DNA storage in thermoresponsive microcapsules for repeated random multiplexed data access.

DNA has emerged as an attractive medium for archival data storage due to its durability and high information density. Scalable parallel random access to information is a desirable property of any storage system. For DNA-based storage systems, however, this still needs to be robustly established. Here we report on a thermoconfined polymerase chain reaction, which enables multiplexed, repeated random access to compartmentalized DNA files. The strategy is based on localizing biotin-functionalized oligonucleotides inside thermoresponsive, semipermeable microcapsules. At low temperatures, microcapsules are permeable to enzymes, primers and amplified products, whereas at high temperatures, membrane collapse prevents molecular crosstalk during amplification. Our data show that the platform outperforms non-compartmentalized DNA storage compared with repeated random access and reduces amplification bias tenfold during multiplex polymerase chain reaction. Using fluorescent sorting, we also demonstrate sample pooling and data retrieval by microcapsule barcoding. Therefore, the thermoresponsive microcapsule technology offers a scalable, sequence-agnostic approach for repeated random access to archival DNA files.

Impact of poly(ethylene glycol) functionalized lipids on ordering and fluidity of colloid supported lipid bilayers.

Colloid supported lipid bilayers (CSLBs) are highly appealing building blocks for functional colloids. In this contribution, we critically evaluate the impact on lipid ordering and CSLB fluidity of inserted additives. We focus on poly(ethylene glycol) (PEG) bearing lipids, which are commonly introduced to promote colloidal stability. We investigate whether their effect on the CSLB is related to the incorporated amount and chemical nature of the lipid anchor. To this end, CSLBs were prepared from lipids with a low or high melting temperature (Tm), DOPC, and DPPC, respectively. Samples were supplemented with either 0, 5 or 10 mol% of either a low or high Tm PEGylated lipid, DOPE-PEG2000 or DSPE-PEG2000, respectively. Lipid ordering was probed via differential scanning calorimetry and fluidity by fluorescence recovery after photobleaching. We find that up to 5 mol% of either PEGylated lipids could be incorporated into both membranes without any pronounced effects. However, the fluorescence recovery of the liquid-like DOPC membrane was markedly decelerated upon incorporating 10 mol% of either PEGylated lipids, whilst insertion of the anchoring lipids (DOPE and DSPE without PEG2000) had no detectable impact. Therefore, we conclude that the amount of incorporated PEG stabilizer, not the chemical nature of the lipid anchor, should be tuned carefully to achieve sufficient colloidal stability without compromising the membrane dynamics. These findings offer guidance for the experimental design of studies using CSLBs, such as those focusing on the consequences of intra- and inter-particle inhomogeneities for multivalent binding and the impact of additive mobility on superselectivity.

Fractal-like R5 assembly promote the condensation of silicic acid into silica particles.

HYPOTHESIS: Despite advances in understanding the R5 (SSKKSGSYSGKSGSKRRIL) peptide-driven bio-silica process, there remains significant discrepancies regarding the physicochemical characterization and the self-assembling mechanistic driving forces of the supramolecular R5 template. This paper investigates the self-assembly of R5 as a function of monovalent (sodium chloride) and multivalent salt (phosphate) to determine if assembly is phosphate ion concentration dependent. Additionally, we hypothesize that the assembled R5 aggregates do not resemble a micelle or unimer structure as proposed in current literature. EXPERIMENTS: R5 peptides were synthesized, and aggregates evaluated for their size, morphology, and association state as a function of salt and ionic strength concentration via dynamic and static light scattering, small angle X-ray and neutron scattering and cryogenic transmission electron microscopy. Furthermore, we compare the proposed R5 template to precipitated silica by scanning electron microscopy. FINDINGS: R5 peptides assemble into large aggregates due to multivalence bridging and the decrease in electrostatic repulsion due to ionic strength. We elucidate the structure of R5 aggregates as mass-fractals composed of small spherical aggregates. Moreover, we discover that phosphate ions not only have a significant role in driving the growth of the R5 scaffold, but additionally in driving the polycondensation of silicic acid during the bio-silification process via electrostatic interactions.

Bioinspired Scaffolding by Supramolecular Amines Allows the Formation of One- and Two-Dimensional Silica Superstructures.

Silica materials attract an increasing amount of interest in (fundamental) research, and find applications in, for example, sensing, catalysis, and drug delivery. As the properties of these (nano)materials not only depend on their chemistry but also their size, shape, and surface area, the controllable synthesis of silica is essential for tailoring the materials to specific applications. Advantageously, bioinspired routes for silica production are environmentally friendly and straightforward since the formation process is spontaneous and proceeds under mild conditions. These strategies mostly employ amine-bearing phosphorylated (bio)polymers. In this work, we expand this principle to supramolecular polymers based on the water-soluble cationic cyanine dye Pinacyanol acetate. Upon assembly in water, these dye molecules form large, polyaminated, supramolecular fibers. The surfaces of these fibers can be used as a scaffold for the condensation of silicic acid. Control over the ionic strength, dye concentration, and silicic acid saturation yielded silica fibers with a diameter of 25 nm and a single, 4 nm pore. Unexpectedly, other unusual superstructures, namely, nummulites and spherulites, are also observed depending on the ionic strength and dye concentration. Transmission and scanning electron microscopy (TEM and SEM) showed that these superstructures are formed by aligned silica fibers. Close examination of the dye scaffold prior silicification using small-angle X-ray scattering (SAXS), and UV/Vis spectroscopy revealed minor influence of the ionic strength and dye concentration on the morphology of the supramolecular scaffold. Total internal reflection fluorescence (TIRF) during silicification unraveled that if the reaction is kept under static conditions, only silica fibers are obtained. Experiments performed on the dye scaffold and silica superstructures evidenced that the marked structural diversity originates from the arrangement of silica/dye fibers. Under these mild conditions, external force fields can profoundly influence the morphology of the produced silica.