as 2019-nCoV), [1] has caused more than 83 million infections and 1.8 million deaths globally as of January 1, 2021. [2] In the past 200 years, multiple epidemics induced by emerging viruses, such as SARS-CoV, Zika virus, Ebola virus, and recently SARS-CoV-2, have posed unprecedented threats to global public health. [3] Although several vaccine candidates have been approved by the U.S. Food and Drug Administration (FDA) for emergency prevention of SARS-CoV-2 infection, so far there is still absence of effective therapeutic options for patients with COVID-19. [4] Thus, it is of paramount importance to develop therapeutic approaches for COVID-19 and other potential pandemics.Similar to SARS-CoV infection, SARS-CoV-2 relies on spike proteins and angiotensin-converting enzyme 2 (ACE2) receptors for cell infection. [5][6][7] Once the virus enters human body, macrophages and monocytes secrete abundant proinflammatory cytokines, promoting pathogen elimination and tissue recovery. However, an exaggerated release of cytokines, known as a "cytokine storm" (or "cytokine release syndrome"), may worsen inflammatory status and result in immune-system-initiated organ damage. [8] Clinically, the majority of patients with COVID-19 appear asymptomatic or mildly symptomatic, while ≈20% of COVID-19 cases developThe COVID-19 pandemic, induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused great impact on the global economy and people's daily life. In the clinic, most patients with COVID-19 show none or mild symptoms, while approximately 20% of them develop severe pneumonia, multiple organ failure, or septic shock due to infection-induced cytokine release syndrome (the so-called "cytokine storm"). Neutralizing antibodies targeting inflammatory cytokines may potentially curb immunopathology caused by COVID-19; however, the complexity of cytokine interactions and the multiplicity of cytokine targets make attenuating the cytokine storm challenging. Nonspecific in vivo biodistribution and dose-limiting side effects further limit the broad application of those free antibodies. Recent advances in biomaterials and nanotechnology have offered many promising opportunities for infectious and inflammatory diseases. Here, potential mechanisms of COVID-19 cytokine storm are first discussed, and relevant therapeutic strategies and ongoing clinical trials are then reviewed. Furthermore, recent research involving emerging biomaterials for improving antibody-based and broad-spectrum cytokine neutralization is summarized. It is anticipated that this work will provide insights on the development of novel therapeutics toward efficacious management of COVID-19 cytokine storm and other inflammatory diseases.

Rational: Interstitial brachytherapy (BT) is a promising radiation therapy for cancer; however, the efficacy of BT is limited by tumor radioresistance. Recent advances in materials science and nanotechnology have offered many new opportunities for BT. Methods: In this work, we developed a biomimetic nanotheranostic platform for enhanced BT. Core-shell Au@AuPd nanospheres (CANS) were synthesized and then encapsulated in platelet (PLT)-derived plasma membranes. Results: The resulting PLT/CANS nanoparticles efficiently evaded immune clearance and specifically accumulated in tumor tissues due to the targeting capabilities of the PLT membrane coating. Under endoscopic guidance, a BT needle was manipulated to deliver appropriate radiation doses to orthotopic colon tumors while sparing surrounding organs. Accumulated PLT/CANS enhanced the irradiation dose deposition in tumor tissue while alleviating tumor hypoxia by catalyzing endogenous H 2 O 2 to produce O 2 . After treatment with PLT/CANS and BT, 100% of mice survived for 30 days. Conclusions: Our work presents a safe, robust, and efficient strategy for enhancing BT outcomes when adapted to treatment of intracavitary and unresectable tumors.

No abstract