Research Project 1

Development and application of nanomaterials in environmental protection

(Ray, Hamme, Hossain, Yu, Leszczynski, Hill, Liu, Leszczynska)

Environmental pollution by pathogenic bacteria and chemical toxins has been a major concern of today's society. Water pollution caused by biological and chemical toxins like Salmonella, E-coli, arsenic, mercury and lead is a serious problem due to the potential for contracting diseases from pathogens. Recently, we have reported several nanomaterial-based techniques for the selective detection of toxic metals and pathogenic bacteria. It is highly selective and capable of differentiating pathogen strains and as a result, reduces false positives.

The Creation, Control, and Monitoring Shape Evaluation of Nanostructures: Many challenges remain in the control of single molecules and their environments to create precise nanomaterials. Scientists need to achieve very high control over the size, shape, and surface properties of nanocrystals, which is necessary for understanding the potential of remarkable nanomaterials. Though there is a lot of progress over the past decade on the synthesis of nanomaterials of various sizes and shapes with different properties, an important challenge is that there is no acceptable mechanism to explain how size and shape control works. As a result, our objective of this project is to design, control and understand how shape evaluation works. Our aim is to understand the initial nucleation, growth, and shape evolution for different shapes of branched nanostructures of metals and semiconductors. The REU students will be involved in the synthesis and monitoring of the mechanism of controlled growth of sizes and shapes of different gold nanoparticles.

Gold Nanoparticle-Based Colorimetric Assay for Selective Detection of Toxic Metal ions from Paints, Toys and Environmental Samples: Toxic heavy metals like Pb (II), Hg(II) and Cd(II) are very common environmental pollutants with high toxicity. These metals are routinely released from coal-burning power plants, volcanic emissions, gold mining, and solid waste incineration. The goals of the project are: a) to develop gold nanoparticle-based colorimetric assay for ultrasensitive detection of toxic metals from environmental samples selectively and simultaneously, and b) to understand fundamentals of the interaction between toxic metals and nanoparticle surface. Our aim is to investigate how the assay sensitivity and mechanism varies with particle sizes from 1 – 100 nm and particle shapes (spheres, rods and prisms). The REU students will be involved in synthesis and characterization of gold nanoparticles of different sizes and shapes, surface modifications, and finding its use as optical sensors for toxic metals in environmental samples.

Gold Nanomaterial-Based Sensing of Biological Toxins from Food Samples: Water and food pollution caused by food pathogen contamination is a serious problem in the world. Very often, concentrations of pathogens in food contamination are very small and on the other hand, the number of different possible pathogens is high. As a result, it is not easy to test pathogens in every food sample collected. The goal of this project is to develop gold-nanoparticle based absorption spectroscopy assay for ultrasensitive and highly selective detection of pathogens in water and food samples. The REU students will be involved in synthesis and characterization of different gold nanoparticles, surface modifications with antibodies, and finding its use as plasmon sensors for pathogens.

Sensing of anions with polyamide-attached gold nanoparticles: This supramolecular chemistry research project will focus on molecular sensors for the detection of anions of environmental and biological relevance. In this project, the plan is to focus on common inorganic anions, halides, pseudohalides, and oxoanions which are known pollutants in the environment. The aim is to use polyamide attached gold nanoparticle for selective sensing. The REU students will be involved in synthesis and characterization of polyamide macromolecules, modification of gold nanoparticles, and finding its use as optical sensors for various anions.

Magnetic core gold shell nanoparticles for separation of biological toxin: Though we are advancing the water treatment processes with time, outbreaks due to the contamination of waterborne bacteria like pathogenic Escherichia coli, Salmonella and Shigella are quite common in the U.S. and other countries. Recent data show that even in the U.S. alone, $20 billion per year of economic productivity is lost due to water contamination by waterborne pathogens. Our aim is to utilize antibody coated gold shell magnetic core nanoparticles for rapid, inexpensive, and effective capture and removal of bacterial pathogens from water sample. REU students will be involved in synthesis and characterization of magnetic core-gold shell nanoparticles, surface modifications with antibodies, and finding its use for pathogens detection and separations.

SWCNT/AuNP hybrid nanomaterial based filter for water purification: Due to the presence of huge number of biological and chemical toxins, it is a real challenge to prevent waterborne pathogen and chemical toxin outbreaks. On the other hand, to protect public health, this challenge must be met. Recently, it has been reported that nanotechnology based filter can be used for water purification. Our aim is to develop and characterize single-walled carbon nanotubes (SWCNT)/gold nanoparticle (AuNP) hybrid material based filter for the removal of bacteria and chemical toxins like Hg(II), Pb2+, and As3+ from water. The REU students will be involved in developing and characterizing hybrid materials and finding the use of these materials as filters for water purification from biological contaminations.

Theoretical Modeling of nano-bio interaction: In this project, theoretical and numerical studies will be used to describe optical properties of metal nanoparticles with biomolecular adsorbates that are relevant for biosensing. The project will include microscopic calculations of fluorescence quenching efficiency for various fluorephores adsorbed on nanoparticles of various sizes and shapes, energy transfer processes between donor and acceptor molecules adsorbed at metal surface, and accurate calculations of radiative lifetimes for large numbers of fluorophores attached to a nanoparticle. The calculations will be carried out using time-dependent density-functional theory methods as well as electromagnetic calculations. The REU students will be involved in performing density-functional calculations for study of nano-bio interactions.