Preparation and properties of silver-containing mesoporous silica-chitosan composites

Abstract

Objective To investigate the preparation method of silver-containing mesoporous silica nanoparticle-chitosan(Ag/MSN-Chi) composites and their microscopic representation, cytotoxicity, water absorption, rapid hemostatic properties and antibacterial properties. Methods Using ethyl orthosilicate as precursor and cetyltrimethylammonium bromide as porogen, silver ions were introduced into mesoporous silica nanoparticles (MSN) by ion-exchange method to prepare novel ordered silver-containing MSN (Ag/MSN) material with antibacterial action. Ag/MSN-Chi was prepared by using alkylated chitosan loaded with Ag/MSN. The experiment were divided into experimental group and blank control group according to the materials used. The experimental group was further divided into three subgroups: MSN group, Ag/MSN group and Ag/MSN-Chi group. The blank group was a positive control without material. The specific surface area, pore volume, pore size of MSN and Ag/MSN, the charge of Ag/MSN and Ag/MSN-Chi were calculated. The cytotoxicity, water absorption performance, hemostatic and antibacterial properties of MSN, Ag/MSN and Ag/MSN-Chi were evaluated by water absorption test, in vitro coagulation test and antibacterial test to calculate the relative cell survival rate, water absorption rate and prothrombin time (PT), activated partial thromboplastin time (APTT), and bacteriostatic rate. Eighteen healthy adult New Zealand white rabbits were randomly divided into three groups: control group (treated with medical gauze), Ag/MSN group (treated with Ag/MSN), and Ag/MSN-Chi group (treated with Ag/MSN-Chi), 6 rats in each group. A hepatic trauma hemorrhage model was established and the hemostasis time was calculated. Data comparisons were analyzed by analysis of variance and t test. Results The specific surface area of MSN was (523.8±12.4) m2/g, the pore volume was (1.2±0.4) m3/g, and the pore diameter was (3.5±0.9) nm; the specific surface area of Ag/MSN was (521.6±11.7) m2/g, the pore volume was (1.15±0.5) m3/g, and the pore diameter was (3.6±0.7) nm, there was no significant difference in specific surface area, pore volume and pore size between the two materials (t=0.224, 0.135, 0.015; with P values above 0.05). The Zeta potential of Ag/MSN was measured to be -19.7 mV, and the Zeta potential of Ag/MSN-Chi was 10.27 mV, indicating that the surface charge of Ag/MSN changed from a negative value to a positive value. The relative survival rates of Ag/MSN-Chi group, Ag/MSN group and MSN group at 1, 4, and 7 days after co-culture with mouse myoblasts were not statistically significant (F=2.61, 4.72, 3.52; with P values above 0.05). The water absorption of Ag/MSN group was significantly different from that of MSN group and Ag/MSN-Chi group (t=0.482, 1.159; with P values above 0.05). There was no significant difference in PT between Ag/MSN-Chi group, Ag/MSN group, MSN group and blank control group (F=10.28, P>0.05). The APTT of Ag/MSN-Chi group, Ag/MSN group, MSN group and blank control group were (20.9±2.1), (28.5±3.4), (31.4±2.6), (38.7±2.5) s, respectively, the difference of the 4 groups was statistically significant (F=8.70, P 0.05); after incubation for 0.5 h, the inhibition rates of Ag/MSN group and Ag/MSN-Chi group were (99.7±5.2)% and (97.1±5.4)%, respectively, compared with the incubation rate of 0.5 h in MSN group (11.2±5.8)%, the differences were statistically significant (t=19.678, 18.775; with P values below 0.05). After 24 h of culture, the inhibition rates of Ag/MSN group and Ag/MSN-Chi group were (73.2±5.1)% and (72.9±6.9)%, respectively, compared with MSN group (11.8±5.7)%, the differences were statistically significant significance (t=13.904, 11.825; with P values below 0.05). The hemostasis time of Ag/MSN-Chi group, Ag/MSN group and control group were (12.3±1.5), (17.2±3.4), (28.1±3.8) s, respectively, the difference between the three groups was statistically significant (F=5.892, P<0.05); the Ag/MSN-Chi group and the Ag/MSN group were significantly different from the control group (t=9.473, 5.236; with P values below 0.05); and the Ag/MSN-Chi group was compared with the Ag/MSN group, the difference was statistically significant (t=3.230, P<0.05). Conclusion Ag/MSN-Chi has better water absorption performance, hemostatic property and antibacterial property without increasing cytotoxicity. Key words: Chitosan; Silver; Hemostasis; Mesoporous silica nanoparticle; Antibacterial