Kousik Sivakumar

Single-wall carbon nanotube nanobomb agents for killing breast cancer cells

We report the first application of single-wall carbon nanotubes (SWCNT) as potent therapeutic nanobomb agents for killing breast cancer cells. We show here that by adsorbing water molecules in SWCNT sheets or loosely adsorbed on top of cells, potent nanobombs were created that heated the water molecules inside them to more than 100°C upon exposure to laser light of 800 nm at light intensities of approx 50–200 mW/cm2. Conversion of optical energy into thermal energy, and the subsequent confinement of thermal energy in SWCNT, caused the water molecules to evaporate and develop extreme pressures in SWCNT causing them to explode in solutions. Co-localized nanobombs killed human BT474 breast cancer cells in physiological phosphate-buffered saline (PBS) solution. Cells that were treated with nanobombs exploded into fragments, while the surrounding cells not treated with nanobombs were viable. SWCNT-based nanobomb agents can potentially outperform most nanotechnological approaches in killing cancer cells without toxicity.

Applications of carbon nanotubes for cancer research

Carbon nanotubes have many unique properties such as high surface area, hollow cavities, and excellent mechanical and electrical properties. Interfacing carbon nanotubes with biological systems could lead to significant applications in various disease diagnoses. Significant progress in interfacing carbon nanotubes with biological materials has been made in key areas such as aqueous solubility, chemical and biological functionalization for biocompatibility and specificity, and electronic sensing of proteins. In addition, the bioconjugated nanotubes combined with the sensitive nanotube-based electronic devices would enable sensitive biosensors toward medical diagnostics. Furthermore, recent findings of improved cell membrane permeability for carbon nanotubes would also expand medical applications to therapeutics using carbon nanotubes as carriers in gene delivery systems. This article reviews the current trends in biological functionalization of carbon nanotubes and their potential applications for breast cancer diagnostics. The article also reports the applications of confocal microscopy for use in understanding the interactions of biological materials such as antibodies on carbon nanotubes that are specific to surface receptors in breast cancer cells. Furthermore, a nanotube-field-effect transistor is demonstrated for electronic sensing of antibodies that are specific to surface receptors in cancer cells.

Surface Oriented Self Assembled Growth of Carbon Nanotubes

We report the self assembled surface oriented growth of single walled carbon nanotubes along the surface of

Surface Oriented Self-Assembly of Carbon Nanotubes

In this paper, we demonstrate the self assembled growth of nanotubes along the surface of (100), (110) and (111) silicon wafers using thermal CVD. Iron nanoparticles, 10 nm in diameter, were used as the catalyst. Carbon nanotubes were grown in a methane atmosphere at 1000°C. SEM and AFM characterization revealed single wall carbon nanotubes, about 10 nm in diameter and up to 10 νm in length, growing along the direction of the silicon wafer. The mechanism of growth of nanotubes is similar to that of molecular epitaxy which occurs due to the lattice matching of the silicon and iron crystal lattices forming self aligned silicides at high temperature which help orient the nanotubes. This process may enable the integration of nanotubes with CMOS processing technology.

Electric field assisted deposition of nanowires from carbon nanotubes for nanoelectronics and sensor applications

Manipulation and control of matter at the nano- and atomic level are crucial for the success of nano-scale sensors and actuators. The ability to control and synthesize multilayer structures using carbon nanotubes that will enable to build electronic devices within a nanotube is still in its infancy. In this paper, we present results on selective electric field assisted deposition of metals on carbon nanotubes realizing metallic nanowire structures. Silver and platinum nanowires has been fabricated using this approach due to its applications in chemical sensing as catalytic materials to sniff toxic agents and in the area of biomedical nanotechnology for construction of artificial muscles. The electric field assisted deposition allows the deposition of metals with high degree of selectivity on carbon nanotubes by manipulating the charges on the surface of the nanotubes. SEM and TEM investigations revealed silver and platinum nanowires between 10 nm-100 nm in diameter. The present technique is versatile and enables the fabrication of host of different types of metallic and semiconducting nanowires using carbon nanotube templates for nanoelectronics and myriad of sensor applications. Further, nanowires can also serve as model systems for studying quantum size effects at these dimensions.

Metallic Nanowires From Carbon Nanotube Building Blocks: The Effect of Atomic Defects on the Nanotube Influencing Nanowire Growth

Manipulation and control of matter at the nano- and atomic level are crucial for the success of nano-scale sensors and actuators. The ability to control and synthesize multilayer structures using carbon nanotubes that will enable to build electronic devices within a nanotube is still in its infancy. In this paper, we present results on selective electric field assisted deposition of metals on carbon nanotubes realizing metallic nanowire structures. Silver and platinum nanowires has been fabricated using this approach due to its applications in chemical sensing sensing as catalytic materials to sniff toxic agents and in the area of biomedical nanotechnology for construction of artificial muscles. The electric field assisted technique allows the deposition of metals with high degree of selectivity on carbon nanotubes by manipulating the charges on the surface of the nanotubes. The thickness and the growth of the nanowires was altered by inducing defects on the initial surface of the nanotubes that affected the local current densities and electrochemical reduction of silver and platinum on those defect sites. SEM and TEM investigations revealed silver and platinum nanowires between 10 nm-100 nm in diameter. Relatively higher metal deposition was achieved in defect related sites or places where the nanotubes criss-crossed each other, due to the high current densities in these sites. The present technique is versatile and enables the fabrication of host of different types of metallic and semiconduting nanowires using carbon nanotube templates for nanoelectronics and myriad of sensor applications. Further, nanowires can also serve as model systems for studying quantum size effects in these dimensions.Copyright