Dye Sensitization Offers a Brighter Afterglow Nanoparticle Future for in vivo Recharged Luminescent Imaging

While concerns about improving recharged afterglow intensity in vivo still motivate further exploration, afterglow nanoparticles (AGNP) offer unique optical merit for autofluorescence-free biological imaging. Apart from efforts enhancing the afterglow emission properties of AGNP, improving afterglow excitation response to visible or near infrared light is important but has lacked success. Dye sensitization has been used to improve the optical response of photovoltaic nanomaterials and to enhance upconversion luminescence efficiency. This concept has recently been expanded and applied to AGNPs. As a new multifunctional nanoprobe, such dye-sensitized AGNP takes advantage of both high spatial resolution fluorescence imaging and sensitive afterglow imaging. This Concept introduces the background, the concept, mechanism, and related imaging application, as well as reviewing existing challenges and proposing future developmental directions for the dye-sensitized AGNPs.     

DSA、CTA联合MR影像评估AIS患者脑支循环及预后性关系

探讨数字减影血管成像(DSA)、计算机断层扫描血管成像(CTA)联合磁共振(MR)影像评估急性缺血性卒中(AIS)患者脑支循环及预后性关系。选取60例大脑中动脉M1段急性闭塞所致AIS患者为研究对象,根据DSA、CTA与MR影像对其脑侧支循环评估,比较患者基线资料、结局指标等,并分析预后性。结果发现:基于DSA、CTA与MR影像对AIS患者脑侧支循环评估结果一致性良好;3种影像模式下脑侧支循环良好组与不良组结局资料差异显著(P<0.05);多因素分析显示,FVH-ASPECTS评分、rLMC评分、ASITN/SIR分级量表均为AIS患者神经功能预后的独立影响因素。总之,DSA、CTA、MR影像对AIS患者脑侧支循环评估具有一致性,且FVH-ASPECTS评分、rLMC评分、ASITN/SIR分级量表均为AIS患者神经功能预后的独立影响因素。     

Perspectives of magnetic nature carbon dots in analytical chemistry: From separation to detection and bioimaging

Magnetic nature carbon dots (MNCDs) are fast growing materials with extremely unique physico-chemical properties and physiological ability to extend their applications from separation science to detection and bio-/magnetic resonance imaging applications. Recent studies have revealed that the MNCDs are significantly used as promising agents in analytical chemistry for the separation and identification of trace level target analytes. Further, the MNCDs have been used as probes for bioimaging of cells and magnetic resonance imaging (MRI) of tumors. Due to the lack of comprehensive reviews in this emerging field especially MNCDs applications in analytical chemistry, this review may provide quick guide and reference on the MNCDs-based analytical approaches for the separation and detection of trace level analytes, and bio- and MR- imaging of various cells. In this review article, we will summarize the synthetic approaches for the fabrication of MNCDs. The main part of this proposed review is devoted to the tremendous applications of MNCDs (Fe₃O₄@CDs, metal ion (Fe³⁺, Mn²⁺, Co²⁺ and Gd²⁺)-doped CDs, MnO₂@CDs) in analytical chemistry from separation science to detection and bio- and MR imaging. Finally, we will explore the challenges and future prospects of magneto fluorescent carbon dots in biomedical applications.     

Distinguishing and quantification of the human visual pathways using high-spatial-resolution diffusion tensor tractography

Quantification of the living human visual system using MRI methods has been challenging, but several applications demand a reliable and time-efficient data acquisition protocol. In this study, we demonstrate the utility of high-spatial-resolution diffusion tensor fiber tractography (DTT) in reconstructing and quantifying the human visual pathways. Five healthy males, age range 24–37 years, were studied after approval of the institutional review board (IRB) at The University of Texas Health Science Center at Houston. We acquired diffusion tensor imaging (DTI) data with 1-mm slice thickness on a 3.0-Tesla clinical MRI scanner and analyzed the data using DTT with the fiber assignment by continuous tractography (FACT) algorithm. By utilizing the high-spatial-resolution DTI protocol with FACT algorithm, we were able to reconstruct and quantify bilateral optic pathways including the optic chiasm, optic tract, optic radiations free of contamination from neighboring white matter tracts.     

3D photon counting imaging at 1550 nm with 1.5-GHz sine-wave-gated InGaAs/InP GAPD

We demonstrated a 3D laser imaging system at 1550 nm with a 1.5-GHz sine-wave gated Geiger-mode InGaAs/InP avalanche photodiode (APD). An optical fiber bundle with 100 individual fiber outputs was implemented at the focal plane of the telescope, providing a 2.5-mrad imaging view. The system used single-pixel near-infrared single-photon detector to measure photons at fiber outputs instead of a photon counting array. The 1.5-GHz gated Geiger-mode InGaAs/InP APD with a timing jitter of 290 ps was operated in quasi-continuous mode with detection efficiency of ∼4.3%. We achieved higher than 6-cm surface-to-surface resolution at single-photon level, showing a potential of low-energy and eye-safe laser imaging system for long-distance measurements.     

Hydroxy double salts intercalated with Mn(II) complexes as potential contrast agents

A series of Mn(II) aminophosphonate complexes were successfully synthesized and intercalated into the hydroxy double salt [Zn₅(OH)₈]Cl₂·yH₂O. Complex incorporation led to an increase in the interlayer spacing from 7.8 to 10–12 Å. Infrared spectroscopy showed the presence of the characteristic vibration peaks of the Mn(II) complexes in the intercalates' spectra, indicating successful incorporation. The complex-loaded composites had somewhat lower proton relaxivities than the pure complexes. Nevertheless, these intercalates may have use as MRI contrast agents for patients with poor kidney function, where traditional Gd(III)-based contrast agents cause severe renal failure.     

A Lysosome‐Compatible Near‐Infrared Fluorescent Probe for Targeted Monitoring of Nitric Oxide

The requirement for nitric oxide (NO) of lysosomes has motivated the development of a sophisticated fluorescent probe to monitor the distribution of this important biomolecule at the subcellular level in living cells. A near‐infrared (NIR) fluorescent Si‐rhodamine (SiRB)‐NO probe was designed based on the NO‐induced ring‐opening process of Si‐rhodamine. The probe exhibits fast chromogenic and fluorogenic responses, and high sensitivity and selectivity toward trace amounts of NO. Significantly, the spirolactam in Si‐rhodamine exhibits very good tolerance to H⁺, which in turn brings extremely low background fluorescence not only in the physiological environment but also under acidic conditions. The stability of the highly fluorescent product in acidic solution provides persistent fluorescence emission for long‐term imaging experiments. To achieve targeted imaging with improved spatial resolution and sensitivity, an efficient lysosome‐targeting moiety was conjugated to a SiRB‐NO probe, affording a tailored lysosome‐targeting NIR fluorescent Lyso‐SiRB‐NO probe. Inheriting the key advantages of its parent SiRB‐NO probe, Lyso‐SiRB‐NO is a functional probe that is suited for monitoring lysosomal NO with excellent lysosome compatibility. Imaging experiments demonstrated the monitoring of both exogenous and endogenous NO in real time by using the Lyso‐SiRB‐NO probe.