POLYseq: A poly(β-amino ester)-based vector for multifunctional cellular barcoding.

Despite evolving biological application of next-generation sequencing (NGS) at single-cell level, current techniques in NGS library preparation restrict multiplexing, necessitating the costly preparation of distinct libraries for each sample. Here, we report the development of a novel poly(β-amino) ester labeling system synthesized with inexpensive, common reagents, termed POLYseq, capable of efficiently delivering fluorescent molecules or sample-distinguishing DNA barcodes through non-covalent binding enabling rapid creation of custom sample pools. Chemical formulation was found to determine cellular labeling propensity. Live image-based tracking of fluorescent conjugated POLYseq vectors demonstrated lysosomal compartmentalization. Barcode labeling was uniformly detected across 90% of cells by single-cell RNA sequencing, allowing for the successful identification of human and mouse cultured cell lines from a single pool. These findings highlight the multifunctional applications of POLYseq in live cell imaging and NGS in a scalable and cost-effective manner.