Reliably reconnecting severed tissues is a critical part of any invasive medical procedure. Although, sutures and staples are ideal choices due to their effectiveness, adhesives hold great promise as alternatives for bonding tissues. Although many bio-adhesives are commercially available, no product yet combines all desirable properties such as consistent adhesion to wet surfaces, mechanical durability, molecular-level customizability and biocompatibility. UC Berkeley research have developed a recombinant protein-based adhesive by chemically functionalizing elastin-like polypeptides (ELPs).  These ELPs form stable and flexible hydrogels de-swell in aqueous conditions. An additional strength of using recombinant proteins is exhibited by significantly enhancing cell binding to this ELP by a simple modular addition of an engineered protein with ‘RGD’ peptides. 

Several chemical, physical, and biological techniques have been used for delivering macromolecules into living cells. Delivery of biomolecules into living cells is essential for biomedical research and drug development as well as genome editing. However, conventional methods of delivery of biomolecules such as viral vectors, cell penetrating peptides, cationic lipids, positive charged polymers, bulk electroporation, and microinjection pose several challenges. Such challenges include safety concerns, toxicity, damage to the cells, limited loading capacity, low delivery efficiencies, low cell viabilities, low cell throughput, high cellular perturbation, and high costs.  Thus, there is a need for delivery devices and methods that allow for permeabilization of the cell membrane to facilitate delivery of biomolecules into cells.   UC Berkeley researchers have developed a universal delivery electroporation system that makes cell transfection very simple for all of types of cells. The technology can be used to replace conventional cellular delivery methods such as cationic lipid, positive charged polymer and bulk electroporation as well as microinjection.  The system can deliver biomolecules (e.g., DNA, RNA, proteins, nucleic acid-protein complexes (e.g., RNPs)) or other reagents into all cell types, including T-cells, which cannot be efficiently transfected with conventional approaches.  

Class 2 CRISPR-Cas systems are streamlined versions in which a single Cas protein (an effector protein, e.g., a type V Cas effector protein such as Cpf1) bound to RNA is responsible for binding to and cleavage of a targeted sequence. The programmable nature of these minimal systems has facilitated their use as a versatile technology that continues to revolutionize the field of genome manipulation.    Cas12 is an RNA-guided protein that binds and cuts any matching DNA sequence. Binding of the Cas12-CRISPR RNA (crRNA) complex to a matching single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) molecule activates the protein to non-specifically degrade any ssDNA in trans. Cas12a-dependent target binding can be coupled to a reporter molecule to provide a direct readout for DNA detection within a sample.  UC Berkeley researchers have developed compositions, systems, and kits having labeled single stranded reporter DNA molecules that provide a sensitive readout for detection of a target DNA. 

Sanger sequencing has remained a dominant DNA sequencing methodology for molecular biology research and development for many years.  The main commercially available DNA polymerase developed for Sanger sequencing has a slow extension speed and has difficulties sequencing secondary structures such as GC rich regions, hairpins, mono- and poly-nucleotide repeats.  While specialized plastics and reductions in reaction volumes to improve Sanger sequencing reaction times, any gains in sequencing assay performance (e.g., sequencing time or throughput) are offset by increased costs associated with a terminator reagent.  During the last two decades, further refinement and advancement of suitable DNA polymerases to improve polymerization speeds during Sanger sequencing have been limited.  Thus, there remains a need for improved DNA polymerases suitable for Sanger sequencing that possess enhanced elongation speeds, and the ability to sequence through secondary structures present in DNA templates.    A UC Berkeley researchers has discovered compositions and methods for preparing and using Taq DNA polymerases with improved Sanger sequencing elongation sequencing rates as compared to commercially available Sanger sequencing reagents.  

Single-cell analysis offers powerful capabilities of identification of rare sub-populations of cells, understanding heterogeneity of cancerous tumors, and tracking cell differentiation and reprogramming. Despite great potentials for uncovering new biological systems and targeting diseases with precision medicine, single-cell approaches are composed of complex device processes that can cause bias in measurement.  In deep sequencing, technical variation in single cell expression data occurs during capture and pre-amplification steps. Similarly, in single-cell protein assays, technical variability can obscure functionally relevant variance.    To better control protein measurement quality in single-cell assays, researchers at the University of California, Berkeley developed a novel method to loading and release protein standard. This method utilizes the surface of modified and functionalized microparticles as vehicles to capture target proteins with desired concentrations. Chelation-assisted click chemistry is applied to demonstrate that protein standards with different molecular masses can be loaded and bounded in a single-cell protein assay. Microparticles are introduced into single-cell devices by either passive gravity, magnetic attraction, or other physicochemical forces. These protein standards from microparticles provide a reference to measure protein mass sizes from individual cells and a quality control for any biases in device fabrication, cell lysis, protein solubility, protein capture, and protein readouts (i.e. antibody probing).   

96 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Bacteria and archaea possess adaptive immune systems that rely on small RNAs for defense against invasive genetic elements. CRISPR (clustered regularly interspaced short palindromic repeats) genomic loci are transcribed as long precursor RNAs, which must be enzymatically cleaved to generate mature CRISPR-derived RNAs (crRNAs) that serve as guides for foreign nucleic acid targeting and degradation. This processing occurs within the repetitive sequence and is catalyzed by a dedicated CRISPR-associated (Cas) family member in many CRISPR systems.  Endoribonucleases that process CRISPR transcripts are bacterial or archaeal enzymes capable of catalyzing sequence- and structure- specific cleavage of a single- stranded RNA. These enzymes cleave a specific phosphodiester bond within a specific RNA sequence.  UC Berkeley researchers discovered variant Cas endoribonucleases, nucleic acids encoding the variant Cas endoribonucleases, and host cells genetically modified with the nucleic acids that can be used, potentially in conjunction with Cas9, to detect a specific sequence in a target polyribonucleotide and of regulating production of a target RNA in a eukaryotic cell.  For example, it was found that the variant Cas endoribonuclease has an amino acid substitution at a histidine residue such that is is enzymatically inactive in the absence of imidazole and is activatable in the presence of imidazole.  

Natural gas, composed primarily of methane, has many potential uses as a cleaner and more renewable source of energy than other fossil fuels. However, about 20% of US natural gas reserves contain levels of N2 that are too high for pipeline processing. Using natural gas from renewable sources also encounters this problem. Furthermore, in processing steps to create high-purity methane from its various sources, the removal of N2 remains a significant energetic cost. This separation is typically performed through cryogenic distillation, and improvements in energy efficiency of this separation are necessary to utilize the many available sources of methane. Switching to membrane or adsorbent-based technologies could potentially alleviate this challenge. Size selective molecular sieves and membranes have demonstrated some ability for separating N2 from CH4, but face problems with scalability and selectivity; and current adsorbents need significant improvements in selectivity and capacity for N2 to be commercially viable.  To address this situation, researchers at UC Berkeley have developed a new adsorbent V2Cl2(btdd) with exceptional affinity for nitrogen, such that early experiments already demonstrate a N2/CH4 selectivity of over 10x greater than any reported material. The Berkeley material is a permanently porous vanadium(II)-containing metal-organic framework (MOF). It represents the first example of a MOF with five-coordinate vanadium(II) centers as the primary metal node. The electronic properties of these five-coordinate V(II) centers make this MOF uniquely reactive towards relatively inert and weak electron acceptors, such as nitrogen, creating a stronger M–N2 interaction than any known MOF. Additionally, the high-density of V(II) centers translates to a high gas uptake capacity, qualifying this material as a promising N2/CH4 selective adsorbant. Key performance parameters can be tuned as the building blocks are synthetically modifiable.

Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Class 2 CRISPR–Cas systems (e.g., type V CRISPR/Cas systems such as Cas12 family systems) are characterized by effector modules that include a single effector protein. For example, in a type V CRISPR/Cas system, the effector protein - a CRISPR/Cas endonuclease (e.g., a Cas12a protein) - interacts with (binds to) a corresponding guide RNA (e.g., a Cas12a guide RNA) to form a ribonucleoprotein (RNP) complex that is targeted to a particular site in a target nucleic acid via base pairing between the guide RNA and a target sequence within the target nucleic acid molecule.  Thus, like CRISPR-Cas9, Cas12 has been harnessed for genome editing based on its ability to generate targeted, double-stranded DNA (dsDNA) breaks.   UC Berkeley researchers have discovered that RNA-guided DNA binding unleashes indiscriminate single-stranded DNA (ssDNA) cleavage activity by Cas12a that completely degrades ssDNA molecules. The researchers found that target-activated, non-specific ssDNase cleavage is also a property of other type V CRISPR-Cas12 enzymes. By combining Cas12a ssDNase activation with isothermal amplification, the researchers were able to achieve attomolar sensitivity for DNA detection.  For example, rapid and specific detection of human papillomavirus in patient samples was achieved using these methods and compositions.   

Additive manufacturing fabrication methods are proliferating rapidly, with photopolymer-based approaches comprising some of the most prominent methods. These stereolithographic techniques provide a useful balance of resolution, build speed, process control, and capital cost (system metrics that typically must be traded off one against another). Resolving the speed limitations, surface roughness (stair-step artifacts), and requirements for support structures would provide the next major steps forward in the progress of these technologies.To address this potential, researchers at UC Berkeley have developed a system and method that accomplishes volumetric fabrication by applying computed tomography techniques in reverse, fabricating structures by exposing a photopolymer resin volume from multiple angles, updating the light field at each angle. The necessary light fields are spatially and/or temporally multiplexed, such that their summed energy dose in a target resin volume crosslinks the resin into a user-defined geometry. These light-fields may be static or dynamic and may be generated by a spatial light modulator that controls either the phase or the amplitude of a light field (or both) to provide the necessary intensity distribution.

Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman",serif; mso-fareast-language:JA;} Van der Waals crystals are a class of materials composed of stacked layers. Individual layers are single- or few-atoms thick and exhibit unique mechanical, electrical, and optical properties, and are thus expected to see widespread adoption in devices across a range of fields such as optical, electronic, sensing, and biomedical devices.  Graphene and transition metal dichalcogenides offer desirable properties as few-layer or monolayer film. Accessing the monolayer form in a repeatable fashion, as part of a predictable and high-yield manufacturing process is critical to realizing the many potential applications of two-dimensional materials at scale. In order to fabricate devices made from few- or monolayer materials, layer(s) of material of specified size and shape, arranged in a pre-determined pattern, must be deposited on a desired substrate and conventional transfer methods include pressure-sensitive adhesives and other viscoelastic polymers and require applied pressure to adhere to their target which can cause out-of-plane deformations and problems with isolating and transferring the patterned few- or monolayer material. Deep etching has similar drawbacks.   UC Berkeley researchers have discovered methods and compositions that enable the transfer medium to adhere strictly to patterned regions, allowing the transfer to remove only patterned material and leave behind unpatterned bulk. This method involves the creation of an intermediate layer between the source material and the transfer medium. Because this layer must strictly cover patterned material, it serves as an etch mask for isolating few-layer material in the desired pattern. Any material which is microns-thick, patternable at the desired lateral pattern scale (likely micron-scale), and subsequently removable would make a suitable intermediate layer. 

96 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} The CRISPR-Cas system is now understood to confer bacteria and archaea with acquired immunity against phage and viruses. CRISPR-Cas systems consist of Cas proteins, which are involved in acquisition, targeting and cleavage of foreign DNA or RNA, and a CRISPR array, which includes direct repeats flanking short spacer sequences that guide Cas proteins to their targets. The programmable nature of these systems has facilitated their use as a versatile technology that is revolutionizing the field of genome manipulation. There is a need in the art for additional CRISPR-Cas systems with improved cleavage and manipulation under a variety of conditions and ones that are particularly thermostable under those conditions.     UC researchers discovered a new type of RNA-guided endonuclease (GeoCas9) and variants of GeoCas9.  GeoCas9 was found to be stable and enzymatically active in a temperature range of from 15°C to 75°C and has extended lifetime in human plasma.  With evidence that GeoCas9 maintains cleavage activity at mesophilic temperatures, the ability of GeoCas9 to edit mammalian genomes was then assessed.  The researchers found that when comparing the editing efficiency for both GeoCas9 and SpyCas9, similar editing efficiencies by both proteins were observed, demonstrating that GeoCas9 is an effective alternative to SpyCas9 for genome editing in mammalian cells.  Similar to CRISPR-Cas9, GeoCas9 enzymes are expected to have a wide variety of applications in genome editing and nucleic acid manipulation.   

96 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Current methods of biomolecule delivery to mature plants are limited due to the presence of plant cell wall, and are additionally hampered by low transfection efficiency, high toxicity of the transfection material, and host range limitation. For this reason, transfection is often limited to protoplast cultures where the cell wall is removed, and not to the mature whole plant.  Unfortunately, protoplasts are not able to regenerate into fertile plants, causing these methods to have low practical applicability. Researchers at the University of California have developed a method for delivery of genetic materials into mature plant cells within a fully-developed mature plant leaf, that is species-independent. This method utilizes a nano-sized delivery vehicle for targeted and passive transport of biomolecules into mature plants of any plant species. The delivery method is inexpensive, easy, and robust, and can transfer biomolecules into all phenotypes of any plant species with high efficiency and low toxicity.

96 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} The biological properties of trifluoromethyl compounds (e.g, CF3) have led to their ubiquity in pharmaceuticals, yet their chemical properties have made their preparation a substantial challenge, necessitating innovative chemical solutions.  For example, strong, non-interacting C-F bonds lend metabolic stability while simultaneously limiting the ability of chemical transformations to forge the relevant linkages and install the CF3 unit.  When these same synthetic considerations are extended toward the synthesis of trifluoromethylated positron emission tomography (PET) tracers, the situation becomes more complex.   UC Berkeley researchers discovered an unusual alternative mechanism, in which borane abstracts fluoride from the CF3 group in a gold complex. The activated CF2 fragment can then bond to a wide variety of other carbon substituents added to the same gold center. Return of the fluoride liberates a trifluoromethylated compound from the metal. This mechanism would be useful for the introduction of radioactive fluoride substituents for potential tracers to be used for positron emission tomography applications.

96 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Endocrine disrupting compounds are found in increasing amounts in our environment, originating from pesticides, plasticizers, and pharmaceuticals, among other sources. These compounds have been implicated in diseases such as obesity, diabetes, and cancer. The list of chemicals that disrupt normal hormone function is growing at an alarming rate, making it crucially important to find sources of contamination and identify new compounds that display this ability. However, there is currently no broad-spectrum, rapid test for these compounds, as they are difficult to monitor because of their high potency and chemical dissimilarity.   To address this, UC Berkeley researchers have developed a new detection system and method for the sensitive detection of trace compounds using electrochemical methods.  This platform is both fast and portable, and it requires no specialized skills to perform. This system enables both the detection of many detrimental compounds and signal amplification from impedance measurements due to the binding of bacteria to a modified electrode. The researchers were able to test the system finding sub-ppb levels of estradiol and ppm levels of bisphenol A in complex solutions. This approach should be broadly applicable to the detection of chemically diverse classes of compounds that bind to a single receptor.  

Neurotransmitters play a central role in complex neural networks by serving as chemical units of neuronal communication.  Quantitative optical methods for the detection of changes in neurotransmitter levels has the potential to profoundly increase our understanding of how the brain works. Therapeutic drugs that target neurotransmitter release are used ubiquitously to treat a vast array of brain and behavioral disorders.  For example, new methods in this sphere could provide a new platform by which to validate the function of drugs that alter modulatory neurotransmission, or to screen antipsychotic and antidepressant drugs.  However, currently in neuroscience, few optical methods exist that can detect neurotransmitters with high spatial and temporal resolution in vitro or in vivo.  Brain tissue also readily scatters visible wavelengths of light currently used to perform biological imaging, and neuronal tissue and has an abundance of biomolecules that are chemically or structurally similar and therefore hard to specifically distinguish.  Furthermore, neurotransmission relevant processes occur at challenging spatial  and temporal scales.    UC Berkeley investigators have developed polymer-functionalized carbon nanotubes for in vitro and in vivo quantification of extracellular modulatory neurotransmitter levels using optical detectors. The method uses the fluorescent optical properties of polymer-functionalized carbon nanotubes to selectively report changes in concentration of specific neurotransmitters. The scheme is novel in that the detection method applies to wide variety of specific neurotransmitters, it is an optical method and therefore gives greater spatial information, and enables the potential for imaging of one or more neurotransmitters. The optical method also produces less damage to the surrounding tissue than methods that implant electrodes or cells and allows high resolution localization with other methods of optical investigation. The invention takes advantage of favorable fluorescence properties of carbon nanotubes, such as carbon nanotube emission in the near infrared and infinite fluorescence lifetime.  The near infrared emission scatters less than shorter wavelengths, enabling greater signal recovery from deeper tissue, and allows greater compatibility with other techniques. The optical properties also enable long term potentially even chronic use. 

96 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Self-assembling protein nanomaterials derived from viruses have properties that make them useful for applications in drug delivery, disease imaging and diagnostics. These properties include uniform sizes and shapes, biodegradability, and multiple sets of functional handles for chemical manipulation. Intact virus nanoparticles have been functionalized for applications in drug delivery in vivo, however, the injection of replication-competent viruses into subjects have limited their clinical appeal. The development of spherical and rod-shaped virus nanoparticles has in both cases resulted in differential tumor accumulation, demonstrating the need to further expand the shape library of protein nanomaterials. However, expressing non-spherical virus-based protein nanomaterials without the genetic material that functions as a backbone to the assembly architecture can lead to significant challenges including poly-diversity in size and shape, and change in assembly behavior in response to different conditions such as pH and ionic strength.   UC Berkeley researchers have developed a self-assembling nanoscale disk derived from a mutant of a recombinantly expressed viral coat protein. The disks display highly stable double-disk assembly states. The researchers functionalized the disks with the chemotherapy drug doxorubicin (DOX) and further modified the disks for improved solubility.  The functionalized disks displayed cytotoxic properties similar to those of DOX alone when incubated with U87MG glioblastoma cells, but the unmodified disks did not cause any cytotoxicity.

Flow reactors are a useful method for Olefin epoxidation reactions, which are highly exothermic reactions.  Organic hydroperoxide and olefin conversion levels to epoxide are low at the entrance of the reactors and improve at the tail end of the reactor.  At the tail end of the reactor, there is excess alcohol coproduct and hydroperoxide in addition to epoxide.  Both Solid and liquid catalysts are used to improve conversion levels at all stages in the reactors.  The catalysts to date are efficient at the entrance of the reactor, but lose efficiency at the tail end of the reactor where epoxide is to be produced and separated.   Researchers at UC Berkeley have developed a crystalline solid catalyst for olefin epoxidation which is highly selective for epoxide production at the extreme conditions of high temperature and organic-hydroperoxide conversion at the tail end of the olefin-epoxidation reactor.  The catalyst is white crystalline solid of titanium and is based on a layered zeolite precursor.  The researchers have further developed methods of using multiple catalysts in a single reactor, where the developed catalyst is used as the catalyst at the tail end of the reactor, in the form of a packed bed, while one or more other catalyst(s) are used at the entrance of the reactor.

Single-crystal x-ray diffraction is a powerful technique for the definitive identification of chemical structures.  Although most molecules and molecular complexes can be crystallized, often enthalpic and entropic factors introduce orientational disorder that prevent determination of a high-resolution structure.  Several strategies based on the inclusion of guests in a host framework that helps maintain molecular orientation have been used to overcome this challenge.  However, most of these methods rely primarily on weak interactions to induce crystalline order of the included molecules. Researchers at UC Berkeley have developed a strategy for crystallization of molecules within the pores of chiral metal-organic frameworks (MOFs) using coordinative bonding, which includes covalent and ionic bonds, and/or using chirality.  

96 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} GGDEF domain-containing enzymes are diguanylate cyclases that produce cyclic di-GMP (cdiG), a second messenger that modulates the key bacterial lifestyle transition from a motile to sessile biofilm-forming state. The ubiquity of genes encoding GGDEF proteins in bacterial genomes has established the dominance of cdiG signaling in bacteria. A subfamily of GGDEF enzymes synthesizes the asymmetric signaling molecule cyclic AMP-GMP. Hybrid CDN-producing and promiscuous substrate-binding (Hypr) GGDEF enzymes are widely distributed and found in other deltaproteobacteria and have roles that include regulation of cAG signaling.  GGDEF enzymes that produce cyclic dinucleotides are especially of interest.    UC Berkeley researcher have developed a new method of preparing and using cyclic dinucleotides (CDNs) by contacting a CDN producing-enzyme (e.g., a GGDEF enzyme) with a precursor of a CDN under conditions sufficient to convert the precursor into a CDN. This method produces a variety of non-naturally occurring, asymmetric and symmetric CDNs and can be performed in vitro or in a genetically modified host cell. Also provided are CDN compositions that find use in a variety of applications such as modulating an immune response in an individual.  

96 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} The ∼10% optical contrast of graphene on specialized substrates like oxide-capped silicon substrates, together with the high-throughput and noninvasive features of optical microscopy, have greatly facilitated the use and research of graphene research for the past decade.  However, substantially lower contrast is obtained on transparent substrates. Visualization of nanoscale defects in graphene, e.g., voids, cracks, wrinkles, and multilayers, formed during either growth or subsequent transfer and fabrication steps, represents yet another level of challenge for most device substrates.     UC Berkeley researchers have developed a facile, label-free optical microscopy method to directly visualize graphene on transparent inorganic and polymer substrates at 30−40% image contrast per graphene layer.  Their noninvasive approach overcomes typical challenges associated with transparent substrates, including insulating and rough surfaces, enables unambiguous identification of local graphene layer numbers and reveals nanoscale structures and defects with outstanding contrast and throughput. We thus demonstrate in situ monitoring of nanoscale defects in graphene, including the generation of nano-cracks under uniaxial strain, at up to 4× video rate.  

Flexible electrostatic actuators are well designed for a range of commercial applications, from small micro-mechanical robotics to large vector displays or sound wall systems. Electrostatic actuation provides efficient, low-power, fast-response driving and control of movable nano-, micro-, and macro-structures. While commercially available electrostatic actuators have the requisite high levels of mechanical energy / force for some applications, their energy requirements are typically orders of magnitude higher than what is needed in large-area, low-power applications. Moreover, conventional approaches to these types of electrostatic actuators have limited design geometries and are prone to reliability issues like electrical shorts. To address these problems, researchers at the University of California, Berkeley, have experimented with planar electrostatic actuators using novel printing and electrode patterning and engineering techniques. The team has demonstrated a repulsive-force electrostatic actuator device (100 mm x 60 mm achieved) with extremely high field strength and high voltage operation and without insulator coatings or air breakdown.

Bacterial adaptive immune systems employ CRISPRs and CRISPR-associated (Cas) proteins for RNA-guided nucleic acid cleavage. Although generally targeted to DNA substrates, the Type VI CRISPR system directs interference complexes against single-stranded RNA substrates and in Type VI CRISPR systems, the single-subunit Cas13a/C2c2 protein functions as an RNA-guided RNA endonuclease.   UC Berkeley researchers have discovered that the CRISPR-Cas13a/C2c2 has two distinct RNase activities that enable both single stranded target RNA detection and multiplexed guide-RNA processing.  These dual RNase functions were found to be chemically and mechanistically different from each other and from the CRISPR RNA processing behavior of the evolutionarily unrelated CRISPR enzyme Cpf1.  Methods for detecting the single stranded target RNA were also discovered using a Cas13a/C2c2 guide RNA and a Cas13a/C2c2 protein in a sample have a plurality of RNAs as well as methods of cleaving a precursor Cas13a/C2c2 guide RNA into two or more Cas13a/C2c2 guide RNAs.  

The development of fluorescent indicators for sensing membrane potential can be a challenge.  Traditional methods to measure membrane potential rely on invasive electrodes, however, voltage imaging with fluorescent probes (VF) is an attractive solution because voltage imaging circumvents problems of low- throughput, low spatial resolution, and high invasiveness. Previously reported VF probes/dyes have proven useful in a number of imaging contexts. However, the design scheme for VF dyes remains elusive, due in part to our incomplete understanding of the biophysical properties influencing voltage sensitivity in our VoltageFluor scaffolds.   UC Berkeley researchers have discovered new VF dyes, which are a small molecule platform for voltage imaging that operates via a photoinduced electron transfer (PeT) quenching mechanism to directly image transmembrane voltage changes.   The dyes further our understanding of the roles that membrane voltage plays, not only in excitable cells, such as neurons and cardiomyocytes, but also in non-excitable cells in the rest of the body.

Metal–organic frameworks (MOFs) are an important class of materials with high internal surface areas and tunable pore environments that make them of interest for a wide variety of potential applications, including gas adsorption and drug delivery. One of the most ubiquitous MOF materials is of the type M2(dobdc) (2,5-dioxido-1,4-benzenedicarboxylate), sometimes referred to as M-MOF-74. The pores of these frameworks can be expanded while preserving the parent framework structure by using ligands and other analogues with multiple phenylene groups.   With an interest in exploring new ligands for expanded MOF-74 architectures, UC Berkeley researschers created a new family of expanded MOF-74 materials using the anti-inflammatory olsalazine acid as a ligand to form M2(olz), where M = Mg, Fe, Co, Ni, and Zn. Upon activation, these materials exhibit the highest Langmuir surface areas among bioactive frameworks. The M2(olz) frameworks contain pore apertures of approximately 27 Å, corresponding to the mesoporous range (≥20 Å). Strong H2 adsorption was observed by gas adsorption studies and in situ infrared spectroscopy, confirming the presence of open metal sites for all but the Zn analogue. The Mg2(olz) framework, which disassembles under physiological conditions to release olsalazine, represents an unprecedented level of loading in a bioactive metal–organic framework of 86 wt % drug. In addition to delivery of olsalazine, the large pores of Mg2(olz) were used to encapsulate a second drug, illustrating the potential of this platform to deliver multiple therapeutic components.  

Nanostructured metal oxide materials have generated much interest for sensing applications due to their high surface area, low thermal mass, and superior performance.  However, stable and reproducible integration of these materials into a functional sensor is difficult. Vacuum deposition techniques such as sputtering or evaporation do not offer substantial sensing performance improvement. Sacrificial templating steps have been suggested, but the manufacturing complexity and cost are not suitable for high volume production. There remains a need for a simple, effective method to prepare nanostructured metal oxide films for low power, miniaturized gas sensors with high sensitivity.   Researchers at UC Berkeley have developed a novel method for creating highly porous, nanostructured metal oxide film in a controlled location from a liquid precursor using a localized heat source. This method eliminates processing steps, such as the need to separately synthesize nanomaterials and suspend them into a stable ink for deposition. The localized heat source acts to both evaporate the solvent and thermally decompose the precursor into a highly porous film of nanocrystalline metal oxide, as well as to define the location of the formed film. The utility of this method has been demonstrated for the formation of a tin oxide gas sensor with superior performance, including high sensitivity and fast response and recovery time for carbon monoxide gas. However, the method could be useful for other applications that require localized formation of a porous film of nanocrystalline metal oxide.