Chitosan glutamate nanoparticles for protein delivery: Development and effect on prolidase stability

The Chemical Modification to Improve Solubility of Chitosan and Its Derivatives Application, Preparation Method, Toxicity as a Nanoparticles

Chitosan is a functional polymer in the pharmaceutical field, including for nanoparticle drug delivery systems. Chitosan-based nanoparticles are a promising carrier for a wide range of therapeutic agents and can be administered in various routes. Solubility is the main problem for its production and utilization in large-scale industries. Chitosan modifications have been employed to enhance its solubility, including chemical modification. Many reviews have reported the chemical modification but have not focused on the specific characteristics obtained. This review focused on the modification to improve chitosan solubility. Additionally, this review also focused on the application of chitosan derivatives in nanoparticle drug delivery systems since very few similar reviews have been reported. The specific method for chitosan derivative-based nanoparticles was also reported and the latest report of chitosan, chitosan derivative, and chitosan toxicity were also described.

Impacts of chitosan and its nanoformulations on the metabolic syndromes: a review

A significant public health issue worldwide is metabolic syndrome, a cluster of metabolic illnesses that comprises insulin resistance, obesity, dyslipidemia, hyperglycemia, and hypertension. The creation of natural treatments and preventions for metabolic syndrome is crucial. Chitosan, along with its nanoformulations, is an oligomer of chitin, the second-most prevalent polymer in nature, which is created via deacetylation. Due to its plentiful biological actions in recent years, chitosan and its nanoformulations have drawn much interest. Recently, the chitosan nanoparticle-based delivery of CRISPR-Cas9 has been applied in treating metabolic syndromes. The benefits of chitosan and its nanoformulations on insulin resistance, obesity, diabetes mellitus, dyslipidemia, hyperglycemia, and hypertension will be outlined in the present review, highlighting potential mechanisms for the avoidance and medication of the metabolic syndromes by chitosan and its nanoformulations.

Sustainable functionalized chitosan based nano-composites for wound dressings applications: A review

Functionalized chitosan nanocomposites have been studied for wound dressing applications due to their excellent antibacterial and anti-fungal properties. Polysaccharides show excellent antibacterial and drug-release properties and can be utilized for wound healing. In this article, we comprise distinct approaches for chitosan functionalization, such as photosensitizers, dendrimers, graft copolymerization, quaternization, acylation, carboxyalkylation, phosphorylation, sulfation, and thiolation. The current review article has also discussed brief insights on chitosan nanoparticle processing for biomedical applications, including wound dressings. The chitosan nanoparticle preparation technologies have been discussed, focusing on wound dressings owing to their targeted and controlled drug release behavior. The future directions of chitosan research include; a) finding an effective solution for chronic wounds, which are unable to heal completely; b) providing effective wound healing solutions for diabetic wounds and venous leg ulcers; c) to better understanding the wound healing mechanism with such materials which can help provide the optimum solution for wound dressing; d) to provide an improved treatment option for wound healing.

Chitosan Nanoparticles: A Versatile Platform for Biomedical Applications

Chitosan is a biodegradable and biocompatible natural polymer that has been extensively explored in recent decades. The Food and Drug Administration has approved chitosan for wound treatment and nutritional use. Furthermore, chitosan has paved the way for advancements in different biomedical applications including as a nanocarrier and tissue-engineering scaffold. Its antibacterial, antioxidant, and haemostatic properties make it an excellent option for wound dressings. Because of its hydrophilic nature, chitosan is an ideal starting material for biocompatible and biodegradable hydrogels. To suit specific application demands, chitosan can be combined with fillers, such as hydroxyapatite, to modify the mechanical characteristics of pH-sensitive hydrogels. Furthermore, the cationic characteristics of chitosan have made it a popular choice for gene delivery and cancer therapy. Thus, the use of chitosan nanoparticles in developing novel drug delivery systems has received special attention. This review aims to provide an overview of chitosan-based nanoparticles, focusing on their versatile properties and different applications in biomedical sciences and engineering.

Synthesis and ex vivo evaluation of PLGA chitosan surface modulated double walled transdermal Pluronic nanogel for the controlled delivery of Temozolomide

A surface modulated biodegradable transdermal strategy has been exploited for improving the biopharmaceutical properties of Temozolomide augmented in Poly Lactic-co-glycolic acid (PLGA) chitosan double walled nanogel (PCNGL). The PCNGL was synthesized by dual approach methodology showing consistent nanosize particle range of 210 nm and PDI 0.325 ± 0.43 with cationic zeta potential values +29.34 ± 0.79 mV. The PCNGL showed qualitative endothermic & exothermic temperature dependent degradation peaks by thermogravimetry analysis. Blood hemolysis and coagulation assay showed 3.37 ± 0.19 as hemolytic ratio, validating biologically safe margin for transdermal delivery. The in vitro drug release showed 85% transdermal release at slightly acidic pH mimicking skin microenvironment. The ex vivo studies displayed noteworthy penetration potential validated by concentration depth assay and confocal laser scanning microscopy, exhibiting 80% Temozolomide uptake in porcine epidermal tissue. The current research demonstrated the biodegradable controlled delivery of chemotherapeutic Temozolomide leading to biologically safe transdermal therapy.

In Silico and In Vitro Tailoring of a Chitosan Nanoformulation of a Human Metabolic Enzyme

Enzyme nanoencapsulation holds an enormous potential to develop new therapeutic approaches to a large set of human pathologies including cancer, infectious diseases and inherited metabolic disorders. However, enzyme formulation has been limited by the need to maintain the catalytic function, which is governed by protein conformation. Herein we report the rational design of a delivery system based on chitosan for effective encapsulation of a functionally and structurally complex human metabolic enzyme through ionic gelation with tripolyphosphate. The rationale was to use a mild methodology to entrap the multimeric multidomain 200 kDa human phenylalanine hydroxylase (hPAH) in a polyol-like matrix that would allow an efficient maintenance of protein structure and function, avoiding formulation stress conditions. Through an in silico and in vitro based development, the particulate system was optimized with modulation of nanomaterials protonation status, polymer, counterion and protein ratios, taking into account particle size, polydispersity index, surface charge, particle yield production, protein free energy of folding, electrostatic surface potential, charge, encapsulation efficiency, loading capacity and transmission electron microscopy morphology. Evaluation of the thermal stability, substrate binding profile, relative enzymatic activity, and substrate activation ratio of the encapsulated hPAH suggests that the formulation procedure does not affect protein stability, allowing an effective maintenance of hPAH biological function. Hence, this study provides an important framework for an enzyme formulation process.

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.

Impact of nanoencapsulated natural bioactive phenolic metabolites on chitosan nanoparticles as aflatoxins inhibitor

Aflatoxins are part of fungal secondary metabolites which become serious health, environmental, and economic problems and can cause corruption of many crops and agricultural grains that used as food and feed for human and animal. Aflatoxins mainly produce by Aspergillus spp. especially Aspergillus flavus and Aspergillus parasiticus. The present work aimed to study the effect of nanoencapsulation of chitosan (CS) nanoparticles with two phenolic compounds 1-(2-ethyl,6-heptyl)phenol (EHP) extracted from Cuminum cyminum and 5-ethyl-2-(methoxymethyl)phenol (EMMP) extracted from black pepper on growth and aflatoxins production of A. flavus and A. parasiticus. A. flavus growth was completely inhibited by 0.6 mg/ml of EHP and EMMP as well as A. parasiticus which showed the same minimal inhibition concentration with the first compound and 0.8 mg/ml with the second one. CS nanoparticles inhibited the growth of the tested organisms more than CS especially with A. parasiticus and this potency became much better when nanoencapsulated with the two extracted phenolic compounds. In inhibition of aflatoxins production, EHP reduced the production of aflatoxin B1 and B2 of A. flavus by 68.6% and 69.7%, respectively. In the same manner EMMP reduce the production of the two toxins by 87.3% and 82.6%, respectively. The reduction effect of CS nanoparticles is much more than that of CS as it record in most cases about twofold increase. Nanoencapsulation of CS nanoparticles by the extracted phenolic compounds is much more effective with complete inhibition of aflatoxin B1 of both fungi and aflatoxin G1 of A. parasiticus.

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.

Preparation of chitosan/tripolyphosphate nanoparticles with highly tunable size and low polydispersity

Nanoparticles prepared through the ionotropic gelation of chitosan with tripolyphosphate (TPP) have been extensively studied as vehicles for drug and gene delivery. Though a number of these works have focused on preparing particles with narrow size distributions, the monodisperse particles produced by these methods have been limited to narrow size ranges (where the average particle size was not varied by more than twofold). Here we show how, by tuning the NaCl concentration in the parent chitosan and TPP solutions, low-polydispersity particles with z-average diameters ranging between roughly 100 and 900nm can be prepared. Further, we explore how the size of these particles depends on the method by which the TPP is mixed into the chitosan solution, specifically comparing: (1) single-shot mixing; (2) dropwise addition; and (3) a dilution technique, where chitosan and TPP are codissolved at a high (gelation-inhibiting) ionic strength and then diluted to lower ionic strengths to trigger gelation. Though the particle size increases sigmoidally with the NaCl concentration for all three mixing methods, the dilution method delivers the most uniform/gradual size increase - i.e., it provides the most precise control. Also investigated are the effects of mixture composition and mixing procedure on the particle yield. These reveal the particle yield to increase with the chitosan/TPP concentration, decrease with the NaCl concentration, and vary only weakly with the mixing protocol; thus, at elevated NaCl concentrations, it may be beneficial to increase chitosan and TPP concentrations to ensure high particle yields. Finally, possible pitfalls of the salt-assisted size control strategy (and their solutions) are discussed. Taken together, these findings provide a simple and reliable method for extensively tuning chitosan/TPP particle size while maintaining narrow size distributions.

Internalized chitosan nanoparticles persist for long time in cultured cells

Chitosan-based nanoparticles (chiNPs) are considered to be potentially good carriers for the sustained intracellular delivery of specific molecules. However, scarce attention has been paid to the long-lasting permanence of these NPs in the intracellular milieu, as well as to their intracellular fate (i.e., distribution, interaction with cell organelles, and degradation) in the long term. In the present study, the presence and subcellular location of FITC-labelled chiNPs were monitored in HeLa cells up to 14 days post-administration using multicolorfluorescence confocal microscopy and diaminobenzidine photo-oxidation at transmission electron microscopy. The main result of the present study is the demonstration that internalized chiNPs persist inside the cell up to two weeks, occurring in both the cytoplasm and nucleus; accordingly, chiNPs are able to pass from mother to daughter cells through several mitotic cycles. The cells did not show increased mortality or structural damage up to 14 days after chiNP exposure.

Factors affecting the stability of chitosan/tripolyphosphate micro- and nanogels: resolving the opposing findings

The stability of submicron chitosan/tripolyphosphate particles depends on the chitosan type, pH, ionic strength and particle concentration.

Formation and dissolution of chitosan/pyrophosphate nanoparticles: is the ionic crosslinking of chitosan reversible?

Ionically crosslinked chitosan particles with submicron dimensions attract widespread interest as materials for controlled release. To this end, we have examined the formation and dissolution of nanoparticles prepared by crosslinking chitosan with pyrophosphate (PPi). The formation of these particles required a critical PPi concentration (which increased with the chitosan concentration), and their z-average hydrodynamic diameters could be predictably tuned from roughly 60 to 220 nm by varying the concentration of the parent chitosan solutions. Unlike the nanoparticles crosslinked with the commonly used tripolyphosphate (TPP), which coagulated and precipitated when TPP was in excess, the chitosan/PPi nanoparticles remained colloidally stable even at high PPi concentrations. Moreover, the analysis of their dissolution revealed hysteresis in the particle formation/dissolution cycle, where portions of the crosslinked chitosan/PPi complexes remained stably intact at PPi concentrations below those required for their formation. This irreversible behavior was surmised to reflect the cooperativity of chitosan/PPi binding and was qualitatively modeled using the Bragg-Williams theory.

Biomedical applications of immobilized enzymes: an update

Immobilized enzymes have been widely studied during the last few decades. Biocatalyst systems may work as biosensors or may be used for the treatment of different diseases. This chapter presents different attempts to immobilize enzymes in the biomedical field, particularly the use of prolidase and superoxide dismutase as two examples of this approach. Although this chapter focuses on liposomes and nanoparticles for the entrapment of these enzymes, the methods detailed here could be adapted for the immobilization of other enzymes with therapeutic purposes.

Prolidase function in proline metabolism and its medical and biotechnological applications

Prolidase is a multifunctional enzyme that possesses the unique ability to degrade imidodipeptides in which a proline or hydroxyproline residue is located at the C-terminal end. Prolidases have been isolated from archaea and bacteria, where they are thought to participate in proline recycling. In mammalian species, prolidases are found in the cytoplasm and function primarily to liberate proline in the final stage of protein catabolism, particularly during the biosynthesis and degradation of collagen. Collagen comprises nearly one-third of the total protein in the body, and it is essential in maintaining tissue structure and integrity. Prolidase deficiency (PD), a rare autosomal recessive disorder in which mutations in the PEPD gene affect prolidase functionality, tends to have serious and sometimes life-threatening clinical symptoms. Recombinant prolidases have many applications and have been investigated not only as a possible treatment for PD, but also as a part of anti-cancer strategies, a component of biodecontamination cocktails and in the dairy industry. This review will serve to discuss the many in vivo functions of procaryotic and eucaryotic prolidases, as well as the most recent advances in therapeutic and biotechnological application of prolidases.

Diaminobenzidine photoconversion is a suitable tool for tracking the intracellular location of fluorescently labelled nanoparticles at transmission electron microscopy

Chitosan-based nanoparticles (NPs) deserve particular attention as suitable drug carriers in the field of pharmaceutics, since they are able to protect the encapsulated drugs and/or improve their efficacy by making them able to cross biological barriers (such as the blood-brain barrier) and reach their intracellular target sites. Understanding the intracellular location of NPs is crucial for designing drug delivery strategies. In this study, fluorescently-labelled chitosan NPs were administered in vitro to a neuronal cell line, and diaminobenzidine (DAB) photoconversion was applied to correlate fluorescence and transmission electron microscopy to precisely describe the NPs intracellular fate. This technique allowed to demonstrate that chitosan NPs easily enter neuronal cells, predominantly by endocytosis; they were found both inside membrane-bounded vesicles and free in the cytosol, and were observed to accumulate around the cell nucleus.

Induction of an in vitro reversible hypometabolism through chitosan-based nanoparticles

OBJECTIVE

Chitosan-based nanoparticles (NPs) were prepared to promote intracellular sustained delivery of the synthetic delta opioid D-Ala(2)-D-Leu(5)-enkephalin (DADLE), prolonging peptide activity and inducing a safe and reversible hypometabolic state.

MATERIALS AND METHODS

NPs were prepared by combining ionotropic gelation and ultrasonication treatment. NP uptake studies and the effects of encapsulated DADLE on HeLa cells proliferation were tested by transmission electron microscopy (TEM) analysis, by immuno-fluorescence and immuno-cytochemistry.

RESULTS

DADLE-loaded NPs are produced with suitable characteristics, a satisfactory process yield (55.4% ± 2.4%) and encapsulation efficiency (64.6% ± 2.1%). NPs are effective in inducing a hypometabolic stasis at a 10(-4) M DADLE concentration. Moreover, as seen from the immunofluorescence study, the effect persists through the recovery period (72 h). Indeed, NPs labelled by anti-enkephalin antibody inside cell nucleus reassert that the in vivo release of the peptide can be prolonged with respect to the case of free peptide supply.

CONCLUSION

The nanoparticulate drug delivery system described seems to be effective in inducing and prolonging a sort of hibernation-like state in the cells.

Biomedical Applications of Biodegradable Polymers

Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. In order to fit functional demand, materials with desired physical, chemical, biological, biomechanical and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.

PEG-PLA microparticles for encapsulation and delivery of Tat-EGFP to retinal cells

The efficient and controlled delivery of genes and proteins to retinal cells remains a challenge. In this study, we evaluated polyethylene glycol-polylactic acid (PEG-PLA) microparticles for encapsulation and delivery of a Transactivator of transcription-enhanced green fluorescent protein fusion (Tat-EGFP) to retinal cells. Our main objective was to develop a microparticle system that delivers Tat-EGFP with an initial rapid release (within 24 h) followed by a sustained release. We prepared four different formulations of Tat-EGFP encapsulated PEG-PLA particles to investigate the effects of protein and polymer concentrations on particle morphology and protein release, using scanning electron microscopy (SEM) and fluorometry techniques. The optimum formulation was selected based on higher protein release, and smaller particle size. The optimum formulation was then tested in vitro for cell biocompatibility and protein internalization, and in vivo for cellular toxicity following sub-retinal injections into rat eyes. The results suggest that PEG-PLA microparticles can deliver proteins in cell culture allowing protein internalization in as little as 1 h. In vivo, protein was shown to localize within the photoreceptor layer of the retina, and persist for at least 9 weeks with no observed toxicity.

Chitosan glutamate hydrogels with local anesthetic activity for buccal application

Hydrogels for the buccal application of the anesthetic drug lidocaine hydrochloride (LDC) were prepared using chitosan glutamate (CHG), a soluble salt of chitosan, or a binary mixture of CHG and glycerin, at different weight ratios. The in vitro drug release was studied at the pH value of saliva to assess the effect of the different formulations on drug delivery. The anesthetic activity of mucoadhesive LDC-CHG hydrogels was assessed in vivo after application on the buccal mucosa, compared to commercial semisolid formulations containing the same drug. LDC-loaded hydrogels can be proposed for the symptom relief of aphthosis or other painful mouth diseases.

Biotechnological applications of recombinant microbial prolidases

Prolidase is a metallopeptidase that is ubiquitous in nature and has been isolated from mammals, bacteria and archaea. Prolidase specifically hydrolyzes dipeptides with a prolyl residue in the carboxy terminus (NH(2)-X-/-Pro-COOH). Currently, the only solved structure of prolidase is from the hyperthermophilic archaeon Pyrococcus furiosus. This enzyme is of particular interest because it can be used in many biotechnological applications. Prolidase is able to degrade toxic organophosphorus (OP) compounds, namely, by cleaving the P-F and P-O bonds in the nerve agents, sarin and soman. Applications using prolidase to detoxify OP nerve agents include its incorporation into fire-fighting foams and as biosensors for OP compound detection. Prolidases are also employed in the cheese-ripening process to improve cheese taste and texture. In humans, prolidase deficiency (PD) is a rare autosomal recessive disorder that affects the connective tissue. Symptoms of PD include skin lesions, mental retardation and recurrent respiratory infections. Enzyme replacement therapies are currently being studied in an effort to optimize enzyme delivery and stability for this application. Previously, prolidase has been linked to collagen metabolism and more recently is being associated with melanoma. Increased prolidase activity in melanoma cell lines has lead investigators to create cancer prodrugs targeting this enzyme. Thus, there are many biotechnological applications using recombinant and native forms of prolidase and this review will describe the biochemical and structural properties of prolidases as well as discuss their most current applications.