Mesoporous Silica and Organosilica Nanoparticles: Physical Chemistry, Biosafety, Delivery Strategies, and Biomedical Applications.

Predetermining the physico-chemical properties, biosafety, and stimuli-responsiveness of nanomaterials in biological environments is essential for safe and effective biomedical applications. At the forefront of biomedical research, mesoporous silica nanoparticles and mesoporous organosilica nanoparticles are increasingly investigated to predict their biological outcome by materials design. In this review, it is first chronicled that how the nanomaterial design of pure silica, partially hybridized organosilica, and fully hybridized organosilica (periodic mesoporous organosilicas) governs not only the physico-chemical properties but also the biosafety of the nanoparticles. The impact of the hybridization on the biocompatibility, protein corona, biodistribution, biodegradability, and clearance of the silica-based particles is described. Then, the influence of the surface engineering, the framework hybridization, as well as the morphology of the particles, on the ability to load and controllably deliver drugs under internal biological stimuli (e.g., pH, redox, enzymes) and external noninvasive stimuli (e.g., light, magnetic, ultrasound) are presented. To conclude, trends in the biomedical applications of silica and organosilica nanovectors are delineated, such as unconventional bioimaging techniques, large cargo delivery, combination therapy, gaseous molecule delivery, antimicrobial protection, and Alzheimer's disease therapy.

Hybrid Iron Oxide-Graphene Oxide-Polysaccharides Microcapsule: A Micro-Matryoshka for On-Demand Drug Release and Antitumor Therapy In Vivo.

Premature drug release is a common drawback in stimuli-responsive drug delivery systems (DDS), especially if it depends on internal triggers, which are hard to control, or a single external stimulus, which can only have one function. Thus, many DDS systems have been reported that combined different triggers; however, limited success has been established in fine-tuning the release process, mainly due to the poor bioavailability and complexity of the reported designs. This paper reports the design of a hybrid microcapsule (h-MC) by a simple layer-by-layer technique comprising polysaccharides (sodium alginate, chitosan, and hyaluronic acid), iron oxide, and graphene oxide (GO). Electrostatic assembly of the oppositely charged polysaccharides and graphene sheets provided a robust structure in which to load drugs through pH control. The polysaccharide component ensured high biocompatibility, bioavailability, and tumor cells targeting. The alternative magnetic field and near-infrared laser triggerable Fe3O4@GO component provided for dual high-energy and high-penetration hyperthermia therapy. On-demand drug release from h-MC can be achieved by synchronizing these external triggers, making the release highly controllable. The synergistic effect of hyperthermia and chemotherapy was successfully confirmed in vitro and in vivo.

Colorimetric peroxidase mimetic assay for uranyl detection in sea water.

Uranyl (UO2(2+)) is a form of uranium in aqueous solution that represents the greatest risk to human health because of its bioavailability. Different sensing techniques have been used with very sensitive detection limits especially the recently reported uranyl-specific DNAzymes systems. However, to the best of our knowledge, few efficient detection methods have been reported for uranyl sensing in seawater. Herein, gold nanoclusters (AuNCs) are employed in an efficient spectroscopic method to detect uranyl ion (UO2(2+)) with a detection limit of 1.86 µM. In the absence of UO2(2+), the BSA-stabilized AuNCs (BSA-AuNCs) showed an intrinsic peroxidase-like activity. In the presence of UO2(2+), this activity can be efficiently restrained. The preliminary quenching mechanism and selectivity of UO2(2+) was also investigated and compared with other ions. This design strategy could be useful in understanding the binding affinity of protein-stabilized AuNCs to UO2(2+) and consequently prompt the recycling of UO2(2+) from seawater.