N-[4-(N,N,N-trimethylammonium)benzyl]chitosan chloride: Synthesis, interaction with DNA and evaluation of transfection efficiency

Hyaluronan/B12-chitosan polyelectrolyte complex for oral colistin administration

Polyelectrolyte complexes (PECs) based on polysaccharides, including hyaluronic acid (HA) and chitosan (CS), are promising delivery systems for antimicrobial agents, including oral administration of the peptide antibiotic colistin (CT). Modification of CS with different targeting ligands to improve intestinal permeability is a suitable way to improve the oral bioavailability of polyelectrolyte particles. This study describes the procedure for obtaining CT-containing PECs based on HA and CS modified with cyanocobalamin (vitamin B12). In this case, vitamin B12 is used as a targeting ligand because it is absorbed in the ileum via specific transporter proteins. The resulting PECs had a hydrodynamic size of about 284 nm and a positive ζ-potential of about 26 mV; the encapsulation efficiency was 88.2 % and the CT content was 42.2 μg/mg. The developed systems provided a two-phase drug release: about 50 % of the CT was released in 0.5-1 h, and about 60 % of the antibiotic was cumulatively released in 5 h. The antimicrobial activity of encapsulated CT was maintained at the same level as the pure drug for at least 24 h (minimum inhibitory concentration against Pseudomonas aeruginosa was 2 μg/mL for both). In addition, the apparent permeability coefficient of CT in the PEC formulation was 2.4 × 10-6 cm/s. Thus, the incorporation of CT into HA- and vitamin B12-modified CS-based PECs can be considered as a simple and convenient method to improve the oral delivery of CT.

Development and Bioactivity of Zinc Sulfate Cross-Linked Polysaccharide Delivery System of Dexamethasone Phosphate

Improving the biopharmaceutical properties of glucocorticoids (increasing local bioavailability and reducing systemic toxicity) is an important challenge. The aim of this study was to develop a dexamethasone phosphate (DexP) delivery system based on hyaluronic acid (HA) and a water-soluble cationic chitosan derivative, diethylaminoethyl chitosan (DEAECS). The DexP delivery system was a polyelectrolyte complex (PEC) resulting from interpolymer interactions between the HA polyanion and the DEAECS polycation with simultaneous incorporation of zinc ions as a cross-linking agent into the complex. The developed PECs had a hydrodynamic diameter of 244 nm and a ζ-potential of +24.4 mV; the encapsulation efficiency and DexP content were 75.6% and 45.4 μg/mg, respectively. The designed DexP delivery systems were characterized by both excellent mucoadhesion and prolonged drug release (approximately 70% of DexP was released within 10 h). In vitro experiments showed that encapsulation of DexP in polysaccharide nanocarriers did not reduce its anti-inflammatory activity compared to free DexP.

Succinyl Chitosan-Colistin Conjugates as Promising Drug Delivery Systems

The growth of microbial multidrug resistance is a problem in modern clinical medicine. Chemical modification of active pharmaceutical ingredients is an attractive strategy to improve their biopharmaceutical properties by increasing bioavailability and reducing drug toxicity. Conjugation of antimicrobial drugs with natural polysaccharides provides high efficiency of these systems due to targeted delivery, controlled drug release and reduced toxicity. This paper reports a two-step synthesis of colistin conjugates (CT) with succinyl chitosan (SucCS); first, we modified chitosan with succinyl anhydride to introduce a carboxyl function into the polymer molecule, which was then used for chemical grafting with amino groups of the peptide antibiotic CT using carbodiimide chemistry. The resulting polymeric delivery systems had a degree of substitution (DS) by CT of 3-8%, with conjugation efficiencies ranging from 54 to 100% and CT contents ranging from 130-318 μg/mg. The size of the obtained particles was 100-200 nm, and the ζ-potential varied from -22 to -28 mV. In vitro release studies at pH 7.4 demonstrated ultra-slow hydrolysis of amide bonds, with a CT release of 0.1-0.5% after 12 h; at pH 5.2, the hydrolysis rate slightly increased; however, it remained extremely low (1.5% of CT was released after 12 h). The antimicrobial activity of the conjugates depended on the DS. At DS 8%, the minimum inhibitory concentration (MIC) of the conjugate was equal to the MIC of native CT (1 µg/mL); at DS of 3 and 5%, the MIC increased 8-fold. In addition, the developed systems reduced CT nephrotoxicity by 20-60%; they also demonstrated the ability to reduce bacterial lipopolysaccharide-induced inflammation in vitro. Thus, these promising CT-SucCS conjugates are prospective for developing safe and effective nanoantibiotics.

The first selenium containing chitin and chitosan derivatives: Combined synthetic, catalytic and biological studies

Ultrasonic approach to the synthesis of the first selenium-containing derivatives of chitin and chitosan has been developed. The synthetic procedure is simple, provides high yields, does not require harsh conditions, and uses water as the reaction medium. The elaborated chitin and chitosan derivatives and their based nanoparticles are non-toxic and possess high antibacterial and antifungal activity. Their antimicrobial activity exceeds the effect of the classic antibiotics (Ampicillin and Gentamicin) and the antifungal drug Amphotericin B. The obtained selenium-containing cationic chitin and chitosan derivatives exhibit a high transfection activity and are promising gene delivery vectors. Nanoparticles of the synthesized polymers are highly efficient catalysts for the oxidation of 1-phenylethyl alcohol to acetophenone by bromine at room temperature.

A novel low-molecular-weight chitosan/gamma-polyglutamic acid polyplexes for nucleic acid delivery into zebrafish larvae

Many challenges, such as virus infection, extreme weather and long cultivation periods, during the development of fish larvae have been observed, especially in aquaculture. Gene delivery is a useful method to express functional genes to defend against these challengers. However, the methods for fish larvae are insufficient. In our earlier report, low-molecular-weight chitosan (LMWCS) showed a strong positive charge and may be useful for polyplex formulation. Herein, we present a simple self-assembly of LMWCS polyplexes (LMWCSrNPs) for gene delivery into zebrafish larvae. Different weight ratios of LMWCS/gamma-polyglutamic acid (γ-PGA)/plasmid DNA were analyzed by gel mobility assay. Delivery efficiency determined by green fluorescent protein (GFP) expression in zebrafish liver (ZFL) cells showed that delivery efficiency at a weight ratio of 20:8:1 was higher than others. Zeta potential and transmission electron microscopy (TEM) analysis showed that the round shape of the particle size varied. In our earlier reports, IRF9S2C could induce interferon-stimulated gene (ISG) expression to induce innate immunity in zebrafish and pufferfish. Further delivery of pcDNA3-IRF9S2C-HA plasmid DNA into ZFL cells and zebrafish larvae by LMWCSrNP successfully induced ISG expression. Collectively, LMWCSrNP could be a novel gene delivery system for zebrafish larvae and might be used to improve applications in aquaculture.

Synthesis and Characterization of Novel Succinyl Chitosan-Dexamethasone Conjugates for Potential Intravitreal Dexamethasone Delivery

The development of intravitreal glucocorticoid delivery systems is a current global challenge for the treatment of inflammatory diseases of the posterior segment of the eye. The main advantages of these systems are that they can overcome anatomical and physiological ophthalmic barriers and increase local bioavailability while prolonging and controlling drug release over several months to improve the safety and effectiveness of glucocorticoid therapy. One approach to the development of optimal delivery systems for intravitreal injections is the conjugation of low-molecular-weight drugs with natural polymers to prevent their rapid elimination and provide targeted and controlled release. This study focuses on the development of a procedure for a two-step synthesis of dexamethasone (DEX) conjugates based on the natural polysaccharide chitosan (CS). We first used carbodiimide chemistry to conjugate DEX to CS via a succinyl linker, and we then modified the obtained systems with succinic anhydride to impart a negative ζ-potential to the polymer particle surface. The resulting polysaccharide carriers had a degree of substitution with DEX moieties of 2–4%, a DEX content of 50–85 μg/mg, and a degree of succinylation of 64–68%. The size of the obtained particles was 400–1100 nm, and the ζ-potential was −30 to −33 mV. In vitro release studies at pH 7.4 showed slow hydrolysis of the amide and ester bonds in the synthesized systems, with a total release of 8–10% for both DEX and succinyl dexamethasone (SucDEX) after 1 month. The developed conjugates showed a significant anti-inflammatory effect in TNFα-induced and LPS-induced inflammation models, suppressing CD54 expression in THP-1 cells by 2- and 4-fold, respectively. Thus, these novel succinyl chitosan-dexamethasone (SucCS-DEX) conjugates are promising ophthalmic carriers for intravitreal delivery.

Hyaluronan/Diethylaminoethyl Chitosan Polyelectrolyte Complexes as Carriers for Improved Colistin Delivery

Improving the therapeutic characteristics of antibiotics is an effective strategy for controlling the growth of multidrug-resistant Gram-negative microorganisms. The purpose of this study was to develop a colistin (CT) delivery system based on hyaluronic acid (HA) and the water-soluble cationic chitosan derivative, diethylaminoethyl chitosan (DEAECS). The CT delivery system was a polyelectrolyte complex (PEC) obtained by interpolymeric interactions between the HA polyanion and the DEAECS polycation, with simultaneous inclusion of positively charged CT molecules into the resulting complex. The developed PEC had a hydrodynamic diameter of 210-250 nm and a negative surface charge (ζ-potential = -19 mV); the encapsulation and loading efficiencies were 100 and 16.7%, respectively. The developed CT delivery systems were characterized by modified release (30-40% and 85-90% of CT released in 15 and 60 min, respectively) compared to pure CT (100% CT released in 15 min). In vitro experiments showed that the encapsulation of CT in polysaccharide carriers did not reduce its antimicrobial activity, as the minimum inhibitory concentrations against Pseudomonas aeruginosa of both encapsulated CT and pure CT were 1 μg/mL.

N-[4-(N,N,N-Trimethylammonium)Benzyl]Chitosan Chloride as a Gene Carrier: The Influence of Polyplex Composition and Cell Type

Polyplex-based gene delivery systems are promising substitutes for viral vectors because of their high versatility and lack of disadvantages commonly encountered with viruses. In this work, we studied the DNA polyplexes with N-[4-(N,N,N-trimethylammonium)benzyl]chitosan chloride (TMAB-CS) of various compositions in different cell types. Investigations of the interaction of TMAB-CS with DNA by different physical methods revealed that the molecular weight and the degree of substitution do not dramatically influence the hydrodynamic properties of polyplexes. Highly substituted TMAB-CS samples had a high affinity for DNA. The transfection protocol was optimized in HEK293T cells and achieved the highest efficiency of 30-35%. TMAB-CS was dramatically less effective in nonadherent K562 cells (around 1% transfected cells), but it was more effective and less toxic than polyarginine.

Water-soluble triazole chitin derivative and its based nanoparticles: Synthesis, characterization, catalytic and antibacterial properties

In this work, we treated chitin with 2-(azidomethyl)oxirane and successfully involved the resultant azido chitin derivatives in the ultrasound-assisted Cu(I)-catalyzed azido-alkyne click (CuAAC) reaction with propargylic ester of N,N,N-trimethyl glycine. Thus, we obtained novel water-soluble triazole chitin derivatives. The triazole chitin derivatives and their nanoparticles are characterized by a high in vitro antibacterial activity, which is the same or even higher than that of commercial antibiotics ampicillin and gentamicin. The obtained derivatives are non-toxic. Moreover, the obtained water-soluble polymers are highly efficient green catalysts for the aldol reaction in green solvent water. The catalysts can be easily extracted from the reaction mixture by its precipitation with green solvent ethanol followed by centrifugation and they can be reused at least 10 times.

New water-soluble chitin derivative with high antibacterial properties for potential application in active food coatings

The synthesis of new chitin derivatives through ultrasound-assisted treatment of the chitin with 1-azido-3-chloropropan-2-ol under Green Chemistry conditions is described. This is the first example of ultrasound-assisted polymer analogues transformation of chitin unaccompanied by noticeable backbone degradation or deacetylation. The obtained water-soluble azido chitin derivatives are characterized by high antibacterial activity, which is comparable with that of commercial antibiotics ampicillin and gentamicin. At the same time, they were demonstrated almost identical in vitro toxicity as unmodified chitin and chitosan. The antibacterial activity of the obtained polymers is mainly provided by azido moiety in their macromolecules. The conjugation of azido moiety to chitin backbone strongly diminishes the toxicity of the azido pharmacophore, but preserves its antibacterial properties. The most potent chitin derivative was used for the film coating of Ricotta cheese samples. This food coating proved to be efficient for the prolongation of shelf life of Ricotta cheese.

New water-soluble derivatives of chitin and their based nanoparticles: Antibacterial and catalytic activity

A facile route towards new chitin derivatives with both catalytical and biological activities is proposed in the course of methodology development aimed at the design of polyfunctional materials on the basis of renewable and accessible natural polysaccharides. Ultrasound-promoted and Cu(I)-catalyzed azido-alkyne click cycloaddition of the propargylic ester of nicotinic acid and its N-methylated analogue to the azido chitin derivative allowed us to obtain previously unknown non-toxic water-soluble derivatives of chitin. The obtained polymers and their based nanoparticles demonstrated a high antibacterial activity in vitro, which is comparable or even superior to that of commercial antibiotics ampicillin and gentamicin. New derivatives of chitin were also shown to be highly efficient and reusable (at least for 10 times) green catalysts for the aldol reaction in water. The catalysts can be easily separated from the reaction mixture by their precipitation with ethanol. The results obtained highlight prospects of further studies on chitin's application in the rational design of novel functional materials with valuable properties.

Chitosan derivatives and their based nanoparticles: ultrasonic approach to the synthesis, antimicrobial and transfection properties

In the present work, we demonstrate that alkylation of chitosan by alkyl halides, aza-Michael reaction with chitosan, and Ad_N-E reaction of chitosan with aldehydes can be efficiently mediated by ultrasound. An optimization of ultrasonic irradiation parameters allowed us to (i) accelerate the rate of the reactions dramatically, (ii) achieve high selectivity, and (iii) preserve integrity of the polysaccharide backbone avoiding its depolymerization. We evaluated antibacterial/antifungal and transfection activity of 8 different derivatives of chitosan and their based nanoparticles in vitro. Moreover, we studied antibacterial activity of the most efficient polymer and their based nanoparticles in vivo. The tested polymer proved to be superior to reference commercial antibiotics ampicillin and gentamicin.

Effect of Double Substitution in Cationic Chitosan Derivatives on DNA Transfection Efficiency

Recently, much effort has been expended on the development of non-viral gene delivery systems based on polyplexes of nucleic acids with various cationic polymers. Natural polysaccharide derivatives are promising carriers due to their low toxicity. In this work, chitosan was chemically modified by a reaction with 4-formyl-n,n,n-trimethylanilinium iodide and pyridoxal hydrochloride and subsequent reduction of the imine bond with NaBH₄. This reaction yielded three novel derivatives, n-[4-(n’,n’,n’-trimethylammonium)benzyl]chitosan chloride (TMAB-CS), n-[(3-hydroxy-5-(hydroxymethyl)-2-methyl-4-pyridine)methyl]chitosan chloride (Pyr-CS), and n-[4-(n’,n’,n’’-trimethylammonium)benzyl]-n-[(3-hydroxy-5-(hydroxymethyl)-2-methyl-4-pyridine)methyl]chitosan chloride (PyrTMAB-CS). Their structures and degrees of substitution were established by ¹H NMR spectroscopy as DS₁ = 0.22 for TMAB-CS, DS₂ = 0.28 for Pyr-CS, and DS₁ = 0.21, DS₂ = 0.22 for PyrTMAB-CS. Dynamic light scattering measurements revealed that the new polymers formed stable polyplexes with plasmid DNA encoding the green fluorescent protein (pEGFP-N3) and that the particles had the smallest size (110–165 nm) when the polymer:DNA mass ratio was higher than 5:1. Transfection experiments carried out in the HEK293 cell line using the polymer:DNA polyplexes demonstrated that Pyr-CS was a rather poor transfection agent at polymer:DNA mass ratios less than 10:1, but it was still more effective than the TMAB-CS and PyrTMAB-CS derivatives that contained a quaternary ammonium group. By contrast, TMAB-CS and PyrTMAB-CS were substantially more effective than Pyr-CS at higher polymer:DNA mass ratios and showed a maximum efficiency at 200:1 (50%–70% transfected cells). Overall, the results show the possibility of combining substituent effects in a single carrier, thereby increasing its efficacy.

Mucoadhesive cholesterol-chitosan self-assembled particles for topical ocular delivery of dexamethasone

The topical application of ophthalmic drugs is a convenient and safe mode of drug administration. However, the bioavailability of topical drugs in the eye is low due to eye barriers and the rapid removal of the drug from the conjunctival surface by the tear fluid. The aim of this study was to obtain dexamethasone-loaded mucoadhesive self-assembled particles based on a conjugate of succinyl cholesterol with chitosan (SC-CS) for potential use as a topical ocular formulation. SC-CS was obtained via a carbodiimide-mediated coupling reaction (degree of substitution DS 1.2-5.8%). SC-CS in the DS range of 1.2-3.0% can self-organize in solution to form positively charged particles (ζ-potential 20-37 mV) of submicron size (hydrodynamic diameter 700-900 nm). The SC-CS particles show good mucoadhesiveness, which decreases with increasing DS. The obtained particles can encapsulate 159-170 μg/mg dexamethasone; they release about 50% of drug in 2 h, and the cumulative drug release reached 95% in 24 h. A cell model confirmed that dexamethasone-loaded SC-CS particles are non-cytotoxic and exhibit a comparable anti-inflammatory activity to that of pure dexamethasone. Testing the osmotic resistance of erythrocytes showed that both dexamethasone-loaded and non-loaded SC-CS particles have greater membrane-stabilizing ability than that of dexamethasone.

Polyplexes for gene and nucleic acid delivery: Progress and bottlenecks

Gene and nucleic acid delivery constitute a huge biological challenge and several attempts have been made by research laboratories to address this issue. Cationic polymers and cationic lipids (positively charged carriers) can be utilized for the transport of these biomolecules. Polyplexes (PPs) are interpolyelectrolyte complexes which are spontaneously formed through the electrostatic condensation between nucleic acid and a cationic polymer. PPs are capable of high-density payload condensation leading to cell internalization and subsequent protection from enzymatic degradation. Most cationic polymers can cross extracellular barriers, but it is more challenging to overcome intracellular barriers (efficient disassembly and endosomal escape). In this review, the use of PPs for gene and nucleic acid delivery is discussed.

Ca2+ signaling modulation using cancer cell membrane coated chitosan nanoparticles to combat multidrug resistance of cancer

Off-target drug delivery, together with multidrug resistance (MDR), are two keys obstacles that account for the disappointing outcome in clinical chemotherapy of cancer. To solve these dilemmas, Herein, we constructed cancer cell membrane (CCM) modified silica (CS) nanoparticles (CCM/CS) to co-deliver Ca²⁺ channel siRNA with doxorubicin (DOX) to construct a platform (CCM/CS/R-D) for the efficient therapy of cervical cancer. It was demonstrated that the optimal CCM/CS/R-D was spherical nanoparticles with size at 122.39 ± 4.69 nm and the surface charge of -27.76 ± 3.12 mV. In addition, the CCM/CS/R-D showed acid responsive drug release while high stability under physiological conditions with negligible hemolysis. The CCM/CS/R-D showed CCM mediated cellular uptake and efficient endosomal escape as well as siRNA transfection potential (comparable to that of PEI 25 K) on MDR cervical cancer cells (HeLa/DOX). Most importantly, the MDR of cancer cells was conquered through modulation of T-type Ca²⁺ (Cav) channels. It was observed that the Cav channel siRNA could negatively regulate the level of cytosolic Ca²⁺ concentration which triggered G0/G1 phase cell cycle arrest and elevated intracellular drug retention in HeLa/DOX cells without significantly affect the expression of P-glycolprotein (P-gp). The in vitro and in vivo experiments revealed that CCM/CS/R-D exerted greatly enhanced tumor targetability and therapeutic effect on HeLa/DOX, which was superior than CS/R-D or mono delivery system (CCM/CS/R or CCM/CS/D).

Ultrasound-assisted catalyst-free thiol-yne click reaction in chitosan chemistry: Antibacterial and transfection activity of novel cationic chitosan derivatives and their based nanoparticles

In this work, we demonstrate that the thiol-yne click reaction could be efficiently mediated by ultrasonic irradiation and implement the ultrasound-assisted thiol-yne click reaction to chitosan chemistry as a polymer-analogous transformation. We optimize power and frequency of ultrasound to preserve selectivity of the click reaction and avoid ultrasonic degradation of the chitosan polymer chain. Thus, we obtain a new water-soluble betaine. Using ionic gelation of the obtained betaine derivatives of chitosan, we prepare nanoparticles with a unimodal size distribution. Furthermore, we present results of antibacterial and transfection activity tests for the chitosan derivatives and their based nanoparticles. The derivative with a medium molecular weight and a high degree of substitution demonstrated the best antibacterial effect. It derived nanoparticles with a size of ca. 100 nm and ζ-potential of ca. +69 mV revealed even higher antibacterial activity, slightly superior to commercial antibiotics ampicillin and gentamicin. On the contrary, the obtained polymers possess a much more pronounced transfection activity as compared with their based nanoparticles and species with a low degree of substitution acts as the most efficient transfecting agent. Moreover, the obtained betaine chitosan derivatives as well as their derived nanoparticles are non-toxic.

Tailor-made ternary nanopolyplexes of thiolated trimethylated chitosan with pDNA and folate conjugated cis-aconitic amide-polyethylenimine for efficient gene delivery

To overcome the different extra-/intracellular barriers in gene delivery, tumor-targeted and pH/redox-responsive ternary polyplexes with charge-conversional properties were prepared through a modular self-assembly strategy. Firstly, the thiolated trimethylated chitosan (TMC-SH) was synthesized to crosslink and condense pDNA through electrostatic interaction and disulfide formation, which obtained the TMC-SS/pDNA binary polyplexes with redox-responsive gene release. To further endow the binary polyplexes with tumor targeting and endo/lysosomal pH-triggered charge-reversal properties, a folate conjugated cis-aconitic amide-polyethylenimine (FA-PEI-AcO) was synthesized to shield the positive TMC-SS/pDNA, generating the FA-PEI-AcO/TMC-SS/pDNA ternary polyplexes with a size of ~190 nm and negative surface-charges. The ζ-potential of the polyplexes was stable at physiological pH and increased rapidly from -14 mV to + 20 mV at pH 5.5 (endo/lysosomal pH) due to the breakages of acid-liable amide bonds and the subsequent de-shielding of FA-PEI-AcO layers, which might benefit the endo/lysosomal escape of the polyplexes. Afterward, the polyplexes could redox-responsively release gene at higher intracellular concentrations of glutathione. By taking advantage of such multi-responses, significantly enhanced transfection efficiency was achieved in vitro in Hela cells for the ternary polyplexes. These results suggested that the newly developed polyplexes had potential application for gene delivery.

Fabrication of Ion-Crosslinking Aminochitosan Nanoparticles for Encapsulation and Slow Release of Curcumin

Curcumin (Cur) has anticancer activities but has poor stability, which can be improved using carrier materials. In this study, chitosan was aminated to increase the number of amino groups on its surface, modified with folic acid (FA), and then made into nanoparticles by ionic crosslinking. Owing to ion interaction, the negatively charged, non-toxic tripolyphosphate (TPP) interacted with the positively charged amino group on the aminated chitosan (AmCS) surface, producing FA-AmCS-TPP nanoparticles, which were then characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrophotometry (FT-IR), and thermogravimetric analysis (TGA). Their small particle size (175.2 ± 0.99 nm) and good surface positive potential (+42.4 mV) are beneficial for carrying antitumor drugs. We subsequently investigated whether coating of Cur by AmCS allows slow drug release by FA-AmCS-TPP nanoparticles in different pH environments, and estimated the Cur loading efficiency (EE-Cur). Our results showed that the cumulative release rate of Cur at 48 h was 56.2%, and that the EE-Cur reached 94.26 ± 0.91% with nanoparticles composed of 0.10 g AmCS, 10.0 mg FA, 10.0 mg TPP, and 15.0 mg Cur. Additionally, cytotoxicity experiments showed that the Cur/FA-AmCS-TPP nanoparticles had good targeting ability for tumor cells. Therefore, the non-toxic targeted composite nanoparticles had potential as a new antitumor agent that can overcome the limitations of Cur.

Ultrasound-assisted Cu(I)-catalyzed azide-alkyne click cycloaddition as polymer-analogous transformation in chitosan chemistry. High antibacterial and transfection activity of novel triazol betaine chitosan derivatives and their nanoparticles

In this work, we involved ultrasound-assisted click CuAAC in chitosan chemistry. Ultrasound-mediated CuAAC between propargylic ester of betaine and azido chitosan derivative proceeds fast in water under aerobic conditions and gives rise novel water-soluble triazole betaine chitosan derivatives. Using ionic gelation technique, we prepared and characterized nanoparticles from the synthesized chitosan derivatives. We studied antibacterial and transfection activity of the novel chitosan derivatives and their nanoparticles. The nanoparticles with size ca. 100 nm and ζ-potential ca. +65 mV proved to possess outstanding antibacterial activity, which is much more than that of the triazole betaine derivatives in their native form, and it is equal to the activity of ampicillin and gentamicin. Opposite, triazole betaine chitosan derivatives in their native form are characterized by remarkable transfection activity as compared with their nanoparticles. The most active triazole betaine chitosan derivatives are derivatives of moderate molecular weight with moderate degree of substitution. Their transfection activity is extremely high for chitosan species and it is comparable (values of the same order) with activity of Lipofectin - commercially available gene delivery vector.

Chitosan for gene delivery: Methods for improvement and applications

Gene therapy is a promising strategy for treating challenging diseases. The successful delivery of genes is a critical step for gene therapy. However, concerns about immunogenicity and toxicity are the main obstacles against the widespread use of effective viral systems. Therefore, nonviral vectors are regarded as good alternatives to viral vectors. Chitosan is a natural cationic polysaccharide that could be used to create nonviral gene delivery vectors. Various methods have been developed to improve the properties of chitosan related to gene delivery. This review introduces the features of chitosan in gene delivery, summarizes current progress toward methods promoting the properties of chitosan related to gene delivery, and presents different applications of chitosan in gene delivery vectors. Finally, future prospects of gene vectors based on chitosan are discussed.

Comparative Study of Diethylaminoethyl-Chitosan and Methylglycol-Chitosan as Potential Non-Viral Vectors for Gene Therapy

In this paper, we compared the transfection efficiency and cytotoxicity of methylglycol-chitosan (MG-CS) and diethylaminoethyl-chitosan (DEAE-CS_I and DEAE-CS_II with degrees of substitution of 1.2 and 0.57, respectively) to that of Lipofectamine (used as a reference transfection vector). MG-CS contains quaternary amines to improve DNA binding, whereas the DEAE-CS exhibits pH buffering capability that would ostensibly enhance transfection efficiency by promoting endosomal escape. Gel retardation assays showed that both DEAE-CS and MG-CS bound to DNA at a polysaccharide:DNA mass ratio of 2:1. In Calu-3 cells, the DNA transfection activity was significantly better with MG-CS than with DEAE-CS, and the efficiency improved with increasing polysaccharide:DNA ratios. By contrast, the efficiency of DEAE-CS_I and DEAE-CS_II was independent of the polysaccharide:DNA ratio. Conversely, in the transfection-recalcitrant JAWSII cells, both Lipofectamine and MG-CS showed significantly lower DNA transfection activity than in Calu-3 cells, whereas the efficiency of DEAE-CS_I and DEAE-CS_II was similar in both cell lines. The toxicity of DEAE-CS increased with increasing concentrations of the polymer and its degree of substitution, whereas MG-CS demonstrated negligible cytotoxicity, even at the highest concentration studied. Overall, MG-CS proved to be a more efficient and less toxic transfection agent when compared to DEAE-CS.