multifunctional nanoparticles (in medicine)
(rus. наночастицы, многофункциональные (в медицине) otherwise наносомы; динамические наноплатформы)
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nanoparticles and their complexes used in medicine that have multiple functions, i.e. act as a contrast agent in diagnostics, a biosensor, a vector for targeted drug delivery of drugs, or have a therapeutic effect.
Description
Multifunctional, or so-called dynamic nanoplatforms (nanosomes) and tecto-dendrimers comprised of interconnected nanomodules, each having been developed to fulfil a specific function. Some nanoparticles comprising a nanosome may carry drugs, others are molecules for targeted delivery, others may fulfil the role of biosensors (pH, redox potential, membrane potential, etc), and still others may carry nanoantennae made of gold nanocrystals that heat the nanosome when placed in an electromagnetic field with a certain frequency. Superparamagnetic nanoparticles attached to a nanosome enable nanosome visualisation using tomography. Fluorescence-based nanomodules that monitor the efficacy of nanomedical therapy, e.g. tumour cell death have been developed. Depending on a specific medical objective, nanosomes can be comprised of different functional modules and carry out several tasks, e.g. internal environment monitoring, visualisation of target cells, drug delivery and controlled drug release, treatment monitoring . Non-modular multifunctional nanoparticles include, for example, modified viral capsids. When these particles are assembling, both the content of the capsid (payload) and the composition of the capsid surface molecules responsible for targeted delivery and certain sensory functions may be changed. Nanosomes and other above-mentioned multifunctional nanodevices may be considered as prototypes of medical nanorobots.
A schematic polymer model of a multifunctional medical nanoparticle is shown on a figure. The solubilizing block (which can be represented by a polymer chain) allows the nanoparticle to operate in a biological medium (blood, lymph, etc.). The particle’s hydrophilicity/hydrophobicity, electrostatic charge and its density effect the pharmacokinetic and pharmacodynamic properties of a drug. Polymer chains may differ in terms of stability, size, composition and the presence of specific domains (e.g., hydrophobic segments). Polymer molecular weight affects the membrane-penetrating ability of the drug (passing through the blood-brain barrier and endocytosis stimulation). An active pharmaceutical agent (pharmacon) may be bound to the polymer base (or enclosed in nanocontainer) via a biodegradable or stable bond, being an inactive drug precursor, or an active metabolite (active pharmaceutical ingredient). A “targeting device” acts as a vector (may be represented by antibodies, molecules appearing in the affected area, protein domains with specific sorption/binding properties, etc.) that guides a nanoparticle to a given segment of a tissue or target organ. In a biosystem a conjugate obtains the conformation that facilitates the assembly of a conjugate-based multifunctional therapeutic nanoparticle.
A schematic polymer model of a multifunctional medical nanoparticle is shown on a figure. The solubilizing block (which can be represented by a polymer chain) allows the nanoparticle to operate in a biological medium (blood, lymph, etc.). The particle’s hydrophilicity/hydrophobicity, electrostatic charge and its density effect the pharmacokinetic and pharmacodynamic properties of a drug. Polymer chains may differ in terms of stability, size, composition and the presence of specific domains (e.g., hydrophobic segments). Polymer molecular weight affects the membrane-penetrating ability of the drug (passing through the blood-brain barrier and endocytosis stimulation). An active pharmaceutical agent (pharmacon) may be bound to the polymer base (or enclosed in nanocontainer) via a biodegradable or stable bond, being an inactive drug precursor, or an active metabolite (active pharmaceutical ingredient). A “targeting device” acts as a vector (may be represented by antibodies, molecules appearing in the affected area, protein domains with specific sorption/binding properties, etc.) that guides a nanoparticle to a given segment of a tissue or target organ. In a biosystem a conjugate obtains the conformation that facilitates the assembly of a conjugate-based multifunctional therapeutic nanoparticle.
Illustrations
Author
- Shirinsky Vladimir P.
Sources
- Freitas, R. A. Current status of nanomedicine and medical nanorobotics // J. Comp. Theo. Nanosci. 2005. V. 2. P. 1–25.
- Mendeleev Chemistry Journal (Zhurnal Vses. Khim. Ob-va im. Mendeleeva) (in Russian). The volume is dedicated to targeted transport of drugs. 1987. V. 34, No5.