Heterojunction and superlattice formation is essential for many potential applications of semiconductor nanowires in nanoscale optoelectronics. We have developed a hybrid pulsed laser ablation/chemical capor deposition (PLA-CVD) process for the synthesis of semiconductor nanowires with longitudinal ordered heterostructures. The laser ablation process generates a programmable pulsed vapor source, which enables the nanowire growth in a block-by-block fashion with a well-defined compositional profile along the wire axis. Single-crystalline nanowires with longitudinal Si/SiGe superlattice structure have been successfully synthesized. This unique class of heterostructured one-dimensional nanostructures holds great potential in applications such as light emitting devices and thermoelectrics.

We report a nanofluidic transistor based on a metal-oxide-solution (MOSol) system that is similar to a metal-oxide-semiconductor field-effect transistor (MOSFET). Using a combination of fluorescence and electrical measurements, we demonstrate that gate voltage modulates the concentration of ions and molecules in the channel and controls the ionic conductance. Our results illustrate the efficacy of field-effect control in nanofluidics, which could have broad implications on integrated nanofluidic circuits for manipulation of ions and biomolecules in sub-femtoliter volumes.

Inflammation is a beneficial host response to infection but can contribute to inflammatory disease if unregulated. The TH17 lineage of T helper (TH) cells can cause severe human inflammatory diseases. These cells exhibit both instability (they can cease to express their signature cytokine, IL-17A)1 and plasticity (they can start expressing cytokines typical of other lineages)1,2 upon in vitro re-stimulation. However, technical limitations have prevented the transcriptional profiling of pre- and post-conversion TH17 cells ex vivo during immune responses. Thus, it is unknown whether TH17 cell plasticity merely reflects change in expression of a few cytokines, or if TH17 cells physiologically undergo global genetic reprogramming driving their conversion from one T helper cell type to another, a process known as transdifferentiation3,4. Furthermore, although TH17 cell instability/plasticity has been associated with pathogenicity1,2,5, it is unknown whether this could present a therapeutic opportunity, whereby formerly pathogenic TH17 cells could adopt an anti-inflammatory fate. Here we used two new fate-mapping mouse models to track TH17 cells during immune responses to show that CD4+ T cells that formerly expressed IL-17A go on to acquire an anti-inflammatory phenotype. The transdifferentiation of TH17 into regulatory T cells was illustrated by a change in their signature transcriptional profile and the acquisition of potent regulatory capacity. Comparisons of the transcriptional profiles of pre- and postconversion TH17 cells also revealed a role for canonical TGF-β signalling and consequently for the aryl hydrocarbon receptor (AhR) in conversion. Thus, TH17 cells transdifferentiate into regulatory cells, and contribute to the resolution of inflammation. Our data suggest that TH17 cell instability and plasticity is a therapeutic opportunity for inflammatory diseases.

Silicon nanowires were synthesized, in a controlled manner, for their practical integration into devices. Gold colloids were used for nanowire synthesis by the vapor-liquid-solid growth mechanism. Using SiCl4 as the precursor gas in a chemical vapor deposition system, nanowire arrays were grown vertically aligned with respect to the substrate. By manipulating the colloid deposition on the substrate, highly controlled growth of aligned silicon nanowires was achieved. Nanowire arrays were synthesized with narrow size distributions dictated by the seeding colloids and with average diameters down to 39 nm. The density of wire growth was successfully varied from approximately 0.1-1.8 wires/microm2. Patterned deposition of the colloids led to confinement of the vertical nanowire growth to selected regions. In addition, Si nanowires were grown directly into microchannels to demonstrate the flexibility of the deposition technique. By controlling various aspects of nanowire growth, these methods will enable their efficient and economical incorporation into devices.

Silicon nanowires have received considerable attention as transistor components because they represent a facile route toward sub-100-nm single-crystalline Si features. Herein we demonstrate the direct vertical integration of Si nanowire arrays into surrounding gate field effect transistors without the need for postgrowth nanowire assembly processes. The device fabrication allows Si nanowire channel diameters to be readily reduced to the 5-nm regime. These first-generation vertically integrated nanowire field effect transistors (VINFETs) exhibit electronic properties that are comparable to other horizontal nanowire field effect transistors (FETs) and may, with further optimization, compete with advanced solid-state nanoelectronic devices.

Highlights Deterministic barcoding in tissue enables NGS-based spatial multi-omics mapping. DBiT-seq identified spatial patterning of major tissue types in mouse embryos. DBiT-seq revealed fine features such as retinal pigmented epithelium and microvascular endothelium at the cellular level. Direct integration with scRNA-seq data allows for rapid cell type identification.

Blood comprises the largest version of the human proteome1. Changes of plasma protein profiles can reflect physiological or pathological conditions associated with many human diseases, making blood the most important fluid for clinical diagnostics2-4. Nevertheless, only a handful of plasma proteins are utilized in routine clinical tests. This is due to a host of reasons, including the intrinsic complexity of the plasma proteome1, the heterogeneity of human diseases and the fast kinetics associated with protein degradation in sampled blood5. Simple technologies that can sensitively sample large numbers of proteins over broad concentration ranges, from small amounts of blood, and within minutes of sample collection, would assist in solving these problems. Herein, we report on an integrated microfluidic system, called the Integrated Blood Barcode Chip (IBBC). It enables on-chip blood separation and the rapid measurement of a panel of plasma proteins from small quantities of blood samples including a fingerprick of whole blood. This platform holds potential for inexpensive, non-invasive, and informative clinical diagnoses, particularly, for point-of-care.

Cellular immunity has an inherent high level of functional heterogeneity. Capturing the full spectrum of these functions requires analysis of large numbers of effector molecules from single cells. We report a microfluidic platform designed for highly multiplexed (more than ten proteins), reliable, sample-efficient (~1 × 104 cells) and quantitative measurements of secreted proteins from single cells. We validated the platform by assessment of multiple inflammatory cytokines from lipopolysaccharide (LPS)-stimulated human macrophages and comparison to standard immunotechnologies. We applied the platform toward the ex vivo quantification of T cell polyfunctional diversity via the simultaneous measurement of a dozen effector molecules secreted from tumor antigen–specific cytotoxic T lymphocytes (CTLs) that were actively responding to tumor and compared against a cohort of healthy donor controls. We observed profound, yet focused, functional heterogeneity in active tumor antigen–specific CTLs, with the major functional phenotypes quantitatively identified. The platform represents a new and informative tool for immune monitoring and clinical assessment.