Micro/nano Scaled Drug-loaded Fibers Via Near-field Direct 3D Printing

The design and preparation of two-dimensional(2D)or three-dimensional(3D)fabricated micro/nanofibers structures has gained appreciable interest in recent times,particularly for drug delivery system.It is essential to achieve structures wherein drug stability,loading capacity and the desired controlled release profile can be achieved.Electrohydrodynamic(EHD)direct-writing has gained widespread interest as a potential technique to fabricate micro/nanofibers for biomedical applications as it offers flexibility in material selection,low cost,and ability to construct complex 2D or 3D structures.This study mainly fouses on fabrication and characterization of 2D or 3D micro/nanofibers for drug delivery via Electrohydrodynamic direct-writing.We aim to print various 2D or 3D structures by controlling the X-Y-Z motion platform and optimize the operated parameters.In additon,the drug loading and controlled release of printed 2D or 3D micro/nanofibers were evaluated.The study improves the release behavior of disordered drug-loaded fibers prepared by traditional electrospinning.A selection of polyvinyl pyrrolidone(PVP)/polyethylene oxide(PEO)composite fiber 2D patterns were first fabricated to examine EHD printing potential.Printing parameters were assessed for their impact on fiber diameter.Fourier-transform infrared spectroscopy(FTIR)analyses revealed PVP-PEO blend behavior and also the incorporation of the active into the polymeric matrix.The release of tetracycline hydrochloride(TE-HCL)from patterned structures reached 5 h which is comparable to existing polymer based matrix systems.In order to print 3D micro/nanofibers structures,electrohydrodynamic(EHD)printing technique was developed to fabricate TE-HCL patches using polycaprolactone(PCL)and a composite system(PVP-PCL).The effect of various operating parameters on fiber deposition and alignment was explored.FTIR demonstrated PCL-PVP blend behavior and successful encapsulation of TE-HCL.Patches prepared using PVP and TE-HCL displayed enhanced hydrophilicity.Tensile tests confirmed that mechanical properties can be varied by the incoporation of PVP and TE-HCL.Release of antibiotic from PCL-PVP composite was slower when compared to pure PCL or PVP systems.The printed patch pore size also resulted in antibiotic release behavior.On the basis of the above experiment,we further used one-step coaxial electrospinning process to fabricate 2D or 3D micro/nanofibers,with PVP as the core and PCL as the shell fluid.A selection of 2D or 3D patterns were fabricated indicating the coaxial electrospinning process printing potential.In addition,the dual needle co-jetting in EHD printing provide a versertial 2D or 3D micro/nanofibers fabrication.The operated parameters were optimized and the release profile of the dual dye(Rhodamine B and Acriflavine)from the printed structures were obtained.The obtained 3D fiber stuctures were characterized by mechinal,physical,and in-vitro release test.Experimental results demonstrate that EHD direct-writing provids an effective method to fabricating 2D or 3D micro/nanofibers for drug delivery system.