Zongxi Li

Bio: Zongxi Li is an academic researcher from Harvard University. The author has contributed to research in topics: Mesoporous silica & Drug delivery. The author has an hindex of 16, co-authored 25 publications receiving 5042 citations. Previous affiliations of Zongxi Li include University of California, Los Angeles & University of California.

Mesoporous silica nanoparticles in biomedical applications

Abstract: This tutorial review provides an outlook on nanomaterials that are currently being used for theranostic purposes, with a special focus on mesoporous silica nanoparticle (MSNP) based materials. MSNPs with large surface area and pore volume can serve as efficient carriers for various therapeutic agents. The functionalization of MSNPs with molecular, supramolecular or polymer moieties, provides the material with great versatility while performing drug delivery tasks, which makes the delivery process highly controllable. This emerging area at the interface of chemistry and the life sciences offers a broad palette of opportunities for researchers with interests ranging from sol–gel science, the fabrication of nanomaterials, supramolecular chemistry, controllable drug delivery and targeted theranostics in biology and medicine.

Biocompatibility, Biodistribution, and Drug-Delivery Efficiency of Mesoporous Silica Nanoparticles for Cancer Therapy in Animals

Abstract: Mesoporous silica nanoparticles (MSNs) are a promising material for drug delivery. In this Full Paper, MSNs are first shown to be well tolerated, as demonstrated by serological, hematological, and histopathological examinations of blood samples and mouse tissues after MSN injection. Biodistribution studies using human cancer xenografts are carried out with in vivo imaging and fluorescent microscopy imaging, as well as with inductively coupled plasma mass spectroscopy. The results show that MSNs preferentially accumulate in tumors. Finally, the drug-delivery capability of MSNs is demonstrated by following tumor growth in mice treated with camptothecin-loaded MSNs. These results indicate that MSNs are biocompatible, preferentially accumulate in tumors, and effectively deliver drugs to the tumors and suppress tumor growth.

Engineered Design of Mesoporous Silica Nanoparticles to Deliver Doxorubicin and P-Glycoprotein siRNA to Overcome Drug Resistance in a Cancer Cell Line

Abstract: Overexpression of drug efflux transporters such as P-glycoprotein (Pgp) protein is one of the major mechanisms for multiple drug resistance (MDR) in cancer cells. A new approach to overcome MDR is to use a co-delivery strategy that utilizes a siRNA to silence the expression of efflux transporter together with an appropriate anticancer drug for drug resistant cells. In this paper, we report that mesoporous silica nanoparticles (MSNP) can be functionalized to effectively deliver a chemotherapeutic agent doxorubicin (Dox) as well as Pgp siRNA to a drug-resistant cancer cell line (KB-V1 cells) to accomplish cell killing in an additive or synergistic fashion. The functionalization of the particle surface with a phosphonate group allows electrostatic binding of Dox to the porous interior, from where the drug could be released by acidification of the medium under abiotic and biotic conditions. In addition, phosphonate modification also allows exterior coating with the cationic polymer, polyethylenimine, which en...

Aspect ratio determines the quantity of mesoporous silica nanoparticle uptake by a small GTPase-dependent macropinocytosis mechanism.

Abstract: Although the aspect ratio (AR) of engineered nanomaterials (ENMs) is one of the key physicochemical parameters that could determine biological outcome, not much is understood about how AR contributes to shaping biological outcome. By using a mesoporous silica nanoparticle (MSNP) library that has been constructed to cover a range of different lengths, we could demonstrate that the AR of rod-shaped particles determines the rate and abundance of MSNP uptake by a macropinocytosis process in HeLa and A549 cancer cell lines. MSNPs with an AR of 2.1-2.5 were taken up in larger quantities compared to shorter or longer length rods by a process that is sensitive to amiloride, cytochalasin D, azide, and 4 °C inhibition. The rods with intermediary AR also induced the maximal number of filopodia, actin polymerization, and activation of small GTP-binding proteins (e.g., Rac1, CDC42) that involve assembly of the actin cytoskeleton and filopodia formation. When assessing the role of AR in the delivery of paclitaxel or camptothecin, the rods with AR 2.1-2.5 were clearly more efficient for drug delivery and generation of cytotoxic killing in HeLa cells. All considered, our data suggest an active sensoring mechanism by which HeLa and A549 cells are capable of detecting AR differences in MSNP to the extent that accelerated macropinocytosis can be used to achieve more efficient drug delivery.

pH-operated nanopistons on the surfaces of mesoporous silica nanoparticles.

Abstract: The development of drug delivery systems for the targeted and on-demand release of pharmaceutical products has risen rapidly to become a contemporary challenge in the field of nanobiotechnology. Biocompatible mechanized phosphonate-clothed silica nanoparticles have been designed and fabricated in which the supramolecular machinery, which covers the surfaces of the nanoparticles, behaves like nanopistons, releasing encapsulated guest molecules in a controlled fashion under acidic conditions. The mechanized nanoparticles consist of a monolayer of β-cyclodextrin (β-CD) rings positioned selectively around the orifices of the nanopores of the mesoporous nanoparticles. A rhodamine B/benzidine conjugate was prepared for use as the nanopistons for movement in and out of the cylindrical cavities provided by the β-CD rings on the surfaces of the nanoparticles. Luminescence experiments indicated that the mechanized nanoparticles were able to store small cargo molecules (e.g., 2,6-naphthalenedisulfonic acid disodium) within their nanopores at neutral pH and then release them by passage through the cavities of the β-CD rings as soon as the pH was lowered to ∼5. In further investigations, the phosphonate-covered silica nanoparticles were functionalized selectively with the β-CD rings, but on this occasion, the seven linkers attaching the rings to the orifices surrounding the nanopores contained cleavable imine double bonds. The β-CD rings on the surface of the nanoparticles served as gates for the storage of large cargo molecules (e.g., rhodamine B) inside the nanopores of the nanoparticles under neutral conditions. Since imine bonds can be hydrolyzed under acidic conditions, the β-CD rings could be severed from the surface of the nanoparticles when the pH was decreased to 6, releasing the large cargo molecules. The results described here present a significant step toward the development of pH-responsive nanoparticle-based dual drug delivery vehicles that are potentially capable of being interfaced with biological systems.

Metal-organic frameworks in biomedicine.

Abstract: Metal Organic Frameworks in Biomedicine Patricia Horcajada,* Ruxandra Gref, Tarek Baati, Phoebe K. Allan, Guillaume Maurin, Patrick Couvreur, G erard F erey, Russell E. Morris, and Christian Serre* Institut Lavoisier, UMR CNRS 8180, Universit e de Versailles St-Quentin en Yvelines, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France Facult e de Pharmacie, UMR CNRS 8612, Universit e Paris-Sud, 92296 Châtenay-Malabry Cedex, France Institut Charles Gerhardt Montpellier, UMR CNRS 5253, Universit e Montpellier 2, 34095 Montpellier cedex 05, France EaStChem School of Chemistry, University of St. Andrews Purdie Building, St Andrews, KY16 9ST U.K.

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

Abstract: We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.

Mesoporous Silica Nanoparticles: Synthesis, Biocompatibility and Drug Delivery

Abstract: In the past decade, mesoporous silica nanoparticles (MSNs) have attracted more and more attention for their potential biomedical applications. With their tailored mesoporous structure and high surface area, MSNs as drug delivery systems (DDSs) show significant advantages over traditional drug nanocarriers. In this review, we overview the recent progress in the synthesis of MSNs for drug delivery applications. First, we provide an overview of synthesis strategies for fabricating ordered MSNs and hollow/rattle-type MSNs. Then, the in vitro and in vivo biocompatibility and biotranslocation of MSNs are discussed in relation to their chemophysical properties including particle size, surface properties, shape, and structure. The review also highlights the significant achievements in drug delivery using mesoporous silica nanoparticles and their multifunctional counterparts as drug carriers. In particular, the biological barriers for nano-based targeted cancer therapy and MSN-based targeting strategies are discussed. We conclude with our personal perspectives on the directions in which future work in this field might be focused.

Mesoporous silica nanoparticles in biomedical applications

Abstract: This tutorial review provides an outlook on nanomaterials that are currently being used for theranostic purposes, with a special focus on mesoporous silica nanoparticle (MSNP) based materials. MSNPs with large surface area and pore volume can serve as efficient carriers for various therapeutic agents. The functionalization of MSNPs with molecular, supramolecular or polymer moieties, provides the material with great versatility while performing drug delivery tasks, which makes the delivery process highly controllable. This emerging area at the interface of chemistry and the life sciences offers a broad palette of opportunities for researchers with interests ranging from sol–gel science, the fabrication of nanomaterials, supramolecular chemistry, controllable drug delivery and targeted theranostics in biology and medicine.

Cellular uptake of nanoparticles: journey inside the cell.

Abstract: Nanoscale materials are increasingly found in consumer goods, electronics, and pharmaceuticals. While these particles interact with the body in myriad ways, their beneficial and/or deleterious effects ultimately arise from interactions at the cellular and subcellular level. Nanoparticles (NPs) can modulate cell fate, induce or prevent mutations, initiate cell–cell communication, and modulate cell structure in a manner dictated largely by phenomena at the nano–bio interface. Recent advances in chemical synthesis have yielded new nanoscale materials with precisely defined biochemical features, and emerging analytical techniques have shed light on nuanced and context-dependent nano-bio interactions within cells. In this review, we provide an objective and comprehensive account of our current understanding of the cellular uptake of NPs and the underlying parameters controlling the nano-cellular interactions, along with the available analytical techniques to follow and track these processes.