Abstract/Details

Optical and MR molecular imaging probes and peptide-based cellular delivery for RNA detection in living cells


2005 2005

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Abstract (summary)

Detection, imaging and quantification of gene expression in living cells can provide essential information on basic biological issues and disease processes. To establish this technology, we need to develop molecular probes and cellular delivery methods to detect specific RNAs in live cells with potential for in vivo applications. In this thesis work, the major focus is placed on the development of molecular beacons and biochemical approaches (peptides etc.) to deliver such probes to different cellular compartments. These approaches are then employed to study the expression and localization of mRNAs, co-localization of mRNAs with cytoplasmic organelles and cytoskeleton, and co-localization of RNA molecules in the nuclei of living cells.

Further along this direction, we were interested in developing a better understanding of the functional states of mRNAs and the fluorescent signal observed in optical imaging experiments. To achieve this goal, we altered the translational process and studied its effect on the detection of mRNAs in living cells. The results of these studies indicate that the translational state of mRNAs favors the hybridization of molecular beacon with its target sequence. This study has also provided the evidence that molecular beacons are reversibly bound to target mRNAs and the repression of the translational process can prevent molecular beacon from binding to its target mRNA. Further, using these approaches in combination with FRAP based biophysical analysis, the dynamics of endogenous RNA in living cells are studied. These studies revealed the possible subcellular organization of RNA molecules and their dynamics in living cells. The results also demonstrated the role of cytoskeleton and ATP in the mobility of specific mRNAs in the cytoplasm.

In addition to optical probes, studies have been carried out to develop an MRI contrast agent using iron-oxide nanoparticles for deep tissue molecular imaging. Specifically, we have functionalized magnetic nanoparticles that are water-soluble, mono-dispersed, biocompatible, and easily adaptable for multifunctional bioconjugation of probes and ligands. We have successfully delivered magnetic nanoparticle bioconjugates into live cells and demonstrated their effect on relaxivity. We have further studied the role of coating thickness for optimization of contrast and further enhance the fundamental understanding of contrast mechanisms.

Indexing (details)


Subject
Biomedical research
Classification
0541: Biomedical research
Identifier / keyword
Applied sciences; Cellular delivery; Molecular imaging probes; RNA detection
Title
Optical and MR molecular imaging probes and peptide-based cellular delivery for RNA detection in living cells
Author
Nitin, Nitin
Number of pages
275
Publication year
2005
Degree date
2005
School code
0078
Source
DAI-B 66/11, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780542434044, 0542434040
Advisor
Bao, Gang
University/institution
Georgia Institute of Technology
University location
United States -- Georgia
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3198582
ProQuest document ID
304999940
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304999940
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