A non-residue surface modification strategy for active-targeting fluorescent silica nanoparticles to cellular organelles.

Silica nanoparticles (SiNPs) with a chemically modified surface typically have a complicated chemical composition, which can significantly differ from their intended design. In this study, we systematically studied the effects of two surface modification methods on active-targeting of intracellular organelles of SiNPs: (1) the widely used step-by-step approach, which involves modifying SiNPs in two steps, i.e., the outer surface of SiNPs was firstly modified with amino groups and then these amino groups were linked with targeting groups, and (2) a newly developed one-step approach in which the ligand-silane complex is initially synthesized, followed by chemically immobilizing the complex on the surface of SiNPs. In the one-step approach, the molar ratio of reactants was precisely tuned so that there are no reactive groups left on the outer surface of SiNPs. Two essential organelles, mitochondria and the nucleus, were selected to compare the targeting performances of SiNPs synthesized via these two approaches. By characterizing physicochemical properties, including structural properties, the number of amino groups, surface charge, polydispersity, and cell colocalization, we demonstrated that SiNPs synthesized via the one-step approach with no residual linkage groups on their surface showed significantly improved mitochondria- and nucleus-targeting performances. This precise control of surface properties allows for optimized biological behavior and active-targeting efficiency of SiNPs. We anticipate that such simple and efficient synthetic strategies will enable the synthesis of effective SiNPs for active-targeting organelles in various biological applications.

Near-infrared responsive gold nanorods for highly sensitive colorimetric and photothermal lateral flow immuno-detection of SARS-CoV-2.

The highly infectious characteristics of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), highlight the necessity of sensitive and rapid nucleocapsid (N) protein-based antigen testing for early triage and epidemic management. In this study, a colorimetric and photothermal dual-mode lateral flow immunoassay (LFIA) platform for the rapid and sensitive detection of the SARS-CoV-2 N protein was developed based on gold nanorods (GNRs), which possessed tunable local surface plasma resonance (LSPR) absorption peaks from UV-visible to near-infrared (NIR). The LSPR peak was adjusted to match the NIR emission laser 808 nm by controlling the length-to-diameter ratio, which could maximize the photothermal conversion efficiency and achieve photothermal detection signal amplification. Qualitative detection of SARS-CoV-2 N protein was achieved by observing the strip color, and the limit of detection was 2 ng mL-1, while that for photothermal detection was 0.096 ng mL-1. Artificial saliva samples spiked with the N protein were analyzed with the recoveries ranging from 84.38% to 107.72%. The intra-assay and inter-assay coefficients of variation were 6.76% and 10.39%, respectively. We further evaluated the reliability of this platform by detecting 40 clinical samples collected from nasal swabs, and the results matched well with that of nucleic acid detection (87.5%). This method shows great promise in early disease diagnosis and screening.

Direct Bilirubin, but not Indirect Bilirubin, is Associated with Short-term Adverse Events in HFpEF.

OBJECTIVE: Abnormal live function tests have been identified as independent risk factors for ominous prognosis in patients with heart failure. However, most of the previous studies have failed to determine the contribution of direct bilirubin (DBIL) and indirect bilirubin (IBIL) separately. Hence, we aimed to explore whether DBIL or IBIL is correlated with the prognosis of heart failure with preserved ejection fraction (HFpEF). METHODS: A total of 19837 patients were hospitalized for HFpEF between January 2012 and January 2022 in Fuqing City Hospital affiliated with Fujian Medical University. The primary endpoint was in-hospital all-cause mortality. Secondary endpoints included in-hospital cardiovascular mortality and 30-day re-admission for heart failure. RESULTS: Univariable analysis indicated that patients with elevated DBIL or IBIL were exposed to a higher risk of mortality and re-admission. However, in multivariable models, both ln-transformed DBIL and TBIL, but not IBIL, were independent risk factors for in-hospital all-cause mortality (hazard ratio (HR)=1.796, 95% confidential interval (CI)=1.477-2.183, P<0.001; HR=1.854, 95% CI=1.461-2.352, P.0.001; HR=1.161, 95% CI=0.959-1.407, P=0.126) and in-hospital cardiovascular mortality (HR=1.831, 95% CI=1.345-2.492, P.0.001; HR=1.899, 95% CI=1.300-2.773, P=0.001; HR=1.145, 95% CI=0.841-1.561, P=0.389). Only DBIL remained independently associated with 30-day readmission for heart failure (HR=1.361, 95% CI=1.036-1.787, P=0.027). Adding ln-transformed DBIL to model 1 increased its discriminatory capacity (C-statistic: 0.851 to 0.869, respectively), whereas adding ln-transformed IBIL yielded little increment (C-statistic: 0.851 to 0.852, respectively). CONCLUSION: DBIL, but not IBIL, was associated with short-term ominous prognosis in patients with HFpEF. Hence, DBIL may be the superior predictor for prognosis in HFpEF.