High-density microfluidic chips contain plumbing networks with thousands of micromechanical valves and hundreds of individually addressable chambers. These fluidic devices are analogous to electronic integrated circuits fabricated using large scale integration (LSI). A component of these networks is the fluidic multiplexor, which is a combinatorial array of binary valve patterns that exponentially increases the processing power of a network by allowing complex fluid manipulations with a minimal number of inputs. These integrated microfluidic networks can be used to construct a variety of highly complex microfluidic devices, for example the microfluidic analog of a comparator array, and a microfluidic memory storage device resembling electronic random access memories.

https://science.sciencemag.org/content/sci/298/5593/580.full.pdf

Microfluidic large scale integration

To achieve a sustainable society with an energy mix primarily based on solar energy, we need methods of storing energy from sunlight as chemical fuels. Photoelectrochemical (PEC) devices offer the promise of solar fuel production through artificial photosynthesis. Although the idea of a carbon-neutral energy economy powered by such ‘artificial leaves’ is intriguing, viable PEC energy conversion on a global scale requires the development of devices that are highly efficient, stable and simple in design. In this Review, recently developed semiconductor materials for the direct conversion of light into fuels are scrutinized with respect to their atomic constitution, electronic structure and potential for practical performance as photoelectrodes in PEC cells. The processes of light absorption, charge separation and transport, and suitable energetics for energy conversion in PEC devices are emphasized. Both the advantageous and unfavourable aspects of multinary oxides, oxynitrides, chalcogenides, classic semiconductors and carbon-based semiconductors are critically considered on the basis of their experimentally demonstrated performance and predicted properties. Photoelectrochemical (PEC) devices offer the promise of efficient artificial photosynthesis. In this Review, recently developed light-harvesting materials for PEC application are scrutinized with respect to their atomic constitution, electronic structure and potential for practical performance in PEC cells.

Semiconducting materials for photoelectrochemical energy conversion

The conversion of sunlight into fuels and chemicals is an attractive prospect for the storage of renewable energy, and photoelectrocatalytic technologies represent a pathway by which solar fuels might be realized. However, there are numerous scientific challenges in developing these technologies. These include finding suitable materials for the absorption of incident photons, developing more efficient catalysts for both water splitting and the production of fuels, and understanding how interfaces between catalysts, photoabsorbers and electrolytes can be designed to minimize losses and resist degradation. In this Review, we highlight recent milestones in these areas and some key scientific challenges remaining between the current state of the art and a technology that can effectively convert sunlight into fuels and chemicals.

Materials for solar fuels and chemicals

Over the past decade, RNA sequencing (RNA-seq) has become an indispensable tool for transcriptome-wide analysis of differential gene expression and differential splicing of mRNAs. However, as next-generation sequencing technologies have developed, so too has RNA-seq. Now, RNA-seq methods are available for studying many different aspects of RNA biology, including single-cell gene expression, translation (the translatome) and RNA structure (the structurome). Exciting new applications are being explored, such as spatial transcriptomics (spatialomics). Together with new long-read and direct RNA-seq technologies and better computational tools for data analysis, innovations in RNA-seq are contributing to a fuller understanding of RNA biology, from questions such as when and where transcription occurs to the folding and intermolecular interactions that govern RNA function.

RNA sequencing: the teenage years

A diverse catalog of long noncoding RNAs (lncRNAs), which lack protein-coding potential, are transcribed from the mammalian genome. They are emerging as important regulators in gene expression networks by controlling nuclear architecture and transcription in the nucleus and by modulating mRNA stability, translation and post-translational modifications in the cytoplasm. In this Review, we highlight recent progress in cellular functions of lncRNAs at the molecular level in mammalian cells.

Cellular functions of long noncoding RNAs.

Imaging the transcriptome in situ with high accuracy has been a major challenge in single-cell biology, which is particularly hindered by the limits of optical resolution and the density of transcripts in single cells1-5. Here we demonstrate an evolution of sequential fluorescence in situ hybridization (seqFISH+). We show that seqFISH+ can image mRNAs for 10,000 genes in single cells-with high accuracy and sub-diffraction-limit resolution-in the cortex, subventricular zone and olfactory bulb of mouse brain, using a standard confocal microscope. The transcriptome-level profiling of seqFISH+ allows unbiased identification of cell classes and their spatial organization in tissues. In addition, seqFISH+ reveals subcellular mRNA localization patterns in cells and ligand-receptor pairs across neighbouring cells. This technology demonstrates the ability to generate spatial cell atlases and to perform discovery-driven studies of biological processes in situ.

/pdf/transcriptome-scale-super-resolved-imaging-in-tissues-by-rna-dsgk0ubydg.pdf

Transcriptome-scale super-resolved imaging in tissues by RNA seqFISH

Dynamics and Spatial Genomics of the Nascent Transcriptome by Intron seqFISH

Microfluidic devices for splitting an established fluidic flow through a microfluidic channel among multiple downstream microfluidic channels include a plurality of elevated flow resistance regions to promote precise and predictable splitting. Each elevated resistance region imparts a flow resistance that is substantially greater than the characteristic resistance to established flow of its associated downstream channel. Elevated flow resistance regions may include one or more porous materials and/or alterations to the channel geometry of at least a portion of a downstream channel.

Flow control in multi-stream microfluidic devices

Modular microfluidic systems includes a plurality of microfluidic modules, each capable of performing fluidic operations including, but not limited to, filtering, splitting, regulating pressure, mixing, metering, reacting, diverting, heating, cooling, and condensing are provided. The microfluidic modules are polymeric, stencil-based structures adapted to be coupled in sequence for performing biological or chemical synthesis, including, but not limited to, chemical and biological syntheses of organic, polymer, inorganic, oligonucleotide, peptide, protein, bacteria, and enzymatic products.

Microfluidic analytical devices and methods

A microfluidic reactor for performing chemical and biological synthesis reactions, including chemical and biological syntheses of organic, polymer, inorganic, oligonucleotide, peptide, protein, bacteria, and enzymatic products is provided. Two fluids are input into the device, mixed in a mixing region and provided to a long, composite reaction channel. Fluids flowing through the reaction channel may be diverted at a diversion region into a sample channel. Fluids in the sample channel may be mixed at a second region, with additional reagents.

Christoph D. Karp

Papers

Transcriptome-scale super-resolved imaging in tissues by RNA seqFISH

Dynamics and Spatial Genomics of the Nascent Transcriptome by Intron seqFISH

Flow control in multi-stream microfluidic devices

Microfluidic analytical devices and methods

Microfluidic synthesis devices and methods