The crystal types of nanoparticles (NPs) are governed by many factors, such as temperature, pH, solvents, surface ligands, etc. In this work, β-HgS and α-HgS NPs coated with captopril (Cap) have been synthesized conveniently in the same raw materials and similar methods just with different temperature at 4 °C and 50 °C, respectively. More interestingly, phase transition of HgS NPs from β-crystal (cubic crystal) to α-crystal (hexagonal crystal) via rising temperature from 4 to 50 °C was confirmed by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The size of α-HgS NPs grew to 6.7±1.3 nm in the process of phase transition, which was about twice of β-HgS NPs (3.5±1.0 nm). Furthermore, compared with the obvious absorption peak of β-HgS NPs at 688 nm, the absorption peak of α-HgS NPs had a giant blue-shifted to 470 nm in Ultraviolet and visible (UV-vis) spectra. In addition, the β-HgS NPs had a fluorescence emission at 900 nm differing from α-HgS NPs without emission. The α-HgS NPs had three peaks at 215 nm, 251 nm and 318 nm, while the β-HgS NPs had only a distinct peak at 215 nm in circular dichroism (CD) spectra. These results provide a novel insight for the controlling preparation of different crystal types of nanoparticles.

Using DNA as the next-generation medium for data storage offers unparalleled advantages in terms of data density, storage duration, and power consumption as compared to existing data storage technologies. To meet the high-speed data writing requirements in DNA data storage, this paper proposes a novel design for an ultra-high-density and high-throughput DNA synthesis platform. The presented design mainly leverages two functional modules: a dynamic random-access memory (DRAM)-like integrated circuit (IC) responsible for electrode addressing and voltage supply, and the static droplet array (SDA)-based microfluidic structure to eliminate any reaction species diffusion concern in electrochemical DNA synthesis. Through theoretical analysis and simulation studies, we validate the effective addressing of 10 million electrodes and stable, adjustable voltage supply by the integrated circuit. We also demonstrate a reaction unit size down to 3.16 × 3.16 μm², equivalent to 10 million/cm², that can rapidly and stably generate static droplets at each site, effectively constraining proton diffusion. Finally, we conducted a synthesis cycle experiment by incorporating fluorescent beacons on a microfabricated electrode array to examine the feasibility of our design.