Daniel Roxbury

Memorial Sloan Kettering Cancer Center | MSKCC · Department of Pharmacology

A challenge of particular interest in the fields of biosensing and bioimaging is the acquisition of real-time readouts of localized bioanalyte concentration through biomaterials and live tissue in a minimally-invasive fashion. The intrinsic fluorescence of single-walled carbon nanotubes (SWCNTs), which exhibits exceptional photostability, near-infr...

Macrophages play a critical role in the immune system, as both pro and anti-inflammatory immune cells these are the first line of defense from foreign bodies. Although methods for identifying Macrophage Phenotype (M1, M2) currently exist, these methods are limiting to factors like time, cost, operational training, and sample size. Cost and time eff...

Single-walled carbon nanotubes (SWCNTs) have been at the forefront of research for well over a decade due to their unique optical properties. Specifically, the inherent and photostable fluorescence of SWCNTs has been used to create sensitive near-infrared (NIR) sensors for a variety of target analytes, such as dopamine and cholesterol. However, mos...

Supramolecular hybrids of DNA and single-walled carbon nanotubes (SWCNTs) have been introduced in numerous biosensing applications due to their unique optical properties. Recent aqueous two-phase (ATP) purification methods for SWCNTs have gained popularity by introducing specificity and homogeneity into the sensor design process. Using murine macro...

Significant advances have been made in fields such as nanotechnology and biomedicine using the unique properties of single-walled carbon nanotubes (SWCNTs). Specifically, SWCNTs are used as near-infrared fluorescence sensors in the solution phase to detect a wide array of biologically relevant analytes. However, solution-based sensing has several l...

The development of SWIR, or NIR II, imaging capabilities have significantly accelerated in the past few years. Initially most often developed out of necessity to observe specific phenomena or biosensors, NIR II instrumentation has evolved as a proper research field. Here we will focus on the latest advances in imaging and spectroscopic modalities,...

Nanomaterials are the subject of a range of biomedical, commercial, and environmental investigations involving measurements in living cells and tissues. Accurate quantification of nanomaterials, at the tissue, cell, and organelle levels, is often difficult, however, in part due to their inhomogeneity. Here, we propose a method that uses the diverse...

Applications of single-walled carbon nanotubes (SWCNTs) in bioimaging and biosensing have been limited by difficulties with isolating single-chirality nanotube preparations with desired functionalities. Unique optical properties, such as multiple narrow near-infrared bands and several modes of signal transduction, including solvatochromism and FRET...

In an effort to facilitate personalized medical approaches, the continuous and noninvasive monitoring of biochemical information using wearable technologies can enable a detailed understanding of an individual’s physiology. Reactive oxygen species (ROS) are a class of oxygen-containing free radicals which function in a wide range of biological proc...

In an effort to facilitate personalized medical approaches, the continuous and noninvasive monitoring of biochemical information using wearable technologies can enable a detailed understanding of an individual's physiology. Reactive oxygen species (ROS) are a class of oxygen‐containing free radicals that function in a wide range of biological proce...

Externally controllable drug delivery systems are crucial for a variety of biological applications where the dosage and timing of drug delivery need to be adjusted based on disease diagnosis and progression. Here, we have developed an externally controllable drug delivery system by combining three extensively used platforms: hydrogels, liposomes, a...

Intracellular vesicle trafficking involves a complex series of biological pathways used to sort, recycle, and degrade extracellular components, including engineered nanomaterials which gain cellular entry via active endocytic processes. A recent emphasis on routes of nanomaterial uptake has established key physicochemical properties which direct ce...

In an effort to facilitate personalized medical approaches, the continuous and noninvasive monitoring of biochemical information using wearable technologies can enable a detailed understanding of an individual's physiology. Reactive oxygen species (ROS) are a class of oxygen-containing free radicals which function in a wide range of biological proc...

The semiconducting single-walled carbon nanotube (SWCNT), noncovalently wrapped by a polymeric monolayer, is a nanoscale semiconductor-electrolyte interface under investigation for sensing, photonics, and photovoltaic applications. SWCNT complexes are routinely observed to sensitize various electrochemical/redox phenomena, even in the absence of an...

Non-covalent hybrids of single-stranded DNA and single-walled carbon nanotubes (SWCNTs) have demonstrated applications in biomedical imaging and sensing due to their enhanced biocompatibility and photostable, environmentally-responsive near-infrared (NIR) fluorescence. The fundamental properties of such DNA-SWCNTs have been studied to determine the...

Single-walled carbon nanotubes (SWCNTs) have recently been utilized as fillers that reduce the flammability and enhance the strength and thermal conductivity of material composites. Enhancing the thermal stability of SWCNTs is crucial when these materials are applied to high temperature applications. In many instances, SWCNTs are applied to composi...

Non-covalent hybrids of single-stranded DNA and single-walled carbon nanotubes (SWCNTs) have demonstrated applications in biomedical imaging and sensing due to their enhanced biocompatibility and photostable, environmentally-responsive near-infrared (NIR) fluorescence. The fundamental properties of such DNA-SWCNTs have been studied to determine the...

Single-walled carbon nanotubes exhibit unique photophysical properties that enable the detection of biomarkers, metabolites, and drugs in living cells, tissues, and organisms. The intrinsic near-infrared photoluminescence of nanotubes exhibits unique photostability and sensitivity to the local environment to transduce molecular binding events via c...

The intrinsic fluorescence of single-walled carbon nanotubes (SWCNTs), which exhibits exceptional photostability, near-infrared (NIR) tissue-penetrating emission, and microenvironmental sensitivity, makes them ideal candidates for a variety of biomedical imaging and sensing applications. Single-stranded DNA was found to disperse SWCNTs in water and...

Single-stranded DNA has been demonstrated to enable single-particle exfoliation of single-walled carbon nanotubes (SWCNTs) in aqueous environments as well as suppress their known toxicological effects. The resultant fundamental properties of DNA-SWCNT hybrids are significant when these nanomaterials are applied to mechanical and biological systems....

Modulation of the carbon nanotube photoluminescence band position has implications for applications such as sensing and imaging. Carbon nanotube photoluminescence solvatochromism, the hypsochromic or bathochromic shifting of nanotube emission, can be induced via changes in the local dielectric environment. We developed methods to modulate nanotube...

Single-walled carbon nanotubes (SWCNTs) functionalized with short single-stranded DNA have been extensively studied within the last decade for biomedical applications due to the high dispersion efficiency and intrinsic biocompatibility of DNA as well as the photostable and tunable fluorescence of SWCNTs. Characterization of their physical propertie...

The abnormal accumulation of lipids within the endolysosomal lumen occurs in many conditions, including lysosomal storage disorders, atherosclerosis, nonalcoholic fatty liver disease (NAFLD), and drug-induced phospholipidosis. Current methods cannot monitor endolysosomal lipid content in vivo, hindering preclinical drug development and research int...

The early detection of cancer could lead to vastly improved patient outcomes. We aim to identify cancer biomarkers within the body at early disease stages, permitting detection before symptoms arise. We are developing implantable nanosensors, using the unique optical properties of carbon nanotubes, to facilitate non-invasive detection via optical d...

With the advent of nanotechnology in the diagnosis and treatment of cancer, many questions arise regarding whether novel nanomedicines, nanosensors, and nanoimaging agents are detrimental to living things. At a fundamental level, minute variations in size, shape, and charge can have overwhelming effects on the manner in which a live cell or animal...

The detection of biomarkers and drugs in live cells and animals would allow for more effective studies of the dynamics of cancer and treatment. Toward these ends, single-walled carbon nanotube photoluminescence is suitable for measurements in live cells and in vivo, and nanotube near-infrared emission exhibits sensitivity to the local environment v...

Development of targeted nanoparticle drug carriers often requires complex synthetic schemes involving both supramolecular self-assembly and chemical modification. These processes are generally difficult to predict, execute, and control. We describe herein a targeted drug delivery system that is accurately and quantitatively predicted to self-assemb...

Lipid accumulation within the lumen of endolysosomal vesicles is observed in various pathologies including atherosclerosis, liver disease, neurological disorders , lysosomal storage disorders, and cancer. Current methods cannot measure lipid flux specifically within the lysosomal lumen of live cells. We developed an optical reporter, composed of a...

Lipid accumulation within the lumen of endolysosomal vesicles is observed in various pathologies including atherosclerosis, liver disease, neurological disorders, lysosomal storage disorders, and cancer. Current methods cannot measure lipid flux specifically within the lysosomal lumen of live cells. We developed an optical reporter, composed of a p...

MicroRNAs and other small oligonucleotides in biofluids are promising biomarkers, but conventional assays require complex processing steps unsuitable for point-of-care assays or implantable/wearable sensors. Single-walled carbon nanotubes are an ideal material for implantable sensors due to emission in the near-infrared spectral region, photostabil...

Short single-stranded DNA (ssDNA) has emerged as the natural polymer of choice for non-covalently functionalizing photoluminescent single-walled carbon nanotubes. In addition, specific empirically identified DNA sequences can be used to separate single species (chiralities) of nanotubes with exceptionally high purity. Currently, only limited genera...

The intrinsic photoluminescence properties of semi-conducting single-walled carbon nanotubes (SWCNTs), including indefinite photostability, high spectral diversity, environmental sensitivity, and near infrared emission, have recently been exploited for various applications ranging from optical strain sensors to biomedical imaging labels and probes....

The real-time and spatially-resolved detection and identification of analytes present important goals for next-generation nanoscale sensors. Low-dimensional nanomaterials may improve the detection of molecular binding phenomena and result in better quantification of disease biomarkers and other bioanalytes. Cylindrical graphene provides a non-degra...

The real-time and spatially-resolved detection and identification of analytes in biological media present important goals for next-generation nanoscale probes and sensors. To this end, we employ the intrinsic near-infrared fluorescence of single-walled carbon nanotubes which is photostable yet sensitive to the immediate environment. To build biomed...

The photoluminescence of single-walled carbon nanotubes may facilitate quantification of analytes within complex environments. To design quantitative sensors using carbon nanotubes, greater understanding of the optical modulation of their photoluminescence is necessary. On exploring the modulation of nanotubes, we found new methods to enable unprec...

The properties of single-walled carbon nanotubes make them well-suited for potential uses in imaging and sensing applications. Their environmentally-sensitive, photostable emission does not exhibit the blinking phenomenon observed with other nanostructures such as quantum dots, and they emit in the near-infrared where tissue autofluorescence is low...

Single-walled carbon nanotubes are of interest in biomedicine for imaging and molecular sensing applications and as shuttles for various cargos such as chemotherapeutic drugs, peptides, proteins, and oligonucleotides. Carbon nanotube surface chemistry can be modulated for subcellular targeting while preserving photoluminescence for label-free visua...

MicroRNAs and other small oligonucleotides in biofluids are promising disease biomarkers, yet conventional assays require complex processing steps that are unsuitable for point-of-care testing or for implantable or wearable sensors. Single-walled carbon nanotubes are an ideal material for implantable sensors, owing to their emission in the near-inf...

Electronic and biological applications of carbon nanotubes can be highly dependent on the species (chirality) of nanotube, purity, and concentration. Existing bulk methods, such as absorbance spectroscopy, can quantify sp2 carbon based on spectral bands, but nanotube length distribution, defects, and carbonaceous impurities can complicate quantific...

In the fifteen years following the discovery of single-walled carbon nanotube (SWCNT) photoluminescence, investigators have made significant progress in their understanding of the phenomenon and toward the development of applications. The intrinsic potential of semiconducting carbon nanotubes – a family of bright, photostable near infrared (NIR) fl...

The intrinsic near-infrared photoluminescence (fluorescence) of single-walled carbon nanotubes exhibits unique photostability, narrow bandwidth, penetration through biological media, environmental sensitivity, and both chromatic variety and range. Biomedical applications exploiting this large family of fluorophores will require the spectral and spa...

The real-time and spatially-resolved detection and identification of analytes in biological media present important goals for next-generation nanoscale probes and sensors. To this end, we employ the intrinsic near-infrared fluorescence of single-walled carbon nanotubes which is photostable yet sensitive to the immediate environment. Analyte identif...

The near-infrared photoluminescence from non-covalently dispersed single-walled carbon nanotubes (SWCNT) is optimally suited to probe distinct classes of biological environments. With aspect ratios of >100:1, nanotubes present an opportunity to observe atypical interactions between linear filamentous particles and three-dimensional biological envir...

The transport, storage and degradation of macromolecules in cells represent tightly regulated processes that are vital to cellular function. Cells and organisms that are unable to regulate these processes will exhibit deleterious phenotypes such as impaired nervous system or liver function. Developing treatments for such disorders is challenging, d...

The intrinsic near-infrared photoluminescence of semiconducting single-walled carbon nanotubes exhibits environmental sensitivity which has been employed to detect various analytes in complex environments, including biological media. To build biomedical technologies that employ carbon nanotube photoluminescence, a better understanding of the optica...

Single-walled carbon nanotubes exhibit photostable near-infrared photoluminescence with excitation and emission energies that respond to fluctuations in the micro-environment. In the creation of robust nanotube-based optical sensors, it is desirable to identify shifts in excitation and emission of an ensemble nanotube sample (HiPco) in response to...

Semiconducting single-walled carbon nanotubes (SWCNTs) exhibit unique photophysical processes from the visible to near-infrared that are ascribed to excitation and decay of excitonic transitions. Here we show that polyelectrolytic dispersants and aqueous electrolytes interact directly with charge carriers in the semiconducting nanotubes, resulting...

Since the onset and progression of cancer and many other diseases involve dysregulation of certain sub-cellular compartments, accurate visualization of events using probes localized in sub-cellular organelles would facilitate the understanding of disease processes. Molecular probes based on single-walled carbon nanotubes (SWCNTs) are ideal for imag...

Single-walled carbon nanotubes have a number of properties of interest for their development as sensors and molecular probes for use in biological media. They are inherently fluorescent in the near-infrared “tissue transparent window” and do not photobleach. Multiple, optically distinct nanotube species can be used for extensive multiplexing in a s...

The near-infrared photoluminescence from non-covalently dispersed single-walled carbon nanotubes (SWCNT) is optimally suited to probe distinct classes of biological environments. At the single cell level, DNA-nanotubes enter live cells via endocytosis at 37°C and remain within the endosomal pathway, with their final localization exclusively in the...

The intrinsic near-infrared photoluminescence (fluorescence) of single-walled carbon nanotubes exhibits unique photostability, narrow bandwidth, penetration through biological media, environmental sensitivity, and both chromatic variety and range. Biomedical applications exploiting this large family of fluorophores will require the spectral and spa...

The intrinsic photoluminescence (fluorescence) of carbon nanotubes exhibits unique photostability, narrow bandwidth, near-infrared penetration of biological media, and environmental sensitivity. Advanced biological applications will require the spectral and spatial resolution of individual (n,m) nanotube species’ fluorescence and its modulation wit...

The environmentally sensitive and intrinsically photostable near-infrared emission of single-walled carbon nanotubes (SWCNTs) shows promise for multiplexed, photostable, near-infrared (nIR) optical probes and molecular sensors. Use of nanotubes for such purposes requires the ability to simultaneously modulate nanotube fluorescence and functionally...

The intrinsic near-infrared photoluminescence from a single nanotube can be detected within a live cell via epifluorescence. As the emission spectrum of a nanotube is exquisitely modulated by the immediate microenvironment of the nanotube, information contained in the peak emission wavelength, intensity, and full width half maximum can reflect phys...

Proper transport, storage and degradation of macromolecules in cells is vital to their function. Cells and organisms that are unable to properly carry out these processes may exhibit deleterious phenotypes such as impaired endoplasmic reticulum and mitochondrial function. Currently, very few therapies exist for the treatment of such disorders due,...

The use of single-walled carbon nanotubes (SWCNTs) as near-infrared optical probes and sensors require the ability to simultaneously modulate nanotube fluorescence and functionally derivatize the nanotube surface using noncovalent methods. We synthesized a small library of polycarbodiimides to noncovalently encapsulate SWCNTs with a diverse set of...

Biological polymers hybridized with single-walled carbon nanotubes (SWCNTs) have elicited much interest recently for applications in SWCNT-based sorting as well as biomedical imaging, sensing, and drug delivery. Recently, de novo designed peptides forming a coiled-coil structure have been engineered to selectively disperse SWCNT of a certain diamet...

The single-stranded DNA to single-walled carbon nanotube (SWCNT) hybrid continues to attract significant interest as an exemplary biological molecule-nanomaterial conjugate. In addition to their many biomedical uses, such as in vivo sensing and delivery of molecular cargo, DNA-SWCNT hybrids enable the sorting of SWCNTs according to their chirality....

Several applications of single-walled carbon nanotubes (SWCNT) as nanovectors in biological systems have been reported, and several molecular pathways of cellular entry have been proposed. We employed transmission electron microscopy, confocal fluorescent microscopy, and UV-vis spectroscopic analysis to confirm the internalization of DNA-SWCNT in h...

Hybrids of biological molecules and single-walled carbon nanotubes (SWCNT) have proven useful for SWCNT sorting and are enabling several biomedical applications in sensing, imaging, and drug delivery. In the DNA-SWCNT system, certain short (10-20mer) sequences of single-stranded DNA recognize specific SWCNT, allowing the latter to be sorted from a...

It is known that single-stranded DNA adopts a helical wrap around a single-walled carbon nanotube (SWCNT), forming a water-dispersible hybrid molecule. The ability to sort mixtures of SWCNTs based on chirality (electronic species) has recently been demonstrated using special short DNA sequences that recognize certain matching SWCNTs of specific chi...

It has been shown that, under certain conditions, single-stranded DNA (ssDNA) preferentially wraps in a helical fashion around carbon nanotubes (CNTs), forming a water-dispersible hybrid. Recently, its ability to sort mixtures of CNTs based on chirality has been demonstrated using special short ssDNA sequences. It is believed the emergence of DNA s...

The DNA-single-walled carbon nanotube (SWCNT) hybrid molecule has attracted significant attention recently for its ability to disperse and sort SWCNTs according to their chirality. Key for utilizing their unique properties is an understanding of the structure of DNA adsorbed on the SWCNT surface, which we study here using molecular simulations. Usi...

The ability to sort mixtures of carbon nanotubes (CNTs) based on chirality has recently been demonstrated using special short DNA sequences that recognize certain matching CNTs of specific chirality. In this work, we report on a study of the relationship between recognition sequences and the strength of their binding to the recognized CNT. We have...

It has recently been discovered that certain short DNA sequences recognize specific carbon nanotubes (CNTs), allowing a mixture to be sorted into individual types. A novel β-sheet and β-barrel secondary DNA motif has been proposed as the structural basis for this recognition. In this study, using molecular simulation, we investigate a class of DNA...