20 research outputs found
Coupling of Semiconductor Nanowires with Neurons and Their Interfacial Structure
We report on the compatibility of various nanowires with hippocampal neurons and the structural study of the neuron–nanowire interface. Si, Ge, SiGe, and GaN nanowires are compatible with hippocampal neurons due to their native oxide, but ZnO nanowires are toxic to neuron due to a release of Zn ion. The interfaces of fixed Si nanowire and hippocampal neuron, cross-sectional samples, were prepared by focused ion beam and observed by transmission electron microscopy. The results showed that the processes of neuron were adhered well on the nanowire without cleft
Near-field Electrical Detection of Optical Plasmons and Single Plasmon Sources
Photonic circuits can be much faster than their electronic counterparts, but
they are difficult to miniaturize below the optical wavelength scale. Nanoscale
photonic circuits based on surface plasmon polaritons (SPs) are a promising
solution to this problem because they can localize light below the diffraction
limit. However, there is a general tradeoff between the localization of an SP
and the efficiency with which it can be detected with conventional far-field
optics. Here we describe a new all-electrical SP detection technique based on
the near-field coupling between guided plasmons and a nanowire field-effect
transistor. We use the technique to electrically detect the plasmon emission
from an individual colloidal quantum dot coupled to an SP waveguide. Our
detectors are both nanoscale and highly efficient (0.1 electrons/plasmon), and
a plasmonic gating effect can be used to amplify the signal even higher (up to
50 electrons/plasmon). These results enable new on-chip optical sensing
applications and are a key step towards "dark" optoplasmonic nanocircuits in
which SPs can be generated, manipulated, and detected without involving
far-field radiation.Comment: manuscript followed by supplementary informatio
Orientation and Training of New Biobank Personnel
The personnel who operate a biomedical biobank should function as a unit to efficiently manage the numerous types of biospecimens that are to be utilized for both clinical and research purposes. Therefore, new staff must be appropriately trained before becoming fully integrated into the work environment. This chapter focuses on several key aspects to this training that should be completed by all personnel. This first step is an orientation where the new trainee is provided with the priorities and expectations of the biobank. The next and perhaps most important step is training on the various safety precautions. The trainee should learn how to protect patient privacy if human biospecimens are involved. They should gain a basic understanding of different types of biospecimens and their vulnerabilities to suboptimal storage conditions. The trainee must learn the various aspects of the day to day work which encompasses the methods and equipment needed for procuring, labeling, handling, tracking, storing, disbursing, and shipping biospecimens. They should become familiar with aspects of quality assurance
Compact biocompatible quantum dots functionalized for cellular imaging.
We present a family of water-soluble quantum dots (QDs) that exhibit low nonspecific binding to cells, small hydrodynamic diameter, tunable surface charge, high quantum yield, and good solution stability across a wide pH range. These QDs are amenable to covalent modification via simple carbodiimide coupling chemistry, which is achieved by functionalizing the surface of QDs with a new class of heterobifunctional ligands incorporating dihydrolipoic acid, a short poly(ethylene glycol) (PEG) spacer, and an amine or carboxylate terminus. The covalent attachment of molecules is demonstrated by appending a rhodamine dye to form a QD-dye conjugate exhibiting fluorescence resonance energy transfer (FRET). High-affinity labeling is demonstrated by covalent attachment of streptavidin, thus enabling the tracking of biotinylated epidermal growth factor (EGF) bound to EGF receptor on live cells. In addition, QDs solubilized with the heterobifunctional ligands retain their metal-affinity driven conjugation chemistry with polyhistidine-tagged proteins. This dual functionality is demonstrated by simultaneous covalent attachment of a rhodamine FRET acceptor and binding of polyhistidine-tagged streptavidin on the same nanocrystal to create a targeted QD, which exhibits dual-wavelength emission. Such emission properties could serve as the basis for ratiometric sensing of the cellular receptor's local chemical environment
Identification of novel mutations in FFPE lung adenocarcinomas using DEPArray sorting technology and next-generation sequencing
Growth kinetics controlled rational synthesis of germanium nanotowers in chemical vapor deposition
Direct probe of spectral inhomogeneity reveals synthetic tunability of single-nanocrystal spectral linewidths
The spectral linewidth of an ensemble of fluorescent emitters is dictated by the combination of single-emitter linewidths and sample inhomogeneity. For semiconductor nanocrystals, efforts to tune ensemble linewidths for optical applications have focused primarily on eliminating sample inhomogeneities, because conventional single-molecule methods cannot reliably build accurate ensemble-level statistics for single-particle linewidths. Photon-correlation Fourier spectroscopy in solution (S-PCFS) offers a unique approach to investigating single-nanocrystal spectra with large sample statistics and high signal-to-noise ratios, without user selection bias and at fast timescales. With S-PCFS, we directly and quantitatively deconstruct the ensemble linewidth into contributions from the average single-particle linewidth and from sample inhomogeneity. We demonstrate that single-particle linewidths vary significantly from batch to batch and can be synthetically controlled. These findings delineate the synthetic challenges facing underdeveloped nanomaterials such as InP and InAs core–shell particles and introduce new avenues for the synthetic optimization of fluorescent nanoparticles.United States. Dept. of Energy. Office of Basic Energy Sciences (Division of Materials Sciences and Engineering Grant DE-FG02-07ER46454)National Institutes of Health (U.S.) (Award P41EB015871-26A1)National Science Foundation (U.S.). Graduate Research Fellowship ProgramHertz Foundatio