BioNano engineered hybrids for hypochlorous acid generation

Carbon nanotubes physicochemical properties influence the overall cellular behavior and fate

The unique properties of single walled carbon nanotubes (SWCNTs) make them viable candidates for versatile implementation in the next generation of biomedical devices for targeted delivery of chemotherapeutic agents or cellular-sensing probes. Such implementation requires user-tailored changes in SWCNT's physicochemical characteristics to allow for efficient cellular integration while maintaining nanotubes' functionality. However, isolated reports showed that user-tailoring could induce deleterious effects in exposed cells, from decrease in cellular proliferation, to changes in cellular adhesion, generation of reactive oxygen species or phenotypical variations, just to name a few. Before full implementation of SWCNTs is achieved, their toxicological profiles need to be mechanistically correlated with their physicochemical properties to determine how the induced cellular fate is related to the exposure conditions or samples' characteristics. Our study provides a comprehensive analysis of the synergistic cyto- and genotoxic effects resulted from short-term exposure of human lung epithelial cells to pristine (as manufactured) and user-tailored SWCNTs, as a function of their physicochemical properties. Specifically, through a systematic approach we are correlating the nanotube uptake and nanotube-induced cellular changes to the sample's physicochemical characteristics (e.g., metal impurities, length, agglomerate size, surface area, dispersion, and surface functionalization). By identifying changes in active hallmarks involved in cell-cell connections and maintaining epithelial layer integrity, we also determine the role that short-term exposure to SWCNTs plays in the overall cellular fate and cellular transformation. Lastly, we assess cellular structure-function relationships to identify non-apoptotic pathways induced by SWCNTs exposure that could however lead to changes in cellular behavior and cellular transformation. Our results show that the degree of cell transformation is a function of the physicochemical properties of the SWCNT, with the nanotube with higher length, higher metal content and larger agglomerate size reducing cell viability to a larger extent. Such changes in cell viability are also complemented by changes in cell structure, cycle and cell-cell interactions, all responsible for maintaining cell fate.

Facile fabrication of a recyclable nanobiocatalyst: immobilization of Burkholderia cepacia lipase on carbon nanofibers for the kinetic resolution of a racemic atenolol intermediate

Immobilization of surfactant treated Burkholderia cepacia lipase on the surface of carbon nanofibers was performed via two different methods: adsorption and covalent attachment.

Improved power density of an enzymatic biofuel cell with fibrous supports of high curvature

We developed and characterized two separate enzymatic biofuel cell systems attributing improved performance to electrode support morphological characteristics.

Carbon Nanotube Uptake Changes the Biomechanical Properties of Human Lung Epithelial Cells in a Time-dependent Manner

The toxicity of engineered nanomaterials in biological systems depends on both the nanomaterial properties and the exposure duration. Herein we used a multi-tier strategy to investigate the relationship between user-characterized multi-walled carbon nanotubes (MWCNTs) exposure duration and their induced biochemical and biomechanical effects on model human lung epithelial cells (BEAS-2B). Our results showed that exposure to MWCNTs leads to time-dependent intracellular uptake and generation of reactive oxygen species (ROS), along with time-dependent gradual changes in cellular biomechanical properties. In particular, the amount of internalized MWCNTs followed a sigmoidal curve with the majority of the MWCNTs being internalized within 6h of exposure; further, the sigmoidal uptake correlated with the changes in the oxidative levels and cellular biomechanical properties respectively. Our study provides new insights into the time-dependent induced toxicity caused by exposure to occupationally relevant doses of MWCNTs and could potentially help establish bases for early risk assessments of other nanomaterials toxicological profiles.

Electronic platform for real-time multi-parametric analysis of cellular behavior post-exposure to single-walled carbon nanotubes

Single-walled carbon nanotubes (SWCNTs) implementation in a variety of biomedical applications from bioimaging, to controlled drug delivery and cellular-directed alignment for muscle myofiber fabrication, has raised awareness of their potential toxicity. Nanotubes structural aspects which resemble asbestos, as well as their ability to induce cyto and genotoxicity upon interaction with biological systems by generating reactive oxygen species or inducing membrane damage, just to name a few, have led to focused efforts aimed to assess associated risks prior their user implementation. In this study, we employed a non-invasive and real-time electric cell impedance sensing (ECIS) platform to monitor behavior of lung epithelial cells upon exposure to a library of SWCNTs with user-defined physico-chemical properties. Using the natural sensitivity of the cells, we evaluated SWCNT-induced cellular changes in relation to cell attachment, cell-cell interactions and cell viability respectively. Our methods have the potential to lead to the development of standardized assays for risk assessment of other nanomaterials as well as risk differentiation based on the nanomaterials surface chemistry, purity and agglomeration state.

In vitro and in vivo toxicology of bare and PEGylated fluorescent carbonaceous nanodots in mice and zebrafish: the potential relationship with autophagy

The toxicity of CDs in mice and zebrafish and the potential relationship between toxicity and autophagy was evaluated.

Graphene oxide supported gold nanoclusters for the sensitive and selective detection of nitrite ions

Nitrite selectively reacts to red fluorescent gold nanoclusters supported on blue fluorescent graphene oxide sheet and leads to a ratiometric fluorescence color change.

A dual targeting cyclodextrin/gold nanoparticle conjugate as a scaffold for solubilization and delivery of paclitaxel

A cyclodextrin/gold nanoparticle conjugate was constructed as a dual targeting scaffold for solubilization and delivery of anticancer drug paclitaxel.

The kinetics and mechanism of the oxidation of pyruvate ion by hypochlorous acid

Kinetic experiments and DFT calculations confirm a concerted oxygen atom transfer mechanism for the oxidation of pyruvic acid by HOCl.

Graphene and graphene oxide: advanced membranes for gas separation and water purification

Advanced membrane systems with excellent permeance are important for controllable separation processes, such as gas separation and water purification.

AgAuPt nanocages for highly sensitive detection of hydrogen peroxide

AgAuPt hybrid nanocages modified electrode showed high sensitivity for the detection of hydrogen peroxide.

Suppression of protein aggregation by gold nanoparticles: a new way to store and transport proteins

Suppression of protein aggregation by gold nanoparticles under physiological conditions and its dependence on the nanoparticle size.

Analysis of affinities between specific biological ligands using atomic force microscopy

We used atomic force microscopy to rank the energetics of biomolecular recognition events of protein–ligand complexes.

A Systematic Study of the Catalytic Behavior at Enzyme–Metal-Oxide Nanointerfaces

Metal-oxide nanoparticles with high surface area, controllable functionality and thermal and mechanical stability provide high affinity for enzymes when the next generation of biosensor applications are being considered. We report on the synthesis of metal-oxide-based nanoparticles (with different physical and chemical properties) using hydrothermal processing, photo-deposition and silane functionalization. Physical and chemical properties of the user-synthesized nanoparticles were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Raman scattering, respectively. Thus, characterized metal-oxide-based nanoparticles served as nanosupports for the immobilization of soybean peroxidase enzyme (a model enzyme) through physical binding. The enzyme–nanosupport interface was evaluated to assess the optimum nanosupport characteristics that preserve enzyme functionality and its catalytic behavior. Our results showed that both the nanosupport geometry and its charge influence the functionality and catalytic behavior of the bio-metal-oxide hybrid system.

Enzyme catalytic efficiency: a function of bio-nano interface reactions

Biocatalyst immobilization onto carbon-based nanosupports has been implemented in a variety of applications ranging from biosensing to biotransformation and from decontamination to energy storage. However, retaining enzyme functionality at carbon-based nanosupports was challenged by the non-specific attachment of the enzyme as well as by the enzyme-enzyme interactions at this interface shown to lead to loss of enzyme activity. Herein, we present a systematic study of the interplay reactions that take place upon immobilization of three pure enzymes namely soybean peroxidase, chloroperoxidase, and glucose oxidase at carbon-based nanosupport interfaces. The immobilization conditions involved both single and multipoint single-type enzyme attachment onto single and multi-walled carbon nanotubes and graphene oxide nanomaterials with properties determined by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Our analysis showed that the different surface properties of the enzymes as determined by their molecular mapping and size work synergistically with the carbon-based nanosupports physico-chemical properties (i.e., surface chemistry, charge and aspect ratios) to influence enzyme catalytic behavior and activity at nanointerfaces. Knowledge gained from these studies can be used to optimize enzyme-nanosupport symbiotic reactions to provide robust enzyme-based systems with optimum functionality to be used for fermentation, biosensors, or biofuel applications.