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The increasing incidence of fraud demands for new robust methods to assess food authenticity. Over the past decades, biosensors have emerged as practical testing devices with exponential growth in diverse research fields. Their numerous advantages have contributed to their implementation in the food sector, with applications ranging from the identification of pathogens, chemical compounds and allergens to spoilage detection and Genetically Modified Organisms (GMO) identification in various food products. This review explores the development of DNA-based biosensors for food authenticity assessment with a focus on species identification. The role and versatility of nucleic acids as analytes and biorecognition elements are discussed, and the available conventional methods are presented. The main transducing principles involved in biosensing, and the use of nanomaterials are briefly introduced. The application of various DNA-based biosensors over the last decade is shown, highlighting the main innovations and how these have contributed to the improvement of their performance. The final section addresses how different technologies can influence biosensor manufacturing and optimization, so these can become established rapid on-site testing devices used to assess food authenticity. In the food sector, little research has been carried out in food authenticity regarding biosensors. The development of these devices is mainly aimed at species identification in meat and derived products, although other equally relevant products should be targeted. Several recent technological advances have been successfully integrated into biosensors and must be further explored to promote the establishment of these devices in food authenticity assessment. • DNA biosensors for food authenticity focused on species identification are explored. • The potential of DNA as biorecognition element and analyte is discussed. • Different biosensors are presented to show progress from the last decade. • New technological advances are being implemented into improved DNA biosensors. • DNA biosensors to authenticate high value food items are currently lacking. [ABSTRACT FROM AUTHOR]

Highlights • Label-free DNA-based biosensor applied to authenticity. • Varietal identification in different matrices (leaf, must and wine samples) • PCR-free detection. Abstract The diversity found among the Vitis vinifera L. species allows the production of wines with very different characteristics. The development of platforms suitable for food composition analysis is currently an emerging area. Among these, DNA biosensors have been developed for a wide variety of applications, ranging from food safety to authenticity. The main aim of this work was to study the detection capacity of the DNA-based optical biosensor using different V. vinifera matrices (leaf, must and wine). Genomic DNA was extracted from leaf, must and wine of three V. vinifera varieties and was tested on the long-period grating (LPG) DNA-based biosensor developed within our group. The biosensor was able to distinguish the varieties even using DNA extracted from complex matrices, revealing its potential to be applied in wine authenticity. [ABSTRACT FROM AUTHOR]

Lung cancer is the main malignant cancer reported worldwide, with one of the lowest survival rates. Deletions in the Epidermal Growth Factor Receptor (EGFR) gene are often associated with non-small cell lung cancer (NSCLC), a common subtype of lung cancer. The detection of such mutations provides key information for the diagnosis and treatment of the disease; therefore, the early screening of such biomarkers is of vital importance. The need for fast, reliable, and early detection means applied to NSCLC has led to the development of highly sensitive devices that can detect cancer-associated mutations. Such devices, known as biosensors, are a promising alternative to more conventional detection methods and can potentially alter the way cancer is diagnosed and treated. In this study, we report the development of a DNA-based biosensor, namely a quartz crystal microbalance (QCM), applied to the detection of NSCLC, from liquid biopsies samples. The detection, as is the case of most DNA biosensors, is based on the hybridization between the NSCLC-specific probe and the sample DNA (containing specific mutations associated with NSCLC). The surface functionalization was performed with a blocking agent (dithiothreitol) and thiolated-ssDNA strands. The biosensor was able to detect specific DNA sequences in both synthetic and real samples. Aspects such as reutilization and regeneration of the QCM electrode were also studied. [Display omitted] • DNA based QCM biosensor applied to Non-Small Cell Lung Cancer. • Detection from cfDNA present in plasma. • Detection of EGFR deletion in exon 19. [ABSTRACT FROM AUTHOR]

The ability to detect and quantify small amounts of DNA in biological complex samples is a hot research area. Up until recently most of the work performed in this area used label-dependent protocols that increases its complexity and overall costs. The aim the work was to develop a label-free technology suitable for DNA detection and quantification using real complex DNA samples. The applicability of this system was tested using synthetic ssDNA targets that guaranteed the systems specificity, in the sense that only complementary sequences hybridized with the probe. When using real samples extracted from Vitis vinifera L. the system was able to successfully detect and quantify the DNA present without any of the time consuming and costly amplification steps. The detection and quantification limits of the proposed system were 60 ± 20 nM and 201 ± 20 nM, respectively for Target 1 concentrations between 31 and 350 nM. This method can easily be applied to other species and purposes, allowing the direct detection of DNA in a label-free environment with high accuracy and specificity. [ABSTRACT FROM AUTHOR]

A label-free fiber optic biosensor based on a long period grating (LPG) and a basic optical interrogation scheme using off the shelf components is used for the detection of in-situ DNA hybridization. A new methodology is proposed for the determination of the spectral position of the LPG mode resonance. The experimental limit of detection obtained for the DNA was 62±2 nM and the limit of quantification was 209±7 nM. The sample specificity was experimentally demonstrated using DNA targets with different base mismatches relatively to the probe and was found that the system has a single base mismatch selectivity. [ABSTRACT FROM AUTHOR]