Building a culture of responsible neurotech: Neuroethics as socio-technical challenges.

Scientists around the globe are joining the race to achieve engineering feats to read, write, modulate, and interface with the human brain in a broadening continuum of invasive to non-invasive ways. The expansive implications of neurotechnology for our conception of health, mind, decision-making, and behavior has raised social and ethical considerations that are inextricable from neurotechnological progress. We propose "socio-technical" challenges as a framing to integrate neuroethics into the engineering process.

Functionally Distinct Neuronal Ensembles within the Memory Engram.

Memories are believed to be encoded by sparse ensembles of neurons in the brain. However, it remains unclear whether there is functional heterogeneity within individual memory engrams, i.e.

Progress in neuromodulation of the brain: A role for magnetic nanoparticles?

The field of neuromodulation is developing rapidly. Current techniques, however, are still limited as they i) either depend on permanent implants, ii) require invasive procedures, iii) are not cell-type specific, iv) involve slow pharmacokinetics or v) have a restricted penetration depth making it difficult to stimulate regions deep within the brain. Refinements into the different fields of neuromodulation are thus needed.

Ion-Switchable Quantum Dot Förster Resonance Energy Transfer Rates in Ratiometric Potassium Sensors.

The tools for optically imaging cellular potassium concentrations in real-time are currently limited to a small set of molecular indicator dyes. Quantum dot-based nanosensors are more photostable and tunable than organic indicators, but previous designs have fallen short in size, sensitivity, and selectivity. Here, we introduce a small, sensitive, and selective nanosensor for potassium measurements.

Nanoscale morphology revealed at the interface between colloidal quantum dots and organic semiconductor films.

The degree of interpenetration at the interface between colloidal quantum dots (QDs) and organic semiconductor molecules commonly employed in hybrid light-emitting devices (QD-LEDs) has been examined using tapping-mode atomic force microscopy. Both phase separation-driven and Contact Printing-enabled QD/semiconductor heterojunction fabrication methodologies lead to significant QD embedment in the underlying organic film with the greatest degree of QD penetration observed for QD monolayers that have been contact printed. The relative performance of QD-LEDs fabricated via three different methods using the same materials set has also been investigated.

Quantum dot light-emitting devices with electroluminescence tunable over the entire visible spectrum.

Improvements in quantum dot light-emitting device (QD-LED) performance are achieved by the choice of organic charge transporting layers, by use of different colloidal QDs for the different parts of the visible spectrum, and by utilizing a recently demonstrated robust QD deposition method. Spectrally narrow electroluminescence of our QD-LEDs is tuned over the entire visible wavelength range from lambda = 460 nm (blue) to lambda = 650 nm (deep red). By printing close-packed monolayers of different QD types inside an identical QD-LED structure, we demonstrate that different color QD-LEDs with QDs of different chemistry can be fabricated on the same substrate.

Contact printing of quantum dot light-emitting devices.

We demonstrate a solvent-free contact printing process for deposition of patterned and unpatterned colloidal quantum dot (QD) thin films as the electroluminescent layers within hybrid organic-QD light-emitting devices (QD-LEDs). Our method benefits from the simplicity, low cost, and high throughput of solution-processing methods, while eliminating exposure of device structures to solvents. Because the charge transport layers in hybrid organic/inorganic QD-LEDs consist of solvent-sensitive organic thin films, the ability to avoid solvent exposure during device growth, as presented in this study, provides a new flexibility in choosing organic materials for improved device performance.

Electroluminescence from a mixed red-green-blue colloidal quantum dot monolayer.

We demonstrate light emitting devices (LEDs) with a broad spectral emission generated by electroluminescence from a mixed-monolayer of red, green, and blue emitting colloidal quantum dots (QDs) in a hybrid organic/inorganic structure. The colloidal QDs are reproducibly synthesized and yield high luminescence efficiency materials suitable for LED applications. Independent processing of the organic charge transport layers and the QD luminescent layer allows for precise tuning of the emission spectrum without changing the device structure, simply by changing the ratio of different color QDs in the active layer.