Preparation And Characterization Of Porous Silicon Embedded Curcumin As New Delivery Vehicles

Curcumin has a wide range of biological activity.It is a kind of low-price,high-efficiency and low-toxicity natural polyphenols,and also a food function component with extensive usage.A large number of studies have shown that curcumin contains antioxidant,anticancer,and antibacterial bioactivities.However,low water solubility and low bioavailability greatly limits its usage in health food and clinic.Recently,porous silicon,due to its unique advantages such as large specific surface area and volume,good chemical stability,controllable size and nanopores and easy to be modified,is widely used as the carrier of refractory material.This paper,for the first time,uses porous silicon as a new carrier of curcumin,and also studies how curcumin,no-load porous silicon(PSi)and porous silicon with curcumin(PSi-Cur)effect the cancer cell toxicity and bacteriostatic.Provide relevant information for the application of curcumin in the field of food and medicineThe main conclusions are as follows:1.porous silicon film is prepared by electrochemical etching,observed with high-resolution thermal field emission scanning electron microscope,porous silicon film is dark brown,its particle size is 25?m and pore size is 20nm on average.2.The factors that may affect the loading of curcumin were studied.We found temperature,loading method and porous silicon treatment have huge impact on curcumin's encapsulation efficiency.10mg fresh dry porous silicon is etched for 600 seconds with 360 mA current.Adding 1mL Curcumin liquor and 1mL sodium nitrite solution(25mM),then static water bathing it with 50? water for 16 hours.Curcumin encapsulation rate is 71%on maximum.The amount of curcumin loaded on the porous silicon is 70?g/mg and curcumin loss rate is 14%.Recovery ratio and precision meet the requirements of sample analysis quality control.Within 4 hours,the average cumulative release rate of Curcumin is 93%.However PSi-Cur particle's release rate is 33.75%within 10 hours.This shows that the porous silicon has sustained effect.3.Within a certain range,with the increasing concentration of curcumin,PSi particles and PSi-Cur particle,the toxic effects on HT-29 cells and NCM460 cells are increasing.Porous silicon of low concentrations has no significant toxicity to HT-29 cells.While,if the concentration of porous silicon rises to a certain value,it have significant toxic influence on HT-29 cells.Curcumin and porous silicon have a synergistic toxic effect on HT-29 cells.When curcumin was loaded into the porous silicon,a low concentration of curcumin can achieve high toxicity on cell.When the concentration of curcumin is 5 ?g/mL,the fatality rate of HT-29 cell and NCM460 cell are 51%and 20%respectively.When the concentration of curcumin reaches to 10?g/mL,the fatality rate of HT-29 cell and NCM460 cell are 64%and 30%respectively.Meanwhile,PSi-Cur particles causes the death of 81%HT-29 cells at 125?g/mL(equivalent to concentration of 8.75?g mL curcumin)and 125?g/mL porous silicon can only case 21%HT-29 cell death.As to NCM460 cell,43%fatality rate was observed when PSi-Cur particles concentration was 125?g/mL.While 125?g/mL porous silicon can only cause 25%cell death.4.Using plate dilution method to determine of the minimum inhibition concentration of curcumin on Escherichia coli and Staphylococcus aureus.The results show that the minimum inhibitory concentration of curcumin for the two bacteria is related to the concentration of bacteria.The lower bacterial concentration,the lower drug concentration is needed for completely inhibitory effect.At a concentration of 106 CFU/mL of bacterial,curcumin with concentration of 500?g/mL can completely inhibit the growth of E.coli,but no significant zone of inhibition test.Which means curcumin is not sensitive to E.coli.300?g/mL Curcumin can completely inhibit the growth of Staphylococcus aureus.Its inhibition zone diameter is 11.13±0.19mm.Curcumin is rather sensitive to Staphylococcus aureus.PSi and PSi-Cur are not sensitive to E.coli and Staphylococcus aureus as well.