An overview of different strategies to introduce conductivity in metal-organic frameworks and miscellaneous applications thereof

Bhardwaj, Sanjeev K.,Bhardwaj, Neha,Kaur, Rajnish,Mehta, Jyotsana,Sharma, Amit L.,Kim, Ki-Hyun,Deep, Akash The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.31

<P>Metal-organic frameworks (MOFs) are known to possess many interesting material properties such as high specific surface area, tailorable porosity, adsorption/absorption capabilities, post-synthetic modifications, and chemical/thermal stabilities. Because of these unique features, they have been explored for the development of sensors for a variety of analytes. A large proportion of pre-existing MOF-based sensors are well suited for optical transductions due to a lack of electrical conduction in their pristine forms. Hence, the development of MOF-based electrochemical/electrical sensors requires specialized strategies through which MOFs are modified or hybridized with enhanced conductive moieties (<I>e.g.</I>, <I>via</I> doping or post synthetic modification). In this review article, we provide a comprehensive review of various synthetic and integrating strategies to improve electrical conductivity and long-range charge transport properties in MOFs. To this end, we have compiled details of different techniques that have been used to develop electrically/electrochemically active platforms for MOF-based sensing of various targets.</P>

Fluorescent nanobiosensors for the targeted detection of foodborne bacteria

Bhardwaj, Neha,Bhardwaj, Sanjeev K.,Nayak, Manoj K.,Mehta, Jyotsana,Kim, Ki-Hyun,Deep, Akash Elsevier 2017 Trends in analytical chemistry Vol.97 No.-

<P>Foodborne diseases caused by bacterial pathogens are severe threats to human health. Conventional culture based microbiologic methods for the analysis of bacterial contamination in food products are laborious, time consuming and require specific skills. Immunologic and polymerase chain reaction (PCR) based molecular methods are also costly, lack specificity, and may yield false results. As outlined in this review, fluorescent nanobiosensors have now become effective alternative tools for rapid and routine detection of foodborne bacteria. We provide an overview of the use of different fluorescent nano materials in the development of nanobiosensors with special emphasis on underlying detection principles, sensitivity, specificity, and their capability of multiplexed analysis. In summary, the diverse nanomaterials used for bacterial detection are critically analyzed with respect to their advantages and limitations for future applications in the diagnosis of foodborne bacteria. (C) 2017 Elsevier B.V. All rights reserved.</P>

MOF–Bacteriophage Biosensor for Highly Sensitive and Specific Detection of <i>Staphylococcus aureus</i>

Bhardwaj, Neha,Bhardwaj, Sanjeev K.,Mehta, Jyotsana,Kim, Ki-Hyun,Deep, Akash American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.39

<P>To produce a sensitive and specific biosensor for Staphylococcus aureus, bacteriophages have been interfaced with a water-dispersible and environmentally stable metal-organic framework (MOF), NH2-MIL-53(Fe). The conjugation of the MOF with bacteriophages has been achieved through the use of glutaraldehyde as cross-linker. Highly sensitive detection of S. aureus in both synthetic and real samples was realized by the proposed MOF-bacteriophage' biosensor based on the photoluminescence quenching phenomena; limit of detection (31 CFU/mL) and range of detection (40 to 4 X 10(8) CFU/mL). This is the first report exploiting the use of an MOF-bacteriophage complex for the biosensing of S. aureus. The results of our study highlight that-the proposed biosensor is more sensitive than most of the previous methods while exhibiting some advanced features like specificity) regenerability, extended range of linear 'detection, and stability for long-term storage (even at room temperature).</P>

Highly sensitive detection of dipicolinic acid with a water-dispersible terbium-metal organic framework

Bhardwaj, Neha,Bhardwaj, Sanjeev,Mehta, Jyotsana,Kim, Ki-Hyun,Deep, Akash Elsevier 2016 Biosensors & bioelectronics Vol.86 No.-

<P><B>Abstract</B></P> <P>The sensitive detection of dipicolinic acid (DPA) is strongly associated with the sensing of bacterial organisms in food and many types of environmental samples. To date, the demand for a sensitive detection method for bacterial toxicity has increased remarkably. Herein, we investigated the DPA detection potential of a water-dispersible terbium-metal organic framework (Tb-MOF) based on the fluorescence quenching mechanism. The Tb-MOF showed a highly sensitive ability to detect DPA at a limit of detection of 0.04nM (linear range of detection: 1nM to 5µM) and also offered enhanced selectivity from other commonly associated organic molecules. The present study provides a basis for the application of Tb-MOF for direct, convenient, highly sensitive, and specific detection of DPA in the actual samples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dipicolinic acid (DPA) is an excellent indicator of bacterial infection. </LI> <LI> In this work, metal organic frameworks (MOFs) are explored as potential DPA detectors. </LI> <LI> Fluorescent detection of DPA is achieved by synthesizing the Tb-MOF ‘Tb(BTC)(H<SUB>2</SUB>O)<SUB>6</SUB>’. </LI> </UL> </P>

Selective hydrolysis of amorphous cellulosic fines for improvement in drainage of recycled pulp based on ratios of cellulase components

Nishi K. Bhardwaj,Nishi K. Bhardwaj,Surendra P. Singh 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.22 No.-

Recycled pulp contains large amount of fines having high surface area and amorphous cellulose. Thesefines adsorb water to large extent and dewatering rate is lower compared to virgin pulp. Selectivehydrolysis of these excess ultra fines through cellulase enzymes can be utilized for enhancing thedrainage rate. The concept of monocomponent cellulase treatment of recycled pulp for improvement indrainage and the understanding whether effectiveness depends on a specific type of cellulasecomponent (endoglucanase/cellobiohydrolase) is described. The improvement of 15–23% in pulpdrainability was achieved along with better paper properties.

Immunomodulatory Effect of Tea Saponin in Immune T-cells and T-lymphoma Cells via Regulation of Th1, Th2 Immune Response and MAPK/ERK2 Signalling Pathway.

Bhardwaj JYOTI,Chaudhary NARENDRA,Hyo Jin SEO,Tai Sun SHIN,Min Yong KIM,Jong Deog KIM 한국생물공학회 2014 한국생물공학회 학술대회 Vol.2014 No.4

Comparative volumetric and clinical evaluation of peri-implant sulcular fluid and gingival crevicular fluid

Bhardwaj, Smiti,Prabhuji, Munivenkatappa Lakshmaiah Venkatesh Korean Academy of Periodontology 2013 Journal of Periodontal & Implant Science Vol.43 No.5

Purpose: Peri-implant sulcular fluid (PISF) has a production mechanism similar to gingival crevicular fluid (GCF). However, limited research has been performed comparing their behavior in response to inflammation. Hence, the aim of the present study was to comparatively evaluate PISF and GCF volume with varying degrees of clinical inflammatory parameters. Methods: Screening of patients was conducted. Based on the perimucosal inflammatory status, 39 loaded implant sites were selected from 24 patients, with equal numbers of sites in healthy, peri-implant mucositis, and peri-implantitis subgroups. GCF collection was done from age- and sex-matched dentate patients, selected with gingival inflammatory status corresponding to the implant sites. Assessment of the inflammatory status for dental/implant sites was performed using probing depth (PD), plaque index/modified plaque index (PI/mPI), gingival index/simplified gingival index (GI/sGI), and modified sulcular bleeding index (BI). Sample collection was done using standardized absorbent paper strips with volumetric evaluation performed via an electronic volume quantification device. Results: Positive correlation of the PISF and GCF volume was seen with increasing PD and clinical inflammatory parameters. A higher correlation of GCF with PD (0.843) was found when compared to PISF (0.771). PISF expressed a higher covariation with increasing grades of sGI (0.885), BI (0.841), and mPI (0.734), while GCF established a moderately positive correlation with GI (0.694), BI (0.696), and PI (0.729). Conclusions: Within the limitations of this study, except for minor fluctuations, GCF and PISF volumes demonstrated a similar nature and volumetric pattern through increasing grades of inflammation, with PISF showing better correlation with the clinical parameters.

A Combined QRS-complex and P-wave Detection in ECG Signal for Ubiquitous Healthcare System

Bhardwaj, Sachin,Lee, Dae-Seok,Chung, Wan-Young The Korea Institute of Information and Commucation 2007 Journal of information and communication convergen Vol.5 No.2

Long term Electrocardiogram (ECG) [1] analysis plays a key role in heart disease analysis. A combined detection of QRS-complex and P-wave in ECG signal for ubiquitous healthcare system was designed and implemented which can be used as an advanced warning device. The ECG features are used to detect life-threating arrhythmias, with an emphasis on the software for analyzing QRS complex and P-wave in wireless ECG signals at server after receiving data from base station. Based on abnormal ECG activity, the server will transfer alarm conditions to a doctor's Personal Digital Assistant (PDA). Doctor can diagnose the patients who have survived from cardiac arrhythmia diseases.

QUANTITATIVE ESTIMATES FOR GENERALIZED TWO DIMENSIONAL BASKAKOV OPERATORS

Bhardwaj, Neha,Deo, Naokant The Kangwon-Kyungki Mathematical Society 2016 한국수학논문집 Vol.24 No.3

In this paper, we obtain quantitative estimates for generalized double Baskakov operators. We calculate global results for these operators using Lipschitz-type spaces and estimate the error using modulus of continuity.

Role of low energy transition metal ions in interface formation in ZnO thin films and their effect on magnetic properties for spintronic applications

Bhardwaj, Richa,Kaur, Baljeet,Singh, Jitendra Pal,Kumar, Manish,Lee, H.H.,Kumar, Parmod,Meena, R.C.,Asokan, K.,Hwa Chae, Keun,Goyal, Navdeep,Gautam, Sanjeev Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.479 No.-

<P><B>Abstract</B></P> <P>In this study, X-ZnO/ZnO/Si(100) (X = Co, Ni and Cu) bilayer structure is fabricated using low energy ion implantation technique. Five different fluences 1 × 10<SUP>15</SUP>, 5 × 10<SUP>15</SUP>, 1 × 10<SUP>16</SUP>, 2.5 × 10<SUP>16</SUP> and 5 × 10<SUP>16</SUP> ions/cm<SUP>2</SUP> with 100 keV ion-beam energy were selected in order to implant the ions up to the depth of ≈44 nm as calculated through Stopping Range of Ion in Matter and Transport Range of Ions in Matter software. Structural modification was investigated by high resolution X-ray diffraction measurements in ZnO bilayer system. An observed systematic 2<I>θ</I> shift in (002) peak with increasing fluence implies increased density of implanted metal ions in ZnO matrix revealing the substitution of implanted ion at Zn-site. The mechanism of bilayer formation by ion-beam implantation technique has been discussed for metal-ions by investigating their interface properties. Atomic force microscopy reveals the morphological modification after ion implantation. Near-edge X-ray absorption fine-structure (NEXAFS) measurements at metal <I>K</I>- and <I>L</I> <SUB>3,2</SUB>-edges have been used to investigate the nature of implanted ions in terms of their valance state and local electronic environment. Further, O <I>K</I>-edge NEXAFS measurement for Ni-ZnO/ZnO/Si bilayer is highly sensitive to incident beam angles whereas no spectral change is seen for Zn <I>L</I>-edge measurements. The magnetic measurements were performed via vibrating sample magnetometer that showed the films are ferromagnetic at room temperature. The origin of ferromagnetism has been understood through defect mediated bound magnetic polaron model. Further, perpendicular magnetic anisotropy is also observed for Ni-ZnO/ZnO/Si bilayer structure at room temperature, which is correlated with the angle dependent O K-edge NEXAFS measurements. Fabrication of ZnO bilayer via ion implantation and investigation of above properties may prove useful in spin related and optoelectronic applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Observance of RTFM in metal ion-implanted Ni-ZnO/ZnO/Si bilayer </LI> <LI> HRXRD and NEXAFS measurements confirms the wurtzite phase and Zn<SUP>2+</SUP> substitution in ZnO matrix. </LI> <LI> Angle dependent NEXAFS measurements provides the evidence of observed PMA. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>Mechanism of ion beam interaction X (X = Co, Ni and Cu) with ZnO lattice forming X-ZnO/ZnO/Si(100) bilayer structure. Films were implanted using a multi cathode source of negative-ions by cesium sputtering (MC-SNICS) and with the increasing ion flux, X can undergo one of two mechanisms of either substituting the Zn-site or occupy interstitial position in ZnO matrix. Angle dependent O K-edge NEXAFS measurements provides the evidence of perpendicular magnetic anisotropy in ZnO bilayer. </P> <P>[DISPLAY OMISSION]</P>