Ramakrishna Vasireddi

SOLEIL synchrotron · Microfluidics Laboratory

Well-defined aerosols pave the way for versatile basic and applied research. Here, we demonstrate a unique whipping instability that generates from a high-aspect-ratio microfluidic device resulting in a unique steady-state gas-focused whipping jet (WJ) without any need for electrification. This WJ device emanates a multi-monodisperse whipping spray...

The identification of protein crystals naturally occurring inside cells and organisms has opened a window for a new type of macromolecular crystallography (MX) and structural biology, referred to as in vivo MX. In the past decade, there have been efforts to obtain deeper insights into the yet uncontrollable events dictating in vivo crystal growth,...

Cyclic-olefin-copolymer (COC)-based microfluidic devices are increasingly becoming the center of highly valuable research for in situ X-ray measurements due to their compatibility with X-rays, biological compounds, chemical resistance, optical properties, low cost, and simplified handling. COC microfluidic devices present potential solutions to cha...

An approach for serial crystallography experiments based on wedged-data collection is described. This is an alternative method for recording in situ X-ray diffraction data on crystalline samples efficiently loaded in an X-ray compatible microfluidic chip. Proper handling of the microfluidic chip places crystalline samples at geometrically known pos...

Synthesis of graphene with reduced use of chemical reagents is essential for manufacturing scale-up and to control its structure and properties. In this paper, we report the mechanism for exfoliating graphene from graphite slabs using laser impulse. We set up a molecular dynamics model that accounts for the charge-mediated inter-atomic potential al...

High-density microfluidics is becoming an important experimental platform for studying complex biological systems such as synthetic gene regulatory networks, molecular biocomputating of engineered cells, distributing rapid point-of-care diagnosis, and monitoring pathological environment. Imaging transient bio-chemical reactions happening in these s...

Synthesis of graphene with reduced use of chemical reagents is essential for manufacturing scale-up and to control its structure and properties. In this paper, we report on a novel chemical-free mechanism of graphene exfoliation from graphite using laser impulse. Our experimental setup consists of a graphite slab irradiated with an Nd:YAG laser of...

The recent developments of several X-ray synchrotrons and (ultrabright) XFEL light sources with increasingly narrow and brilliant beams have allowed facilities to reduce both sample volume and data acquisition time. Moreover, this has created new opportunities for investigating versatile sample conditions while simultaneously increasing demands in...

Free liquid jets are a common sample delivery method in serial femtosecond x-ray (SFX) crystallography. Gas dynamic virtual nozzles (GDVNs) use an outer gas stream to focus a liquid jet down to a few micrometers in diameter. Such nozzles can be fabricated through various methods (capillary grinding, soft lithography, digital light processing, and t...

A microfluidic laboratory recently opened at Synchrotron SOLEIL, dedicated to in-house research and external users. Its purpose is to provide the equipment and expertise that allow the development of microfluidic systems adapted to the beamlines of SOLEIL as well as other light sources. Such systems can be used to continuously deliver a liquid samp...

This paper reports the core−shell structure effects in calcium alginate (CaALG) microbeads due to the threshold water level for phase transition and correlates these properties with respect to pH and electrical conductivity. Further, in this study, we used a novel microfluidic device for drug release testing to study the programmed release of rised...

Uniform endless fibers are ubiquitous and their applications range from functional textiles over biomedical engineering to high-performance filtering and drug delivery systems. Here, we report a new method for the direct, reproducible fabrication of uniform polymer and composite micro-/nanofibers using a microfluidic gas flow focusing nozzle (Gas D...

Advances in modern interface- and material sciences often rely on the understanding of a system’s structure-function relationship. Designing reproducible experiments that yield in situ time-resolved structural information at fast time scales are therefore of great interest, e.g. for better understanding the early stages of self-assembly or other ph...

Rapid prototyping via laser micromachining; microfluidic sample environment; mixing and convection; continuous-flow SAXS measurements; static SAXS measurements; the Porod invariant; DLS analysis; and solvent compatibility study

The effects of mixed metal oxides (CexZr1−xO2) nanoparticle dispersion on the mechanical properties and fracture mechanisms of epoxy polymer matrix and its composite with glass fiber system are reported in this paper. CexZr1−xO2 nanoparticles are synthesized using sol–gel method, and its crystallinity is optimized. Epoxy nanocomposites are synthesi...

Barium soda lime phosphosilicate [(58SiO2–(32 − x)BaO–xCao–6Na2O–4P2O5 (where x = 15, 20, 25 and 30 mol%)] samples were synthesised using conventional sol–gel method at 700 °C sintering temperature. Thermal, structural properties were studied using thermo gravimetric analysis and differential thermal analysis, X-ray diffraction, scanning electron m...

In the present work, we report on the effect of the CaO/Na2O ratio on Non-Bridging Oxygen/Bridging Oxygen (NBO/BO) ratio for sol-gel synthesized 58SiO2-(38-x)CaO-xNa2O-4P2O5 glasses and establish the correlation between Hydroxy Carbonated Apatite layer (HCA) forming ability and the dissolution behaviour in simulated body fluid (SBF) solution. Therm...

Electronic waste recycling via cryo-milling and nanoparticle beneficiation

Electronic waste recycling via cryo-milling and nanoparticle beneficiation

Zinc oxide (ZnO) nanorods of various morphologies are grown on zinc substrate by pressure-assisted hydrothermal process and the growth mechanism is investigated with the help of molecular dynamics (MD) simulation results. Hydrothermally reacted ZnO2 nanostructure bottom-up formation from Zn substrate is a useful process employed here. A systematic...

In the present work, the effect of the CaO/P2O5 ratio on the composition of sol-gel synthesized 58SiO2-(19-x)P2O5-(23+x)CaO (x = 0, 5, 10 and 15 mol %) glass samples was studied. Further, the effect of NBO/BO ratio on hydroxy carbonated apatite layer (HCA) forming ability based on dissolution behavior in simulated body fluid (SBF) solution was also...

The existing methods for recycling electronic wastes such as the printed circuit boards (PCB), which contains a large number of components and elements, face significant challenges when considering environmentally benign and easily separable disposal targets. We report here a low-temperature ball milling method that breaks down PCBs all the way int...

Osteoporosis therapeutics has been monopolized mainly by bisphosphonates, which are potent anti-osteoporotic drugs, while they do not promote bone formation or replenish the already resorbed bone. Although strontium substituted hydroxyapatite (SrHA) has been proclaimed to improve bone properties in an osteoporotic animal model, there is no publishe...

The synthesis of γ-Fe2O3 nanoparticles of varying particle size has been achieved using different molar concentrations of sodium hexametaphosphate while the effect of changing pH has been studied. Iron chloride, sodium hexametaphosphate and sodium hydroxide are used as precursor, reducing agent and accelerator respectively. The synthesized γ-Fe2O3...

Abstract In the last two decades, additive manufacturing (AM) has made significant progress towards the fabrication of biomaterials and tissue engineering constructs. One direction of research is focused on the development of mechanically stable implants with patient-specific size/shape and another direction has been to fabricate tissue-engineered...

In this paper, we demonstrate a novel method of specific or target DNA binding and release, which is achieved by controlling light. Controlled binding and release of molecules play very important role, particularly considering the fact that a large number of nanostructures reported in published literature can be designed as probe or marker but the...

The emission intensity of fluorophore molecule may change in presence of strong plasmon field induced by nanoparticles. The enhancement intensity is optimized through selective clustering or functionalization of nanoparticles in closed vicinity of fluorophore. Our study is aimed at understanding the enhancement mechanism of fluorescence intensity i...

Purpose – The purpose of this paper is to investigate the possibility to construct tissue-engineered bone repair scaffolds with pore size distributions using rapid prototyping techniques. Design/methodology/approach – The fabrication of porous scaffolds with complex porous architectures represents a major challenge in tissue engineering and the de...

Interfacial properties of Shape Memory Alloy (SMA) reinforced polymer matrix composites can be enhanced by improving the interfacial bonding. This paper focuses on studying the interfacial stresses developed in the SMA-epoxy interface due to various laser shot penning conditions. Fiber-pull test-setup is designed to understand the role of mechanica...

Optofluidic schemes of inhibition, transport and activation by carrier molecules through cell membrane have interesting applications. Through plasmonic excitation of nanoparticles integrated in microfluidic channel, we observe cell membrane structural changes. Related phenomena are studied in situ in a microfluidic channel via fluorescence imaging....

By using a novel microfluidic set-up for drug screening applications, this study examines delivery of a novel risedronate based drug formulation for treatment of osteoporosis that was developed to overcome the usual shortcomings of risedronate, such as its low bioavailability and adverse gastric effects. Risedronate nanoparticles were prepared usin...

The bioactive mechanism and influence of network modifiers on soda lime phosphosilicate glasses is the core of the many current medical applications of biomaterials, such as tissue engineering. In this paper, we present our work on bioactive soda lime phosphosilicate glasses with chemical formula 58SiO 2-(38-x) CaO-xNa 2 O-4P 2 O 5 (x= 5, 10, 15 an...

Detection of pathogens from infected biological samples through conventional process involves cell lysis and purification. The main objective of this work is to minimize the time and sample loss, as well as to increase the efficiency of detection of biomolecules. Electrical lysis of medical sample is performed in a closed microfluidic channel in a...

We report an environmentally benign method for the preparation of AgcoreCushell nanocrystallites by a simple transmetallation reaction, wherein the surface silver atoms act as localized reducing agents for the copper ions in solution. Gelatine, glucose and NaOH are used as stabilizer, reducing agent and accelerator respectively. The synthesized Agc...

Disuse by bed rest, limb immobilization or space flight causes rapid bone loss by arresting bone formation and accelerating bone resorption. Propranolol (a non-selective β-adrenergic antagonist) has been shown to improve bone properties by increasing bone formation and decreasing bone resorption in an ovariectomy-induced rat model. However, no stud...

The synthesis of silver nanoparticles of varying size has been achieved using different molar concentrations of NaOH while the effect of changing the temperature has been studied. AgNO3, gelatine, glucose and NaOH are used as a silver precursor, stabilizer, reducing agent and accelerator respectively. The synthesized nanoparticles have been charact...

Silver nanoparticles (Ag-NPs) were successfully synthesized in the natural polymeric matrix. Here we report on the effect of NaOH in preparing polymer synthesis of Ag-NPs using chemical method. Silver nitrate, gelatin, glucose and sodium hydroxide are used as silver precursor, stabilizer, reducing agent and accelerator reagent, respectively. Format...

Silver nanoparticles (Ag-NPs) were successfully synthesized in the natural polymeric matrix. Here we report on the effect of NaOH in preparing polymer synthesis of Ag-NPs using chemical method. Silver nitrate, gelatin, glucose and sodium hydroxide are used as silver precursor, stabilizer, reducing agent and accelerator reagent, respectively. Format...

Silver nanoparticles (Ag-NPs) were successfully synthesized in the natural polymeric matrix. Here we report on the effect of NaOH in preparing polymer synthesis of Ag-NPs using chemical method. Silver nitrate, gelatin, glucose and sodium hydroxide are used as silver precursor, stabilizer, reducing agent and accelerator reagent, respectively. Format...

The synthesis of the stable copper nanoparticles is more difficult because copper nanoparticles are easily oxidized. Synthesis procedure, including chemical reduction with isopropyl alcohol along cetyltrimethyl ammonium bromide(CTAB). Stability of the copper NPs depend on reagent concentrations, relative amounts of reactants and temperature. PL spe...