Improved chaos-based video steganography using DNA alphabets

Nirmalya Kar,Kaushik Mandal,Baby Bhattacharya 한국통신학회 2018 ICT Express Vol.4 No.1

DNA based steganography plays a vital role in the field of privacy and secure communication. Here, we propose a DNA properties-based mechanism to send data hidden inside a video file. Initially, the video file is converted into image frames. Random frames are then selected and data is hidden in these at random locations by using the Least Significant Bit substitution method. We analyze the proposed architecture in terms of peak signal-to-noise ratio as well as mean squared error measured between the original and steganographic files averaged over all video frames. The results show minimal degradation of the steganographic video file.

Time-Dependent Controlof Hole-Opening Degree of Porous ZnO Hollow Microspheres

Tripathy, Nirmalya,Ahmad, Rafiq,Jeong, Han-Sol,Hahn, Yoon-Bong American ChemicalSociety 2012 Inorganic Chemistry Vol.51 No.2

<P>Well-designed, monodispersed porous ZnO hollow microsphereswithcontrolled hole-opening were successfully synthesized by a faciletwo-step solution route at low temperature. The hollow microsphereshaving average diameter of 3–4 μm showed time-dependenthole-opening, i.e. 4–100% for 15–75 min. The hole-openingpercentage increases linearly with time until complete opening. TheZnO hollow microspheres also exhibited a high surface area (34 m<SUP>2</SUP> g<SUP>–1</SUP>), a large pore volume (0.19 cm<SUP>3</SUP> g<SUP>–1</SUP>) and an average pore diameter of 3.8nm. A plausible growth mechanism for the formation of ZnO hollow microsphereswas also proposed.</P><P>Well-designed, monodispersed porous ZnOhollow microsphereswith controlled hole-opening were synthesized by a facile low temperature,two-step solution route. The hollow microspheres having average diameterof 3−4 μm showed time-dependent hole-opening. The hole-openingpercentage increases linearly with time until complete opening. TheZnO hollow microspheres also exhibited high surface area, large porevolume and average pore diameter of 3.8 nm. A plausible growth mechanismfor the formation of ZnO hollow microspheres was also proposed.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2012/inocaj.2012.51.issue-2/ic2022598/production/images/medium/ic-2011-022598_0005.gif'></P>

Enhanced anticancer potency using an acid-responsive ZnO-incorporated liposomal drug-delivery system

Tripathy, Nirmalya,Ahmad, Rafiq,Ko, Hyun Ah,Khang, Gilson,Hahn, Yoon-Bong The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.9

<P>The development of stimuli-responsive nanocarriers is becoming important in chemotherapy. Liposomes, with an appropriate triggering mechanism, can efficiently deliver their encapsulated cargo in a controlled manner. We explored the use of acid-sensitive zinc oxide nanoparticles (ZNPs) as modulators of the responsive properties of liposomes. Nanocomplexes formed by the incorporation of ZNPs in liposomes (ZNP-liposomes) were designed to demonstrate the pH-responsive release of a drug (daunorubicin) without premature drug leakage and with the maintenance of the relevant therapeutic concentrations. The nanocomplexes were spherical in shape with a narrow size distribution and showed a high drug-encapsulating efficiency. Under acidic conditions, the ZNP-liposome nanocomplexes released the loaded drug more rapidly than bare liposomes. Using flow cytometry, confocal microscopy and an MTT assay, we demonstrated that these nanocomplexes were readily taken up by cancer cells, resulting in significantly enhanced cytotoxicity. On exposure to the acidic conditions inside cancer cells, the ZNPs rapidly decomposed, releasing the entrapped drug molecules from the ZNP-liposome nanocomplexes, producing widespread cytotoxic effects. The incorporated ZNPs were multimodal in that they not only resulted in a pH-responsive drug-delivery system, but they also had a synergistic chemo-photodynamic anticancer action. This design provides a significant step towards the development of multimodal liposome structures.</P>

Tailored lysozyme–ZnO nanoparticle conjugates as nanoantibiotics

Tripathy, Nirmalya,Ahmad, Rafiq,Bang, Seung Hyuck,Min, Jiho,Hahn, Yoon-Bong The Royal Society of Chemistry 2014 Chemical communications Vol.50 No.66

<P>Covalently attached lysozyme–ZnO nanoparticle (L–ZNP) conjugates were synthesized by a low temperature solution route. Tailored L–ZNP conjugates exhibit pronounced antibacterial features against <I>Escherichia coli</I> (<I>E. coli</I>) and <I>Staphylococcus aureus</I> (<I>S. aureus</I>).</P> <P>Graphic Abstract</P><P>Covalently attached lysozyme–ZnO nanoparticle conjugates exhibit pronounced antibacterial features against <I>Escherichia coli</I> and <I>Staphylococcus aureus</I>. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cc03712j'> </P>

Metal oxide modified ZnO nanomaterials for biosensor applications

Tripathy Nirmalya,Kim Deok-Ho 나노기술연구협의회 2018 Nano Convergence Vol.5 No.27

Advancing as a biosensing nanotechnology, nanohybrids present a new class of functional materials with high selectivity and sensitivity, enabling integration of nanoscale chemical/biological interactions with biomedical devices. The unique properties of ZnO combined with metal oxide nanostructures were recently demonstrated to be an efficient approach for sensor device fabrication with accurate, real-time and high-throughput biosensing, creating new avenues for diagnosis, disease management and therapeutics. This review article collates recent advances in the modified ZnO nanostructured metal oxide nanohybrids for efficient enzymatic and non-enzymatic biosensor applications. Furthermore, we also discussed future prospects for nanohybrid materials to yield high-performance biosensor devices.

Multi-synergetic ZnO platform for high performance cancer therapy

Tripathy, Nirmalya,Ahmad, Rafiq,Ah Ko, Hyun,Khang, Gilson,Hahn, Yoon-Bong The Royal Society of Chemistry 2015 Chemical communications Vol.51 No.13

<P>ZnO platforms were evaluated for designing a high-performance anticancer drug (daunorubicin) carrier. Hollow structured ZnO, compared with nanorods, acts as a multi-purpose entity by serving as smart carriers and exhibiting synergetic photodynamic cytotoxic effects, which are ascribed to their high-specific surface area, hollow interior, pH-responsiveness and inherent photodynamism.</P> <P>Graphic Abstract</P><P>Hollow structured ZnO with high-performance drug-encapsulation for acid-triggered, chemo-photodynamic cancer therapy. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cc10037a'> </P>

Outstanding Antibiofilm Features of Quanta-CuO Film on Glass Surface

Tripathy, Nirmalya,Ahmad, Rafiq,Bang, Seung Hyuck,Khang, Gilson,Min, Jiho,Hahn, Yoon-Bong American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.24

<P>Intelligently designed surface nanoarchitecture provides defined control over the behavior of cells and biomolecules at the solid liquid interface. In this study, CuO quantum dots (quanta-CuO; similar to 3-5 nm) were synthesized by a simple, low-temperature solution process and further formulated as paint to construct quanta-CuO thin film on glass. Surface morphological characterizations of the as-coated glass surface reveal a uniform film thickness (similar to 120 +/- 10 nm) with homogeneous distribution of quanta-CuO. The antibiofilm assay showed a very high contact bacteria-killing capacity of as coated quanta-CuO glass surfaces toward Staphylococcus aureus and Escherichia coli. This efficient antibacterial/antibiofilm activity was ascribed to the intracellular reactive oxygen species (ROS) generated by the quanta-CuO attached to the bacterial cells, which leads to an oxidative assault and finally results in bacterial cell death. Although there is a significant debate regarding the CuO nanostructure's antibacterial mode of action, we propose both contact killing and/or copper ion release killing mechanisms for the antibiofilm activity of quanta-CuO paint. Moreover, synergism of quanta-CuO with conventional antibiotics was also found to further enhance the antibacterial efficacy of commonly used antibiotics. Collectively, this state-of-the-art design of quanta-CuO coated glass can be envisioned as promising candidates for various biomedical and environmental device coatings.</P>

In vivo Bone Regeneration Evaluation of Duck’s Feet Collagen/PLGA Scaffolds in Rat Calvarial Defect

송정은,Nirmalya Tripathy,신재훈,이대훈,차재근,박찬흠,서동삼,강길선 한국고분자학회 2017 Macromolecular Research Vol.25 No.10

Tissue engineered bone substitutes should mimic natural bone characteristics to be highly-suitable for treating bone defects in addition to its biocompatibility and good mechanical stability. In this study, we performed a detailed in vivo bone regeneration evaluation of 80wt% duck’s feet collagen/poly(lactide-co-glycolide) scaffolds (DC/ PLGA) fabricated by solvent casting/salt leaching strategy in a rat calvarial defect as model. We have already shown a strong influence of DC/ PLGA scaffolds on bone regeneration in terms of biomaterial cohesion, architecture, mechanical features, and in vitro biological properties. The as-fabricated scaffold has shown significant increase in osteogenesis, initial bone formation and differentiation, ascribed to the high percentage of DC in the 80wt% DC/PLGA scaffold. The in vivo implanted scaffold was found be well-attached to the bone defect region and eventually gets integrated with the surrounding tissues without any pronounced inflammatory reactions. Compared to bare PLGA, an increased recovery in bone volume was observed at 8th week post-surgery. Thus, the 80 wt% DC/PLGA scaffold can be envisioned as a potential alternative bone graft in bone tissue engineering.

CdS nanoparticle coated carbon nanotube through magnetron sputtering and its improved field emission performance

Supratim Maity,Nirmalya Sankar Das,Saswati Santra,D. Sen,Kalyan Kumar Chattopadhyay 한국물리학회 2016 Current Applied Physics Vol.16 No.10

Carbon nanotubes (CNTs) are the most famous cold cathodes for display technology. However, graphene and other two dimensional carbon nanostructures and advanced II-VI semiconductor nanostructures are strongly emerging as strong competitors challenging the well established performance of CNTs in this field. Hence several technologies to improve field emission (FE) properties of CNTs are being developed. Here we report a facile technique to improve the cold emission performance of multiwalled CNTs (MWCNTs) by coating the same with chalcogenide semiconductor. MWCNT thin films were synthesized via chemical vapor deposition (CVD) technique and the same was coated by cadmium sulfide (CdS) nanoparticles via radio frequency magnetron sputtering technique. The pure and coated thin films were characterized by Fourier transform infrared spectroscopy and Raman spectroscopy to confirm presence of CdS on CNT surfaces. X-ray photoelectron spectroscopy revealed the compositional and valance state information of the as prepared samples. Field emission scanning electron microscopy and high resolution transmission electron microscopic studies were carried out to obtain information regarding morphology and nanocrystallinity of the CNTs and the coated CdS nanoparticles. Field assisted electron emission of pristine CNTs developed significantly with improved turn-on field and very high current density by CdS nanoparticle coating.

Silk Fibroin Scaffolds as a Transporter to Deliver Demineralized Bone Particles for Bone Defect Treatment

국현,김은영,Nirmalya Tripathy,송정은,강길선 한국고분자학회 2015 한국고분자학회 학술대회 연구논문 초록집 Vol.2015 No.10