The Correlation of Pore Size and Bioactivity of Spray-Pyrolyzed Mesoporous Bioactive Glasses

Abstract

SiO2–CaO–P2O5-based mesoporous bioactive glasses (MBGs) were synthesized by spray pyrolysis in this study. Three commonly used non-ionic tri-block copolymers (L121, P123, and F127) with various lengths of hydrophilic chains were applied as structural templates to achieve different pore sizes. A mesoporous structure was observed in each as-prepared specimen, and the results showed that the L121-treated MBG had the largest pore size. The results of bioactivity tests indicated that the growth of hydroxyapatite is related to the pore size of the materials.

Preparation and in Vitro Bioactivity of Micron-sized Bioactive Glass Particles Using Spray Drying Method

“…In addition, the average particle sizes of BG powders are computed as 8.8 ± 3.5, 6.4 ± 4.2 and 5.9 ± 3.5 µm for 58S, 68S and 76S BG powders, respectively. Meanwhile, it also shows that the particle size of spray dried BG powders is about 10 times bigger than the particles size of spray pyrolyzed BG powders (300-800 nm) [17][18][19]. However, owing to the distribution of droplet sizes, the average particle sizes still present standard deviations around 50% similar to the BG particles synthesized using spray pyrolysis [32].…”

“…However, owing to the nature of the ultrasonic atomizer, particle sizes of spray pyrolyzed BG lay around the sub-micron (300-800 nm) range [17][18][19]. This limits its applications, such as dermal fillings [20] and radioisotope vectors [10,11], which require a particle size up to few microns.…”

Mesoporous Properties of Bioactive Glass Synthesized by Spray Pyrolysis with Various Polyethylene Glycol and Acid Additions

“…In order to expand the clinical application of BG, it will be beneficial to increase the reaction areas by creating porous structures so that osteoconduction and osteoinduction can be promoted for bone regeneration. Scholars introduced the idea of adding polymer surfactant, such as P-123 (EO 20 PO 70 EO 20 ) or F-127(EO 106 PO 70 EO 106 ), as a structural template to fabricate mesoporous bioactive glass (MBG) to increase the specific surface area of BG effectively [ 18 , 19 , 20 ]. MBG possessing hollow, porous structure, and high specific surface area not only exhibits excellent bioactivities but also serves as drugs or bioactive molecular carriers [ 11 , 21 , 22 ].…”

“…MBG possessing hollow, porous structure, and high specific surface area not only exhibits excellent bioactivities but also serves as drugs or bioactive molecular carriers [ 11 , 21 , 22 ]. Nevertheless, both P-123 and F-127 have non-single composition and are copolymers of PPO-PEO [PEO, poly(ethylene oxide); PPO, poly(propylene oxide)] contains lipophilic and hydrophilic polymers, thus, it is difficult conducting a subtle examination of the surfactants’ physical properties [ 19 , 20 ]. Reports indicate that polyethylene glycol (PEG), a linear hydrophilic polymer, has been successfully applied as a surfactant for synthesizing MBG [ 23 , 24 ].…”

Effect of Acetic Acid Concentration on Pore Structure for Mesoporous Bioactive Glass during Spray Pyrolysis

“…However, the whole process takes a few days and it is a batch production. In contrast, the spray pyrolysis (SP) process offers the benefits of low cost, short process time, and continuous fabrication, which is suitable for mass production [ 9 , 10 ]. In addition, to fabricate mesoporous bioactive glass (MBG), surfactants such as F127 (EO 100 PO 65 EO 100 ) [ 11 ] and P123 (EO 20 PO 70 EO 20 ) [ 12 ] were commonly used as pore-forming agents, where EO is poly ethylene oxide and PO is poly propylene oxide.…”