Absolute ethyl alcohol

Mucin (from porcine stomach, Type III), 11-mercapto-1-undecanol, epichlorohydrin, diethylene glycol dimethyl ether, potassium chloride, potassium hexacyanoferrate (II) trihydrate, potassium ferricyanide (III), sodium phosphate, and d-mannose were purchased from Sigma-Aldrich (St. Louis, MO, USA). Absolute ethyl alcohol, sodium hydroxide, acetone, sulfuric acid, sodium acetate, acetic acid, and hydrogen peroxide were from DaeJung Chemicals & Metals Co., Ltd. (Gyeonggi-do, Korea). Carboxyfluorescein diacetate (CFDA) was obtained from Dojindo Molecular Technologies, Inc. (Rockville, MD, USA), and potassium phosphate from Pure Chemicals Co., Ltd. (Kyoto, Japan). Lysogeny broth (LB) broth and agar powder were purchased from BD (BD Difco, Lawrence, KS, USA).

For the synthesis of porous silica, sodium silicate solution (28–30 wt%, DAEJUNG, Gyeonggi-do, Korea) and cetyltrimethylammonium chloride (CTACl, 25 wt%, Sigma-Aldrich-Korea, Seoul, Korea) were used as a silica precursor and a surfactant, respectively. Hydrochloric acid (HCl, 35–37%, Samchun, Gyeonggi-do, Korea) was utilized as a pH control. Absolute ethyl alcohol (99.9%, DAEJUNG, Gyeonggi-do, Korea) was employed as a solvent during the surfactant removal process in which the synthesized silica was washed at room temperature several times. Finally, amine functional groups were introduced into the synthesized mesoporous silica using tetraethylene pentamine (TEPA, 93%, Kanto Chemical, Tokyo, Japan).

For the synthesis of hollow mesoporous silica, TEOS (tetraethyl orthosilicate, 98 wt%, Sigma-Aldrich-Korea, Seoul, Republic of Korea) and sodium silicate solution (28–30 wt%, DAEJUNG, Siheung-si, Republic of Korea) were used as silica precursors. To implement a hollow and internal pore structure, cetyltrimethylammonium chloride (CTACl, 25 wt%, Sigma-Aldrich-Korea, Seoul, Republic of Korea) was used as a surfactant. Hydrochloric acid (HCl, 35–37%, Samcheon, Seoul, Republic of Korea) and aqueous ammonia (NH4OH, 25~30%, Duksan, Seoul, Republic of Korea) were employed for pH control. Absolute ethyl alcohol (99.9%, DAEJUNG, Siheung-si, Republic of Korea) was utilized to remove the surfactant. Tetraethylene pentamine (TEPA, 93%, Kanto Chemical, Tokyo, Japan) was used for adding amine functional groups to the synthesized silica nanomaterials.