.69 µM, 4.88 µM and 10.5 µM at 37 °C respectively). This result is also supported by the molecular docking study. Methylseleninic acid was found to have detrimental effects on nitrite induced methemoglobinemia, a hematological disorder caused due to excessive conversion of Fe2+ to Fe3+ in hemoglobin. Hence the results of the study would help to develop a better insight on the mechanism of action and anticipate the toxicity of these drugs which require further optimization before their actual use in the treatment of cancer.

Nanoemulsion: A Novel Eon in Cancer Chemotherapy.

Cancer refers to an assemblage of lethal diseases characterized by abnormal growth of cells. The most celebrated adverse effects accredited to the cytotoxic class of anticancer agents are constructed owing to their inability to differentiate between the abnormally multiplying cancerous cell mass and the rapidly dividing healthy cells of the human body. Consequently, unknown targets chemotherapy for cancer play host to a multitude of adverse effects ranging from nausea, alopecia to torturous ages associated with the current treatment etiquette. Nano-pharmaceuticals constitute the advanced scale drug targeting technologies. Nanoemulsion is an important tool in the nano-technological arena designed for clinical and therapeutic application. Currently among different nano-carriers, nanoemulsions are extensively envisaged as efficient drug delivery systems for the targeted delivery of lipophilic cytotoxic antineoplastic agents. Beauties of nanoemulsion include optical clarity, biocompatibility, non-immunogenic, biodegradable, drug encapsulation, sustained and controlled release, nanometric size, large surface area, ease of preparation and thermodynamic stability. After excessive delving, the research fraternity has acknowledged nanoemulsions as proficient nanocarriers capable of effectively addressing the low bioavailability and noncompliance issues associated with the conventional anticancerous chemotherapeutic dosage forms. This review attempts to shed new light on the current status of nanoemulsion in the cancer therapeutics, and commercial field on the basis of morphology, formulation, characteristics and characterization parameters.

Peanut protein sensitivity towards trace iron: a novel mode to ebb allergic response.

Peanut is a rich source of plant protein which is inexpensive and abundant in nature. The peanut proteins however cause hypersensitive immunogenic responses in certain individuals. A minute amount of contamination may cause strong allergic reactions and even death. Many chemical pretreatment procedures have been developed and prescribed earlier for removal of this allergenicity. In the present article we have observed trace level Fe(III) and Cu(II) complexation of the protein fractions of peanut at pH 4.8 using different spectral methods. Consequently we studied the allergic response of Fe(III) complex of the protein fractions using competitive enzyme linked immunosorbent assay (ELISA) technique and found that there were considerable losses in allergenicity of conarachin I and arachin fractions upon complexation. Immunoassay of Cu(II) complex was avoided keeping in view the Cu toxicity in living systems. The results bring up a new strategy towards reduction of allergenicity using an inexpensive and simple methodology.