Nataraja Sekhar Yadavalli

Nataraja Sekhar Yadavalli
University of Georgia | UGA · Nanostructured Materials Lab

Dr. rer. nat.

About

55
Publications
9,986
Reads
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714
Citations
Introduction
My research interests are in the innovation of novel materials with the interface of Chemistry, Biology and Physics. Specifically, the development of Nanobiocatalysts, Nanomaterials and Nanofabrication technologies, and highly sensitive microscopy and spectroscopy instruments to facilitate the materials, surface and interfacial characterization.
Additional affiliations
February 2015 - August 2021
University of Georgia
Position
  • Research Scientist
July 2014 - January 2015
Universität Potsdam
Position
  • Researcher
Education
November 2010 - July 2014
Universität Potsdam
Field of study
  • Experimental Physics
October 2008 - December 2010
University of Freiburg
Field of study
  • Microsystems Engineering

Publications

Publications (55)
Article
In this paper two groups supporting different views on the mechanism of light induced polymer deformation argue about the respective underlying theoretical conceptions, in order to bring this interesting debate to the attention of the scientific community. The group of Prof. Nicolae Hurduc supports the model claiming that the cyclic isomerization o...
Article
Full-text available
In this paper, we report on differences in the response of photosensitive azobenzene containing films upon irradiation with the intensity or polarization interference patterns. Two materials are studied differing in the molecular weight: an azobenzene-containing polymer and a molecular glass formed from a much smaller molecule consisting of three c...
Article
We use a photosensitive layer containing azobenzene moieties to map near field intensity patterns in the vicinity of nano grids fabricated within a thin silver layer. It is known that azobenzene containing films deform permanently during irradiation, following the pattern of the field intensity. The photosensitive material reacts only to stationary...
Article
When photosensitive azobenzene-containing polymer films are irradiated with light interference patterns, topographic variations in the film develop that follow the local distribution of the electric field vector. The exact correspondence of e.g., the vector orientation in relation to the presence of local topographic minima or maxima is in general...
Article
It is well-known that surface plasmon generated near fields of suitably irradiated metal nano-structures can induce a patterning in an azobenzene-modified photosensitive polymer film placed on top. The change in the topography usually follows closely and permanently the underlying near field intensity pattern. With this approach, one can achieve a...
Article
Full-text available
Textiles that are smart and responsive have become the new norm in recent years. The development of smart textiles has sparked research into self-powered distributed sensors and portable wearable electronics integrated into clothing. One of the main functionalities of smart textiles is the ability to power these electronics by generating electrical...
Article
We present a straightforward and easily interpretable multi-scale infrared (IR) spectroscopic characterization of anisotropy and arrangement of polymer nanofibers. Direct spectral interpretation of fiber bundles and single fibers with respect to their anisotropic properties is possible by applying non-invasive IR polarimetry at defined polarization...
Article
Full-text available
The concept of nanogenerators (NGs) based on textiles was introduced to impart functional attributes to textiles for developing smart textiles and integrating wearable electronics of various functionalities. The human body can generate sufficient mechanical energy that can be harvested by the piezoelectric nanogenerators (PENGs) and used to power u...
Article
The mechanism of separation methods, e.g. liquid chromatography, is realized through rapid multiple adsorption-desorption steps leading to the dynamic equilibrium state in a mixture of molecules with different partition coefficients. Sorting of colloidal particles, including protein complexes, cells, and viruses, is limited due to a high energy bar...
Article
The mechanism of separation methods, e.g. liquid chromatography, is realized through rapid multiple adsorption-desorption steps leading to the dynamic equilibrium state in a mixture of molecules with different partition coefficients. Sorting of colloidal particles, including protein complexes, cells, and viruses, is limited due to a high energy bar...
Article
In article number 1907422, Sergiy Minko and co‐workers introduce a gravitational fiber drawing method for the fabrication of monofilament nano‐ and microfibers and assemble them in highly ordered 3D arrays with controllable interfiber spacing and fiber angular orientation. The complex 3D constructs are made of fibers with different diameters, draw...
Article
This work introduces a gravity fiber drawing (GFD) method of making single filament nanofibers from polymer solutions and precise alignment of the fibers in 3D scaffolds. This method is advantageous for nanofiber 3D alignment in contrast to other known methods. GFD provides a technology for the fabrication of freestanding filament nanofibers of wel...
Article
A simple and versatile touchspinning method is demonstrated for the fabrication of core-sheath nanofibrous piezoelectric yarns with a single filament electroconductive core. The polyvinylidene fluoride (PVDF) piezoelectric nanofibers are fabricated in a continuous spinning process with relatively controlled structure, orientation, and dimensions to...
Article
We report a “grafting through” conjugation strategy to improve lysozyme catalytic activity and thermal stability by the synthesis of a synthetic polymer–enzyme hybrid. The lysozyme was first conjugated with glycidyl methacrylate via ring-opening reaction between epoxy groups and lysine residues of the enzyme to synthesize the enzyme macromonomer. T...
Article
Herein, we report a conjugation strategy, where we utilize a polyethylene oxide cylindrical molecular brush architecture to design a self-assembled structure for thermal stabilization of enzymes. We demonstrate that the proposed architecture of the moderately stiff polymer ligand results in a significant improvement of biocatalytic activity and the...
Article
Full-text available
We demonstrate in situ recorded motion of nano-objects adsorbed on a photosensitive polymer film. The motion is induced by a mass transport of the underlying photoresponsive polymer material occurring during irradiation with interference pattern. The polymer film contains azobenzene molecules that undergo reversible photoisomerization reaction from...
Article
Herein we report a robust, highly selective, and efficient method to prepare dense poly(ethylene glycol) (PEG) polymer brushes on silicon substrates via solvent-free, catalyst-free, strain-promoted acetylene azide cycloaddition (SPAAC) reaction. First, poly(glycidyl methacrylate) was grafted to the silicon substrate as an anchoring layer to immobil...
Article
Here, we report on two photosensitive amorphous polymers showing opposite behavior upon exposure to illumination. The first polymer (PAZO) consists of linear backbone to which azobenzene-containing side chains are covalently attached, while in the second polymer (azo-PEI), the azobenzene side chains are attached ionically to a polyelectrolyte backb...
Article
Surface Relief Gratings (SRGs) are inscribed in the Au-coated azobenzene containing photosensitive polymer films on a glass substrate. The structures consist of micrometer-period sinusoidal patterns of sub-micron amplitudes, formed by photo-isomerization and molecular reorientation processes in the polymer film during exposure to the light interfer...
Article
AbstractIn this paper we report on the interaction between photosensitive azobenzene-containing polymer films and on top adsorbed graphene multilayers. The photosensitive polymer film changes its topography under irradiation with light interference patterns according to their polarization distribution. The multilayer graphene follows the deformatio...
Conference Paper
Full-text available
When azo-modified photosensitive polymer films are irradiated with light interference patterns, topographic variations in the film develop that follow the E ⃗-field vector distribution resulting in the formation of surface relief grating (SRG). The exact correspondence of the E ⃗-field vector orientation in interference pattern in relation to the p...
Article
In this paper we show how graphene can be utilized as a nanoscopic probe in order to characterize local opto-mechanical forces generated within photosensitive azobenzene containing polymer films. Upon irradiation with light interference patterns, photosensitive films deform according to the spatial intensity variation, leading to the formation of p...
Article
Azo-modified photosensitive polymers offer the interesting possibility to reshape bulk polymers and thin films by UV-irradiation while being in the solid glassy state. The polymer undergoes considerable mass transport under irradiation with a light interference pattern resulting in the formation of surface relief grating (SRG). The forces inscribin...
Thesis
Full-text available
When azobenzene-modified photosensitive polymer films are irradiated with light interference patterns, topographic variations in the film develop that follow the E-field vector distribution resulting in the formation of surface relief grating (SRG). The exact correspondence of the E-field vector orientation in interference pattern in relation to th...
Article
We have used polarized confocal Raman microspectroscopy and scanning near-field optical microscopy with a resolution of 60 nm to characterize photoinscribed grating structures of azobenzene doped polymer films on a glass support. Polarized Raman microscopy allowed determining the reorientation of the chromophores as a function of the grating phase...
Conference Paper
Full-text available
There is a growing interest on having an integrated electronic functionality over three dimensional large area surfaces for over decade (viz., paper like thin displays on furniture, interconnects, robot sensor skin, intelligent medical bandages or surgical tools etc).1-4 Flexible polymer substrates sandwiched with electronic circuitry are increasin...
Article
Full-text available
I n microfabrication processes, ultra-thin metallized polymers are commonly prepared using physical vapor deposition of a metal film on the polymer surface. During the deposition process, it is often expected that the metal layer will defuse into the polymer surface, thereby creating a bonding/sandwich layer near the metal/polymer interface. In thi...
Article
In this paper, we show how graphene can be utilized as a nanoscopic probe in order to characterize local opto-mechanical forces generated within photosensitive azobenzene containing polymer films. Upon irradiation with light interference patterns, photosensitive films deform according to the spatial intensity variation, leading to the formation of...
Article
We report on conductivity behavior of very thin gold layer deposited on a photosensitive polymer film. Under irradiation with light interference pattern, the azobenzene containing photosensitive polymer film undergoes deformation at which topography follows a distribution of intensity, resulting in the formation of a surface relief grating. This pr...
Article
We have used polarized confocal Raman microspectroscopy and scanning near-field optical microscopy with a resolution of 60 nm to characterize photoinscribed grating structures of azobenzene doped polymer films on a glass support. Polarized Raman microscopy allowed determining the reorientation of the chromophores as a function of the grating phase...
Article
In this paper, we report on in-situ atomic force microscopy (AFM) studies of topographical changes in azobenzene-containing photosensitive polymer films that are irradiated with light interference patterns. We have developed an experimental setup consisting of an AFM combined with two-beam interferometry that permits us to switch between different...
Conference Paper
Full-text available
There is a growing interest on having an integrated electronic functionality over three dimensional large area surfaces for over decade (viz., paper like thin displays on furniture, interconnects, robot sensor skin, intelligent medical bandages or surgical tools etc).1-4 Flexible polymer substrates sandwiched with electronic circuitry are increasin...
Article
The interface between thin films of metal and polymer materials play a significant role in modern flexible microelectronics viz., metal contacts on polymer substrates, printed electronics and prosthetic devices. The major emphasis in metal-polymer interface is on studying how the externally applied stress in the polymer substrate leads to the defor...
Article
We report on reversible structuring of photosensitive azo-containing polymer films induced by near-field intensity patterns emanating from illuminated nano-scale metal structures fabricated by colloidal lithography. Two different sets of these nano-antennas, consisting of either gold or silver, were investigated with respect to their ability to ind...
Thesis
Full-text available
In this thesis, the fabrication and characterization of a novel type of hybrid azobenzene modified photosensitive polymer film with a metallic nano-antennas integrated into the substrate is presented. For instance, we use these substrates for the manipulation of adsorbed nano-objects. For the past decade, there is a growing demand on methods for pr...
Article
Homodimerization of the retinoid X receptor (RXR) occurs upon binding of ligands to the receptor, but little is known about structural mechanisms involved in RXR ligand binding. In the present study, binding of known ligands (5-Hydroxytryptamine, dopamine and naloxone) to the Celuca pugilator RXR was modeled computationally using the human RXR-α as...
Conference Paper
Full-text available
There is a strong demand on methods for precise manipulation of nanoobjects on surfaces. Recently we report on a phenomenon observed with a certain type of thin polymer films, suggesting that the substrate by itself can induce motion of adsorbed objects (Santer, 2006). The proposed mechanism of motion is based on a dynamically fluctuating force fie...
Technical Report
Full-text available
The Design Objecive was to build a reconfigurable set of components which can be used to build up any system. To meet this, mechanical parts such as supporting blocks, compliant hinges and optical device holders were designed to build a LEGO‐like‐system and manufactured out of a Silicon Wafer by means of Silicon ICP process. Using the FRDPARRC anal...
Article
Aminoglycoside mimetics inhibit bacterial translation by interfering with the ribosomal decoding site. To elucidate the structural properties of these compounds important for antibacterial activity, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were applied to a set of 56 aminoglycosides...
Article
With the objective to design new chemical entities with enhanced inhibitory potencies against p38 MAP alpha kinase, the 3D-QSAR and Comparative Molecular Field Analysis (CoMFA) studies were carried out on triazolopyridine oxazole compounds as inhibitors of these kinase is presented here. The developed model gave q(2) value of 0.707 and r(2) value o...
Article
In the present study, a series of 179 quinoline and quinazoline heterocyclic analogues exhibiting inhibitory activity against Gastric (H+/K+)-ATPase were investigated using the comparative molecular field analysis (CoMFA) and comparative molecular similarity indices (CoMSIA) methods. Both the models exhibited good correlation between the calculated...
Article
Three-dimensional quantitative structure-activity relationship (3D-QSAR) models were developed for 46 triazafluorenone derivatives, inhibiting metabotropic glutamate receptor subtype 1 (mGluR1). It includes molecular field analysis (MFA) and receptor surface analysis (RSA). The QSAR model was developed using 35 compounds and its predictive ability...
Article
A 3D- QSAR model os Comparative Molecular Field Analysib (CoMFA) of 45 quinoline derivatives as metaborropic glutamate receptor subtype 1 (mGluR1) inhibitors wew investigated. The CoMFA analysis provided a model with q(2) value of 0.827 and r(2) value of 0.990, in which q(2) value of 0.827 and an r(2) value of 0.990, in which the good correlation b...
Article
Full-text available
Motivation. The p38 kinase plays a vital role in the inflammation mediated by tumor necrosis factor- α (TNF-α) and interleukin-1β (IL-1β) pathways and inhibitors of p38 kinase provide effective approach for the treatment of inflammatory diseases. Three dimensional quantitative structure activity relationship (3D QSAR) studies involving comparative...
Article
Full-text available
Motivation. Glutaminyl cyclase (QC), besides its crucial role in hormone maturation and its pathophysiological involvement in Alzheimer's disease, is a new potential drug target. To understand the structural requirements of QC ligands and to design new ligands against human glutaminyl cyclase with enhanced inhibitory potency we performed a 3D-QSAR...
Article
Full-text available
The effect of different biowastes such as paddy straw, sorghum straw, sugarcane molasses, saw dust and paper waste on the growth and biochemical constituents of oyster mushroom (Pleurotus florida) was studied. Favourable conditions were created to attain the maximum yield of mushrooms. The results reveled that mushroom growth was better in paddy st...
Article
Full-text available
The objective of this study was to develop a rapid system for regeneration of the important medicinal plant, Ocimum gratissimum L, from nodal explant. Single node explants were inoculated on basal MS (Murashige and Skoog, 1962) medium containing 3% (w/v) sucrose, supplemented with different concentrations and combinations of 6-benzylaminopurine (BA...

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Projects (2)
Project
Encapsulation of enzymes with polymer shell to improve its biocatalytic performance and stability against thermal denaturation.