A5012511525- Cellular Mechanics and Interactions
- Force Microscopy Techniques and Applications
- Neuroscience and Neural Engineering
- Carbon Nanotubes in Composites
- Axon Guidance and Neuronal Signaling
- Silk-based biomaterials and applications
- 3D Printing in Biomedical Research
- Polymer Surface Interaction Studies
- Mechanical and Optical Resonators
- Conducting polymers and applications
- Nanofabrication and Lithography Techniques
- Nerve injury and regeneration
- Analytical Chemistry and Sensors
- Nanopore and Nanochannel Transport Studies
- Graphene research and applications
- Molecular Junctions and Nanostructures
- Electrospun Nanofibers in Biomedical Applications
- Microtubule and mitosis dynamics
- Advanced Materials and Mechanics
- Advanced biosensing and bioanalysis techniques
- Advanced Sensor and Energy Harvesting Materials
- Diatoms and Algae Research
- Platelet Disorders and Treatments
- Neural dynamics and brain function
- Biochemical and Structural Characterization
Tufts University
2015-2024
Medford Radiology Group
2019
Madison Group (United States)
2011
University of Wisconsin–Madison
2007-2009
Princeton University
2006-2008
Elettra-Sincrotrone Trieste S.C.p.A.
2007-2008
University of Pennsylvania
2003-2007
Scuola Internazionale Superiore di Studi Avanzati
2007
We demonstrate a new, versatile class of nanoscale chemical sensors based on single-stranded DNA (ss-DNA) as the recognition site and single-walled carbon nanotube field effect transistors (swCN-FETs) electronic read-out component. swCN-FETs with coating ss-DNA respond to gas odors that do not cause detectable conductivity change in bare devices. Responses ss-DNA/swCN-FETs differ sign magnitude for different gases can be tuned by choosing base sequence ss-DNA. ss-DNA/swCN-FET detect variety...
We fabricate and electrically characterize electrospun nanofibers of doped polyaniline/polyethylene oxide (PAn/PEO) blend with sub-30 nm diameter. Fiber diameters near 5 are obtained for optimized process parameters. Scanning conductance microscopy (SCM) shows that fibers diameter below 15 insulating; the small may allow complete dedoping in air or be smaller than phase-separated grains PAn PEO. Electrical contacts to made by shadow mask evaporation no chemical thermal damage fibers. Single...
Abstract There is great need for soft biomaterials that match the stiffness of human tissues tissue engineering and regeneration. Hydrogels are frequently employed extracellular matrix functionalization to provide appropriate mechanical cues. It challenging, however, achieve structural integrity retain bioactive molecules in hydrogels complex formation may take months develop. This work aims investigate biochemical characteristics silk engineering, specifically nervous system. The 1 8%...
Scalable computational modelling tools are required to guide the rational design of complex hierarchical materials with predictable functions. Here, we utilize mesoscopic modelling, integrated genetic block copolymer synthesis and bioinspired spinning process, demonstrate de novo that incorporates chemistry, processing material characterization. We find intermediate hydrophobic/hydrophilic ratios observed in natural spider silks longer chain lengths lead outstanding silk fibre formation....
We present a quantitative model for phase shifts observed in scanning conductance microscopy and show excellent agreement with data on samples of (conducting) single wall carbon nanotubes insulating poly(ethylene oxide) (PEO) nanofibers. The takes into account due to the electrostatic (capacitive) forces exerted tip by sample substrate, using simple approximate geometries. Data large diameter, conducting doped polyaniline/PEO nanofibers are qualitatively explained. This approach is used...
Abstract The mechanical properties of spider silks drive interest as sources new materials. However, there remains a lot to learn regarding the relationships between sequence, structure, and properties. In order predict types sequence–functional relationships, synthesis–characterization–computation are integrated using recombinant silk‐like block copolymers. Two designs studied, both with origins from Nephila clavipes . These proteins studied experimentally in silico understand sequence...
This paper describes a series of thiophene-based conjugated polymers that become insoluble upon irradiation with ultraviolet light. Stille or Suzuki reactions appropriately substituted 2,5-bromothiophene derivatives yielded terthiophene and polythiophene either o-nitrobenzyl (ONB) ester ONB ether photolabile side chains n-octyl substituents. Light-induced cleavage these light at 365 nm cleaves the octyl responsible for solubilization away from main chains, rendering them insoluble....
Megakaryocytes (MK) in the bone marrow (BM) are immersed a network of extracellular matrix components that regulates platelet release into circulation. Combining biological and bioengineering approaches, we found activation transient receptor potential cation channel subfamily V member 4 (TRPV4), mechano-sensitive ion channel, is induced upon MK adhesion on softer matrices. This response promoted production by triggering cascade events lead to calcium influx, β1 integrin internalization, Akt...
We demonstrate a versatile class of nanoscale chemical sensors based on single-stranded DNA (ssDNA) for recognition and single-walled carbon nanotube field effect transistors (SWNT FETs) electronic read-out. SWNT FETs with coating ssDNA respond to vapours that cause no detectable conductivity change in bare devices. The gases tested are methanol, trimethylamine, propionic acid, dimethylmethylphosphonate dinitrotoluene. Sensor responses differ sign magnitude different can be tuned by choice...
Susceptibility of mammalian cells against harsh processing conditions limit their use in cell transplantation and tissue engineering applications. Besides modulation the microenvironment, encapsulation within hydrogel microbeads attract attention for cytoprotection through physical isolation encapsulated cells. The formulations used microencapsulation are largely dominated by ionically crosslinked alginate (Alg), which suffer from low structural stability under physiological culture poor...
Free-standing, stimuli-responsive polyelectrolyte multilayer films enabled by light-induced degradation of sacrificial compartments are introduced. Two examples described: i) a triple responsive film that uses light, redox, and pH for different functions, ii) wavelengths light functions. This approach to multiresponsive materials offers simple design chemical synthesis while enabling stimuli perform separate functions in the same material.
When studying the mechanical properties of cells by an indentation technique, it is important to take into account nontrivial pericellular interface (or "brush") which includes a coating and corrugation membrane (microvilli microridges). Here we use atomic force microscopy (AFM) study mechanics cortical neurons taking presence above brush surrounding cell soma. We perform systematic both layer underlying neuron soma demonstrate that likely responsible for low elastic modulus (<1 kPa)...
Neuronal cells change their growth properties in response to external physical stimuli such as variations temperature, stiffness of the substrate, or topographical guidance cues. Detailed knowledge mechanisms that control these biomechanical responses is necessary for understanding basic principles underlie neuronal and regeneration. Here, we present elasticity maps living cortical neurons (embryonic rat) a function correlate locations internal structural components cytoskeleton. Neurons...
We use atomic force microscopy (AFM) to perform a systematic quantitative characterization of the elastic modulus and dielectric constant poly(L-lactic acid) electrospun nanofibers (PLLA), as well composites PLLA fibers with 1.0 wt% embedded multiwall carbon nanotubes (MWCNTs–PLLA). The moduli are measured in fiber skin region via AFM nanoindentation, constants determined by measuring phase shifts obtained electrostatic (EFM). find that average value for is (9.8 ± 0.9) GPa, which factor 2...
We demonstrate that the Atomic Force Microscope (AFM) can be used to immobilize a dicysteine-terminated protein (Maltose Binding Protein, MBP-cys-cys for short) at well-defined locations directly on gold substrates via nanografting and characterize in situ bioactivity of these proteins within fabricated nanopatterns. This method exploits high spatial orientational control monolayer assembly allowed by nanografting, combined with sensitivity AFM detecting ligand-binding events. The...
Detailed knowledge of how the surface physical properties, such as mechanics, topography and texture influence axonal outgrowth guidance is essential for understanding processes that control neuron development, formation functional neuronal connections nerve regeneration. Here we synthesize asymmetric surfaces with well-controlled perform a systematic experimental theoretical investigation on these substrates. We demonstrate unidirectional bias imparted by ratchet-based quantify...
Reduced Graphene Oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the gating effects in RGO-based sensors. The gas devices are patterned field-effect transistor geometry, by dielectrophoretic assembly RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show these sensors display highly selective and reversible responses to measured analytes, as well fast response recovery...
This paper describes photosensitive polyelectrolyte multilayers (PEMs), constructed using layer-by-layer (LbL) self-assembly, which contain polymers that comprise combinations of photocleavable methacrylate esters and photoinert cationic esters. The solubility these in aqueous base depends upon irradiation with either ultraviolet or visible light. PEMs dialkylaminocoumarin groups dissolve light, while analogous films nitrobenzyl ester-substituted UV Wavelength-selective release fluorescent...
Encapsulation of single cells is a powerful technique used in various fields, such as regenerative medicine, drug delivery, tissue regeneration, cell-based therapies, and biotechnology. It offers method to protect by providing cytocompatible coatings strengthen against mechanical environmental perturbations. Silk fibroin, derived from the silkworm Bombyx mori, promising protein biomaterial for cell encapsulation due cytocompatibility capacity maintain functionality. Here, THP-1 cells, human...