Microneedle-assisted microparticle delivery by gene guns: experiments and modeling on the effects of particle characteristics

Abstract

Microneedles (MNs) have been shown to enhance the penetration depths of microparticles delivered by gene gun. This study aims to investigate the penetration of model microparticle materials, namely, tungsten (51 mm diameter) and stainless steel (18 and 30 mm diameters) into a skin mimicking agarose gel to determine the effects of particle characteristics (mainly particle size). A number of experiments have been processed to analyze the passage percentage and the penetration depth of these microparticles in relation to the operating pressures and MN lengths. A comparison between the stainless steel and tungsten microparticles has been discussed, e.g. passage percentage, penetration depth. The passage percentage of tungsten microparticles is found to be less than the stainless steel. It is worth mentioning that the tungsten microparticles present unfavourable results which show that they cannot penetrate into the skin mimicking agarose gel without the help of MN due to insufficient momentum due to the smaller particle size. This condition does not occur for stainless steel microparticles. In order to further understand the penetration of the microparticles, a mathematical model has been built based on the experimental set up. The penetration depth of the microparticles is analyzed in relation to the size, operating pressure and MN length for conditions that cannot be obtained in the experiments. In addition, the penetration depth difference between stainless steel and tungsten microparticles is studied using the developed model to further understand the effect of an increased particle density and size on the penetration depth.

Penetration depth, concentration and efficiency of transdermal α-arbutin delivery after ultrasound treatment with albumin-shelled microbubbles in mice

“…Moreover, there are many reports on the delivery of large molecules using microneedles patch. In addressing this issue, microneedle delivery was used to enhance permeation flux of lidocaine hydrochloride and the penetration depths of microparticles delivered by gene gun (Nayak et al, 2014b;Zhang et al, 2013Zhang et al, , 2014. Moreover, optimized ultrasound combined with microneedles to further increase the permeation rates was proposed (Han & Das, 2013;Nayak et al, 2014a).…”

Microneedle‐Mediated Transcutaneous Immunization: Potential in Nucleic Acid Vaccination

“…[117] The MNs can create holes in the skin and allow microparticles to penetrate deep skin even at three bar. [118] Additionally, it is demonstrated that the combination of MN pretreatment and iontophoresis could improve the skin permeation of methotrexate, particularly in defatted skin. [119] Moreover, Li et al [120] fabricated an iontophoresis-driven porous MN array patch (IDPMAP) for the delivery of charged macromolecular drugs and the IDPMAP showed ≈99% skin penetration rate, which is considerably more efficient than a pristine MN array or iontophoresis.…”

The Rise of Polymeric Microneedles: Recent Developments, Advances, Challenges, and Applications with Regard to Transdermal Drug Delivery

“…After deciding on the proper physics and defining all of the parameters, the model should be simulated using computational software with suitable computer hardware configurations. Commonly used computational software include the updated versions of MATLAB and also COMSOL Multiphysics [ 79 , 80 ].…”