Visible-Light-Mediated Metal-Free Hydrosilylation of Alkenes through Selective Hydrogen Atom Transfer for Si-H Activation.

Although there has been significant progress in the development of transition-metal-catalyzed hydrosilylations of alkenes over the past several decades, metal-free hydrosilylation is still rare and highly desirable. Herein, we report a convenient visible-light-driven metal-free hydrosilylation of both electron-deficient and electron-rich alkenes that proceeds through selective hydrogen atom transfer for Si-H activation. The synergistic combination of the organophotoredox catalyst 4CzIPN with quinuclidin-3-yl acetate enabled the hydrosilylation of electron-deficient alkenes by selective Si-H activation while the hydrosilylation of electron-rich alkenes was achieved by merging photoredox and polarity-reversal catalysis.

Deciphering Nanoparticle Trafficking into Glioblastomas Uncovers an Augmented Antitumor Effect of Metronomic Chemotherapy.

Nanoparticles have been explored in glioblastomas as they can traverse the blood-brain barrier and target glioblastoma selectively. However, direct observation of nanoparticle trafficking into glioblastoma cells and their underlying intracellular fate after systemic administration remains uncharacterized. Here, based on high-resolution transmission electron microscopy experiments of an intracranial glioblastoma model, it is shown that ligand-modified nanoparticles can traverse the blood-brain barrier, endocytose into the lysosomes of glioblastoma cells, and undergo endolysosomal escape upon photochemical ionization. Moreover, an optimal dose of metronomic chemotherapy using dual-drug-loaded nanocarriers can induce an augmented antitumor effect directly on tumors, which has not been recognized in previous studies. Metronomic chemotherapy enhances antitumor effects 3.5-fold compared with the standard chemotherapy regimen using the same accumulative dose in vivo. This study provides a conceptual framework that can be used to develop metronomic nanoparticle regimens as a safe and viable therapeutic strategy for treating glioblastomas and other advanced-stage solid tumors.

Stimuli-Responsive Memristive Materials for Artificial Synapses and Neuromorphic Computing.

Neuromorphic computing holds promise for building next-generation intelligent systems in a more energy-efficient way than the conventional von Neumann computing architecture. Memristive hardware, which mimics biological neurons and synapses, offers high-speed operation and low power consumption, enabling energy- and area-efficient, brain-inspired computing. Here, recent advances in memristive materials and strategies that emulate synaptic functions for neuromorphic computing are highlighted. The working principles and characteristics of biological neurons and synapses, which can be mimicked by memristive devices, are presented. Besides device structures and operation with different external stimuli such as electric, magnetic, and optical fields, how memristive materials with a rich variety of underlying physical mechanisms can allow fast, reliable, and low-power neuromorphic applications is also discussed. Finally, device requirements are examined and a perspective on challenges in developing memristive materials for device engineering and computing science is given.

Emerging strategies in developing multifunctional nanomaterials for cancer nanotheranostics.

Cancer involves a collection of diseases with a common trait - dysregulation in cell proliferation. At present, traditional therapeutic strategies against cancer have limitations in tackling various tumors in clinical settings. These include chemotherapeutic resistance and the inability to overcome intrinsic physiological barriers to drug delivery. Nanomaterials have presented promising strategies for tumor treatment in recent years. Nanotheranostics combine therapeutic and bioimaging functionalities at the single nanoparticle level and have experienced tremendous growth over the past few years. This review highlights recent developments of advanced nanomaterials and nanotheranostics in three main directions: stimulus-responsive nanomaterials, nanocarriers targeting the tumor microenvironment, and emerging nanomaterials that integrate with phototherapies and immunotherapies. We also discuss the cytotoxicity and outlook of next-generation nanomaterials towards clinical implementation.

Combating the Coronavirus Pandemic: Early Detection, Medical Treatment, and a Concerted Effort by the Global Community.

The World Health Organization (WHO) has declared the outbreak of 2019 novel coronavirus, known as 2019-nCoV, a pandemic, as the coronavirus has now infected over 2.6 million people globally and caused more than 185,000 fatalities as of April 23, 2020. Coronavirus disease 2019 (COVID-19) causes a respiratory illness with symptoms such as dry cough, fever, sudden loss of smell, and, in more severe cases, difficulty breathing. To date, there is no specific vaccine or treatment proven effective against this viral disease. Early and accurate diagnosis of COVID-19 is thus critical to curbing its spread and improving health outcomes. Reverse transcription-polymerase chain reaction (RT-PCR) is commonly used to detect the presence of COVID-19. Other techniques, such as recombinase polymerase amplification (RPA), loop-mediated isothermal amplification (LAMP), clustered regularly interspaced short palindromic repeats (CRISPR), and microfluidics, have allowed better disease diagnosis. Here, as part of the effort to expand screening capacity, we review advances and challenges in the rapid detection of COVID-19 by targeting nucleic acids, antigens, or antibodies. We also summarize potential treatments and vaccines against COVID-19 and discuss ongoing clinical trials of interventions to reduce viral progression.