Study and evaluation of HfO2 hollow microneedle structure based on structural mechanics and fluid dynamics analysis
Objective The structural mechanic of HfO2 hollow microneedles (HMN) with different tip sizes and the hydrodynamic properties of HfO2 hollow microneedles were investigated in order to enhance the penetration performance of HfO2 hollow microneedles,to minimize the loss of liquid drug during drug delivery,and to improve the precision of drug delivery by hollow microneedles.Methods Nine combinations of HMN dimensions were obtained by orthogonal design for the length (L=250μm,350μm,and 500μm),diameter (Db=150μm,200μm,and 250μm),and tip diameter (Dt=10 μm,20 μm,and 30 μm) of the HfO2 hollow microneedles,and the optimal shape of the hollow microneedles was analyzed by structural mechanical analysis.The hydrodynamic analysis was carried out for the three shapes of T-shaped,120° Y-shaped and 60° Y-shaped luminal orifices.Under different inlet pressures,the pressure and velocity distributions of the fluids inside the three lumens were investigated,and the fluid velocity losses of the three lumens were analyzed to quantitatively evaluate the flow performance in the lumen.Results The structural mechanical analysis of nine groups of HfO2 hollow microneedles showed that with a microneedle length of 350 μm,a base diameter of 200 μm,and a tip diameter of 20 μm,the HfO2 hollow microneedles were able to obtain a high safety coefficient and maintain the structural stability,and did not experience any failure during the puncture process.The fluid dynamics study of the HfO2 hollow microneedle showed that the velocity loss from the inlet to the outlet was minimized for the 60° Y shaped HfO2 hollow microneedle lumen.Conclusions The HfO2 hollow microneedle designed in this paper can optimize the puncture performance while meeting the safety requirements,as well as reduce the flow velocity loss and realize the non-clogging drug delivery,which provides guidance for the subsequent reduction of the cost and time associated with the experimental study.
hollow microneedlecomputational fluid dynamicfinite element analysistransdermal drug delivery
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