Ultrastructure (or ultra-structure) is the architecture of cells and biomaterials that is visible at higher magnifications than found on a standard optical light microscope. This traditionally meant the resolution and magnification range of a conventional

transmission electron microscope Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a gr ...

(TEM) when viewing biological specimens such as cells, tissue, or

organ Organ and organs may refer to: Biology * Organ (biology), a group of tissues organized to serve a common function * Organ system, a collection of organs that function together to carry out specific functions within the body. Musical instruments ...

s. Ultrastructure can also be viewed with

scanning electron microscopy A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that ...

and

super-resolution microscopy Super-resolution microscopy is a series of techniques in optical microscopy that allow such images to have Optical resolution, resolutions higher than those imposed by the Diffraction-limited system, diffraction limit, which is due to the diffra ...

, although TEM is a standard

histology Histology, also known as microscopic anatomy or microanatomy, is the branch of biology that studies the microscopic anatomy of biological tissue (biology), tissues. Histology is the microscopic counterpart to gross anatomy, which looks at large ...

technique for viewing ultrastructure. Such cellular structures as

organelle In cell biology, an organelle is a specialized subunit, usually within a cell (biology), cell, that has a specific function. The name ''organelle'' comes from the idea that these structures are parts of cells, as Organ (anatomy), organs are to th ...

s, which allow the cell to function properly within its specified environment, can be examined at the ultrastructural level. Ultrastructure, along with

molecular phylogeny Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

, is a reliable

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

way of classifying organisms. Features of ultrastructure are used industrially to control material properties and promote biocompatibility.

History

In 1931,

German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...

engineers Engineers, as practitioners of engineering, are professionals who invent, design, build, maintain and test machines, complex systems, structures, gadgets and materials. They aim to fulfill functional objectives and requirements while consider ...

Max Knoll Max Knoll (17 July 1897 – 6 November 1969) was a German electrical engineer and co-inventor of the electron microscope. Knoll was born in Wiesbaden and studied at the University of Munich and at the Technischen Hochschulen in Munich and ...

and

Ernst Ruska Ernst August Friedrich Ruska (; 25 December 1906 – 27 May 1988) was a German physicist who won the Nobel Prize in Physics in 1986 for his work in electron optics, including the design of the first electron microscope. Life and career Ernst R ...

invented the first electron microscope. With the development and invention of this microscope, the range of observable structures that were able to be explored and analyzed increased immensely, as biologists became progressively interested in the submicroscopic organization of cells. This new area of research concerned itself with substructure, also known as the ultrastructure.

Applications

Many scientists use ultrastructural observations to study the following, including but not limited to: * Human Tumors *

Chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

s *

Bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

Platelet Platelets or thrombocytes () are a part of blood whose function (along with the coagulation#Coagulation factors, coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a thrombus, blood clot. Platelets have no ...

s *

Sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

Biology

A common ultrastructural feature found in

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

cells is the formation of

calcium oxalate Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula or . It forms hydrates , where ''n'' varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydr ...

crystals. It has been theorized that these crystals function to store calcium within the cell until it is needed for growth or development. Calcium oxalate crystals can also form in

animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...

s, and

kidney stones Kidney stone disease (known as nephrolithiasis, renal calculus disease, or urolithiasis) is a crystallopathy and occurs when there are too many minerals in the urine and not enough liquid or hydration. This imbalance causes tiny pieces of cr ...

are a form of these ultrastructural features. Theoretically,

nanobacteria ''Nanobacterium'' ( , pl. ''nanobacteria'' ) is the unit or member name of a former proposed class of living organisms, specifically cell wall, cell-walled microorganisms, now discredited, with a size much smaller than the generally accepted l ...

could be used to decrease the formation of calcium oxalate kidney stones.

Engineering

Controlling ultrastructure has

engineering Engineering is the practice of using natural science, mathematics, and the engineering design process to Problem solving#Engineering, solve problems within technology, increase efficiency and productivity, and improve Systems engineering, s ...

uses for controlling the behavior of cells. Cells respond readily to changes in their

extracellular matrix In biology, the extracellular matrix (ECM), also called intercellular matrix (ICM), is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and bio ...

(ECM), so manufacturing materials to mimic ECM allows for increased control over the cell cycle and

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

expression. Many cells, such as plants, produce

crystals, and these crystals are usually considered ultrastructural components of plant cells. Calcium oxalate is a material that is used to manufacture

ceramic glaze Ceramic glaze, or simply glaze, is a glassy coating on ceramics. It is used for decoration, to ensure the item is impermeable to liquids and to minimize the adherence of pollutants. Glazing renders earthenware impermeable to water, sealing th ...

s and it also has

biomaterial A biomaterial is a substance that has been Biological engineering, engineered to interact with biological systems for a medical purpose – either a therapeutic (treat, augment, repair, or replace a tissue function of the body) or a Medical diag ...

properties. For culturing cells and

tissue engineering Tissue engineering is a biomedical engineering discipline that uses a combination of cells, engineering, materials methods, and suitable biochemical and physicochemical factors to restore, maintain, improve, or replace different types of biolo ...

, this crystal is found in fetal bovine serum, and is an important aspect of the extracellular matrix for culturing cells. Ultrastructure is an important factor to consider when engineering

dental implant A dental implant (also known as an endosseous implant or fixture) is a prosthesis that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown (dentistry), crown, bridge (dentistry), bridge, dentures, denture ...

s. Since these devices interface directly with bone, their incorporation to surrounding tissue is necessary to optimal device function. It has been found that applying a load to a healing dental implant allows for increased

osseointegration Osseointegration (from Latin " bony" and "to make whole") is the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant ("load-bearing" as defined by Albrektsson et al. in 1981). ...

with

facial bones The facial skeleton comprises the ''facial bones'' that may attach to build a portion of the skull. The remainder of the skull is the neurocranium. In human anatomy and development, the facial skeleton is sometimes called the ''membranous viscer ...

. Analyzing the ultrastructure surrounding an implant is useful in determining how biocompatible it is and how the body reacts to it. One study found implanting granules of a biomaterial derived from pig bone caused the human body to incorporate the material into its ultrastructure and form new bone.

Hydroxyapatite Hydroxyapatite (International Mineralogical Association, IMA name: hydroxylapatite) (Hap, HAp, or HA) is a naturally occurring mineral form of calcium apatite with the Chemical formula, formula , often written to denote that the Crystal struc ...

is a biomaterial used to interface medical devices directly to bone by ultrastructure.

Grafts Grafting refers to a surgical procedure to move tissue from one site to another on the body, or from another creature, without bringing its own blood supply with it. Instead, a new blood supply grows in after it is placed. A similar techniqu ...

can be created along with 𝛃-tricalcium phosphate, and it has been observed that surrounding bone tissue with incorporate the new material into its extracellular matrix. Hydroxyapatite is a highly biocompatible material, and its ultrastructural features, such as crystalline orientation, can be controlled carefully to ensure optimal biocompatibility. Proper crystal fiber orientation can make introduced minerals, like hydroxyapatite, more similar to the biological materials they intend to replace. Controlling ultrastructural features makes obtaining specific material properties possible.

References

External links

*{{Commonscat-inline Electron microscopy Cell anatomy