Cross-Platform Bayesian Optimization System for Autonomous Biological Assay Development

Current high-throughput screening assay optimization is often a manual and time-consuming process, even when utilizing design-of-experiment approaches. A cross-platform, Cloud-based Bayesian optimization-based algorithm was developed as part of the National Center for Advancing Translational Sciences (NCATS) ASPIRE (A Specialized Platform for Innovative Research Exploration) Initiative to accelerate preclinical drug discovery. A cell-free assay for papain enzymatic activity was used as proof of concept for biological assay development and system operationalization. Compared with a brute-force approach that sequentially tested all 294 assay conditions to find the global optimum, the Bayesian optimization algorithm could find suitable conditions for optimal assay performance by testing 21 assay conditions on average, with up to 20 conditions being tested simultaneously, as confirmed by repeated simulation. The algorithm could achieve a sevenfold reduction in costs for lab supplies and high-throughput experimentation runtime, all while being controlled from a remote site through a secure connection. Based on this proof of concept, this technology is expected to be applied to more complex biological assays and automated chemistry reaction screening at NCATS, and should be transferable to other institutions. Graphical Abstract

Comparison between In Vitro Chemical and Ex Vivo Biological Assays to Evaluate Antioxidant Capacity of Botanical Extracts

The anti-oxidative activity of plant-derived extracts is well-known and confers health-promoting effects on functional foods and food supplements. Aim of this work is to evaluate the capability of two different assays to predict the real biological antioxidant efficiency. At this purpose, extracts from five different plant-derived matrices and commercial purified phytochemicals were analyzed for their anti-oxidative properties by using well-standardized in vitro chemical method (TEAC) and an ex vivo biological assay. The biological assay, a cellular membrane system obtained from erythrocytes of healthy volunteers, is based on the capability of phytochemicals treatment to prevent membrane lipid peroxidation under oxidative stress by UV-B radiation. Plant extracts naturally rich in phenols with different structure and purified phytochemicals showed different in vitro and ex vivo antioxidant capacities. A high correlation between phenolic contents of the plant-derived extracts and their ability to prevent oxidative injuries in a biological system was found, thus underlying the relevance of this class of metabolites in preventing oxidative stress. On the other hand, a low correlation between the antioxidant capacities was shown between in vitro and ex vivo antioxidant assay. Moreover, data presented in this work show how food complex matrices are more effective in preventing oxidative damages at biological level than pure phytochemicals, even if for these latter, the antioxidant activity was generally higher than that observed for food complex matrices.

Challenges and Perspectives for Biosensing of Bioaerosol Containing Pathogenic Microorganisms

As an important route for disease transmission, bioaerosols have received increasing attention. In the past decades, many efforts were made to facilitate the development of bioaerosol monitoring; however, there are still some important challenges in bioaerosol collection and detection. Thus, recent advances in bioaerosol collection (such as sedimentation, filtration, centrifugation, impaction, impingement, and microfluidics) and detection methods (such as culture, molecular biological assay, and immunological assay) were summarized in this review. Besides, the important challenges and perspectives for bioaerosol biosensing were also discussed.