Chemistry and Biochemistry (Progyateg Chakma)
Photo-Responsive Solid-State Reactions Through Crystalline Peptoid Assemblies
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Organic nanomaterials are highly desirable because of their high stability, robustness, morphological diversity, and high crystallinity. In the field of crystal engineering, there are significant aspects, as tunable molecular arrangements in organic nanomaterials allow for the modulation of intra- and intermolecular interactions, leading to advanced materials with tailored functionalities. In particular, the formation of covalent bonds via solid-state reactions offers unique advantages, including enhanced reactivity and regional and stereospecificity, which might be difficult to access through conventional organic synthetic methods. However, the primary challenge in performing a solid-state reaction is to properly align the reactive molecules in a specific orientation with a proximal distance, which is challenging to realize and control. We aim to utilize the assembly of sequence-defined peptoids into highly crystalline nanomaterials to address this challenge.
Polypeptoids are a novel class of synthetic polymers that share a similar backbone structure with polypeptides, but with the side chain attached to the nitrogen atom instead of the 伪-carbon. This subtle modification enhances flexibility, resistance to proteolysis, and stability, while maintaining biocompatibility and ordered folding behavior akin to that of polypeptides. Polypeptoids serve as a link between biological polymers and synthetic polymers, providing opportunities to create sequence-programmable, folded polymers with the durability of synthetic materials, leading to different applications such as antimicrobial agents, diagnostic agents, drug delivery, and bio-separation.
Interestingly, amphiphilic peptoids can be self-assembled into highly crystalline nanosheets, nanoribbons, and nanotubes with a backbone-to-backbone distance of 4.5 脜 along the x direction. This is very significant, as per Schmidt鈥檚 rule, as for efficient solid-state 2+2 photodimerization, the distance between the carbon-carbon double bonds should be approximately 4.2 脜. Based on this principle, we aim to design a series of amphiphilic peptoids functionalized with photo-responsive molecules, which can self-assemble into highly crystalline nanomaterials and initiate highly efficient 2+2 solid-state photodimerization. Peptoids will be synthesized using a highly efficient solid-phase synthesis methodology, purified by preparative high-performance liquid chromatography (HPLC), and characterized by liquid chromatography-tandem mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy. The self-assembly of the purified peptoids will be performed using a facile slow evaporation method, and characterization will be carried out using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Finally, 2+2 photodimerization will be performed using a photoreactor, and efficiency will be characterized by NMR and UV-Vis spectroscopy. The long-term goal of this project is to develop dynamic materials with applications in catalysis.
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Students involved in this program will gain hands-on interdisciplinary research experience in basic organic synthesis, peptoid synthesis, and materials chemistry. In addition to performing research, students will gain expertise in data collection and analysis, scientific writing, and public presentations at conferences and symposiums. They will be trained in instruments such as liquid chromatography, mass spectrometry, NMR spectroscopy, UV-Vis spectroscopy, and electron microscopy, which will be highly beneficial for them to pursue advanced degrees, such as Master's or PhDs, in materials science, biochemistry, polymer chemistry, chemical engineering, and biomedical science. Additionally, expertise in these methodologies and characterization techniques will be vital in securing industrial positions in fields such as pharmaceuticals, biomedical, and adhesive industries. |
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Students will be involved in various duties weekly in different stages of the project, including 鈥 1) reading and reviewing of scientific literature, 2) take part in group meetings, 3) synthesis and characterization of peptoids, 4) self-assembly of peptoids into nanomaterials and their characterization, 5) proper data collection and critical analysis, 6) drafting of posters, involvement in manuscript writing, and giving presentations. |
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Modality (Face-to-Face, Hybrid, Online)
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