Tim McKnight

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Timothy Eric McKnight is an American biologist. He has been a key developer of a cell transfecting method using vertically aligned carbon nanofibers. Arrays of vertically aligned carbon nanofibers are modified with DNA and pressed into cells and tissue. Surviving cells can express DNA that is delivered during the penetration event, even when the DNA is covalently bound to the penetrant nanofiber element. This gene delivery technique has been termed Impalefection.

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Transfection is the process of deliberately introducing naked or purified nucleic acids into eukaryotic cells. It may also refer to other methods and cell types, although other terms are often preferred: "transformation" is typically used to describe non-viral DNA transfer in bacteria and non-animal eukaryotic cells, including plant cells. In animal cells, transfection is the preferred term as transformation is also used to refer to progression to a cancerous state (carcinogenesis) in these cells. Transduction is often used to describe virus-mediated gene transfer into eukaryotic cells.

Transfer DNA

The transfer DNA is the transferred DNA of the tumor-inducing (Ti) plasmid of some species of bacteria such as Agrobacterium tumefaciens and Agrobacterium rhizogenes(actually an Ri plasmid). The T-DNA is transferred from bacterium into the host plant's nuclear DNA genome. The capability of this specialized tumor-inducing (Ti) plasmid is attributed to two essential regions required for DNA transfer to the host cell. As the T-DNA is bordered by 25-base-pair repeats on each end. Transfer is initiated at the right border and terminated at the left border and requires the vir genes of the Ti plasmid.

Nanorobotics nanotechnology engineering

Nanorobotics is an emerging technology field creating machines or robots whose components are at or near the scale of a nanometer. More specifically, nanorobotics refers to the nanotechnology engineering discipline of designing and building nanorobots, with devices ranging in size from 0.1–10 micrometres and constructed of nanoscale or molecular components. The terms nanobot, nanoid, nanite, nanomachine, or nanomite have also been used to describe such devices currently under research and development.

Molecular machine Molecular-scale artificial or biological device

A molecular machine, nanite, or nanomachine, is a molecular component that produces quasi-mechanical movements (output) in response to specific stimuli (input). In biology, macromolecular machines frequently perform tasks essential for life such as DNA replication and ATP synthesis. The expression is often more generally applied to molecules that simply mimic functions that occur at the macroscopic level. The term is also common in nanotechnology where a number of highly complex molecular machines have been proposed that are aimed at the goal of constructing a molecular assembler.

M13 bacteriophage species of virus

M13 is a filamentous bacteriophage composed of circular single-stranded DNA (ssDNA) which is 6407 nucleotides long encapsulated in approximately 2700 copies of the major coat protein P8, and capped with 5 copies of two different minor coat proteins on the ends. The minor coat protein P3 attaches to the receptor at the tip of the F pilus of the host Escherichia coli. The life cycle of M13 is relatively short, with the early phage progeny exiting the cell ten minutes after infection. M13 is a chronic phage, releasing its progeny without killing the host cells. The infection causes turbid plaques in E. coli lawns, of intermediary opacity in comparison to regular lysis plaques. However, a decrease in the rate of cell growth is seen in the infected cells. M13 plasmids are used for many recombinant DNA processes, and the virus has also used for phage display, directed evolution, nanostructures and nanotechnology applications.

Lipogenesis is the metabolic process through which acetyl-CoA is converted to triglyceride for storage in fat. The triglycerides in fat are packaged within cytoplasmic lipid droplets. The process begins with acetyl-CoA, which is an organic compound used to transfer energy from metabolism of carbohydrates, fatty acids, and ethanol. Through the citric acid cycle, acetyl-CoA is broken down to produce ATP, which is then an energy source for many metabolic processes, including protein synthesis and muscle contraction.

Carbon nanofiber

Carbon nanofibers (CNFs), vapor grown carbon fibers (VGCFs), or vapor grown carbon nanofibers (VGCNFs) are cylindrical nanostructures with graphene layers arranged as stacked cones, cups or plates. Carbon nanofibers with graphene layers wrapped into perfect cylinders are called carbon nanotubes.

Buckypaper thin sheet made from an aggregate of carbon nanotubes

Buckypaper is a thin sheet made from an aggregate of carbon nanotubes or carbon nanotube grid paper. The nanotubes are approximately 50,000 times thinner than a human hair. Originally, it was fabricated as a way to handle carbon nanotubes, but it is also being studied and developed into applications by several research groups, showing promise as vehicle armor, personal armor, and next-generation electronics and displays.

V(D)J recombination is the unique mechanism of genetic recombination that occurs only in developing lymphocytes during the early stages of T and B cell maturation. It involves somatic recombination, and results in the highly diverse repertoire of antibodies/immunoglobulins and T cell receptors (TCRs) found in B cells and T cells, respectively. The process is a defining feature of the adaptive immune system.

Nanofiber natural or synthetic fibers with diameters in the nanometer range

Nanofibers are fibers with diameters in the nanometer range. Nanofibers can be generated from different polymers and hence have different physical properties and application potentials. Examples of natural polymers include collagen, cellulose, silk fibroin, keratin, gelatin and polysaccharides such as chitosan and alginate. Examples of synthetic polymers include poly(lactic acid) (PLA), polycaprolactone (PCL), polyurethane (PU), poly(lactic-co-glycolic acid) (PLGA), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(ethylene-co-vinylacetate) (PEVA). Polymer chains are connected via covalent bonds. The diameters of nanofibers depend on the type of polymer used and the method of production. All polymer nanofibers are unique for their large surface area-to-volume ratio, high porosity, appreciable mechanical strength, and flexibility in functionalization compared to their microfiber counterparts.

In molecular biology, SNP array is a type of DNA microarray which is used to detect polymorphisms within a population. A single nucleotide polymorphism (SNP), a variation at a single site in DNA, is the most frequent type of variation in the genome. Around 335 million SNPs have been identified in the human genome, 15 million of which are present at frequencies of 1% or higher across different populations worldwide.

Impalefection is a method of gene delivery using nanomaterials, such as carbon nanofibers, carbon nanotubes, nanowires. Needle-like nanostructures are synthesized perpendicular to the surface of a substrate. Plasmid DNA containing the gene and intended for intracellular delivery, is attached to the nanostructure surface. A chip with arrays of these needles is then pressed against cells or tissue. Cells that are impaled by nanostructures can express the delivered gene(s).

Direct-current plasma

Direct-current plasma (DCP) is a type of plasma source used for atomic emission spectroscopy that utilizes three electrodes to produce a plasma stream. The most common three-electrode DCP apparatus consists of two graphite anode blocks and a tungsten cathode block arranged in an inverted-Y arrangement. An argon gas source is situated between the anode blocks and argon gas flows through the anode blocks. The plasma stream is produced by briefly contacting the cathode with the anodes. Temperatures at the arc core exceed 8000 K. This three-electrode arrangement is illustrated in Figure 1.

Nanoinjection is the process of using a microscopic lance and electrical forces to deliver DNA to a cell. It is claimed to be more effective than microinjection because the lance used is ten times smaller than a micropipette and the method uses no fluid. The nanoinjector mechanism is operated while submerged in a pH buffered solution. Then, a positive electrical charge is applied to the lance, which accumulates negatively charged DNA on its surface. The nanoinjector mechanism then penetrates the zygotic membranes, and a negative charge is applied to the lance, releasing the accumulated DNA within the cell. The lance is required to maintain a constant elevation on both entry and exit of the cell.

<i>Bienertia</i> genus of plants

Bienertia is a flowering plant genus that currently is classified in the family Amaranthaceae, although it was previously considered to belong to the family Chenopodiaceae.

In nanotechnology, carbon nanotube interconnects refer to the proposed use of carbon nanotubes in the interconnects between the elements of an integrated circuit. Carbon nanotubes (CNTs) can be thought of as single atomic layer graphite sheets rolled up to form seamless cylinders. Depending on the direction on which they are rolled, CNTs can be semiconducting or metallic. Metallic carbon nanotubes have been identified as a possible interconnect material for the future technology generations and to replace copper interconnects. Electron transport can go over long nanotube lengths, 1 μm, enabling CNTs to carry very high currents (i.e. up to a current density of 109 A∙cm−2) with essentially no heating due to nearly one dimensional electronic structure. Despite the current saturation in CNTs at high fields, the mitigation of such effects is possible due to encapsulated nanowires.

Synthesis of carbon nanotubes

Techniques have been developed to produce carbon nanotubes in sizable quantities, including arc discharge, laser ablation, high-pressure carbon monoxide disproportionation, and chemical vapor deposition (CVD). Most of these processes take place in a vacuum or with process gases. CVD growth of CNTs can occur in vacuum or at atmospheric pressure. Large quantities of nanotubes can be synthesized by these methods; advances in catalysis and continuous growth are making CNTs more commercially viable.

Vertically aligned carbon nanotube arrays (VANTAs) are a unique microstructure consisting of carbon nanotubes oriented along their longitudinal axis normal to a substrate surface. These VANTAs effectively preserve and often accentuate the unique anisotropic properties of individual carbon nanotubes and possess a morphology that may be precisely controlled. VANTAs are consequently widely useful in a range of current and potential device applications.

Tissue nanotransfection (TNT) is an electroporation-based technique capable of gene and drug cargo delivery or transfection at the nanoscale. Furthermore, TNT is a scaffold-less Tissue engineering (TE) technique that can be considered cell-only or tissue inducing depending on cellular or tissue level applications. The transfection method makes use of nanochannels to deliver cargo to tissues topically. 

Zinc oxide (ZnO) nanostructures are structures with at least one dimension on the nanometre scale, composed predominantly of zinc oxide. They may be combined with other composite substances to change the chemistry, structure or function of the nanostructures in order to be used in various technologies. Many different nanostructures can be synthesised from ZnO using relatively inexpensive and simple procedures.. ZnO is a semiconductor material with a wide band gap energy of 3.3eV and has the potential to be widely used on the nanoscale. ZnO nanostructures have found uses in environmental, technological and biomedical purposes including dye-sensitised solar cells, lithium-ion batteries, biosensors, nanolasers and supercapacitors. Research is ongoing to synthesise more productive and successful nanostructures from ZnO and other composites. ZnO nanostructures is a rapidly growing research field, with over 5000 papers published during 2014-2019.