Metabolic magnetic resonance imaging (MRI) using hyperpolarized (HP) pyruvate is becoming a non‐invasive technique for diagnosing, staging, and monitoring response to treatment in cancer and other diseases. The clinically established method for producing HP pyruvate, dissolution dynamic nuclear polarization, however, is rather complex and slow. Signal Amplification By Reversible Exchange (SABRE) is an ultra‐fast and low‐cost method based on fast chemical exchange. Here, for the first time, we demonstrate not only in vivo utility, but also metabolic MRI with SABRE. We present a novel routine to produce aqueous HP [1‐13C]pyruvate‐d3 for injection in 6 minutes. The injected solution was sterile, non‐toxic, pH neutral and contained ≈30 mM [1‐13C]pyruvate‐d3 polarized to ≈11 % (residual 250 mM methanol and 20 μM catalyst). It was obtained by rapid solvent evaporation and metal filtering, which we detail in this manuscript. This achievement makes HP pyruvate MRI available to a wide biomedical community for fast metabolic imaging of living organisms.
A new method is described for the determination of the pesticide λ-cyhalothrin (LC). It combines SERS detection with molecular imprinting and largely improves selectivity. A multilayer surface imprinted nanocomposite was synthesized in two steps on a nanostructure of type SiO@rGO@Ag acting as a substrates. Firstly, the surface of the SiO@rGO@Ag composite was modified with self-polymerized dopamine. Secondly, surface-initiated polymerization was carried out to prepare a molecularly imprinted polymer (MIP) using LC as the template. The use of this SiO@rGO@Ag-MIP allows for excellent SERS based detection and has high selectivity for LC. The Raman intensity and LC concentration present perfect linear relationship between 10 to 10 mol L and the detection limit is 3.8×10 mol L. All the procedures are conducted in aqueous or ethanol solution. Graphical abstract Schematic of a new method for determination of the pesticide λ-cyhalothrin. It combines SERS detection with molecular imprinting and largely improves selectivity. A multilayer surface imprinted nanocomposite was synthesized in two steps on a nanostructure of type SiO@rGO@Ag acting as a substrates.
Novel molecularly imprinted polymers (MIPs) based on the technique of surface-enhanced Raman scattering (SERS) were successfully prepared. Firstly, ZnO nanorods were fabricated with Ag by reduction of Ag on the surface of the ZnO nanorods. Then, ZnO/Ag heterostructures were used as the substrate, rhodamine 6G was used as the template molecule, acrylamide was used as the functional monomer, ethylene glycol dimethacrylate was used as the cross-linker, and 2,2'-azobis(2-methylpropionitrile) was used as the initiator to prepare the ZnO/Ag MIPs (ZOA-MIPs). Through characterization analysis, it was proved that the novel ZOA-MIPs exhibited excellent SERS properties and selectivity. Under the optimal conditions, there was a good linear relationship (R = 0.996) between the Raman signal (at 1654 cm) and the concentration of the templates, and the detection limit was 10 mol L. It was also proved that the ZOA-MIPs had the property of self-cleaning, resulting in good reusability. It is envisaged that the sensitivity of SERS coupled with the selectivity of MIPs could result in a promising chemosensor for practical applications.
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