Synthesis Of Phosphate Nanomaterials And Its Application As A Drug Carrier

Phosphate nanomaterials(ACP,HAP,OCP)are important biominerals,which function as supporting,protecting and cutting role in vivo.They also have many physical and chemical properties,such as low density,large specific surface area,low toxicity,excellent biocompatibility and biodegradablity.They can be utilized as drug carriers,bioceramics and bone repair materials in the biomedical fields.In this paper,two phosphate materials have been synthesized and applied as drug carries to study the effect of drug delivery.Firstly,the cationic polyelectrolyte-polypropylene ammonium chloride(PAH)was used as the crystal growth modifier,to synthesize HAP porous microspheres in the hydrothermal reaction.The resultant porous microspheres have high specific surface area and excellent biological compatibility,which can serve as drug carriers.The adsorption/desorption of ibuprofen(lm-ibu)drug,pH-response characteristics have been studied.Secondly,the ACP/PAA mineral hydrogel has been synthesized,which is composed of calcium phosphate(ACP)nanoparticles physically crosslinked polyacrylic acid(PAA)molecules.Some basic properties such as viscosity,plasticity,malleability,self-healing,reversibility,shear thinning and thixotropic properties have been explored thoroughly.When the thermochromic materials of PBAs was introduced into the hydrogel matrix,the reversible thermochromic ACP/PAA/PBAs composites could be produced.Due to the non-toxicity and excellent biocompatibility,ACP/PAA mineral hydrogel is also a good drug carrier,which shows high loading and slow release effect of Dox.The detailed results were listed as follows:1)The porous hydroxyapatite microspheres have been produced in the low PAH concentrations of 0.3-0.5 g/L after the hydrothermal reaction of 12 h.Three growth processses are included:(I)the organic "vesicle" aggregation,(II)heterogeneous nucleation and(III)phase tranformation.PAH could effectively promote the heterogeneous nucleation of amorphous calcium phosphate on the surface of organic "vesicle",the regular arrangement of HAP,and the preferred growth of nanorods in the < 002 > direction.HAP nanorods with adsorbed PAH molecules on theri surface interact hydrogen bonds and arranged regularly into porous microspheres.These porous microspheres have low density,large specific surface area,high stability,strong surface infiltration ability,low toxicity and good biocompatibility,which can effectively control drug release as needed.The loading capacity of prouous HAP is about 413.65 mg/g after 24 h adsorption of IBU.When the release time exceeds 60 h,the cumulative release rate of the drug maintained at about 64.95% and don’t change with time.Meanwhile,HAP/IBU displays a higher release rate in PBS solution(pH=7.4)with the increase of sustained release time.2)The ACP/PAA mineral hydrogel has been synthesized by physical crosslinking of the polyacrylic acid(PAA)and calcium phosphate(ACP)precursor solution in the mild aqueous solution.The hydrogel has some basic properties such as plasticity,malleability,self-repair,reversibility,shear thinning and thixotropic properties.More importantly,the reversible thermochromism materials of PBAs can be introduced into the hydrogels and form the hybrid films with different thickness.Simultaneously,the hybrid films show reversible color change within a very short time under the temperature of 120℃.In addition,the gel with good biological compatibility and non-toxicity can be applied as a drug release carrier for biological and clinical medicine.The Dox loading of hydrogels is 764 mg/g.The hydrogel will dissolve in different pH phosphate buffer(pH=7.4,5.6,4.5)in 30 minutes.The Dox release rate of ACP/PAA/Dox is as high as 97.25% in the phosphate buffer(pH 7.4).Therefore,it can be used as an excellent target drug for the treatment of cancer.