Deformable liposomes for skin therapy with human epidermal growth factor: The effect of liposomal surface charge

Narrative review on nanoparticles based on current evidence: therapeutic agents for diabetic foot infection

Diabetes's effects on wound healing present a major treatment challenge and increase the risk of amputation. When traditional therapies fail, new approaches must be investigated. With their submicron size and improved cellular internalisation, nanoparticles present a viable way to improve diabetic wound healing. They are attractive options because of their innate antibacterial qualities, biocompatibility, and biodegradability. Nanoparticles loaded with organic or inorganic compounds, or embedded in biomimetic matrices such as hydrogels, chitosan, and hyaluronic acid, exhibit excellent anti-inflammatory, antibacterial, and antioxidant properties. Drug delivery systems (DDSs)-more precisely, nanodrug delivery systems (NDDSs)-use the advantages of nanotechnology to get around some of the drawbacks of traditional DDSs. Recent developments show how expertly designed nanocarriers can carry a variety of chemicals, transforming the treatment of diabetic wounds. Biomaterials that deliver customised medications to the wound microenvironment demonstrate potential. Delivery techniques for nanomedicines become more potent than ever, overcoming conventional constraints. Therapeutics for diabetes-induced non-healing wounds are entering a revolutionary era thanks to precisely calibrated nanocarriers that effectively distribute chemicals. This review highlights the therapeutic potential of nanoparticles and outlines the multifunctional nanoparticles of the future that will be used for complete wound healing in diabetics. The investigation of novel nanodrug delivery systems has the potential to revolutionise diabetic wound therapy and provide hope for more efficient and focused therapeutic approaches.

Microcurrent Cloth-Assisted Transdermal Penetration and Follicular Ducts Escape of Curcumin-Loaded Micelles for Enhanced Wound Healing

Purpose

Larger nanoparticles of bioactive compounds deposit high concentrations in follicular ducts after skin penetration. In this study, we investigated the effects of microcurrent cloth on the skin penetration and translocation of large nanoparticle applied for wound repair applications.

Methods

A self-assembly of curcumin-loaded micelles (CMs) was prepared to improve the water solubility and transdermal efficiency of curcumin. Microcurrent cloth (M) was produced by Zn/Ag electrofabric printing to facilitate iontophoretic transdermal delivery. The transdermal performance of CMs combined with M was evaluated by a transdermal system and confocal microscopy. The CMs/iontophoretic combination effects on nitric oxide (NO) production and inflammatory cytokines were evaluated in Raw 264.7 cells. The wound-healing property of the combined treatment was assessed in a surgically created full-thickness circular wound mouse model.

Results

Energy-dispersive X-ray spectroscopy confirmed the presence of Zn/Ag on the microcurrent cloth. The average potential of M was measured to be +214.6 mV in PBS. Large particle CMs (CM-L) prepared using surfactant/cosurfactant present a particle size of 142.9 nm with a polydispersity index of 0.319. The solubility of curcumin in CM-L was 2143.67 μg/mL, indicating 250-fold higher than native curcumin (8.68 μg/mL). The combined treatment (CM-L+M) demonstrated a significant ability to inhibit NO production and increase IL-6 and IL-10 secretion. Surprisingly, microcurrent application significantly improved 20.01-fold transdermal performance of curcumin in CM-L with an obvious escape of CM-L from follicular ducts to surrounding observed by confocal microscopy. The CM-L+M group also exhibited a better wound-closure rate (77.94% on day 4) and the regenerated collagen intensity was approximately 2.66-fold higher than the control group, with a closure rate greater than 90% on day 8 in vivo.

Conclusion

Microcurrent cloth play as a promising iontophoretic transdermal drug delivery accelerator that enhances skin penetration and assists CMs to escape from follicular ducts for wound repair applications.

Enhanced Transdermal Peptide-Modified Flexible Liposomes for Efficient Percutaneous Delivery of Chrysomycin A to Treat Subcutaneous Melanoma and Intradermal MRSA Infection

Superficial skin diseases, including skin infections and tumors, are common healthcare burdens. In this study, the in vivo activity of chrysomycin A (CA) is explored, and a transdermal liposomal CA formulation is further constructed for the simultaneous treatment of cutaneous melanoma and cutaneous methicillin-resistant Staphylococcus aureus (MRSA) infection. The prepared liposomes (TD-LP-CA) display a strong antitumor effect with an IC50 value of less than 0.1 µm in B16-F10 cells, suppress the proliferation of MRSA with a minimum inhibitory concentration (MIC) of 1 µm, and eradicate established MRSA biofilms at 10× MIC in vitro. More importantly, TD-LP-CA shows enhanced stratum corneum (SC) penetration, reaching more than 500 µm beneath the skin's surface due to modification with the TD peptide, and demonstrates excellent subcutaneous tumor penetration after skin application in vivo. TD-LP-CA displays an excellent therapeutic effect against intradermal MRSA infection in mice after topical dermal administration, as well as a moderate inhibitory effect on subcutaneous melanoma with a 75% tumor inhibition rate. The liposomes prepared herein can be a promising carrier for transcutaneous CA transfer for the treatment of superficial diseases such as skin tumors and infections due to their ability to overcome the skin barrier.

Design and Evaluation of Liposomal Sulforaphane-Loaded Polyvinyl Alcohol/Polyethylene Glycol (PVA/PEG) Hydrogels as a Novel Drug Delivery System for Wound Healing

Hydrogel scaffold has been widely applied as drug delivery systems for treating skin injuries. However, the poor drug loading and rapid drug release of hydrogel restricted their application. In the current study, we present a nanoliposome containing sulforaphane (SF) as a nano-drug delivery system that is encapsulated within the scaffold hydrogel system to overcome these limitations and improve wound healing. The hydrogel substrate consisting of 10% polyvinyl alcohol (PVA)/5% polyethylene glycol 400 (PEG400) was prepared by the freeze-thaw method, and the nanoliposomal system was manufactured by the thin film hydration method at different molar ratios of cholesterol: SPC: DPPC: DSPE-PEG2000. The nanoliposome and hydrogel system was characterized by physicochemical analyses. The findings achieved from the optimization of the sulforaphane-loaded nanoliposome (SFNL) displayed an increase in the molar ratio of SPC, leading to a higher entrapment efficiency and a gradual release profile. Narrow size distribution, optimal electrical charge, and the lack of molecular interactions between SF and nanoliposome components in the FTIR analysis make SFNL a suitable drug delivery system for the wound healing process. The obtained SFNL-encapsulated freeze-thawed hydrogel system has sufficient and specific swelling ability at different pH values and increased mechanical strength and elongation. Additionally, the release pattern of SFNL at different pH values showed that the release of SF from liposomes depends on the pH value of the environment and accelerates in line with decreasing pH values. Encapsulation of nanoliposomal SF in the hydrogel structure provides a sustained release pattern of SF compared to its free form and increased as the pH environments continued to raise. The cytotoxicity and cell uptake of SFNL-loaded hydrogels against human skin fibroblasts (HFF cell line) were investigated. The in vitro analyses displayed that the toxicity properties of SF and SFNL were dose-dependent, and SFNL exhibited lower toxicity compared to free SF. Furthermore, the proper cell compatibility of the prepared hydrogel against the HFF cell line was confirmed by the MTT assay. These findings imply that the hydrogel scaffold loaded with SFNL may have wound-healing potential.

Development and evaluation of Resveratrol-loaded liposomes in hydrogel-based wound dressing for diabetic foot ulcer

Diabetic foot wounds (DFUs) are counted as one of the most common microvascular complications associated with poorly controlled and chronic diabetes mellitus. It confers a serious challenge to clinical practice, surmounting hyperglycemia-induced disturbance in angiogenesis and endothelial dysfunction, with limited fruitful intervention to control the manifestations of DFUs. Resveratrol (RV) can improve endothelial function and has strong pro-angiogenic properties for the treatment of diabetic foot wounds. The present study aims to design an RV-loaded liposome-in-hydrogel system to effectively heal diabetic foot ulcers. A thin-film hydration method was used to prepare RV-loaded liposomes. Liposomal vesicles were assessed, for various characteristics such as particle size, zeta potential, and entrapment efficiency. The best-prepared liposomal vesicle was then incorporated into 1% carbopol 940 gel to develop a hydrogel system. The RV-loaded liposomal gel showed improved skin penetration. To assess the efficacy of the developed formulation, a diabetic foot ulcer animal model was used. The topical application of the developed formulation significantly reduced blood glucose and increased glycosaminoglycans (GAGs) to improve ulcer healing as well as wound closure on day 9. Faster re-epithelization, proliferation of fibroblast, formation of collagen, and reduced inflammatory cell infiltration at the wound site were also noted. Results indicate that RV-loaded liposomes in hydrogel-based wound dressing significantly accelerate wound healing in diabetic foot ulcers by restoring the altered wound healing process in diabetics.

A novel deformable liposomal hydrogel loaded with a SREBP-1-inhibiting polypeptide for reducing sebum synthesis in golden hamster model

Excessive sebum is the major factor involved in the pathophysiology of seborrheic diseases. Chemical medicines can result in mild to severe side effects. Polypeptides with much less side effects make them ideal for reducing sebum synthesis. Sterol regulatory element-binding proteins-1 (SREBP-1) is necessary for the biosynthesis of sterols. A SREBP-1-inhibiting polypeptide (SREi), which competitively inhibits the ubiquitination of Insig-1 so as to suppress the activation of SREBP-1 was selected as an active ingredient and formulated into skin topical preparations. The SREi anionic deformable liposomes contained sodium deoxycholate (SDCh) at the concentration of 4.4 mg/mL (SREi-ADL3) and SREi-ADL3 in 0.3% (w/v) carbomer hydrogel (SREi-ADL3-GEL) were prepared and characterized. The SREi-ADL3 presented a high entrapment efficiency of 92.62 ± 6.32%, a particle size of 99.54 ± 7.56 nm and a surface charge of -19.18 ± 0.45 mV. SREi-ADL3-GEL exhibited a sustained release behavior, a higher stability, a much more cellular uptake ability and transdermal absorption. In vivo golden hamster model confirmed that SREi-ADL3-GEL presented the strongest inhibitory effect on sebaceous gland growth and sebum synthesis by down-regulating the mRNA and protein expression of SREBP-1, fatty acid synthase (FAS) and acetyl-coenzyme A carboxylase 1 (ACC1). As confirmed by histological analysis, only a small amount of sebaceous gland lobes with the lightest staining intensity and the smallest dyeing area could be observed in the SREi-ADL3-GEL group. Taken together, SREi-ADL3-GEL displayed potential applications in sebum excessive production related diseases.

EGF, a veteran of wound healing: highlights on its mode of action, clinical applications with focus on wound treatment, and recent drug delivery strategies

Epidermal growth factor (EGF) has been used in wound management and regenerative medicine since the late 1980s. It has been widely utilized for a long time and still is because of its excellent tolerability and efficacy. EGF has many applications in tissue engineering, cancer therapy, lung diseases, gastric ulcers, and wound healing. Nevertheless, its in vivo and during storage stability is a primary concern. This review focuses on the topical use of EGF, especially in chronic wound healing, the emerging use of biomaterials to deliver it, and future research possibilities. To successfully deliver EGF to wounds, a delivery system that is proteolytically resistant and stable over the long term is required. Biomaterials are an area of interest for the development of such systems. These systems may be used in non-healing wounds such as diabetic foot ulcers, pressure ulcers, and burns. In these pathologies, EGF can reduce the risk of amputation of the lower extremities, as it accelerates the wound healing process. Furthermore, appropriate delivery system would also stabilize and control the EGF release profile in a wound. Several in vitro and in vivo studies have already proven the efficacy of such systems in the above-mentioned types of wounds. Moreover, several formulations such as ointments and intralesional injections are already available on the market. However, these products are still problematic in terms of inadequate diffusion of EGF, low bioavailability storage conditions, and shelf-life. This review discusses the nano formulations comprising biomaterials infused with EGF which could be a promising delivery system for chronic wound healing in the future.

Recent Advances in Nano-Drug Delivery Systems for the Treatment of Diabetic Wound Healing

Diabetes mellitus (DM) induced wound healing impairment remains a serious health problem and burden on the clinical obligation for high amputation rates. Based on the features of wound microenvironment, biomaterials loading specific drugs can benefit diabetic wound treatment. Drug delivery systems (DDSs) can carry diverse functional substances to the wound site. Nano-drug delivery systems (NDDSs), benefiting from their features related to nano size, overcome limitations of conventional DDSs application and are considered as a developing process in the wound treatment field. Recently, a number of finely designed nanocarriers efficiently loading various substances (bioactive and non-bioactive factors) have emerged to circumvent constraints faced by traditional DDSs. This review describes various recent advances of nano-drug delivery systems involved in mitigating diabetes mellitus-based non-healing wounds.

Tailored anti-biofilm activity - Liposomal delivery for mimic of small antimicrobial peptide

The eradication of bacteria embedded in biofilms is among the most challenging obstacles in the management of chronic wounds. These biofilms are found in most chronic wounds; moreover, the biofilm-embedded bacteria are considerably less susceptible to conventional antimicrobial treatment than the planktonic bacteria. Antimicrobial peptides and their mimics are considered attractive candidates in the pursuit of novel therapeutic options for the treatment of chronic wounds and general bacterial eradication. However, some limitations linked to these membrane-active antimicrobials are making their clinical use challenging. Novel innovative delivery systems addressing these limitations represent a smart solution. We hypothesized that incorporation of a novel synthetic mimic of an antimicrobial peptide in liposomes could improve its anti-biofilm effect as well as the anti-inflammatory activity. The small synthetic mimic of an antimicrobial peptide, 7e-SMAMP, was incorporated into liposomes (~280 nm) tailored for skin wounds and evaluated for its potential activity against both biofilm formation and eradication of pre-formed biofilms. The 7e-SMAMP-liposomes significantly lowered inflammatory response in murine macrophages (~30 % reduction) without affecting the viability of macrophages or keratinocytes. Importantly, the 7e-SMAMP-liposomes completely eradicated biofilms produced by Staphylococcus aureus and Escherichia coli above concentrations of 6.25 μg/mL, whereas in Pseudomonas aeruginosa the eradication reached 75 % at the same concentration. Incorporation of 7e-SMAMP in liposomes improved both the inhibition of biofilm formation as well as biofilm eradication in vitro, as compared to non-formulated antimicrobial, therefore confirming its potential as a novel therapeutic option for bacteria-infected chronic wounds.

Effect of Chitosan Coating for Efficient Encapsulation and Improved Stability under Loading Preparation and Storage Conditions of Bacillus Lipopeptides

This study aims to evaluate the effect of chitosan coating on the formation and properties of Bacillus cyclic lipopeptide (CLP)-loaded liposomes. A nanoencapsulation strategy for a chitosan-coated liposomal system using lecithin phospholipids for the entrapment of antibiotic CLP prepared from Bacillus subtilis KB21 was developed. The produced chitosan-coated CLP liposome had mean size in the range of 118.47-121.67 nm. Transmission electron microscopy showed the spherical-shaped vesicles. Fourier transform infrared spectroscopy findings indicated the successful coating of the produced CLP-loaded liposomes by the used chitosan. Liposomes coated with 0.2% and 0.5% chitosan concentration decreased the surface tension by 7.3-12.1%, respectively, and increased the CLP content by 15.1-27.0%, respectively, compared to the uncoating liposomes. The coated concentration of chitosan influenced their CLP loading encapsulation efficiency and release kinetics. The physicochemical results of the dynamic light scattering, CLP capture efficiency and long-term storage capacity of nanocapsules increased with chitosan coating concentration. Furthermore, the chitosan-coated liposomes exhibited a significant enhancement in the stability of CLP loading liposomes. These results may suggest the potential application of chitosan-coated liposomes as a carrier of antibiotics in the development of the functional platform.

Enhancing Anticancer Potency of a 13-Substituted Berberine Derivative with Cationic Liposomes

Cationic liposomal formulations of the telomeric G-quadruplex stabilizing ligand, 13-(2-naphthylmethoxy)berberine bromide (1), have been developed with the purpose of delivering 1 into the nucleus of cancer cells for potential telomere targeting. Berberine derivative 1 was encapsulated in various cationic lipids 2-4 by the thin film evaporation method; these lipids are cationic after amine protonation. The most appropriate liposomal berberine formulation was that of 1 and the cholesterol derived cationic lipid 4 in a weight ratio of 1:20 with 76.5% encapsulation efficiency of 1. Cellular uptake studies in the HeLa and HT-29 cancer cells line showed that the liposomal berberine derivative uptake in the cells was higher and more stable than for berberine derivative 1 alone while free 1 was completely decomposed in the cells within 60 min exposure to the cells. Anticancer activity of the liposomal berberine derivative 1 based on 4 was greater than that for the free berberine derivative 1 in the MCF-7, HeLa and HT-29 cell line by 2.3-, 4.9- and 5.3-fold, respectively, and also, interestingly, superior to the anticancer drug doxorubicin against the HT29 cancer cell line.

Anti-inflammatory effects of free and liposome-encapsulated Algerian thermal waters in RAW 264.7 macrophages

The main objectives of this work were to formulate liposomes encapsulating highly mineralized thermal waters (TWs) and to study anti-inflammatory effect of free and encapsulated thermal waters on RAW 264.7 macrophage cells stimulated with lipopolysaccharide (LPS). TWs-loaded conventional and deformable liposomes (TWs-Lip and TWs-DLip) were prepared by sonication and extrusion, respectively. They were considered for their vesicle size, zeta potential, entrapment efficiency, physical stability and in vitro anti-inflammatory effect. Formulated liposome suspensions have a low polydispersity and nanometric size range with zeta potential values close to zero. The vesicle size was stable for 30 days. Entrapment efficiency of TWs was above 90% in conventional liposomes and 70% in deformable liposomes. Pretreatment of LPS-stimulated murine macrophages, with free and liposome-encapsulated TWs, resulted in a significant reduction in nitric oxide (NO) production and modulated tumor necrosis factor-α (TNF-α) production suggesting an anti-inflammatory effect which was even more striking with TWs-Lip and TWs-DLip. Liposome formulations may offer a suitable approach for transdermal delivery of TWs, indicated in inflammatory skin diseases.

Biofilm Responsive Zwitterionic Antimicrobial Nanoparticles to Treat Cutaneous Infection

To avert the poor bioavailability of antibiotics during S. aureus biofilm infections, a series of zwitterionic nanoparticles containing nucleic acid nanostructures were fabricated for the delivery of vancomycin. The nanoparticles were prepared with three main lipids: (i) neutral (soy phosphatidylcholine; P), (ii) positively charged ionizable (1,2-dioleyloxy-3-dimethylaminopropane; D), and (iii) anionic (1,2-dipalmitoyl-sn-glycero-3-phospho((ethyl-1′,2′,3′-triazole) triethylene glycolmannose; M) or (cholesteryl hemisuccinate; C) lipids. The ratio of the anionic lipid was tuned between 0 and 10 mol %, and its impact on surface charge, size, stability, toxicity, and biofilm sensitivity was evaluated. Under biofilm mimicking conditions, the enzyme degradability (via dynamic light scattering (DLS)), antitoxin (via DLS and spectrophotometry), and antibiotic release profile was assessed. Additionally, biofilm penetration, prevention (in vitro), and eradication (ex vivo) of the vancomycin loaded formulation was investigated. Compared with the unmodified nanoparticles which exhibited the smallest size (188 nm), all three surface modified formulations showed significantly larger sizes (i.e., 222–277 nm). Under simulations of biofilm pH conditions, the mannose modified nanoparticle (PDM 90/5/5) displayed ideal charge reversal from a neutral (+1.69 ± 1.83 mV) to a cationic surface potential (+17.18 ± 2.16 mV) to improve bacteria binding and biofilm penetration. In the presence of relevant bacterial enzymes, the carrier rapidly released the DNA nanoparticles to function as an antitoxin against α-hemolysin. Controlled release of vancomycin prevented biofilm attachment and significantly reduced early stage biofilm formations within 24 h. Enhanced biocompatibility and significant ex vivo potency of the PDM 90/5/5 formulation was also observed. Taken together, these results emphasize the benefit of these nanocarriers as potential therapies against biofilm infections and fills the gap for multifunctional nanocarriers that prevent biofilm infections.

Rutin-Loaded Nanovesicles for Improved Stability and Enhanced Topical Efficacy of Natural Compound

Rutin is a natural compound with several pharmacological effects. Among these, antioxidant activity is one of the best known. Despite its numerous benefits, its topical application is severely limited by its physicochemical properties. For this reason, the use of suitable systems could be necessary to improve its delivery through skin, thus enhancing its pharmacological effects. In this regard, the aim of this work is to optimize the ethosomal dispersion modifying both lipid and ethanol concentrations and encapsulating different amounts of rutin. Characterization studies performed on the realized systems highlighted their great stability properties. Studies of encapsulation efficiency and loading degree allowed us to identify a better formulation (EE% 67.5 ± 5.2%, DL% 27 ± 1.7%), which was used for further analyses. The data recorded from in vitro studies showed that the encapsulation into these nanosystems allowed us to overcome the photosensitivity limitation of rutin. Indeed, a markable photostability of the loaded formulation was recorded, compared with that reported from the free rutin solution. The efficacy of the nanosystems was finally evaluated both in vitro on keratinocyte cells and in vivo on human healthy volunteers. The results confirmed the potentiality of rutin-loaded nanosystems for skin disease, mainly related to their anti-inflammatory and antioxidant effects.

Optimization of Nanoparticles for Smart Drug Delivery: A Review

Nanoparticle delivery systems have good application prospects in the treatment of various diseases, especially in cancer treatment. The effect of drug delivery is regulated by the properties of nanoparticles. There have been many studies focusing on optimizing the structure of nanoparticles in recent years, and a series of achievements have been made. This review summarizes the optimization strategies of nanoparticles from three aspects-improving biocompatibility, increasing the targeting efficiency of nanoparticles, and improving the drug loading rate of nanoparticles-aiming to provide some theoretical reference for the subsequent drug delivery of nanoparticles.

Nanotechnology Approaches in Chronic Wound Healing

Significance: The incidence of chronic wounds is increasing due to our aging population and the augment of people afflicted with diabetes. With the extended knowledge on the biological mechanisms underlying these diseases, there is a novel influx of medical technologies into the conventional wound care market. Recent Advances: Several nanotechnologies have been developed demonstrating unique characteristics that address specific problems related to wound repair mechanisms. In this review, we focus on the most recently developed nanotechnology-based therapeutic agents and evaluate the efficacy of each treatment in in vivo diabetic models of chronic wound healing. Critical Issues: Despite the development of potential biomaterials and nanotechnology-based applications for wound healing, this scientific knowledge is not translated into an increase of commercially available wound healing products containing nanomaterials. Future Directions: Further studies are critical to provide insights into how scientific evidences from nanotechnology-based therapies can be applied in the clinical setting.

Characterization of Liposomes Using Quantitative Phase Microscopy (QPM)

The rapid development of nanomedicine and drug delivery systems calls for new and effective characterization techniques that can accurately characterize both the properties and the behavior of nanosystems. Standard methods such as dynamic light scattering (DLS) and fluorescent-based assays present challenges in terms of system's instability, machine sensitivity, and loss of tracking ability, among others. In this study, we explore some of the downsides of batch-mode analyses and fluorescent labeling, while introducing quantitative phase microscopy (QPM) as a label-free complimentary characterization technique. Liposomes were used as a model nanocarrier for their therapeutic relevance and structural versatility. A successful immobilization of liposomes in a non-dried setup allowed for static imaging conditions in an off-axis phase microscope. Image reconstruction was then performed with a phase-shifting algorithm providing high spatial resolution. Our results show the potential of QPM to localize subdiffraction-limited liposomes, estimate their size, and track their integrity over time. Moreover, QPM full-field-of-view images enable the estimation of a single-particle-based size distribution, providing an alternative to the batch mode approach. QPM thus overcomes some of the drawbacks of the conventional methods, serving as a relevant complimentary technique in the characterization of nanosystems.

Preparation and In Vivo Evaluation of Rosmarinic Acid-Loaded Transethosomes After Percutaneous Application on a Psoriasis Animal Model

The topical use of rosmarinic acid (RA) in skin inflammatory pathologies is restricted due to its poor water solubility, poor permeability, and chemical instability. In this study, RA-loaded transethosomes-in-Carbopol® formulations have been developed to evaluate its anti-inflammatory activity on imiquimod-induced psoriasis-like skin inflammation in mice. In vitro release profiles demonstrated sustained behavior due to the retentive action of gel and the entrapment of RA into the vesicles. However, the low viscosity of the combined formulation increased the drug release rate. Animal evaluation of anti-inflammatory activity demonstrated that transethosomes-in-gel containing dexamethasone (Dex-TE-Gel), as positive control, showed effect in all the pro-inflammatory parameters evaluated, evidencing that these drug-loaded nanocarriers have been effectively reached the site of action. In addition, transethosomes-in-gel containing RA (RA-TE-Gel) formulations produced a great reduction in the punch edema (P < 0.001) and in TNF-α and IL-6 (P < 0.05). However, non-significant differences were obtained for IL-1β, IL17, and MPO. Despite the protecting effect of Carbopol® and transethosomes on oxidation index and antioxidant activity of RA over the 7 days of treatment, however, a degradation process of this antioxidant to caffeic acid may be the cause of these in vivo results. We have also checked that the pH existing into the intercellular space of damaged cells (pH 6.8) may be affecting. Therefore, our results suggest that RA-TE-Gel could act as an effective RA formulation for skin delivery; further studies will help to understand the loss of activity at the cellular level.

Challenges and effective routes for formulating and delivery of epidermal growth factors in skin care

Epidermal growth factors are important morphogenetic proteins that instruct cell behaviour. They have many inferred applications within regenerative medicine and have shown promising results in skincare treatments. Many growth factors are known to have skin anti-ageing benefits along with further potential in resolving scarring, acne and other skin disorders. Incorporation of these biologics into skincare formulations has been greatly hindered by low transdermal delivery efficacy, intricate material interactions and protein instability - especially within common cosmetic emulsions. This review explores the cosmeceutical capability of growth factors in skin care, current understandings of constituent interactions and advantageous delivery approaches for more effective topical delivery. The first section highlights the influences growth factor product formulation has on stability and synergy. Current understandings of growth factor formulating techniques in cosmetic products is limited, and the performance of other protein structures is an adequate point of reference. The second section examines emerging drug delivery systems to overcome the challenges of topical growth factor treatment. It is important to consider the coaction and durability of all components in a formulation simultaneously: active ingredients, product format and delivery vehicle, in order to engineer an optimal cosmeceutical product.

Formulation and In Vitro Penetration Study of Recombinant Human Epidermal Growth Factor-Loaded Transfersomal Emulgel

Purpose: Recombinant human epidermal growth factor (rhEGF) is a 6045-Da peptide that promotes the cell growth process, and it is also used for cosmetic purposes as an anti-aging compound. However, its penetration into skin is limited by its large molecular size. This study aimed to prepare rhEGF-loaded transfersomal emulgel with enhanced skin penetration compared with that of non-transfersomal rhEGF emulgel. Methods: Three transfersome formulations were prepared with different ratios between the lipid vesicle (phospholipid and surfactant) and rhEGF (200:1, 133:1, and 100:1) using a thin-film hydration-extrusion method. The physicochemical properties of these transfersomes and the percutaneous delivery of the transfersomal emulgel were evaluated. Long-term and accelerated stability studies were also conducted. Results: The 200:1 ratio of lipid to drug was optimal for rhEGF-loaded transfersomes, which had a particle size of 128.1 ± 0.66 nm, polydispersity index of 0.109 ± 0.004, zeta potential of -43.1 ± 1.07 mV, deformability index of 1.254 ± 0.02, and entrapment efficiency of 97.77% ± 0.09%. Transmission electron microscopy revealed that the transfersomes had spherical and unilamellar vesicles. The skin penetration of rhEGF was enhanced by as much as 5.56 fold by transfersomal emulgel compared with that of non-transfersomal emulgel. The stability study illustrated that the rhEGF levels after 3 months were 84.96-105.73 and 54.45%-66.13% at storage conditions of 2°C-8°C and 25°C ± 2°C/RH 60% ± 5%, respectively. Conclusion: The emulgel preparation containing transfersomes enhanced rhEGF penetration into the skin, and skin penetration was improved by increasing the lipid content.

Human skin models: From healthy to disease-mimetic systems; characteristics and applications

Skin drug delivery is an emerging route in drug development, leading to an urgent need to understand the behaviour of active pharmaceutical ingredients within the skin. Given, As one of the body's first natural defences, the barrier properties of skin provide an obstacle to the successful outcome of any skin drug therapy. To elucidate the mechanisms underlying this barrier, reductionist strategies have designed several models with different levels of complexity, using non-biological and biological components. Besides the detail of information and resemblance to human skin in vivo, offered by each in vitro model, the technical and economic efforts involved must also be considered when selecting the most suitable model. This review provides an outline of the commonly used skin models, including healthy and diseased conditions, in-house developed and commercialized models, their advantages and limitations, and an overview of the new trends in skin-engineered models.

Recent Advancements in Liposome-Targeting Strategies for the Treatment of Gliomas: A Systematic Review

Malignant tumors represent some of the most intractable diseases that endanger human health. A glioma is a tumor of the central nervous system that is characterized by severe invasiveness, blurred boundaries between the tumor and surrounding normal tissue, difficult surgical removal, and high recurrence. Moreover, the blood-brain barrier (BBB) and multidrug resistance (MDR) are important factors that contribute to the lack of efficacy of chemotherapy in treating gliomas. A liposome is a biofilm-like drug delivery system with a unique phospholipid bilayer that exhibits high affinities with human tissues/organs (e.g., BBB). After more than five decades of development, classical and engineered liposomes consist of four distinct generations, each with different characteristics: (i) traditional liposomes, (ii) stealth liposomes, (iii) targeting liposomes, and (iv) biomimetic liposomes, which offer a promising approach to promote drugs across the BBB and to reverse MDR. Here, we review the history, preparatory methods, and physicochemical properties of liposomes. Furthermore, we discuss the mechanisms by which liposomes have assisted in the diagnosis and treatment of gliomas, including drug transport across the BBB, inhibition of efflux transporters, reversal of MDR, and induction of immune responses. Finally, we highlight ongoing and future clinical trials and applications toward further developing and testing the efficacies of liposomes in treating gliomas.

Following the Fate of Dye-Containing Liposomes In Vitro

The rather limited success of translation from basic research to clinical application has been highlighted as a major issue in the nanomedicine field. To identify the factors influencing the applicability of nanosystems as drug carriers and potential nanomedicine, we focused on following their fate through fluorescence-based assays, namely flow cytometry and imaging. These methods are often used to follow the nanocarrier internalization and targeting; however, the validity of the obtained results strictly depends on how much the nanosystem’s fate can be inferred from the fate of fluorescent dyes. To evaluate the parameters that affect the physicochemical and biological stability of the labeled nanosystems, we studied the versatility of two lipid dyes, TopFluor^®-PC and Cy5-DSPE, in conventional liposomes utilizing well-defined in vitro assays. Our results suggest that the dye can affect the major characteristics of the system, such as vesicle size and zeta-potential. However, a nanocarrier can also affect the dye properties. Medium, temperature, time, fluorophore localization and its concentration, as well as their interplay, affect the outcome of tracing experiments. Therefore, an in-depth characterization of the labeled nanosystem should be fundamental to understand the conditions that validate the results within the screening process in optimization of nanocarrier.

Liposomal delivery of antibiotic loaded nucleic acid nanogels with enhanced drug loading and synergistic anti-inflammatory activity against S. aureus intracellular infections

The persistence of Staphylococcus aureus has been accredited to its ability to escape immune response via host cell invasion. Despite the efficacy of many antibiotics against S. aureus, the high extracellular concentrations of conventional antibiotics required for bactericidal activity is limited by their low cellular accumulation and poor intracellular retention. While nanocarriers have received tremendous attention for antibiotic delivery against persistent pathogens, they suffer daunting challenges such as low drug loading, poor retention and untimely release of hydrophilic cargos. Here, a hybrid system (Van_DNL) is fabricated wherein nucleic acid nanogels are caged within a liposomal vesicle for antibiotic delivery. The central principle of this approach relies on exploiting non-covalent electrostatic interactions between cationic cargos and polyanionic DNA to immobilize antibiotics and enable precise temporal release against intracellular S. aureus. In vitro characterization of Van_DNL revealed a stable homogenous formulation with circular morphology and enhanced vancomycin loading efficiency. The hybrid system significantly sustained the release of vancomycin over 24 h compared to liposomal or nanogel controls. Under enzymatic conditions relevant to S. aureus infections, lipase triggered release of vancomycin was observed from the hybrid. While using Van_DNL to treat S. aureus infected macrophages, a dose dependent reduction in intracellular bacterial load was observed over 24 h and exposure to Van_DNL for 48 h caused negligible cellular toxicity. Pre-treatment of macrophages with the antimicrobial hybrid resulted in a strong anti-inflammatory activity in synergy with vancomycin following endotoxin stimulation. Conceptually, these findings highlight these hybrids as a unique and universal platform for synergistic antimicrobial and anti-inflammatory therapy against persistent infections.

A liposome/gelatin methacrylate nanocomposite hydrogel system for delivery of stromal cell-derived factor-1α and stimulation of cell migration

Chronic, non-healing skin and soft tissue wounds are susceptible to infection, difficult to treat clinically, and can severely reduce a patient's quality of life. A key aspect of this issue is the impaired recruitment of mesenchymal stem cells (MSCs), which secrete regenerative cytokines and modulate the phenotypes of other effector cells that promote healing. We have engineered a therapeutic delivery system that can controllably release the pro-healing chemokine stromal cell derived factor-1α (SDF-1α) to induce the migration of MSCs. In order to protect the protein cargo from hydrolytic degradation and control its release, we have loaded SDF-1α in anionic liposomes (lipoSDF) and embedded them in gelatin methacrylate (GelMA) to form a nanocomposite hydrogel. In this study, we quantify the release of SDF-1α from our hydrogel system and measure the induced migration of MSCs in vitro via a transwell assay. Lastly, we evaluate the ability of this system to activate intracellular signaling in MSCs by using Western blots to probe for the phosphorylation of key proteins in the mTOR pathway. To our knowledge, this is the first study to report the delivery of liposomal SDF-1α using a nanocomposite approach. The results of this study expand on our current understanding of factors that can be modified to affect MSC behavior and phenotype. Furthermore, our findings contribute to the development of new hydrogel-based therapeutic delivery strategies for clinical wound healing applications. STATEMENT OF SIGNIFICANCE: Chronic, non-healing wounds promote an inflammatory environment that inhibits the migration of mesenchymal stem cells (MSCs), which secrete pro-healing and regenerative cytokines. The goal of this project is to apply principles of tissue engineering to achieve controllable release of the pro-healing chemokine SDF-1α to modulate the intracellular signaling and migratory behavior of MSCs. In this work, we introduce a nanocomposite strategy to tailor the release of SDF-1α using a liposome/gelatin methacrylate hydrogel approach. We are the first group to report the delivery of liposomal SDF-1α using this strategy. Our findings aim to further elucidate the role of MSCs in directing wound healing and guide the development of immunomodulatory and therapeutic delivery strategies for clinical wound healing applications.

Utilizing Liposomal Quercetin and Gallic Acid in Localized Treatment of Vaginal Candida Infections

Vulvovaginal candidiasis (VVC) is a widely spread fungal infection that causes itching, pain and inflammation at the vaginal site. Although common, currently available treatment suffers from limited efficacy and high recurrence. In addition, the growing problem of resistance to azole drugs used in current treatments emphasizes the need for superior treatment options. Antimicrobial polyphenols are an attractive approach offering multitargeting therapy. We aimed to develop novel liposomes for simultaneous delivery of two polyphenols (quercetin, Q, and gallic acid, GA) that, when released within the vaginal cavity, act in synergy to eradicate infection while alleviating the symptoms of VVC. Q was selected for its anti-itching and anti-inflammatory properties, while GA for its reported activity against Candida. Novel liposomes containing only Q (LP-Q), only GA (LP-GA) or both polyphenols (LP-Q+GA) were in the size range around 200 nm. Q was efficiently entrapped in both LP-Q and in LP-Q+GA (85%) while the entrapment of GA was higher in LP-Q+GA (30%) than in LP-GA (25%). Liposomes, especially LP-Q+GA, promoted sustained release of both polyphenols. Q and GA acted in synergy, increasing the antioxidant activities of a single polyphenol. Polyphenol-liposomes were not cytotoxic and displayed stronger anti-inflammatory effects than free polyphenols. Finally, LP-GA and LP-Q+GA considerably reduced C. albicans growth.