Bradley Duncan

Bio: Bradley Duncan is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Colloidal gold & Nanoparticle. The author has an hindex of 22, co-authored 47 publications receiving 1923 citations. Previous affiliations of Bradley Duncan include University of Massachusetts Amherst & University of Massachusetts Boston.

Supramolecular regulation of bioorthogonal catalysis in cells using nanoparticle-embedded transition metal catalysts

Abstract: Regulation of bioorthogonal catalysis in living systems is challenging because of the complex intracellular environment. Now, the activity of protein-sized bioorthogonal nanozymes has been regulated by binding a supramolecular cucurbit[7]uril ‘gate-keeper’ onto the monolayer surface. This arrangement enables the controlled activation of profluorophores and prodrugs inside living cells for imaging and therapeutic applications.

The Interplay of Size and Surface Functionality on the Cellular Uptake of Sub-10 nm Gold Nanoparticles

Abstract: Correlation of the surface physicochemical properties of nanoparticles with their interactions with biosystems provides key foundational data for nanomedicine. We report here the systematic synthesis of 2, 4, and 6 nm core gold nanoparticles (AuNP) featuring neutral (zwitterionic), anionic, and cationic headgroups. The cellular internalization of these AuNPs was quantified, providing a parametric evaluation of charge and size effects. Contrasting behavior was observed with these systems: with zwitterionic and anionic particles, uptake decreased with increasing AuNP size, whereas with cationic particles, uptake increased with increasing particle size. Through mechanistic studies of the uptake process, we can attribute these opposing trends to a surface-dictated shift in uptake pathways. Zwitterionic NPs are primarily internalized through passive diffusion, while the internalization of cationic and anionic NPs is dominated by multiple endocytic pathways. Our study demonstrates that size and surface charge i...

Nanoparticle-Stabilized Capsules for the Treatment of Bacterial Biofilms.

Abstract: Bacterial biofilms are widely associated with persistent infections. High resistance to conventional antibiotics and prevalent virulence makes eliminating these bacterial communities challenging therapeutic targets. We describe here the fabrication of a nanoparticle-stabilized capsule with a multicomponent core for the treatment of biofilms. The peppermint oil and cinnamaldehyde combination that comprises the core of the capsules act as potent antimicrobial agents. An in situ reaction at the oil/water interface between the nanoparticles and cinnamaldehyde structurally augments the capsules to efficiently deliver the essential oil payloads, effectively eradicating biofilms of clinically isolated pathogenic bacteria strains. In contrast to their antimicrobial action, the capsules selectively promoted fibroblast proliferation in a mixed bacteria/mammalian cell system making them promising for wound healing applications.

Engineering precision nanoparticles for drug delivery

Abstract: In recent years, the development of nanoparticles has expanded into a broad range of clinical applications. Nanoparticles have been developed to overcome the limitations of free therapeutics and navigate biological barriers - systemic, microenvironmental and cellular - that are heterogeneous across patient populations and diseases. Overcoming this patient heterogeneity has also been accomplished through precision therapeutics, in which personalized interventions have enhanced therapeutic efficacy. However, nanoparticle development continues to focus on optimizing delivery platforms with a one-size-fits-all solution. As lipid-based, polymeric and inorganic nanoparticles are engineered in increasingly specified ways, they can begin to be optimized for drug delivery in a more personalized manner, entering the era of precision medicine. In this Review, we discuss advanced nanoparticle designs utilized in both non-personalized and precision applications that could be applied to improve precision therapies. We focus on advances in nanoparticle design that overcome heterogeneous barriers to delivery, arguing that intelligent nanoparticle design can improve efficacy in general delivery applications while enabling tailored designs for precision applications, thereby ultimately improving patient outcome overall.

Gold nanoparticles in biomedical applications: recent advances and perspectives

Abstract: Gold nanoparticles (GNPs) with controlled geometrical, optical, and surface chemical properties are the subject of intensive studies and applications in biology and medicine. To date, the ever increasing diversity of published examples has included genomics and biosensorics, immunoassays and clinical chemistry, photothermolysis of cancer cells and tumors, targeted delivery of drugs and antigens, and optical bioimaging of cells and tissues with state-of-the-art nanophotonic detection systems. This critical review is focused on the application of GNP conjugates to biomedical diagnostics and analytics, photothermal and photodynamic therapies, and delivery of target molecules. Distinct from other published reviews, we present a summary of the immunological properties of GNPs. For each of the above topics, the basic principles, recent advances, and current challenges are discussed (508 references).

Nanozymes: Classification, Catalytic Mechanisms, Activity Regulation, and Applications

Abstract: Because of the high catalytic activities and substrate specificity, natural enzymes have been widely used in industrial, medical, and biological fields, etc. Although promising, they often suffer from intrinsic shortcomings such as high cost, low operational stability, and difficulties of recycling. To overcome these shortcomings, researchers have been devoted to the exploration of artificial enzyme mimics for a long time. Since the discovery of ferromagnetic nanoparticles with intrinsic horseradish peroxidase-like activity in 2007, a large amount of studies on nanozymes have been constantly emerging in the next decade. Nanozymes are one kind of nanomaterials with enzymatic catalytic properties. Compared with natural enzymes, nanozymes have the advantages such as low cost, high stability and durability, which have been widely used in industrial, medical, and biological fields. A thorough understanding of the possible catalytic mechanisms will contribute to the development of novel and high-efficient nanozymes, and the rational regulations of the activities of nanozymes are of great significance. In this review, we systematically introduce the classification, catalytic mechanism, activity regulation as well as recent research progress of nanozymes in the field of biosensing, environmental protection, and disease treatments, etc. in the past years. We also propose the current challenges of nanozymes as well as their future research focus. We anticipate this review may be of significance for the field to understand the properties of nanozymes and the development of novel nanomaterials with enzyme mimicking activities.

Global life cycle releases of engineered nanomaterials

Abstract: Engineered nanomaterials (ENMs) are now becoming a significant fraction of the material flows in the global economy. We are already reaping the benefits of improved energy efficiency, material use reduction, and better performance in many existing and new applications that have been enabled by these technological advances. As ENMs pervade the global economy, however, it becomes important to understand their environmental implications. As a first step, we combined ENM market information and material flow modeling to produce the first global assessment of the likely ENM emissions to the environment and landfills. The top ten most produced ENMs by mass were analyzed in a dozen major applications. Emissions during the manufacturing, use, and disposal stages were estimated, including intermediate steps through wastewater treatment plants and waste incineration plants. In 2010, silica, titania, alumina, and iron and zinc oxides dominate the ENM market in terms of mass flow through the global economy, used mostly in coatings/paints/pigments, electronics and optics, cosmetics, energy and environmental applications, and as catalysts. We estimate that 63–91 % of over 260,000–309,000 metric tons of global ENM production in 2010 ended up in landfills, with the balance released into soils (8–28 %), water bodies (0.4–7 %), and atmosphere (0.1–1.5 %). While there are considerable uncertainties in the estimates, the framework for estimating emissions can be easily improved as better data become available. The material flow estimates can be used to quantify emissions at the local level, as inputs for fate and transport models to estimate concentrations in different environmental compartments.