Bio‐Inspired Synthesis of Hollow Mesoporous Bioactive Glass Nanoparticles Using Calcium Carbonate as Solid Template

Abstract

We report a surfactant free route to synthesize hollow mesoporous bioactive glass nanoparticles at ambient atmospheric condition. The synthesized particles contain hollow core as a result of mild acid mediated removal of calcium carbonate nanoparticles used as hard template. Removal of template was confirmed through FTIR and XRD while round morphology and sizes below 100 nm could be observed by TEM. In addition, N 2 adsorption and desorption analysis confirmed hollow and mesoporous nature of the bioactive glass shell. Interestingly, post removal of template, particles reported higher surface area, pore volume and pore diameter along with decrease in surface charge. Deposition of hydroxyapatite on hollow bioactive glass in Simulated Buffer Fluid (SBF) could be observed from Day 7 of immersion while well-developed hydroxyapatite depositions could be observed by Day 30. This proved bioactivity of the material while cytotoxicity analysis on Human Osteosarcoma cell line (U2OS) through MTT assay proved the biocompatible nature of the hollow bioactive glass particle.

One‐Pot Synthesis of Doxorubicin‐Bioactive Glass‐Ceramic Hybrid Nanoparticles through a Bio‐Inspired Route for Anti‐Cancer Therapy

“…Apart from this, elemental peaks of sodium, phosphorous and calcium can further be detected in all DOX‐BG ceramicnanoparticles indicating successful integration of the same in the Si−O network. However, when compared to previous studies, the amount of Ca was seen to be lower possibly due to removal of the salts during the washing steps [13,39,43] . Another reason can be due to compromised interactions of Ca 2+ ions with the non‐bonding O of the Si−O − groups present in the BG ceramic structure due to the interactions of the latter with DOX.…”

“…This can be due to the irregularities in the bioactive glass‐ceramic structure due to presence of non‐bonding oxygen and presence of PO 4 − , Ca 2+ , Na + ions in the silica ring structure acting asnetworkmodifiers. Such an observation has been earlier recorded for bioactive glass‐ceramic and other inorganic depositions in case of bio‐inspire routes of synthesis in presence of Tris(hydroxymethyl)aminomethane buffers [35,37,39,47,54,55] . In a study by Lin et al on sol‐gel synthesis of 70S30C bioactive glass‐ceramic particles, the presence of large number of nano‐pores on 70S30Cparticles could be detected through nitrogen adsorption‐desorption method and was attributed to be derived from interstitial spaces between secondary particles.…”

“…MTT provides an estimation of cellular viability through measuring mitochondrial activity which reduces the tetrazolium component of MTT into solid formazan crystals which remain deposited in the wells. The biocompatibility of native bioactive glass‐ceramic nanoparticles without anti‐cancer drugs have been proven in earlier studies [37,39] . Due to superior loading and release properties of 0.75 DOX‐BG ceramic nanoparticles when compared to 0.25 and 0.50 DOX‐BG ceramicnanoparticles, 0.75 DOX‐BG ceramic nanoparticles have been mainly reported for studying cytotoxicity activity (0.50 DOX‐BG ceramic is included in Figure S3a).…”

“…The doxorubicin−TRIZMA® solution was placed on a magnetic stirrer at 500 rpm at temperature of 37 °C.Various precursors of bioactive glass‐ceramic like Tetraethyl orthosilicate (TEOS), Triethyl Phosphate (TEP), Sodium Acetate (NaAc) and Calcium Acetate (CaAc) were added sequentially at an interval of 30 min. The concentration of all precursors has been optimized based on earlier studies carried out with other templates through this method [35–39] . It has been observed in traditional Stober's method that increasing concentration of precursor like TEOS or an increased reaction time lead to increase in size of the particle formed [40,41] .…”

“…The biocompatibility of native bioactive glass-ceramic nanoparticles without anti-cancer drugs have been proven in earlier studies. [37,39] Due to superior loading and release properties of 0.75 DOX-BG ceramic nanoparticles when compared to 0.25 and 0.50 DOX-BG ceramicnanoparticles, 0.75 DOX-BG ceramic nanoparticles have been mainly reported for studying cytotoxicity activity (0.50 DOX-BG ceramic is included in Figure S3a). With increasing concentration of 0.75 DOX-BG ceramic nanoparticles (10 μg/ml to 1 mg/ ml), cytotoxicity was observed to have increased in a dose dependent manner.…”