π-Conjugated organic semiconductors have been explored in several optoelectronic devices, yet their use in molecular detection as surface-enhanced Raman spectroscopy (SERS)-active platforms is unknown. Herein, we demonstrate that SERS-active, superhydrophobic and ivy-like nanostructured films of a molecular semiconductor, α,ω-diperfluorohexylquaterthiophene (DFH-4T), can be easily fabricated by vapour deposition. DFH-4T films without any additional plasmonic layer exhibit unprecedented Raman signal enhancements up to 3.4 × 10 for the probe molecule methylene blue. The combination of quantum mechanical computations, comparative experiments with a fluorocarbon-free α,ω-dihexylquaterthiophene (DH-4T), and thin-film microstructural analysis demonstrates the fundamental roles of the π-conjugated core fluorocarbon substitution and the unique DFH-4T film morphology governing the SERS response. Furthermore, Raman signal enhancements up to ∼10 and sub-zeptomole (<10 mole) analyte detection were accomplished by coating the DFH-4T films with a thin gold layer. Our results offer important guidance for the molecular design of SERS-active organic semiconductors and easily fabricable SERS platforms for ultrasensitive trace analysis.

The utilization of inorganic semiconductors for surface‐enhanced Raman spectroscopy (SERS) has attracted enormous interest. However, despite the technological relevance of organic semiconductors for enabling inexpensive, large‐area, and flexible devices via solution processing techniques, these π‐conjugated systems have never been investigated for SERS applications. Here for the first time, a simple and versatile approach is demonstrated for the fabrication of novel SERS platforms based on micro‐/nanostructured 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene (C8‐BTBT) thin films via an oblique‐angle vapor deposition. The morphology of C8‐BTBT thin films is manipulated by varying the deposition angle, thus achieving highly favorable 3D vertically aligned ribbon‐like micro‐/nanostructures for a 90° deposition angle. By combining C8‐BTBT semiconductor films with a nanoscopic thin Au layer, remarkable SERS responses are achieved in terms of enhancement (≈108), stability (>90 d), and reproducibility (RSD < 0.14), indicating the great promise of Au/C8‐BTBT films as SERS platforms. Our results demonstrate the first example of an organic semiconductor‐based SERS platform with excellent detection characteristics, indicating that π‐conjugated organic semiconductors have a great potential for SERS applications.

In this report, we present a paper membrane-based surface-enhanced Raman scattering (SERS) platform for the determination of blood glucose level using a nitrocellulose membrane as substrate paper, and the microfluidic channel was simply constructed by wax-printing method. The rod-shaped gold nanorod particles were modified with 4-mercaptophenylboronic acid (4-MBA) and 1-decanethiol (1-DT) molecules and used as embedded SERS probe for paper-based microfluidics. The SERS measurement area was simply constructed by dropping gold nanoparticles on nitrocellulose membrane, and the blood sample was dropped on the membrane hydrophilic channel. While the blood cells and proteins were held on nitrocellulose membrane, glucose molecules were moved through the channel toward the SERS measurement area. Scanning electron microscopy (SEM) was used to confirm the effective separation of blood matrix, and total analysis is completed in 5 min. In SERS measurements, the intensity of the band at 1070 cm(-1) which is attributed to B-OH vibration decreased depending on the rise in glucose concentration in the blood sample. The glucose concentration was found to be 5.43 ± 0.51 mM in the reference blood sample by using a calibration equation, and the certified value for glucose was 6.17 ± 0.11 mM. The recovery of the glucose in the reference blood sample was about 88 %. According to these results, the developed paper-based microfluidic SERS platform has been found to be suitable for use for the detection of glucose in blood samples without any pretreatment procedure. We believe that paper-based microfluidic systems may provide a wide field of usage for paper-based applications.

A simple approach for the fabrication of plasmonic nanoparticle-containing multilayer films using a bio-inspired polydopamine coating was demonstrated.

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Background and objectives Tea fiber is a co‐product of black tea production. It is a cheap and good source of fiber and polyphenols. In this study, the impact of finely ground tea fiber addition (2.5, 5.0, 7.5, and 10.0%) on wheat dough and bread was evaluated. Findings Tea fiber contained 8.39% moisture, 15.65% protein, 1.58% fat, 3.63% ash, 17,289 mg GAE/kg tea fiber phenolic, and 67.62% total dietary fiber. The addition of tea fiber (2.5%, 5.0%, 7.5%, and 10.0%) decreased dough stability and extensibility, index of swelling, baking strength, loaf volume, and specific volume while increased dough development time, water absorption, dough tenacity, configuration ratio, the degree of dough softening and firmness. The baking loss of bread made with tea fibers and control were not significantly different. Crumb characteristics were similar to control loaf, except bread with 10.0% tea fiber added. The control, bread with 2.5% and 5.0% had the same sensory parameters. Conclusion In bread making, 2.5% of tea fiber can be recommended as a fiber‐enriching agent. Significance and novelty This paper shows the characterization of tea fiber and its effect on wheat flour and dough.

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