Three Dimensional Molding,Physical Property Control And Application Of Hydrogel Microneedles

Delivering drug into injured human body part safely,efficiently and keeping the whole process controllable is important to the recovery of injured human tissues.Percutaneous drug delivery could avoid the first pass effect caused by gastrointestinal administration effectively.Drugs enter the human blood circulation through subcutaneous capillaries directly which reducing the direct metabolism of drugs that have not yet functionalized in targeted area in liver.However,the permeation efficiency of drugs is still a major limitation of percutaneous drug delivery.In order to improve the efficiency of transdermal drug delivery,microneedle transdermal drug delivery method has been proposed in recent years.Comparing with traditional injection drug delivery,it has a series of advantages,such as painless and minimally invasive.As a result,microneedle has become a hotspot in percutaneous drug delivery.Microneedles in this paper are based on hydrogel,which has the characteristic of absorbing the interstitial fluid of skin rapidly and forming a continuous channel when they are inserted into skin.In addition,digital stereolithography 3D printing technology is utilized during the preparation of hydrogel microneedles.This paper presented the three-dimensional molding,physical properties and application of microneedles based on hydrogel.The main work is as follows:The principle and characteristics of the existing microneedles and several mainstream 3D printing technologies are investigated,and a high-precision digital light processing 3D printing platform system is designed and developed.The application prospects of microneedles in transdermal drug delivery and the unique advantages of hydrogel microneedles in microneedles are introduced.The advantages and limitations of several mainstream 3D printing techniques were compared.This paper also introduces the hardware and software of building high-precision stereolithography platform.Debugging and applying this high-precision stereolithography platform are also presented.With the self-developed digital light processing printer,the hydrogel microneedles based on PEGDA were made under different printing parameters.As there is a balance between accuracy and stiffness,the experimental results show that 300 ms is the ideal exposure time for constructing PEGDA hydrogel microneedles after ample groups of mechanical tests and measurements.At the same time,the simulation experiments of artificial skin microneedle puncture and PEGDA hydrogel microneedle injection and drug extraction were completed.The results of drug injection and drug detection were analyzed quantitatively to provide some reference for the application of PEGDA hydrogel microneedle in biological injection and drug extraction.The research on microneedle response and intelligent operation by response verified the feasibility of making the hydrogel micro needle with changing the substrate.In this paper,two different materials were studied as the substrate of functional microneedle: one is based on composite PLA/PET film.The composite PLA/PET film can respond to near infrared and temperature,and the structure is thin and suitable for combining with sodium alginate microneedle relatively;the other one is based on TPU material and vascular channels were designed in TPU structure.The shape memory function of the base structure is realized by using the shape memory characteristics of TPU material.A system for controlling the local in-situ growth of micro-nanocomposites is also developed.Traditional monolithic composites as microneedle substrates have limitations such as large reaction area,poor controllability and limited function.In order to overcome this disadvantage and explore a new functional practice direction of hydrogel microneedles,we tried to develop this system to control the local in-situ growth of micronanocomposites,and look forward to applying this method to the fabrication of microneedle substrates in the future.Through the verification experiment of this system for controlling the local in-situ growth of micro-nanocomposites,the application feasibility of the system for controlling the local in-situ growth of micro-nanocomposites is verified.