Amphiphilic Complex Research Articles

Amphiphilic Polyelectrolyte Complexes for Fouling-Resistant and Easily Tunable Membranes.

Commercial membranes today are manufactured from a handful of membrane materials. While these systems are well-optimized, their capabilities remain constrained by limited chemistries and manufacturing methods available. As a result, membranes cannot address many relevant separations where precise selectivity is needed, especially with complex feeds. This constraint requires the development of novel membrane materials that offer customizable features to provide specific selectivity and durability requirements for each application, enabled by incorporating different functional chemistries into confined nanopores in a scalable process. This study introduces a new class of membrane materials, amphiphilic polyelectrolyte complexes (APECs), comprised of a blend two distinct amphiphilic polyelectrolytes of opposite charge that self-assemble to form a polymer selective layer. When coated on a porous support from a mixture in a nonaqueous solvent, APECs self-assemble to create ionic nanodomains acting as water-conducting nanochannels, enveloped within hydrophobic nanodomains, ensuring structural integrity of the layer in water. Notably, this approach allows precise control over selectivity without compromising pore size, permeability, or fouling resistance. For example, using only one pair of amphiphilic copolymers, sodium sulfate rejections can be varied from >95% to <10% with no change in effective pore size and fouling resistance. Given the wide range of amphiphilic polyelectrolytes (i.e., combinations of different hydrophobic, anionic, and cationic monomers), APECs can create membranes with many diverse chemistries and selectivities. Resultant membranes can potentially address precision separations in many applications, from wastewater treatment to chemical and biological manufacturing.

Solubility enhancement of β-ionone with lipidic, amphiphilic, and inclusion complex: extensive polymeric biomaterials to develop formulations for poorly soluble drugs

Solubility enhancement of β-ionone with lipidic, amphiphilic, and inclusion complex: extensive polymeric biomaterials to develop formulations for poorly soluble drugs

Engineering the Spatial Distribution of Amphiphilic Molecule within Complex Coacervate Microdroplet via Modulating Charge Strength of Polyelectrolytes.

The investigation of the interplay between complex coacervate microdroplets and amphiphilic molecules offers valuable insights into the processes of prebiotic compartmentalization on the early Earth and presents a promising avenue for future advancements in biotechnology. Herein, the interaction between complex coacervate microdroplets and amphiphilic molecule (decanoic acid) is systematically investigated by varying charge strengths of negatively charged polyelectrolytes (DNA and PAA) and positively charged polyelectrolytes (PDDA and DEAE-Dextran). It is found that the interaction between amphiphilic molecule and complex coacervate microdroplets depended on the delicate balance between the interaction between decanoic acid and polyelectrolyte and the interaction between two polyelectrolytes. The different spatial distribution of amphiphilic molecule can result in differences in the internal microenvironment, which can further alter the uptake or exclusion of small molecules and biomolecules with different charges and polarities and functional biological process.

Pickering extremulsion rich in lipophilic phytochemicals: Preparation, characterization and application

The stability and use convenience of lipophilic phytochemicals are needed in the food or medicine fields. In this work, a new and environmentally friendly process for efficient extraction and formulation of lipophilic phytochemicals from plant had been successfully developed. A medium system consisting of water, tributyrin oil and natural amphiphilic complex particles (SPICS) was established. Under the optimal conditions of the oil/water ratio 10%, the particle concentration 2%, solid-liquid ratio 35:1 (mg/mL), ultrasound time 90 s and ultrasound power 300 W, the stable and uniform Pickering extremulsion rich in phytochemical lipophilic cannabidiol（CBD）from industrial hemp leaves was prepared. The Pickering extremulsion with the highest CBD content 1.06 mg/g was obtained, which increased 1.17-fold to the traditional Soxhlet extraction. Meanwhile, the CBD-rich Pickering extremulsion had an excellent antibacterial, antioxidant activity and cell activity with bacteriostatic diameter 7.5–18 mm, DPPH clearance rate 61.8% and cell activity of more than 80%. Besides, CBD-rich Pickering extremulsion had good bioaccessibility. In conclusion, the study provided a green, efficient and low-cost approach for simultaneous extraction and preparation of lipophilic phytochemicals, and it should provide some valuable insights for its application as nutrient or active carriers in phytochemicals field.

Oxygen and pH responsive theragnostic liposomes for early-stage diagnosis and photothermal therapy of solid tumours.

The development of cancer treatment is of great importance, especially in the early stage. In this work, we synthesized a pH-sensitive amphiphilic ruthenium complex containing two alkyl chains and two PEG chains, which was utilized as an oxygen sensitive fluorescent probe for co-assembly with lipids to harvest a liposomal delivery system (RuPC) for the encapsulation of a photothermal agent indocyanine green (ICG). The resultant ICG encapsulated liposome (RuPC@ICG) enabled the delivery of ICG into cells via a membrane fusion pathway, by which the ruthenium complex was localized in the cell membrane for better detection of the extracellular oxygen concentration. Such characteristics allowed ratiometric imaging to distinguish the tumour location from normal tissues just 3 days after cancer cells were implanted, by monitoring the hypoxia condition and tracing the metabolism. Moreover, the pH sensitivity of the liposomes favoured cell uptake, and improved the anti-tumour efficiency of the formulation in vivo under NIR irradiation. Assuming liposomal systems have fewer safety issues, our work not only provides a facile method for the construction of a theragnostic system by combining phototherapy with photoluminescence imaging, but hopefully paves the way for clinical translation from bench to bedside.

Bifunctional drug delivery system with carbonic anhydrase IX targeting and glutathione-responsivity driven by host-guest amphiphiles for effective tumor therapy

It remains a critical issue to deliver anticancer drugs to tumor tissues and reducing the toxic effects on normal tissues. The drug delivery system (DDS) based on self-assembly provides a multi-functional way for drug delivery. In this work, a supramolecular host (L-CD) with targeting function based on a β-cyclodextrin (β-CD) backbone was synthesized with carbonic anhydrase IX (CAIX) overexpressed on tumor cells as a target, and the methotrexate prodrug (MTX-SS-Ad) modified by adamantane and disulfide bond was prepared to be used as the guest. The amphiphilic complex was prepared between L-CD and MTX-SS-Ad through host-guest interactions and could further self-assemble into supramolecular nanoparticles (SNPs) with active targeting and stimulus release functions. The interaction between host and guest was investigated by UV, NMR, IR, XRD and TGA. The characteristic of SNPs was observed by DLS and TEM. Throng the study of molecular docking, in vitro inhibition, cell uptake experiments, and western blotting, SNPs have showed CAIX inhibitory effects both inside and outside the cells. The in vitro release experiments indicated that SNPs can undergo disintegration and release drugs under acidic and GSH conditions. Moreover, SNP can effectively inhibit the proliferation of cancer cells without generating additional toxic side effects on normal cells. So, we provide a strategy of bifunctional drug delivery system with targeting and glutathione-responsivity for effective tumor therapy.

Highly luminescent soft aggregates and films assembled by amphiphilic polyoxometalate complex in a polymerizable aprotic ionic liquid

Hybrid co-assembly from lanthanide-containing polyoxometalates (POMs) and surfactants could efficiently optimize the formed aggregate luminescent properties and structural diversity. Meanwhile, compared to conventional solvents, aprotic ionic liquids (ILs) are not only excellent assembly media but also ideal solvents for luminescent lanthanide compounds. Therefore, in this work, the luminescent amphiphilic POM complex, namely surfactant-encapsulated POM hybrid (SEP) was initially prepared mainly through electrostatic interaction from polyanionic lanthanide-containing POM, Na9(EuW10O36)·32H2O (EuW10) and cationic surfactant, 1-octadecyl-3-methylimidazolium bromide ([C18mim]Br, OB). Then, highly luminescent lamellar micro-fiber aggregates were assembled by SEP in a polymerizable imidazolium-IL solvent, i.e. 1-vinyl-3-butyl imidazolium terafluoroborate ([Vbim]BF4). After morphology and structure characterizations for soft aggregates in detail, a lamellar aggregation arrangement mechanism was proposed. Further through in situ photopolymerization for such aggregate matrices, the flexible and organized films with enhanced luminescent properties were obtained. Our work indicates that the rational design of polymerizable organized aggregate matrices in ILs could greatly improve the photophysical properties of such luminescent soft materials and also expand their practical applications.

Complexes of alkylated 1,4-diazabicyclo[2.2.2]octane with Ag(I) and Gd(III). Synthesis, self-association and biological activity

New amphiphilic surfactant-transition metal complexes [Ag(L)(NO3)2], [Ag(2L)(NO3)3] and [Gd(L)Br(NO3)3H2O] (where L is 1-cetyl-4-aza-1-azoniabicyclo[2.2.2]octane) were synthesized and characterized. The composition and 3D structure of the complexes were determined using IR and 1H NMR spectroscopy, elemental analysis, and X-ray diffractometry. Self-assembly and adsorption properties of the amphiphiles in an aqueous medium were studied by tensiometry, conductometry, potentiometry, dynamic and electrophoretic light scattering, transmission electron microscopy and fluorescence of pyrene. The Kraft temperature, the critical micelle concentration, the degree of bromide ion binding with aggregates, the aggregation numbers, the aggregate size, the zeta-potential of the systems, and the adsorption characteristics at the water–air interface were determined. The results obtained were compared with data for single ligand solutions and ligand-inorganic salt mixtures. A high aggregation capacity and morphological rearrangements in metallosurfactant solutions (vesicle-micelle transition) were established. The antimicrobial activity of metallosurfactants (including antibiotic-resistant strains), as well as low hemolytic and cytotoxic effects were shown, which allows them to be classified as potential drugs with a wide spectrum of activity.

Highly luminescent ultra-thin films with rare earth for plasmonic applications

Amphiphilic complexes with luminescent rare earth metal ions suitable for Lanmuir-Blodgett (LB) deposition have been synthesized. LB monolayers with closely packed Eu complexes deposited directly on silver demonstrate significant far-field emission in contrast to the theoretical predictions of full quenching. Angular radiation and polarization patterns of the electric and magnetic dipole emission of Eu3+ point to a high excitation efficiency of surface plasmon polaritons. Different luminescent behavior of closely packed emitters in comparison to diluted systems is tentatively attributed to the collective state of emitters in LB layers formed via near-field coupling with surface plasmons.

Relaxivity Enhancement of Hybrid Micelles via Modulation of Water Coordination Numbers for Magnetic Resonance Lymphography.

Considerable efforts have been made to develop nanoparticle-based magnetic resonance contrast agents (CAs) with high relaxivity. The prolonged rotational correlation time (τR) induced relaxivity enhancement is commonly recognized, while the effect of the water coordination numbers (q) on the relaxivity of nanoparticle-based CAs gets less attention. Herein, we first investigated the relationship between T1 relaxivity (r1) and q in manganese-based hybrid micellar CAs and proposed a strategy to enhance the relaxivity by increasing q. Hybrid micelles with different ratios of amphiphilic manganese complex (MnL) and DSPE-PEG2000 were prepared, whose q values were evaluated by Oxygen-17-NMR spectroscopy. Micelles with lower manganese doping density exhibit increased q and enhanced relaxivity, corroborating the conception. In vivo sentinel lymph node (SLN) imaging demonstrates that DSPE-PEG/MnL micelles could differentiate metastatic SLN from inflammatory LN. Our strategy makes it feasible for relaxivity enhancement by modulating q, providing new approaches for the structural design of high-performance hybrid micellar CAs.

Functionalized Amphiphilic Block Copolymers and Complex Emulsions for Selective Sensing of Dissolved Metals at Liquid-Liquid Interfaces.

Increasing contamination in potable water supplies necessitates the development of sensing methods that provide the speed and selectivity necessary for safety. One promising method relies on recognition and detection at the liquid-liquid interface of dynamic complex emulsions. These all-liquid materials transduce changes in interfacial tensions into optical signals via the coupling of their chemical, physical, and optical properties. Thus, to introduce selectivity, it is necessary to modify the liquid-liquid interface with an interfacially stable and selective recognition unit. To this end, we report the synthesis and characterization of amphiphilic block copolymers modified with metal chelators to selectively measure the concentrations of dissolved metal ions. We find that significant reduction in interfacial tensions arises upon quantitative addition of metal ions with high affinity toward functionalized chelators. Furthermore, measurements from UV-vis spectroscopy reveal that complexation of the block copolymers with metal ions leads to an increase in surface excess and surfactant effectiveness. We also demonstrate selective detection of iron(III) cations (Fe3+) on the μM levels even through interference from other mono-, di-, or trivalent cations in complex matrices of synthetic groundwater. Our results provide a unique platform that couples selective recognition and modulation of interfacial behaviors and demonstrates a step forward in the development of the multiplexed sensing device needed to deconvolute the complicated array of contaminants that comprise real-world environmental samples.

Efficient separation of IgG from IgM antibodies via conjugated surfactant micelles

Immunoglobulin-G (IgG) (∼150 kDa) antibodies confer longer term immunity against bacterial or viral infections than the heavier IgM’s (∼900 kDa), which are generally detectable in blood circulation in response to more recently acquired infections. There may be, however, a time overlap, which is problematic for diagnostic purposes, in the interests of which it is essential to separate IgM's from IgG’s. We describe a purification platform, functioning at pH 6.5, containing Tween-20, or Brij-O20, non-ionic detergent micelles, mixed with the sugar-rich detergent dodecyl maltoside (DDM), amino acid monomer tyrosine (Tyr), and conjugated by the amphiphilic complex [(bathophenanthroline)3: Fe2+]. Using conjugated Brij-O20 micelles, with input molar ratio IgG: IgM 9:1, IgG is recovered at 10 °C with 85–90% yield, (by SDS-PAGE densitometry) and ≥95% purity (also by SDS-PAGE), while IgM's are recovered at lower yields (28–34%) and contain small amounts of co-extracted IgG's. Addition of E. coli lysate as an artificial contamination background does not reduce the yield or purity of the recovered IgG. Tween-20/DDM/Tyr micelles lead to IgG purity ≥95% similar to that of Brij-O20, but with lower process yields (64–70%, by densitometry). Chromatographic separation with Protein A or Protein G resins leads to yields comparable to those obtained with Brij-O20 micelles, but with lower purity.

Light-Elicited and Oxygen-Saved Iridium Nanocapsule for Oxidative Damage Intensified Oncotherapy.

Regulating redox homeostasis in tumor cells and exploiting oxidative stress to damage tumors is an efficacious strategy for cancer therapy. However, the strengths of organic nanomaterials within this strategy are often ignored. In this work, a light-triggered reactive oxygen species (ROS) damaging nanoamplifier (IrP-T) was developed for enhanced photodynamic therapy (PDT). The IrP-T was fabricated with an amphiphilic iridium complex and a MTH1 inhibitor (TH287). Under green light stimulation, IrP-T catalyzed the oxygen in cells to generate ROS for realizing oxidative damage; meanwhile, TH287 increased the accumulation of 8-oxo-dGTP, further strengthening oxidative stress and inducing cell death. IrP-T could maximize the use of a small amount of oxygen, thus further boosting the efficacy of PDT in hypoxic tumors. The construction of nanocapsules provided a valuable therapeutic strategy for oxidative damage and synergizing PDT.

Biocomposite materials based on polyethylene and amphiphilic polymer-iron metal complex

Objectives. To obtain and study the properties including degradability of polymer composite materials (PCM) based on low-density polyethylene (LDPE) obtained by introducing an environmentally friendly additive comprising an oxo-decomposing additive (ODA) based on an amphiphilic polymer-iron metal complex, which accelerates the process of polymer degradation.Methods. PCMs based on LDPE and ODA were produced by processing in laboratory extruders in the form of strands, granules, and films. Thermodynamic properties were determined by differential scanning calorimetry in the temperature range 20-130 °C. In order to assess the performance characteristics (physical and mechanical properties) of the PCM, tensile strength and elongation at break were determined. The biodegradability of PCM was evaluated by Sturm's method, with the biodegradation index being determined by the amount of CO2 gas released as a result of microorganism activity, as well as composting by placing the PCMs for six months in biohumus. Changes in physical and mechanical properties and water absorption of the films during storage were evaluated. The photochemical degradability of the PCM was determined by exposing it to ultraviolet radiation for 100 h (equivalent to approximately one year of exposure of the films under natural conditions). The appearance of the composite samples following removal from the biohumus was determined using an optical microscope with ×50 magnification in transmitted and reflected light.Results. Following biodegradation by composting, the physical and mechanical properties of PCMs decrease by an average of 40.6%. This is related to the structural changes that occur in composites during storage in biohumus, i.e., the formation of a looser structure due to the development of large clusters of microorganisms that affect the formation of microcracks. It leads to the stage of fragmentation of the polyethylene matrix and indicates the progress of biological degradation of composites. In this case, the water absorption of the composite samples was 63% after 96 h of exposure. The biodegradability index determined by the Sturm method after 28 days of bubbling had changed by 82%, indicating an intensive biodegradation process. Exposure to ultraviolet radiation for 96 h resulted in the complete destruction of the PCMs, which turned into small “flakes.” This method is the most effective for the degradation of LDPE- and ODA-based PCMs.Conclusions. According to the results of the study of ODA-containing PCMs based on an amphiphilic polymer-iron metal complex, the tested filler-modifier can be recommended for the production of PCMs offering an accelerated degradation period.

Interfacial Polyelectrolyte Complexation-Inspired Bioprinting of Vascular Constructs

Bioprinting is a precise layer-by-layer manufacturing technology utilizing biomaterials, cells, and sometimes growth factors for the fabrication of customized three-dimensional (3D) biological constructs. In recent years, it has gained considerable interest in various biomedical studies. However, the translational application of bioprinting is currently impeded by the lack in efficient techniques for blood vessel fabrications. In this report, by systematically studying the previously reported phenomenon, interfacial polyelectrolyte complexation, an efficient blood vessel bioprinting technique based on the phenomenon, was proposed and subsequently investigated. In this technique, anionic hyaluronate and cationic lysine-based peptide amphiphiles were placed concentrically to bioprint with human umbilical endothelial cells for the fabrication of biological tubular constructs. These constructs demonstrated clear vascular features, which made them highly resemble blood vessels. In addition, to optimize the bioactivity of the printed constructs, this report also, for the first time, studied peptide sequencing's effect on the biocompatibility of the polyelectrolyte-peptide amphiphile complex. All these studies conducted in the report are highly relevant and interesting for research in vascular structure fabrication, which will eventually be beneficial for translational application development of bioprinting.

Pickering emulsions stabilized by β-CD microcrystals: Construction and interfacial assembly mechanism.

β-Cyclodextrin (β-CD) can combine with oil and other guest molecules to form amphiphilic inclusion complexes (ICs), which can be adsorbed on the oil-water interface to reduce the interfacial tension and stabilize Pickering emulsions. However, the subtle change of β-CD in the process of emulsion preparation is easily ignored. In this study, β-CD and ginger oil (GO) were used to prepare the Pickering emulsion by high-speed shearing homogenization without an exogenous emulsifier. The stability of the emulsion was characterized by microscopic observation, staining analysis, and creaming index (CI). Results showed that the flocculation of the obtained Pickering emulsion was serious, and the surface of the droplets was rough with lamellar particles. In order to elucidate the formation process of the layered particles, the GO/β-CD ICs were further prepared by ball milling method, and the X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and interfacial tension analyses found that β-CD and GO first formed amphiphilic nanoscale small particles (ICs) through the host-guest interaction, and the formed small particles were further self-assembled into lamellar micron-scale amphiphilic ICs microcrystals. These amphiphilic ICs and microcrystals aggregated at the oil-water interface and finally formed the Pickering emulsion. In this study, by exploring the formation process and evolution of GO/β-CD self-assembly, the formation process and stabilization mechanism of the β-CD-stabilized GO Pickering emulsion were clarified preliminarily, with the aim of providing a theoretical basis for the development of high-performance CD-stabilized Pickering emulsions.

Recent Advancements and Applications of Phospholipid Complexes: A Strategy to Enhancing the Bioavailability of Phytopharmaceuticals

Abstract: Phytopharmaceuticals are herbal medicines that include standardized extracts, bioactive fractions, and purified phytoconstituents. They have been used for the cure, treatment, and mitigation of diseases since ancient times. Phytopharmaceuticals have a wide array of health benefits but their therapeutic efficacy is limited due to poor absorption, low bioavailability, and early elimination profile. A novel phospholipid complex is a newly introduced patented technology initially developed to incorporate standardized plant extracts/fractions or water-soluble phytoconstituents into phospholipids to produce a lipid compatible molecular complex, called phytosome, which improves their absorption and bioavailability. In herbal formulations, phytosome is the most advanced dosage form that has upgraded absorption rate and improved pharmacokinetics in comparison with conventional products. Phospholipid-complex is the result of hydrogen bonding between phospholipids and phytoconstituents, which offers maximum incorporation of herbal active ingredients into the lipidic layer and core. The increased therapeutic efficacy is due to the formation of amphiphilic phospholipid complex of herbal medicine. This review highlights the role of phospholipids in the delivery of herbal bioactives and natural extracts with special emphasis on phytosomes. Moreover, the current status of bioavailabilities, commercial products, patents, and clinical trials of phytosomal system of phytopharmaceuticals were addressed.

Liposomal MRI probes containing encapsulated or amphiphilic Fe(III) coordination complexes.

Liposomes containing high-spin Fe(III) coordination complexes were prepared towards the production of T1 MRI probes with improved relaxivity. The amphiphilic Fe(III) complexes were anchored into the liposome with two alkyl chains to give a coordination sphere containing mixed amide and hydroxypropyl pendant groups. The encapsulated complex contains a macrocyclic ligand with three phosphonate pendants, [Fe(NOTP)]3-, which was chosen for its good aqueous solubility. Four types of MRI probes were prepared including those with intraliposomal Fe(III) complex (LipoA) alone, amphiphilic Fe(III) complex (LipoB), both intraliposomal and amphiphilic complex (LipoC) or micelles formed with amphiphilic complex. Water proton relaxivities r1 and r2 were measured and compared to a small molecule macrocyclic Fe(III) complex containing similar donor groups. Micelles of the amphiphilic Fe(III) complex had proton relaxivity values (r1 = 2.6 mM-1 s-1) that were four times higher than the small hydrophilic analog. Liposomes with amphiphilic Fe(III) complex (LipoB) have a per iron relaxivity of 2.6 mM-1 s-1 at pH 7.2, 34 °C at 1.4 T whereas liposomes containing both amphiphilic and intraliposomal Fe(III) complexes (lipoC) have r1 of 0.58 mM-1 s-1 on a per iron basis consistent with quenching of the interior Fe(III) complex relaxivity. Liposomes containing only encapsulated [Fe(NOTP)]3- have a lowered r1 of 0.65 mM-1 s-1 per iron complex. Studies show that the biodistribution and clearance of the different types liposomal nanoparticles differ greatly. LipoB is a blood pool agent with a long circulation time whereas lipoC is cleared more rapidly through both renal and hepatobiliary pathways. These clearance differences are consistent with lower stability of LipoC compared to LipoB.

Synthesis of amphiphilic chiral salen complexes and their conformational manipulation at the air-water interface.

A series of amphiphilic salen complexes, [L1a,bM] and [L2a,bM], were designed and synthesized. These complexes consist of two or four hydrophilic triethylene glycol (TEG) chains and a hydrophobic π-extended metallosalen core based on naphthalene or phenanthrene. The obtained amphiphilic complexes, [L1bM] (M = Ni, Cu, Zn), formed a monolayer at the air-water interface, while the monocationic [L1bCo(MeNH2)2](OTf) did not form a well-defined monolayer. The number of hydrophilic TEG chains also had an influence on the monolayerformation behavior; the tetra-TEG derivatives, [L1bNi] and [L2bNi], showed a pressure rise at a less compressed region than the bis-TEG derivatives, [L1aNi] and [L2aNi]. In addition, the investigation of their compressibility and compression modulus suggested that the tetra-TEG derivatives, [L1bNi] and [L2bNi], are more flexible than the corresponding bis-TEG analogues, [L1aNi] and [L2aNi], and that the phenanthrene derivatives [L1a,bNi] were more rigid than the corresponding naphthalene analogues, [L2a,bNi]. The Langmuir-Blodgett (LB) films of one of the complexes, [L1bNi], showed CD spectra slightly different from that in solution, which may originate from the unique anisotropic environment of the air-water interface. Thus, we demonstrated the possibility of controlling the chiroptical properties of metal complexes by mechanical compression.

Chemically-assisted DNA transfection methods: An overview

Non-viral chemical-based methods for in vitro cell transfection are commonly used to incorporate foreign gene of interest into mammalian cells due to numerous benefits ? high efficiency, low cost and simple methodology. These powerful transfection methods generally do not possess safety risks as virus-based, and cell toxicity is significantly reduced. To obtain transfectants, host cells are usually treated with biocompatible DNA carriers such as calcium phosphate, cationic lipids, DEAE-dextran, polyethylenimine or dendrimers, classifying these methods based on chemical reagents used. All these different approaches are based on the similar principle, namely formation of encapsulated amphiphilic complexes between DNA and various particles, following cell uptake, most likely mediated by endocytosis. Depending on the aim and design of experiment, the choice of appropriate method is made. This review article outlines strategies of the most widely used chemical transfection techniques, pointing out advantages and limitations of different DNA carriers, also findings of researchers as how to optimize and enhance efficiency of gene delivery procedure. With methodology constantly being improved, transfection methods described here find their main, biomedical application in gene therapy, a promising way to introduce functional copy of exogenous gene to genetically defective target cells.