Layer-by-Layer Assembly Of SA/PEI Micorcapsules And Application On Paper Products

Microcapsule is a material that can be used to enclose solids,liquids,or gases inside a wall made of hard or soft soluble film,in order to reduce dosing frequency and prevent the degradation of drugs.Compared to other micro delivery system,microcapsules possess many excellent qualities like high stability,longevity,various methods to encapsule different substance and can respond to environment changes if prepared by certain materials.The application of microcapsules are restricted by their large size,and nowadays microcapsules are prepared by artificial polymers normally,but natural polymers like alginate are more competitive in medical area due to their nice biocompatibility and biodegradability,thus studying on small sized natural microcapsules can point out a new research direction to the highly developed microcapsule technology.In this study,a novel nano-sized microcapsule was prepared through layer-by-layer(Lb L)assembly,using calcium carbonate nanoparticles as the sacrificial inorganic template and sodium alginate(SA)and polyethyleneimine(PEI)as the wall material.Ciprofloxacin,as an antibacterial medicine,was selected as the model drug to study the encapsulation and release properties of the microcapsules,the change of paper properties were characterized after the absorption of microcapsules.(1)Single factor experiments were designed to decide the optimal dispersion conditions for calcium carbonate nanoparticles.The mean size of calcium carbonate template was reduced to 478 nm after dispersing under these conditions: SDS concentration 0.05mg/mL,CaCO3 concentration 20mg/mL,dispersion time 40 min,no string steps.SEM,TEM and AFM showed that the prepared microcapsules have a diameter under 100 nm,typical creases and collapse were found on the surface of the microcapsuels.FTIR and element analysis showed that sodium alginate and PEI were successfully assembled on the surface of template by electrostatic force.(2)The nano-sized SA/PEI microcapsules showed high loading capacity of ciprofloxacin under conditions of long loading time and drug concentration,the loading capacity of microcapsules increased compared to other large sized microcapsules.FTIR results showed that the loading of ciprofloxacin in microcapsules was driven by electrostatic force.SA/PEI microcapsules can maintain the activity of loaded ciprofloxacin,the release ofciprofloxacin from microcapsules took on a sustained release.(3)The whiteness and mechanical properties were decreased after the absorption of microcapsules due to the acidity of microcapsule suspension and the influence of microcapsules on hydrogen bond between fibers,drug loaded microcapsules showed stronger influence on the mechanical properties.The absorption of microcapsules also reduced the thermal stability of paper.The antimicrobial efficiency of SA/PEI microcapsule paper increased from 22.1% to 40.8%,antimicrobial efficiency of drug loaded microcapsule paper increased from 46.7% to 86.3%,with the increase of microcapsule concentration.