The Release Of Microneedle-Included Drugs And Adherent Cell Based On Layer-by-Layer Self-Assembled Multilayer Film

Layer-by-Layer(LBL)self-assembly is a technology that has emerged in the last two decades to form a self-assembled multilayer membrane system by means of weak interaction between molecules,such as electrostatic interaction,hydrogen bond,coordination bond,and so on.LBL has simple operations,not high requirements for the preparation of environment and equipment requirements,and has very wide selection of self-assembled substrates,it is a simple and efficient way to build multilayer film on the base.Based on the advantages of the self-assembly technique,this paper attempts to expand the application of self-assembly techniques in the direction of drug sustained release and the adhesion and nondestructive release of microacupuncture.The main contents of this paper include:1.Using LBL self-assembly to Construct Multilayer Film on the Surface of Microneedle to Prepare the Drug-loading Microneedle.Microneedle is a tiny needle with a height of only a few hundred micrometers.Due to its special shape characteristics,it shows a broad development prospect in the application direction of percutaneous medicine.In this paper,doxorubicin micelles were loaded on the surface of poly(lactic acid)microneedles via layer by layer self-assembly technology for preparation of pH-responsive drug-loaded system.The drug-loaded microneedles can be assembled into doxorubicin micelles under acidic conditions and released under physiological pH conditions.In this paper,starting from the preparation of doxorubicin micelles,the morphology and particle size of the micelles were characterized by transmission electron microscopy(TEM)and Malvern laser particle size analyzer.After the micelles were assembled on the microneedles,the drug-loaded microneedles were characterized using a laser confocal microscope(CLSM),and it was seen that the micelles were uniformly distributed on the surfaces of the microneedles.At the same time,the drug release kinetics study was also carried out.UV-Vis spectrophotometer(UV-Vis)test results showed that the complete drug release time was extended from 2 hours to 24 hours after heating and crosslinking at 105? for 10 minutes.2.Preparation of near-infrared(NIR)light-responsive Free-standing Multilayer Films with Upconverting Nanoparticles.Upconversion nanoparticles(UCNPs)are special materials that can emit local UV light under NIR excitation.In this chapter,I will cover UCNPs with poly(dimethylsiloxane)(PDMS)to prepare flexible,free-standing PDMS/UCNPs hybrid membranes.The azobenzene(Azo)multilayer film was fabricated on the hybied film using the LBL self-assembly method.The rhodamine-B-linked ?-cyclodextrin monothiol(?-CD-RhB)was loaded as a model drug onto the membrane by complexation.Under biocompatible NIR irradiation,the film emits local UV light,which triggers the trans-cis isomerization of the Azo units on the membrane to release the drug.We used UV-Vis to characterize the process of film growth.After loading ?-CD-RhB,the composite film changed from yellow to red.After cleaning the pattern,it was irradiated with NIR for half an hour.After that,it was clearly found that the area covered by the pattern remained red.Uncovered areas revert to yellow,verifying that the model drug can be released under NIR irradiation.3.Capture/Release Breast Cancer Cells(MCF-7)Using Near-Infrared(NIR)Light-Responsive Hybird Membrane.Achieving dynamic regulation of cell-surface interactions is especially attractive for tissue engineering and cell-based treatment.This chapter combines the work of the previous chapter with the use of hybird membranes for the capture and release of MCF-7.The hybrid membrances is connecting the anti-epithelial-cell adhesion-molecule(EpCAM)antibody by ?-cyclodextrin monothiol(SH-?-CD)and 4-maleimide butyric acid N-hydrosuccinimide ester(GMBS).Capture MCF-7 using EpCAM specific binding to MCF-7 cell surface antigens.NIR light is used to excite UCNPs and converted into local UV light,leading to a rapid release of cells above via the trans-cis isomerization of the azo units.Specifically,this process results in a rapid release of an entire cell-antibody-streptavidin complex from the functionalized surface,without disrupting cell-surface receptor.Multimaterials systems contribute a functional combination of optical conversion and capture/release,in which PDMS membranes also acting “firewall” to separated UCNPs and photo-responsive coating.Such a design can effectively avoid unwanted non-antibody-based capture and local over-heating,thereby achieving a high release efficiency and cell viability.This dynamic control of cell adhesion/release with an integrated composite membrane can provide new inspiration for constructing functional nano-biological interfaces.