Methods for Labeling Nonphagocytic Cells with MR Contrast Agents
Michel M. J. Modo, Jeff W. M. Bulte in Molecular and Cellular MR Imaging, 2007
Mechanical approaches that have been used primarily to introduce DNA or plasmids into the nucleus have been modified to directly introduce MRI contrast agents into cells. The gene gun fires DNA, plasmids, or DNA-coated nanoparticles directly into cells in culture, driving the particles through the cell membrane or directly into the nucleus,96,97 using a ballistic gas charge. SPIO nanoparticles and magnetic beads have been introduced into stem cells using a gene gun with high labeling efficiency,98 and the cells were implanted into rats, but no information was provided about the effects of the method on long-term cell viability, proliferation, differentiation capabilities, or reactive oxygen species. It should be noted that the gene gun approach is indiscriminant and will introduce MRI SPIO nanoparticles directly into the cell nucleus. Although it is beneficial to deliver DNA directly into the nucleus, the presence of SPIO nanoparticles in the nucleus could initiate a Fenton reaction and, through Haber-Weiss chemistry,99 result in the development of free radicals that could cause damage to DNA.
Microneedles vs. Other Transdermal Technologies
Boris Stoeber, Raja K Sivamani, Howard I. Maibach in Microneedling in Clinical Practice, 2020
The original biolistic particle delivery system, or gene gun, was designed for delivering exogenous DNA (transgenes) into plant cells. The payload is typically a particle of a heavy metal coated with DNA (typically plasmid DNA). This has been developed into biolistic injectors delivering a “shotgun” burst of nano- or microparticles into the skin (Figure 5.5 right), injectors that have been effective for the immunization of antigens including influenza and malaria, and also in anticancer applications in a range of animals (mice, rat, ferrets, monkeys, etc.) and humans (79–82). Clinical assessment of biolistic particle delivery reports transient localized pain and tissue damage (erythema, irritation, etc.); thus, like liquid biolistic injection, the technique is most suitable to vaccination.
Gene Therapy for Retinal Disease
Glenn J. Jaffe, Paul Ashton, P. Andrew Pearson in Intraocular Drug Delivery, 2006
Numerous in vivo studies have been performed with both gene expression markers and with therapeutic compounds. These have demonstrated the proof-of-principle of gene therapy for retinal disease. Studies evaluating onset, intensity, and stability of gene expression and efficiency of gene transduction have been performed using marker systems with bacterial LacZ–encoding β-galactosidase and with the jellyfish-derived gene-encoding GFP. These marker studies have proved extremely valuable in characterizing different vector systems with respect to potential clinical application. The physicochemical systems such as the addition of certain lipid vehicles to the recombinant DNA and ballistic delivery of DNA-impregnated gold particles (gene gun) have generally been found to be limited by poor transduction efficiency and transient gene expression (6). Recombinant viruses demonstrate much more favorable profiles with respect to intensity and duration of expression and therefore have received the most attention vis-a-vis clinical application. Marker studies have defined fundamentally different characteristics regarding expression onset, tissue tropism, and stability of expression—see Table 1.
GOLD: human exposure and update on toxic risks
Published in Critical Reviews in Toxicology, 2018
Technology developed in the University of Wisconsin highlights a “gene gun” which was claimed to fire a DNA-tipped gold bullet to inhibit growth of murine tumours (Franklin 1965). This novel therapy was designed to alter the genome of cancers cells thereby making them susceptable to destruction by the body’s own immune system. Genes prepared using conventional cloning were then precipitated onto gold beads (1 nm) which were injected into tumors by a pulse of compressed helium. At the time, Professor Karol Sikora of Imperial College, London is reported as saying that “gene therapy is designed to get the foreign DNA to the right place. The gene gun is one of a number of approaches, each of which has advantages and disadvantages”. Sikora saw the gene gun as an interesting approach. Whilst gold has no clear action as a cytotoxic agent here, it is biocompatible in the human body and is potenially valuable as an anticancer therapy (Tiekink 2008; Powell et al. 2010; Paciotti et al. 2004; Gasull 2012; Murawala et al. 2014).
Immunization with plasmids encoding M2 acetylcholine muscarinic receptor epitopes impairs cardiac function in mice and induces autophagy in the myocardium
Published in Autoimmunity, 2018
Karla Consort Ribeiro, Roberto Perez Campelo, Daniela del Rosário Flores Rodrigues, Elisabete C. Mattos, Izaira Trincani Brandão, Célio Lopes da Silva, Eliete Bouskela, Camila Guerra Martinez, Eleonora Kurtenbach
Immunizations were performed using a helium-driven gene gun (Bio-Rad, Hercules, California, USA). DNA-coated particles were prepared by mixing 25 mg of 1.6 μm gold microcarriers with 100 μl of 0.05 mol/L spermidine containing 50 μg plasmid DNA and 1 mol/L CaCl2 (100 μl). After precipitation and washing, the mixture was loaded into tubing and dried. As a result, each cartridge contained 1 μg of plasmid DNA. The DNA was delivered into the shaved ventral region of each animal with a discharge pressure of 400 psi. Mice from both groups were primed and boosted three times with a 14-day (2 weeks) interval between boosts, with the first set of immunizations indicated as zero in the timeline. The immunizations were repeated 23 weeks following the first three boosts (see Figure 1, second black arrow in the upper panel for details).
Modern vaccine strategies for emerging zoonotic viruses
Published in Expert Review of Vaccines, 2022
Atif Ahmed, Muhammad Safdar, Samran Sardar, Sahar Yousaf, Fiza Farooq, Ali Raza, Muhammad Shahid, Kausar Malik, Samia Afzal
The major strategies used to produce plant-based vaccines are nuclear, transplastomic, and viral vector transformation. Nuclear transformation is a very simple and widely used method because the foreign antigen is inserted into the nuclear genome. Agrobacterium tumefaciens or gene gun-mediated transformation is used for gene transfer. The nuclear transformation results in the continuous production of recombinant proteins. Additionally, nuclear transformation also results in the post-translational modification that takes place in eukaryotic systems [93,94]. But it is also coupled with some disadvantages including, lower expression level, gene silencing, position effect, and a chance of contamination. The chloroplast transformation overcomes some of the drawbacks of nuclear transformation, which has hampered commercialization as a plant-based recombinant vaccine. The desired gene (for an antigen) is directly introduced into the genome of the plant chloroplast by using a particle cannon. Most of the currently reported edible vaccines were produced by this method because of the high stability in gene expression. In chloroplasts, many viral antigens like rotavirus and canine parvovirus were expressed. Through overcoat and epic at technologies, several viruses such as cowpea mosaic virus (CPMV), alfalfa mosaic virus, tobacco mosaic virus (TMV), cauliflower mosaic virus (CaMV), tomato bushy stunt virus, and potato virus are designed to express the part of antigenic protein on their surface as reviewed in [95].