Information, such as text printed on paper or images projected onto microfilm, can survive for over 500 years. However, the storage of digital information for time frames exceeding 50 years is challenging. Here we show that digital information can be stored on DNA and recovered without errors for considerably longer time frames. To allow for the perfect recovery of the information, we encapsulate the DNA in an inorganic matrix, and employ error-correcting codes to correct storage-related errors. Specifically, we translated 83 kB of information to 4991 DNA segments, each 158 nucleotides long, which were encapsulated in silica. Accelerated aging experiments were performed to measure DNA decay kinetics, which show that data can be archived on DNA for millennia under a wide range of conditions. The original information could be recovered error free, even after treating the DNA in silica at 70 8C for one week. This is thermally equivalent to storing information on DNA in central Europe for 2000 years.Prehistorical information put down by our ancestors in cave drawings, texts engraved in gold, and medieval texts are some of the strongest links with our past. An example is the Archimedes Palimpsest that originates from the tenth century. This contains the single known copy of "The Methods of Mechanical Theorems", and represents a cornerstone in the development of geometry and modern calculus. The book has survived more than 1000 years and in 1998 was valued at more than two million USD. In view of this valuation of information it may seem surprising that current efforts of guaranteeing longevity of digital information are scarce (e.g. MDisc, Syylex) and the storage half-life of information has dropped drastically since the transition from analog to digital storage systems.[1]Traditional storage technologies such as optical and magnetic devices are not reliable for long-term (> 50 years) data storage.[2] Furthermore, the development of reliable systems requires long-term testing, which is well above the current device-development timelines. DNA is the only datastorage medium for which real long-term data are available from archeology. Most recently, 300 000 year old mitochondrial DNA from bears and humans has been sequenced. [3] DNA has also previously been utilized as a coding language, for applications in forensics, [4] product tagging, [5] and DNA computing.[6] As a consequence, several approaches to store information on DNA have been proposed. [7] However, those approaches are not reliable as they cannot handle errors efficiently and do not suggest how to (physically) store the DNA to maintain its stability over time.To overcome these issues we combined an error-correcting information-encoding scheme tailored to DNA (Scheme 1) with a previously established chemical method for storing DNA in "synthetic fossils". The corresponding experiments show that only by the combination of the two concepts, could digital information be recovered from DNA stored at the Global Seed Vault (at À18 8C) after over 1 milli...

This protocol describes a method for encapsulating DNA into amorphous silica (glass) spheres, mimicking the protection of nucleic acids within ancient fossils. In this approach, DNA encapsulation is achieved after the ammonium functionalization of silica nanoparticles. Within the glass spheres, the nucleic acid molecules are hermetically sealed and protected from chemical attack, thereby withstanding high temperatures and aggressive radical oxygen species (ROS). The encapsulates can be used as inert taggants to trace chemical and biological entities. The present protocol is applicable to short double-stranded (ds) and single-stranded (ss) DNA fragments, genomic DNA and plasmids. The nucleic acids can be recovered from the glass spheres without harm by using fluoride-containing buffered oxide etch solutions. Special emphasis is placed in this protocol on the safe handling of these buffered hydrogen fluoride solutions. After dissolution of the spheres and subsequent purification, the nucleic acids can be analyzed by standard techniques (gel electrophoresis, quantitative PCR (qPCR) and sequencing). The protocol requires 6 d for completion with a total hands-on time of 4 h.

A method to encapsulate DNA in heat-resistant and inert magnetic particles was developed. An inexpensive synthesis technique based on co-precipitation was utilized to produce Fe2O3 nanoparticles, which were further functionalized with ammonium groups. DNA was adsorbed on this magnetic support, and the DNA/magnet nanocluster was surface coated with a dense silica layer by sol-gel chemistry. The materials were further surface modified with hexyltrimethoxysilane to achieve particle dispersibility in hydrophobic liquids. The hydrodynamic particle sizes were evaluated by analytical disc centrifugation, and the magnetic properties were investigated by vibrating sample magnetometry. The obtained nanoengineered encapsulates showed good dispersion abilities in various nonaqueous fluids and did not affect the optical properties of the hydrophobic dispersant when present at concentrations lower than 10(3) μg/L. Upon magnetic separation and particle dissolution, the DNA could be recovered unharmed and was analyzed by quantitative real-time PCR and Sanger sequencing. DNA encapsulated within the magnetic particles was stable for 2 years in decalin at room temperature, and the stability was further tested at elevated temperatures. The new magnetic DNA/silica encapsulates were utilized to developed a low-cost platform for the tracing/tagging of oils and oil-derived products, requiring 1 μg/L=1 ppb levels of the taggant and allowing quantification of taggant concentration on a logarithmic scale. The procedure was tested for the barcoding of a fuel (gasoline), a cosmetic oil (bergamot oil), and a food grade oil (extra virgin olive oil), being able to verify the authenticity of the products.

Environmental tracing is a direct way to characterize aquifers, evaluate the solute transfer parameter in underground reservoirs, and track contamination. By performing multitracer tests, and translating the tracer breakthrough times into tomographic maps, key parameters such as a reservoir's effective porosity and permeability field may be obtained. DNA, with its modular design, allows the generation of a virtually unlimited number of distinguishable tracers. To overcome the insufficient DNA stability due to microbial activity, heat, and chemical stress, we present a method to encapsulated DNA into silica with control over the particle size. The reliability of DNA quantification is improved by the sample preservation with NaN 3 and particle redispersion strategies. In both sand column and unconsolidated aquifer experiments, DNA-based particle tracers exhibited slightly earlier and sharper breakthrough than the traditional solute tracer uranine. The reason behind this observation is the size exclusion effect, whereby larger tracer particles are excluded from small pores, and are therefore transported with higher average velocity, which is pore size-dependent. Identical surface properties, and thus flow behavior, makes the new material an attractive tracer to characterize sandy groundwater reservoirs or to track multiple sources of contaminants with high spatial resolution.