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.
A nonemissive cyclometalated iridium(III) solvent complex, without conjugation with a cell-penetrating molecular transporter, [Ir(ppy)(2)(DMSO)(2)](+)PF(6)(-) (LIr1), has been developed as a first reaction-based fluorescence-turn-on agent for the nuclei of living cells. LIr1 can rapidly and selectively light-up the nuclei of living cells over fixed cells, giving rise to a significant luminescence enhancement (200-fold), and shows very low cytotoxicity at the imaging concentration (incubation time <10 min, LIr1 concentration 10 μM). More importantly, in contrast to the reported nuclear stains that are based on luminescence enhancement through interaction with nucleic acids, complex LIr1 as a nuclear stain has a reaction-based mode of action, which relies on its rapid reaction with histidine/histidine-containing proteins. Cellular uptake of LIr1 has been investigated in detail under different conditions, such as at various temperatures, with hypertonic treatment, and in the presence of metabolic and endocytic inhibitors. The results have indicated that LIr1 permeates the outer and nuclear membranes of living cells through an energy-dependent entry pathway within a few minutes. As determined by an inductively coupled plasma atomic emission spectroscopy (ICP-AEC), LIr1 is accumulated in the nuclei of living cells and converted into an intensely emissive adduct. Such novel reaction-based nuclear staining for visualizing exclusively the nuclei of living cells with a significant luminescence enhancement may extend the arsenal of currently available fluorescent stains for specific staining of cellular compartments.
A novel method of rare-earth cation-assisted ligand assembly has been developed to provide upconversion nanophosphors with T(1)-enhanced magnetic resonance (MR), radioactivity, and targeted recognition properties, making these nanoparticles potential candidates for multimodal bioimaging. The process of modifying the surface of the nanophosphors has been confirmed by transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, proton nuclear magnetic resonance, Fourier-transform infrared spectroscopy, energy-dispersive X-ray analysis, and so on. The versatility of this surface modification approach for incorporating functional molecules and fabricating fluorine-18-labeled magnetic-upconversion nanophosphors as multimodal bioprobes has been demonstrated by targeted cell imaging, in vivo upconversion luminescence, MR imaging, and positron emission tomography imaging of whole-body small animals.
Phototrigger‐controlled drug‐release devices (PDDs) can be conveniently manipulated by light to obtain on‐demand release patterns, thereby affording an improved therapeutic efficacy. However, no example of the PDDs has been demonstrated beyond the cellular level to date. By loading 7‐amino‐coumarin derivative caged anticancer drug chlorambucil to yolk–shell structured nanocages possessing upconversion nanophosphors (UCNPs) as moveable core and silica as mesoporous shell, a near‐infrared (NIR)‐regulated PDD is successfully created. In vitro experiments demonstrate that drug release from the PDD could be triggered by continuous‐wave 980 nm light in a controlled pattern. The PDD could be taken up by cancer cells and release the drug to kill cancer cells upon NIR irradiation. Further in vivo studies demonstrate that the PDD can effectively response the NIR stimuli in living tissue. This is the first example of successful NIR‐regulated drug release in living animal model. Such achievement resolves the problem of low tissue penetration depth for traditional PDDs by adopting UCNPs as an NIR light switcher, which gives impetus to practical applications.
Chromophoric iridium(III) complex-coated NaYF(4): 20%Yb, 1.6%Er, 0.4%Tm nanocrystals are demonstrated as a ratiometric upconversion luminescence (UCL) probe for highly selective detection of cyanide anion and bioimaging of CN(-) in living cells through inhibition of the energy transfer from the UCL of the nanocrystals to the absorbance of the chromophoric complex. The UCL probe provides a very low detection limit of 0.18 μM CN(-) in the aqueous solution.
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