Patterning Multi-nanostructured Poly(L-lactic Acid) Fibrous Matrices To Precisely Manipulate Biomolecules Distribution And Functions

It is well known to all that controlling the distribution and functionalization of biomolecules precisely play a very important role in biomedical engineering and regenerative medicine.The micropatterning techniques that have emerged in recent years provided a way to regulate the distribution and function of biomolecules precisely by controlling the chemical composition and microstructure of the material,However,the currently used micropatterned substrates tend to be inert or poorly biocompatible materials such as PDMS or silicon wafers which limited the applications of the micropatterning techniques in the regulation of the distribution and function of biomolecules to some extent.Electrospinning is widely used in tissue engineering and regenerative medicine due to its advantages of simple operation,large specific surface area,continuous production of nanofibers and the simulation of natural extracellular matrix structure.Our group combined the electrospinning and micropatterning technology fabricated the micropatterns of PLLA nanofibers on the glass substrate.However,the current applications of this method in biomedical engineering has not been further studied.In view of this,this work further use of advanced electrospinning fabricated and micropatterned PLLA nanofibers containing silver nanoparticles,PET / PLLA bicomponent fibers and hollow PLLA fiber,the aim is to create a system that controlling the distribution and functions of biomolecules.The specific research contents are as follows:First,In order to control the distribution of the live/dead bacteria,we add the silver nanoparticles to functionalized the PLLA nanofibers,then the collected fiber membrane was micropatterned by agarose hydrogel stamps,the etched part is the glass substrate while and non-etched part is PLLA nanofibers containing silver nanoparticles,thereby forming the micropatterned regions with different compositions.After seeding E.coli on the samples,the results showed that bacteria grew well in the etching part and almost no dead bacteria appeared,while the number of dead bacteria in the non-etched part increased obviously which indicated that we could control the amount of silver nanoparticles to control the live/dead distribution of bacteria.Second,forcontrollingthe distribution of cells,we used side by side electrospinning prepared PET / PLLA bicomponent fibers,then the collected bicomponent fiber membrane was micropatterned by agarose hydrogel stamps,due to the trifluoroethanol solution can only etch PLLA so the etched part is PET fibers while the un-etched part is the bicoponent fiber and thereby forming the micropatterned regions with different compositions.Taking mouse bone marrow mesenchymal stem cells as an example we found that the cells always preferentially adhered and proliferated in the etched area which indicated that we can control the regional distribution of cells by this method.Last,so as to control the adsorption and release of protein,we used the coaxial electrospinning fabricated PLLA hollow fiber,the collected oriented PLLA hollow fibers were micropatterned in the same way to control the hollow fiber length and studied the protein adsorption and release behavior.Taking standard BSA protein as an example,the adsorbing protein ability of solid and hollow fiber was compared and studied the rate of release of BSA protein from PLLA hollow fibers of different lengths.The results showed that the adsorption protein capacity of PLLA hollow fiber is stronger and the longer hollow fibers have a sustained release effect and thus released more durable.