Ferumoxytol-enhanced MR venography for mapping lower-extremity venous networks and evaluating varicose veins in patients with diabetes.

OBJECTIVES: Comprehensive evaluation of lower-extremity varicose veins (VVs) in patients with diabetes is crucial for treatment strategizing. The study aims to assess the feasibility of using ferumoxytol-enhanced MR venography (FE-MRV) for lower-extremity venous mapping and the detection of VVs in patients with diabetes. MATERIALS AND METHODS: As part of a phase II clinical trial of a generic brand of ferumoxytol, documented patients with diabetes were enrolled and underwent FE-MRV on a 3-Τ MRI system. Two observers assessed FE-MRV images for image quality, signal intensity ratio (SIR), perforator (PV) diameter, and luminal signal uniformity in deep-to-superficial venous networks with the assessment of intra- and inter-rater reliability. FE-MRV was used to detect lower-extremity VVs. RESULTS: Eleven patients underwent FE-MRV without adverse events. The average image quality, as scored by the two observers who assessed 275 venous segments, was 3.4 ± 0.6. Two observers strongly agreed on image quality (κ = 0.90) and SIR measurements (interclass correlation coefficient [ICC]: 0.72) and had good agreement on PV diameter (ICC: 0.64). FE-MRV revealed uniform luminal signals in deep and saphenous venous networks (0.13 ± 0.05 vs 0.08 ± 0.03). Below-knee segments exhibited a significantly higher heterogeneity index than above-knee (p = 0.039) segments. Superficial VVs were observed in 55% (12/22) of legs in 64% (7/11) of patients. Calf muscle VVs were present in 64% (14/22) of legs in 9 patients. CONCLUSION: FE-MRV safely and robustly mapped entire lower-extremity venous networks, enabling the detection and pre-treatment evaluation of both superficial, and deep VVs in patients with diabetes. CLINICAL RELEVANCE STATEMENT: Ferumoxytol-enhanced magnetic resonance venography offers a "one-stop" imaging strategy for the detection and pre-operative evaluation of both superficial and deep VVs in diabetic patients. KEY POINTS: Diabetic patients with VVs are at a higher risk of ulcer-related complications. FE-MRV allowed rapid and comprehensive visualization of the lower-limb venous networks and abdominopelvic veins in diabetic patients. This technique allowed for the detection of superficial and deep VVs in diabetic patients before the development of severe peripheral artery disease.

Smartphone-assisted portable swabs for blood glucose management: A point-of-use assay for dual-mode visual detection based on bifunctional carbon dots.

Controlling glucose (Glu) intake is a "required course" for diabetics, thus quickly and precisely measuring the amount of Glu in food is crucial. For this purpose, a novel smartphone-assisted portable swab for the dual-mode visual detection of Glu was constructed combined the selectivity of natural enzymes with the controllable catalytic activity of nanozymes. Glu was specifically decomposed by glucose oxidase (natural enzyme) to produce H2O2, which was catalyzed by carbon dots (FeMn/N-CDs, nanozyme) to accelerate the reaction of o-phenylenediamine (OPD, colorless) to produce 2,3-diaminophenazine (DAP, yellow). As a result, the absorbance at 450 nm gradually increased with the increasing concentration of Glu, leading to a color change in the system from colorless to yellow. Meanwhile, the fluorescence of FeMn/N-CDs gradually decreased at 450 nm, while the fluorescence of DAP gradually increased at 550 nm, allowing for both ratiometric fluorescence and colorimetric dual-mode detection. Furthermore, natural enzyme and nanozyme together with OPD were co-loaded on the swabs to achieve cascade catalysis of Glu. The assembled portable swabs have detection ranges of 1-600 µM (LOD = 0.37 µM) and 4-1200 µM (LOD = 1.19 µM) for the colorimetric and fluorometric detection, respectively. The field test results on real samples demonstrated that the portable swabs have great promise for use in efficiently and accurately guiding the dietary intake of diabetics.

Iron-carbon dots embedded in molybdenum single-atom nanoflowers as multifunctional nanozyme for dual-mode detection of hydrogen peroxide and uric acid.

Single-atom catalysts (SACs) have attracted extensive attention in the field of catalysis due to their excellent catalytic ability and enhanced atomic utilization, but the multi-mode single-atom nanozymes for biosensors remain a challenging issue. In this work, iron-doped carbon dots (Fe CDs) were loaded onto the edges and pores of Mo SACs with nanoflower morphology; accordingly, a composite material Fe CDs/Mo SACs was prepared successfully, which improves the catalytic performance and develops a fluorescence mode without changing the original morphology. The steady-state kinetic data indicates that the material prepared have better affinity for substrates and faster reaction rates under optimized conditions. The specific kinetic parameters Km and Vmax were calculated as 0.39 mM and 7.502×10-7 M·s-1 respectively. The excellent peroxidase-like activity of Fe CDs/Mo SACs allows H2O2 to decompose into •OH, which in turn oxidizes colorless o-phenylenediamine (OPD) to yellow 2,3-diaminophenazine (DAP). At the same time, the fluorescence signal of Fe CDs/Mo SACs quenches obviously by DAP at 460 nm through internal filtration effect (IFE), while the characteristic fluorescence response of DAP gradually increases at 590 nm. Based on this sensing mechanism, a sensitive and accurate dual-mode (colorimetric and ratiometric fluorescent) sensor was constructed to detect H2O2 and uric acid, and the rate of recovery and linearity were acceptable for the detection of UA in human serum and urine samples. This method provides a new strategy for rapid and sensitive detection of UA, and also broadens the development of SACs in the field of biosensors.