522 results match your criteria: "200 College Street[Affiliation]"

Colloid-Forming Prodrug-Hydrogel Composite Prolongs Lower Intraocular Pressure in Rodent Eyes after Subconjunctival Injection.

Adv Mater

January 2025

Department of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada.

Colloidal drug aggregates (CDAs) are challenging in drug discovery due to their unpredictable formation and interference with screening assays. These limitations are turned into a strategic advantage by leveraging CDAs as a drug delivery platform. This study explores the deliberate formation and stabilization of CDAs for local ocular drug delivery, using a modified smallmolecule glaucoma drug.

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Ultrafine Particle Generation from Ozone Oxidation of Cannabis Smoke.

Environ Sci Technol

December 2024

Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.

Cannabis smoke is a complex aerosol mixture, featuring characteristic monoterpenes and sesquiterpenes which are susceptible to reaction with ozone and other oxidants. These reactions form less-volatile species which can contribute to secondary organic aerosol (SOA) and ultrafine particle (UFP) formation. In this work, the reaction of ozone with cannabis smoke was observed in an environmental chamber.

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Bottlebrush polymers are complex architectures with densely grafted polymer side chains along polymeric backbones. The dense and conformationally extended chains in bottlebrush polymers give rise to unique properties, including low chain entanglement, low critical aggregation concentrations, and elastomeric properties in the bulk phase. Conjugated polymers have garnered attention as lightweight, processible, and flexible semi-conducting materials.

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Enzymatic Routes to Designer Hemicelluloses for Use in Biobased Materials.

JACS Au

November 2024

Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada.

Various enzymes can be used to modify the structure of hemicelluloses directly in vivo or following extraction from biomass sources, such as wood and agricultural residues. Generally, these enzymes can contribute to designer hemicelluloses through four main strategies: (1) enzymatic hydrolysis such as selective removal of side groups by glycoside hydrolases (GH) and carbohydrate esterases (CE), (2) enzymatic cross-linking, for instance, the selective addition of side groups by glycosyltransferases (GT) with activated sugars, (3) enzymatic polymerization by glycosynthases (GS) with activated glycosyl donors or transglycosylation, and (4) enzymatic functionalization, particularly via oxidation by carbohydrate oxidoreductases and via amination by amine transaminases. Thus, this Perspective will first highlight enzymes that play a role in regulating the degree of polymerization and side group composition of hemicelluloses, and subsequently, it will explore enzymes that enhance cross-linking capabilities and incorporate novel chemical functionalities into saccharide structures.

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Molecular Structure of Omniphobic, Surface-Grafted Polydimethylsiloxane Chains.

Small

November 2024

Department of Mechanical & Industrial Engineering, University of Toronto, 5 King's College Rd, Toronto, Ontario, M5S 3G8, Canada.

The unique surface properties of grafted polydimethylsiloxane (PDMS) chains, particularly their omniphobicity and low friction, are influenced by molecular structure and tethering density. Despite molecularly smoothness and homogeneity, these surfaces exhibit significant variability in wettability and contact angle hysteresis (CAH). This work uncovers the molecular structure of grafted PDMS chains.

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Advancing aluminum-ion batteries: unraveling the charge storage mechanisms of cobalt sulfide cathodes.

Sci Rep

November 2024

Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, ON, M5S3E4, Canada.

Rechargeable aluminum-ion batteries (AIBs) stand out as a potential cornerstone for future battery technology, thanks to the widespread availability, affordability, and high charge capacity of aluminum. However, the efficacy of current AIBs on the market is significantly limited by the charge storage process within their graphite cathodes. To fully realize the capabilities of AIBs, the discovery of a new cathode material is essential.

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Pavement wear generates microplastics in stormwater runoff.

J Hazard Mater

January 2025

Department of Civil and Mineral Engineering, University of Toronto, 35 St. George Street, Toronto, ON M5S 1A4, Canada; Civil and Environmental Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada. Electronic address:

Tire and road wear particles are a major source of microplastics to urban stormwater. They are composed of hetero-aggregates of abraded tire and pavement particles that are difficult to distinguish. While tire wear is a known source of microplastics, little is known on the contribution of pavement wear.

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Breaking dielectric dilemma via polymer functionalized perovskite piezocomposite with large current density output.

Nat Commun

November 2024

Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave west, Waterloo, N2L 3G1, ON, Canada.

Organometal halide perovskite (OHP) composites are flexible and easy to synthesize, making them ideal for ambient mechanical energy harvesting. Yet, the output current density from the piezoelectric nanogenerators (PENGs) remains orders of magnitude lower than their ceramic counterparts. In prior composites, high permittivity nanoparticles enhance the dielectric constant (ϵ) but reduce the dielectric strength (E).

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Ion-Mediated Cross-Linking of Hyaluronic Acid into Hydrogels without Chemical Modification.

Biomacromolecules

December 2024

Department of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada.

Hyaluronic acid (HA) is a biomedically relevant polymer widely explored as a component of hydrogels. The prevailing approaches for cross-linking HA into hydrogels require chemically modifying the polymer, which can increase processing steps and complicate biocompatibility. Herein, we demonstrate an alternative approach to cross-link HA that eliminates the need for chemical modifications by leveraging the interactions between metal cations and the negatively charged, ionizable functional groups on HA.

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Gradient-Layered MXene/Hollow Lignin Nanospheres Architecture Design for Flexible and Stretchable Supercapacitors.

Nanomicro Lett

October 2024

Jiangsu Provincial Key Lab of Sustainable Pulp and Paper Technology and Biomass Materials, NanJing Forestry University, Nanjing, 210037, People's Republic of China.

With the rapid development of flexible wearable electronics, the demand for stretchable energy storage devices has surged. In this work, a novel gradient-layered architecture was design based on single-pore hollow lignin nanospheres (HLNPs)-intercalated two-dimensional transition metal carbide (TiCT MXene) for fabricating highly stretchable and durable supercapacitors. By depositing and inserting HLNPs in the MXene layers with a bottom-up decreasing gradient, a multilayered porous MXene structure with smooth ion channels was constructed by reducing the overstacking of MXene lamella.

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Reversibly Compressible Silanated Cellulose Nanofibril Aerogel for Triboelectric Taekwondo Scoring Sensors.

Small

December 2024

National Creative Research Initiative for Functionally Antagonistic Nano-Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Daejeon, Yuseong-gu, 34141, Republic of Korea.

The integration of bio-based materials into triboelectric nanogenerators (TENGs) for energy harvesting from human body motions has sparked considerable research attention. Here, a silanated cellulose nanofibril (SCNF) aerogel is reported for structurally reliable TENGs and reversely compressible Taekwondo scoring sensors under repeated impacts. The preparation of the aerogel involves silanizing cellulose nanofibers (CNFs) with vinyltrimethoxysilane (VTMS), following by freeze-drying and post-heating treatment.

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Lignin-containing cellulose nanocrystals enhanced electrospun polylactic acid-based nanofibrous mats: Strengthen and toughen.

Int J Biol Macromol

September 2024

Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China.

Biodegradable polylactic acid (PLA) nanofibrous mats prepared by electrospinning serve as suitable packaging materials. However, their practical applications are limited by their weak mechanical properties, poor thermal stability, and high cost. In this study, green and low-cost lignin-containing cellulose nanocrystals (LCNCs) with different lignin contents were developed and employed as reinforced materials to synergistically enhance the thermal, mechanical, and hydrophobic properties of PLA electrospun nanofibrous mats.

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Leveraging the Physicochemical Attributes of Biomimetic Hydrogel Nanocomposites in Stem Cell Differentiation.

Biomacromolecules

December 2024

Amity Institute of Click Chemistry Research and Studies, Amity University, Sector-125, Noida, Uttar Pradesh 201313, India.

The field of tissue engineering has witnessed significant advancements with the advent of hydrogel nanocomposites (HNC), emerging as a highly promising platform for regenerative medicine. HNCs provide a versatile platform that significantly enhances the differentiation of stem cells into specific cell lineages, making them highly suitable for tissue engineering applications. By incorporating nanoparticles, the mechanical properties of hydrogels, such as elasticity, porosity, and stiffness, are improved, addressing common challenges such as short-term stability, cytotoxicity, and scalability.

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Multicellular spheroids and patient-derived organoids find many applications in fundamental research, drug discovery, and regenerative medicine. Advances in the understanding and recapitulation of organ functionality and disease development require the generation of complex organoid models, including organoids with diverse morphologies. Microfluidics-based cell culture platforms enable time-efficient confined organoid generation.

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Redesigned chondroitinase ABC degrades inhibitory chondroitin sulfate proteoglycans in vitro and in vivo in the stroke-injured rat brain.

Biomaterials

March 2025

Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada; Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON, M5S 3E1, Canada; Institute of Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON, M5S 3G9, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada. Electronic address:

Injuries to the central nervous system, such as stroke and traumatic spinal cord injury, result in an aggregate scar that both limits tissue degeneration and inhibits tissue regeneration. The aggregate scar includes chondroitin sulfate proteoglycans (CSPGs), which impede cell migration and axonal outgrowth. Chondroitinase ABC (ChASE) is a potent yet fragile enzyme that degrades CSPGs, and thus may enable tissue regeneration.

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The influence of the axial group on the crystal structures of boron subphthalocyanines.

Acta Crystallogr C Struct Chem

October 2024

Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5, Canada.

The crystal structures of 16 boron subphthalocyanines (BsubPcs) with structurally diverse axial groups were analyzed and compared to elucidate the impact of the axial group on the intermolecular π-π interactions, axial-group interactions, axial bond length and BsubPc bowl depth. π-π interactions between the isoindole units of adjacent BsubPc molecules most often involve concave-concave packing, whereas axial-group interactions with adjacent BsubPc molecules tend to favour the convex side of the BsubPc bowl. Furthermore, axial groups that contain O and/or F atoms tend to have significant hydrogen-bonding interactions, while axial groups containing arene site(s) can participate in π-π interactions with the BsubPc bowl, both of which can strongly influence the crystal packing.

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Ionizable Drugs Enable Intracellular Delivery of Co-Formulated siRNA.

Adv Mater

October 2024

Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, M5S 3G9, Canada.

Targeting complementary pathways in diseases such as cancer can be achieved with co-delivery of small interfering ribonucleic acid (siRNA) and small molecule drugs; however, current formulation strategies are typically limited to one, but not both. Here, ionizable small molecule drugs and siRNA are co-formulated in drug-rich nanoparticles. Ionizable analogs of the selective estrogen receptor degrader fulvestrant self-assemble into colloidal drug aggregates and cause endosomal disruption, allowing co-delivery of siRNA against a non-druggable target.

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Mussel-Inspired Polymer Binders for Organic Electrodes.

Small

November 2024

Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.

The development of polymer binders is necessary to meet the growing demands of modern energy storage technologies. While catechol-containing materials are proven successful in silicon anodes, their application in organic batteries remains unexplored. In this contribution, the synthesis of four polymers are described with nearly identical side chain composition but varying backbone structures.

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Mechanical and Insulation Performance of Rigid Polyurethane Foam Reinforced with Lignin-Containing Nanocellulose Fibrils.

Polymers (Basel)

July 2024

Graduate Department of Forestry, University of Toronto, 33 Willcocks Street, Toronto, ON M5S 3B3, Canada.

Isocyanates are critical components that affect the crosslinking density and structure of polyurethane (PU) foams. However, due to the cost and hazardous nature of the precursor for isocyanate synthesis, there is growing interest in reducing their usage in polyurethane foam production-especially in rigid PU foams (RPUF) where isocyanate is used in excess of the stoichiometric ratio. In this study, lignin-containing nanocellulose fibrils (LCNF) were explored as mechanical reinforcements for RPUF with the goal of maintaining the mechanical performance of the foam while using less isocyanate.

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This paper presents an in-depth investigation into the optimization of rare earth element (REE) separation through electrodialysis, leveraging a newly developed Class II phenomenological model. This study explores the pivotal roles of the HEDTA/Nd molar ratio and pH of feed solution on enhancing the separation efficiency of neodymium (Nd) and praseodymium (Pr) from lanthanum (La) and cerium (Ce). By integrating expanded Nernst-Planck equations and the concept of limiting current density, the model offers a sophisticated understanding of ion transport dynamics and the impacts of concentration polarization.

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Quantifying remediation of chlorinated volatile compounds by sulfidated nano zerovalent iron treatment using numerical modeling and CSIA.

Water Res

October 2024

Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario, M5S 3B1, Canada; Institut de Physique du Globe de Paris (IPGP), Université Paris Cité, 1 Rue Jussieu, Paris 75005, France. Electronic address:

Sulfidated nanoscale zerovalent iron (S-nZVI) has demonstrated promising reactivity and longevity for remediating chlorinated volatile compounds (cVOC) contaminants in laboratory tests. However, its effectiveness in field applications remains inadequately evaluated. This study provides the first quantitative evaluation of the long-term effectiveness of carboxymethyl cellulose-stabilized S-nZVI (CMC-S-nZVI) at a cVOC-contaminated field site.

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Background: Day-to-day variation in the measurement of SARS-CoV-2 in wastewater can challenge public health interpretation. We assessed a Bayesian smoothing and forecasting method previously used for surveillance and short-term projection of COVID-19 cases, hospitalizations, and deaths.

Methods: SARS-CoV-2 viral measurement from the sewershed in Ottawa, Canada, sampled at the municipal wastewater treatment plant from July 1, 2020, to February 15, 2022, was used to assess and internally validate measurement averaging and prediction.

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Microfluidic extensional flow device to study mass transfer dynamics in the polymer microparticle formation process.

Soft Matter

August 2024

Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada.

Polymer microparticles are often used to encapsulate drugs for sustained drug-release treatments. One of the ways they are manufactured is by using a solvent extraction process, in which the polymer solution is emulsified into an aqueous bulk phase using a surfactant as a stabilizing agent, followed by the removal of the solvent. The radius of a polymer drop decreases as a function of time until the polymer reaches the gelling point, after which it is separated and dried.

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Impact of particle size and associated minerals on rare earth desorption and incorporation mechanisms in a South American ion-adsorption clay.

Sci Rep

July 2024

Laboratory for Strategic Materials, Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada.

This research delves into the intricate nexus of particle size, mineralogical composition, surface attributes, elemental mapping, and rare earth element (REE) adsorption mechanisms within an ion-adsorption clay sample from South America. The investigation entails the fractionation of the ion-adsorption clay into three size categories: S1 (< 0.25 mm), S2 (0.

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Article Synopsis
  • This study explores multi-element compound-specific isotope analysis (CSIA) to assess the biodegradation of 2,3-dichloroaniline (2,3-DCA), a significant industrial chemical, during controlled laboratory experiments.* -
  • Findings reveal negligible carbon and hydrogen isotope fractionation but notable inverse nitrogen isotope fractionation during the aerobic biodegradation, suggesting that the reaction’s initial enzymatic step might limit the process.* -
  • The research indicates that using nitrogen isotope signatures can help estimate biodegradation levels in contaminated sites, with potential rates reaching 80-90%, showcasing multi-element CSIA as a promising method for studying environmental chemical transformations.*
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