A micelle or micella is an aggregate of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloidal suspension. A typical micelle in water forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre.
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 delivery vehicles for administration of pharmaceutical drugs and nutrients, such as lipid nanoparticles in mRNA vaccines, and DNA vaccines. Liposomes can be prepared by disrupting biological membranes.
In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are sometimes called bipolymers. Those obtained from three and four monomers are called terpolymers and quaterpolymers, respectively. Copolymers can be characterized by a variety of techniques such as NMR spectroscopy and size-exclusion chromatography to determine the molecular size, weight, properties, and composition of the material.
Targeted drug delivery, sometimes called smart drug delivery, is a method of delivering medication to a patient in a manner that increases the concentration of the medication in some parts of the body relative to others. This means of delivery is largely founded on nanomedicine, which plans to employ nanoparticle-mediated drug delivery in order to combat the downfalls of conventional drug delivery. These nanoparticles would be loaded with drugs and targeted to specific parts of the body where there is solely diseased tissue, thereby avoiding interaction with healthy tissue. The goal of a targeted drug delivery system is to prolong, localize, target and have a protected drug interaction with the diseased tissue. The conventional drug delivery system is the absorption of the drug across a biological membrane, whereas the targeted release system releases the drug in a dosage form. The advantages to the targeted release system is the reduction in the frequency of the dosages taken by the patient, having a more uniform effect of the drug, reduction of drug side-effects, and reduced fluctuation in circulating drug levels. The disadvantage of the system is high cost, which makes productivity more difficult, and the reduced ability to adjust the dosages.
Poloxamers are nonionic triblock copolymers composed of a central hydrophobic chain of polyoxypropylene flanked by two hydrophilic chains of polyoxyethylene. The word poloxamer was coined by BASF inventor, Irving Schmolka, who received the patent for these materials in 1973. Poloxamers are also known by the trade names Pluronic, Kolliphor, and Synperonic.
Small-angle X-ray scattering (SAXS) is a small-angle scattering technique by which nanoscale density differences in a sample can be quantified. This means that it can determine nanoparticle size distributions, resolve the size and shape of (monodisperse) macromolecules, determine pore sizes, characteristic distances of partially ordered materials, and much more. This is achieved by analyzing the elastic scattering behaviour of X-rays when travelling through the material, recording their scattering at small angles. It belongs to the family of small-angle scattering (SAS) techniques along with small-angle neutron scattering, and is typically done using hard X-rays with a wavelength of 0.07 – 0.2 nm. Depending on the angular range in which a clear scattering signal can be recorded, SAXS is capable of delivering structural information of dimensions between 1 and 100 nm, and of repeat distances in partially ordered systems of up to 150 nm. USAXS can resolve even larger dimensions, as the smaller the recorded angle, the larger the object dimensions that are probed.
Janus particles are special types of nanoparticles or microparticles whose surfaces have two or more distinct physical properties. This unique surface of Janus particles allows two different types of chemistry to occur on the same particle. The simplest case of a Janus particle is achieved by dividing the particle into two distinct parts, each of them either made of a different material, or bearing different functional groups. For example, a Janus particle may have one half of its surface composed of hydrophilic groups and the other half hydrophobic groups, the particles might have two surfaces of different color, fluorescence, or magnetic properties. This gives these particles unique properties related to their asymmetric structure and/or functionalization.
A nanocarrier is nanomaterial being used as a transport module for another substance, such as a drug. Commonly used nanocarriers include micelles, polymers, carbon-based materials, liposomes and other substances. Nanocarriers are currently being studied for their use in drug delivery and their unique characteristics demonstrate potential use in chemotherapy. This class of materials was first reported by a team of researchers of University of Évora, Alentejo in early 1960's, and grew exponentially in relevance since then.
Nanoparticles for drug delivery to the brain is a method for transporting drug molecules across the blood–brain barrier (BBB) using nanoparticles. These drugs cross the BBB and deliver pharmaceuticals to the brain for therapeutic treatment of neurological disorders. These disorders include Parkinson's disease, Alzheimer's disease, schizophrenia, depression, and brain tumors. Part of the difficulty in finding cures for these central nervous system (CNS) disorders is that there is yet no truly efficient delivery method for drugs to cross the BBB. Antibiotics, antineoplastic agents, and a variety of CNS-active drugs, especially neuropeptides, are a few examples of molecules that cannot pass the BBB alone. With the aid of nanoparticle delivery systems, however, studies have shown that some drugs can now cross the BBB, and even exhibit lower toxicity and decrease adverse effects throughout the body. Toxicity is an important concept for pharmacology because high toxicity levels in the body could be detrimental to the patient by affecting other organs and disrupting their function. Further, the BBB is not the only physiological barrier for drug delivery to the brain. Other biological factors influence how drugs are transported throughout the body and how they target specific locations for action. Some of these pathophysiological factors include blood flow alterations, edema and increased intracranial pressure, metabolic perturbations, and altered gene expression and protein synthesis. Though there exist many obstacles that make developing a robust delivery system difficult, nanoparticles provide a promising mechanism for drug transport to the CNS.
Magnetic nanoparticle-based drug delivery is a means in which magnetic particles such as iron oxide nanoparticles are a component of a delivery vehicle for magnetic drug delivery, due to the simplicity with which the particles can be drawn to (external) magnetopuissant targets. Magnetic nanoparticles can impart imaging and controlled release capabilities to drug delivery materials such as micelles, liposomes, and polymers.
Christine Allen is a Canadian professor and the first associate vice-president and vice-provost for strategic initiatives at the University of Toronto. She served formerly as interim dean of the university's Leslie Dan Faculty of Pharmacy. She is co-founder of Nanovista, a company focused on imaging of tumors. She also works as the associate editor of Molecular Pharmaceutics.
Nanoparticle drug delivery systems are engineered technologies that use nanoparticles for the targeted delivery and controlled release of therapeutic agents. The modern form of a drug delivery system should minimize side-effects and reduce both dosage and dosage frequency. Recently, nanoparticles have aroused attention due to their potential application for effective drug delivery.
So-Jung Park 박소정(朴昭靜) is a professor of chemistry at Ewha Womans University, Republic of Korea. Her research considers the self-assembly of nanoparticles and functional molecules for biomedical and optoelectronic devices. She serves as Associate Editor of ACS Applied Materials & Interfaces and Nanoscale.
Polymer-protein hybrids are a class of nanostructure composed of protein-polymer conjugates. The protein component generally gives the advantages of biocompatibility and biodegradability, as many proteins are produced naturally by the body and are therefore well tolerated and metabolized. Although proteins are used as targeted therapy drugs, the main limitations—the lack of stability and insufficient circulation times still remain. Therefore, protein-polymer conjugates have been investigated to further enhance pharmacologic behavior and stability. By adjusting the chemical structure of the protein-polymer conjugates, polymer-protein particles with unique structures and functions, such as stimulus responsiveness, enrichment in specific tissue types, and enzyme activity, can be synthesized. Polymer-protein particles have been the focus of much research recently because they possess potential uses including bioseparations, imaging, biosensing, gene and drug delivery.
Dextran drug delivery systems involve the use of the natural glucose polymer dextran in applications as a prodrug, nanoparticle, microsphere, micelle, and hydrogel drug carrier in the field of targeted and controlled drug delivery. According to several in vitro and animal research studies, dextran carriers reduce off-site toxicity and improve local drug concentration at the target tissue site. This technology has significant implications as a potential strategy for delivering therapeutics to treat cancer, cardiovascular diseases, pulmonary diseases, bone diseases, liver diseases, colonic diseases, infections, and HIV.
Pullulan bioconjugates are systems that use pullulan as a scaffold to attach biological materials to, such as drugs. These systems can be used to enhance the delivery of drugs to specific environments or the mechanism of delivery. These systems can be used in order to deliver drugs in response to stimuli, create a more controlled and sustained release, and provide a more targeted delivery of certain drugs.
Chitosan-poly is a composite that has been increasingly used to create chitosan-poly(acrylic acid) nanoparticles. More recently, various composite forms have come out with poly(acrylic acid) being synthesized with chitosan which is often used in a variety of drug delivery processes. Chitosan which already features strong biodegradability and biocompatibility nature can be merged with polyacrylic acid to create hybrid nanoparticles that allow for greater adhesion qualities as well as promote the biocompatibility and homeostasis nature of chitosan poly(acrylic acid) complex. The synthesis of this material is essential in various applications and can allow for the creation of nanoparticles to facilitate a variety of dispersal and release behaviors and its ability to encapsulate a multitude of various drugs and particles.
Polystyrene is a synthetic hydrocarbon polymer that is widely adaptive and can be used for a variety of purposes in drug delivery. These methods include polystyrene microspheres, nanoparticles, and solid foams. In the biomedical engineering field, these methods assist researchers in drug delivery, diagnostics, and imaging strategies.
Reduction-sensitive nanoparticles (RSNP) consist of nanocarriers that are chemically responsive to reduction. Drug delivery systems using RSNP can be loaded with different drugs that are designed to be released within a concentrated reducing environment, such as the tumor-targeted microenvironment. Reduction-Sensitive Nanoparticles provide an efficient method of targeted drug delivery for the improved controlled release of medication within localized areas of the body.
pH-responsive tumor-targeted drug delivery is a specialized form of targeted drug delivery that utilizes nanoparticles to deliver therapeutic drugs directly to cancerous tumor tissue while minimizing its interaction with healthy tissue. Scientists have used drug delivery as a way to modify the pharmacokinetics and targeted action of a drug by combining it with various excipients, drug carriers, and medical devices. These drug delivery systems have been created to react to the pH environment of diseased or cancerous tissues, triggering structural and chemical changes within the drug delivery system. This form of targeted drug delivery is to localize drug delivery, prolongs the drug's effect, and protect the drug from being broken down or eliminated by the body before it reaches the tumor.
