Design And Analysis Of A Novel Anti-shedding Combined Soluble Microneedle

Micro-electro-mechanical system(MEMS)which emerged in the 1980 s is a popular technology involving a variety of disciplines such as mechanics,optics,calorifics,electricity and magnetics,with the most notable features being their small size,light weight and low power consumption.At present,microelectro-mechanical system has been widely used in various fields,among which intelligent microneedle system based on micro-electro-mechanical system has significant research significance and far-reaching development prospects.As one of the most promising third-generation transdermal drug delivery technologies,microneedle has outstanding advantages over traditional oral and injectable drug delivery and can achieve painless and minimally invasive drug delivery.In addition,the combination of hollow microneedle with intelligent systems can also meet more complex medical needs,such as continuous controlled drug delivery,body fluid and blood extraction.However,conventional hollow microneedles are subject to the risks of needle tip breakage,skin tissue blockage of the needle opening and lateral drug leakage,and how to avoid these risks has become an important research direction for hollow microneedles.In this thesis,a new solution is proposed using a combination of a soluble needle tip and a hollow needle body in an attempt to provide a new solution.The thesis begins with a review of developments and trends in transdermal drug delivery and microneedle,with a detailed analysis of existing microneedle structures,materials and processing methods.On this basis,the concept of the novel anti-shedding combined soluble microneedle is proposed,which has a soluble solid conical tip and an insoluble hollow cylindrical body.When the microneedle is pierced into the skin,the soluble tip rapidly dissolves in the skin,leaving the hollow microneedle for drug delivery and fluid extraction,perfectly solving the problems of broken tip,blocked needle opening and side leakage of conventional hollow microneedle.As the tip of the microneedle may become detached before penetrating the skin,a groove is added to the upper periphery of the needle body to strengthen the bond between the tip and the needle body,and the novel combined microneedles can prevent the soluble needle tip from detaching during use or transportation.At the same time,the microneedle was dimensioned to allow for the extraction of not only body fluids but also blood.Subsequently,by analyzing the materials,mechanics,pain sensation,and blood extraction of the microneedle,the material,length,and the range of other parameters of the microneedle was determined.Using ANSYS finite element analysis software,the effect of the inner and outer diameters of the microneedle on the maximum stress and deformation of the microneedle under 10 times the penetration force(31.8 MPa)was investigated,and the inner and outer diameters of the microneedle were determined.On this basis,the effect of groove height and groove diameter on the maximum stress and deformation of the microneedle was further investigated and the relevant parameters of the groove were determined.Finally,in combination with other factors,the specific structure of the microneedle was determined and the microneedle body was modelled and simulated.The results show that the novel antishedding combined soluble microneedle has good mechanical strength and stability;the tip is bonded to the body with high strength and the tip does not fall off.For hollow microneedles,the flow pattern of the fluid is also very important,so the novel anti-shedding combined soluble microneedle were analysed in fluid theory and simulated in ANSYS using the fluent module.Firstly,the flow rate of the microneedle was simulated and the results showed that the flow rate of the microneedle increased linearly with the inlet pressure.Secondly,the flow velocity distribution and pressure distribution of the liquid inside the microneedle in the XY,YZ,XZ planes as well as in the X,Y and Z axis directions at the centre of the microneedle were analysed,and the results showed that the liquid flow inside the microneedle exhibited a laminar flow state.A detailed arrangement of the processing of the novel anti-shedding combined soluble microneedle is then presented.Finally,an outlook on the development of smart microneedle systems is given.The proposed novel anti-shedding combined soluble microneedle addresses the problems of traditional hollow microneedles and is expected to bring the application of hollow microneedles to a new level.In addition,the application of the novel anti-shedding combined soluble microneedle will certainly promote the development of intelligent microneedle systems and bring about a great change in micro-medical devices.