Volume 36, Issue 4

In recent decades, there has been a substantial increase in the consumption of fruits and vegetables due to their nutritional properties since they are known as sources of vitamins, minerals, fiber, and antioxidants. Moreover, a substantial growth in fresh-cut fruits and vegetables has been noticed because of their ease to use; in fact changes in human life styles have led consumers to move towards ready-to-eat products. In this context, product quality must be preserved at each step of product handling, processing, and storage, and therefore rapid methods should be available to provide useful information in process management. In this review an overview of the applications of widely used non-destructive techniques, namely, electronic nose and visible/near infrared spectroscopy, for measuring quality of fruits and vegetables is presented. A brief description of spectroscopic and electronic devices and a selection of applications are provided. Future perspectives about the simplification/application of these non-destructive techniques are finally explored.

The attractive structural and mechanical properties of cellulose substrates (paper, cloth, and thread), including passive fluid transport, biocompatibility, durability, and flexibility, have attracted researchers in the past few decades to explore them as alternative microfluidic platforms. The incorporation of electrochemical (EC) sensing broadened their use for applications such as clinical diagnosis, pharmaceutical chemical analyses, food quality, and environmental monitoring. This article provides a review on the microfluidic devices constructed on paper, cloth, and thread substrates. It begins with an overview on paper-based microfluidic devices, followed by an in-depth review on the various applications of EC detection incorporated on paper-based microfluidic devices reported to date. The review on paper-based microfluidic devices attempts to convey a few perspective directions that cloth- and thread-based microfluidic devices may take in its development. Finally, the research efforts on the development and evaluation, as well as current limitations of cloth- and thread-based microfluidic devices are discussed. Microfluidic devices constructed on paper, cloth, and thread substrates are still at an early development stage (prototype) requiring several improvements in terms of fabrication, analytical techniques, and performance to become mature platforms that can be adapted and commercialized as real world products. However, they hold a promising potential as wearable devices.

Surface-enhanced Raman scattering (SERS) has become a powerful technique for trace analysis of biomolecules. The use of SERS-tags has evolved into clinical diagnostics; the enhancement of the intrinsic signal of biomolecules on SERS active materials shows tremendous promise for the analysis of biomolecules and potential biomedical assays. The detection of the de novo signal from a wide range of biomolecules has been reported to date. In this review, we examine different classes of biomolecules for the signals observed and experimental details that enable their detection. In particular, we survey nucleic acids, amino acids, peptides, proteins, metabolites, and pathogens. The signals observed show that the interaction of the biomolecule with the enhancing nanostructure has a significant influence on the observed spectrum. Additional experiments demonstrate that internal standards can correct for intensity fluctuations and provide quantitative analysis. Experimental methods that control the interaction at the surface are providing for reproducible SERS signals. Results suggest that combining advances in methodology with the development of libraries for SERS spectra may enable the characterization of biomolecules complementary to other existing methods.