Source: SOUTH CAROLINA STATE UNIVERSITY submitted to NRP
QUANTUM DOT SENSORS FOR DETECTION OF UNUSUAL DNA STRUCTURES ASSOCIATED WITH HUMAN DISEASES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
0216810
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jan 14, 2009
Project End Date
Jul 31, 2012
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
SOUTH CAROLINA STATE UNIVERSITY
(N/A)
ORANGEBURG,SC 29117
Performing Department
Engineering Technologies
Non Technical Summary
In South Carolina, African Americans represent 30% of the state's population whereas all other minority groups combined total 1%. SCSU is an HBCU with a 93% African American student population. The broader impacts of this work are closely tied to its goals, which are to advance undergraduate research for underrepresented minorities and women, while promoting teaching, training and learning. The work will largely be performed by research associate and undergraduate students at SCSU, which is an excellent means to build up the science and technology workforce of the future - especially in a state like South Carolina, which aspires to participate in the "knowledge economy" but whose current major industries are tourism, agriculture, and manufacturing. Seminar presentations will be arranged to increase general public awareness, and knowledge about the neurodegenerative diseases. This project includes nurturing of a chemistry culture at SCSU that will include participation at local and national chemistry society meetings (poster and oral presentations), and improvement of the SCSU research infrastructure. Existing ties between SCSU and USC will be strengthened by this collaborative work, and access to and use of state of the art research equipment at USC by SCSU researchers will be expanded further. This work will also provide a highly multidisciplinary environment for students. The creation of cutting edge research opportunities, coupled with extensive mentoring, will create a research environment conductive to attracting underrepresented minorities and women, and to guiding them towards scientific careers and higher education. "The 1890 Research and Extension Program works to build collaborations": Existing ties between SCSU and USC will be strengthened by this collaborative work, and access to and use of state of the art research equipment at USC by SCSU researchers will be expanded further. The creation of cutting edge research opportunities, coupled with extensive mentoring, will create a research environment conductive to attracting underrepresented minorities and women, and to guiding them towards scientific careers and higher education. "The 1890 Evans Allen Research Mission is to build the research development capacity at the University": This project will provide an excellent opportunity for minority students to participate in undergraduate research at SCSU under the guidance of Dr. Mahtab. The creation of cutting edge research opportunities, coupled with extensive mentoring, will create a research environment conductive to attracting underrepresented minorities and women, and to guiding them towards scientific careers and higher education. "The 1890 Cooperative Extension mission is to build the land-grant public service outreach capacity of the University by providing specific educational and effective informational delivery services directly---to communities": Findings from research will be sent as bulletins to the Extension Offices for distribution to their clientele. Seminar presentations will be arranged to educate the public and to increase general awareness, and knowledge about the neurodegenerative diseases.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
70270101000100%
Goals / Objectives
The goal of this project is to develop nanomaterial based sensors of unusual non-B form DNA structures, with emphasis on DNA sequences that are implicated in human neurodegenerative diseases. Novel methods for the detection of DNA are highly desirable for genetic defect detection. Many, if not most, diseases have their roots in our genes. More than 4,000 diseases are thought to stem from mutated genes inherited from one's mother and/or father. Human neurodegenerative diseases such as Fragile X syndrome, Huntington's disease, Mytonic Dystrophy, and Alzheimer disease, to name a few, has been traced to genetic mutations. A particularly interesting and rapidly expanding area of nanoscience and nanotechnology involves research in which inorganic materials and biological molecules converge. Our work will be focused on developing inorganic nanomaterials as optical probes of disease related non-B DNA conformations, and, on studying how modifications of the surfaces of these nanomaterials affect their functionality for sensing sequence directed DNA structures. The colloidal inorganic nanoparticles of our choice will be cadmium sulfide (CdS). These nanomaterials emit visible light when irradiated, and this photoluminescence is sensitive to the nature and amount of adsorbate bound to the particle surface. The nanoparticles can simulate, in terms of size and surface group, a protein-like surface, with the added benefit of a spectroscopic handle to assess DNA-particle interactions. Ultimately, we may be able to design nanoparticles that bind to specific DNA sequences based on the principles that we discover based on our results. These studies will also provide insight into the physical nature of the DNA wrapping process. Long-term potential applications of this research at the DNA-nanomaterial interface include the development of nanoparticles as optical DNA diagnostics, nanoparticle DNA delivery agents, and a more thorough understanding of the operating parameters for DNA-based nanodevices.
Project Methods
Our nanoparticle of choice will be cadmium sulfide nanoparticles with different surface modifications.The usual method of making CdS nanoclusters (diameter 1-20 nm) is an arrested precipitation reaction, in which a Cd(II) salt and a sulfide source are mixed, usually in aqueous solution, in the presence of a stabilizing agent, which most typically is a polymer. In all these methods the stabilizer defines the dimensions of the reaction space to some extent and thus cluster size. "Activation" of nanoparticles by the subsequent addition of metal nitrate salt at basic pH produces nanoparticles that have a nominal M(II)-OH coat. We will also cap CdS particles with cations other than Cd2+, e.g. K+ as the monovalent, and the more biologically relevant Zn2+, metal ion. We would also cap our CdS particles with peptides to further simulate a protein surface. The surface charge of the peptide-coated CdS nanoparticles can be tuned by pH. The nanoparticles will be characterized by UV-Vis spectroscopy, photoluminescence and transmission electron microscopy. Measurement of the nanoparticle effective charge (zeta potential) is an important new experiment to be performed. To date, more than 12 human genetic diseases including myotonic dystrophy, fragile X syndrome, Huntington disease, several spinocerebellar ataxias, and Friedreich ataxia, have been associated with the expansion of CTG, CGG, or GAA repeats. We are particularly interested in studying the left-handed Z-DNA, the cruciform, the tetraplex, the triplex, and the slipped (hairpin) structure forming DNA sequences. Standard oligonucleotides are commercially available from suppliers such as Midland Certified Reagents, MWG Biotech, or Operon. Methods: Our primary method of assessing DNA binding about our substrates is photoluminescence titration experiments, in which the photoluminescence is from the substrate. Comparison of the relative binding constants of the oligonuclides will give us a better understanding of DNA-nanoparticle interaction. The ability of DNA to flex and fold about a protein is key to the physical understanding of DNA functions. In the proposed work, we shall expand our investigation by:(i)varying the nanoparticles by modifications of the surface with more biologically relevant cations, thiols and peptides; (ii)examining DNA sequences with higher order structures and sequences that are implicated in human diseases; (iii)studying the kinetics of the DNA-nanoparticle interactions. (iv)measureing nanoparticle zeta potential and degree of aggregation upon DNA binding. The nanoparticles may function as new reagents to detect anomalous DNA. The ability of DNA to flex and fold about a protein is key to the physical understanding of DNA functions. The work described in this proposal will lead to a better understanding of how the sequence directed structure and/or flexibility of DNA influence its binding to a protein-sized (inorganic) substrate. These results would be of interest to the inorganic nanoparticle community and to the nucleic acid biophysical chemists. The work will also provide a highly multidisciplinary environment for the students.

Progress 01/14/09 to 07/31/12

Outputs
OUTPUTS: Under the supervision of Dr. Rahina Mahtab, five undergraduate research students and one graduate research assistant participated in the research project. The research was productive, resulting in the development of quantum dot bio-sensors with demonstrated capabilities of selectively sensing the unusual DNA structures implicated in a number of neurodegenerative diseases, as well as a normal double stranded DNA sequence. The quantum dots were synthesized by Arrested Precipitation technique, by the reaction of cadmium nitrite with sodium sulfide in presence of sodium polyphosphate at a pH of 10.3. The synthesized quantum dots were surface activated with zinc, magnesium and cadmium cations. All quantum dots were characterized by UV absorption spectroscopy and by Transmission Electron Microscopy (TEM) for size. The DNA structures selected, because of their relation to neurodegenerative diseases, were stem looped, cruciform, and tetraplex DNAs. Disorders Caused by Stem-Looped DNA: Schizophrenia, Cornelia de Lange Syndrome, FG Syndrome. Disorders Caused by Cruciform DNA: Bloom's Syndrome, Werner's Syndrome, Fanconi Anemia (FA) Disorders Caused by Tetraplex DNA: Huntington's Disease, Mytonic Dystropy, Fragile X Syndrome. PARTICIPANTS: PI Dr. Rahina Mahtab-; Research Assistant Ms. April Pearson-Wright-; Undergraduate Research Students -- Ms. Andrea Payne, Ms. Nisha Glasgow, Ms. Arielle Orridge, Mr. Faheeem H. Muhammad, Mr. Adisa M. M. Julien. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Invited lecture on 1890 Research work delivered at international research conference. The PI, Dr. Rahina Mahtab, was invited to and gave a lecture on her research at the 34th Annual Conference of the Bangladesh Chemical Society held in Dhaka, Bangladesh, on December 19, 2011. Research poster was presented at the Undergraduate STEM and Behavioral Science Research Symposium held at Claflin University, Orangeburg, South Carolina on March 23, 2012. The poster was awarded third place. An informative poster including research findings on neurodegenerative diseases was developed for general public.

Publications

  • No publications reported this period


Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: Mahtab's guidance by three undergraduate research students and one research assistant. The research was very productive resulting in the development of quantum dot biosensors with demonstrated capabilities of selectively sensing the unusual DNA structures implicated in a number of neurodegenerative diseases, as well as a normal double stranded DNA sequence. The quantum dots were synthesized by the "Arrested Precipitation" technique by the reaction of cadmium nitrite with sodium sulfide in the presence of sodium polyphosphate at a pH of 10.3. The synthesized quantum dots were then characterized by UV absorption spectroscopy and by Transmission Electron Microscopy (TEM) for size. The protein-sized (~5nm) colloidal semiconductor nanomaterials (inactivated) biosensors were then surface-activated with positively charged ions so that they could interact with the overall negatively charged surface of the targeted DNA molecules. The activated quantum dots were (i) cadmium sulfide quantum dots surface activated with Cd2+ ions; (ii) cadmium sulfide quantum dots surface-activated with Zn2+ ions; and (iii) cadmium sulfide quantum dots surface-activated with Mg2+ ions. The size and surface charges of the synthesized quantum dots were also verified by data from the Zeta-Potential Analyzer. Each of these surface-activated quantum dots were followed by fluorescence spectroscopy to ensure that maximum photoluminescence was achieved. These quantum dots sensors are very luminescent (Fig.3); this photoluminescence is extremely sensitive to what is on the surface and as demonstrated by our work, highly selective to its surroundings, making these ideal for selective targeting. The DNA structures were selected because of their relation to neurodegenerative diseases, to stem-looped, to cruciform, and to tetraplex DNAs. For example, disorders caused by stem-looped DNA include the following: Schizophrenia, Cornelia de Lange syndrome, and FG syndrome; disorders caused by cruciform DNA include the following: Bloom's Syndrome, Werner's syndrome, and Fanconi Anemia (FA); and disorders caused by Tetraplex DNA include the following: Huntington's disease, Mytonic Dystropy, and Fragile X Syndrome. Spectroscopic titrations were performed for each of the DNA sequences with the surface-activated quantum dots. The quenching of the quantum dot fluorescence by interactions with the DNAs was followed by emission spectroscopy. As is evident from the titration data whether the nanomaterials are surface-activated with cadmium, zinc, or magnesium ions, each of the surface-activated quantum dots can differentiate between the normal, the stem-looped, the cruciform, and the tetraplex DNAs. It is also evident from the experimental data, that of the three different surface activated quantum dots, the Cd2+ activated nanomaterials are more efficient as sensors than either the Mg2+, or the Zn2+ activated quantum dots. These are exciting data. More work is ongoing in our lab towards calculating the binding constant data. PARTICIPANTS: Dr. Rahina Mahtab-PI; Ms. April Pearson-Wright- Research Assistant; Ms. Arielle Orridge-Undergraduate Research Student; Mr. Faheeem H. Muhammad- Undergraduate Research Student; Mr. Adisa M. M. Julien- Undergraduate Research Student TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The quality of the research work in Dr. Mahtab's lab has always attracted top quality students. One of these research students, Ms. Andrea Payne who graduated in May 2011, was recognized and awarded the Outstanding Undergraduate Chemistry Award presented by the South Carolina Section of the American Chemical Society in April 2011. Ms. Payne was accepted last fall at Ohio State University by their Ph. D. program in Chemistry. Another research student currently working in Dr. Mahtab's 1890 Research group, Ms. Arielle Orridge, will be recognized by the South Carolina Section of the American Chemical Society as the Outstanding Chemistry Undergraduate at an award ceremony next month to be held at Claflin University. Ms. Orridge will also present a poster on her 1890 research work on that day. Ms. Orridge, who is graduating in May 2012, has already been accepted for Graduate studies by two universities, the South Carolina College of Pharmacy-MUSC campus, as well as the Mercer University College of Pharmacy and Health Sciences. Presentation at the international conference showcased research results/activities to a global audience. Informative and research poster/findings will heighten awareness for our fantastic research in the community and far beyond. These will also contribute towards increasing community/public awareness and knowledge of the various aspects of dealing with neurodegenerative diseases.

Publications

  • No publications reported this period


Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Two undergraduate students and a graduate (MS) research assistant was hired and worked on this project. The required chemical and supplies were procured. The bidding process for the Zeta Potential equipment was completed, and the equipment was purchased. PARTICIPANTS: The folowing individuals worked on the project: Dr. Rahina Mahtab-PI; Ms. April Pearson-Wright,Research Assistant; Ms. Arielle Orridge,Undergraduate Research Student; Ms. Nisha Glasgow, Undergraduate Research Student. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Synthetic procedures of protein sized colloidal semiconductor quantum dots were successfully established. The quantum dots were fully characterized for size by UV-Vis, emission, and transmission electron microscope studies. Effects of surface coating of the nanomaterials with various cations were studied. The surfaces of the quantum dots were successfully coated with cadmium 2+, zinc 2+ and potassium 1+ cations. Coating with the cadmium and zinc cations resulted in an increase of quantum dot luminescence while coating with potassium ions did not increase the luminescence of the quantum dots. In order to compare the effect of charged ions with that of neutral molecules on the surface, the quantum dots were next coated with the neutral molecule mercaptoethanol, and experiments on this are still ongoing. Oligonucleotides with sequences associated human neurodegenerative diseases have been custom synthesized. The synthesized DNAs are now being purified using High Performance Liquid Chromatography (HPLC). Students have successfully carried out nanoscale synthetic procedures, as well as surface activations. At this time, they are fully trained and can independently use the various spectrophotometers and interpret the data obtained. The students have gained valuable experience to make them competitive for graduate school admission.

Publications

  • No publications reported this period


Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: An acquisition of a Zeta Potential Particle Size Analyzer equipment was submitted. Measurement of nanoparticle effective charge (zeta potential) is critical for the DNA binding studies. The Zeta Potential Particle Size Analyzer equipment is essential for the measurement of the zeta potential of nanoparticles, which is an important new experiment to be performed in this project. The two undergraduate research assistants have started work on the project. They have trained on the use of UV-Vis spectrophotometer, pH meter, water purifier, and the Fluorimeter, and weight measurements for nanoscale syntheses. Experiments have been performed to synthesize colloidal semiconductor nanomaterials (CdS) in aqueous solution.Absorption spectra of these samples were recorded. PARTICIPANTS: The PI on the project is Dr. Rahina Mahtab, Professor, Department of Biological & Physical Sciences. Two undergraduate students have been hired to work on the project: Ms. Andrea D. Payne, senior chemistry major, and Ms. Arielle S. Orridge, sophomore chemistry major, are now working on the project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
In South Carolina, African Americans represent 30% of the state's population whereas all other minority groups combined total 1%. SCSU is an HBCU with a 93% African American student population. The broader impacts of this work are closely tied to its goals, which are to advance undergraduate research for underrepresented minorities and women, while promoting teaching, training and learning. The work will largely be performed by research associate and undergraduate students at SCSU, which is an excellent means to build up the science and technology workforce of the future - especially in a state like South Carolina, which aspires to participate in the "knowledge economy" but whose current major industries are tourism, agriculture, and manufacturing.

Publications

  • No publications reported this period