BACKGROUND: The coronavirus disease 2019, caused by severe acute respiratory syndrome coronavirus 2, is a global public health emergency. Data on the effect of coronavirus disease 2019 in pregnancy are limited to small case series. OBJECTIVE: To evaluate the clinical characteristics and outcomes in pregnancy and the vertical transmission potential of severe acute respiratory syndrome coronavirus 2 infection.

Enhanced near-field at noble metal nanoparticle surfaces due to localized surface plasmon resonance (LSPR) has been researched in fields ranging from biomedical to photoelectrical applications. However, it is rarely explored on nonmetallic nanomaterials discovered in recent years, which can also support LSPR by doping-induced free charge carriers, let alone the investigation of an intricate system involving both. Here we construct a dual plasmonic hybrid nanosystem Au-Cu9S5 with well controlled interfaces to study the coupling effect of LSPR originating from the collective electron and hole oscillations. Cu9S5 LSPR is enhanced by 50% in the presence of Au, and the simulation results confirm the coupling effect and the enhanced local field as well as the optical power absorption on Cu9S5 surface. This enhanced optical absorption cross section, high photothermal transduction efficiency (37%), large light penetration depth at 1064 nm, excellent X-ray attenuation ability, and low cytotoxicity enable Au-Cu9S5 hybrids for robust photothermal therapy in the second near-infrared (NIR) window with low nanomaterial dose and laser flux, making them potential theranostic nanomaterials with X-ray CT imaging capability. This study will benefit future design and optimization of photoabsorbers and photothermal nanoheaters utilizing surface plasmon resonance enhancement phenomena for a broad range of applications.

Fluorescence imaging has become a fundamental tool for biomedical applications; nevertheless, its intravital imaging capacity in the conventional wavelength range (400−950 nm) has been restricted by its extremely limited tissue penetration. To tackle this challenge, a novel imaging approach using the fluorescence in the second near-infrared window (NIR-II, 1000−1700 nm) has been developed in the past decade to achieve deep penetration and high-fidelity imaging, and thus significant biomedical applications have begun to emerge. In this Perspective, we first examine recent discoveries and challenges in the development of novel NIR-II fluorophores and compatible imaging apparatuses. Subsequently, the recent advances in bioimaging, biosensing, and therapy using such a cutting-edge imaging technique are highlighted. Finally, based on the achievement in the representative studies, we elucidate the main concerns regarding this imaging technique and give some advice and prospects for the development of NIR-II imaging for future biomedical applications.