US 9,938,520 B2  20  19  particles, the nucleic acid binding capacity and ways to  determine it, and the composition of the silica particles  regarding the comprised SiO$_{2 }$ and core particles are  described above and it is referred to the above disclosure  which also applies here. Non-limiting embodiments are  again briefly described in the following.  According to one embodiment, the silica particles are  capable of binding at least 12.5 µg nucleic acid molecules  per mg particles, at least 15 µg nucleic acid molecules per  mg particles or at least 17 .5 µg nucleic acid molecules per  mg particles. As is shown by the examples, the silica  particles of the present invention are even capable of binding  at least 20 µg nucleic acid molecules per mg particles. This  extraordinary high nucleic acid binding capacity is an  important advantage over prior art silica particles. As  described above, according to one embodiment, the nucleic  acid binding capacity of the particles is determined as  described in example 6.  The porous silica particles may comprise macropores.  According to one embodiment, the surface of the particles  additionally comprises micropores. Micro- and macropores  can be determined as described by IUPAC (see above).  According to one embodiment, the particles have a size of  25 µm  or less, 20 µm  or less, 15 µm  or less, 10 µm  or less,  5  µm  or less or 3 µm  or less. Suitable size ranges are also  described above. The silica particles may have a size that lies  within the range of 50 nm to 25 µm, 100 nm to 10 µm, 100  nm to 5 µm  or 250 nm to 3 µm.  According to one embodiment, the porous silica particles  have a composition regarding the comprised SiO$_{2 }$ and core  particles that is 20 to 50% (by weight) core particles and  about 50 to 80% (by weight) SiO$_{2}$ ,  preferably 25 to 50% (by  weight) core particles and about 50 to 75% (by weight) SiO$_{2 }$ (see also above). According to one embodiment, the silica  particles have an unmodified silica surface.  According to one embodiment, the contained core par› ticles have magnetic properties. E.g. the core particles may  have superparamagnetic, paramagnetic, ferromagnetic or  ferrimagnetic properties. Suitable materials were described  in detail above. According to one embodiment, the particles  comprise iron oxide, preferably magnetite and/or maghemite  as core particles. According to one embodiment, the core  particles, which preferably are magnetic, have a diameter  that lies in a range selected from 8 to 150 nm, 10 to 100 nm  and 10 nm to 60 nm.  As described, the silica particles according to the second  aspect are obtainable by the method according to the first  aspect. Details with respect to said method according to the  first aspect are described above, and it is referred to the  above disclosure. The particles are due to their high nucleic  acid binding capacity preferably used for isolating nucleic  acids.  Use of the Particles  According to a third aspect, the present disclosure per› tains to the use of silica particles produced according to the  method according to the first aspect or the use of silica  particles according to the second aspect, for isolating  biomolecules, in particular for isolating nucleic acids from  various samples.  The particles produced with the method according to the  present invention as well as the particles according to the  second aspect can be used basically in all fields in particular  all fields of life science, including but not limited to the  isolation of biomolecules, biological materials such as cells  or cell organelles, analytical, forensic, diagnostic or medical  applications.  The silica particles obtained by the method according to  the present invention have a high capacity to bind biomol› ecules such nucleic acids, thereby making the particles of  this invention especially useful for isolating or separating  biomolecules such as nucleic acid molecules from various  samples and mixtures. The biomolecule to be isolated may  be selected from the group consisting of nucleic acids,  proteins, polypeptides, peptides, carbohydrates, lipids, and  combinations thereof. In particular, the particles produced  according to the present invention are suitable for isolating  nucleic acids.  Subsequently, the use of the particles produced by the  method of the invention for isolating nucleic acids from  samples will be described in further detail. The term  "sample" in this respect is used in a broad sense and is  intended to include a variety of sources that contain nucleic  acids. The sample may be a biological sample but the term  also includes other, e.g. artificial samples which comprise  nucleic acids such as in vitro reaction mixtures that contain  nucleic acids, such as polymerase chain reactions (PCR),  nucleic acid sequencing reactions, restriction endonuclease  or other nuclease digestion reactions, nucleic acid hybrid› ization assay mixture, in vitro transcription and/or transla- tion assay mixtures and amplification reactions. Preferably,  the sample is a biological sample. Exemplary biological  samples include, but are not limited to, tissues, including but  not limited to, liver, spleen, kidney, lung, intestine, brain,  heart, muscle, fat, pancreas, cells, cell cultures, body fluids  in general; whole blood; serum; plasma; red blood cells;  white blood cells; buffy coat, tumor cells, fetal cells, host  and graft cells; swabs, including but not limited to buccal  swabs, throat swabs, vaginal swabs, urethral swabs, cervical  swabs, throat swabs, rectal swabs, lesion swabs, abscess  swabs, nasopharyngeal swabs, and the like; urine; sputum;  saliva; semen; lymphatic fluid; liquor; anmiotic fluid; cere› brospinal fluid; peritoneal effusions; pleural effusions; fluid  from cysts; synovial fluid; vitreous humor; aqueous humor;  bursa fluid; eye washes; eye aspirates; pulmonary lavage;  lung aspirates; bone marrow aspirates, cells in suspension,  as well as lysates, extracts, or materials obtained from any  cells and microorganisms and viruses that may be present on  or in a sample and the like. Materials obtained from clinical  or forensic settings that contain nucleic acids are also within  the intended meaning of the term biological sample. Fur› thermore, the skilled artisan will appreciate that lysates,  extracts, or materials or portions thereof obtained from any  of the above exemplary samples are also within the scope of  the term sample. Preferably, the sample is a biological  sample derived from a human, animal, plant, bacteria or  fungi. It may be of prokaryotic or eukaryotic origin. In  particular, the term "sample" refers to a nucleic acid con› taining sample which also comprises cells. Preferably, the  sample is selected from the group consisting of cells, tissue,  body fluids such as for example blood, blood products such  as buffy coat, plasma and serum, urine, liquor, sputum, stool,  CSF and sperm, epithelial swabs, biopsies, bone marrow  samples and diverse tissue samples. The biological sample  may be preserved and e.g. may be contained in preservative  medium. E.g. the sample from which the nucleic acids are to  be isolated may have been stored in a preservative, including  but not limited to paraffin-embedded tissue samples and  cellular and tissue or cell samples stored in a liquid-based  cytology medium such as SUREPATHfi or PRESERV- CYTfi. Also other biomolecules such as e.g. proteins can be  isolated from the samples mentioned above which comprise  the respective biomolecule of interest. 