MXPA00006732A - Method and articles for transfection of genetic material - Google Patents

Abstract

A gene transfection particle includes a polymer, a support particle conjugated with the dendritic polymer, and genetic material conjugated with the dendritic polymer. The gene transfection particles are highly efficient and are capable of delivering higher quantities of genetic materials to cells, with reduced cell damage. A gene transfection method involves bombarding cells with conjugates of polymers and genetic material, with or without a support particle.

Description

METHOD AND ARTICLES FOR TRANSFECTION OF GENETIC MATERIAL FIELD OF THE INVENTION This invention relates to compositions of matter and methods that are useful in deliveries of genetic materials to the interior of plant and animal cells, and more particularly to gene transfection particles and particle bombardment methods for gene transfection. .

BACKGROUND OF THE INVENTION Bombardment with particles, also known as the gene gun method, provides a potentially effective method for introducing genetic materials into plant and animal cells in the treatment and control of a variety of genetic, neoplastic and infectious diseases, and to create transgenic species. Particle bombardment methods for introducing genetic materials into plant and animal cells involve accelerating microscopic particles coated with a genetic material through the cell membrane to deliver the genetic material into the cell. The driving force used to accelerate the particles can be generated by high voltage electrical discharge, helium pressure discharge or other means. The microscopic projectile transfection particles generally comprise a gold particle having a diameter from about 1 to 15 micrometers, and genetic materials adhered thereto. Gold particles are preferred because they are chemically inert, have no cytotoxic effects on cells, and have a high density that allows superior momentum and penetration into cells. Agglutination agents such as spermidine (N-3-aminopropyl-1-4-butanediamine) have been used to bond genetic materials to gold particles. A disadvantage with known methods of particle bombardment is that they may not provide a sufficient amount of genetic material to achieve a desired therapeutic effect without causing unacceptable high levels of cell damage. Ning-Sun Yong et al., In Gene Therapeutics: Methods and Applications of Direct Gene Transfer, have reported that for one-cell cell cultures with sources with cells of 15-20 micrometers in size, a bombardment density with particles of 0.1 particles per square centimeter of 0.9 micrometer particles, which deliver approximately two particles per cell, results in more than 90% of cells in one layer and 75% of cells in suspension that are viable and healthy after bombardment with particles, but that for In most tissue samples, higher densities of particle bombardment cause excessive damage to cells and tissues. Due to the relatively low binding capacity of the linear polyamines used to bind genetic materials to gold particles, and the relatively low levels of particle bombardment that can be tolerated without excessive cell damage, the known transfer particles may not be capable of introducing sufficient amounts of genetic materials into cells to achieve a desired therapeutic effect or another while avoiding excessive cell damage. Accordingly, there is a need for transfection particles that are capable of delivering larger amounts of genetic materials to cells using particle bombardment methods while minimizing cell damage.

BRIEF DESCRIPTION OF THE INVENTION The invention provides highly efficient transfection particles and bombardment methods which are capable of delivering larger quantities of genetic materials to cells while minimizing damage to cells. The gene transfection particles of this invention comprise a composite material that includes a polymer, a support particle conjugated to the polymer, and genetic material conjugated by the polymer. The bombardment method of this invention involves the steps of forming a gene transfection particle that includes a polymer, and conjugated genetic material, with or without a support particle, and accelerating the gene transfection particle to a cell with motor force enough to cause the gene transfection particle to penetrate and enter the cell. An advantage of the invention is that it provides a method by which the density of the gene transfection particles can be adjusted as required depending on the robustness of the cell membrane that must be penetrated.

DESCRIPTION OF THE REFERED MODALITIES The gene transfection particles of the preferred embodiment of the invention preferably include genetic material which is conjugated to a polymer, and a metal, in the form of one or more atoms, one or more complex ions, groups, or particles, or other support that is also conjugated with the polymer. The metal component provides the transfection particles of the gene with the density necessary to reach the momentum that is necessary to penetrate the wall and / or cell membrane when the particles are accelerated towards the cell so that the transported genetic material can be delivered inside the cell. The metal used in preparing the gene transfection particles must be chemically inert in the environment of the cell, having essentially no, or at least very few, cytotoxic effects on the cells, and being able to be conjugated with a dendritic polymer. The metal preferably has a relatively high density to allow greater momentum and, hence, an adequate penetration of the wall and / or cell membrane. Gold is currently preferred due to its established acceptance for use in gene therapy. However, other metals can be used in certain applications. Examples of metals that may be suitable for use in gene therapy methods with particle bombardment include gold, tungsten, silver, copper, magnesium, calcium and combinations thereof. The metal component can be conjugated to the dendritic polymer in the form of an individual atom, ion, or complex, or in the form of groups of atoms or particles of microscopic size. In addition to metal particles, other suitable supports include silica particles, alumina particles, and other solid supports having surface functionality of Lewis acid. Also, it has been determined that dendritic polymers conjugated with genetic materials, without any metals or other support materials conjugated therewith can also be usefully used as gene transfection particles in particle bombardment methods. Gene transfection particles prepared by contacting a dendritic polymer with a metal atom or an entity containing a metal atom, and a genetic material can have a maximum diameter or dimension from about 1 nm to about 15 nm. The particles made up of groups or dendritic aggregates can have a maximum dimension from about 2 nm to at least several microns. However, the gene trnfection particles of this invention preferably have a particle size from about 1 nm to about 1000. nm, and more preferably from about 1 nm to about 100 nm. Genetic materials that can be used in the preparation of gene transfer particles of this invention include biological response modifiers, such as interleukins, interferons, and virus viral fragments and other genetic materials. The term "genetic material" as used herein refers to nucleotide-based materials, including without limitation, viruses and viral fragments, deoxyribonucleic acid. { DNA), plasmids, ribonucleic acid (RNA), messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), catalytic RNA (cRNA), minor nuclear RNA (snRNA), exons, introns, codons, and antisense oligonucleotides. The genetic material, especially viruses and viral fragments, may incidentally include some protein. The polymers are preferably dendritic, but linear and other non-dendritic polymers may be suitable. The dendritic polymers used to prepare the gene transfection particles of the preferred embodiment generally include any dendritic polymers that include functional groups, inside and / or outside, that are capable of binding or conjugating the metal to the dendritic polymer. The dendritic polymers used to coat the metal particles have surface functional groups that have an affinity for (i.e., the surface of the support particles will be stuck to, with preferred dendritic polymers those having amine functional groups, e.g., such as PAMAM, POPAM and PEI dendritic polymers. Next, the conjugate dendritic polymer carrier particle is contacted with genetic material to form a highly efficient gene transfection particle which is capable of delivering larger amounts of genetic materials to a cell, as compared to gene transfection particles. known. This result can still be achieved with particles that are substantially smaller than known gene transfection particles, resulting in improved therapeutic effect and reduced cell damage. The dendritic polymers that can be used generally include any of the known dendritic architectures including dendrimers, regular dendrons, hyper-branched controlled polymers, dendrimers, and random hyper-branched polymers. Dendrical polymers are polymers with densely branched structures that have a large number of reactive groups. A dendritic polymer includes several layers or generations of repeating units which contain all one or more branch points. Dendritic polymers, including dendrimers and hyperbranched polymers, are prepared by condensation reactions of monomer units having at least two reactive groups. The dendrimers that can be used include those constituted by a plurality of dendrons that emanate from a common nucleus which can be a single atom or a group of atoms. Each dendron generally consists of terminal surface groups, junctions of inner branches that have branching functionalities greater than or equal to two, and divalent connectors that covalently connect junctions of neighboring branches. Dendrons and dendrimers can be prepared by convergent or divergent synthesis. The divergent synthesis of dendrons and dendrimers involves a process of molecular growth which occurs through a consecutive series of stepwise, geometrically progressive additions of branches on branches in a radially outward molecular direction to produce an ordered array of layered branched cells . Each dendritic macromolecule includes a core cell, one or more layers of internal cells, and an outer layer of surface cells, wherein each of the cells includes a single branch junction. The cells may be the same or different in chemical structure and branching functionality. The cells of superficial branches may contain groups either chemically reactive or passive functional. The chemically reactive surface groups can be used for further extension of dendritic growth or for modification of dendritic molecular surfaces. Chemically passive groups can be used for physically modified dendritic surfaces, such as for adjusting the ratio of hydrophobic to hydrophilic terminals, and / or for improving the solubility of the dendritic polymer for a particular solvent. The convergent syntheses of dendrimers and dendrons involve a growth process that starts from what will become the surface of the dendron or dendrimer and progresses radially in a molecular direction to a point or focal nucleus. Dendritic polymers can be ideal or not ideal, that is, imperfect or defective. I / nperfections are usually a consequence of either incomplete chemical reactions, or unavoidable lateral reactions of competition. In practice, real dendritic polymers are generally non-ideal, that is, they contain certain amounts of structural imperfections.

The hyperbranched polymers that can be used represent a class of dendritic polymers that contain high levels of non-ideal irregular branching compared to the regular structure closest to the perfect dendronßs and dendrimers. Specifically, the hyper-branched polymers contain a relatively high number of irregular branching areas in which each repeating unit does not contain a branch junction. The preparation and characterization of dendrimers, dendrons, random hyper-branched polymers, hyper-branched controlled polymers, and dendrimers are well known. Examples of dendrimers and dendrons, and methods for synthesizing them are set forth in US Patents. Nos. 4,507,466; 4,558, 120; 4,568,737; 4,587,329; 4,631, 337; 4,694,064; 4,713,975; 4,737,550; 4,871, 779 and 4,857,599. Examples of hyperbranched polymers and methods for preparing the same are disclosed, for example in the U.S. Patent. No. 5,418,301. The dendritic polymers or macromolecules useful in the practice of this invention are characterized by a relatively high degree of branching, which is defined as the average fraction in number of branching groups per molecule, i.e., the ratio of groups plus groups of branches to the total number of terminal groups, branched groups and linear groups. For ideal dendrons and dendrimers, the degree of branching is 1. For linear polymers, the degree of branching is 0. Hyper-branched polymers have a degree of branching that is intermediate between that of linear polymers and ideal dendrimers, if preferred. a degree of branching of at least about 0.5 or greater. The degree of branching is expressed as follows: ? N, + Nt + Nt where Nx is the number of units type x in the structure. Both units, terminal (type t) and branched (type b) contribute to the completely branched structure while linear units (type 1) reduce eff ecting factor; from here that O = ?. = l where fbt = 0 represents the case of a linear polymer and br = 1 represents the case of a fully branched macromolecule. Dendritic polymers suitable for use with the invention also include macromolecules commonly referred to as cascade molecules, arboroles, arborescent grafted molecules, and the like. Suitable dendritic polymers also include bridged dendritic polymers, i.e., dendritic macromolecules linked together either through surface functional groups or through a binding molecule that connects surface functional groups together, and dendritic polymer aggregates held together by physical forces. Also included are spherical shaped dendritic polymers and rod or rod shaped dendritic polymers grown from a polymeric core. The dendritic polymers used in the practice of this invention can be generationally monodisperse or generationally polydisperse. The dendritic polymers in a monodisperse solution are substantially all of the same generation, and therefore of uniform size and shape. The dendritic polymers in the polydisperse solution comprise a distribution of polymers of different generation. The dendritic polymer molecules that can be used in the practice of this invention include mixtures of different compositions or functionalities inside or outside. Dendritic polymers that are useful in the practice of this invention include those having symmetric branch cells (arms of equal length, eg, PAMAN dendrimers) and those having asymmetric branch cells (arms of unequal length, eg, branched dendrimers with lysine. ) branched dendrimers, cascade molecules, arbories, and the like. The term "dendritic polymer" also includes so-called "hyper-branched peak" polymers. These comprise non-interlaced poly-branched polymers prepared by (1) forming a first bundle of linear polymer branches by initiating the polymerization of a first package of monomers that are either protected against or unreactive for branching and grafting, during polymerization, each of the branches having a reactive final unit at the end of the polymerization, the reactive final units being unable to react between them; (2) grafting the branches to a core molecule or core polymer having a plurality of reactive sites capable of reacting, with the reactive end groups on the branches; (3) or unprotecting or activating a plurality of monomer units in each of the branches to create reactive sites; (4) separately forming a second bundle of linear polymer branches repeating step (1) with a second package of monomers; (5) joining the second bundle of branches to the first bundle of branches by reacting the reactive end groups of the second bundle of branches with the reactive sites in the first bundle of branches, and then repeating steps (3), (4) and ( 5) above to add one or more subsequent bundles of branches. Such peak hyper-branched polymers are described in European Patent Publication 0473088A2. A representative formula for such a hyper-branched peak polymer is; C i I < ? -W > . * Ri wherein C is a core molecule; each R is the residual portion of an initiator selected from a group consisting of free radical initiators, cationic initiators, anionic initiators, coordination polymerization initiators, and group transfer initiators; A and B are polymerizable monomers or comonomers capable of withstanding the conditions required for branching therefrom or grafting thereto, at least during the polymerization of the linear polymer chain. { (A) - (B)} and during your Grafting to a branch. { (A) - (B)} previous of the core branch. { (A) - (B)}; each G is a G graft component, and the designation. { . { A) (t.y) - (B) y} indicates that G can join either a unit (A) or a unit (B); n is the degree of polymerization of the peak branches of the indicated generation; y is the fraction of units B in the branch of the indicated generation, and has a value of 0.01 to 1; superscripts 0, 1 and i designate the generation level of the peak branch, with i starting at "2" and continuing for the number of generations of repetitive branch bundles in the polymer; and at least r \ ° and n 'are = 2. For purposes of clarifying the terminology it should be noted that the dense star dendrimers are constructed by reiterative terminal branching, while the hyper-ramified dendrimers on the crest are constructed by repetitive crest branching. In dense star dendrimers, the branches of subsequent generations are attached to the terminal portions of a previous generation, thus limiting the degree of branching with the functionality of the terminal portion of the previous generation, to which it would typically be two or three. In contrast, by branching olímeros on oligomer branches of previous generation according to the hyper-ramified dendrimer in crest, one can dramatically increase the degree of branching from generation to generation, and the degree of branching of generation to generation.

Dendritic polymers that are particularly well suited for use in the preparation of gene transfection particles of this invention include various dendritic polymers containing primary or secondary primary and secondary amine groups, amide groups or combinations thereof. Examples include detritic potamidoamine polymers (PAMAM), polypropylamide dendritic polymers (POPAM), and polyethylenimine dendritic polymers (PEI). Dendritic polymers having amide and / or amine groups have a very high affinity and agglutination ability both for metals and for genetic materials. According to a preferred aspect of the invention, a support particle, preferably metal, is first conjugated with a dendritic polymer to form a metal / dendrimer compound that is subsequently contacted with a genetic material to form gene transfection particles. . "Conjugation," as used herein, refers to any of several interactions between the dendritic polymer and the support, in which the support is bound to the dendritic polymer or otherwise located with respect to the dendritic polymer so that it can be used the density of the support to impart sufficient momentum to the gene transfection particle during the bombardment with particles to achieve cell penetration and introduction of the genetic material into the cell. Thus, conjugation, as used herein, encompasses chemical bonding, such as complex formation, hydrogen bonding, dipole-dipole interactions, London scattering forces, Van der Waals interactions, as well as controlled retention by physical entrapment or diffusion of the support within the interior of a dendritic polymer. The metal that is conjugated to the dendritic polymer can be in the form of individual metal atoms or portions containing metal atoms which are attached to functionally reactive sites inside or outside of a dendritic polymer molecule, or entrapped or physically retained within the interior of the dendritic polymer molecule. The metal that is conjugated to the dendritic polymer may also be in the form of a group of metal atoms or a metat particle to which the dendritic polymer (s) is attached. Conjugates or compounds of metal dendritic polymer in which the metal is in the form of a metal atom or portion containing metal atoms attached to, trapped with, or retained within a dendritic polymer molecule can be prepared by placing a an entity that contains metal atoms (such as a metal atom, a metal ion, or metal-containing complex or molecule) with respect to a dendritic polymer. Location (positioning), as used herein, involves contacting the dendritic polymer with an entity containing metal atoms under suitable conditions for a suitable period to allow the metal-containing entity to chemically conjugate with inner or outer reactive sites, or both, and / or arranged within the interior of the dendritic polymer molecule. Physical restraint may range from relatively momentary containment of reagent or reagents inside or outside of the dendritic polymer. The binding of the reagent or reagents to the interior or exterior of the dendritic polymer includes ionic binding, acceptor donor interactions (coordination junction), hydrogen bonding, Van der Waals interactions, and London dispersion interactions. Entities containing metal atoms can be physically entrapped within the interior of a dendritic polymer by contacting an entity containing metal atoms with a dendritic polymer having an interior that is accessible to the entity containing metal atoms, under conditions and for a period sufficient to allow the entities containing sß metal atoms to be disposed within the interior of the dendritic polymer molecule, and subsequently react with the entity containing metal atoms to form a compound or ion which is physically trapped within the interior of the dendritic polymer molecule, and / or modifying the surface of the dendritic polymer molecule so that the dendrimer is no longer permeable to the entity containing metal atoms. For example, metal ions may generally enter the interior defined by generation 4 through PAMAM dendrimers, and subsequently react with a complexing agent that is also capable of penetrating the surface of the dendrimer to form a composite that is incapable of Leave the inside of the dendrimer given its physical size and / or shape. Methods for trapping entities containing metal atoms within the interior of a dendritic polymer by modifying the surface groups sß describe, for example, European Patent Application 95201373.8 (Publication No. 0,684,044 A2). Conjugates of metal dendritic polymer in which the metal is distributed in and / or within the dendritic polymer in the form of individual atoms or portions containing a single metal atom can be contacted with genetic material to form transfection particles. of gene. All genetic materials contain an acid functionality which will bind rapidly and tenaciously with several functionally surface reactive sites in dendritic polymers, especially with amine and amide functional groups. Due to the high ata surface density of functional groups in relatively high amounts of dendritic polymers (eg, a fifth generation of PAMAM dendrimer has 128 amine-binding sites) of genetic material can be conjugated to a dendritic polymer to form transfection particles of gene that have a much higher level of genetic material for mass and particle size than the known gene transfection particles. As a result, effective amounts of genetic material can be delivered to the interior of a cell using fewer particles, and using smaller particles. Each of these factors can contribute to lower levels of celtilar damage during bombardment with particles and, therefore, higher levels of cell and tissue viability after bombardment with particles. The dendritic polymer conjugates with metal described above can be combined or conjugated, including or with dendritic polymers that do not include any metal, to form groups or aggregates of dendritic polymers having a larger diameter or maximum dimension than a single polymer molecule dendritic The conjugation of polymers of dithytics into groups or aggregates can be achieved by linking by coordination of at least two different dendritic polymer molecules to a single metal atom, or by the use of divalent, trivalent or other polyvalent crosslinking agents, which may be linear or branched polymers or other macromolecules, including dendritic polymers having surface functional groups that will directly bind to the surface functional groups of other dendritic polymers. When two or more different types of dendritic polymers are used have different types of surface functional groups to form groups of dendritic polymers with metal by direct reaction of the different types of surface functional groups between them, different types of dendrimers can be reacted first among them to form groups or aggregates, and subsequently contacted with an entity containing metaphic atoms, or one or more different types of dendritic polymers can be contacted with an entity containing metal atoms to form one, or more, conjugate (s) of metal dendritic polymers which are, or are, subsequently reacted with the other dendritic polymer and / or metal dendritic polymer conjugate to form groups or aggregates of metal-containing dendritic polymers. The genetic material can be contacted with the dendritic polymer, or polymers, before, during, or after the dendritic polymer, or polymers have been contacted with the entity or entities containing metal atoms, or a combination thereof. . The loading of metat and genetic material can be controlled as desired, such as by carefully controlling the quantities of materials that come into contact with each other, by selecting polymer or dendritic polymers with respect to type, size, generation and surface functionality, controlling the conditions under which the components are contacted, etc. By appropriate selection of polymer or dendritic polymers, crosslinkers, if any, the type and quantity of the entity or entities that contain metallic atoms, the level of metal charge and genetic material, the manner in which and the conditions under which When the components are combined, any of several particle sizes, particle densities and therapeutic activities can be achieved that meet specific requirements related to the type of cell being treated and the type of disease being treated. According to another aspect of the invention, gene transfection particles can be prepared by coating dendritic polymer molecules on the surface of a metal particle. Suitable gold particles, provided in the form of gold soles, are commercially available from a variety of different suppliers. Preferred metal particles according to this invention have a maximum diameter or dimension below 1 micrometer, and more preferably from about 1 nm to about 100 nm. In addition to the tremendous advance in relation to the improved effectiveness and reduced cell damage associated with this invention, it has been found that the particles of this invention provide better protection of the genetic material against degradation by nuclease, and can therefore extend the period of therapeutic effectiveness. The method of this invention involves accelerating any of the gene transfection particles described therein to a plant or animal cell with sufficient force to cause the gene transfection particle to penetrate and enter the cell. The method can be performed in vivo or in cells that are normally exposed, such as epidemial cells, in vivo in cells that are exposed by surgical methods, such as transplanted to a host plant or animal after particle bombardment, or in vitro, such as gene amplification techniques or in the mass production of certain gene products. Bombardment of particles using the gene transfection particles of this invention can be achieved using any of the various gene guns that are now well known in the art and literature, including high-voltage electrical discharge devices, apparatus pressure discharge, and other suitable means that have been or will be developed. The gas used in the pressure discharge apparatus must be essentially inert to the support, genetic material and polymer. Suitable inert gases include, for example, helium and argon.

Additional understanding will be provided by reference to the following illustrative, non-limiting examples.

EXAMPLE 1 A dendrimer-gold conjugate was prepared by mixing 500 μl of a 1.0 M solution of a G4.T PAMAM dendrimer with 500 μl of a 10.15 M solution of HAuCl. 10 μl of a hydrazine solution in 35% water, and 2 ml (2000 μl) of water, at room temperature. (ßG4.T * denotes a fourth generation PAMAM dendrimer in which the amine terminals are modified by reaction with tris-hydroxy methyl aliphatic surface groups). The formation of dendrimer-gold conjugates was confirmed by ultraviolet spectroscopy.

EJ5MPM3 2 The dendrimer-gold conjugate of Example 1 can be contacted with any of several genetic materials to form a highly efficient gene transfection particle. It will be apparent to those skilled in the art that various modifications may be made to the preferred embodiment of the invention as described herein without departing from the spirit or scope of the invention as defined in the appended claims.

Claims (28)

1. CLAIMS 1. A gene transfection particle comprising a composite material including a polymer, a support conjugated to the dendritic polymer, and genetic material conjugated to the dendritic polymer.
2. 2. The particle of claim 1, wherein the support particle is a metal selected from gold, tungsten, silver, copper, magnesium, calcium or a combination thereof.
3. 3. The particle of claim 1, wherein the support particle is gold.
4. 4. The particle of claim 1, wherein the polymer is a dendritic polymer having amine functional groups.
5. 5. The particle of claim 4, wherein the dsndritic polymer is a PAMAM, POPAM or PEI.
6. 6. The particle of claim 4, wherein the dendritic polymer is a PAMAM.
7. 7. The particle of claim 1, having a maximum dimension from about 1 nm to about 1000 nm.
8. 8. The particle of claim 1, wherein the genetic material is DNA, a fragment of DNA, or an oligonucleotide.
9. 9. The particle of claim 3, wherein the polymer is a dendritic polymer having amine functional groups.
10. 10. The particle of claim 3, wherein the dendritic polymer is a PAMAM. 1.
11. The particle of claim 10, having a maximum dimension from about 1 nm to about 1000 nm.
12. The particle of claim 1, wherein the polymer is dendritic, and the metal conjugated to the dendritic polymer is in the form of a single metal atom or atoms or ions, or compounds containing a single metal atom.
13. 13. The particle of claim 12, wherein the metal is gold, tungsten, silver, copper, magnesium, calcium or a combination thereof.
14. 14. The particle of claim 12, when the metal is gold.
15. 15. The particle of claim 12, wherein the dendritic polymer is a polyamine.
16. 16. The particle of claim 12, wherein the dendritic polymer is a PAMAM, POPAM or PEI.
17. 17. The particle of claim 12, wherein the dendritic polymer is a PAMAM.
18. 18. The particle of claim 12, having a maximum dimension from about 1 nm to about 1000 nm.
19. 19. The particle of claim 14, wherein the dendritic polymer is a polyamine.
20. 20. The particle of claim 14, wherein the dendritic polymer is a PAMAM.
21. 21. The particle of claim 20, having a maximum dimension from about 1 nm to about 100 nm.
22. 22. A gene transfection particle comprising a metal core particle, dendritic polymer molecules attached to the surface of the metal core particle, and genetic material attached to the dendritic polymer.
23. 23. A method for delivering genetic material to plant or animal cells comprising: conjugating a polymer to a support to form a polymer-carrier conjugate; conjugate genetic material with the polymer-support conjugate to form a gene transfection particle; and accelerating the gene transfection particle to a plant or animal cell with sufficient motive force to cause the gene transfection particle to penetrate and enter the cell.
24. The method of claim 23, wherein the polymer is dendritic, and which further includes conjugating the dendritic polymer with a support particle.
25. 25. The method of claim 23, wherein the gene transfection particle is accelerated with a high voltage electrical discharge.
26. 26. The method of claim 23, wherein the gene transfection particle is accelerated with pressure discharge.
27. 27. The method of claim 23, wherein the gene transfection particle is accelerated to a cell in vivo. The method of claim 23, wherein the gene transfection particle is accelerated to an explant cell, and further comprising the step of transplanting the cell containing the gene transfection particle into a host plant or animal.