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Title: Design and calibration of optical tweezers for single-molecule studies
Authors: Yeh, Richard Cheng-I
Keywords: optical tweezers
DNA stretching
optical trap
Issue Date: Jan-2002
Publisher: Cornell University
Citation: Yeh, Richard Cheng-I. Master's thesis, Cornell University, 2002.
Abstract: Feedback-controlled optical tweezers are used to manipulate single biological molecules in experiments on deoxyribonucleic acid (DNA) substrates. Before we trust these measurements, it is essential to know the accuracy and the precision of the device. This thesis describes the design and calibration of the optical tweezers. We measure relative displacements with nanometer accuracy and forces with an accuracy of 10%. The chief source of imprecision is in the human positioning of the sample under study. The capability of the instrument is demonstrated by stretching single molecules of DNA because of the elasticity of DNA has previously been well characterized. This thesis also compares DNA elasticity measurements made on this device with previously published data. I demonstrate that this instrument is well suited for characterizing DNA molecules that are long (~ 4000 bp), but not for DNA that are relatively short (~ 1000 bp). Fit parameters for new DNA tethers containing 4400 base pairs (bp) of DNA agree with expected values. The optical tweezers instrument is accurate enough to determine that one-hour-old 4400-bp DNA tethers have degraded, losing some 4% of their length. Our current methods are not appropriate for measurements of force-extension of short DNA molecules, such as 1155-bp DNA tethers.
Description: This version is a PDF produced from the source Microsoft Word document. Figure 13, on logical page 36 (PDF page 46), is missing. It was a CorelDraw drawing of the optical layout. Please see the supplemental files "20000710 tweezers1xx AI9.emf" and "20000710 tweezers1xx" for enhanced metafile and Adobe Illustrator 9 versions of that figure.
Appears in Collections:Cornell Theses and Dissertations

Files in This Item:

File Description SizeFormat
020116_Thesis_Final_attachedFig13.pdfThesis document619.59 kBAdobe PDFView/Open
20000710 tweezers1xx AI9.emfFigure 13 (optical layout) in enhanced metafile format65.75 kBWMF ImageView/Open
20000710 tweezers1xx AI9.aiFigure 13 (optical layout) in Adobe Illustrator (9) format85.29 kBPostscriptView/Open

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