Surface-Enhanced Raman Spectroscopy on Liquid Interfacial Nanoparticle Arrays for Multiplex Detecting Drugs in Urine

The design and application of liquid interfacial plasmonic platform is still in its infancy but is an exciting topic in tunable optical devices, sensors, and catalysis. Here, we developed an interfacial surface-enhanced Raman scattering (SERS) platform through the large-scale self-assembly of gold nanoparticle (GNP) arrays at the cyclohexane (CYH)/water interface for detecting trace drug molecules in the urine of humans. The molecules extracted by the CYH phase from a urine sample were directly localized into the self-organized plasmonic hotspots, yielded excellent Raman enhancement, and realized the substrate-free interfacial SERS detection. Synchrotron radiation small-angle X-ray scattering (SR-SAXS) experiments reveals a good uniformity of approximately 2–3 nm interparticle distance in the GNP arrays. SERS colocalization experiments demonstrated that amphetamine molecules of different concentration levels could be loaded into the interfacial GNP arrays and realized the coassembly together with nanoparticles at the liquid/liquid interface. Interfacial GNP arrays with dynamic nanogaps in liquid interfacial structure can make surrounding molecules easily diffuse into the nanogaps. In contrast, the fixed GNP arrays on Si wafer were more irregular, such as multilayer stack, random aggregates, and voids, during the drying process. When the drugs directly participate in the self-assembly process, it becomes easier for analytes diffusing into the nanogaps of GNP arrays, produces a concentration effect, and amplified the SERS sensitivity. This feature also enables molecules to be adsorbed evenly in the arrays and makes a more uniform distribution of both the analytes and GNPs in the liquid interface and realizes the significant increase in signal reproducibility. Interfacial SERS produced a standard deviation of 12.5% at 1001 cm^–1 peak of methamphetamine (MAMP) molecules under the concentration of 1 ppm, implying a good reproducibility. Moreover, dual-analyte detection at organic and aqueous phases was also realized and confirmed a good capability for analytes detection by liquid interfacial SERS platform, which promises nonengineering detection of analytes dissolved in often-inaccessible environments

Amphiphilic Functionalized Acupuncture Needle as SERS Sensor for In Situ Multiphase Detection

Surface enhanced Raman spectroscopy (SERS) is a powerful spectroscopic technique with unique vibrational fingerprints, making it an ideal candidate for in situ multiphase detection. However, it is a great challenge to determine how to guide the SERS sensor to target molecules of interest in multiphase heterogeneous samples with minimal disturbance. Here, we present a portable ultrasensitive and highly repeatable SERS sensor for in situ multiphase detection. The sensor is composed of commercial Ag acupuncture needle and PVP-Au nanoparticles (Au NPs). The PVP on the Au NPs can adsorb and induce the Au NPs into a highly uniform array on the surface of the Ag needle because of its adhesiveness and steric nature. The Au NPs-Ag Needle system (Au-AgN) holds a huge SERS effect, which is enabled by the multiple plasmonic couplings from particle–film and interparticle. The PVP, as the amphiphilic polymer, promotes the target molecules to adsorb on surface of the Au-AgN whether in the oil phase or in the water phase. In this work, the Au-AgN sensor was directly inserted into the multiphase system with the laser in situ detection, and SERS detection at different spots of the Au-AgN sensor provided Raman signal of targets molecule in the different phase. In situ multiphase detection can minimize the disturbance of sampling and provide more accurate information. The facile fabrication and amphiphilic functionalization make Au-AgN sensor as generalized SERS detection platform for on-site testing of aqueous samples, organic samples, even the multiphase heterogeneous samples

Comparisons of clinical characteristics between pediatric and adult GBS receiving IVIg combined with intravenous corticosteroids.

<p>Comparisons of clinical characteristics between pediatric and adult GBS receiving IVIg combined with intravenous corticosteroids.</p

Comparisons between AMAN and AIDP in children.

<p>The incidence of upper respiratory infection (URI) as antecedent infections of AMAN was 21.7% which was insignificantly different from AIDP (28.6%, <i>p</i> > 0.05). Similarly, the incidence of diarrhea in pediatric AMAN was comparable with AIDP (47.8% vs 42.9%, <i>p</i> > 0.05) (<b>A</b>). The interval from onset to admission was 4.2d in children with AMAN, while it was 6.2d for pediatric AIDP, which was significantly different. However, interval from onset to nadir was comparable between AMAN and AIDP (6.2d vs 7.0d, <i>p</i> > 0.05) (<b>B</b>). The MRC sum score at nadir was lower in pediatric AMAN than childhood AIDP (30.5 ±12.0 vs 39.8±11.0, <i>p</i> < 0.05) (<b>C</b>). AMAN: acute motor axonal neuropathy; AIDP: acute inflammatory demyelinating polyneuropathy; URI: upper respiratory infection; MRC: Medical Research Council.</p

Comparisons of clinical features of AIDP between adults and children.

<p>Comparisons of clinical features of AIDP between adults and children.</p

Comparisons of therapeutic effect of IVIg between children and adults.

<p>Comparisons of therapeutic effect of IVIg between children and adults.</p

Comparisons of the clinical characteristic of mechanically ventilated patients with GBS between adults and children.

<p>Comparisons of the clinical characteristic of mechanically ventilated patients with GBS between adults and children.</p

Seasonal and monthly variation in the occurrence of Guillain-Barré syndrome (GBS).

<p>The incidence of GBS of pediatric patients in spring, summer, autumn and winter was 13.9%, 51.7%, 24.9% and 9.6%, respectively. Accordingly, it was 24.4%, 36.2%, 24.0% and 15.3%, respectively, in the adult ones (<b>A</b>). Further, the monthly variation in the occurrence of GBS was investigated. The incidence of GBS in children and adult during January to December was 2.4% and 7.6%, 3.3% and 2.4%, 3.8% and 7.8%, 2.9% and 7.6%, 7.2% and 9.1%, 8.6% and 10.0%, 23.4% and 16.1%, 19.6% and 10.2%, 10.5% and 8.5%, 6.2% and 8.7%, 8.1% and 6.8%, 3.8% and 5.4%, respectively (<b>B</b>). In addition, the incidence of antecedent infections in spring, summer, autumn and winter was 64.0%, 64.3%, 66.3% and 68.6%, respectively, in adults with GBS; similarly, it was 72.4%, 60.2%, 70.6% and 65%, respectively, in pediatric GBS (<b>C</b>).</p