Polysaccharide colloidal particles as delivery systems for macromolecules

Nanoparticles and Colloidal Hydrogels of Chitosan-Caseinate Polyelectrolyte Complexes for Drug-Controlled Release Applications

Chitosan–caseinate nanoparticles were synthesized by polyelectrolyte complex (PEC) formation. Caseinate is an anionic micellar nanocolloid in aqueous solutions, which association with the polycationic chitosan yielded polyelectrolyte complexes with caseinate cores surrounded by a chitosan corona. The pre-structuration of caseinate micelles facilitates the formation of natural polyelectrolyte nanoparticles with good stability and sizes around 200 nm. Such natural nanoparticles can be loaded with molecules for applications in drug-controlled release. In the nanoparticles processing, parameters such as the chitosan degree of acetylation (DA) and molecular weight, order of addition of the polyelectrolytes chitosan (polycation) and caseinate (polyanion), and added weight ratio of polycation:polyanion were varied, which were shown to influence the structure of the polyelectrolyte association, the nanoparticle size and zeta potential. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) analyses revealed the chemical structure of hydrogel colloidal systems consisting of nanoparticles that contain chitosan and caseinate. Transmission electron microscopy (TEM) allowed further characterization of the spherical morphology of the nanoparticles. Furtherly, insulin was chosen as a model drug to study the application of the nanoparticles as a safe biodegradable nanocarrier system for drug-controlled release. An insulin entrapment efficiency of 75% was achieved in the chitosan-caseinate nanoparticles.

Formulation of Chitosan Polymeric Vesicles of Ciprofloxacin for Ocular Delivery: Box-Behnken Optimization, In Vitro Characterization, HET-CAM Irritation, and Antimicrobial Assessment

Ciprofloxacin is a commonly used antibiotic for treatment of bacterial conjunctivitis. The conventional eye drop dosage form is the widely used mode of treatment, but it has low corneal residence time. This drawback can be overcome by developing a bioadhesive noisome system (chitosan-coated) for enhanced corneal residence time. The niosomes were prepared by thin-film hydration technique and optimized by using Box-Behnken statistical design software. Cholesterol (A), Span 60 (B), and sonication time (C) were selected as independent variables, whereas vesicle size (Y₁ in nm), entrapment efficiency (Y₂ in %), and drug release (Y₃ in %) were chosen as dependent variables. The vesicle size, entrapment efficiency, and drug release of optimized CIP niosomes (CIP-NSMopt) were found to be 180.34 ± 5.13 nm, 78.32 ± 4.49%, and 82.87 ± 4.01% (in 12 h), respectively. Further CIP-NSMopt was coated with different chitosan concentrations (0.1 to 0.3%) to enhance mucoadhesion. Finally, optimized chitosan-coated niosomes (chitosomes; CIP-CHTopt) showed a vesicle size of 210.65 ± 2.76 nm, zeta potential of - 35.17 ± 2.25Mv, and PDI of 0.221. CIP-CHTopt exhibited sustained release profile (75.31% in 12 h) with the Korsmeyer-Peppas kinetic model (R² = 0.980). The permeation study showed 1.79-fold enhancements in corneal permeation compared with marketed CIP eye drop. The hen's egg chorioallantoic membrane (HET-CAM) study showed 0 scores (no irritation), and it was further confirmed by corneal hydration and histopathology study. The antimicrobial study exhibited a significant high zone (P < 0.05) of inhibition against tested organism. Our findings demonstrated that chitosan-coated niosomes are a promising drug carrier to enhance corneal contact time and treatment of bacterial conjunctivitis.

Bactericidal Activity of Usnic Acid-Chitosan Nanoparticles against Persister Cells of Biofilm-Forming Pathogenic Bacteria

The present study aimed to prepare usnic acid (UA)-loaded chitosan (CS) nanoparticles (UA-CS NPs) and evaluate its antibacterial activity against biofilm-forming pathogenic bacteria. UA-CS NPs were prepared through simple ionic gelification of UA with CS, and further characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and field-emission transmission electron microscopy. The UA-CS NPs presented a loading capacity (LC) of 5.2%, encapsulation efficiency (EE) of 24%, and a spherical shape and rough surface. The maximum release of UA was higher in pH 1.2 buffer solution as compared to that in pH 6.8 and 7.4 buffer solution. The average size and zeta potential of the UA-CS NPs was 311.5 ± 49.9 nm in diameter and +27.3 ± 0.8 mV, respectively. The newly prepared UA-CS NPs exhibited antibacterial activity against persister cells obtained from the stationary phase in batch culture, mature biofilms, and antibiotic-induced gram-positive and gram-negative pathogenic bacteria. Exposure of sub-inhibitory concentrations of UA-CS NPs to the bacterial cells resulted in a change in morphology. The present study suggests an alternative method for the application of UA into nanoparticles. Furthermore, the anti-persister activity of UA-CS NPs may be another possible strategy for the treatment of infections caused by biofilm-forming pathogenic bacteria.

Chitosan nanoparticles as a delivery platform for neurotoxin II from Androctonus australis hector scorpion venom: Assessment of toxicity and immunogenicity

In recent years, biodegradable polymers based nanoparticles received high interest for the development of vaccine delivery vehicles. In this study, chitosan nanoparticles encapsulating Aah II toxin (AahII-CNPs) isolated from Androctonus australis hector venom, were investigated as vaccine delivery system. Particles obtained by ionotropic gelation were characterized for their size, surface charge, morphology and toxin release profile from Aah II-CNPs. Toxin-nanoparticles interactions were assessed by Fourier Transform Infrared Spectrometry and X-Ray Diffraction. An immunization protocol was designed in mice to investigate anti-toxin immunity and the protective status induced by different Aah II immune formulations. Unloaded chitosan nanoparticles presenting a spherical shape and smooth surface, were characterized by a size of 185 nm, a dispersion index (PDI) of 0.257 and a zeta potential of +34.6 mV. Aah II toxin was successfully entrapped into chitosan nanoparticles as revealed by FTIR and XRD data. Entrapment efficiency (EE) and Loading capacity (LC) were respectively of 96.66 and 33.5%. Aah II-CNPs had a diameter of 208 nm, a PDI of 0.23 and a zeta potential of +30 mV. Encapsulation of Aah II reduced its toxicity and protected mice until 10 LD₅₀. Mice were immunized via a dual prime-boost scheme. Nanoentrapped Aah II immunogen elicited systemic innate and humoral immune responses as well as local spleen parenchyma hyperplasic alterations. Aah II-CNPs immunized mice withstood high lethal doses of native Aah II, one-month post-boost inoculation. This study provided encouraging and promising results for the development of preventive therapies against scorpion envenoming mainly for the populations at-risk.

Glycogen as a Building Block for Advanced Biological Materials

Biological nanoparticles found in living systems possess distinct molecular architectures and diverse functions. Glycogen is a unique biological polysaccharide nanoparticle fabricated by nature through a bottom-up approach. The biocatalytic synthesis of glycogen has evolved over time to form a nanometer-sized dendrimer-like structure (20-150 nm) with a highly branched surface and a dense core. This makes glycogen markedly different from other natural linear or branched polysaccharides and particularly attractive as a platform for biomedical applications. Glycogen is inherently biodegradable, nontoxic, and can be functionalized with diverse surface and internal motifs for enhanced biofunctional properties. Recently, there has been growing interest in glycogen as a natural alternative to synthetic polymers and nanoparticles in a range of applications. Herein, the recent literature on glycogen in the material-based sciences, including its use as a constituent in biodegradable hydrogels and fibers, drug delivery vectors, tumor targeting and penetrating nanoparticles, immunomodulators, vaccine adjuvants, and contrast agents, is reviewed. The various methods of chemical functionalization and physical assembly of glycogen nanoparticles into multicomponent nanodevices, which advance glycogen toward a functional therapeutic nanoparticle from nature and back again, are discussed in detail.

Biomolecular uptake effects on chitosan/tripolyphosphate micro- and nanoparticle stability

Colloidal chitosan/tripolyphosphate (TPP) particles have attracted significant attention as potential delivery vehicles for drugs, genes and vaccines. Yet, there have been several fundamental studies that showed these particles to disintegrate at physiological pH and ionic strength levels. To reconcile these findings with the published drug, gene and vaccine delivery research where chitosan/TPP particle disintegration was not reported, it has been postulated that the particles could be stabilized by their bioactive payloads. To test this hypothesis, here we examine whether the association of chitosan/TPP particles with model anionic proteins, α-lactalbumin (α-LA) and bovine serum albumin (BSA), and polynucleotides (DNA) enhances chitosan/TPP particle stability at physiological ionic strengths, using 150 mM NaCl (pH 5.5) and 1× PBS (pH 6.0) as the dissolution media. Light scattering and UV-vis spectroscopy revealed that anionic protein uptake had no impact on particle stability, likely due to the relatively weak protein/particle binding at near-physiological ionic strengths, which caused the protein to be rapidly released. This result occurred regardless of whether the protein was loaded during or after particle formation. Conversely, DNA uptake (at least at some compositions) increased the chitosan fractions persisting in a complexed/particulate form in model dissolution media, with the DNA remaining largely complexed to the chitosan at all investigated conditions. Collectively, these findings suggest that, while most bioactive payloads do not interact with chitosan strongly enough to stabilize chitosan/TPP particles, these chitosan particles can be stabilized to dissolution through the incorporation of polyanions.

Pectin-Tannic Acid Nano-Complexes Promote the Delivery and Bioactivity of Drugs in Pancreatic Cancer Cells

Pancreatic cancer (PanCa) is a lethal disease. Conventional chemotherapies for PanCa offer severe systemic toxicities. Thus, the development of a successful nanomedicine-based therapeutic regimen with augmented therapeutic efficacy is highly sought. Naturally occurring pectin and modified pectin-based drug delivery systems exhibit remarkable self-targeting ability via galactose residues to various cancer cells. Herein, we developed and used an innovative approach of highly stable nanocomplexes based on modified pectin and tannic acid (MPT-NCs). The nanocomplex formation was enabled by strong intermolecular interactions between pectin and tannic acid under very mild conditions. These nanocomplexes were characterized by particle size and morphology (DLS, TEM, and SEM), FT-IR spectroscopy, and zeta potential measurements. Additionally, MPT-NCs were capable of encapsulating anticancer drugs (5-fluorouracil, gemcitabine, and irinotecan) through tannic acid binding. The in vitro bioactivity of these drug MPT-NCs were evaluated in pancreatic cancer adenocarcinoma (PDAC) cell lines (HPAF-II and PANC-1). A dose-dependent internalization of nanocomplexes was evident from microscopy and flow cytometry analysis. Both proliferation and colony formation assays indicated the anticancer potential of pectin drug nanocomplexes against PDAC cells compared to that of free drug treatments. Together, the pectin-based nanocomplexes could be a reliable and efficient drug delivery strategy for cancer therapy.

Chitosan-based delivery systems for plants: A brief overview of recent advances and future directions

Chitosan has been termed as the most well-known among biopolymers, receiving widespread attention from researchers in various fields mainly, agriculture, food, and health. Chitosan is a deacetylated derivative of chitin, mainly isolated from waste shells of the phylum Arthropoda after their consumption as food. Chitosan molecules can be easily modified for adsorption and slow release of plant growth regulators, herbicides, pesticides, and fertilizers, etc. Chitosan as a carrier and control release matrix that offers many benefits including; protection of biomolecules from harsh environmental conditions such as pH, light, temperatures and prolonged release of active ingredients from its matrix consequently protecting the plant's cells from the hazardous effects of burst release. In the current review, tends to discuss the recent advances in the area of chitosan application as a control release system. Also, future recommendations will be made in light of current advancements and major gaps.

Characterizing the Physical Properties and Cell Compatibility of Phytoglycogen Extracted from Different Sweet Corn Varieties

Owing to its unique structure and properties, the glucose dendrimer phytoglycogen is gaining interest for medical and biotechnology applications. Although many maize variants are available from commercial and academic breeding programs, most applications rely on phytoglycogen extracted from the common maize variant, sugary1. Here we characterized the solubility, hydrodynamic diameter, water-binding properties, protein contaminant concentration, and cytotoxicity of phytoglycogens from different maize sources, A632su1, A619su1, Wesu7, and Ia453su1, harboring various sugary1 mutants. A619su1-SW phytoglycogen was cytotoxic while A632su1-SW phytoglycogen was not. A632su1-Pu phytoglycogen promoted cell growth, whereas extracts from A632su1-NE, A632su1-NC, and A632su1-CM were cytotoxic. Phytoglycogen extracted from Wesu7su1-NE using ethanol precipitation was cytotoxic. Acid-treatment improved Wesu7 phytoglycogen cytocompatibility. Protease-treated Wesu7 extracts promoted cell growth. Phytoglycogen extracted from Ia453su1 21 days after pollination (“Ia435su1 21DAP”) was cytotoxic, whereas phytoglycogen extracted at 40 days (“Ia435su1 40DAP”) was not. In general, size and solubility had no correlation with cytocompatibility, whereas protein contaminant concentration and water-binding properties did. A632su1-CM had the highest protein contamination among A632 mutants, consistent with its higher cytotoxicity. Likewise, Ia435su1 21DAP phytoglycogen had higher protein contamination than Ia435su1 40DAP. Conversely, protease-treated Wesu7 extracts had lower protein contamination than the other Wesu7 extracts. A632su1-NE, A632su1-NC, and A632su1-CM had similar water-binding properties which differed from those of A632su1-Pu and A632su1-SW. Likewise, water binding differed between Ia435su1 21DAP and Ia435su1 40DAP. Collectively, these data demonstrate that maize phytoglycogen extracts are not uniformly cytocompatible. Rather, maize variant, plant genotype, protein contaminants, and water-binding properties are determinants of phytoglycogen cytotoxicity.

Degradable Piezoelectric Biomaterials for Wearable and Implantable Bioelectronics

Current bioelectronics are facing a paradigm shift from old-fashioned unrecyclable materials to green and degradable functional materials with desired biocompatibility. As an essential electromechanical coupling component in many bioelectronics, new piezoelectric materials are being developed with biodegradability, as well as desired mechanical and electromechanical properties for the next generation implantable and wearable bioelectronics. In this review, we provide an overview of the major advancements in biodegradable piezoelectric materials. Different natural (such as peptide, amino acids, proteins, cellulose, chitin, silk, collagen, and M13 phage) and synthetic piezoelectric materials (such as polylactic acid) are discussed to reveal the underlying electromechanical coupling mechanism at the molecular level, together with typical approaches to the alignment of orientation and polarization to boost their electromechanical performance. Meanwhile, in vivo and in vitro degradation manners of those piezoelectric materials are summarized and compared. Representative developments of typical electronic prototypes leveraging these materials are also discussed. At last, challenges toward practical applications are pointed out together with potential research opportunities that might be critical in this new materials research area.

Oral nanoparticles based on gellan gum/pectin for colon-targeted delivery of resveratrol

Nanoparticles based on gellan gum/pectin blends were designed for colon-targeted release of resveratrol (RES). Their impact on drug release rates and permeability were evaluated using Caco-2 cell model and mucus secreting triple co-culture model. Polymeric nanoparticles (PNP) were successfully prepared by nebulization/ionotropic gelation, achieving high drug loading (>80%). PNP were spherical with a low positive charge density (+5mV) and exhibited diameters of around 330 nm. Developed PNP were able to promote effective modulation of drug release rates, so that only 3% of RES was released in acidic media over 2 h, and, in pH 6.8, the drug was released in a sustained manner, reaching 85% in 30 h. The permeability of RES-loaded PNP in the Caco-2 model was 0.15%, while in the triple co-culture model, in the presence of mucus, it reached 5.5%. The everted gut sac experiment corroborated the low permeability of RES-loaded PNP in the presence or absence of mucus and highlighted their high ability to interact with the intestinal tissue. Results indicate that the novel PNP developed in this work are safe and promising carriers for controlled delivery of RES at the colon.

Chitosan-modified hyaluronic acid-based nanosized drug carriers

Fabrication possibilities, detailed size and structural characterization of biodegradable chitosan (Chit) polysaccharide-modified hyaluronic acid (HyA)-based colloidal carriers are demonstrated. The negatively charged and highly hydrophilic HyA polymer chains have been ionically modified by positively charged pure Chit and crosslinked Chit macromolecules at various Chit/HyA weight ratios, which resulted in the formation of carrier nanoparticles (NPs) having three different nanostructures depending on the polymer concentrations. Electrostatically-compensated Chit/HyA polymer coils with loose colloidal structure, tripolyphosphate (TPP)-crosslinked Chit-TPP/HyA NPs having interpenetrating polymer network and well-defined Chit-TPP_core-HyA_shell NPs with diameters of 100-300 nm were also prepared and were loaded with tocopherol (TCP) and cholecalciferol (D3) having Vitamin E and D activity, respectively. By using rheological, particle charge titration and conductivity studies we first confirmed that the expected 1:1 Chit/HyA monomer molar ratio is strongly influenced by the pH of the polymer solutions as well as the deacetylation degree of Chit which are crucial factors for the solubility, purity and the quality of the commercially available biocompatible Chit in aqueous medium. Encapsulation studies revealed that D3 could be better incorporated in every system, especially in Chit-TPP/HyA NPs, while for TCP the simple Chit/HyA polymer coils were the most promising carriers.

Therapeutic efficacy of nanoparticles and routes of administration

In modern-day medicine, nanotechnology and nanoparticles are some of the indispensable tools in disease monitoring and therapy. The term “nanomaterials” describes materials with nanoscale dimensions (< 100 nm) and are broadly classified into natural and synthetic nanomaterials. However, “engineered” nanomaterials have received significant attention due to their versatility. Although enormous strides have been made in research and development in the field of nanotechnology, it is often confusing for beginners to make an informed choice regarding the nanocarrier system and its potential applications. Hence, in this review, we have endeavored to briefly explain the most commonly used nanomaterials, their core properties and how surface functionalization would facilitate competent delivery of drugs or therapeutic molecules. Similarly, the suitability of carbon-based nanomaterials like CNT and QD has been discussed for targeted drug delivery and siRNA therapy. One of the biggest challenges in the formulation of drug delivery systems is fulfilling targeted/specific drug delivery, controlling drug release and preventing opsonization. Thus, a different mechanism of drug targeting, the role of suitable drug-laden nanocarrier fabrication and methods to augment drug solubility and bioavailability are discussed. Additionally, different routes of nanocarrier administration are discussed to provide greater understanding of the biological and other barriers and their impact on drug transport. The overall aim of this article is to facilitate straightforward perception of nanocarrier design, routes of various nanoparticle administration and the challenges associated with each drug delivery method.

Modified chitosan-based nanoadjuvants enhance immunogenicity of protein antigens after mucosal vaccination

Nasal vaccination is considered to be an effective and convenient way of increasing immune responses both systemically and locally. Although various nanovaccine carriers have been introduced as potential immune adjuvants, further improvements are still needed before they can be taken to clinical usage. Chitosan-based nanovaccine carriers are one of the most widely studiedadjuvants, owing to the abilityof chitosan toopen tight junctions between nasal epithelial cells and enhance particle uptake as well as its inherent immune activating role. In present study, bovine serum albumin (BSA) loaded nanoparticles were prepared using novel aminated (aChi) and aminated plus thiolated chitosan (atChi) polymers, to further enhance mucoadhesiveness and adjuvanticity of the vaccine system by improving electrostatic interactions of polymers with negatively charged glycoproteins. Nanocarriers with optimum size and surface charge, high encapsulation efficiency of model antigen and good stability were developed. Negligible toxicity was observed in Calu-3 and A549 cell lines. In vivo studies, revealed high levels of systemic antibodies (IgG, IgG₁ and IgG_2a) throughout the study and presence of sIgA in vaginal washes showed that common mucosal system was successfully stimulated. Cytokine levels indicated a mixed Th1/Th2 immune response. A shift towards cellular immune responses was observed after nasal immunisation with antigen loaded nanoparticle formulations. These nanoparticles exhibit great potential for nasal application of vaccines.

Effect of lipopolysaccharide addition on the gene transfection of spermine-introduced pullulan-plasmid DNA complexes for human mesenchymal stem cells

The objective of this study is to investigate the effect of lipopolysaccharide (LPS) addition on the gene transfection of human mesenchymal stem cells (hMSC). hMSC were treated with the LPS at different concentrations and the complex of spermine-introduced pullulan and luciferase plasmid DNA for 3 h. The maximum level of gene expression was observed for hMSC treated with a certain concentration range of LPS. In addition, the cytotoxicity, cellular internalization of complexes, and cell cycle after LPS treatment were investigated. The cytotoxicity increased with an increase in the LPS concentration treated. On the other hand, the cellular internalization of complexes increased with the increased LPS concentration, although the internalization was sharply reduced at the high concentration. The LPS treatment increased the actin polymerization of cells to allow to spread more. The enhanced cells spreading would enhance the cellular internalization of complexes. In addition, the LPS treatment increased the rate of cell cycle. It is possible that the balance of cytotoxicity, cellular internalization, and cell cycle caused by the LPS addition results in the enhanced gene transfection at a certain LPS concentration. It is concluded that LPS treatment positively modified the cellular internalization and the cell cycle, resulting in the enhanced gene transfection.

Development of CS-TPP-dsRNA nanoparticles to enhance RNAi efficiency in the yellow fever mosquito, Aedes aegypti

Mosquito-borne diseases are a major threat to human health and are responsible for millions of deaths globally each year. Vector control is one of the most important approaches used in reducing the incidence of these diseases. However, increasing mosquito resistance to chemical insecticides presents challenges to this approach. Therefore, new strategies are necessary to develop the next generation vector control methods. Because of the target specificity of dsRNA, RNAi-based control measures are an attractive alternative to current insecticides used to control disease vectors. In this study, Chitosan (CS) was cross-linked to sodium tripolyphosphate (TPP) to produce nano-sized polyelectrolyte complexes with dsRNA. CS-TPP-dsRNA nanoparticles were prepared by ionic gelation method. The encapsulation efficiency, protection of dsRNA from nucleases, cellular uptake, in vivo biodistribution, larval mortality and gene knockdown efficiency of CS-TPP-dsRNA nanoparticles were determined. The results showed that at a 5:1 weight ratio of CS-TPP to dsRNA, nanoparticles of less than 200 nm mean diameter and a positive surface charge were formed. Confocal microscopy revealed the distribution of the fed CS-TPP-dsRNA nanoparticles in midgut, fat body and epidermis of yellow fever mosquito, Aedes aegypti larvae. Bioassays showed significant mortality of larvae fed on CS-TPP-dsRNA nanoparticles. These assays also showed knockdown of a target gene in CS-TPP-dsRNA nanoparticle fed larvae. These data suggest that CS-TPP nanoparticles may be used for delivery of dsRNA to mosquito larvae.

In vitro cytotoxicity and transfection efficiency of pDNA encoded p53 gene-loaded chitosan-sodium deoxycholate nanoparticles

Purpose: The objective of this work was to formulate a delivery system of pDNA encoded p53 gene-loaded chitosan-sodium deoxycholate (CS-DS) nanoparticles, and to evaluate their influence on in vitro cytotoxicity and transfection efficiency of p53 gene.

Methods: The prepared pDNA-loaded CS-DS nanoparticles were evaluated for morphology, particle size, zeta potential, entrapment efficiency %, in vitro release, in vitro cytotoxicity, and transfection efficiency.

Results: The mean particle size ranged from from 96.5 ± 11.31 to 405 ± 46.39 nm. All nanoparticles had good positive zeta potential values. Entrapment efficiency % ranged from 38.25 ± 3.25 to 94.89 ± 5.67. The agarose gel electrophoresis confirmed the strong binding between plasmid and CS. The in vitro pDNA release from nanoparticles exhibited an initial burst effect followed by a sustained drug release over a period of 6 days. In vitro cytotoxicity against human Caco-2 cells showed low cell cytotoxicity of plain CS-DS nanoparticles, while pDNA-loaded CS-DS nanoparticles showed a cytotoxic effect with increasing nanoparticles' concentration. Gene transfection, analyzed by PCR and ELISA, showed a direct correlation between gene expression and concentration of pDNA. The highest expression of the gene was achieved with pDNA concentration of 9 µg/mL with 5.7 times increase compared to naked pDNA of the same concentration.

Conclusion: The obtained results were very encouraging and offer an alternative approach to enhancing the transfection efficiency of genetic material-loaded chitosan-based delivery systems.

Novel approaches for the design, delivery and administration of vaccine technologies

It is easy to argue that vaccine development represents humankind's most important and successful endeavour, such is the impact that vaccination has had on human morbidity and mortality over the last 200 years. During this time the original method of Jenner and Pasteur, i.e. that of injecting live-attenuated or inactivated pathogens, has been developed and supplemented with a wide range of alternative approaches which are now in clinical use or under development. These next-generation technologies have been designed to produce a vaccine that has the effectiveness of the original live-attenuated and inactivated vaccines, but without the associated risks and limitations. Indeed, the method of development has undoubtedly moved away from Pasteur's three Is paradigm (isolate, inactivate, inject) towards an approach of rational design, made possible by improved knowledge of the pathogen-host interaction and the mechanisms of the immune system. These novel vaccines have explored methods for targeted delivery of antigenic material, as well as for the control of release profiles, so that dosing regimens can be matched to the time-lines of immune system stimulation and the realities of health-care delivery in dispersed populations. The methods by which vaccines are administered are also the subject of intense research in the hope that needle and syringe dosing, with all its associated issues regarding risk of injury, cross-infection and patient compliance, can be replaced. This review provides a detailed overview of new vaccine vectors as well as information pertaining to the novel delivery platforms under development.

Recent advances in the development of gene delivery systems

Background

Gene delivery systems are essentially necessary for the gene therapy of human genetic diseases. Gene therapy is the unique way that is able to use the adjustable gene to cure any disease. The gene therapy is one of promising therapies for a number of diseases such as inherited disorders, viral infection and cancers. The useful results of gene delivery systems depend open the adjustable targeting gene delivery systems. Some of successful gene delivery systems have recently reported for the practical application of gene therapy.

Main body

The recent developments of viral gene delivery systems and non-viral gene delivery systems for gene therapy have briefly reviewed. The viral gene delivery systems have discussed for the viral vectors based on DNA, RNA and oncolytic viral vectors. The non-viral gene delivery systems have also treated for the physicochemical approaches such as physical methods and chemical methods. Several kinds of successful gene delivery systems have briefly discussed on the bases of the gene delivery systems such as cationic polymers, poly(L-lysine), polysaccharides, and poly(ethylenimine)s.

Conclusion

The goal of the research for gene delivery system is to develop the clinically relevant vectors such as viral and non-viral vectors that use to combat elusive diseases such as AIDS, cancer, Alzheimer, etc. Next step research will focus on advancing DNA and RNA molecular technologies to become the standard treatment options in the clinical area of biomedical application.

Natural biodegradable polymers based nano-formulations for drug delivery: A review

Nanomedicines are now considered as the new-generation medication in the current era mainly because of their features related to nano size. The efficacy of many drugs in their micro/macro formulations is shown to have poor bioavailability and pharmacokinetics after oral administration. To overcome this predicament, use of natural/synthetic biodegradable polymeric nanoparticles (NPs) have gained prominence in the field of nanomedicine for targeted drug delivery to improve biocompatibility, bioavailability, safety, enhanced permeability, better retention time and lower toxicity. For drug delivery, it is essential to have biodegradable nanoparticle formulations for safe and efficient transport and release of drug at the intended site. Moreover, depending on the target organ, a suitable biodegradable polymer can be selected as the drug-carrier for target specific as well as for sustained drug delivery. The aim of this review is to present the current status and scope of natural biodegradable polymers as well as some emerging polymers with special characteristics as suitable carriers for drug delivery applications. The most widely preferred preparation methods are discussed along with their characterization using different analytical techniques. Further, the review highlights significant features of methods developed using natural polymers for drug entrapment and release studies.

Nutraceutical formulation, characterisation, and in-vitro evaluation of methylselenocysteine and selenocystine using food derived chitosan:zein nanoparticles

Selenoamino acids (SeAAs) have been shown to possess antioxidant and anticancer properties. However, their bioaccessibility is low and they may be toxic above the recommended nutritional intake level, thus improved targeted oral delivery methods are desirable. In this work, the SeAAs, Methylselenocysteine (MSC) and selenocystine (SeCys₂) were encapsulated into nanoparticles (NPs) using the mucoadhesive polymer chitosan (Cs), via ionotropic gelation with tripolyphosphate (TPP) and the NPs produced were then coated with zein (a maize derived prolamine rich protein). NPs with optimized physicochemical properties for oral delivery were obtained at a 6: 1 ratio of Cs:TPP, with a 1:0.75 mass ratio of Cs:zein coating (diameter ~260 nm, polydispersivity index ~0.2, zeta potential >30 mV). Scanning Electron Microscopy (SEM) analysis showed that spheroidal, well distributed particles were obtained. Encapsulation Efficiencies of 80.7% and 78.9% were achieved, respectively, for MSC and SeCys₂ loaded NPs. Cytotoxicity studies of MSC loaded NPs showed no decrease in cellular viability in either Caco-2 (intestine) or HepG2 (liver) cells after 4 and 72 h exposures. For SeCys₂ loaded NPs, although no cytotoxicity was observed in Caco-2 cells after 4 h, a significant reduction in cytotoxicity was observed, compared to pure SeCys₂, across all test concentrations in HepG2 after 72 h exposure. Accelerated thermal stability testing of both loaded NPs indicated good stability under normal storage conditions. Lastly, after 6 h exposure to simulated gastrointestinal tract environments, the sustained release profile of the formulation showed that 62 ± 8% and 69 ± 4% of MSC and SeCys₂, had been released from the NPs respectively.

Carboxymethyl cellulose coated magnetic nanoparticles transport across a human lung microvascular endothelial cell model of the blood-brain barrier

Sustained and safe delivery of therapeutic agents across the blood-brain barrier (BBB) is one of the major challenges for the treatment of neurological disorders as this barrier limits the ability of most drug molecules to reach the brain. Targeted delivery of the drugs used to treat these disorders could potentially offer a considerable reduction of the common side effects of their treatment. The preparation and characterization of carboxymethyl cellulose (CMC) coated magnetic nanoparticles (Fe₃O₄@CMC) is reported as an alternative that meets the need for novel therapies capable of crossing the BBB. In vitro assays were used to evaluate the ability of these polysaccharide coated biocompatible, water-soluble, magnetic nanoparticles to deliver drug therapy across a model of the BBB. As a drug model, dopamine hydrochloride loading and release profiles in physiological solution were determined using UV-Vis spectroscopy. Cell viability tests in Human Lung Microvascular Endothelial (HLMVE) cell cultures showed no significant cell death, morphological changes or alterations in mitochondrial function after 24 and 48 h of exposure to the nanoparticles. Evidence of nanoparticle interactions and nanoparticle uptake by the cell membrane was obtained by electron microscopy (SEM and TEM) analyses. Permeability through a BBB model (the transwell assay) was evaluated to assess the ability of Fe₃O₄@CMC nanoparticles to be transported across a densely packed HLMVE cell barrier. The results suggest that these nanoparticles can be useful drug transport and release systems for the design of novel pharmaceutical agents for brain therapy.

5β-Cholanic Acid/Glycol Chitosan Self-Assembled Nanoparticles (5β-CHA/GC-NPs) for Enhancing the Absorption of FDs and Insulin by Rat Intestinal Membranes

The absorption-enhancing effects of glycol chitosan modified by 5β-cholanic acid nanoparticles (5β-CHA/GC-NPs) on a drug with poor absorption in the intestine were studied by the method of in situ closed loop. We chose fluorescein isothiocyanate-labeled dextrans (FDs) and insulin as the model drugs. 5β-CHA/GC-NPs loaded to different drugs were prepared by the dialysis method, and the physicochemical characteristics and in vitro release profiles of nanoparticles were also estimated. The results showed that 5β-CHA/GC-NPs markedly increased the absorption of insulin and FDs in the jejunum, ileum, and colon. The ratios of absorption for all the drugs in the jejunum were higher than those in the ileum and colon. In addition, the enhancing effect of 5β-CHA/GC-NPs for the absorption of FDs from the jejunum was decreased with increasing molecular weights. In the toxicity test, 5β-CHA/GC-NPs did not significantly increase the release of protein and the activities of LDH, indicating that the nanoparticles did not cause any membrane damage to the intestine. These findings suggested that 5β-CHA/GC-NPs were safe and useful carriers for enhancing the absorption of the drug with poor absorption by intestinal membranes.

In vitro SPF and Photostability Assays of Emulsion Containing Nanoparticles with Vegetable Extracts Rich in Flavonoids

The aim of study was to determine the in vitro sun protection factor (SPF) and the photostability profile of a topical formulation composed of nanoparticles loaded with vegetable extracts and to assess its physicochemical properties. Chitosan/tripolyphosphate (TPP) nanoparticles loaded with flavonoids-enriched vegetable extracts (Ginkgo biloba L., Dimorphandra mollis Benth, Ruta graveolens, and Vitis vinifera L.) were produced and characterized for their morphology, mean particle size, zeta potential, and encapsulation efficiency. A final topical formulation was obtained by dispersing chitosan/TPP nanoparticles in an o/w emulsion. Results showed that nanoparticles dispersion exhibited yellowish color, spherical shape, and uniform appearance. Extract-loaded chitosan/TPP nanoparticles showed a mean particle size of 557.11 ± 3.1 nm, polydispersity index of 0.39 ± 0.27, zeta potential of + 11.54 ± 2.1 mV, and encapsulation efficiency of 75.89% of rutin. The recorded texture parameters confirm that the developed formulation is appropriate for skin application. The SPF obtained was 2.3 ± 0.4, with a critical wavelength of 387.0 nm and 0.69 UVA/UVB ratio. The developed formulation exhibited photostability, allowing the release of flavonoids from nanoparticles while retaining rutin into the skin in a higher extension.

Stearoyl-Chitosan Coated Nanoparticles Obtained by Microemulsion Cold Dilution Technique

Chitosan is an excipient which has been studied thoroughly in research works thanks to its positive characteristics such as muco-adhesiveness and ability to open epithelial-tight-junctions. In this article, lipophilic stearoyl chitosan (ST-CS) was synthetized in order to anchor this polymer to lipid nanoparticles and prepare ST-CS-coated nanoparticles (ST-CS-NP) using the microemulsion cold dilution technique. Curcumin (CURC) was used as model drug. CURC-ST-CS-NP were characterized by dimensional analysis, zeta potential, drug entrapment, drug release; tested in vitro on Human Umbilical Vein Endothelial Cell (HUVEC) cells to study its cytotoxicity and on human pancreatic cancer cells (PANC-1) to determine inhibition ability; tested in rats to determine CURC blood profiles and biodistribution. CURC-ST-CS-NP had mean diameters in the range 200–400 nm and CURC entrapment up to 73%. These systems did not show cytotoxicity on HUVEC cells at all tested dilutions and revealed to be more effective than free CURC solution on PANC-1 cells at 5 and 10 µM CURC. Blood profile studies evidenced as CURC entrapment in NP prolonged the permanence of drug in the systemic circulation compared to CURC solution due to a certain stealth property of NP, probably attributable to hydrophilic chitosan coating. Biodistribution studies showed a smaller CURC concentration in RES organs when CURC-ST-CS-NP were administered.

Ionically Crosslinked Chitosan Membranes Used as Drug Carriers for Cancer Therapy Application

The aim of this paper was to prepare, by the freeze-drying method, ionically crosslinked chitosan membranes with different contents of pentasodium tripolyphosphate (TPP) and loaded with 1,4-naphthoquinone (NQ14) drug, in order to evaluate how the physical crosslinking affects NQ14 release from chitosan membranes for cancer therapy application. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), swelling degree, and through in vitro drug release and cytotoxicity studies. According to the results, the molecular structure, porosity and hydrophilicity of the chitosan membranes were affected by TPP concentration and, consequently, the NQ14 drug release behavior from the membranes was also affected. The release of NQ14 from crosslinked chitosan membranes decreased when the cross-linker TPP quantity increased. Thus, depending on the TPP amount, the crosslinked chitosan membranes would be a potential delivery system to control the release of NQ14 for cancer therapy application. Lastly, the inhibitory potential of chitosan membranes ionically crosslinked with TPP and loaded with NQ14 against the B16F10 melanoma cell line was confirmed through in vitro cytotoxicity studies assessed via MTT assay. The anti-proliferative effect of prepared membranes was directly related to the amount of cross-linker and among all membranes prepared, such that one crosslinked with 0.3% of TPP may become a potential delivery system for releasing NQ14 drug for cancer therapy.

Hydrophobically modified chitosan nanoliposomes for intestinal drug delivery

Background

Encapsulation of hydrophilic drugs within liposomes can be challenging.

Methods

A novel chitosan derivative, O-palmitoyl chitosan (OPC) was synthesized from chitosan and palmitoyl chloride using methane-sulfonic acid as a solvent. The success of synthesis was confirmed by Fourier transform infra-red (FT-IR) spectroscopy and proton NMR spectroscopy (H-NMR). Liposomes encapsulating ferrous sulphate as a model hydrophilic drug for intestinal delivery were prepared with or without OPC inclusion (Lipo-Fe and OPC-Lipo-Fe).

Results

Entrapment of iron was significantly higher in OPC containing liposomes compared to controls. Quantitative iron absorption from the OPC liposomes was significantly higher (1.5-fold P<0.05) than free ferrous sulphate controls. Qualitative uptake analysis by confocal imaging using coumarin-6 dye loaded liposomes also indicated higher cellular uptake and internalization of the OPC-containing liposomes.

Conclusion

These findings suggest that addition of OPC during liposome preparation creates robust vesicles that have improved mucoadhesive and absorption enhancing properties. The chitosan derivative OPC therefore provides a novel alternative for formulation of delivery vehicles targeting intestinal absorption.

Chitosan-based nanoparticles as drug delivery systems: a review on two decades of research

Chitosan (CS) is one of the most functional natural biopolymer widely used in the pharmaceutical field due to its biocompatibility and biodegradability. These privileges lead to its application in the synthesis of nanoparticles for the drug during the last two decades. This article gives rise to a general review of the different chitosan nanoparticles (CSNPs) preparation techniques: Ionic gelation, emulsion cross-linking, spray-drying, emulsion-droplet coalescence method, nanoprecipitation, reverse micellar method, desolvation method, modified ionic gelation with radial polymerisation and emulsion solvent diffusion, from the point of view of the methodological and mechanistic aspects involved. The physicochemical behaviour of CSNPs including drug loading, drug release, particles size, zeta potential and stability are briefly discussed. This review also directs to bring an outline of the major applications of CSNPs in drug delivery according to drug and route of administration. Finally, derivatives of CSNPs and CS nano-complexes are also discussed.

Residence time and uptake of porous and cationic maltodextrin-based nanoparticles in the nasal mucosa: Comparison with anionic and cationic nanoparticles

Different types of biodegradable nanoparticles (NP) have been studied as nasal mucosa cell delivery systems. These nanoparticles need to strongly interact with mucosa cells to deliver their payload. However, only a few simultaneous comparisons have been made and it is therefore difficult to determine the best candidate. Here we compared 5 types of nanoparticles with different surface charge (anionic or cationic) and various inner compositions as potential vectors: cationic and anionic liposomes, cationic and anionic PLGA (Poly Lactic co-Glycolic Acid) NP and porous and cationic maltodextrin NP (cationic surface with an anionic lipid core: NPL). We first quantified their nasal residence time after nasal administration in mice using in vivo live imaging and NPL showed the longest residence time. In vitro endocytosis on mucosal cells (airway epithelial cells, macrophages and dendritic cells) using labeled nanoparticles were performed by flow cytometry and confocal microscopy. Among the 5 nanoparticles, NPL were taken up to the greatest extent by the 3 different cell lines and the endocytosis mechanisms were characterized. Taken together, we observed that the nanoparticles' cationic surface charge is insufficient to improve mucosal residence time and cellular uptake and that the NPL are the best candidates to interact with airway mucosal cells.

Hyaluronic Acid-Decorated Chitosan Nanoparticles for CD44-Targeted Delivery of Everolimus

Bronchiolitis obliterans syndrome (BOS), caused by lung allograft-derived mesenchymal cells' abnormal proliferation and extracellular matrix deposition, is the main cause of lung allograft rejection. In this study, a mild one-step ionotropic gelation method was set up to nanoencapsulate the everolimus, a key molecule in allograft organ rejection prevention, into hyaluronic acid-decorated chitosan-based nanoparticles. Rationale was the selective delivery of everolimus into lung allograft-derived mesenchymal cells; these cells are characterized by the CD44-overexpressing feature, and hyaluronic acid has proven to be a natural selective CD44-targeting moiety. The optimal process conditions were established by a design of experiment approach (full factorial design) aiming at the control of the nanoparticle size (≤200 nm), minimizing the size polydispersity (PDI 0.171 ± 0.04), and at the negative ζ potential maximization (-30.9 mV). The everolimus was successfully loaded into hyaluronic acid-decorated chitosan-based nanoparticles (95.94 ± 13.68 μg/100 mg nanoparticles) and in vitro released in 24 h. The hyaluronic acid decoration on the nanoparticles provided targetability to CD44-overexpressing mesenchymal cells isolated from bronchoalveolar lavage of BOS-affected patients. The mesenchymal cells' growth tests along with the nanoparticles uptake studies, at 37 °C and 4 °C, respectively, demonstrated a clear improvement of everolimus inhibitory activity when it is encapsulated in hyaluronic acid-decorated chitosan-based nanoparticles, ascribable to their active uptake mechanism.

Enhancing Passive Transport of Micro/Nano Particles into Cells by Oxidized Carbon Black

Uses of micro-/nano-sized particles to deliver biologically active entities into cells are common for medical therapeutics and prophylactics and also for cellular experiments. Enhancing cellular uptake and avoiding destruction by lysosomes are desirable for general particulate drug delivery systems. Here, we show that the relatively nontoxic, negatively charged oxidized carbon black particles (OCBs) can enhance cellular penetration of micro- and nano-particles. Experiments with retinal-grafted chitosan particles (PRPs) with hydrodynamic sizes of 1200 ± 51.5, 540 ± 29.0, and 430 ± 11.0 nm (three-sized model particles) indicate that only the sub-micron-sized particles can penetrate the first layer of multilayered liposomes. However, in the presence of OCBs, the micron-sized PRPs and the two submicron-sized PRPs can rapidly enter the interiors of all layers of the multilayered liposomes. Very low cellular uptakes of micro- and submicron-sized PRPs into keratinocytes cells are usually observed. However, in the presence of OCBs, faster and higher cellular uptakes of all of the three-sized PRPs are clearly noticed. Intracellular traffic monitoring of PRP uptake into HepG2 cells in the presence of OCBs revealed that the PRPs did not co-localize with endosomes, suggesting a nonendocytic uptake process. This demonstration of OCB's ability to enhance cellular uptake of micro- and submicron-particles should open up an easy strategy to effectively send various carriers into cells.

Schiff base-containing dextran nanogel as pH-sensitive drug delivery system of doxorubicin: Synthesis and characterization

Stimuli-responsive hydrogels have been widely researched as carrier systems, due to their excellent biocompatibility and responsiveness to external physiologic environment factors. In this study, dextran-based nanogel with covalently conjugated doxorubicin (DOX) was developed via Schiff base formation using the inverse microemulsion technique. Since the Schiff base linkages are acid-sensitive, drug release profile of the DOX-loaded nanogel would be pH-dependent. In vitro drug release studies confirmed that DOX was released much faster under acidic condition (pH 2.0, 5.0) than that at pH 7.4. Approximately 66, 28, and 9% of drug was released in 72 h at pH 2.0, 5.0, and 7.4, respectively. Cell uptake by the human breast cancer cell (MCF-7) demonstrated that the DOX-loaded dextran nanogel could be internalized through endocytosis and distributed in endocytic compartments inside tumor cells. These results indicated that the Schiff base-containing nanogel can serve as a pH-sensitive drug delivery system. And the presence of multiple aldehyde groups on the nanogel are available for further conjugations of targeting ligands or imaging probes.

Mesoscopic Modeling of the Encapsulation of Capsaicin by Lecithin/Chitosan Liposomal Nanoparticles

The transport of hydrophobic drugs in the human body exhibits complications due to the low solubility of these compounds. With the purpose of enhancing the bioavailability and biodistribution of such drugs, recent studies have reported the use of amphiphilic molecules, such as phospholipids, for the synthesis of nanoparticles or nanocapsules. Given that phospholipids can self-assemble in liposomes or micellar structures, they are ideal candidates to function as vehicles of hydrophobic molecules. In this work, we report mesoscopic simulations of nanoliposomes, constituted by lecithin and coated with a shell of chitosan. The stability of such structures and the efficiency of the encapsulation of capsaicin, as well as the internal and superficial distribution of capsaicin and chitosan inside the nanoliposome, were analyzed. The characterization of the system was carried out through density maps and the potentials of mean force for the lecithin-capsaicin, lecithin-chitosan, and capsaicin-chitosan interactions. The results of these simulations show that chitosan is deposited on the surface of the nanoliposome, as has been reported in some experimental works. It was also observed that a nanoliposome of approximately 18 nm in diameter is stable during the simulation. The deposition behavior was found to be influenced by a pattern of N-acetylation of chitosan.