Gelatin nanoparticles found numerous applications in drug delivery, bioimaging, immunotherapy, and vaccine development as well as in biotechnology and food science. Synthesis of gelatin nanoparticles is usually made by a two-step desolvation method, which, despite providing stable and homogeneous nanoparticles, has many limitations, namely complex procedure, low yields, and poor reproducibility of the first desolvation step. Herein, we present a modified one-step desolvation method, which enables the quick, simple, and reproducible synthesis of gelatin nanoparticles. Using the proposed method one can prepare gelatin nanoparticles from any type of gelatin with any bloom number, even with the lowest ones, which remains unattainable for the traditional two-step technique. The method relies on quick one-time addition of poor solvent (preferably isopropyl alcohol) to gelatin solution in the absence of stirring. We applied the modified desolvation method to synthesize nanoparticles from porcine, bovine, and fish gelatin with bloom values from 62 to 225 on the hundreds-of-milligram scale. Synthesized nanoparticles had average diameters between 130 and 190 nm and narrow size distribution. Yields of synthesis were 62–82% and can be further increased. Gelatin nanoparticles have good colloidal stability and withstand autoclaving. Moreover, they were non-toxic to human immune cells.

1H-Pyrrole-2,3-diones, fused at [e]-side with a heterocycle, are suitable platforms for the synthesis of various angular polycyclic alkaloid-like spiroheterocycles. Recently discovered sulfur-containing [e]-fused 1H-pyrrole-2,3-diones (aroylpyrrolobenzothiazinetriones) tend to exhibit unusual reactivity. Based on these peculiar representatives of [e]-fused 1H-pyrrole-2,3-diones, we have developed an approach to an unprecedented 6/5/5/5-tetracyclic alkaloid-like spiroheterocyclic system of benzo[d]pyrrolo[3′,4′:2,3]pyrrolo[2,1-b]thiazole via their reaction with Schiff bases and carbodiimides. The experimental results have been supplemented with DFT computational studies. The synthesized alkaloid-like 6/5/5/5-tetracyclic compounds have been tested for their biotechnological potential as growth stimulants in the green algae Chlorella vulgaris.

Chlorella vulgaris, a unicellular microalga with broad industrial applications, is a valuable source of bioactive compounds, including proteins, pigments, and lipids. However, optimizing its growth and metabolite production remains a challenge. This study investigates the potential of angular 6/6/5/6-annelated pyrrolidine-2,3-diones—structurally complex small molecules resembling alkaloids and 13(14 → 8)abeo-steroids—as novel growth stimulants for C. vulgaris. A series of these compounds (20 structurally diverse derivatives, including 7 previously unreported ones) were synthesized and screened for their ability to enhance microalgal growth. Primary screening identified one compound as a promising candidate, significantly increasing algae cell concentration in microplate cultures. Subsequent validation in flask-scale experiments revealed that this candidate induced a 19% increase in protein content at 1 μmol/L, suggesting potential for protein enrichment in algal biomass. Stability studies of the candidate compound revealed its significant hydrolytic degradation in aqueous media. These findings highlight the potential of angular 6/6/5/6-annelated pyrrolidine-2,3-diones as modulators of microalgal metabolism, offering a new avenue for enhancing C. vulgaris biomass quality, particularly for protein-rich applications in the food and feed industries.

Acylpyruvate derivatives represent a promising yet underexplored class of compounds for modulating microalgal growth and metabolism. Inspired by the metabolic role of pyruvate and the diverse bioactivity of its acylated analogs, this study investigates the structure–activity relationship of a diverse library of 55 acylpyruvate-derived compounds for stimulation of the green microalga Chlorella vulgaris. The library, encompassing 12 chemotypes including acylpyruvic acids, their esters, and various heterocyclic derivatives, was screened for effects on C. vulgaris growth. Six compounds were identified as active ones that enhanced biomass production in a preliminary microassay. Notably, four of these active compounds were direct acylpyruvate derivatives, highlighting this scaffold as the most promising one. Conversely, a specific subclass, 1,4-benzoxazin-2-ones, exhibited potent, dose-dependent algicidal activity. Detailed assessment of the active compounds under scaled-up culture conditions revealed that while their effect on overall cell density was limited, several compounds significantly enhanced the intracellular content of valuable metabolites: one increased chlorophyll content by 17%, another elevated carotenoids by 40%, and a third boosted neutral lipid accumulation by 44%. Furthermore, control experiments confirmed that the bioactivity of p-ethoxybenzoylpyruvates, which showed the best biological activity, is inherent in the intact framework and is not mediated by their hydrolysis products. Our findings underscore the potential of acylpyruvates as versatile tools for the enhancement of metabolite production in microalgae and as potent candidates for the development of algicides.

3,3',5,5'-Tetramethylbenzidine (TMB) remains one of the most widely utilized chromogenic substrates for horseradish peroxidase (HRP) in colorimetric immunoassays, including enzyme-linked immunosorbent assays (ELISA). Despite its introduction into ELISA workflows over four decades ago, limited research has been conducted to systematically optimize TMB substrate formulations. Recent advancements in the field have proposed innovative approaches to enhance HRP catalysis, such as the use of deep eutectic solvents and ionic liquids, alongside investigations into the chemical properties of TMB and its analogs to identify more efficient alternatives. However, the development of stable and high-performance TMB solutions for clinical diagnostics requires a comprehensive understanding of how formulation parameters influence signal intensity and stability. In this study, we address these gaps by conducting a systematic evaluation of key factors affecting TMB substrate performance, including buffer pH, composition and molarity, specific ion effects, incorporation of organic solvents, and the use of polymer stabilizers. Additionally, novel strategies for signal amplification, identified through an extensive review of literature and patents, were experimentally tested. Based on these findings, we developed an optimized TMB formulation that was benchmarked against existing formulations reported in the literature.

Микроводоросли, и в частности Chlorella vulgaris, на данный момент являются важнейшими инструментами современного технологического производства различных продуктов и товаров. За последние десятилетия область применения микроводорослей заметно расширилась и нет сомнений, что технологии на основе микроводорослей будут развиваться и находить новые применения. Создание возобновляемого топливного сырья из C. vulgaris, по оценкам экспертов, поможет преодолеть экономические и технические проблемы, связанные с сокращением запасов нефти. Большое пространство для улучшения данных технологий остаётся в области поиска новых способов стимулирования как физических (освещение, магнитные поля, температура), так и химических (фитогормоны, удобрения, малые органические молекулы). В этой обзорной работе будут рассмотрены перспективы применения C. vulgaris в промышленности, а также способы увеличения ее биомассы и содержания полезных метаболитов.