Functionalized Multilayered Graphene Platform for Urea Sensor

Srivastava, Rajesh K.,Srivastava, Saurabh,Narayanan, Tharangattu N.,Mahlotra, Bansi D.,Vajtai, Robert,Ajayan, Pulickel M.,Srivastava, Anchal American Chemical Society 2012 ACS NANO Vol.6 No.1

<P>Multilayered graphene (MLG) is an interesting material for electrochemical sensing and biosensing because of its very large 2D electrical conductivity and large surface area. We propose a less toxic, reproducible, and easy method for producing functionalized multilayer graphene from multiwalled carbon nanotubes (MWCNTs) in mass scale using only concentrated H<SUB>2</SUB>SO<SUB>4</SUB>/HNO<SUB>3</SUB>. Electron microscopy results show the MLG formation, whereas FTIR and XPS data suggest its carboxylic and hydroxyl-functionalized nature. We utilize this functionalized MLG for the fabrication of a novel amperometric urea biosensor. This biosensor shows linearity of 10–100 mg dL<SUP>–1</SUP>, sensitivity of 5.43 μA mg<SUP>–1</SUP> dL cm<SUP>–2</SUP>, lower detection limit of 3.9 mg dL<SUP>–1</SUP>, and response time of 10 s. Our results suggest that MLG is a promising material for electrochemical biosensing applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2012/ancac3.2012.6.issue-1/nn203210s/production/images/medium/nn-2011-03210s_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn203210s'>ACS Electronic Supporting Info</A></P>

Reduced graphene oxide modified smart conducting paper for cancer biosensor

Kumar, Saurabh,Kumar, Suveen,Srivastava, Saurabh,Yadav, Birendra K.,Lee, Seung H.,Sharma, Jai G.,Doval, Dinesh C.,Malhotra, Bansi D. Elsevier 2015 Biosensors & bioelectronics Vol.73 No.-

<P><B>Abstract</B></P> <P>We report results of the studies relating to the fabrication of a paper based sensor comprising of poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and reduced graphene oxide (RGO) composite. The effect of various solvents like methanol, ethylene glycol and H<SUB>2</SUB>SO<SUB>4</SUB> on the electrical conductivity of PEDOT:PSS coated Whatman paper has been investigated. The conductivity of this solution processed conducting paper significantly increases from ~1.16×10<SUP>−4</SUP> Scm<SUP>−1</SUP> up to ~3.57×10<SUP>−2</SUP> Scm<SUP>−1</SUP> (~300 times) on treatment with ethylene glycol. The observed significant increase in electrical conductivity is due to conformational rearrangement in the polymer and is due to strong non-covalent cooperative interaction between PEDOT and the cellulose molecules. Further, incorporation of RGO into the conducting paper results in improved electrochemical performance and signal stability. This paper electrode is a promising alternative over the expensive conventional electrodes (ITO, gold and glassy carbon), that are known to have limited application in smart point-of-care (POC) devices. This low cost, flexible and environment friendly conducting paper based biosensor utilized for cancer biomarker (carcinoembryonic antigen, CEA) detection reveals high sensitivity of 25.8µAng<SUP>−1</SUP> mLcm<SUP>−2</SUP> in the physiological range, 1–10ngmL<SUP>−1</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Solution processed reduced graphene oxide modified conducting paper sensor is reported for cancer detection. </LI> <LI> This paper sensor is exceptionally low cost, flexible and disposable. </LI> <LI> It exhibits high sensitivity of 25.8µAng<SUP>−1</SUP> mLcm<SUP>−2</SUP> in the detection range of 1–10ngmL<SUP>−1</SUP> for cancer biomarker (carcinoembryonic antigen, CEA) detection. </LI> <LI> This conducting paper electrode is a promising alternative over the expensive conventional electrodes (ITO, gold and glassy carbon) for application to POC devices. </LI> </UL> </P>

Breakthrough modeling of furfural sorption behavior in a bagasse fly ash packed bed

Saurabh Singh,Vimal Chandra Srivastava,Akash Goyal,Indra Deo Mall 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.1

Adsorptive breakthrough modelling is essential for design of a sorption packed bed. In this work, breakthrough modelling of the furfural uptake in bagasse fly ash (BFA) packed bed has been performed. Effect of various parameters like bed height (Z = 15-60 cm), flow rate (Q = 0.02-0.04 L/min) and initial furfural concentration (C₀ = 50-200 mg/L) on the breakthrough curve of furfural sorption in a BFA packed bed have been studied. Enhanced breakthrough performance was observed for the higher value of Z, and lower values of C₀ and Q. For C₀ = 100 mg/L, packed bed operated at Q = 0.03 L/min and Z = 60 cm was found to have lowest adsorbent utilization rate of 5.61 g/L with highest breakthrough volume of 14.67 L. Bed depth service time and Thomas models well represented the experimental data points under all experimental conditions. It can be concluded that BFA can be utilized efficiently in continuous system for the removal of furfural. Overall, more than 99% of furfural was adsorbed in BFA packed bed at experimental conditions.

Effect of NTT on Performance of AODV in a Grid Topology-Based Wireless Ad Hoc Network

Saurabh Sharma,Alok Singh,Rajneesh Kumar Srivastava 한국정보과학회 2022 Journal of Computing Science and Engineering Vol.16 No.3

Routing in wireless ad hoc networks that enable nodes, acting as routers also, to find the best path between source and destination nodes, taking into account cost, is a very challenging task. In the present work, an investigation of performance of AODV routing protocol in a grid topology based ad hoc network by varying the value of node traversal time (NTT) and taking into account absence and presence of Hello messages is reported. A set of metrics, including Average End-to-End Delay, Packet Delivery Ratio, Throughput, Routing Overhead, Route Error Overhead, Normalized Routing Load, Average Hop Count, and Total Number of Received Data Packets, has been used to assess the performance of AODV in the grid network. Performance of AODV routing protocol varies in the value of NTT. Throughput in grid topology, by and large, is observed to decrease with an increase in NTT. However, explicit relations between certain metrics with NTT as well as simulation time could not be traced due to intricacies involved in the combination of states of various links and flows in the grid topology. To have better insights, grid topologies of two, three, and four rows are planned to be investigated in the future.

Non-invasive Methods for Determination of Cellular Growth in Podophyllum hexandrum Suspension Cultures

Chattopadhyay, Saurabh,Bisaria, V.S.,Scheper, T.,Srivastava, A.K. The Korean Society for Biotechnology and Bioengine 2002 Biotechnology and Bioprocess Engineering Vol.7 No.6

Culture conductivity and on-line NADH fluorescence were used to measure cellular growth in plant cell suspension cultures of Podophyllum hexandrum. An inverse correlation between dry cell weight and medium conductivity was observed during shake flask cultivation. A linear relationship between dry cell weight and culture NADH fluorescence was obtained during the exponential phase of batch cultivation In a bioreactor under the pH stat (pH 6) conditions. It was observed that conductivity measurement were suitable for biomass characterisation under highly dynamic uncontrolled shake flask cultivation conditions. However, if the acid/alkali feeding is done for pH control the conductivity measurement could not be applied. On the other hand the NADH fluorescence measurement allowed online-in situ biomass monitoring of rather heterogenous plant cell suspension cultures in bioreactor even under the most desirable pH stat conditions.

Bioprocess Considerations for Production of Secondary Metabolites by Plant Cell Suspension Cultures

Chattopadhyay, Saurabh,Farkya, Sunita,Srivastava, Ashok K.,Bisaria, Virendra The Korean Society for Biotechnology and Bioengine 2002 Biotechnology and Bioprocess Engineering Vol.7 No.3

Plant cell culture provides a viable alternative over whole plant cultivation for the production of secondary metabolites. In order to successfully cultivate the plant cells at large scale, several engineering parameters such as, cell aggregation, mixing, aeration, and shear sensitivity are taken into account for selection of a suitable bioreactor. The media ingredients, their concentrations and the environmental factors are optimized for maximal synthesis of a desired metabolite. Increased productivity in a bioreactor can be achieved by selection of a proper cultivation strategy (batch, fed-batch, two-stage etc.), feeding of metabolic precursors and extraction of intracellular metabolites. Proper understanding and rigorous analysis of these parameters would pave the way towards the successful commercialization of plant cell bioprocesses.

Non-invasive Methods for Determination of Cellular Growth in Podophyllum hexandrum Suspension Cultures

A. K. Srivastava,Saurabh Chattopadhyay,V. S. Bisaria,T. Scheper 한국생물공학회 2002 Biotechnology and Bioprocess Engineering Vol.7 No.6

Culture conductivity and on-line NADH fluorescence were used to measure celulargrowth in plant cel suspension cultures of Podophyllum hexandrum. An inverse corelation between dry cel weight and medium conductivity was observed during shake flask cultivation. A linear relationship between dry cel weight and culture NADH fluorescence was obtained during the exponential phase of batch cultivation in a bioreactor under the pH stat (pH 6) conditions. It was observed that conductivity measurement were suitable for biomass characterisation under highly done for pH control the conductivity measurement could not be applied. On the other hand the NADH fluorescence measurement allowed online-in situ biomass monitoring of rather heterogenous plant cel suspension cultures in bioreactor even under the most desirable pH stat conditions.

Expression Levels of Tetraspanin KAI1/CD82 in Breast Cancers in North Indian Females

Singh, Richa,Bhatt, Madan Lal Brahma,Singh, Saurabh Pratap,Kumar, Vijay,Goel, Madhu Mati,Mishra, Durga Prasad,Srivastava, Kirti,Kumar, Rajendra Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.7

Background: Carcinogenesis is a multifaceted intricate cellular mechanism of transformation of the normal functions of a cell into neoplastic alterations. Metastasis may result in failure of conventional treatment and death Hence, research on metastatic suppressors in cancer is a high priority. The metastatic suppressor gene CD82, also known as KAI1, is a member of the transmembrane 4 superfamily which was first identified in carcinoma of prostate. Little work has been done on this gene in breast cancer. Herein, we aimed to determine the gene and protein level expression of CD82/KAI1 in breast cancer and its role as a prognosticator. Materials and Methods: In this study, 83 histologically proven cases of breast cancer and a similar number of controls were included. Patient age ranged from 18-70 years. Quantitative Real Time Polymerase Chain Reaction (q-RT PCR) and immunohistochemistry (IHC) were used to investigate KAI1 expression at gene and protein levels, respectively. Statistical analysis was done to correlate expression of KAI1 and clinicopathological parameters. Results: It was revealed that: (i) KAI1 was remarkably diminished in metastatic vs non metastatic breast cancer both at the gene and the protein levels (P < .05); (ii) KAI1 expression levels were strongly correlated with TNM staging, histological grade and advanced stage (p<0.001) and no association was found with any other studied parameter; (iii) Lastly, a significant correlation was observed between expression of KAI1 and overall median survival of BC patients (P = 0.04). Conclusions: Our results suggest that lack of expression of the KAI1 might indicate a more aggressive form of breast cancer. Loss of KAI1 may be considered a significant prognostic marker in predicting metastatic manifestation. When evaluated along with the clinical and pathological factors, KAI1 expression may be beneficial to tailor aggressive therapeutic strategies for such patients.

Parameters Involved in Autophosphorylation in Chronic Myeloid Leukemia: a Systems Biology Approach

Kumar, Himansu,Tichkule, Swapnil,Raj, Utkarsh,Gupta, Saurabh,Srivastava, Swati,Varadwaj, Pritish Kumar Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.13

Background: Chronic myeloid leukemia (CML) is a stem cell disorder characterized by the fusion of two oncogenes namely BCR and ABL with their aberrant expression. Autophosphorylation of BCR-ABL oncogenes results in proliferation of CML. The study deals with estimation of rate constant involved in each step of the cellular autophosphorylation process, which are consequently playing important roles in the proliferation of cancerous cells. Materials and Methods: A mathematical model was proposed for autophosphorylation of BCR-ABL oncogenes utilizing ordinary differential equations to enumerate the rate of change of each responsible system component. The major difficulty to model this process is the lack of experimental data, which are needed to estimate unknown model parameters. Initial concentration data of each substrate and product for BCR-ABL systems were collected from the reported literature. All parameters were optimized through time interval simulation using the fminsearch algorithm. Results: The rate of change versus time was estimated to indicate the role of each state variable that are crucial for the systems. The time wise change in concentration of substrate shows the convergence of each parameter in autophosphorylation process. Conclusions: The role of each constituent parameter and their relative time dependent variations in autophosphorylation process could be inferred.

CRISPR/Cas9 assisted stem cell therapy in Parkinson's disease

Poojitha Pinjala,Kamatham Pushpa Tryphena,Renuka Prasad,Dharmendra Kumar Khatri,선웅,Shashi Bala Singh,Dalapathi Gugulothu,Saurabh Srivastava,Lalitkumar Vora 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Since its discovery in 2012, CRISPR Cas9 has been tried as a direct treatment approach to correct the causative gene mutation and establish animal models in neurodegenerative disorders. Since no strategy developed until now could completely cure Parkinson’s disease (PD), neuroscientists aspire to use gene editing technology, especially CRISPR/Cas9, to induce a permanent correction in genetic PD patients expressing mutated genes. Over the years, our understanding of stem cell biology has improved. Scientists have developed personalized cell therapy using CRISPR/Cas9 to edit embryonic and patient-derived stem cells ex-vivo. This review details the importance of CRISPR/Cas9-based stem cell therapy in Parkinson’s disease in developing PD disease models and developing therapeutic strategies after elucidating the possible pathophysiological mechanisms.