Heparinized chitosan/poly(γ-glutamic acid) nanoparticles for multi-functional delivery of fibroblast growth factor and heparin

Journey into tomorrow: cardiovascular wellbeing transformed by nano-scale innovations

Worldwide, cardiovascular diseases (CVDs) account for the vast majority of deaths and place enormous financial strains on healthcare systems. Gold nanoparticles, quantum dots, polymeric nanoparticles, carbon nanotubes, and lipids are innovative nanomaterials promising in tackling CVDs. In the setting of CVDs, these nanomaterials actively impact cellular responses due to their distinctive properties, including surface energy and topographies. Opportunities to more precisely target CVDs have arisen due to recent developments in nanomaterial science, which have introduced fresh approaches. An in-depth familiarity with the illness and its targeted mechanisms is necessary to use nanomaterials in CVDs effectively. We support the academic community's efforts to prioritize Nano-technological techniques in addressing risk factors linked with cardiovascular diseases, acknowledging the far-reaching effects of these conditions. The significant impact of nanotechnology on the early detection and treatment of cardiovascular diseases highlights the critical need for novel approaches to this pressing health problem, which is affecting people worldwide.

A Tunable Glycosaminoglycan-Peptide Nanoparticle Platform for the Protection of Therapeutic Peptides

The popularity of Glycosaminoglycans (GAGs) in drug delivery systems has grown as their innate ability to sequester and release charged molecules makes them adept in the controlled release of therapeutics. However, peptide therapeutics have been relegated to synthetic, polymeric systems, despite their high specificity and efficacy as therapeutics because they are rapidly degraded in vivo when not encapsulated. We present a GAG-based nanoparticle system for the easy encapsulation of cationic peptides, which offers control over particle diameter, peptide release behavior, and swelling behavior, as well as protection from proteolytic degradation, using a singular, organic polymer and no covalent linkages. These nanoparticles can encapsulate cargo with a particle diameter range spanning 130-220 nm and can be tuned to release cargo over a pH range of 4.5 to neutral through the modulation of the degree of sulfation and the molecular weight of the GAG. This particle system also confers better in vitro performance than the unencapsulated peptide via protection from enzymatic degradation. This method provides a facile way to protect therapeutic peptides via the inclusion of the presented binding sequence and can likely be expanded to larger, more diverse cargo as well, abrogating the complexity of previously demonstrated systems while offering broader tunability.

Multiscale design of stiffening and ROS scavenging hydrogels for the augmentation of mandibular bone regeneration

Although biomimetic hydrogels play an essential role in guiding bone remodeling, reconstructing large bone defects is still a significant challenge since bioinspired gels often lack osteoconductive capacity, robust mechanical properties and suitable antioxidant ability for bone regeneration. To address these challenges, we first engineered molecular design of hydrogels (gelatin/polyethylene glycol diacrylate/2-(dimethylamino)ethyl methacrylate, GPEGD), where their mechanical properties were significantly enhanced via introducing trace amounts of additives (0.5 wt%). The novel hybrid hydrogels show high compressive strength (>700 kPa), stiff modulus (>170 kPa) and strong ROS-scavenging ability. Furthermore, to endow the GPEGD hydrogels excellent osteoinductions, novel biocompatible, antioxidant and BMP-2 loaded polydopamine/heparin nanoparticles (BPDAH) were developed for functionalization of the GPEGD gels (BPDAH-GPEGD). In vitro results indicate that the antioxidant BPDAH-GPEGD is able to deplete elevated ROS levels to protect cells viability against ROS damage. More importantly, the BPDAH-GPEGD hydrogels have good biocompatibility and promote the osteo differentiation of preosteoblasts and bone regenerations. At 4 and 8 weeks after implantation of the hydrogels in a mandibular bone defect, Micro-computed tomography and histology results show greater bone volume and enhancements in the quality and rate of bone regeneration in the BPDAH-GPEGD hydrogels. Thus, the multiscale design of stiffening and ROS scavenging hydrogels could serve as a promising material for bone regeneration applications.

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Trace additives of DMAEMA markedly enhanced the mechanical performances of the gelatin-based hydrogels through molecular induced multiple crosslinking structures.

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Molecular design strategy combined with bioactive nanocomposites have a synergistically effects on promoting ROS scavenging ability and osteoactivity of the biomimetic hydrogels.

Physicochemical properties of electrostatically crosslinked carrageenan/chitosan hydrogels and carrageenan/chitosan/Laponite nanocomposite hydrogels

In this work physical carrageenan/chitosan (Car/Chit) hydrogels are prepared by electrostatic complexation between the two oppositely charged polysaccharides. The hydrogels have storage moduli in the order of 5-10 kPa and swelling ratios in the order of 5000-6000 %. At conditions where both polysaccharides are highly charged (pH 5) the swelling ratios are lower than the ones at conditions of lower dissociation i.e., at pH 2 and 7 and the opposite trend is found for the storage modulus. Chit appears to act as a crosslinker for Car as increasing its concentration the swelling ratio decreases and the moduli increase. The hydrogels can incorporate the nanoclay Laponite (Lap) and form hybrid nanocomposites where the intercalation by the two biopolymers leads to exfoliation of the clay nanoplatelets in the presence of both Car and Chit. The composite hydrogels retain the mechanical properties of the Car/Chit hydrogels at the studied pH range (pH 2 to pH 7). This shows the prepared hydrogels can be potentially used as multifunctional biomaterials for drug delivery, tissue engineering and bone regeneration applications.

Microalgae-Based Biohybrid Microrobot for Accelerated Diabetic Wound Healing

A variety of wound healing platforms have been proposed to alleviate the hypoxic condition and/or to modulate the immune responses for the treatment of chronic wounds in diabetes. However, these platforms with the passive diffusion of therapeutic agents through the blood clot result in the relatively low delivery efficiency into the deep wound site. Here, a microalgae-based biohybrid microrobot for accelerated diabetic wound healing is developed. The biohybrid microrobot autonomously moves at velocity of 33.3 µm s^-1 and generates oxygen for the alleviation of hypoxic condition. In addition, the microrobot efficiently bound with inflammatory chemokines of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) for modulating the immune responses. The enhanced penetration of microrobot is corroborated by measuring fibrin clots in biomimetic wound using microfluidic devices and the enhanced retention of microrobot is confirmed in the real wounded mouse skin tissue. After deposition on the chronic wound in diabetic mice without wound dressing, the wounds treated with microrobots are completely healed after 9 days with the significant decrease of inflammatory cytokines below 31% of the control level and the upregulated angiogenesis above 20 times of CD31⁺ cells. These results confirm the feasibility of microrobots as a next-generation platform for diabetic wound healing.

Synthesis and Characterization of Fucoidan-Chitosan Nanoparticles Targeting P-Selectin for Effective Atherosclerosis Therapy

Atherosclerosis is the key pathogenesis of cardiovascular diseases; oxidative stress, which is induced by the generated excess reactive oxygen species (ROS), has been a crucial mechanism underlying this pathology. Nanoparticles (NPs) represent a novel strategy for the development of potential therapies against atherosclerosis, and multifunctional NPs possessing antioxidative capacities hold promise for amelioration of vascular injury caused by ROS and for evading off-target effects; materials that are currently used for NP synthesis often serve as vehicles that do not possess intrinsic biological activities; however, they may affect the surrounding healthy environment due to decomposition of products. Herein, we used nontoxic fucoidan, a sulfated polysaccharide derived from a marine organism, to develop chitosan–fucoidan nanoparticles (CFNs). Then, by binding to P-selectin, an inflammatory adhesion exhibited molecule expression on the endothelial cells and activated platelets, blocking leukocyte recruitment and rolling on platelets and endothelium. CFNs exhibit antioxidant and anti-inflammatory properties. Nevertheless, by now, the application of CFNs for the target delivery regarding therapeutics specific to atherosclerotic plaques is not well investigated. The produced CFNs were physicochemically characterized using transmission electron microscopy (TEM), together with Fourier transform infrared spectroscopy (FTIR). Evaluations of the in vitro antioxidant as well as anti-inflammatory activities exhibited by CFNs were based on the measurement of their ROS scavenging abilities and investigating inflammatory mediator levels. The in vivo pharmacokinetics and binding efficiency of the CFNs to atherosclerotic plaques were also evaluated. The therapeutic effects indicated that CFNs effectively suppressed local oxidative stress and inflammation by targeting P-selectin in atheromatous plaques and thereby preventing the progression of atherosclerosis.

Static and Dynamic Biomaterial Engineering for Cell Modulation

In the biological microenvironment, cells are surrounded by an extracellular matrix (ECM), with which they dynamically interact during various biological processes. Specifically, the physical and chemical properties of the ECM work cooperatively to influence the behavior and fate of cells directly and indirectly, which invokes various physiological responses in the body. Hence, efficient strategies to modulate cellular responses for a specific purpose have become important for various scientific fields such as biology, pharmacy, and medicine. Among many approaches, the utilization of biomaterials has been studied the most because they can be meticulously engineered to mimic cellular modulatory behavior. For such careful engineering, studies on physical modulation (e.g., ECM topography, stiffness, and wettability) and chemical manipulation (e.g., composition and soluble and surface biosignals) have been actively conducted. At present, the scope of research is being shifted from static (considering only the initial environment and the effects of each element) to biomimetic dynamic (including the concepts of time and gradient) modulation in both physical and chemical manipulations. This review provides an overall perspective on how the static and dynamic biomaterials are actively engineered to modulate targeted cellular responses while highlighting the importance and advance from static modulation to biomimetic dynamic modulation for biomedical applications.

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

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

Resveratrol-Loaded TPGS-Resveratrol-Solid Lipid Nanoparticles for Multidrug-Resistant Therapy of Breast Cancer: In Vivo and In Vitro Study

Multidrug resistance (MDR) is a serious problem during cancer therapy. The purpose of the present study was to formulate D-α-Tocopheryl polyethylene glycol 1000 succinate-resveratrol-solid lipid nanoparticles (TPGS-Res-SLNs) to improve its therapeutic efficacy against breast cancer. In this study, the solvent injection method was used to prepare the TPGS-Res-SLNs. It was found that the TPGS-Res-SLNs exhibited zeta potential and drug-loading of -25.6 ± 1.3 mV and 32.4 ± 2.6%, respectively. Therefore, it was evident that the TPGS-Res-SLNs can increase cellular uptake of chemotherapeutic drugs, induce mitochondrial dysfunction, and augment tumor treatment efficiency by inducing apoptosis. Moreover, it was found that SKBR3/PR cells treated with TPGS-Res-SLNs exhibited significant inhibition of cell migration and invasion, as compared with free resveratrol. In addition, results from in vivo SKBR3/PR xenograft tumor models revealed that TPGS-Res-SLNs has better efficacy in promoting apoptosis of tumor cells owing to high therapeutic outcomes on tumors when compared with the efficacy of free resveratrol. In conclusion, the findings of the present study indicate significant potential for use of TPGS-Res-SLNs as an efficient drug delivery vehicle to overcome drug resistance in breast cancer therapy.

Polysaccharide-based nanomedicines for cancer immunotherapy: A review

Cancer immunotherapy is an effective antitumor approach through activating immune systems to eradicate tumors by immunotherapeutics. However, direct administration of "naked" immunotherapeutic agents (such as nucleic acids, cytokines, adjuvants or antigens without delivery vehicles) often results in: (1) an unsatisfactory efficacy due to suboptimal pharmacokinetics; (2) strong toxic and side effects due to low targeting (or off-target) efficiency. To overcome these shortcomings, a series of polysaccharide-based nanoparticles have been developed to carry immunotherapeutics to enhance antitumor immune responses with reduced toxicity and side effects. Polysaccharides are a family of natural polymers that hold unique physicochemical and biological properties, as they could interact with immune system to stimulate an enhanced immune response. Their structures offer versatility in synthesizing multifunctional nanocomposites, which could be chemically modified to achieve high stability and bioavailability for delivering therapeutics into tumor tissues. This review aims to highlight recent advances in polysaccharide-based nanomedicines for cancer immunotherapy and propose new perspectives on the use of polysaccharide-based immunotherapeutics.

Blood biocompatibility enhancement of biomaterials by heparin immobilization: a review

Blood contacting materials are concerned with biocompatibility including thrombus formation, decrease blood coagulation time, hematology, activation of complement system, platelet aggression. Interestingly, recent research suggests that biocompatibility is increasing by incorporating various materials including heparin using different methods. Basic of heparin including uses and complications was mentioned, in which burst release of heparin is major issue. To minimize the problem of biocompatibility and unpredictable heparin release, present review article potentially reviews the reported work and investigates the various immobilization methods of heparin onto biomaterials, such as polymers, metals, and alloys. Detailed explanation of different immobilization methods through different intermediates, activation, incubation method, plasma treatment, irradiations and other methods are also discussed, in which immobilization through intermediates is the most exploitable method. In addition to biocompatibility, other required properties of biomaterials like mechanical and corrosion resistance properties that increase by attachment of heparin are reviewed and discussed in this article.

Preparation and characterization of ferulic acid-modified water soluble chitosan and poly (γ-glutamic acid) polyelectrolyte films through layer-by-layer assembly towards protein adsorption

In this study, ferulic acid-modified water soluble chitosan and poly (γ-glutamic acid) polyelectrolyte multilayers films were constructed through the layer-by-layer (LBL) self-assembly technique. Chitosan (CS) or ferulic acid modified chitosan (MCS) and Poly (γ-glutamic acid) (PGA) was alternately deposited on the surface of glass substrate for the enhancement of surface modification. The obtained films were characterized by Fourier transform spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and water contact angle to study its physico-chemical properties including protein absorption. The (PGA/MCS) films showed intense deposition of multilayers built upon the surface roughness and an increase in the exponential growth of multilayer films by UV-vis spectroscopy. Water contact angle indicated that the (PGA/MCS) films performed well with good wettability due to the increase in the number of layers. The LBL multilayer coatings of (PGA/MCS) films surface possessed a reduced amount of protein adsorption. These results indicated that it can resist the protein adsorption and can enhance the biocompatibility towards the biomedical application through the protein interaction. The (PGA/MCS) films has the potential to utilization as a good biomaterial for biomedical purposes to intensify the bio-active surface.

Engineered biomaterial strategies for controlling growth factors in tissue engineering

Growth factors are multi-functional signaling molecules that coordinate multi-stage process of wound healing. During wound healing, growth factors are transmitted to wound environment in a positive and physiologically related way, therefore, there is a broad prospect for studying the mediated healing process through growth factors. However, growth factors (GFs) themselves have disadvantages of instability, short life, rapid inactivation of physiological conditions, low safety and easy degradation, which hinder the clinical use of GFs. Rapid development of delivery strategies for GFs has been trying to solve the instability and insecurity of GFs. Particularly, in recent years, GFs delivered by scaffolds based on biomaterials have become a hotspot in this filed. This review introduces various delivery strategies for growth factors based on new biodegradable materials, especially polysaccharides, which could provide guidance for the development of the delivery strategies for growth factors in clinic.

Drug nanodelivery systems based on natural polysaccharides against different diseases

Drug nanodelivery systems (DNDSs) are fascinated cargos to achieve outstanding therapeutic results of various drugs or natural bioactive compounds owing to their unique structures. The efficiency of several pharmaceutical drugs or natural bioactive ingredients is restricted because of their week bioavailability, poor bioaccessibility and pharmacokinetics after orally pathways. In order to handle such constraints, usage of native/natural polysaccharides (NPLS) in fabrication of DNDSs has gained more popularity in the arena of nanotechnology for controlled drug delivery to enhance safety, biocompatibility, better retention time, bioavailability, lower toxicity and enhanced permeability. The main commonly used NPLS in nanoencapsulation systems include chitosan, pectin, alginates, cellulose, starches, and gums recognized as potential materials for fabrication of cargos. Herein, this review is centered on different polysaccharide-based nanocarriers including nanoemulsions, nanohydrogels, nanoliposomes, nanoparticles and nanofibers, which have already served as encouraging candidates for entrapment of therapeutic drugs as well as for their sustained controlled release. Furthermore, the current article explicitly offers comprehensive details regarding application of NPLS-based nanocarriers encapsulating several drugs intended for the handling of numerous disorders, including diabetes, cancer, HIV, malaria, cardiovascular and respiratory as well as skin diseases.

Novel pH-triggered biocompatible polymeric micelles based on heparin-α-tocopherol conjugate for intracellular delivery of docetaxel in breast cancer

In this study, pH-triggered polymeric micelle comprising α-tocopherol (TOC) and heparin (HEP) was developed and loaded with docetaxel (DTX). The amphiphilic copolymer was synthesized by grafting TOC onto HEP backbone by a pH-cleavable bond. DTX-loaded micelles were characterized in terms of critical micelle concentration (CMC), particle size, zeta potential, entrapment efficiency (EE), pH-responsive behavior, and drug release. In vitro cytotoxicity of the micelles against breast cancer cells was investigated by MTT assay. The cellular uptake of coumarin-loaded micelles was also evaluated. Furthermore, the pharmacokinetics of DTX-loaded micelles was evaluated and compared with that of Taxotere^®.HEP-CA-TOC copolymers showed low CMC values and high EE. At pH 7.4, the micelles remained stable in size and shape, whereas considerable changes in particle size and morphology were observed at pH 5.5. DTX-loaded micelles showed pH-dependent drug release profiles. Coumarin-loaded micelles showed higher cellular uptake than free coumarin. Therefore, the DTX-loaded micelles showed more toxicity against breast cancer cells than free DTX. A significant increase in T_1/2 β, AUC_0-∞ and MRT was observed in DTX-loaded micelle treated group as compared to the group treated with Taxotere^®.The results suggest that the pH-sensitive HEP-modified micelles could be promising for enhanced intracellular drug delivery of DTX for cancer treatment.

Poly(γ-Glutamic Acid)/Chitosan Hydrogel Nanoparticles For Effective Preservation And Delivery Of Fermented Herbal Extract For Enlarging Hair Bulb And Enhancing Hair Growth

Introduction

Hair growth-promoting herbal extract mixtures (4HGF) exhibits significant anti-inflammatory activities relevant to promoting hair growth; however, its efficacy in patients with hair loss has been limited majorly due to its low penetration ability into hair follicles. Herein, we prepared hydrogels via dropwise addition of poly(γ-glutamic acid) (PGA) solution containing 4HGF into chitosan (CS) solution, resulting in quick formation of ~400 nm-sized hydrogel particles through electrostatic interaction-derived ionic gelation with over 50% encapsulation efficiency of 4HGF (PGA-4HGF).

Methods

The size and morphology of PGA-4HGF were characterized by TEM, SEM, and dynamic light scattering analyses. Encapsulation efficiency and loading capacity of 4HGF within PGA-4HGF, as well as in vitro release profiles were determined by simply measuring the characteristic absorbance of 4HGF. Penetrating efficiency of PGA-4HGF was evaluated by tracking the respective fluorescence through model porcine skin with confocal laser microscope system. By treating PGA-4HGF on telogenic mice and dermal papilla cells (DPCs), we evaluated the size of hair bulbs in mice, as well as morphological changes in DPCs.

Results

Negligible and sustained release of entrapped 4HGF from the hydrogel nanoparticles were observed under acidic and physiological pH conditions, respectively, which is quite advantageous to control their release and prolong their hair growth-promoting effect. The hydrogel nanoparticles were penetrable through the porcine skin after incubation with or without shaking. After treating telogenic mice and DPCs with PGA-4HGF, we detected enlargement of hair bulbs and remarkable shape changes, respectively, thereby showing its potential in induction of hair growth.

Conclusion

These results suggest that the hydrogel nanoparticle formulation developed in this study can be employed as a potential approach for the preservation of hair growth-promoting compounds, their delivery of into hair follicles, and enhancing hair growth.

Carbohydrate-based nanocarriers and their application to target macrophages and deliver antimicrobial agents

Many deadly infections are produced by microorganisms capable of sustained survival in macrophages. This reduces exposure to chemadrotherapy, prevents immune detection, and is akin to criminals hiding in police stations. Therefore, the use of glyco-nanoparticles (GNPs) as carriers of therapeutic agents is a burgeoning field. Such an approach can enhance the penetration of drugs into macrophages with specific carbohydrate targeting molecules on the nanocarrier to interact with macrophage lectins. Carbohydrates are natural biological molecules and the key constituents in a large variety of biological events such as cellular communication, infection, inflammation, enzyme trafficking, cellular migration, cancer metastasis and immune functions. The prominent characteristics of carbohydrates including biodegradability, biocompatibility, hydrophilicity and the highly specific interaction of targeting cell-surface receptors support their potential application to drug delivery systems (DDS). This review presents the 21^st century development of carbohydrate-based nanocarriers for drug targeting of therapeutic agents for diseases localized in macrophages. The significance of natural carbohydrate-derived nanoparticles (GNPs) as anti-microbial drug carriers is highlighted in several areas of treatment including tuberculosis, salmonellosis, leishmaniasis, candidiasis, and HIV/AIDS.

Three-dimensional cryogels for biomedical applications

Cryogels are a subset of hydrogels synthesized under sub-zero temperatures: initially solvents undergo active freezing, which causes crystal formation, which is then followed by active melting to create interconnected supermacropores. Cryogels possess several attributes suited for their use as bioscaffolds, including physical resilience, bio-adaptability, and a macroporous architecture. Furthermore, their structure facilitates cellular migration, tissue-ingrowth, and diffusion of solutes, including nano- and micro-particle trafficking, into its supermacropores. Currently, subsets of cryogels made from both natural biopolymers such as gelatin, collagen, laminin, chitosan, silk fibroin, and agarose and/or synthetic biopolymers such as hydroxyethyl methacrylate, poly-vinyl alcohol, and poly(ethylene glycol) have been employed as 3D bioscaffolds. These cryogels have been used for different applications such as cartilage, bone, muscle, nerve, cardiovascular, and lung regeneration. Cryogels have also been used in wound healing, stem cell therapy, and diabetes cellular therapy. In this review, we summarize the synthesis protocol and properties of cryogels, evaluation techniques as well as current in vitro and in vivo cryogel applications. A discussion of the potential benefit of cryogels for future research and their application are also presented.

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.

Production of LMWH-conjugated core/shell hydrogels encapsulating paclitaxel for transdermal delivery: In vitro and in vivo assessment

Topical applications that reduce systemic toxic effects while increasing therapeutic efficacy are a promising alternative strategy. The aim of this study was to provide an enhanced transdermal delivery of low molecular weight heparin (LMWH) through the stratum corneum by using cationic carrier as a novel permeation enhancer. Recent studies have shown that heparin-conjugated biomaterials can be effective in inhibiting tumor growth during cancer treatment due to their high ability to bind growth factors. Paclitaxel (PCL) was co-encapsulated into the same cationic carrier for the purpose of improving of therapeutic efficacy for a combined cancer treatment with LMWH. In vitro and in vivo studies showed that the LMWH and PCL release was significantly affected by polymer molecular weight and block composition. Skin penetration tests have indicated that larger amounts of LMWH were absorbed from LMWH-gel conjugate through SC, than aqueous formula. However, it was found that the plasma transition of LMWH released from gel conjugate was lower compared to the plasma concentration of LMWH released from aqueous solution. It is recommended that PCL-loaded LMWH-conjugated core/shell hydrogels can be used as promising drug release systems for transdermal applications that can improve therapeutic efficacy and reduce side effects in a combined cancer treatment.

Heparin Functionalized Injectable Cryogel with Rapid Shape-Recovery Property for Neovascularization

Cryogel based scaffolds have high porosity with interconnected macropores that may provide cell compatible microenvironment. In addition, cryogel based scaffolds can be utilized in minimally invasive surgery due to its sponge-like properties, including rapid shape recovery and injectability. Herein, we developed an injectable cryogel by conjugating heparin to gelatin as a carrier for vascular endothelial growth factor (VEGF) and fibroblasts in hindlimb ischemic disease. Our gelatin/heparin cryogel showed gelatin concentration-dependent mechanical properties, swelling ratios, interconnected porosities, and elasticities. In addition, controlled release of VEGF led to effective angiogenic responses both in vitro and in vivo. Furthermore, its sponge-like properties enabled cryogels to be applied as an injectable carrier system for in vivo cells and growth factor delivery. Our heparin functionalized injectable cryogel facilitated the angiogenic potential by facilitating neovascularization in a hindlimb ischemia model.

bFGF plays a neuroprotective role by suppressing excessive autophagy and apoptosis after transient global cerebral ischemia in rats

Transient global cerebral ischemia (tGCI) is a cerebrovascular disorder that can cause apoptotic neuronal damage and functional deficits. Basic fibroblast growth factor (bFGF) was reported to be highly expressed in the central nervous system (CNS) and to exert neuroprotective effects against different CNS diseases. However, the effects of bFGF on tGCI have not been studied intensively. This study was conducted to investigate the effect of bFGF and its underlying mechanism in an animal model of tGCI. After intracerebroventricular (i.c.v.) injection of bFGF, functional improvement was observed, and the number of viable neurons increased in the ischemia-vulnerable hippocampal CA1 region. Apoptosis was induced after tGCI and could be attenuated by bFGF treatment via inhibition of p53 mitochondrial translocation. In addition, autophagy was activated during this process, and bFGF could inhibit activation of autophagy through the mTOR pathway. Rapamycin, an activator of autophagy, was utilized to explore the relationship among bFGF, apoptosis, and autophagy. Apoptosis deteriorated after rapamycin treatment, which indicated that excessive autophagy could contribute to the apoptosis process. In conclusion, these results demonstrate that bFGF could exert neuroprotective effects in the hippocampal CA1 region by suppressing excessive autophagy via the mTOR pathway and inhibiting apoptosis by preventing p53 mitochondrial translocation. Furthermore, our results suggest that bFGF may be a promising therapeutic agent to for treating tGCI in response to major adverse events, including cardiac arrest, shock, extracorporeal circulation, traumatic hemorrhage, and asphyxiation.

Single dose HBsAg CS-γ-PGA nanogels induce potent protective immune responses against HBV infection

Hepatitis B virus (HBV) infection is a severe threat to public health, which can be prevented by prophylactic vaccination. Here, we tested nanogels carriers in the prophylactic effect of hepatitis B surface antigen (HBsAg) vaccine. HBsAg nanogels (Ng) were prepared using chitosan (CS) and poly-γ-glutamic acid (γ-PGA). Positively charged Ng (+) and negatively charged Ng (-) were prepared by adjusting the CS and γ-PGA proportion. Dendritic cells (DCs) maturation in mice immunized with HBsAg Ng (+) and HBsAg Ng (-) could be augmented in response to pAAV/HBV1.2 plasmid challenge. Single-dose immunization with HBsAg Ng (+) induced HBsAg specific-antibodies. HBsAg Ng (+) immunized mice cleared HBsAg and restored anti-HBs production after pAAV/HBV1.2 plasmid challenge. Single-dose HBsAg Ng (+) induced humoral and cellular immunity, and could induce effector memory T cells. Single-dose HBsAg Ng (-) favored the induction of cellular immunity, and induced central memory T cells and effector memory T cells. However, HBsAg elimination was similar between HBsAg Ng (+)- and HBsAg Ng (+) plus HBsAg Ng (-)-immunized mice. Zeta potential measurements showed that HBsAg Ng (+) were more stable than HBsAg Ng (-). Therefore, Ng (+) are desirable HBsAg prophylactic vaccine carriers, providing long-term protection against HBV, and are a good choice to study and apply weakly immunostimulatory antigens.

Passive targeting and lung tolerability of enoxaparin microspheres for a sustained antithrombotic activity in rats

Pulmonary bed can retain microparticles (MP) larger than their capillaries' diameter, hence we offer a promising way for lung passive targeting following intravenous (IV) administration. In this study, enoxaparin (Enox)-albumin microspheres (Enox-Alb MS) were, optimally, developed as lung targeted sustained release MP for IV use. Lung tolerability and targeting efficiency of Enox-Alb MS were tested, and the pharmacokinetic profile following IV administration to albino rats was constructed. In vivo studies confirmed high lung targeting efficiency of Enox-Alb MS with lack of potential tissue toxicity. The anticoagulant activity of the selected Alb MS was significantly sustained for up to 38 h compared to 5 h for the market product. Alb MS are promising delivery carriers for controlled and targeted delivery of Enox to the lungs for prophylaxis and treatment of pulmonary embolism.

The Synthesis and Structural Characterization of Graft Copolymers Composed of γ-PGA Backbone and Oligoesters Pendant Chains

The novel copolymers composed of poly-γ-glutamic acid (γ-PGA) and oligoesters have been developed. The structures of the obtained copolymers including variety of end groups were determined at the molecular level with the aid of electrospray ionization multistage mass spectrometry (ESI-MSⁿ). The fragmentation experiment performed for the selected sodium adducts of the copolymers confirmed that the developed methods lead to the formation of graft copolymers composed of poly-γ-glutamic acid (γ-PGA) backbone and oligoesters pendant chains. Moreover, it was established that fragmentation of selected sodium adducts of graft copolymers proceeded via random breakage of amide bonds along the backbone and ester bonds of the oligoesters pendant chains. Considering potential applications of the synthesized copolymers in the area of biomaterials, the hydrolytic degradation under laboratory conditions and in vitro cytotoxicity tests were performed. The ESI-MSⁿ technique applied in this study has been proven to be a useful tool in structural studies of novel graft copolymers as well as their degradation products. Graphical Abstract ᅟ.

In vivo evaluation of cetuximab-conjugated poly(γ-glutamic acid)-docetaxel nanomedicines in EGFR-overexpressing gastric cancer xenografts

Epidermal growth factor receptor (EGFR), upregulated in gastric cancer patients, is an oncogene of interest in the development of targeted cancer nanomedicines. This study demonstrates in silico modeling of monoclonal antibody cetuximab (CET MAb)-conjugated docetaxel (DOCT)-loaded poly(γ-glutamic acid) (γ-PGA) nanoparticles (Nps) and evaluates the in vitro/in vivo effects on EGFR-overexpressing gastric cancer cells (MKN-28). Nontargeted DOCT-γ-PGA Nps (NT Nps: 110±40 nm) and targeted CET MAb-DOCT-γ-PGA Nps (T Nps: 200±20 nm) were prepared using ionic gelation followed by 1-Ethyl-3-(3-dimethyl aminopropyl)carbodiimide–N-Hydoxysuccinimide (EDC–NSH) chemistry. Increased uptake correlated with enhanced cytotoxicity induced by targeted Nps to EGFR +ve MKN-28 compared with nontargeted Nps as evident from MTT and flow cytometric assays. Nanoformulated DOCT showed a superior pharmacokinetic profile to that of free DOCT in Swiss albino mice, indicating the possibility of improved therapeutic effect in the disease model. Qualitative in vivo imaging showed early and enhanced tumor targeted accumulation of CET MAb-DOCT-γ-PGA Nps in EGFR +ve MKN-28–based gastric cancer xenograft, which exhibited efficient arrest of tumor growth compared with nontargeted Nps and free DOCT. Thus, actively targeted CET MAb-DOCT-γ-PGA Nps could be developed as a substitute to conventional nonspecific chemotherapy, and hence could become a feasible strategy for cancer therapy for EGFR-overexpressing gastric tumors.

Bacterial-Derived Polymer Poly-y-Glutamic Acid (y-PGA)-Based Micro/Nanoparticles as a Delivery System for Antimicrobials and Other Biomedical Applications

In the past decade, poly-γ-glutamic acid (γ-PGA)-based micro/nanoparticles have garnered remarkable attention as antimicrobial agents and for drug delivery, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. γ-PGA is a naturally occurring biopolymer produced by several gram-positive bacteria that, due to its biodegradable, non-toxic and non-immunogenic properties, has been used successfully in the medical, food and wastewater industries. Moreover, its carboxylic group on the side chains can offer an attachment point to conjugate antimicrobial and various therapeutic agents, or to chemically modify the solubility of the biopolymer. The unique characteristics of γ-PGA have a promising future for medical and pharmaceutical applications. In the present review, the structure, properties and micro/nanoparticle preparation methods of γ-PGA and its derivatives are covered. Also, we have highlighted the impact of micro/nanoencapsulation or immobilisation of antimicrobial agents and various disease-related drugs on biodegradable γ-PGA micro/nanoparticles.

Poly(γ-glutamic acid) and poly(γ-glutamic acid)-based nanocomplexes enhance type II collagen production in intervertebral disc

Intervertebral disc (IVD) degeneration often leads to low back pain, which is one of the major causes of disability worldwide, affecting more than 80% of the population. Although available treatments for degenerated IVD decrease symptoms' progression, they fail to address the underlying causes and to restore native IVD properties. Poly(γ-glutamic acid) (γ-PGA) has recently been shown to support the production of chondrogenic matrix by mesenchymal stem/stromal cells. γ-PGA/chitosan (Ch) nanocomplexes (NCs) have been proposed for several biomedical applications, showing advantages compared with either polymer alone. Hence, this study explores the potential of γ-PGA and γ-PGA/Ch NCs for IVD regeneration. Nucleotomised bovine IVDs were cultured ex vivo upon injection of γ-PGA (pH 7.4) and γ-PGA/Ch NCs (pH 5.0 and pH 7.4). Tissue metabolic activity and nucleus pulposus DNA content were significantly reduced when NCs were injected in acidic-buffered solution (pH 5.0). However, at pH 7.4, both γ-PGA and NCs promoted sulphated glycosaminoglycan production and significant type II collagen synthesis, as determined at the protein level. This study is a first proof of concept that γ-PGA and γ-PGA/Ch NCs promote recovery of IVD native matrix, opening new perspectives on the development of alternative therapeutic approaches for IVD degeneration.

Co-Assembly of Heparin and Polypeptide Hybrid Nanoparticles for Biomimetic Delivery and Anti-Thrombus Therapy

Biomimetic delivery carriers using polypeptide/heparin hybrid nanoparticles that are adsorbed onto red blood cells for extended blood circulation time have been developed. This might open up an avenue to promote the innovations and advances of biomimetic, stimuli-responsive drug delivery, especially for the site-specific treatment of intravascular diseases such as thrombosis.

Synthesis and Structural Characterization of Bioactive PHA and γ-PGA Oligomers for Potential Applications as a Delivery System

The (trans)esterification reaction of bacterial biopolymers with a selected bioactive compound with a hydroxyl group was applied as a convenient method for obtaining conjugates of such compound. Tyrosol, a naturally occurring phenolic compound, was selected as a model of a bioactive compound with a hydroxyl group. Selected biodegradable polyester and polyamide, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) and poly-γ-glutamic acid (γ-PGA), respectively, were used. The (trans)esterification reactions were carried out in melt mediated by 4-toluenesulfonic acid monohydrate. The structures of (trans)esterification products were established at the molecular level with the aid of ESI-MS² (electrospray ionization tandem mass spectrometry) and/or ¹H NMR (nuclear magnetic resonance) techniques. Performed analyses confirmed that the developed method leads to the formation of conjugates in which bioactive compounds are covalently bonded to biopolymer chains. The amount of covalently bonded bioactive compounds in the resulting conjugates depends on the type of biopolymers applied in synthesis.

Suppression of Hepatic Inflammation via Systemic siRNA Delivery by Membrane-Disruptive and Endosomolytic Helical Polypeptide Hybrid Nanoparticles

Treatment of inflammatory diseases represents one of the biggest clinical challenges. RNA interference (RNAi) against TNF-α provides a promising modality toward anti-inflammation therapy, but its therapeutic potential is greatly hampered by the by the lack of efficient siRNA delivery vehicles in vivo. Herein, we report a hybrid nanoparticulate (HNP) system based on a cationic helical polypeptide PPABLG for the efficient delivery of TNF-α siRNA. The helical structure of PPABLG features pore formation on cellular and endosomal membranes to facilitate the direct translocation as well as endosomal escape of TNF-α siRNA in macrophages, representing a unique superiority to a majority of the existing polycation-based gene vectors that experience severe endosomal entrapment and lysosomal degradation. As such, HNPs containing TNF-α siRNA afforded effective systemic TNF-α knockdown following systemic administration at a low dose of 50 μg of siRNA/kg and thus demonstrated a potent anti-inflammatory effect to rescue animals from LPS/d-GalN-induced hepatic sepsis. This study therefore verifies that the bioactive secondary structure of polypeptides significantly dominates the in vivo siRNA delivery efficiency, and the unique properties of PPABLG HNPs render remarkable potentials for anti-inflammation therapies.