Biology Engineering Research Articles

Preface for special issue on chemical bioproduction

Engineering efficient enzymes or microbial cell factories should help to establish green bio-manufacturing process for chemical overproduction. The rapid advances and development in synthetic biology, systems biology and enzymatic engineering accerleate the establishing feasbile bioprocess for chemical biosynthesis, including expanding the chemical kingdom and improving the productivity. To consolidate the latest advances in chemical biosynthesis and promote green bio-manufaturing, we organized a special issue on chemical bioproduction that including review or original research papers about enzymatic biosynthesis, cell factory, one-carbon based biorefinery and feasible strategies. These papers comprehensively discussed the latest advaces, the challenges as well as the possible solutions in chemical biomanufacturing.

The Terminal Heat Stress and its Effect on Yield and Yield Contributing Traits of Wheat (Triticum aestivum L.) Genotypes

An experiment was conducted with wheat genotypes NWL-14, K-9162, NWL-1014, NWL-12-2, NWL-12-4, NWL-10-4, K-910-30, NWL-4035, DBW-16, DBW-187, NWL-12 (3) T, Halna, HD-2967 to evaluate heat tolerant in wheat at instructional farm and in the laboratory of Crop Physiology & Plant Molecular Biology and Genetic Engineering, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya, India, during rabi season of 2021-2022. Heat stress was induced by delayed sowing 45 days from normal date of sowing (02 December 2022)-(17 January 2023) so that delay sown wheat genotypes could experience heat stress at reproductive stage. Heat tolerant wheat genotypes screened on the basis of Relative Water Content, Catalase activity, plant height, tiller number, number of grains per spike, test weight and grain yield per plant over control under heat stress condition. Heat stress reduces the the growth and yield irrespective of wheat genotypes but heat tolerant genotypes Halna, NWL-1293)T, NWL 10-2 and NWL-12-4 showed less reduction over susceptible ones. Relative water content, proline and catalase activity can be used as a physiological screening indices for heat tolerant genotypes.

Multi-compartmental MOF microreactors derived from Pickering double emulsions for chemo-enzymatic cascade catalysis

Bioinspired multi-compartment architectures are desired in synthetic biology and metabolic engineering, as credited by their cell-like structures and intrinsic ability of assembling catalytic species for spatiotemporal control over cascade reactions like in living systems. Herein, we describe a general Pickering double emulsion-directed interfacial synthesis method for the fabrication of multicompartmental MOF microreactors. This approach employs multiple liquid–liquid interfaces as a controllable platform for the self-completing growth of dense MOF layers, enabling the microreactor with tailor-made inner architectures and selective permeability. Importantly, simultaneous encapsulation of incompatible functionalities, including hydrophilic enzyme and hydrophobic molecular catalyst, can be realized in a single MOF microreactor for operating chemo-enzymatic cascade reactions. As exemplified by the Grubb’ catalyst/CALB lipase driven olefin metathesis/ transesterification cascade reaction and glucose oxidase (GOx)/Fe-porphyrin catalyzed oxidation reaction, the multicompartmental microreactor exhibits 2.24–5.81 folds enhancement in cascade reaction efficiency in comparison to the homogeneous counterparts or physical mixture of individual analogues, due to the restrained mutual inactivation and substrate channelling effects. Our study prompts further design of multicompartment systems and the development of artificial cells capable of complex cellular transformations.

Polymeric Based Hydrogel Membranes for Biomedical Applications.

The development of biomedical applications is a transdisciplinary field that in recent years has involved researchers from chemistry, pharmacy, medicine, biology, biophysics, and biomechanical engineering. The fabrication of biomedical devices requires the use of biocompatible materials that do not damage living tissues and have some biomechanical characteristics. The use of polymeric membranes, as materials meeting the above-mentioned requirements, has become increasingly popular in recent years, with outstanding results in tissue engineering, for regeneration and replenishment of tissues constituting internal organs, in wound healing dressings, and in the realization of systems for diagnosis and therapy, through the controlled release of active substances. The biomedical application of hydrogel membranes has had little uptake in the past due to the toxicity of cross-linking agents and to the existing limitations regarding gelation under physiological conditions, but now it is proving to be a very promising field This review presents the important technological innovations that the use of membrane hydrogels has promoted, enabling the resolution of recurrent clinical problems, such as post-transplant rejection crises, haemorrhagic crises due to the adhesion of proteins, bacteria, and platelets on biomedical devices in contact with blood, and poor compliance of patients undergoing long-term drug therapies.

Taking Synthetic Biology to the Seas - From Blue Chassis Organisms to Marine Aquaforming.

Oceans cover 71% of Earth's surface and are home to hundreds of thousands of species, many of which are microbial. Knowledge about marine microbes has strongly increased in the past decades due to global sampling expeditions and hundreds of detailed studies on marine microbial ecology, physiology, and biogeochemistry. However, the translation of this knowledge into biotechnological applications or synthetic biology approaches using marine microbes has been limited so far. This review highlights key examples of marine bacteria in synthetic biology and metabolic engineering, and outlines possible future work based on the emerging marine chassis organisms Vibrio natriegens and Halomonas bluephagenesis. Furthermore, the valorization of algal polysaccharides by genetically enhanced microbes is presented as an example for the opportunities and challenges associated with blue biotechnology. Finally, new roles for marine synthetic biology in tackling pressing global challenges, including climate change and marine pollution, are discussed.

Cover Picture: (Mol. Inf. 6/2023)

Molecular InformaticsVolume 42, Issue 6 2380601 Cover PictureFree Access Cover Picture: (Mol. Inf. 6/2023) First published: 22 June 2023 https://doi.org/10.1002/minf.202380601AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Molecular Informatics presents highest-quality interdisciplinary research that leads to a deeper understanding of biomolecular complexes on the level of biological systems that are relevant for drug discovery and chemical biology, protein and nucleic acid engineering and design, bio-nanomolecular structures, macromolecular assemblies, molecular networks and systems, pharmaco- and chemogenomics, virtual screening, and novel technologies for the design of biologically active molecules. Volume42, Issue6June 20232380601 RelatedInformation

Metabolic Engineering and Synthetic Biology Approaches for the Heterologous Production of Aromatic Polyketides.

Polyketides are a diverse set of natural products with versatile applications as pharmaceuticals, nutraceuticals, and cosmetics, to name a few. Of several types of polyketides, aromatic polyketides comprising type II and III polyketides contain many chemicals important for human health such as antibiotics and anticancer agents. Most aromatic polyketides are produced from soil bacteria or plants, which are difficult to engineer and grow slowly in industrial settings. To this end, metabolic engineering and synthetic biology have been employed to efficiently engineer heterologous model microorganisms for enhanced production of important aromatic polyketides. In this review, we discuss the recent advancement in metabolic engineering and synthetic biology strategies for the production of type II and type III polyketides in model microorganisms. Future challenges and prospects of aromatic polyketide biosynthesis by synthetic biology and enzyme engineering approaches are also discussed.

Modulating Sensitivity of an Erythromycin Biosensor for Precise High-Throughput Screening of Strains with Different Characteristics.

Genetically encoded biosensors are powerful tools for product-driven high-throughput screening in synthetic biology and metabolic engineering. However, most biosensors can only properly function in a limited concentration cutoff, and the incompatible performance characteristics of biosensors will lead to false positives or failure in screening. The transcription factor (TF)-based biosensors are usually organized in modular architecture and function in a regulator-depended manner, whose performance properties can be fine-tuned by modifying the expression level of the TF. In this study, we modulated the performance characteristics, including sensitivity and operating range, of an MphR-based erythromycin biosensor by fine-adjusting regulator expression levels via ribosome-binding site (RBS) engineering and obtained a panel of biosensors with varied sensitivities by iterative fluorescence-assisted cell sorting (FACS) in Escherichia coli to accommodate different screening purposes. To exemplify their application potential, two engineered biosensors with 10-fold different sensitivities were employed in the precise high-throughput screening by microfluidic-based fluorescence-activated droplet sorting (FADS) of Saccharopolyspora erythraea mutant libraries with different starting erythromycin productions, and mutants representing as high as 6.8 folds and over 100% of production improvements were obtained starting from the wild-type strain and the high-producing industrial strain, respectively. This work demonstrated a simple strategy to engineer biosensor performance properties, which was significant to stepwise strain engineering and production improvement.

Electro-Responsive Aggregation and Dissolution of Cationic Polymer Using Reversible Redox Reaction of Electron Mediator.

Stimuli-responsive aggregation of polymer chains in water has found a variety of applications in polymer science, biology, and chemical engineering. To date, the majority of the phase transitions between the aggregated and dissolved forms has been observed by changing the solution temperature, and an active and precise control on the phase transition with a high time resolution has been challenging. Herein, a reversible phase transition of poly(allylamine-co-allylurea) (PAU) in an aqueous electrolyte is achieved by electrochemical redox cycling of hexacyanoferrate(II/III) ([Fe(CN)6 ]4-/3- ) ion pair. The aggregation and dissolution cycle can be completed in a high-resolution time frame of as short as 5s. The strong electrostatic interaction between the protonated primary amino group of PAU and the tetravalent [Fe(CN)6 ]4- anion induces the aggregation, while the oxidation to the trivalent [Fe(CN)6 ]3- anion reduces the attractive force, and the polymer chain redissolves in solution. The ureido group of PAU helps the chain-folding process through the formation of inter/intrachain hydrogen-bonding networks, resulting in the sharp phase transition. By using [Fe(CN)6 ]4-/3- as the electron mediator, the electrochemical control on the large transparency change of polymer aqueous solution is realized for the first time.

Spatial Heterogeneity Directs Energy Dissipation in Condylar Fibrocartilage.

Condylar fibrocartilage with structural and compositional heterogeneity can efficiently orchestrate load-bearing and energy dissipation, making the temporomandibular joint (TMJ) survive high occlusion loads for a prolonged lifetime. How the thin condylar fibrocartilage can achieve efficient energy dissipation to cushion enormous stresses remains an open question in biology and tissue engineering. Here,three distinct zones in the condylar fibrocartilage are identified by analyzing the components and structure from the macro-and microscale to the nanoscale. Specific proteinsare highly expressed in each zone related to its mechanics. The heterogeneity of condylar fibrocartilage can direct energy dissipation through the nano-micron-macro gradient spatial scale, by atomic force microscope (AFM), nanoindentation, dynamic mechanical analyzer assay (DMA), and the corresponding energy dissipation mechanismsare exclusive for each distinct zone. This study reveals the significance of the heterogeneity of condylar fibrocartilage in mechanical behavior and provides new insights into the research methods for cartilage biomechanics and the design of energy-dissipative materials.

Preface

International Workshop “Mathematical Modeling and Scientific Computing: Focus on complex processes and systems” (dedicated to the memory of Nikolai Botkin) Munich, October 4-7, 2022 This proceedings volume contains papers presented at the second International Workshop “Mathematical Modeling and Scientific Computing: Focus on complex processes and systems”, MMSC 2022, dedicated to the memory of Nikolai Botkin (22.03.1956–14.09.2019). Nikolai Botkin contributed significantly to mathematical modeling of various physical and biological processes, to the development of numerical methods and algorithms for optimal control of mechanical systems described by ordinary differential equations as well as for complex distributed systems, optimization and nonlinear programming, elasticity theory, hydrodynamics, thermodynamics, and homogenization theory.The first International Workshop MMSC 2020 was held on November 19-20, 2020 at the Technical University of Munich. The proceedings were published with CEUR-WS.org https://ceur-ws.org/Vol-2783/The second workshop MMSC 2022 was held on October 4-7, 2022 at the Technical University of Munich, Germany, in virtual format. Following the scientific interests of Nikolai Botkin, the workshop topics covered mathematical modeling and computer simulation for a wide range of optimal control and trajectory optimization problems, linear and nonlinear programming issues, as well as comprehensive applications in biology, medicine, thermodynamics and aerospace engineering. Recent achievements in machine learning and neural network technologies, challenges in simulation of cerebral blood circulation and bacterial quorum sensing were presented and discussed.In total, 35 invited talks of 77 authors from 12 countries were delivered. Out of 22 papers submitted to Morressier platform, 22 were accepted after peer-review.The editors would like to cordially thank the members of the Program and Organizing Committees, the participants, and the reviewers for actively contributing to the success of MMSC 2022.Editors of the MMSC 2022 ProceedingsVarvara Turova, Andrey Kovtanyuk, Johannes ZimmerList of Program Committee, Organizing Committee are available in this pdf.

Cover Picture: (Mol. Inf. 5/2023)

Molecular InformaticsVolume 42, Issue 5 2380501 Cover PictureFree Access Cover Picture: (Mol. Inf. 5/2023) First published: 11 May 2023 https://doi.org/10.1002/minf.202380501AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Molecular Informatics presents highest-quality interdisciplinary research that leads to a deeper understanding of biomolecular complexes on the level of biological systems that are relevant for drug discovery and chemical biology, protein and nucleic acid engineering and design, bio-nanomolecular structures, macromolecular assemblies, molecular networks and systems, pharmaco- and chemogenomics, virtual screening, and novel technologies for the design of biologically active molecules. Volume42, Issue5May 20232380501 RelatedInformation

Strategies for Engineering Virus Resistance in Potato.

Potato (Solanum tuberosum L.) is an important vegetable crop that plays a pivotal role in the world, especially given its potential to feed the world population and to act as the major staple food in many developing countries. Every year, significant crop loss is caused by viral diseases due to a lack of effective agrochemical treatments, since only transmission by insect vectors can be combated with the use of insecticides, and this has been an important factor hindering potato production. With the rapid development of molecular biology and plant genetic engineering technology, transgenic approaches and non-transgenic techniques (RNA interference and CRISPR-cas9) have been effectively employed to improve potato protection against devastating viruses. Moreover, the availability of viral sequences, potato genome sequences, and host immune mechanisms has remarkably facilitated potato genetic engineering. In this study, we summarize the progress of antiviral strategies applied in potato through engineering either virus-derived or plant-derived genes. These recent molecular insights into engineering approaches provide the necessary framework to develop viral resistance in potato in order to provide durable and broad-spectrum protection against important viral diseases of solanaceous crops.

3D quantitative assessment for nuclear morphology in osteocytic spheroid with optical clearing technique.

In recent years, three-dimensional (3D) cell culture has been attracting attention as a cell culture model that mimics an environment closer to that of a living organism. It is known that there is a close relationship between cell nuclear shape and cellular function, which highlights the importance of cell nucleus shape analysis in the 3D culture. On the other hand, it is difficult to observe the cell nuclei inside the 3D culture models because the penetration depth of the laser light under a microscope is limited. In this study, we adopted an aqueous iodixanol solution to the 3D osteocytic spheroids derived from mouse osteoblast precursor cells to make the spheroids transparent for 3D quantitative analysis. With a custom-made image analysis pipeline in Python, we found that the aspect ratio of the cell nuclei near the surface of the spheroid was significantly greater than that at the center, suggesting that the nuclei on the surface were deformed more than those at the center. The results also quantitatively showed that the orientation of nuclei in the center of the spheroid was randomly distributed, whereas those on the surface of the spheroid were oriented parallel to the surface of the spheroid. Our 3D quantitative method with an optical clearing technique will contribute to the 3D culture models including various organoid models to elucidate the nuclear deformation during the development of the organs. Insight box Although 3D cell culture has been a powerful tool in the fields of fundamental biology and tissue engineering, it raises the demand for quantification techniques for cell nuclear morphology in the 3D culture model. In this study, we attempted to optically clear a 3D osteocytic spheroid model using iodixanol solution for the nuclear observation inside the spheroid. Moreover, using a custom-made image analysis pipeline in Python, we successfully quantified the nuclear morphology regarding aspect ratio and orientation. Our quantitative method with the optical clearing technique will contribute to the 3D culture models such as various organoid models to elucidate the nuclear deformation during the development of the organs.

L-lactate production in engineered Saccharomyces cerevisiae using a multistage multiobjective automated design framework.

The design of alternative biodegradable polymers has the potential of severely reducing the environmental impact, cost and production time currently associated with the petrochemical industry. In fact, growing demand for renewable feedstock has recently brought to the fore synthetic biology and metabolic engineering. These two interdependent research areas focus on the study of microbial conversion of organic acids, with the aim of replacing their petrochemical-derived equivalents with more sustainable and efficient processes. The particular case of Lactic acid (LA) production has been the subject of extensive research because of its role as an essential component for developing an eco-friendly biodegradable plastic-widely used in industrial biotechnological applications. Because of its resistance to acidic environments, among the many LA-producing microbes, Saccharomyces cerevisiae has been the main focus of research into related biocatalysts. In this study, we present an extensive in silico investigation of S. cerevisiae cell metabolism (modeled with Flux Balance Analysis) with the overall aim of maximizing its LA production yield. We focus on the yeast 8.3 steady-state metabolic model and analyze it under the impact of different engineering strategies including: gene knock-in, gene knock-out, gene regulation and medium optimization; as well as a comparison between results in aerobic and anaerobic conditions. We designed ad-hoc constrained multiobjective evolutionary algorithms to automate the engineering process and developed a specific postprocessing methodology to analyze the genetic manipulation results obtained. The in silico results reported in this paper empirically show that our method is able to automatically select a small number of promising genetic and metabolic manipulations, deriving competitive strains that promise to impact microorganisms design in the production of sustainable chemicals.

Structure-driven protein engineering for production of valuable natural products.

Proteins are the most frequently used biocatalysts, and their structures determine their functions. Modifying the functions of proteins on the basis of their structures lies at the heart of protein engineering, opening a new horizon for metabolic engineering by efficiently generating stable enzymes. Many attempts at classical metabolic engineering have focused on improving specific metabolic fluxes and producing more valuable natural products by increasing gene expression levels and enzyme concentrations. However, most naturally occurring enzymes show limitations, and such limitations have hindered practical applications. Here we review recent advances in protein engineering in synthetic biology, chemoenzymatic synthesis, and plant metabolic engineering and describe opportunities for designing and constructing novel enzymes or proteins with desirable properties to obtain more active natural products.

Cover Picture: (Mol. Inf. 4/2023)

Molecular InformaticsVolume 42, Issue 4 2380401 Cover PictureFree Access Cover Picture: (Mol. Inf. 4/2023) First published: 12 April 2023 https://doi.org/10.1002/minf.202380401AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Molecular Informatics presents highest-quality interdisciplinary research that leads to a deeper understanding of biomolecular complexes on the level of biological systems that are relevant for drug discovery and chemical biology, protein and nucleic acid engineering and design, bio-nanomolecular structures, macromolecular assemblies, molecular networks and systems, pharmaco- and chemogenomics, virtual screening, and novel technologies for the design of biologically active molecules. Volume42, Issue4April 20232380401 RelatedInformation

Bone Marrow Mesenchymal Stem Cells Expanded Inside the Nichoid Micro-Scaffold: a Focus on Anti-Inflammatory Response

PurposeMesenchymal stem cells (MSCs) represent a promising source for stem cell therapies in numerous diseases, including pediatric respiratory system diseases. Characterized by low immunogenicity, high anti-inflammatory, and immunoregulatory features, MSCs demonstrated an excellent therapeutic profile in numerous in vitro and preclinical models. MSCs reside in a specialized physiologic microenvironment, characterized by a unique combination of biophysical, biochemical, and cellular properties. The exploitation of the 3D micro-scaffold Nichoid, which simulates the native niche, enhanced the anti-inflammatory potential of stem cells through mechanical stimulation only, overcoming the limitation of biochemical and xenogenic growth factors application.Materials and MethodsIn this work, we expanded pediatric bone marrow MSCs (BM-MSCs) inside the Nichoid and performed a complete cellular characterization with different approaches including viability assays, immunofluorescence analyses, RNA sequencing, and gene expression analysis.ResultsWe demonstrated that BM-MSCs inside the scaffold remain in a stem cell quiescent state mimicking the condition of the in vivo environment. Moreover, the gene expression profile of these cells shows a significant up-regulation of genes involved in immune response when compared with the flat control.ConclusionThe significant changes in the expression profile of anti-inflammatory genes could potentiate the therapeutic effect of BM-MSCs, encouraging the possible clinical translation for the treatment of pediatric congenital and acquired pulmonary disorders, including post-COVID lung manifestations.Lay SummaryRegenerative medicine is the research field integrating medicine, biology, and biomedical engineering. In this context, stem cells, which are a fundamental cell source able to regenerate tissues and restore damage in the body, are the key component for a regenerative therapeutic approach. When expanded outside the body, stem cells tend to differentiate spontaneously and lose regenerative potential due to external stimuli. For this reason, we exploit the scaffold named Nichoid, which mimics the in vivo cell niche architecture. In this scaffold, mesenchymal stem cells “feel at home” due to the three-dimensional mechanical stimuli, and our findings could be considered as an innovative culture system for the in vitro expansion of stem cells for clinical translation.Future PerspectiveThe increasing demand of safe and effective cell therapies projects our findings toward the possibility of improving cell therapies based on the use of BM-MSCs, particularly for their clinical translation in lung diseases.Graphical

Engineering Escherichia coli to Utilize Erythritol as Sole Carbon Source.

Erythritol, one of the natural sugar alcohols, is widely used as a sugar substitute sweetener in food industries. Humans themselves are not able to catabolize erythritol and their gut microbes lack related catabolic pathways either to metabolize erythritol. Here, Escherichia coli (E. coli) is engineered to utilize erythritol as sole carbon source aiming for defined applications. First, the erythritol metabolic gene cluster is isolated and the erythritol-binding transcriptional repressor and its DNA-binding site are experimentally characterized. Transcriptome analysis suggests that carbohydrate metabolism-related genes in the engineered E. coli are overall upregulated. In particular, the enzymes of transaldolase (talA and talB) and transketolase (tktA and tktB) are notably overexpressed (e.g., the expression of tktB is improved by nearly sixfold). By overexpression of the four genes, cell growth can be increased as high as threetimes compared to the cell cultivation without overexpression. Finally, engineered E. coli strains can be used as a living detector to distinguish erythritol-containing soda soft drinks and can grow in the simulated intestinal fluid supplemented with erythritol. This work is expected to inspire the engineering of more hosts to respond and utilize erythritol for broad applications in metabolic engineering, synthetic biology, and biomedical engineering.

Optical Characteristics of Silver Nanoparticles Obtained Using Artemisia tilesii Ledeb. "Hairy" Root Extracts With High Flavonoid Content

Background. "Hairy" roots can be used for production of plant-derived secondary metabolites, such as flavonoids, which have antioxidant and reducing properties. It seems promising to use the process of silver nanoparticles formation as a method of determining the level of reducing power. This approach allows simul­taneously to obtain nanoparticles with different biological activity and evaluate the reducing potential of dif­ferent plants. Objective. The aim of the study was to determine the dependence of optical properties (ultraviolet/visible spectroscopy, UV-Vis spectra) of solutions of silver nanoparticles obtained using wormwood "hairy" root extracts on the content of flavonoids as compounds with reducing activity. Methods. Four Artemisia tilesii “hairy” root lines from the collection of the Institute of Cell Biology and Genetic Engineering NAS of Ukraine were grown for five weeks in liquid 1/2 MS medium with 20 g/l sucrose. "Hairy" roots were homogenized in 70% ethanol, the extracts were centrifuged, total flavonoid content was determined, and extracts were used for the silver nanoparticles preparation via reduction of Ag+ to Ag0 from AgNO3. UV-Vis spectra at 300–600 nm range were recorded right after colloid solution preparation, in five, and in nine days. Results. Total flavonoid content varied from 4.01 ± 0.39 to 15.37 ± 1.08 mg RE/g FW. The UV-Vis spectra curves of absorption increased with the course of time, mostly from day 0 to day 5. At this period, absorption at 370–500 nm wavelength increased almost twofold. The peak absorption of all samples was detected at 440 nm, and the maximum values at the wavelength of 440 nm correlated with the content of flavonoids. This correlation did not change over time. Conclusions. The optical properties of silver nanoparticles colloid solutions obtained using A. tilesii "hairy" root extracts correlated with the total flavonoid content of the samples. Even though the absorbance of the colloid solutions increased with time, those increases correlated with flavonoid content as well. The determination of the optical properties of AgNPs colloid solution can be used as a convenient way of quickly comparing the reducing ability of extracts both right after the formation of a colloidal solution and after some time of its storage.