Authors: Lu Wei, Zhixing Chen, Lixue Shi...

The ability to visualize directly a large number of distinct molecular species inside cells is increasingly essential for understanding complex systems and processes. Even though existing methods have successfully been used to explore structure-function relationships in nervous systems, to profile RNA in situ, to reveal the heterogeneity of tumour microenvironments and to study dynamic macromolecular assembly, it remains challenging to image many species with high selectivity and sensitivity under biological conditions. For instance, fluorescence microscopy faces a 'colour barrier', owing to the intrinsically broad (about 1,500 inverse centimetres) and featureless nature of fluorescence spectra that limits the number of resolvable colours to two to five (or seven to nine if using complicated instrumentation and analysis). Spontaneous Raman microscopy probes vibrational transitions with much narrower resonances (peak width of about 10 inverse centimetres) and so does not suffer from this problem, but weak signals make many bio-imaging applications impossible. Although surface-enhanced Raman scattering offers high sensitivity and multiplicity, it cannot be readily used to image specific molecular targets quantitatively inside live cells. Here we use stimulated Raman scattering under electronic pre-resonance conditions to image target molecules inside living cells with very high vibrational selectivity and sensitivity (down to 250 nanomolar with a time constant of 1 millisecond). We create a palette of triple-bond-conjugated near-infrared dyes that each displays a single peak in the cell-silent Raman spectral window; when combined with available fluorescent probes, this palette provides 24 resolvable colours, with the potential for further expansion. Proof-of-principle experiments on neuronal co-cultures and brain tissues reveal cell-type-dependent heterogeneities in DNA and protein metabolism under physiological and pathological conditions, underscoring the potential of this 24-colour (super-multiplex) optical imaging approach for elucidating intricate interactions in complex biological systems.

Topics: Animals; Brain; Cell Line; Cell Survival; Coculture Techniques; Color; Coloring Agents; DNA; Electrons; Fluorescent Dyes; Humans; Infrared Rays; Mice; Molecular Imaging; Neurons; Organ Specificity; Proteins; Spectrum Analysis, Raman; Vibration

PubMed: 28424513
DOI: 10.1038/nature22051

Authors: Fei Zhang, Mingbo Pu, Ping Gao...

Optical metasurfaces enable novel ways to locally manipulate light's amplitude, phase, and polarization, underpinning a newly viable technology for applications, such as high-density optical storage, holography, and displays. Here, a high-security-level platform enabled by centimeter-scale plasmonic metasurfaces with full-color, high-purity, and enhanced-information-capacity properties is proposed. Multiple types of independent information can be embedded into a single metamark using full parameters of light, including amplitude, phase, and polarization. Under incoherent white light, the metamark appears as a polarization- and angle-encoded full-color image with flexibly controlled hue, saturation, and brightness, while switching to multiwavelength holograms under coherent laser illumination. More importantly, for actual applications, the extremely shallow functional layer makes such centimeter-scale plasmonic metamarks suitable for cost-effective mass production processes. Considering these superior performances of the presented multifunctional plasmonic metasurfaces, this work may find wide applications in anticounterfeiting, information security, high-density optical storage, and so forth.

PubMed: 32440472
DOI: 10.1002/advs.201903156

Authors: Jian Zhi, Siwei Zhao, Min Zhou...

A solid-state zinc-ion battery can fundamentally eliminate dendrite formation and hydrogen evolution on the zinc anode from aqueous systems. However, enabling fast zinc ion conduction in solid crystals is thought to be impossible. Here, we demonstrated a fluorine-doping approach to achieving fast Zn transport in mesoporous ZnSF. The substitutional doping of fluoride ion with sulfide substantially reduces Zn migration barrier in a crystalline phase, while mesopore channels with bounded dimethylformamide enable nondestructive Zn conduction along inner pore surface. This mesoporous conductor features a high room-temperature Zn conductivity (0.66 millisiemens per centimeter, compared with 0.01 to 1 millisiemens per centimeter for lithium solid-state electrolyte) with a superior cycling performance (89.5% capacity retention over 5000 cycles) in a solid zinc-ion battery and energy density (0.04 watt-hour per cubic centimeter) in a solid zinc-ion capacitor. The universality of this crystal engineering approach was also verified in other mesoporous zinc chalcogenide materials, which implies various types of potential Zn-conducting solid electrolytes.

PubMed: 36706189
DOI: 10.1126/sciadv.ade2217

Authors: Charlotte E G Hoskin, Vanessa Restrepo Schild, Javier Vinals...

Bioelectronic devices that are tetherless and soft are promising developments in medicine, robotics and chemical computing. Here, we describe bioinspired synthetic neurons, composed entirely of soft, flexible biomaterials, capable of rapid electrochemical signal transmission over centimetre distances. Like natural cells, our synthetic neurons release neurotransmitters from their terminals, which initiate downstream reactions. The components of the neurons are nanolitre aqueous droplets and hydrogel fibres, connected through lipid bilayers. Transmission is powered at these interfaces by light-driven proton pumps and mediated by ion-conducting protein pores. By bundling multiple neurons into a synthetic nerve, we have shown that distinct signals can propagate simultaneously along parallel axons, thereby transmitting spatiotemporal information. Synthetic nerves might play roles in next-generation implants, soft machines and computing devices.

Topics: Hydrogels; Lipid Bilayers; Neurons; Robotics; Water

PubMed: 35449216
DOI: 10.1038/s41557-022-00916-1

Review

Authors: Min Woo Lee, Hyo Keun Lim

Hepatocellular carcinomas (HCCs) frequently recur despite initial successful surgical resection or local ablation therapy. Diagnostic methods for small HCCs have improved with the introduction of gadoxetic acid-enhanced liver magnetic resonance imaging and diffusion-weighted imaging (DWI). Currently, sub-centimeter recurrent nodules showing typical hallmark imaging findings of HCC are frequently detected in patients with a treatment history for HCC. With five typical magnetic resonance findings, including arterial enhancement, washout on portal or transitional phase, high signal intensity on both T2-weighted image and DWI, and low signal intensity on hepatobiliary phase, sub-centimeter recurrent HCC can be diagnosed with high accuracy. Although more information is needed to determine the treatment of choice, local ablation therapy under fusion imaging and/or contrast-enhanced ultrasound guidance or cone-beam computed tomography-guided chemoembolization seem to be promising as they are effective and safe for the management of sub-centimeter recurrent HCCs.

Topics: Ablation Techniques; Carcinoma, Hepatocellular; Cone-Beam Computed Tomography; Contrast Media; Diffusion Magnetic Resonance Imaging; Gadolinium DTPA; Humans; Liver; Liver Neoplasms; Neoplasm Recurrence, Local; Treatment Outcome; Ultrasonography, Interventional

PubMed: 30581270
DOI: 10.3748/wjg.v24.i46.5215

Authors: Lambert Wanninger, Anja Heßelbarth, Volker Frevert...

In 2020, Garmin released one of the first consumer devices with a dual-frequency GNSS chip and a quadrifilar helix antenna: GPSMAP 66sr. The device is intended to serve as a positioning and navigation device for outdoor recreation purposes with positioning accuracies on the few meter level. However, due to its highly accurate GNSS dual-frequency carrier-phase observations, the equipment can also be used for centimeter-accurate positioning. We performed extensive test measurements and analyzed the quality of its code and carrier-phase observations. We calibrated the Garmin GPSMAP 66sr antenna with respect to its phase-center offset and phase-center variations. We also performed dual-frequency GPS/Galileo precise point positioning (PPP) and precise relative positioning in baselines to virtual reference stations (VRS). We demonstrate and explain how centimeter-accurate positioning can be achieved with this novel kind of equipment.

PubMed: 35271109
DOI: 10.3390/s22051964