Gary Blackburn

Bioelectronic DNA detection of human papillomaviruses using eSensor™: a model system for detection of multiple pathogens

BackgroundWe used human papillomaviruses (HPV) as a model system to evaluate the utility of a nucleic acid, hybridization-based bioelectronic DNA detection platform (eSensor™) in identifying multiple pathogens.MethodsTwo chips were spotted with capture probes consisting of DNA oligonucleotide sequences specific for HPV types. Electrically conductive signal probes were synthesized to be complementary to a distinct region of the amplified HPV target DNA. A portion of the HPV L1 region that was amplified by using consensus primers served as target DNA. The amplified target was mixed with a cocktail of signal probes and added to a cartridge containing a DNA chip to allow for hybridization with complementary capture probes.ResultsTwo bioelectric chips were designed and successfully detected 86% of the HPV types contained in clinical samples.ConclusionsThis model system demonstrates the potential of the eSensor platform for rapid and integrated detection of multiple pathogens.

Ferrocene and Maleimide-Functionalized Disulfide Scaffolds for Self-Assembled Monolayers on Gold

A series of ferrocene-based electroactive molecules (EAMs) containing maleimide and disulfide groups in different asymmetric and branched architectures were designed and synthesized. Stable monolayers of each EAM on gold electrodes were confirmed by cyclic voltammetry. Importantly, these EAMs expand the repertoire of monolayer building blocks amenable to modular biofunctionalization for applications in electrochemical biosensor fabrication.

Electroactive self-assembled monolayers on gold via bipodal dithiazepane anchoring groups.

Novel dithiazepane-functionalized ferrocenyl-phenylethynyl oligomers 1 and 2 have been synthesized. Self-assembled monolayers (SAMs) of these ferrocene derivatives have been studied by X-ray photoelectron spectroscopy, ellipsometry, and cyclic voltammetry. It has been shown by XPS that monolayers of the dithiazepane-anchored molecules on gold electrodes contain gold-thiolate species. Cyclic voltammetry of the SAMs were characteristic of stable electroactive monolayers even for single-component SAMs of 1 and 2, with the more ideal responses recorded for the two-component SAMs diluted with undecanethiol. The small variation in peak splittings at progressively higher scan rates in these SAMs makes dithiazepane-bridged redox species promising candidates for further studies on molecular wires with bipodal anchoring.

Electronic detection of DNA: robust platform for integrated devices

Sample-to-answer devices that both amplify and detect nucleic acid targets will find use in health-care, agricultural, forensic medicine, military applications, environmental monitoring and animal husbandry. Ideally, these devices will be able to start with almost any sample input, be inexpensive to manufacture, utilize portable instrumentation, and require no user intervention. In practice, developing devices that meet these criteria are difficult due to limitations imposed by the enzymatic amplification procedures, and the DNA detection platform. Motorolas Clinical Micro Sensors division has recently developed and commercialized an electronic nucleic acid detection platform that simplifies the process for building sample-to-answer devices.