Sunil Kumar Sailapu

Induction of Electromotive Force by an Autonomously Moving Magnetic Bot

We report the observation of the induction of electromotive force (emf) into a Faraday coil by an autonomously moving composite magnetic particle in aqueous medium. The particle consisted of a micron-sized polymer sphere, which was decorated with catalytic Pd nanoparticles (NPs) and attached to a micron-scale (N-42 grade) rare-earth magnet. The Pd NPs catalytically decomposed H2 O2 to generate O2 , resulting in buoyancy-driven vertical motion of the particle, while the micromagnet induced emf during the flight. Because a small volume of ethanol was layered on top of the liquid, the bubble burst when the particle ascended to the top and thus nearly continuous vertical motion was achieved. Spikes of alternating electrical signal could be observed up to 20 times per minute. The signal was sufficiently strong to illuminate light-emitting diodes following appropriate amplification. This distinctive approach is expected to pave the way to developing synthetic bots which are autonomously propelled, generating their own signal for running complex circuitry.

Hierarchical Logic Structures Based on Responsive Fluorescent Gold Nanoclusters

Logic with Gold Clusters. Gold nanoclusters can be used for the development of hierarchical logic structures. This is based on the reversible change in the fluorescence of the clusters at different pH of the medium, its temperature and metal ion concentration dependence.

Luminescent carbon dots for logic operations in two phases.

Basic and higher integrated logic operations have been achieved by using luminescent carbon dots through interactions with metal ions and organic molecules in liquid dispersions as well as in the solid phase. The biphasic simple and complex logic systems could be potentially used for various analytical applications as well as for the detection of important elements in diverse environments.

Single Platform for Gene and Protein Expression Analyses Using Luminescent Gold Nanoclusters

A single platform for gene and protein expression studies is proposed to pursue rapid diagnostics. A common method to synthesize gold (Au) nanoclusters on both DNA and protein template was developed using a benchtop device. The method of synthesis is rapid and versatile and can be applied to different classes of DNA/protein. Employing luminescent Au nanoclusters as the signal-generating agents, the device enables carrying out reverse transcriptase polymerase chain reaction and array-based analyses of multiple genes/proteins simultaneously using switchable holders and custom-designed software. The device and methods were applied to evaluate gene profiling related to apoptosis in HeLa cancer cells and further to analyze the protein expressions of glutathione-S-transferase (GST) and GST-tagged human granulocyte macrophage colony-stimulating factor (GST-hGMCSF) recombinant proteins purified from bacterial strains of BL21(DE3) Escherichia coli (E. coli). The device with user-friendly methods for diagnosis using the luminescence of Au nanoclusters offers potential use in disease diagnostics with a vision to extend health care facilities especially to remote geographical locations.

Phenylboronic Acid Templated Gold Nanoclusters for Mucin Detection Using a Smartphone-Based Device and Targeted Cancer Cell Theranostics

A phenylboronic acid templated gold nanocluster probe was developed to detect biomarker mucin by a noninvasive fluorescence-based method using a point-of-care smartphone-based fluorescence detection device. The gold nanocluster probe is able to detect mucin specifically. The same probe was applied for in vitro targeted bioimaging of HeLa and Hep G2 cancer cells, and it demonstrated specific therapeutic effects toward cancer cells as well as multicellular tumor spheroids imparting theranostic properties. The module is found to be more effective toward HeLa cells, and a pathway of cell death was established using flow-cytometry-based assays.