| Since the mesoporous silica was reported at 1990s,it has motivated researchers in various fields as a novel inorganic material.Mesoporous silica has great potential in drug delivery system with its unique advantages such as mesoporous channels,high specific surface area,nanoparticle size and so on.It is essential to control the porous diameter in mesoporous silica when it was applied in drug delivery.This paper focuses on the preparation and application of mesoporous silica.Mesoporous SiO2 particles with larger pore size are used as drug carrier to release antibiotic.The obtained antibacterial nanoparticles are combined with sodium alginate to fabricate wound dressing with antibacterial and sustained-release properties.The main research is as follows:（1）By using stearyltrimethylammonium bromide（STAB）as the structure directing agent,mesoporous silica particles are synthesized through sol-gel method.The influence of raw ratio and process parameters on structure and particle size distribution of silica are discussed.Laser scattering particle analyser,fourier transform infrared spectroscopy,transmission electron microscopy,nitrogen adsorption analyser and X-ray diffraction are used to characterize the meso-structure and morphology of mesoporous SiO2 nanoparticles.The results show that mono-dispersed mesoporous with large pore size about 3.2 nm and particle size about 172.4 nm were prepared successfully.（2）Mesoporous silica loaded ciprofloxacin hydrochloride nanoparticles（LS）are prepared with the mesoporous silica as solid support and ciprofloxacin hydrochloride（CH）as antibacterial component.Not only the nature of interaction between the drug and host,but also the release property of CH are studied under different pH conditions.Zeta potential results confirm there is electrostatic interaction between guest molecule（CH）and mesoporous SiO2 material,and the appropriate concentration of impregnating solution can make the best use of CH to achieve high drug loading rate and entrapment efficiency of LS.CH molecules are released more rapidly in acid condition about 26.63%than in neutral environment about 15.74%in first hour.Different release models were adopted to describe release kinetics mechanisms,and the release rule conformed to the Ritger-Peppas model significantly.（3）The antibacterial nanoparticles are mixed with sodium alginate solution（SA）by solution blending method which can become calcium alginate（CA）after ion exchange process,then wound dressing named CA-LS with long-term antibacterial function are prepared through freeze-drying method.The CA-LS dressing shows a uniform,flat and spongy appearance.By comparing with CA sponge,there is no significant decrease in hydrophilicity CA-LS dressing,and the strength of CA-LS dressing increased.Drug release experiment shows that the CA-LS dressing can keep slow release of the CH within 36 h without burst release with certain pH sensitivity.（4）The clotting experiment shows that CA-LS sponge has no effect on coagulation,which means that CA-LS dressing still retains a good hemostatic effect in vitro.Antibacterial experiment shows that CA-LS dressing has antibacterial effect on both Escherichia coli and Staphylococcus aureus Sustained antibacterial result shows that CA-LS dressing displays potential in prolonging antibacterial time and enhancing antimicrobial effect. |
