Browsing by Author "Lawrence, Katie"

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    Label-Free Nanoplasmonic-Based Short Noncoding RNA Sensing at Attomolar Concentrations Allows for Quantitative and Highly Specific Assay of MicroRNA-10b in Biological Fluids and Circulating Exosomes
    (American Chemical Society, 2015-11-24) Joshi, Gayatri K.; Deitz-McElyea, Samantha; Liyanage, Thakshila; Lawrence, Katie; Mali, Sonali; Sardar, Rajesh; Korc, Murray; Department of Medicine, IU School of Medicine
    MicroRNAs are short noncoding RNAs consisting of 18-25 nucleotides that target specific mRNA moieties for translational repression or degradation, thereby modulating numerous biological processes. Although microRNAs have the ability to behave like oncogenes or tumor suppressors in a cell-autonomous manner, their exact roles following release into the circulation are only now being unraveled and it is important to establish sensitive assays to measure their levels in different compartments in the circulation. Here, an ultrasensitive localized surface plasmon resonance (LSPR)-based microRNA sensor with single nucleotide specificity was developed using chemically synthesized gold nanoprisms attached onto a solid substrate with unprecedented long-term stability and reversibility. The sensor was used to specifically detect microRNA-10b at the attomolar (10(-18) M) concentration in pancreatic cancer cell lines, derived tissue culture media, human plasma, and media and plasma exosomes. In addition, for the first time, our label-free and nondestructive sensing technique was used to quantify microRNA-10b in highly purified exosomes isolated from patients with pancreatic cancer or chronic pancreatitis, and from normal controls. We show that microRNA-10b levels were significantly higher in plasma-derived exosomes from pancreatic ductal adenocarcinoma patients when compared with patients with chronic pancreatitis or normal controls. Our findings suggest that this unique technique can be used to design novel diagnostic strategies for pancreatic and other cancers based on the direct quantitative measurement of plasma and exosome microRNAs, and can be readily extended to other diseases with identifiable microRNA signatures.
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    Unique Design of CuInSe2 Nanocrystal decorated Gold Nanoprism Hybrid Conjugates for Advanced Photocatalytic Application
    (Office of the Vice Chancellor for Research, 2015-04-17) Lawrence, Katie; Jana, Atanu; Liyanage, Thakshila; Sardar, Rajesh
    We present CuInSe2 nanocrystal decorated gold nanoprism hybrid conjugates with advanced photocatalytic ability in order to offer a unique and environmentally sound solution to the current obstacles faced by photovoltaic device materials currently used. A search for clean and abundant energy sources is a major concern for the environmentally conscious scientist. Photocatalytic reactions can harness this energy and use it for a variety of applications including oxidation of organic contaminants, self-cleaning glass, conversion to water as hydrogen glass, and decomposition of crude oil. However solar absorption in these devices is lacking the efficiency needed to be cost effective. Choice of device material is pivotal in overcoming this large hurdle. Materials such as TiO2, the most commonly used semiconductor photocatalyst, for example only absorbs light in the ultraviolet region which accounts for less than 5% of total solar radiation. Hybrid conjugates, or nanomaterials combining semiconductor and metal materials, are a fast growing alternative to this problem. By incorporating localized surface plasmon resonance (LSPR) properties of the metal nanostructures with controllable band gaps of the semiconductor nanocrystals, the material can shift to the visible and near-infrared spectra thus allowing for greater solar absorbance. However, to the best of our knowledge, no reports are available in which plasmonic coupling occurs between a LSPR active metal nanostructures and the tailoring of the semiconductor nanocrystals’ band gap by a non-toxic, low temperature synthesis. Hybrid conjugates between LSPR active metal nanostructures and semiconductor nanostructures have been reported but suffer from cost effectiveness and often use environmentally unfriendly chemicals. We believe our unique hybrid nanomaterial will allow for further tuning of the LSPR peak position in order to extend light absorption to a more optimal window and further excite electron-hole pairs in order to provide the most photocatalytic activity to date while providing an environmentally friendly and cost-effective approach. This work has major implications in clean energy and more specifically the advancement of photocatalytic applications.