Function-Spacer-Lipid (FSL) Kode constructs (Kode Technology) are amphiphatic, water dispersible biosurface engineering constructs that can be used to engineer the surface of cells,

virus A virus is a wikt:submicroscopic, submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and ...

es and organisms, or to modify solutions and non-biological surfaces with bioactives. FSL Kode constructs spontaneously and stably incorporate into cell membranes. FSL Kode constructs with all these aforementioned features are also known as Kode Constructs. The process of modifying surfaces with FSL Kode constructs is known as "koding" and the resultant "koded" cells,

es and

liposome A liposome is a small artificial vesicle, spherical in shape, having at least one lipid bilayer. Due to their hydrophobicity and/or hydrophilicity, biocompatibility, particle size and many other properties, liposomes can be used as drug delive ...

s are respectively known as kodecytes, and kodevirions.

Technology description

All living surfaces are decorated with a diverse range of complex molecules, which are key modulators of

chemical communications ''ChemComm'' (or ''Chemical Communications''), formerly known as ''Journal of the Chemical Society D: Chemical Communications'' (1969–1971), ''Journal of the Chemical Society, Chemical Communications'' (1972–1995), is a peer-reviewed scientific ...

and other functions such as protection,

adhesion Adhesion is the tendency of dissimilar particles or surfaces to cling to one another ( cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another). The forces that cause adhesion and cohesion can b ...

infectivity In epidemiology, infectivity is the ability of a pathogen to establish an infection. More specifically, infectivity is a pathogen's capacity for horizontal transmission — that is, how frequently it spreads among hosts that are not in a parent ...

, apoptosis, etc. Functional-Spacer-Lipid (FSL) Kode constructs can be synthesized to mimic the bioactive components present on biological surfaces, and then re-present them in novel ways. The architecture of an FSL Kode construct, as implicit in the name, consists of three components - a functional head group, a spacer, and a lipid tail. This structure is analogous to a

Lego minifigure A Lego minifigure, commonly referred to as a minifig, is a small plastic articulated figurine produced by Danish toy manufacturer The Lego Group. They were first produced in 1978 and have been a success, with over 4 billion produced worldwid ...

in that, they have three structural components, with each component having a separate purpose. In the examples shown in all the figures, a Lego ' minifig' has been used for the analogy. However, it should be appreciated that this is merely a representation and the true structural similarity is significantly varied between Lego minifigures and FSL Kode constructs ''(fig 1)''. The functional group of an FSL is equivalent to a Lego minifigure head, with both being at the extremity and carrying the character functional components. The spacer of the FSL is equivalent to the body of the Lego minifigure and the arms on the minifigure are representative of substitutions which may be engineered into the chemical makeup of the spacer. The lipid of the FSL anchors it to lipid membranes and gives the FSL construct its amphiphatic nature which can cause it to self-assemble. Because the lipid tail can act directly as an anchor it is analogous to the legs of a Lego minifigure.

Flexible design

The functional group, the spacer and the lipid tail components of the FSL Kode construct can each be individually designed resulting in FSL Kode constructs with specific biological functions. The functional head group is usually the bioactive component of the construct and the various spacers and lipids influence and effect its presentation, orientation and location on a surface. Critical to the definition of an FSL Kode construct is the requirement to be dispersible in water, and spontaneously and stably incorporate into cell membranes. Other lipid bioconjugates that include components similar to FSLs but do not have these features are not termed as Function-Spacer-Lipid Kode constructs.

Functional groups

A large range of functional groups have already been made into FSL Kode constructs. These include: * Carbohydrates – ranging from

monosaccharide Monosaccharides (from Greek '' monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built. They are usually colorless, water-sol ...

s to

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with ...

s and including blood group

antigens In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. ...

hyaluronic acid Hyaluronic acid (; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminoglycan ...

oligomers In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers.Quote: ''Oligomer molecule: A molecule of intermediate relati ...

and

sialic acid Sialic acids are a class of alpha-keto acid sugars with a nine-carbon backbone. The term "sialic acid" (from the Greek for saliva, - ''síalon'') was first introduced by Swedish biochemist Gunnar Blix in 1952. The most common member of this ...

residues * Peptide/protein – ranging from single

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha ...

s to

proteins Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respondi ...

as large as antibodies * Labels – including

fluorophores A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescence, fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromaticity, aromatic groups, or planar o ...

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

s, biotin, etc. * Other – chemical moieties such as

maleimide Maleimide is a chemical compound with the formula H2C2(CO)2NH (see diagram). This unsaturated imide is an important building block in organic synthesis. The name is a contraction of maleic acid and imide, the -C(O)NHC(O)- functional group. Male ...

, click residues,

PEG PEG or peg may refer to: Devices * Clothes peg, a fastener used to hang up clothes for drying * Tent peg, a spike driven into the ground for holding a tent to the ground * Tuning peg, used to hold a string in the pegbox of a stringed instru ...

, charged compounds ''Note 1: Multimeric – the presentation of the F residue can be as

multimer In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers.Quote: ''Oligomer molecule: A molecule of intermediate relati ...

s with controlled spacing and be variable.'' ''Note 2: Mass – the mass that can be anchored by an FSL Kode constructs can range from 200 to >1x10⁶ Da''

Spacers

The spacer is an integral part of the FSL Kode construct and gives it several important characteristics including water dispersibility. * Length – the spacer can be varied in length, for example 1.9 nm (Ad), 7.2 nm (CMG2), 11.5 nm (CMG4), allowing for enhanced presentation of Functional groups at the biosurface. * Optimizes 'F' presentation – The presentation of the bioactive (functional group) on a spacer reduces

steric hindrance Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivity of ions ...

and increases the bioactive surfaces exposed and available for interactions * Rigidity – the spacer can be modified to be either flexible or rigid depending upon desired characteristics * Substitutions (represented by the leaves on the stalk) – the spacer can be modified both in charge, and

polarity Polarity may refer to: Science * Electrical polarity, direction of electrical current * Polarity (mutual inductance), the relationship between components such as transformer windings * Polarity (projective geometry), in mathematics, a duality of o ...

. * Branches – usually the spacer is linear, but it can also be branched including specific spacing of the branches to optimize presentation and interaction of the F group. * Inert – important to the design of FSL Kode constructs is the biologically inert nature of the spacer. Importantly this feature means the S-L components of the constructs are unreactive with undiluted serum. Consequently, the constructs are compatible ''

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...

'' use, and can improve diagnostic assay sensitivity by allowing for the use of undiluted serum.

Lipids

The

lipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids incl ...

tail is essential for enabling

lipid membrane The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells. The cell membranes of almost all organisms and many ...

insertion and retention but also for giving the construct

amphiphilic An amphiphile (from the Greek αμφις amphis, both, and φιλíα philia, love, friendship), or amphipath, is a chemical compound possessing both hydrophilic (''water-loving'', polar) and lipophilic (''fat-loving'') properties. Such a compoun ...

characteristics that enable

hydrophilic A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are ...

surface coating (due to formation of bilipid layers). Different

membrane lipids Membrane lipids are a group of compounds (structurally similar to fats and oils) which form the double-layered surface of all cells (lipid bilayer). The three major classes of membrane lipids are phospholipids, glycolipids, and cholesterol. Lipid ...

that can be used to create FSLs have different membrane physiochemical characteristics and thus can affect biological function of the FSL. Lipids in FSL Kode constructs include: * Diacyl/diakyl e.g. DOPE * Sterols e.g. cholesterol * Ceramides

Optimising functional group (F) presentation

One of the important functions of an FSL construct is that it can optimise the presentation of

antigen In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. ...

s, both on cell surfaces and solid-phase membranes. This optimisation is achieved primarily by the spacer, and secondarily by the lipid tail. In a typical

immunoassay An immunoassay (IA) is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody (usually) or an antigen (sometimes). The molecule detected by the immunoass ...

, the antigen is deposited directly onto the

microplate A microplate, also known as a microtiter plate (''Microtiter'' is a registered trademark in the United States, therefore it should not be used generically without attribution), microwell plate or multiwell, is a flat plate with multiple "wells" ...

surface and binds to the surface either in a random fashion, or in a preferred orientation depending on the residues present on the surface of this antigen. Usually this deposition process is uncontrolled. In contrast, the FSL Kode construct bound to a microplate presents the antigen away from the surface in an orientation with a high level of exposure to the environment. Furthermore, typical immunoassays use recombinant

peptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. ...

s rather than discrete peptide antigens. As the recombinant peptide is many times bigger than the

epitope An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The epitope is the specific piece of the antigen to which an antibody binds. The ...

of interest, a lot of undesired and unwanted peptide sequences are also represented on the microplate. These additional sequences may include unwanted microbial related sequences (as determined by a

BLAST Blast or The Blast may refer to: *Explosion, a rapid increase in volume and release of energy in an extreme manner *Detonation, an exothermic front accelerating through a medium that eventually drives a shock front Film * ''Blast'' (1997 film), ...

analysis) that can cause issues of low level cross-reactivity. Often the mechanism by which an immunoassay is able to overcome this low level activity is to dilute the serum so that the low level microbial reactive antibodies are not seen, and only high-level specific antibodies result in an interpretable result. In contrast, FSL Kode constructs usually use specifically selected peptide fragments (up to 40 amino acids), thereby overcoming cross-reactivity with microbial sequences, and allowing for the use of undiluted

serum Serum may refer to: *Serum (blood), plasma from which the clotting proteins have been removed **Antiserum, blood serum with specific antibodies for passive immunity * Serous fluid, any clear bodily fluid * Truth serum, a drug that is likely to mak ...

(which increases

sensitivity Sensitivity may refer to: Science and technology Natural sciences * Sensitivity (physiology), the ability of an organism or organ to respond to external stimuli ** Sensory processing sensitivity in humans * Sensitivity and specificity, statisti ...

). The F component can be further enhanced by presentation of it in multimeric formats and with specific spacing. The four types of multimeric format include linear repeating units, linear repeating units with spacing, clusters, and branching ''(Fig. 4)''.

Mechanisms of interaction

Amphiphilic FSL Kode construct

The FSL Kode construct by nature of its composition in possessing both hydrophobic and hydrophilic regions are

(or amphipathic). This characteristic determines the way in which the construct will interact with surfaces. When present in a solution they may form simple

micelles A micelle () or micella () (plural micelles or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloidal suspension (also known as associated colloi ...

or adopt more complex bilayer structures with two simplistic examples shown in ''Fig. 5a''. More complex structures are expected. The actual nature of FSL micelles has not been determined. However, based on normal structural function of micelles, it is expected that it will be determined in part by the combination of functional group, spacer and lipid together with temperature,

concentration In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', '' molar concentration'', '' number concentration'' ...

, size and hydrophobicity/hydrophilicity for each FSL Kode construct type. Surface coatings will occur via two theoretical mechanisms, the first being direct hydrophobic interaction of the lipid tail with a hydrophobic surface resulting in a

monolayer A monolayer is a single, closely packed layer of atoms, molecules, or cells. In some cases it is referred to as a self-assembled monolayer. Monolayers of layered crystals like graphene and molybdenum disulfide are generally called 2D materials. ...

of FSL at the surface ''(Fig. 5b)''. Hydrophobic binding of the FSL will be via its hydrophobic lipid tail interacting directly with the hydrophobic (

lipophilic Lipophilicity (from Greek λίπος "fat" and φίλος "friendly"), refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such non-polar solvents are themselves li ...

) surface. The second surface coating will be through the formation of bilayers as the lipid tail is unable to react with the hydrophilic surface. In this case the lipids will induce the formation of a bilayer, the surface of which will be hydrophilic. This hydrophilic membrane will then interact directly with the hydrophilic surface and will probably encapsulate

fibres Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...

. This hydrophilic bilayer binding is the expected mechanism by which FSLs are able to bind to fibrous membranes such as paper and glass fibres ''(Fig. 5c)'' and ''(Fig. 9)''.

Lipid membrane modification

After labeling of the surface with the selected F bioactives, the constructs will be present and oriented at the membrane surface. It is expected that the FSL will be highly mobile within the membrane and the choice of lipid tail will effect is relative partitioning within the membrane. The construct unless it has flip-flop behavior is expected to remain surface presented. However, the modification is not permanent in living cells and constructs will be lost (consumed) at a rate proportional to the activity at the membrane and division rate of the cell (with dead cells remaining highly labeled). Additionally, when present ''in vivo'' with serum lipids FSLs will elute from the membrane into the plasma at a rate of about 1% per hour. In fixed cells or inactive cells (e.g. red cells) stored in serum free media the constructs are retained normally. Liposomes are easy koded by simply adding FSL Kode constructs into the preparation. Contacting koded liposomes with microplates or other surfaces can cause the labeling of the microplate surface.

Non-biologic surface interaction

Non-biologic surface coatings will occur via two mechanisms, the first being direct hydrophobic interaction of the lipid tail with a hydrophobic surface resulting in a monolayer of FSL at the surface. The second surface coating will be through the formation of bilayers, which probably either encapsulate fibres or being via the hydrophilic F group. This is the expected mechanism by which FSLs bind to fibrous membranes such as paper and glass fibres. A recent study has found that when FSL Kode constructs are optimised, could in a few seconds glycosylate almost any non-biological surface including metals, glass, plastics, rubbers, and other polymers.

Technology features

The technological features of FSL Kode constructs and the koding process can be summarized as follows: * Rapid and simple – simple contact for 10–120 minutes and constructs spontaneously and stably incorporate – no washing required. * Replicable – same variables (time, temperature, concentration) equals the same result. * Toxicity – FSL constructs are

biocompatible Biocompatibility is related to the behavior of biomaterials in various contexts. The term refers to the ability of a material to perform with an appropriate host response in a specific situation. The ambiguity of the term reflects the ongoing de ...

, disperse into biological solutions without

solvents A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

, detergents. They label non-covalently and are non-genetic. Normal

vitality Vitality (, , ) is the capacity to live, grow, or develop. More simply it is the property of having life. The perception of vitality is regarded as a basic psychological drive and, in philosophy, a component to the will to live. As such, peo ...

and functionality is maintained in modified cells/virions/organisms. Toxicity/vitality experiments in small laboratory animals,

zebrafish The zebrafish (''Danio rerio'') is a freshwater fish belonging to the minnow family (Cyprinidae) of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (and thus often c ...

, cell cultures,

spermatozoa A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell (biology), cell, or moving form of the ploidy, haploid cell (biology), cell that is the male gamete. A spermatozoon Fertilization, joins an ovum to form a zygote. (A zygote ...

and

embryos An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm c ...

find no

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

effects within physiological ranges. * Amphiphilic – the

nature of the FSL Kode construct makes them water dispersible (clear solution of micelles), yet once interacted with a membrane they insert/coat and become water resistant * Variable design – a single F can be presented in more than 100 ways by varying the spacer and lipid. * High biovisibility – as the spacer holds the F moiety away for the membrane it is able to achieve increased sensitivity, specificity and reactivity can be optimized by use of multiple and variable biomarker presentations on the same surface. * Additive – FSL modification is compatible with other technologies allowing users to add additional features to cells/viruses/organisms/surfaces already modified by more traditional methods. Multiple FSL constructs may be added to a surface simultaneously by simply creating a mix of FSL Kode constructs. Constructs insert into living or fixed cell (

glutaraldehyde Glutaraldehyde is an organic compound with the formula . The molecule consists of a five carbon chain doubly terminated with formyl (CHO) groups. It is usually used as a solution in water, and such solutions exists as a collection of hydrates, c ...

) membranes. RFG maleimide construction

* Simple FSL peptide synthesis – there is a reactive-functional-group FSL Kode construct with maleimide as its functional group which can be used for preparation of FSLs from

cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, s ...

-containing peptides, proteins or any other

thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

s of biological interest. The effective synthetic approach is based on the well-known Michael nucleophilic addition to maleimides ''(Fig. 7)''. * Synthetic "Gylcolipids" – one family of the FSL constructs are synthetic

glycolipid Glycolipids are lipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the conne ...

s with well-defined hydrophobic tails and carbohydrate head groups

Koded membranes surfaces and solutions

FSL constructs have a wide range of uses and they have been used to modify the following: * Cells –

blood cell A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), ...

s, culture lines,

* Viruses – influenza, measles, varicella * Organisms –

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...

microbe A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

* Liposomes – also micelles, lipid particles * Surfaces/fibres – hydrophobic or hydrophilic membranes/fibres, paper,

nitrocellulose Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...

, cotton, silk, glass,

Teflon Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chem ...

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is o ...

, magnetic beads (microspheres) etc. * Solutions – saline, plasma/serum, culture media

Methodology for FSL use (koding)

Preparation of kodecytes and kodevirions

FSL constructs, when in solution ( saline) and in contact, will spontaneously incorporate into cell and virus membranes. The methodology involves simply preparing a solution of FSL constructs in the range of 1–1000

μg In the metric system, a microgram or microgramme is a unit of mass equal to one millionth () of a gram. The unit symbol is μg according to the International System of Units (SI); the recommended symbol in the United States and United Kingdom whe ...

/ mL. The actual concentration will depend on the construct and the quantity of construct required in the membrane. One part of FSL solution is added to one part of cells (up to 100%

suspension Suspension or suspended may refer to: Science and engineering * Suspension (topology), in mathematics * Suspension (dynamical systems), in mathematics * Suspension of a ring, in mathematics * Suspension (chemistry), small solid particles suspen ...

) and they are incubated at a set temperature within the range of 4–37 °C (39–99 °F) depending on temperature compatibility of the cells being modified. The higher the temperature, the faster the rate of FSL insertion into the membrane. For red blood cells, at 37 °C incubation for 2 hours achieves >95% insertion with at least 50% insertion being achieved within 20 minutes. In general, FSL insertion time of 4 hours at room temperature or 20 hours at 4 °C gives results similar to 1 hour at 37 °C for carbohydrate based FSLs inserting into red blood cells. The resultant kodecytes or kodevirions do not required to be washed, however this option should be considered if an excess of FSL construct is used in the koding process.

Applications

FSL Kode constructs have been used for research and development,

diagnostic Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engine ...

products, and are currently being investigated as potential

therapeutic A therapy or medical treatment (often abbreviated tx, Tx, or Tx) is the attempted remediation of a health problem, usually following a medical diagnosis. As a rule, each therapy has indications and contraindications. There are many differe ...

agents.

Kodecytes

FSL have been used to create human red cell kodecytes that have been used to detect and identify blood group allo-antibodies as ABO sub-group mimics, ABO quality control systems,

serologic Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection (against a given mi ...

teaching kits and a syphilis diagnostic. Kodecytes have also demonstrated that FSL-FLRO4 is a suitable reagent for labelling

packed red blood cells Packed red blood cells, also known as packed cells, are red blood cells that have been separated for blood transfusion. The packed cells are typically used in anemia that is either causing symptoms or when the hemoglobin is less than usually 70� ...

(PRBC) at any point during routine storage and look to facilitate the development of immunoassays and transfusion models focused on addressing the mechanisms involved in tansfusion-related immunomodulation (TRIM). Murine kodecytes have been experimentally used to determine ''in vivo'' cell survival, and create model

transfusion reactions Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but mod ...

. Zebrafish kodecytes have been used to determine real time ''in vivo'' cell migration. Kodecytes have been used to create influenza diagnostics. Kodecytes which have been modified with FSL-GB3 were unable to be infected with the

HIV virus The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immun ...

Kodevirions

Kodevirions are FSL modified viruses. Several FSL Kode constructs have been used to label viruses to assist in their flow-cytometric visualisation and to track them real time distribution in animal models. They have also been used to modify the surface of viruses with the intention of targeting them to be used to attach

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

s ( oncolytic).

Kodesomes

Kodesomes are liposomes that have been decorated with FSL Kode constructs. These have been used to deposit FSL constructs onto microplates to create diagnostic

assay An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of ...

s. They also have the potential for therapeutic use.

Koded solutions

These are solutions containing FSL Kode constructs where the construct will exist as a clear micellular dispersion. FSL-GB3 as a solution/gel has been used to inhibit HIV infection and to neutralise

Shiga toxin Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, expressed by genes considered to be part of the genome of lambdoid prophages. The toxins are named after Kiyoshi Shiga, who first described the bacterial ori ...

. FSL blood group A as a solution has been used to neutralise circulating antibodies in a

mouse A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

model and allow incompatible blood group A (

murine The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. Members of this subfamily are called murines. In terms of species richness, this subfamily is larger than all mammal families ex ...

kodecytes) transfusion. This model experiment was used to demonstrate the potential of FSLs to neutralise circulating antibody and allow for incompatible blood transfusion or

organ transplantation Organ transplantation is a medical procedure in which an organ (anatomy), organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organ ...

Koded surfaces

All FSL Kode constructs disperse in water and are therefore compatible with

inkjet printer Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensi ...

s. FSL constructs can be printed with a standard desktop inkjet printer directly onto paper to create immunoassays. An empty ink cartridge is filled with an FSL construct and words,

barcode A barcode or bar code is a method of representing data in a visual, Machine-readable data, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly refe ...

s, or graphics are printed. A

Perspex Poly(methyl methacrylate) (PMMA) belongs to a group of materials called engineering plastics. It is a transparent thermoplastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and brands Crylux, Plexiglas, Acrylite ...

template is adhered to the surface to create reaction wells. The method is then a standard

EIA Eia or EIA may refer to: Medicine * Enzyme immunoassay * Equine infectious anemia * Exercise-induced anaphylaxis * Exercise-induced asthma * External iliac artery Transport * Edmonton International Airport, in Alberta, Canada * Erbil Internati ...

procedure, but blocking of serum is not required and undiluted serum can be used. A typical procedure is as follows: add serum, incubate, wash by immersion, add secondary EIA conjugate, incubate, wash, add NBT/

BCIP 5-Bromo-4-chloro-3-indolyl phosphate (BCIP, X-phosphate, XP) is an artificial chromogenic substrate used for the sensitive colorimetric detection of alkaline phosphatase activity. It is, for example, used in immunoblotting, in situ hybridization ...

precipitating substrate and stop the reaction when developed by washing ''(Fig. 9)''. The end result is stable for years.

External links

FSL Constructs: A Simple Method for Modifying Cell/Virion Surfaces with a Range of Biological Markers Without Affecting their Viability
– Journal of Visualised Experiments (JOVE) free video article

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