Recent advancements in molecular biology have provided a number of techniques for manipulating the genetic material of a cell or organism. A particular subset of genetic engineering technology has facilitated the introduction of foreign genes in cells to alter their biological characteristics and morphology. The introduction of foreign genes in host cells within plants, for example, has been shown to improve vital traits such as insect resistance, frost resistance, and nutrient compositions. Another subset of genetic engineering technology seeks to read out the physiological state of a cell (e.g., biomarkers, physiological probes, reporters, indicator dyes, etc.), rather than to alter biological characteristics. Particularly useful in neuroscience and translational research, this molecular tool subset enables the visualization of various cellular changes including pH, cAMP, calcium, and membrane voltage. In recent years, the introduction of foreign genetic material in the form of gene therapy has been applied in treating diseased human tissue both in vivo and in vitro.
The introduction of foreign genetic material into a cell is commonly referred to as gene “transformation” in bacterial cells and gene “transfection” in animal cells. Both gene transformation and gene transfection can be conducted using several different approaches. One approach utilizes bacterial plasmids or viral vectors as carriers for delivering genes into cells. Other approaches, such as electroporation and microinjection, involve the physical disruption of a cell membrane to allow the introduction of foreign genetic material. Electroporation involves the use of electrical impulses to increase cell membrane and cell wall permeability to DNA contained in a solution surrounding the cell. Microinjection is a technique involving the injection of DNA directly into a cell nucleus using an ultrafine needle. Lipofection, also known as liposome transfection, is a technique used to introduce foreign genetic material into a cell by means of liposomes, which are vesicles that possess phospholipid bilayers, for example, that can fuse with a cell membrane.
Transfection by particle bombardment is a physical method of gene transfection in which high density, sub-cellular sized particles coated with foreign genetic material are accelerated to high velocity to carry the genetic material into cells. Because particle bombardment transfection does not depend on specific receptors or biochemical features typically present on cell surfaces, it can be readily applied to a variety of biological systems including plants and mammalian tissue. Also, since particle bombardment transfection involves the delivery of particles to cells at high velocity, it can overcome physical barriers to effective gene transfer, such as the stratum corneum of the epidermis, inner limiting membrane of the retina, and the cell wall of plants. In order to generate high velocity particles, known delivery systems typically subject the particles to the flow of a highly pressurized gas. However, the highly pressurized gas can cause substantial tissue damage if its pressure is not reduced before it contacts the tissue.
Accordingly, it would be useful to have delivery devices and methods that are capable of delivering molecules into tissues with minimal or no tissue damage. Particle based delivery devices and methods may be particularly useful. It would also be beneficial to have particle based delivery devices that can be operated to tailor operating parameters to particular tissues and research situations. Kits including these devices would also be useful.