Bioprospecting solid binding polypeptides for lithium ion battery cathode materials

Identification of Microorganisms that Bind Specifically to Target Materials of Interest Using a Magnetophoretic Microfluidic Platform

Discovery of microorganisms and their relevant surface peptides that specifically bind to target materials of interest can be achieved through iterative biopanning-based screening of cellular libraries having high diversity. Recently, microfluidics-based biopanning methods have been developed and exploited to overcome the limitations of conventional methods where controlling the shear stress applied to remove cells that do not bind or only weakly bind to target surfaces is difficult and the overall experimental procedure is labor-intensive. Despite the advantages of such microfluidic methods and successful demonstration of their utility, these methods still require several rounds of iterative biopanning. In this work, a magnetophoretic microfluidic biopanning platform was developed to isolate microorganisms that bind to target materials of interest, which is gold in this case. To achieve this, gold-coated magnetic nanobeads, which only attached to microorganisms that exhibit high affinity to gold, were used. The platform was first utilized to screen a bacterial peptide display library, where only the cells with surface peptides that specifically bind to gold could be isolated by the high-gradient magnetic field generated within the microchannel, resulting in enrichment and isolation of many isolates with high affinity and high specificity toward gold even after only a single round of separation. The amino acid profile of the resulting isolates was analyzed to provide a better understanding of the distinctive attributes of peptides that contribute to their specific material-binding capabilities. Next, the microfluidic system was utilized to screen soil microbes, a rich source of extremely diverse microorganisms, successfully isolating many naturally occurring microorganisms that show strong and specific binding to gold. The results show that the developed microfluidic platform is a powerful screening tool for identifying microorganisms that specifically bind to a target material surface of interest, which can greatly accelerate the development of new peptide-driven biological materials and hybrid organic-inorganic materials.

Bio-Templating: An Emerging Synthetic Technique for Catalysts. A Review

In the last few years, researchers have focused their attention on the synthesis of new catalyst structures based on or inspired by nature. Biotemplating involves the transfer of biological structures to inorganic materials through artificial mineralization processes. This approach offers the main advantage of allowing morphological control of the product, as a template with the desired morphology can be pre-determined, as long as it is found in nature. This way, natural evolution through millions of years can provide us with new synthetic pathways to develop some novel functional materials with advantageous properties, such as sophistication, miniaturization, hybridization, hierarchical organization, resistance, and adaptability to the required need. The field of application of these materials is very wide, covering nanomedicine, energy capture and storage, sensors, biocompatible materials, adsorbents, and catalysis. In the latter case, bio-inspired materials can be applied as catalysts requiring different types of active sites (i.e., redox, acidic, basic sites, or a combination of them) to a wide range of processes, including conventional thermal catalysis, photocatalysis, or electrocatalysis, among others. This review aims to cover current experimental studies in the field of biotemplating materials synthesis and their characterization, focusing on their application in heterogeneous catalysis.