Nanoscale apertures that provide a fluidic path between two reservoirs can be used for numerous applications. These applications include patch-clamp type measurements, Coulter counting and molecular studies. For Coulter counting of nanometer-sized analytes, we have developed a process capable of reproducibly fabricating cylindrical apertures in a silicon-on-insulator substrate with diameters less than 30 nm. The fabrication process utilizes electron beam lithography for the lithographic definition of the apertures enabling accurate control of final device dimensions. Measurements of the conductance of the pores as a function of KCl concentration reveal the presence of a surface conduction mechanism that dominates the conductance of the nanopore and leads to a deviation of the concentration dependence of the conductance from the case of bulk solution. From current traces recorded, the passage of individual particles through the pore can be concluded.

Carbon nanotubes have many unique properties such as high surface area, hollow cavities, and excellent mechanical and electrical properties. Interfacing carbon nanotubes with biological systems could lead to significant applications in various disease diagnoses. Significant progress in interfacing carbon nanotubes with biological materials has been made in key areas such as aqueous solubility, chemical and biological functionalization for biocompatibility and specificity, and electronic sensing of proteins. Bioconjugated nanotubes combined with the sensitive nanotube-based electronic devices would enable sensitive biosensors toward medical diagnostic. Furthermore, recent findings of improved cell membrane permeability for carbon nanotubes would also expand medical applications to therapeutics using carbon nanotubes as carriers in gene delivery systems. One of the main issues in nanobio systems is the specificity, which requires biofunctionalization of nanomaterials for recognition of only one type of target biomolecule. This study presents an effective functionalization scheme for preventing non-specific antibody binding on nanotubes. Non-specific antibody binding on nanotubes was successfully prevented by co-adsorption of a bio-compatible polymer PEG and a surfactant (NaDDBS) on nanotubes. Optical studies through confocal microscopy revealed very minimal non-specific antibody binding on the PEG/NaDDBS-coated nanotubes (WCC < 0.05) compared to high degree of non-specific antibody binding on nanotubes without PEG pretreatment (WCC > 0.80), as determined by weighted co-localization coefficients (WCC). In addition to the confocal microscopy studies, electronic detection studies revealed that PEG/NaDDBS pretreated devices exhibited very little conductance change due to antibody adsorption compared to the devices without any PEG/NaDDBS pretreatment. These findings indicate that the PEG/NaDDBS pretreatment is a very effective functionalization scheme in preventing non-specific antibody binding on nanotubes.

A cell-driven self-assembly of intracellular nano-device was proposed for bio-hybrid interface. This cells-driven self-assembly employed cell migration force to insert a conductive nanoneedle which would be worked as intracellular electrode. Such a nanoneedle was fabricated in the bottom of a microwell using focused ion beam induce deposition. The microwell structure with a coating of cell adhesion molecules was employed as the scaffold of the cell migration. A glass plate with the microwells had a non cell binding coating of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer as an anti-biofouling material. Thus a cell adhered only on the wall of a microwell then the cell migrated into the microwell. Adhesion force and migration force induced self-insertion of the nanoneedle into a live cell body using the cell's own migration force. The inserted nanoneedle was made of electrical conductive tungsten, so the intracellular nanoneedle might extract intracellular potential more precisely than extracellular electrode, while inducing much less damage to cells. In the future, the technique of cell-driven self-insertion of nanoneedle may be integrated with multi electrode arrays for developing long-lasting measurements device on cellular network researches, or the risk assessment of the nanomaterials on cellular activities.

The on-chip application of single, sub-ms voltage pulses promotes the immobilization of single stranded DNA (ssDNA) probes from a solution to a chemically functionalized SiO2 surface and as well as the hybridization between ssDNA targets from a solution to covalently immobilized ssDNA probes (E-assisted DNA reactions). Compared to diffusion-based surface reactions (in the absence of the applied electric field), an improvement of several orders of magnitude in the kinetics of the immobilization and hybridization reactions is observed with low amplitude (below 2 V) and short duration (100 ns to 1 ms) voltage pulses. E-assisted DNA reactions are demonstrated using mm-size macroelectrodes and then optimized using μm-size microelectrodes.