A Molecular-imprinted Sensor for Trace Detection of Gibberellin Based on Ferrocenecarboxylic Acid Multiply Marked Dendrimer

An ultrasensitive probe-free electrochemical immunosensor for gibberellins employing polydopamine-antibody nanoparticles modified electrode

Gibberellins (GA₃) is an ubiquitous plant hormone, which plays a regulatory role in different growth stages of plants, so it is of great significance to develop a sensitive quantitative analysis method for GA₃. In this study, carboxylated graphene oxide- carboxylated multi-walled carbon nanotubes-Fc (GO-MWNT-Fc) composite material and PDANPs-antibody (PDANPs-Ab) were sequentially modified to screen-printed electrodes (SPEs), and an ultrasensitive probe-free immunosensor for GA₃ was developed. Fc was applied to generate electrochemical signals. GO-COOH and MWNT-COOH can increase the catalytic ability of the sensor and bind the PDANPs-Ab nanoparticles. PDANPs nanomaterial were synthetized by a facile self-polymerization and used to bind with antibody, so as to increase the antibody loading of the sensor. The as-prepared immunosensor has the widest detection range (100 aM-1 mM) and lowest detection limit (17.4 aM) for GA₃ up to date. To our knowledge, it is the first electrochemical immunosensor for GA₃. By changing the GA₃ antibody to ABA antibody, a sensitive and selective immunosensor for ABA was also fabricated. This immunosensor platform is simple, sensitive, and low cost. It opens broad prospect in on-site applications for biosensors in detecting of various biomolecules in precision agriculture.

Current State of Sensors and Sensing Systems Utilized in Beer Analysis

Beer is one of the most consumed beverages in the world. Advances in instrumental techniques have allowed the analysis and characterization of a large number of beers. However, review studies that outline the methodologies used in beer characterization are scarce. Herein, a systematic review investigating the molecular targets and sensometric techniques in beer characterization was performed following the PRISMA protocol. The study reviewed 270 articles related to beer analysis in order to provide a comprehensive summary of the recent advances in beer analysis, including methods using sensors and sensing systems. The results revealed the use of various techniques that include several technologies, such as nanotechnology and electronics, often combined with scientific data analysis tools. To our knowledge, this study is the first of its kind and provides the reader with a faithful overview of what has been done in the sensor field regarding beer characterization.

Zooming In on Plant Hormone Analysis: Tissue- and Cell-Specific Approaches

Plant hormones are a group of naturally occurring, low-abundance organic compounds that influence physiological processes in plants. Our knowledge of the distribution profiles of phytohormones in plant organs, tissues, and cells is still incomplete, but advances in mass spectrometry have enabled significant progress in tissue- and cell-type-specific analyses of phytohormones over the last decade. Mass spectrometry is able to simultaneously identify and quantify hormones and their related substances. Biosensors, on the other hand, offer continuous monitoring; can visualize local distributions and real-time quantification; and, in the case of genetically encoded biosensors, are noninvasive. Thus, biosensors offer additional, complementary technologies for determining temporal and spatial changes in phytohormone concentrations. In this review, we focus on recent advances in mass spectrometry-based quantification, describe monitoring systems based on biosensors, and discuss validations of the various methods before looking ahead at future developments for both approaches.