The Effects Of Electrospun Nanofibers Loading Astragalus Polysaccharides On Osteoblast Cells

Objective: Preparation of astragalus polysaccharides (AP) electrostatic spinningslow-release fiber.According to investigating the in vitro release of slow-release fiberand its effect on cell adhesion, cell proliferation and cell differentiation, preliminarydiscussing the feasibility of repairing peri-implant bone defects in AP.Methods:Preparing different concentrations (0μg/ml,25μg/ml,50μg/ml,100μg/ml)of the AP and Poly-L-Lactide (PLLA) by emulsion method (W/O) as W/O emulsion,Using electrostatic spinning propulsion to prepare electrostatic spinning apparatusPLLA (AP:0μg/ml), PLLA/AP1(AP:25μg/ml), PLLA/AP2(AP:50μg/ml),PLLA/AP3(AP:100μg/ml) sustained release fibers. Using a scanning electronmicroscope (SEM) to observe the appearance characteristics of electrospinning.Periodically extracting the PLLA/AP1, PLLA/AP2, PLLA/AP3when the1st,3rd,5th,7th,9th,11th,13th,15th,17th,19thand21thday, developing color with phenol-sulfuric acid, measuring AP absorbance at490nm by Ultraviolet spectrophotometry,determining PLLA/AP1, PLLA/AP2and PLLA/AP3in vitro release kinetics anddrawing in vitro release profiles; Using fluorescent microscope to observate thesituation of osteoblast adhesion on the PLLA/AP with propidium iodide(PI) byfluorescence tagging.Using MTT to measure the absorbance(A) at570nm byELIASA, to detect the proliferation of PLLA, PLLA/AP1, PLLA/AP2, PLLA/AP3onosteoblasts.Measuring alkaline phosphatase (ALP) absorbance values at520nm byELIASA,by calculating ALP activity according to ALP kit instructions, to test thedifferentiation of PLLA, PLLA/AP1, PLLA/AP2, PLLA/AP3on osteoblasts.Results: Observing the appearance of PLLA fiber by SEM,it is visible that continuousfiber,much space between each other and surface smoothing. PLLA/AP fibers werecrisscrossed three-dimensional porous network and Long-short network structure andfiber adhesion degree and diameter uniformity reduced.There is no obvious change ofthe effect of the concentration of the AP on the morphology of the fibe. The first day,0.2g composite scaffold can release about40%of the AP.The first week,the drugrelease fast and be able to release about75%of the AP. Then it releases rate slowdown and about90%of the drug will be released until the22th day.It is observed that within the first24h, The release of the AP presents a state of sudden release.Later, therelease of the AP is smooth and slow.It is visible by fluorescent colouration that theosteoblast adhesion in fiber membrane growth, cells combined with stent; The role ofpromoting cell proliferatio in PLLA/AP2and PLLA/AP3groups was statisticallysignificant (P <0.05). PLLA/AP1group acting on osteoblast until the48th hour,therole of promoting cell proliferation was statistically significant (P <0.05).LLA/APincrease the osteoblast ALP activity significantly (P <0.05).Conclusion: This study shows that the load of AP slow-release fiber prepared byelectrospining, has certain ability of slow release.The surface may be adheredosteoblast cells and have an effect of promoting cells differentiation. The preparationprocess is simple and easy to store, so it is expected to apply to repair the elderlyperi-implant bone defects.