The quality of food is one of the emergent points worldwide. Many microorganisms produce toxins that are harmful for human and animal health. In particular, mycotoxins from Fusarium fungi are strictly controlled in cereals. Simple and robust biosensors are necessary for ‘in field’ control of the crops and processed products. Nucleic acid-based sensors (aptasensors) offer a new era of point-of-care devices with excellent stability and limits of detection for a variety of analytes. Here we report the development of a surface-enhanced Raman spectroscopy (SERS)-based aptasensor for the detection of T-2 and deoxynivalenol in wheat grains. The aptasensor was able to detect as low as 0.17% of pathogen fungi in the wheat grains. The portable devices, inexpensive SERS substrate, and short analysis time encourage further implementation of the aptasensors outside of highly equipped laboratories.
Anhydrofusarubin is a naphthoquinone pigment synthesized by a number of Fusarium genus fungi. Being a biologically active substance, it demonstrates promising antibiotic properties and rather good hypothetical effectiveness against certain types of cancer. In this regard, an important task arises to study the structural properties and spectral manifestation of Anhydrofusarubin in order to identify and characterize this substance in terms of synthesis and application purposes. In this regard, the aim of the article was to study the structure of the Anhydrofusarubin molecule and its structure-property correlation. The density functional theory was used to investigate the optical properties and stability of the molecular structures. The computational results obtained with B3LYP and wb97XD exchange correlation functionals and the triple zeta basis sets were compared with available experimental data. In addition to the ground state structure, a tautomer with slightly higher energy (by 0.78–0.9 kcal/mol) and a relatively small potential barrier was found. Also, the investigation of flexibility of the pyran ring reveals the presence of two conformational enantiomer forms, being in good agreement with the recent experimental data on the crystal structure. The vibrational and UV-visible absorption spectra were simulated and interpreted.
We present an in-depth analysis of Raman spectra of novel block copolymers of methyl ethylene phosphate (MeOEP) with caprolactone (CL) and L-lactide (LA), recorded with the excitation wavelengths of 532 and 785 nm. The experimental peak positions, relative intensities and profiles of the poly(methyl ethylene phosphate) (PMeOEP), polycaprolactone (PCL) and poly(L-lactide) (PLA) bands in the spectra of the copolymers and in the spectra of the PMeOEP, PCL and PLA homopolymers turn out to be very similar. This clearly indicates the similarity between the conformational and phase compositions of PMeOEP, PCL and PLA parts in molecules of the copolymers and in the PMeOEP, PCL and PLA homopolymers. Experimental ratios of the peak intensities of PMeOEP bands at 737 and 2963 cm−1 and the PCL bands at 1109, 1724 and 2918 cm−1 can be used for the estimation of the PCL—b—PMeOEP copolymers chemical composition. Even though only one sample of the PMeOEP—b—PLA copolymers was experimentally studied in this work, we assume that the ratios of the peak intensities of PLA bands at 402, 874 and 1768 cm−1 and the PMeOEP band at 737 cm−1 can be used to characterize the copolymer chemical composition.