New York University

Other

Columbia University

Rastislav Levicky

Kenneth Shepard

Ping Gong

Napoleon Tercero

Yatao Liu

George Patounakis

Kang Wong

Wanqiong Qiao

Kang Wang

Provided are methods and devices for detection of unlabeled nucleic acids. The detection methods are based on change of solubility of hydrophobic probes upon hybridization with a polynucleotide. In one embodiment, the probes are morpholino probes, having a fluorophore attached thereto. The morpholino probes are immobilized on a substrate that has fluorescence quenching functionality.

Detection of unlabeled nucleic acids by changing solubility of surface-associating probes

Use of Morpholinos, a class of uncharged DNA analogues, for surface-hybridization applications. Monolayers of Morpholino probes on gold supports are fabricated with methods similar to those employed with DNA, and are used to hybridize efficiently and sequence-specifically with target strands. Hybridization-induced changes in the interfacial charge organization are analyzed with electrochemical methods and compared for Morpholino and DNA probe monolayers. Molecular mechanisms connecting surface hybridization state to the interfacial capacitance are identified and interpreted through comparison to numerical Poisson-Boltzmann calculations. Positive as well as negative capacitive responses (contrast inversion) to hybridization are possible, depending on surface populations of mobile ions as controlled by the applied potential. Quantitative comparison of surface capacitance with target coverage (targets/area) reveals a near-linear relationship, and demonstrates sensitivities (limits of quantification) in the pg mmrange.

Capacitive morpholino diagnostics for analysis of nucleic acids

A method to monitor the progress of hybridization between nucleic acid strands in solution and Morpholino strands immobilized on a solid support such as a working electrode in-situ, in real-time, and using label-free electrochemical measurements sensitive to hybridization-induced changes in the near-surface dielectric constant and charge organization.

An active CMOS biosensor chip for fluorescent-based detection is provided that enables time-gated, time-resolved fluorescence spectroscopy. In one embodiment, analytes are loaded with fluorophores that are bound to probe molecules immobilized on the surface of the chip. Photodiodes and other circuitry in the chip are used to measure the fluorescent intensity of the fluorophore at different times. These measurements are then averaged to generate a representation of the transient fluorescent decay response unique to the fluorophores. In addition to its low-cost, compact form, the biosensor chip provides capabilities beyond those of macroscopic instrumentation by enabling time-gated operation for background rejection, easing requirements on optical filters, and by characterizing fluorescence lifetime, allowing for a more detailed characterization of fluorophore labels and their environment. The biosensor chip can be used for a variety of applications including biological, medical, in-the-field applications, and fluorescent lifetime imaging applications.

Growing community of inventors

Irvington, NY, United States of America

Rastislav Levicky