Research On Long-term Storage Of Biological Information Based On Biosilicification Strategy

Gene,a general term for specific nucleotide sequences with genetic effects on deoxyribonucleic acid(DNA)molecules,is the genetic unit that stores information in nucleic acid,controls the synthesis of various proteins and the operation in organisms,which is the basis of heredity and material continuation.In 1985,"Human Genome Project" was first proposed by American scientists,aiming at deciphering all human genetic information and enabling human beings to fully understand themselves at the molecular level.With the completion of the human genome project,the role of genes in the fields of disease treatment,new drug development,genetic disease diagnosis,individual identification and criminal investigation has become more and more significant.However,gene is fragile and degradable as the material carrier of biological information.It is of great significance at the national level to develop new technologies to achieve its stable,long-term and low-cost preservation,and to expand the existing mode of preservation of genetic information and the construction of gene banks.Biosilicification,namely the formation of biological structures composed of silica,is ubiquitous in nature(such as diatoms,etc.),and is also widely used to construct organicinorganic composite materials.Through the selection of siloxane precursors and the precise control of hydrolysis-condensation conditions,this technology can effectively imitate the formation of fossils in nature.The human body is composed of 40-60 trillion cells,most of which have nuclei,containing 3 billion DNA base pairs,which are ideal gene storage carriers.By simulating fossil formation in nature,the cells are processed to accelerate the formation of "cell fossils",making it possible to achieve in situ encapsulation and long-term storage of genomes in cells.In this paper,aiming at the long-term storage of genome in cells,by regulating the entry mechanism of siloxane precursors,in-depth investigating on the interaction mode of inorganic materials with cells and internal genomes,and establishing an "in situ encapsulation,on-demand extraction" intracellular,the concept of genome storage is expected to develop a new paradigm for the storage of biological information(genome,transcriptome and proteome).The specific research contents include:1.We developed the " cryosilicification " technology,with the assistance of ice crystals,which allows the silica precursor to diffuse into cells and nuclei in a dormant state.The precursor is then hydrolyzed and condensed under the catalysis of cell proteins,and deposited into the whole cell in the form of amorphous silica,realizing the complete encapsulation of intracellular DNA.Different from the traditional formaldehyde preservation mode,the cryosilicification technology will not cause damage and fragmentation to DNA,ensuring the integrity of the genome in cells.The complete packaging of the genome in the cell can not only greatly improve the resistance of the cell genome to extreme conditions(such as ultraviolet light,high temperature and oxygen free radicals,etc.),but also greatly extend the storage life of the whole blood genome.Studies have shown that the half-life of genome storage after treatment at 20 °C is about 1208 years,and the stability is increased by 167 times compared with unprotected blood samples.This technology is low-cost,highly scalable,and easy to combine with different media,such as paper-based carriers or 3D printing technology,thereby greatly expanding the application scenarios of the technology.2.We developed the "deep-silicification" technology,which enables the silica precursor to improve the penetration and intracellular deposition of inorganic silicon elements at room temperature with the assistance of a small amount of permeable solvent dimethyl sulfoxide(DMSO),thereby improving the encapsulation effect of inorganic materials on cells.Studies have shown that with the assistance of the permeable small molecule DMSO,the deposition of siloxane precursors in cells is 30 times that of the original " cryosilicification " technology,namely 27.2 pg/cell.After accelerated aging for 1 day,gel electrophoresis showed that deepsilicification samples had the same bright and clear DNA bands as fresh cell samples,while DNA bands in formaldehyde-fixed samples were almost invisible.deep-silicified samples could still fully amplify all target genome fragments even after accelerated aging for 21 days.The development of " deep-silicification " technology at room temperature avoids the need for low temperature and makes it more convenient in application.3.We developed the "targeted-silicification" technology,through the rational design of the molecular structure,endowing the siloxane precursor with the behavior of targeting the mitochondria,combining with the " cryosilicification " technology,realizing the spatial precision of the mitochondrial DNA(mt DNA)in the cell encapsulation.Studies have shown that the " targeted-silicification " technology is feasible and enables rapid encapsulation of mt DNA in a short period of time.Similarly,after accelerated aging,unprotected samples lost their characteristic DNA bands within 7 days,while the targeted-silicified sample still maintained stable and visible DNA bands.The intact packaging of mitochondria in the cell greatly improves the resistance of mt DNA to extreme conditions(such as ultraviolet light,high temperature and oxygen free radicals,etc.).The spatiotemporal precise encapsulation and long-term storage of intracellular DNA provides multi-dimensional information related to time and space,and plays a positive role in promoting the understanding of the occurrence and development of gene-related diseases.This research developed the cell genome storage concept of "in situ encapsulation,ondemand extraction",through the in-depth understanding of the cell entry mechanism of inorganic siloxane precursors at the molecular level,and the precise regulation of inorganic materials and action of cells and intracellular DNA in different dimensions of time and space.We established an accelerated aging model,based on intracellular genome storage,revealing the changing rules of DNA structure under accelerated aging or extreme conditions,thus forming a relatively complete "molecular rational design-cell entry mechanism research-cell and material composite regulation-DNA structure changing rules analysis" system,which promoted the practical application of new technologies in the field of gene banks.