Montmorillonite, a natural biocompatible nanosheet with intrinsic antitumor activity

Exploring the Potential of Montmorillonite as an Antiproliferative Nanoagent against MDA-MB-231 and MCF-7 Human Breast Cancer Cells

Unlike MCF-7 cells, MDA-MB-231 cells are unresponsive to hormone therapy and often show resistance to chemotherapy and radiotherapy. Here, the antiproliferative effect of biocompatible montmorillonite (Mt) nanosheets on MDA-MB-231 and MCF-7 human breast cancer cells was evaluated by MTT assay, flow cytometry, and qRT-PCR. The results showed that the Mt IC50 for MDA-MB-231 and MCF-7 cells in a fetal bovine serum (FBS)-free medium was ~50 and ~200 µg/mL, and in 10% FBS medium ~400 and ~2000 µg/mL, respectively. Mt caused apoptosis in both cells by regulating related genes including Cas-3, P53, and P62 in MDA-MB-231 cells and Bcl-2, Cas-8, Cas-9, P53, and P62 in MCF-7 cells. Also, Mt arrested MCF-7 cells in the G0/G1 phase by altering Cyclin-D1 and P21 expression, and caused sub-G1 arrest and necrosis in both cells, possibly through damaging the mitochondria. However, fewer gene expression changes and more sub-G1 arrest and necrosis were observed in MDA-MB-231 cells, confirming the higher vulnerability of MDA-MB-231 cells to Mt. Furthermore, MDA-MB-231 cells appeared to be much more vulnerable to Mt compared to other cell types, including normal lung fibroblast (MRC-5), colon cancer (HT-29), and liver cancer (HepG2) cells. The higher vulnerability of MDA-MB-231 cells to Mt was inferred to be due to their higher proliferation rate. Notably, Mt cytotoxicity was highly dependent on both the Mt concentration and serum level, which favors Mt for the local treatment of MDA-MB-231 cells. Based on these results, Mt can be considered as an antiproliferative nanoagent against MDA-MB-231 cells and may be useful in the development of local nanoparticle-based therapies.

Layered Clay Minerals in Cancer Therapy: Recent Progress and Prospects

Cancer is one of the deadliest diseases, and current treatment regimens suffer from limited efficacy, nonspecific toxicity, and chemoresistance. With the advantages of good biocompatibility, large specific surface area, excellent cation exchange capacity, and easy availability, clay minerals have been receiving ever-increasing interests in cancer treatment. They can act as carriers to reduce the toxic side effects of chemotherapeutic drugs, and some of their own properties can kill cancer cells, etc. Compared with other morphologies clays, layered clay minerals (LCM) have attracted more and more attention due to adjustable interlayer spacing, easier ion exchange, and stronger adsorption capacity. In this review, the structure, classification, physicochemical properties, and functionalization methods of LCM are summarized. The state-of-the-art progress of LCM in antitumor therapy is systematically described, with emphasis on the application of montmorillonite, kaolinite, and vermiculite. Furthermore, the property-function relationships of LCM are comprehensively illustrated to reveal the design principles of clay-based antitumor systems. Finally, foreseeable challenges and outlook in this field are discussed.

XRD and cytotoxicity assay of submitted nanomaterial industrial samples in the Philippines

Distinct properties that nanomaterials possess compared to their bulk counterparts are attributed to their characteristic high surface area to volume ratios, and the prevalence of structure and shape effects at the nanoscale. However, these interesting properties are also accompanied by health hazards that are not seen in bulk materials. In the context of Philippine research and industry, the issue of nanosafety and the creation of nanotechnology guidelines have long been overlooked. This is of particular importance considering that nanotechnology research in the Philippines leans heavily towards medicinal and agricultural applications. In this study, nanomaterial samples from the industry submitted through the Philippine Industrial Technology Development Institute (ITDI) were analyzed using XRD and MTT cytotoxicity assay. XRD results show significant band broadening in the diffraction patterns of halloysite nanoclay, bentonite nanoparticles, silver nanoparticles, and CaCO3 nanoparticles, indicating that samples were in the nanometer range. The diffraction pattern of TiO2, however, did not exhibit band broadening, which may be due to the tendency of TiO2 nanoparticles to aggregate. Submitted samples were also assessed for their effect on cell viability using MTT cytotoxicity assay. Among these samples, only silver nanoparticles exhibited cytotoxicity to the AA8 cell line.

Calcium montmorillonite as potential carrier in release of bisphosphonates

There is a strong need to search for more effective bisphosphonates carriers which will lead to increased bioavailability of bone tissue engineering. Montmorillonite and calcium montmorillonite were used as risedronate...

Copper/Zinc-Modified Palygorskite Protects Against Salmonella Typhimurium Infection and Modulates the Intestinal Microbiota in Chickens

Palygorskite (Pal), a clay nanoparticle, has been demonstrated to be a vehicle for drug delivery. Copper has antibacterial properties, and zinc is an essential micronutrient for intestinal health in animals and humans. However, whether copper/zinc-modified Pal (Cu/Zn-Pal) can protect chickens from Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) infection remains unclear. In this study, three complexes (Cu/Zn-Pal-1, Cu/Zn-Pal-2, and Cu/Zn-Pal-3) were prepared, and Cu/Zn-Pal-1 was shown to be the most effective at inhibiting the growth of S. Typhimurium in vitro, whereas natural Pal alone had no inhibitory effect. In vivo, Cu/Zn-Pal-1 reduced S. Typhimurium colonization in the intestine of infected chickens and relieved S. Typhimurium-induced organ and intestinal mucosal barrier damage. Moreover, this reduction in Salmonella load attenuated intestinal inflammation and the oxidative stress response in challenged chickens. Additionally, Cu/Zn-Pal-1 modulated the intestinal microbiota in infected chickens, which was characterized by the reduced abundance of Firmicutes and the increased abundance of Proteobacteria and Bacteroidetes. Our results indicated that the Cu/Zn-Pal-1 complex may be an effective feed supplement for reducing S. Typhimurium colonization of the gut.

Montmorillonite nanosheets with enhanced photodynamic performance for synergistic bacterial ablation

Montmorillonite (MMT), as a naturally sourced and FDA-approved biomaterial, has attracted considerable attention due to its extensive application in biomedical areas, such as intestinal ailments, drug delivery, and additive manufacturing. In this work, two-dimensional montmorillonite (2D-MMT) ultrathin nanosheets were successfully prepared from sodium montmorillonite (Na-MMT) by utilizing a freeze-drying assisted method. Possessing a large specific surface area and increased number of exposed hydroxyl groups, 2D-MMT nanosheets exhibited better antibacterial ability than the original Na-MMT. More strikingly, we found that both 2D-MMT nanosheets and Na-MMT could generate reactive oxygen species (ROS) upon visible light illumination, which could promote their antibacterial efficiency. As a result, 2D-MMT nanosheets showed efficient antibacterial performance in the presence of light towards Escherichia coli with a simultaneous enhancement of surface adsorption and photodynamic ablation. What's more, a possible mechanism for ROS generation by MMT upon light illumination was first proposed in this work. The combination of the increased physical adsorption capacity and ROS generation ability of 2D-MMT nanosheets would help inspire the development of MMT as a promising antimicrobial candidate in the future.