Photonic microspheres for high-capacity DNA data storage: Robust, straightforward, and scalable random access via nonfading indexes

DNA-based storage offers a compelling alternative to traditional optical and magnetic devices. However, random data access usually requires additional noncoding primer DNA as indexes, which substantially reduce the physical data density. Here, we propose an alternative strategy to overcome this barrier by loading different data-encoding DNA files into porous microspheres, each distinguished by unique photonic bandgaps and diameters, allowing for 10⁵ types of indexing. With the two features as the addressing indexes, the physical separation of subsets from a diverse pool of DNA files is achieved, thereby facilitating the selective retrieval of stored data. The interconnected nanopore arrays and uniformly distributed positive charges within the microspheres enhance DNA enrichment, achieving a storage density of up to 22.6 exabytes per gram, far exceeding that of previous random access storage methods. This work outlines a simple and scalable method for creating nonfading photonic indexes, enabling long-term random access while maintaining high storage capacity.