Hyaluronic acid/Chitosan nanoparticles as delivery vehicles for VEGF and PDGF-BB

Antibacterial properties of photo-crosslinked chitosan/methacrylated hyaluronic acid nanoparticles loaded with bacitracin

The current treatments for wounds often fail to induce adequate healing, leaving wounds vulnerable to persistent infections and development of drug-resistant microbial biofilms. New natural-derived nanoparticles were studied to impair bacteria colonization and hinder the formation of biofilms in wounds. The nanoparticles were fabricated through polyelectrolyte complexation of chitosan (CS, polycation) and hyaluronic acid (HA, polyanion). UV-induced photo-crosslinking was used to enhance the stability of the nanoparticles. To achieve this, HA was methacrylated (HAMA, degree of modification of 20 %). Photo-crosslinked nanoparticles obtained from HAMA and CS had a diameter of 478 nm and a more homogeneous size distribution than nanoparticles assembled solely through complexation (742 nm). The nanoparticles were loaded with the antimicrobial agent bacitracin (BC), resulting in nanoparticles with a diameter of 332 nm. The encapsulation of BC was highly efficient (97 %). The BC-loaded nanoparticles showed significant antibacterial activity against gram-positive bacteria Staphylococcus aureus, Methicillin-resistant S. aureus and S. epidermidis. Photo-crosslinked HAMA/CS nanoparticles loaded with BC demonstrated inhibition of biofilm formation and a positive effect on the proliferation of mammalian cells (L929). These crosslinked nanoparticles have potential for the long-term treatment of wounds and controlled antibiotic delivery at the location of a lesion.

Nanogel delivery systems for cationic peptides: More than a 'One Size Fits All' solution

Self-assembled hyaluronic acid-based nanogels are versatile drug carriers due to their biodegradable nature and gentle preparation conditions, making them particularly interesting for delivery of peptide therapeutics. This study aims to elucidate the relation between peptide structure and encapsulation in a nanogel. Key peptide properties that affect encapsulation in octenyl succinic anhydride-modified hyaluronic acid nanogels were identified as we explored the effect on nanogel characteristics using 12 peptides with varying charge and hydrophobicity. The size and surface properties of the microfluidics-assembled peptide-loaded nanogels were evaluated using dynamic light scattering, laser Doppler electrophoresis, and small angle neutron scattering. Additionally, the change in peptide secondary structure upon encapsulation in nanogels, their release from the nanogels, and the in vitro antimicrobial activity were assessed. In conclusion, the more hydrophobic peptides showed stronger binding to the nanogel carrier and localized internally rather than on the surface of the nanogel, resulting in more spherical nanogels with smoother surfaces and slower release profiles. In contrast, cationic and hydrophilic peptides localized at the nanogel surface resulting in fluffier nanogel structures and quick and more complete release in biorelevant medium. These findings emphasize that the advantages of nanogel delivery systems for different applications depend on the therapeutic peptide properties.

Vascular endothelial growth factor (VEGF) delivery approaches in regenerative medicine

The utilization of growth factors in the process of tissue regeneration has garnered significant interest and has been the subject of extensive research. However, despite the fervent efforts invested in recent clinical trials, a considerable number of these studies have produced outcomes that are deemed unsatisfactory. It is noteworthy that the trials that have yielded the most satisfactory outcomes have exhibited a shared characteristic, namely, the existence of a mechanism for the regulated administration of growth factors. Despite the extensive exploration of drug delivery vehicles and their efficacy in delivering certain growth factors, the development of a reliable predictive approach for the delivery of delicate growth factors like Vascular Endothelial Growth Factor (VEGF) remains elusive. VEGF plays a crucial role in promoting angiogenesis; however, the administration of VEGF demands a meticulous approach as it necessitates precise localization and transportation to a specific target tissue. This process requires prolonged and sustained exposure to a low concentration of VEGF. Inaccurate administration of drugs, either through off-target effects or inadequate delivery, may heighten the risk of adverse reactions and potentially result in tumorigenesis. At present, there is a scarcity of technologies available for the accurate encapsulation of VEGF and its subsequent sustained and controlled release. The objective of this review is to present and assess diverse categories of VEGF administration mechanisms. This paper examines various systems, including polymeric, liposomal, hydrogel, inorganic, polyplexes, and microfluidic, and evaluates the appropriate dosage of VEGF for multiple applications.

Extracellular matrix component-derived nanoparticles for drug delivery and tissue engineering

The extracellular matrix (ECM) consists of a complex combination of proteins, proteoglycans, and other biomolecules. ECM-based materials have been demonstrated to have high biocompatibility and bioactivity, which may be harnessed for drug delivery and tissue engineering applications. Herein, nanoparticles incorporating ECM-based materials and their applications in drug delivery and tissue engineering are reviewed. Proteins such as gelatin, collagen, and fibrin as well as glycosaminoglycans including hyaluronic acid, chondroitin sulfate, and heparin have been employed for cancer therapeutic delivery, gene delivery, and wound healing and regenerative medicine. Strategies for modifying and functionalizing these materials with synthetic and natural polymers or to enable stimuli-responsive degradation and drug release have increased the efficacy of these materials and nano-systems. The incorporation and modification of ECM-based materials may be used to drive drug targeting and increase tissue-specific cell differentiation more effectively.

Mannose-modified hyaluronic acid nanocapsules for the targeting of tumor-associated macrophages

Tumor-associated macrophages (TAMs), a class of immune cells that play a key role in tumor immunosuppression, are recognized as important targets to improve cancer prognosis and treatment. Consequently, the engineering of drug delivery nanocarriers that can reach TAMs has acquired special relevance. This work describes the development and biological evaluation of a panel of hyaluronic acid (HA) nanocapsules (NCs), with different compositions and prepared by different techniques, designed to target macrophages. The results showed that plain HA NCs did not significantly influence the polarization of M0 and M2-like macrophages towards an M1-like pro-inflammatory phenotype; however, the chemical functionalization of HA with mannose (HA-Man) led to a significant increase of NCs uptake by M2 macrophages in vitro and to an improved biodistribution in a MN/MNCA1 fibrosarcoma mouse model with high infiltration of TAMs. These functionalized HA-Man NCs showed a higher accumulation in the tumor compared to non-modified HA NCs. Finally, the pre-administration of the liposomal liver occupying agent Nanoprimer™ further increased the accumulation of the HA-Man NCs in the tumor. This work highlights the promise shown by the HA-Man NCs to target TAMs and thus provides new options for the development of nanomedicine and immunotherapy-based cancer treatments.

Skin targeting by chitosan/hyaluronate hybrid nanoparticles for the management of irritant contact dermatitis: In vivo therapeutic efficiency in mouse-ear dermatitis model

Irritant contact dermatitis (ICD) is an inflammatory skin condition characterized by severe eczematous lesions. Nanoparticulate drug delivery is the most predominant way to improve dermal penetration and have gained remarkable recognition for targeted delivery of therapeutic payload and reduced off-target effects. Therefore, the current work aimed to fabricate polyelectrolyte complex nanoparticles (PENPs) containing two natural biodegradable polymers namely; chitosan (CS) and hyaluronic acid (HA) to deliver the non steroidal anti-inflammatory drug etoricoxib (ETX) to the deeper skin layers to alleviate any systemic toxicity and improve its therapeutic efficacy against ICD. ETX loaded-PENPs were prepared and optimized utilizing three independent variables; CS: HA mass ratio, chitosan solution pH and molecular weight of chitosan. Following the various physicochemical optimizations, the optimum ETX-loaded PENPs formulation (N1 0.15 %) exhibited spherical nature with an average diameter of 267.9 ± 9.4 nm, Polydispersity index of 0.366 ± 0.02, and positive zeta potential (+32.9 ± 0.47 mV). The drug was successfully entrapped and the entrapment efficiency reached 95 ± 0.2 %. N1 0.15 % formula showed efficient dermal targeting by significantly enhanced percentage of ETX permeated and retained in the various skin layers in comparison to ETX conventional gel during the ex-vivo skin permeation experiments. Furthermore, N1 0.15 % exhibited superior anti-inflammatory properties in vivo compared to ETX conventional gel in dithranol induced mice ear dermatitis. Conclusively, ETX-loaded PENPs could be a promising therapeutic approach for effecient management of ICD.

Biocompatible Macroion/Growth Factor Assemblies for Medical Applications

Growth factors are a class of proteins that play a role in the proliferation (the increase in the number of cells resulting from cell division) and differentiation (when a cell undergoes changes in gene expression becoming a more specific type of cell) of cells. They can have both positive (accelerating the normal healing process) and negative effects (causing cancer) on disease progression and have potential applications in gene therapy and wound healing. However, their short half-life, low stability, and susceptibility to degradation by enzymes at body temperature make them easily degradable in vivo. To improve their effectiveness and stability, growth factors require carriers for delivery that protect them from heat, pH changes, and proteolysis. These carriers should also be able to deliver the growth factors to their intended destination. This review focuses on the current scientific literature concerning the physicochemical properties (such as biocompatibility, high affinity for binding growth factors, improved bioactivity and stability of the growth factors, protection from heat, pH changes or appropriate electric charge for growth factor attachment via electrostatic interactions) of macroions, growth factors, and macroion-growth factor assemblies, as well as their potential uses in medicine (e.g., diabetic wound healing, tissue regeneration, and cancer therapy). Specific attention is given to three types of growth factors: vascular endothelial growth factors, human fibroblast growth factors, and neurotrophins, as well as selected biocompatible synthetic macroions (obtained through standard polymerization techniques) and polysaccharides (natural macroions composed of repeating monomeric units of monosaccharides). Understanding the mechanisms by which growth factors bind to potential carriers could lead to more effective delivery methods for these proteins, which are of significant interest in the diagnosis and treatment of neurodegenerative and civilization diseases, as well as in the healing of chronic wounds.

Scaffold Using Chitosan, Agarose, Cellulose, Dextran and Protein for Tissue Engineering-A Review

Biological macromolecules like polysaccharides/proteins/glycoproteins have been widely used in the field of tissue engineering due to their ability to mimic the extracellular matrix of tissue. In addition to this, these macromolecules are found to have higher biocompatibility and no/lesser toxicity when compared to synthetic polymers. In recent years, scaffolds made up of proteins, polysaccharides, or glycoproteins have been highly used due to their tensile strength, biodegradability, and flexibility. This review is about the fabrication methods and applications of scaffolds made using various biological macromolecules, including polysaccharides like chitosan, agarose, cellulose, and dextran and proteins like soy proteins, zein proteins, etc. Biopolymer-based nanocomposite production and its application and limitations are also discussed in this review. This review also emphasizes the importance of using natural polymers rather than synthetic ones for developing scaffolds, as natural polymers have unique properties, like high biocompatibility, biodegradability, accessibility, stability, absence of toxicity, and low cost.

Fabrication of succinate-alginate xerogel films for in vitro coupling of osteogenesis and neovascularization

The osseointegration of metallic implants is reliant on a cascade of molecular interactions and the delivery of macromolecules to the implant environment that occurs before substantial bone formation. Early blood vessel formation is a requisite first step in the healing timeline for osteoid formation, where vascular development can be accelerated as a result of controlled hypoxic conditioning. In this study, alginate-derived xerogel films containing varied concentrations of disodium succinate salt which has been shown to induce pseudohypoxia (short-term hypoxic effects while maintaining an oxygenated environment) were developed. Xerogels were characterized for their morphology, succinate release over time and cellular response with osteoblast-mimicking Saos-2 and human umbilical vein endothelial cells (HUVEC). Scanning electron microscopy revealed a multiscale topography that may favour osseointegration and alamarBlue assays indicated no cytotoxic effects during in vitro proliferation of Saos-2 cells. pH measurements of eluted succinate reach 95 % of peak value after 7 h of immersion for all gels containing 10 mM of succinate or less, and 60 % within the first 40 min. In vitro exposure of HUVECs to succinate-conditioned media increased the net concentration of total proteins measured by bicinchoninic acid (BCA) assay and maintains stable vascular endothelial growth factor (VEGF) and extracellular platelet-derived growth factor (PDGF) for vessel formation through comparison of enzyme-linked immunosorbent assays (ELISAs) of the culture media and cell lysate. Tube formation assays also showed a sustained increase in tube diameter across the first 48 h of HUVEC culture when succinate concentrations of 1 and 10 μM in the xerogel. Overall, the succinate-alginate films serve as a prospective organic coating for bone-interfacing implant materials which may induce temporary pseudohypoxic conditions favourable for early angiogenesis and bone regeneration in vivo at succinate concentrations of 1 or 10 μM.

Growth Factor and Cytokine Delivery Systems for Wound Healing

Skin wound healing is a highly coordinated process involving multiple tissue-resident and recruited cell types. Cells within the wound microenvironment respond to key secreted factors such as pro-proliferative growth factors and immunomodulatory cytokines to repair the skin and promptly restore its essential barrier role. Therefore, recombinant growth factors and cytokines are promising therapeutics for skin wounds, in particular for large acute wounds such as burns, or wounds associated with underlying pathologies such as nonhealing chronic and diabetic wounds. However, translation of growth factors and cytokines into clinically effective treatments has been limited. Short half-life, poor stability, rapid diffusion, uncontrolled signaling, and systemic side effects are currently the key challenges to developing efficient growth factor- and cytokine-based therapies. To overcome these limitations, novel delivery systems have been developed to improve the regenerative potential of recombinant growth factors and cytokines. In this review, we discuss biomaterial and protein engineering strategies used to optimize the delivery of growth factor and cytokine therapeutics for skin wound treatment.

Synthesis of self-assembled hyaluronan based nanoparticles and their applications in targeted imaging and therapy

Hyaluronan (HA) is a polysaccharide consisting of repeating disaccharides of N-acetyl-d-glucosamine and d-glucuronic acid. There are increasing interests in utilizing self-assembled HA nanoparticles (HA-NPs) for targeted imaging and therapy. The principal endogenous receptor of HA, cluster of differentiation 44 (CD44), is overexpressed on many types of tumor cells as well as inflammatory cells in human bodies. Active targeting from HA-CD44 mediated interaction and passive targeting due to the enhanced permeability retention (EPR) effect could lead to selective accumulation of HA-NPs at targeted disease sites. This review focuses on the synthesis strategies of self-assembled HA-NPs, as well as their applications in therapy and biomedical imaging.

Combination of Hyaluronan and Lyophilized Progenitor Cell Derivatives: Stabilization of Functional Hydrogel Products for Therapeutic Management of Tendinous Tissue Disorders

Cultured progenitor cells and derivatives have been used in various homologous applications of cutaneous and musculoskeletal regenerative medicine. Active pharmaceutical ingredients (API) in the form of progenitor cell derivatives such as lysates and lyophilizates were shown to retain function in controlled cellular models of wound repair. On the other hand, hyaluronan-based hydrogels are widely used as functional vehicles in therapeutic products for tendon tissue disorders. The aim of this study was the experimental characterization of formulations containing progenitor tenocyte-derived APIs and hyaluronan, for the assessment of ingredient compatibility and stability in view of eventual therapeutic applications in tendinopathies. Lyophilized APIs were determined to contain relatively low quantities of proteins and growth factors, while being physicochemically stable and possessing significant intrinsic antioxidant properties. Physical and rheological quantifications of the combination formulas were performed after hydrogen peroxide challenge, outlining significantly improved evolutive viscoelasticity values in accelerated degradation settings. Thus, potent effects of physicochemical protection or stability enhancement of hyaluronan by the incorporated APIs were observed. Finally, combination formulas were found to be easily injectable into ex vivo tendon tissues, confirming their compatibility with further translational clinical approaches. Overall, this study provides the technical bases for the development of progenitor tenocyte derivative-based injectable therapeutic products or devices, to potentially be applied in tendinous tissue disorders.

Erythropoietin, as a biological macromolecule in modification of tissue engineered constructs: A review

In recent years, tissue engineering has emerged as a promising approach to address limitations of organ transplantation. The ultimate goal of tissue engineering is to provide scaffolds that closely mimic the physicochemical and biological cues of native tissues' extracellular matrix. In this endeavor, new generation of scaffolds have been designed that utilize the incorporation of signaling molecules in order to improve cell recruitment, enhance angiogenesis, exert healing activities, and increase the engraftment of the scaffolds. Among different signaling molecules, the role of erythropoietin (EPO) in regenerative medicine is increasingly being appreciated. It is a biological macromolecule which can prevent programed cell death, modulate inflammation, induce cell proliferation, and provide tissue protection in different disease models. In this review, we have outlined and critically analyzed different techniques of scaffolds' modification with EPO or EPO-loaded nanoparticles. We have also explored different strategies for the incorporation of EPO into scaffolds. Non-hematopoietic functions of EPO have also been discussed. Finalizing with detailed discussion surrounding the applications, challenges, and future perspectives of EPO-modified scaffolds in regenerative medicine.

Chitosan nanoparticles as a promising tool in nanomedicine with particular emphasis on oncological treatment

The study describes the current state of knowledge on nanotechnology and its utilization in medicine. The focus in this manuscript was on the properties, usage safety, and potentially valuable applications of chitosan-based nanomaterials. Chitosan nanoparticles have high importance in nanomedicine, biomedical engineering, discovery and development of new drugs. The manuscript reviewed the new studies regarding the use of chitosan-based nanoparticles for creating new release systems with improved bioavailability, increased specificity and sensitivity, and reduced pharmacological toxicity of drugs. Nowadays, effective cancer treatment is a global problem, and recent advances in nanomedicine are of great importance. Special attention was put on the application of chitosan nanoparticles in developing new system for anticancer drug delivery. Pre-clinical and clinical studies support the use of chitosan-based nanoparticles in nanomedicine. This manuscript overviews the last progresses regarding the utilization, stability, and bioavailability of drug nanoencapsulation with chitosan and their safety.

Fundamental and Practical Aspects in the Formulation of Colloidal Polyelectrolyte Complexes of Chitosan and siRNA

The formation of electrostatic interactions between polyanionic siRNA and polycations gives an easy access to the formation of colloidal particles capable of delivering siRNA in vitro or in vivo. Among the polycations used for siRNA delivery, chitosan occupies a special place due to its unique physicochemical and biological properties. In this chapter we describe the fundamental and practical aspects of the formation of colloidal complexes between chitosan and siRNA. The basis of the electrostatic complexation between oppositely charged polyelectrolytes is first introduced with a focus on the specific conditions to obtain stable colloid complex particles. Subsequent, the properties that make chitosan so special are described. In a third part, the main parameters influencing the colloidal properties and stability of siRNA/chitosan complexes are reviewed with emphasis on some practical aspects to consider in the preparation of complexes.

Polysaccharide nanoparticles: from fabrication to applications

The present review highlights the developments in polysaccharide nanoparticles with a particular focus on applications in biomedicine, cosmetics and food.

On-Chip Synthesis of Hyaluronic Acid-Based Nanoparticles for Selective Inhibition of CD44+ Human Mesenchymal Stem Cell Proliferation

In this study, an innovative microfluidics-based method was developed for one-step synthesis of hyaluronic acid (HA)-based nanoparticles (NPs), by exploiting polyelectrolytic interactions between HA and chitosan (CS), in order to improve reliability, reproducibility and possible scale-up of the NPs preparation. The on-chip synthesis, using a staggered herringbone micromixer, allowed to produce HA/CS NPs with tailored-made size and suitable for both parenteral (117.50 ± 4.51 nm) and loco-regional (349.15 ± 38.09 nm) administration, mainly composed by HA (more than 85% wt) with high negative surface charge (< −20 mV). HA/CS NPs were successfully loaded with a challenging water-insoluble molecule, Everolimus (EVE), an FDA- and EMA-approved anticancer drug able to lead to cell cycle arrest, reduced angiogenesis and promotion of apoptosis. HA/CS NPs resulted to be massively internalized in CD44+ human mesenchymal stem cells via CD44 receptor-mediated endocytosis. HA/CS NPs selectiveness towards CD44 was highlighted by blocking CD44 receptor by anti-CD44 primary antibody and by comparison to CS-based NPs cellular uptake. Eventually, high effectiveness in inhibiting cell proliferation was demonstrated on-chip synthetized EVE loaded HA/CS NPs by tracking in vitro DNA synthesis.

On the Formation and Stability of Chitosan/Hyaluronan-Based Complex Coacervates

This contribution is aimed at extending our previous findings on the formation and stability of chitosan/hyaluronan-based complex coacervates. Colloids are herewith formed by harnessing electrostatic interactions between the two polyelectrolytes. The presence of tiny amounts of the multivalent anion tripolyphosphate (TPP) in the protocol synthesis serves as an adjuvant “point-like” cross-linker for chitosan. Hydrochloride chitosans at different viscosity average molar mass, Mv¯, in the range 10,000–400,000 g/mol, and fraction of acetylated units, F_A, (0.16, 0.46 and 0.63) were selected to fabricate a large library of formulations. Concepts such as coacervate size, surface charge and homogeneity in relation to chitosan variables are herein disclosed. The stability of coacervates in Phosphate Buffered Saline (PBS) was verified by means of scattering techniques, i.e., Dynamic Light Scattering (DLS) and Small-Angle X-ray Scattering (SAXS). The conclusions from this set of experiments are the following: (i) a subtle equilibrium between chitosan F_A and Mv¯ does exist in ensuring colloidal stability; (ii) once diluted in PBS, osmotic swelling-driven forces trigger the enlargement of the polymeric mesh with an ensuing increase of coacervate size and porosity.

Glycosaminoglycan-based biomaterials for growth factor and cytokine delivery: Making the right choices

Controlled, localized drug delivery is a long-standing goal of medical research, realization of which could reduce the harmful side-effects of drugs and allow more effective treatment of wounds, cancers, organ damage and other diseases. This is particularly the case for protein "drugs" and other therapeutic biological cargoes, which can be challenging to deliver effectively by conventional systemic administration. However, developing biocompatible materials that can sequester large quantities of protein and release them in a sustained and controlled manner has proven challenging. Glycosaminoglycans (GAGs) represent a promising class of bio-derived materials that possess these key properties and can additionally potentially enhance the biological effects of the delivered protein. They are a diverse group of linear polysaccharides with varied functionalities and suitabilities for different cargoes. However, most investigations so far have focused on a relatively small subset of GAGs - particularly heparin, a readily available, promiscuously-binding GAG. There is emerging evidence that for many applications other GAGs are in fact more suitable for regulated and sustained delivery. In this review, we aim to illuminate the beneficial properties of various GAGs with reference to specific protein cargoes, and to provide guidelines for informed choice of GAGs for therapeutic applications.

Nanomedicine as a putative approach for active targeting of hepatocellular carcinoma

The effectiveness of chemotherapy in hepatocellular carcinoma (HCC) is restricted by chemo-resistance and systemic side effects. To improve the efficacy and safety of chemotherapeutics in HCC management, scientists have attempted to deliver these drugs to malignant tissues using targeted carriers as nanoparticles (NPs). Among the three types of NPs targeting (active, passive, and stimuli-responsive), active targeting is the most commonly investigated in HCC treatment. Despite the observed promising results so far, clinical research on nanomedicine targeting for HCC treatment still faces many challenges.These include batch-to-batch physicochemical properties' variations, limiting large scale production and insufficient data on human and environmental toxicities. This review summarized the characteristics of different nanocarriers, ligands, targeted receptors on HCC cells and provided recommendations to overcome the challenges, facing this novel line of treatment for HCC.

Biomimetic proteoglycan nanoparticles for growth factor immobilization and delivery

The delivery of growth factors is often challenging due to their short half-life, low stability, and rapid deactivation. In native tissues, the sulfated residual of glycosaminoglycan (GAG) polymer chains of proteoglycans immobilizes growth factors through the proteoglycans'/proteins' complexation with nanoscale organization. These biological assemblies can influence growth factor-cell surface receptor interactions, cell differentiation, cell-cell signaling, and mechanical properties of the tissues. Here, we introduce a facile procedure to prepare novel biomimetic proteoglycan nanocarriers, based on naturally derived polymers, for the immobilization and controlled release of growth factors. We developed polyelectrolyte complex nanoparticles (PCNs) as growth factor nanocarriers, which mimic the dimensions, chemical composition, and growth factor immobilization of proteoglycans in native tissues. PCNs were prepared by a polymer-polymer pair reaction method and characterized for physicochemical properties. Fourier transform infrared spectroscopy (FTIR) analysis indicated that complexation occurred through electrostatic interactions. Transmission electron microscopy (TEM) results showed that the nanocarriers had a diameter of 60 ± 11 nm and 91 ± 33 nm for dermatan sulfate sodium salt-poly-l-lysine (DS-PLL) and gum tragacanth-poly-l-lysine (GT-PLL) complexes, respectively. The colloidal nanoparticles were stable due to their negative zeta potential, i.e.-25 ± 4 mV for DS-PLL and -18 ± 3.5 mV for GT-PLL. Cytocompatibility of PCNs in contact with human bone marrow stromal cells (HS-5) was confirmed through a live/dead assay and metabolic activity measurement. In addition, vascular endothelial growth factor (VEGF) was used to evaluate the ability of PCNs to stabilize growth factors. The capability of PCNs to preserve VEGF activity for up to 21 days was confirmed by analyzing the metabolic and mitogenic characteristics of human umbilical vein endothelial cells (HUVECs). Our results demonstrated the potential applications of these nanoparticles in therapeutic delivery for tissue regeneration applications.

Chitosan Acetylation Degree Influences the Physical Properties of Polysaccharide Nanoparticles: Implication for the Innate Immune Cells Response

The aim of the present contribution is twofold as it reports (i) on the role played by chitosan acetylation degree for the stability of nanoparticles (NPs) formed with hyaluronan and (ii) on the effect of the interaction of such NPs with immune cells. Chitosans with similar viscosity-average molecular weight, [Formula: see text], (i.e., 200 000) and different fractions of acetylated units ( F_A) together with low-molecular-weight hyaluronan were chosen for developing a select library of formulations via electrostatic complex coacervation. The resulting NPs were analyzed in terms of size, polydispersity, surface charge, and stability in physiological-mimicked media by dynamic light scattering. Only medium acetylated chitosan ( F_A = 0.16) guaranteed the stability of NPs. To explore the effect of NPs interaction with immune cells, the release of proinflammatory cytokines and the reactive oxygen species production by human macrophages and neutrophils, respectively, were evaluated. Strikingly, a structure-function relationship emerged, showing that NPs made of chitosans with F_A = 0.02, 0.25, 0.46, and 0.63 manifested a proinflammatory activity, linked to the instability of the system. Conversely, NPs made of chitosan with F_A = 0.16 neither modified the functional response of macrophages nor that of neutrophils. Of note, such NPs were found to possess additional properties potentially advantageous in applications such as delivery of therapeutics to target inflamed sites: (i) they are devoid of cytotoxic effects, (ii) they avoid engulfment during the early stage of interaction with macrophages, and (iii) they are muco-adhesive, thereby providing for site-specificity and long-residence effects.

Cabazitaxel and silibinin co-encapsulated cationic liposomes for CD44 targeted delivery: A new insight into nanomedicine based combinational chemotherapy for prostate cancer

Cancer stem cells (CSCs) are the promising targets for cancer chemotherapy that cannot be eliminated by conventional chemotherapy. In this study cationic liposomes of cabazitaxel (CBX) and silibinin (SIL) were prepared with an aim to kill cancer cells and CSCs for prostate cancer. CBX act as cancer cell inhibitor and SIL as CSC inhibitor. Hyaluronic acid (HA), an endogenous anionic polysaccharide was coated on cationic liposomes for targeting CD44 receptors over expressed on CSCs. Liposomes were prepared by ethanol injection method with particle size below 100 nm and entrapment efficiency of more than 90% at 10% w/w drug loading. Liposomes were characterized by dynamic light scattering, transmission electron microscopy, ¹H nuclear magnetic resonance and scanning electron microscopy-energy dispersive x-ray spectroscopy. Liposomes were evaluated for their anticancer action in androgen independent human prostate cancer cell lines (PC-3 and DU-145). HA coated liposomes showed potential cytotoxicity over other groups with low IC₅₀, significantly inhibited cell migration and induced apoptosis. Synergistic cytotoxic effect was also observed with HA coated liposomes that resulted in colony formation inhibition and G2/M phase arrest. Proficient cytotoxicity against CD44⁺ cells (14.87 ± 0.41% in PC-3 and 33.95 ± 0.68% in DU-145 cells) indicated the efficiency of HA coated liposomes towards CSC targeting. Hence, the outcome of this combinational therapy with CD44 targeting indicates the suitability of HA coated CBX and SIL co-loaded liposomes as a potential approach for eradicating prostate cancer and herein might provide a insight for future studies.

The Microfluidic Technique and the Manufacturing of Polysaccharide Nanoparticles

The microfluidic technique has emerged as a promising tool to accelerate the clinical translation of nanoparticles, and its application affects several aspects, such as the production of nanoparticles and the in vitro characterization in the microenvironment, mimicking in vivo conditions. This review covers the general aspects of the microfluidic technique and its application in several fields, such as the synthesis, recovering, and samples analysis of nanoparticles, and in vitro characterization and their in vivo application. Among these, advantages in the production of polymeric nanoparticles in a well-controlled, reproducible, and high-throughput manner have been highlighted, and detailed descriptions of microfluidic devices broadly used for the synthesis of polysaccharide nanoparticles have been provided. These nanoparticulate systems have drawn attention as drug delivery vehicles over many years; nevertheless, their synthesis using the microfluidic technique is still largely unexplored. This review deals with the use of the microfluidic technique for the synthesis of polysaccharide nanoparticles; evaluating features of the most studied polysaccharide drug carriers, such as chitosan, hyaluronic acid, and alginate polymers. The critical assessment of the most recent research published in literature allows us to assume that microfluidics will play an important role in the discovery and clinical translation of nanoplatforms.

Concepts for Developing Physical Gels of Chitosan and of Chitosan Derivatives

Chitosan macro- and micro/nano-gels have gained increasing attention in recent years, especially in the biomedical field, given the well-documented low toxicity, degradability, and non-immunogenicity of this unique biopolymer. In this review we aim at recapitulating the recent gelling concepts for developing chitosan-based physical gels. Specifically, we describe how nowadays it is relatively simple to prepare networks endowed with different sizes and shapes simply by exploiting physical interactions, namely (i) hydrophobic effects and hydrogen bonds-mostly governed by chitosan chemical composition-and (ii) electrostatic interactions, mainly ensured by physical/chemical chitosan features, such as the degree of acetylation and molecular weight, and external parameters, such as pH and ionic strength. Particular emphasis is dedicated to potential applications of this set of materials, especially in tissue engineering and drug delivery sectors. Lastly, we report on chitosan derivatives and their ability to form gels. Additionally, we discuss the recent findings on a lactose-modified chitosan named Chitlac, which has proved to form attractive gels both at the macro- and at the nano-scale.

Design of spherically structured 3D in vitro tumor models -Advances and prospects

Three-dimensional multicellular tumor models are receiving an ever-growing focus as preclinical drug-screening platforms due to their potential to recapitulate major physiological features of human tumors in vitro. In line with this momentum, the technologies for assembly of 3D microtumors are rapidly evolving towards a comprehensive inclusion of tumor microenvironment elements. Customized spherically structured platforms, including microparticles and microcapsules, provide a robust and scalable technology to imprint unique biomolecular tumor microenvironment hallmarks into 3D in vitro models. Herein, a comprehensive overview of novel advances on the integration of tumor-ECM components and biomechanical cues into 3D in vitro models assembled in spherical shaped platforms is provided. Future improvements regarding spatiotemporal/mechanical adaptability, and degradability, during microtumors in vitro 3D culture are also critically discussed considering the realistic potential of these platforms to mimic the dynamic tumor microenvironment. From a global perspective, the production of 3D multicellular spheroids with tumor ECM components included in spherical models will unlock their potential to be used in high-throughput screening of therapeutic compounds. It is envisioned, in a near future, that a combination of spherically structured 3D microtumor models with other advanced microfluidic technologies will properly recapitulate the flow dynamics of human tumors in vitro.

STATEMENT OF SIGNIFICANCE

The ability to correctly mimic the complexity of the tumor microenvironment in vitro is a key aspect for the development of evermore realistic in vitro models for drug-screening and fundamental cancer biology studies. In this regard, conventional spheroid-based 3D tumor models, combined with spherically structured biomaterials, opens the opportunity to precisely recapitulate complex cell-extracellular matrix interactions and tumor compartmentalization. This review provides an in-depth focus on current developments regarding spherically structured scaffolds engineered into in vitro 3D tumor models, and discusses future advances toward all-encompassing platforms that may provide an improved in vitro/in vivo correlation in a foreseeable future.

Polysaccharide-Based Controlled Release Systems for Therapeutics Delivery and Tissue Engineering: From Bench to Bedside

Polysaccharides or polymeric carbohydrate molecules are long chains of monosaccharides that are linked by glycosidic bonds. The naturally based structural materials are widely applied in biomedical applications. This article covers four different types of polysaccharides (i.e., alginate, chitosan, hyaluronic acid, and dextran) and emphasizes their chemical modification, preparation approaches, preclinical studies, and clinical translations. Different cargo fabrication techniques are also presented in the third section. Recent progresses in preclinical applications are then discussed, including tissue engineering and treatment of diseases in both therapeutic and monitoring aspects. Finally, clinical translational studies with ongoing clinical trials are summarized and reviewed. The promise of new development in nanotechnology and polysaccharide chemistry helps clinical translation of polysaccharide-based drug delivery systems.

Butyrate-Loaded Chitosan/Hyaluronan Nanoparticles: A Suitable Tool for Sustained Inhibition of ROS Release by Activated Neutrophils

Tissue damage caused by excessive amounts of neutrophil-derived reactive oxygen species (ROS) occurs in many inflammatory diseases. Butyrate is a short-chain fatty acid (SCFA) with known anti-inflammatory properties, able to modulate several neutrophil functions. Evidence is provided here that butyrate inhibits neutrophil ROS release in a dose and time-dependent fashion. Given the short half-life of butyrate, chitosan/hyaluronan nanoparticles are next designed and developed as controlled release carriers able to provide cells with a long-lasting supply of this SCFA. Notably, while the inhibition of neutrophil ROS production by free butyrate declines over time, that of butyrate-loaded chitosan/hyaluronan nanoparticles (B-NPs) is sustained. Additional valuable features of these nanoparticles are inherent ROS scavenger activity, resistance to cell internalization, and mucoadhesiveness. B-NPs appear as promising tools to limit ROS-dependent tissue injury during inflammation. Particularly, by virtue of their mucoadhesiveness, B-NPs administered by enema can be effective in the treatment of inflammatory bowel diseases.

Effects of a Bioactive Scaffold Containing a Sustained Transforming Growth Factor-β1-releasing Nanoparticle System on the Migration and Differentiation of Stem Cells from the Apical Papilla

INTRODUCTION

This 2-part study hypothesized that a bioactive scaffold containing a sustained transforming growth factor (TGF)-β1-releasing nanoparticle system will promote migration and enhance differentiation of stem cells from the apical papilla (SCAP). The study aimed to develop and characterize a novel modified chitosan-based scaffold containing TGF-β1-releasing chitosan nanoparticles (TGF-β1-CSnp) to enhance migration and differentiation of SCAP.

METHODS

Part I concerns the synthesis and characterization of a carboxymethyl chitosan-based scaffold and TGF-β1-CSnp. Part II examines the effect of sustained TGF-β1 release from scaffold containing TGF-β1-CSnp on odontogenic differentiation of SCAP.

RESULTS

The scaffold demonstrated properties conducive to cellular activities. The incorporation of TGF-β1 in CSnp allowed sustained release of TGF-β1, facilitating delivery of a critical concentration of TGF-β1 at the opportune time. TGF-β1 bioactivity was maintained for up to 4 weeks. SCAP showed greater viability, migration, and biomineralization in the presence of TGF-β1-CSnp than in the presence of free TGF-β1. SCAP cultured in TGF-β1-CSnp + scaffold showed significantly higher dentin matrix protein-1 and dentin sialophosphoprotein signals compared with free TGF-β1 + scaffold or CSnp + scaffold.

CONCLUSIONS

These experiments highlighted the potential of a carboxymethyl chitosan-based scaffold with growth factor releasing nanoparticles to promote migration and differentiation of SCAP. The results of this study may have direct application to improve current endodontic regenerative protocols.

PLGA Microparticles Entrapping Chitosan-Based Nanoparticles for the Ocular Delivery of Ranibizumab

Age-related macular degeneration (AMD) is the leading cause of certified vision loss worldwide. The standard treatment for neovascular AMD involves repeated intravitreal injections of therapeutic proteins directed against vascular endothelial growth factor, such as ranibizumab. Biodegradable polymers, such as poly(lactic-co-glycolic acid) (PLGA), form delivery vehicles which can be used to treat posterior segment eye diseases, but suffer from poor protein loading and release. This work describes a "system-within-system", PLGA microparticles incorporating chitosan-based nanoparticles, for improved loading and sustained intravitreal delivery of ranibizumab. Chitosan-N-acetyl-l-cysteine (CNAC) was synthesized and its synthesis confirmed using FT-IR and (1)H NMR. Chitosan-based nanoparticles composed of CNAC, CNAC/tripolyphosphate (CNAC/TPP), chitosan, chitosan/TPP (chit/TPP), or chit/TPP-hyaluronic acid (chit/TPP-HA) were incorporated in PLGA microparticles using a modified w/o/w double emulsion method. Nanoparticles and final nanoparticles-within-microparticles were characterized for their protein-nanoparticle interaction, size, zeta potential, morphology, protein loading, stability, in vitro release, in vivo antiangiogenic activity, and effects on cell viability. The prepared nanoparticles were 17-350 nm in size and had zeta potentials of -1.4 to +12 mV. Microscopic imaging revealed spherical nanoparticles on the surface of PLGA microparticles for preparations containing chit/TPP, CNAC, and CNAC/TPP. Ranibizumab entrapment efficiency in the preparations varied between 13 and 69% and was highest for the PLGA microparticles containing CNAC nanoparticles. This preparation also showed the slowest release with no initial burst release compared to all other preparations. Incorporation of TPP to this formulation increased the rate of protein release and reduced entrapment efficiency. PLGA microparticles containing chit/TPP-HA showed the fastest and near-complete release of ranibizumab. All of the prepared empty particles showed no effect on cell viability up to a concentration of 12.5 mg/mL. Ranibizumab released from all preparations maintained its structural integrity and in vitro activity. The chit/TPP-HA preparation enhanced antiangiogenic activity and may provide a potential biocompatible platform for enhanced antiangiogenic activity in combination with ranibizumab. In conclusion, the PLGA microparticles containing CNAC nanoparticles showed significantly improved ranibizumab loading and release profile. This novel drug delivery system may have potential for improved intravitreal delivery of therapeutic proteins, thereby reducing the frequency, risk, and cost of burdensome intravitreal injections.

Nanoparticle drug delivery systems and their use in cardiac tissue therapy

Cardiovascular diseases make up one of the main causes of death today, with myocardial infarction and ischemic heart disease contributing a large share of the deaths reported. With mainstream clinical therapy focusing on palliative medicine following myocardial infarction, the structural changes that occur in the diseased heart will eventually lead to end-stage heart failure. Heart transplantation remains the only gold standard of cure but a shortage in donor organs pose a major problem that led to clinicians and researchers looking into alternative strategies for cardiac repair. This review will examine some alternative methods of treatment using chemokines and drugs carried by nanoparticles as drug delivering agents for the purposes of treating myocardial infarction through the promotion of revascularization. We will also provide an overview of existing studies involving such nanoparticulate drug delivery systems, their reported efficacy and the challenges facing their translation into ubiquitous clinical use.

Temporal-controlled Dexamethasone Releasing Chitosan Nanoparticle System Enhances Odontogenic Differentiation of Stem Cells from Apical Papilla

INTRODUCTION

The spatial and temporal control of stem cell differentiation into odontoblast-like cells remains one of the major challenges in regenerative endodontic procedures. The current study aims to synthesize and compare the effect of dexamethasone (Dex) release from 2 variants of Dex-loaded chitosan nanoparticles (CSnp) on the odontogenic differentiation of stem cells from apical papilla (SCAP).

METHODS

Two variants of Dex-loaded CSnp were synthesized by encapsulation (Dex-CSnpI) and adsorption (Dex-CSnpII) methods. The physicochemical characterization of Dex-CSnpI and Dex-CSnpII was assessed by transmission electron microscopy, Zetasizer, and Fourier transform infrared spectroscopy, whereas the Dex release kinetics was assessed by spectrophotometry. A previously characterized SCAP cell line was cultured onto CSnp, Dex-CSnpI, or Dex-CSnpII. The biomineralization potential was determined by alizarin red staining. Alkaline phosphatase, dentin sialophosphoprotein, and dentin matrix protein-1 gene expressions were analyzed by real-time reverse-transcription polymerase chain reaction.

RESULTS

Dex-CSnpI resulted in slower release of Dex compared with Dex-CSnpII, but both demonstrated sustained release of Dex for 4 weeks. Biomineralization of SCAP was significantly higher (P < .05) in presence of Dex-CSnpII compared with that in Dex-CSnpI at 3 weeks. Alkaline phosphatase gene expression was significantly higher in the presence of Dex-CSnpII compared with Dex-CSnpI, with peak expression seen at 2 weeks (P < .05). The expression of odontogenic specific marker dentin matrix protein-1 was significantly higher in presence of Dex-CSnpII compared with Dex-CSnpI at 3 weeks (P < .05).

CONCLUSIONS

Collectively, these data suggest that sustained release of Dex results in enhanced odontogenic differentiation of SCAP. These findings highlight the potential of temporal-controlled delivery of bioactive molecules to direct the spatial- and temporal-controlled odontogenic differentiation of dental stem cells.

Rate-programming of nano-particulate delivery systems for smart bioactive scaffolds in tissue engineering

Development of smart bioactive scaffolds is of importance in tissue engineering, where cell proliferation, differentiation and migration within scaffolds can be regulated by the interactions between cells and scaffold through the use of growth factors (GFs) and extra cellular matrix peptides. One challenge in this area is to spatiotemporally control the dose, sequence and profile of release of GFs so as to regulate cellular fates during tissue regeneration. This challenge would be addressed by rate-programming of nano-particulate delivery systems, where the release of GFs via polymeric nanoparticles is controlled by means of the methods of, such as externally-controlled and physicochemically/architecturally-modulated so as to mimic the profile of physiological GFs. Identifying and understanding such factors as the desired release profiles, mechanisms of release, physicochemical characteristics of polymeric nanoparticles, and externally-triggering stimuli are essential for designing and optimizing such delivery systems. This review surveys the recent studies on the desired release profiles of GFs in various tissue engineering applications, elucidates the major release mechanisms and critical factors affecting release profiles, and overviews the role played by the mathematical models for optimizing nano-particulate delivery systems. Potentials of stimuli responsive nanoparticles for spatiotemporal control of GF release are also presented, along with the recent advances in strategies for spatiotemporal control of GF delivery within tissue engineered scaffolds. The recommendation for the future studies to overcome challenges for developing sophisticated particulate delivery systems in tissue engineering is discussed prior to the presentation of conclusions drawn from this paper.

Chemical functionalization of bone implants with nanoparticle-stabilized chitosan and methotrexate for inhibiting both osteoclastoma formation and bacterial infection

A great challenge in orthopedic tumor operation faced by orthopedic implants is the high recurrence and metastasis of bone tumor as well as the bacterial infection associated with the implants. Thus ideal titanium (Ti)-based bone implants should be able to not only inhibit cancer cell adhesion and proliferation, promote cancer cell apoptosis, but also resist bacterial infections. Towards this end, we developed a new approach to modify the surface of Ti-based bone implants so that they can restrain functions of osteoclastoma (Giant cell tumor of bone) cancer cells (GCTs) and inhibit the adhesion of bacteria. First, the surface of pristine Ti substrates was functionalized with dopamine (DA) to form DA-Ti substrates. Then nanoparticles electrostatically assembled from poly-lysine (PLL) and heparin (Hep) were chemically immobilized onto the DA-Ti substrates to form PLL/Hep-Ti substrates. Chitosan (CH) and methotrexate (MTX) were then electrostatically immobilized onto the PLL/Hep-Ti substrates to generate CH-MTX-Ti substrates. The successful functionalization of the Ti substrates was confirmed by X-ray photoelectron spectroscopy. GCTs cultured on differently functionalized Ti substrates were investigated in terms of cell adhesion, cytoskeleton, proliferation, cytotoxicity and apoptosis. The growth of Staphylococcus aureus bacteria in the presence of different substrates was also assayed. Our results showed that CH-MTX-Ti substrates not only significantly inhibited the adhesion, proliferation and viability of GCTs, promoted the apoptosis of GCTs, but also prevented the adhesion of the bacteria and the subsequent formation of bacterial biofilms, when compared to other Ti substrates. Thus CH-MTX-Ti substrates are expected to be used as orthopedic prostheses in bone tumor surgery that can inhibit both osteoclastoma formation and bacterial infections.

Injectable in situ forming hybrid iron oxide-hyaluronic acid hydrogel for magnetic resonance imaging and drug delivery

The development of multimodal in situ cross-linkable hyaluronic acid nanogels hybridized with iron oxide nanoparticles is reported. Utilizing a chemoselective hydrazone coupling reaction, the nanogels are converted to a macroscopic hybrid hydrogel without any additional reagent. Hydrophobic cargos remain encapsulated in the hydrophobic domains of the hybrid hydrogel without leakage. However, hydrogel degradation with hyaluronidase liberates iron oxide nanoparticles. This allows the utilization of imaging agents as tracers of the hydrogel degradation. UV-vis spectrometry and MRI studies reveal that the degradability of the hydrogels correlates with their structure. The hydrogels presented here are very promising theranostic tools for hyaluronidase-mediated delivery of hydrophobic drugs, as well as imaging of hydrogel degradation and tracking of degradation products in vivo.

Temporal-controlled release of bovine serum albumin from chitosan nanoparticles: effect on the regulation of alkaline phosphatase activity in stem cells from apical papilla

INTRODUCTION

The controlled delivery of bioactive molecules is crucial for the regulation of stem cell differentiation. In this study, we examined the effects of temporal-controlled release of bovine serum albumin (BSA) from chitosan nanoparticles (CSnp) to regulate the alkaline phosphatase activity (ALP) in stem cells from apical papilla (SCAP).

METHODS

BSA-loaded CSnp were synthesized by 2 methods to achieve the variant temporal-controlled release: (1) the encapsulation technique (BSA-CSnpI) and (2) the adsorption technique (BSA-CSnpII). After characterization of the size, charge, and release kinetics, SCAP were cultured in the presence of these bioactive molecule-loaded nanoparticles. SCAP viability was analyzed at 1, 7, 14, 21, and 28 days, and ALP activity was analyzed every 7 days until 21 days to determine the effect of these bioactive molecule-releasing nanoparticles on the cytotoxicity and differentiation potential, respectively.

RESULTS

BSA-CSnpI and BSA-CSnpII presented distinct in vitro release profiles of BSA in a time-controlled manner. Cell viability was significantly enhanced over time in the presence of BSA-CSnpI and BSA-CSnpII (P < .01), when compared with BSA nonloaded CSnp. ALP activity was significantly higher (P < .01) in the presence of BSA-CSnpI after 3 weeks than in BSA-CSnpII.

CONCLUSIONS

BSA-loaded CSnps were synthesized and characterized in this study. Based on the physical/chemical interaction of BSA with CSnp (encapsulation or surface adsorption), different time-controlled release profiles were observed that influenced the ALP activity of SCAP in vitro. This study highlighted the potential of temporal-controlled bioactive molecule release technology in the differentiation of stem cells in dentin pulp regeneration.

Angiogenic therapy for cardiac repair based on protein delivery systems

Cardiovascular diseases remain the first cause of morbidity and mortality in the developed countries and are a major problem not only in the western nations but also in developing countries. Current standard approaches for treating patients with ischemic heart disease include angioplasty or bypass surgery. However, a large number of patients cannot be treated using these procedures. Novel curative approaches under investigation include gene, cell, and protein therapy. This review focuses on potential growth factors for cardiac repair. The role of these growth factors in the angiogenic process and the therapeutic implications are reviewed. Issues including aspects of growth factor delivery are presented in relation to protein stability, dosage, routes, and safety matters. Finally, different approaches for controlled growth factor delivery are discussed as novel protein delivery platforms for cardiac regeneration.