Development of needle-free jet with twin-fluid atomization processes

This paper investigates the development of the integrated twin-fluid micro-injector (IMA) to enhance the atomization performance and its penetration through the collagen gel with high speed micro-spray. Results showed that the IMA-type micro-injector produced the needle-free jets with diameter ranging from 23μm to 97μm depending on the gas pressure. It might be used to replace the metal needles for drug delivery through the skin. Results also found that the penetration of the micro spray to the collagen gel depends on the property of the working medium and the power of the impinging spray jet. The jet of single phase of gas flow did not result in the penetration into the collagen gel because its impinging power was less than the liquid phases. The working fluid with 5% levorotary C solution was more effective in the penetration test because of its surface reaction with collagen gel. The induction period and the break period were significantly reduced due to the higher injection power under the second injection mode. The maximum penetration depth was reduced for the collagen gel with higher concentration because the Young's modulus of the collagen gel increased with the higher collagen concentration.