Fig. 4: Characterization of gas penetration depth of microorganism micro-engine microneedles (MM-MNs).
From: Microorganism microneedle micro-engine depth drug delivery
a Experimental diagram illustrating the detection of gas production from MM-MNs in simulated body fluids using a gas microelectrode system. Created with BioRender.com/e13d275. b Gas release from single microneedles loaded with different concentrations of glucose when immersed in simulated body fluid. c Test diagram of the penetration of MM-MNs through different skin thicknesses by using a transdermal test instrument. Created with BioRender.com/e13d275. d Trends in hydrogen gas concentration in simulated body fluid over time after penetrating different thicknesses of pig skin. Mean ± SD of n = 3 independent samples. e Experimental diagram of microelectrode real-time monitoring of subcutaneous gas concentrations at different depths. Created with BioRender.com/e13d275. f, g Trends in hydrogen gas concentration (f) and gas production rate (g) within the skin over time.
