Contrast agents (CAs) play an important role in enhancing the magnetic resonance imaging (MRI) performance for accurate tumor diagnosis, which, however, may give rise to unexceptional issues such as in vivo accumulation and bio-toxicity. Here we report on manganese silicate nanoparticles (denoted as MnSNs) as highly biocompatible and pH/GSH-responsive T1-weighted MRI CAs. The MnSNs were synthesized via a facile, cost-effective and environmentally friendly route based on one-step rapid precipitation between the Mn2+ cation and the SiO32− anion in aqueous solution at room temperature without any other additives, and showed excellent dispersion stability in water or PBS for weeks without any surface modification at ambient temperature. The MnSNs present an efficient pH/GSH-responsive T1-MRI feature based on the rapid changes in the relaxation rate in a mildly acidic/reducing environment both in vitro and in vivo, and furthermore, MnSNs showed negligible cellular cytotoxicity in vitro, no distinct tissue toxicity in vivo and fast clearance from the body organs and tissues in 24–72 h. Thus, the MnSNs are able to serve as a novel class of highly promising T1-MRI CAs for clinical cancer diagnosis.

•Magnetic core–shell mesoporous silica spheres with NiO nanoparticles were prepared.•A facile surfactant-free approach was developed.•The material possesses enough binding sites to bind His-tagged proteins.•The material possesses high magnetization for recycling separation of protein.We propose a facile strategy to prepare novel NiO nanoparticle-decorated magnetic core-mesoporous shell structured sub-microspheres (MMMs-NiO) through a facile surfactant-free “in situ silicate growth and NiO formation” approach. The successful deposition of NiO nanoparticles on magnetic cores was verified by XRD, EDS, TEM, SEM and BET characterizations. The NiO units on the obtained nanocomposites were used to selectively enrich and efficiently separate the His-tagged proteins via the specific coordination of histidine of proteins to Ni2+ ions. The magnetic core endows the sub-microparticle with high magnetism, enabling facile particle magnetic-separation from the solution under an external magnetic field. The obtained nanocomposites exhibit excellent water dispersity with well-defined size distribution (around 160 nm), mesoporous characteristics, and high magnetization (52.3 emu g−1). The nanocomposites exhibit excellent selective affinity to His-tag (93%), efficient dissociability by imidazole (86%), and convenient magnetic separability in the separation of His-tagged proteins, as well as from E. coli lysate, even to 5 separation cycles. Therefore, MMMs-NiO is expected to be a satisfactory candidate for practical application in facile and efficient bioseparation in the future. In addition, we expect the synthetic strategy could be extended for the surfactant-free synthesis of other kinds of mesoporous nano/micro-particles.

A novel type of fluorescent mesoporous silica nanoparticle (FMSN) has been successfully synthesised by hybridising mesoporous silica nanospheres with an aggregation-induced emission luminogen, a quinoline-malononitrile derivative. The FMSNs with uniform morphology show excellent AIE-active luminescence and good biocompatibility. Transmission electron microscopy (TEM) demonstrates that the well-ordered mesoporous structure in FMSNs is beneficial for drug delivery. When loaded with doxorubicin (DOX), DOX@FMSNs demonstrate pH-dependent release character and high cytotoxicity towards MCF-7 cancer cells. These FMSNs are expected to be promising multifunctional candidates as both bioimaging agents and drug carriers in cancer therapy.

A novel glucose-responsive controlled release of insulin system is constructed through coating enzyme multilayers on mesoporous silica particles (MSPs). The MSPs serve as the drug reservoir, and the enzyme multilayers cross-linked with glutaraldehyde act as a valve to control the release of insulin in response to the external glucose level.

Contrast agents (CAs) play an important role in enhancing the magnetic resonance imaging (MRI) performance for accurate tumor diagnosis, which, however, may give rise to unexceptional issues such as in vivo accumulation and bio-toxicity. Here we report on manganese silicate nanoparticles (denoted as MnSNs) as highly biocompatible and pH/GSH-responsive T1-weighted MRI CAs. The MnSNs were synthesized via a facile, cost-effective and environmentally friendly route based on one-step rapid precipitation between the Mn2+ cation and the SiO32− anion in aqueous solution at room temperature without any other additives, and showed excellent dispersion stability in water or PBS for weeks without any surface modification at ambient temperature. The MnSNs present an efficient pH/GSH-responsive T1-MRI feature based on the rapid changes in the relaxation rate in a mildly acidic/reducing environment both in vitro and in vivo, and furthermore, MnSNs showed negligible cellular cytotoxicity in vitro, no distinct tissue toxicity in vivo and fast clearance from the body organs and tissues in 24–72 h. Thus, the MnSNs are able to serve as a novel class of highly promising T1-MRI CAs for clinical cancer diagnosis.

A novel glucose-responsive controlled release of insulin system is constructed through coating enzyme multilayers on mesoporous silica particles (MSPs). The MSPs serve as the drug reservoir, and the enzyme multilayers cross-linked with glutaraldehyde act as a valve to control the release of insulin in response to the external glucose level.