Particle acceleration for delivery deoxyribonucleic acid vaccine into skinin vivo

Skin represents an important immunogenic inductive site, 3%-4% epidermis ce lls are special antigen-presenting cells. Deoxyribonucleic acid (DNA) vacci ne can elicit vigorous immune responses in epidermis cells. The means of de livering DNA vaccine into epidermis cells becomes an important step in DNA vaccine applications. This article presents a new type of gene gun based on the principle of two-stage injector acceleration. DNA coated particles are attached on an screen-type carrier located at the negative pressure inlet, the particles will be sucked into the accelerating channel by negative pre ssure and be accelerated at a great speed. FLUENT, a computation fluid dyna mic application software is used to simulate the flow condition of the inje ctor. Distribution of Mach number, total pressure on exit cross section, an d negative pressure on negative pressure inlet are analyzed, by which the p rocess of acceleration of particles is determined. We also measured these p arameters in this study. The data show that the particle velocity can be up to 500 m/s and the particles distribute evenly over a circle of Phi 20 mm. The numerical simulation results coincide with experimental data well. The refore, the results of numerical simulation can be served as guidance for a n optimal design of the gene gun and for practical operations. When gene co ated particles are distributed evenly, they can penetrate into or even thro ugh epidermis cells where the gene can be expressed and subsequently elicit s host immune responses. This device may be evaluated in human objects in f uture. (C) 2001 American Institute of Physics.