Periplasmic biomineralization of semiconductors and semiconductor alloys for living photosensitive biomaterials

NON-TECHNICAL SUMMARY:

The periplasm, a confined space inside bacteria, could be used as a platform for new technologies that combine bacteria with semiconductors. These biohybrid systems could have many uses, such as large-scale chemical production and controlling bacterial activities without changing their genetics. By adding light-sensitive semiconductor particles to the periplasm, chemical production can be increased by affecting key processes in bacteria.

This approach uses the natural structures of bacteria and different combinations of semiconductor particles to advance microbial engineering. The principal investigator is developing methods to grow semiconductor particles within the periplasm in cells to study how they interact with bacteria. The goal is to design experiments that mimic photosynthesis to increase chemical production, for example in the production of malate, a valuable chemical precursor.

This project will also provide valuable learning opportunities for students from diverse backgrounds. By offering interdisciplinary research experiences and international exchange programs, the project will increase diversity in science and engineering. Educational initiatives will include summer research opportunities for high school and undergraduate students, particularly those from underrepresented groups, as well as international symposia and partnerships with local art centers.

The results will be shared widely through publications, seminars, conferences, and online platforms. TECHNICAL SUMMARY:

The periplasmic space in bacteria offers a unique environment for creating semiconductor-based biointerfaces, which can be used for large-scale biosynthesis and modulation of bacterial processes without genetic modifications. Incorporating light-harvesting semiconductor nanoclusters into the periplasm can significantly enhance the efficiency of chemical production in biohybrid systems by modulating central metabolic processes.

This approach leverages existing cellular structures and diverse nanocluster-cell combinations to innovate microbial engineering. The principal investigator aims to establish a robust protocol for biomineralizing semiconductor nanoclusters and their alloys within the periplasm. The study will probe the biomineralization mechanisms and the properties of the resulting biointerfaces using transcriptome, proteome, metabolome, and fluxome analyses to identify the molecular pathways and potential stress conditions involved.

The optical properties of the semiconductor/bacteria composites will be examined with fluorescence microscopy and micro-spectrofluorometry, while transient absorption and time-resolved infrared spectroscopy will probe energy and charge transfer mechanisms at the biointerfaces. The research ultimately aims to conduct artificial photosynthesis experiments using a custom-built light emitting diode array for illumination and differential pulse voltammetry to measure chemical production, with a focus on improving malate bioproduction yield through a scalable bioreactor process.

This research will also provide valuable interdisciplinary learning opportunities and foster diversity in science and engineering through summer research experiences, international exchanges, and educational programs for high school and undergraduate students. The outcomes will be disseminated through publications, seminars, conferences, and online platforms.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.