Controlled released of drug from doubled-walled PVA hydrogel/PCL microspheres prepared by single needle electrospraying method

Synthesis of a PVA-GO drug delivery system for sustained release of 4-methyl umbelliferon

INTRODUCTION

4-methyl umbelliferon (4MU) is a coumarin with anti-inflammatory, anti-thrombotic, enzyme-inhibiting, and antioxidant properties. Despite the benefits of the compound, it is eliminated very quickly from the blood circulation through the liver, kidney, and digestive system due to its hydrophobic properties. In this study we proposed to improve the durability of 4MU by binding of 4MU to poly vinyl alcohol (PVA) and graphene oxide (GO).

METHODS

The PVA-4MU-GO complex was synthesized and characterized. Release of 4MU from the complex was investigated. H9C2 cells viability was investigated and the entry of complex to the cell was analyzed using flow cytometry.

RESULT

UV-Vis and FTIR studies confirmed the interaction of 4MU with PVA and GO. SEM measurement also revealed a particle size around 101 nm for PVA-4MU-GO complexes. The obtained results confirmed the assembly of PVA-4MU-GO. A continuous drug release for 8 d (160 h) was achieved. Cytotoxic studies on H9C2 cell showed that PVA-4MU-GO complex is dependent to the concentration of GO and also the relation of 4MU to GO. Sustained release and penetration of PVA-4MU-GO complex into the H9C2 cell were observed.

CONCLUSION

PVA-4MU-GO complex is recommended as an alternative for 4MU. Synthesis the complex of PVA-4MU-GO, verifying the correct binding, showing the in vitro release of the 4MU, as well as checking its toxicity and its gradual entry into the H9C2 cell, were performed in this study.

Se-incorporated polycaprolactone spherical polyhedron enhanced vitamin B2 loading and prolonged release for potential application in proliferative skin disorders

Development of novel drug vehicles for vitamin B2 (VitB2) delivery is very important for designing controllable release system to improve epidermal growth and bone metabolism. In this work, selenium (Se)-incorporated polycaprolactone (PCL) spherical polyhedrons are successfully synthesized via a single emulsion solvent evaporation method which is utilized to load VitB2 to fabricate cell-responsive Se-PCL@VitB2 delivery systems. Their physicochemical properties are characterized by DLS, SEM, XRD, FTIR, and TGA-DSC. The release kinetics of VitB2 or Se from the samples are investigated in PBS solution (pH = 2.0, 5.0, 7.4, 8.0 and 12.0). The cytocompatibilities are also evaluated with normal BMSC and epidermal HaCat cells. Results exhibit that Se-PCL@VitB2 particles presents spherical polyhedral morphology (approximately (3.25 ± 0.46) μm), negative surface charge (-(54.03 ± 2.94) mV), reduced crystallinity and good degradability. Stability experiments imply that both VitB2 and Se might be uniformly dispersed in PCL matrix. And the incorporation of Se facilely promotes the loading of VitB2. The encapsulation efficiency and loading capacity are (98.42 ± 1.06)% and (76.25 ± 1.27) for Se-PCL@VitB2 sample. Importantly, it exhibits more prolonged release of both VitB2 and Se in neutral PBS solution (pH = 7.4) than other pH conditions. Presumably, the electrostatic interaction between Se, VitB2 and PCL contribute to its release mode. Cell experiments show that Se-PCL@VitB2 presents strong cytotoxicity to HaCat cells mainly due to the cytotoxic effect of Se anions and PCL degradation products. However, it exhibits weak inhibitory effect on BMSC cells. These note that the synthesized Se-PCL@VitB2 particles can be promising drug vehicles for potential application in epidermal proliferative disorders.

Electrospray Nano-Micro Composite Sodium Alginate Microspheres with Shape-Adaptive, Antibacterial, and Angiogenic Abilities for Infected Wound Healing

Nonhealing infectious wounds, characterized by bacterial colonization, wound microenvironment destruction, and shape complexity, present an intractable problem in clinical practice. Inspired by LEGOs, building-block toys that can be assembled into desired shapes, we proposed the use of electrospray nano-micro composite sodium alginate (SA) microspheres with antibacterial and angiogenic properties to fill irregularly shaped wounds instantly. Specifically, porous poly(lactic-co-glycolic acid) (PLGA) microspheres (MSs) encapsulating basic fibroblast growth factor (bFGF) were produced by a water-in-oil-in-water double-emulsion method. Then, bFGF@MSs were blended with the SA solution containing ZIF-8 nanoparticles. The resultant solution was electrosprayed to obtain nano-micro composite microspheres (bFGF@MS/ZIF-8@SAMSs). The composite MSs' size could be regulated by PLGA MS mass proportion and electrospray voltage. Moreover, bFGF, a potent angiogenic agent, and ZIF-8, bactericidal nanoparticles, were found to release from bFGF@MS/ZIF-8@SAMSs in a controlled and sustainable manner, which promoted cell proliferation, migration, and tube formation and killed bacteria. Through experimentation on rat models, bFGF@MS/ZIF-8@SAMSs were revealed to adapt to wound shapes and accelerate infected wound healing because of the synergistic effects of antibacterial and angiogenic abilities. In summation, this study developed a feasible approach to prepare bioactive nano-micro MSs as building blocks that can fill irregularly shaped infected wounds and improve healing.

Molecular Engineering of Electrosprayed Hydrogel Microspheres to Achieve Synergistic Anti-Tumor Chemo-Immunotherapy with ACEA Cargo

Molecular engineering of drug delivering platforms to provide collaborative biological effects with loaded drugs is of great medical significance. Herein, cannabinoid receptor 1 (CB1)- and reactive oxygen species (ROS)-targeting electrosprayed microspheres (MSs) are fabricated by loading with the CB1 agonist arachidonoyl 2'-chloroethylamide (ACEA) and producing ROS in a photoresponsive manner. The synergistic anti-tumor effects of ACEA and ROS released from the MSs are assessed. ACEA inhibits epidermal growth factor receptor signaling and altered tumor microenvironment (TME) by activating CB1 to induce tumor cell death. The MSs are composed of glycidyl methacrylate-conjugated xanthan gum (XGMA) and Fe3+, which form dual molecular networks based on a Fe3+-(COO-)3 network and a C═C addition reaction network. Interestingly, the Fe3+-(COO-)3 network can be disassembled instantly under the conditions of lactate sodium and ultraviolet exposure, and the disassembly is accompanied by massive ROS production, which directly injures tumor cells. Meanwhile, the transition of dual networks to a single network boosts the ACEA release. Together, the activities of the ACEA and MSs promote immunogenic tumor cell death and create a tumor-suppressive TME by increasing M1-like tumor-associated macrophages and CD8+ T cells. In summation, this study demonstrates strong prospects of improving anti-tumor effects of drug delivering platforms through molecular design.

Precision targeting in hepatocellular carcinoma: Exploring ligand-receptor mediated nanotherapy

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and poses a major challenge to global health due to its high morbidity and mortality. Conventional chemotherapy is usually targeted to patients with intermediate to advanced stages, but it is often ineffective and suffers from problems such as multidrug resistance, rapid drug clearance, nonspecific targeting, high side effects, and low drug accumulation in tumor cells. In response to these limitations, recent advances in nanoparticle-mediated targeted drug delivery technologies have emerged as breakthrough approaches for the treatment of HCC. This review focuses on recent advances in nanoparticle-based targeted drug delivery systems, with special attention to various receptors overexpressed on HCC cells. These receptors are key to enhancing the specificity and efficacy of nanoparticle delivery and represent a new paradigm for actively targeting and combating HCC. We comprehensively summarize the current understanding of these receptors, their role in nanoparticle targeting, and the impact of such targeted therapies on HCC. By gaining a deeper understanding of the receptor-mediated mechanisms of these innovative therapies, more effective and precise treatment of HCC can be achieved.

Electrospun Nanofibers Encapsulated with Natural Products: A Novel Strategy to Counteract Skin Aging

The skin is the primary tissue affected by wounds and aging, significantly impacting its protective function. Natural products are widely used in cosmetics, representing a new approach to preventing age-related damage. Nanomedicine combines nanotechnology and traditional treatments to create innovative drugs. The main targets of nanotechnological approaches are wound healing, regeneration, and rejuvenation of skin tissue. The skin barrier is not easily permeable, and the creation of modern nanodevices is a way to improve the passive penetration of substances. In this study, Helichrysum italicum oil (HO) was combined with different types of electrospun nanofibers to study their protective activity on the skin and to evaluate their future application for topical treatments. In the present research, we used biodegradable polymers, including polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), which were characterized by a scanning electron microscope (SEM). All results show a positive trend in cell proliferation and viability of human skin stem cells (SSCs) and BJ fibroblasts pre-treated with combined nanofibers and then exposed to UV stress. Gene expression analysis revealed the activation of a molecular rejuvenation program in SSCs treated with functionalized nanofibers before UV exposure. Understanding the mechanisms involved in skin changes during aging allows for the future application of nanomaterials combined with HO directly to the patients.

Controlled and customizable baculovirus NOS3 gene delivery using PVA-based hydrogel systems

Nitric oxide synthase 3 (NOS3) eluting polyvinyl alcohol-based hydrogels have a large potential in medical applications and device coatings. NOS3 promotes nitric oxide and nitrate production and can effectively be delivered using insect cell viruses, termed baculoviruses. Nitric oxide is known for regulating cell proliferation, promoting blood vessel vasodilation, and inhibiting bacterial growth. The polyvinyl alcohol (PVA)-based hydrogels investigated here sustained baculovirus elution from five to 25 days, depending on the hydrogel composition. The quantity of viable baculovirus loaded significantly declined with each freeze-thaw from one to four (15.3 ± 2.9% vs. 0.9 ± 0.5%, respectively). The addition of gelatin to the hydrogels protected baculovirus viability during the freeze-thaw cycles, resulting in a loading capacity of 94.6 ± 1.2% with sustained elution over 23 days. Adding chitosan, PEG-8000, and gelatin to the hydrogels altered the properties of the hydrogel, including swelling, blood coagulation, and antimicrobial effects, beneficial for different therapeutic applications. Passive absorption of the baculovirus into PVA hydrogels exhibited the highest baculovirus loading (96.4 ± 0.6%) with elution over 25 days. The baculovirus-eluting hydrogels were hemocompatible and non-cytotoxic, with no cell proliferation or viability reduction after incubation. This PVA delivery system provides a method for high loading and sustained release of baculoviruses, sustaining nitric oxide gene delivery. This proof of concept has clinical applications as a medical device or stent coating by delivering therapeutic genes, improving blood compatibility, preventing thrombosis, and preventing infection.

Recent Progress of Droplet Microfluidic Emulsification Based Synthesis of Functional Microparticles

The remarkable control function over the functional material formation process enabled by droplet microfluidic emulsification approaches can lead to the efficient and one-step encapsulation of active substances in microparticles, with the microparticle characteristics well regulated. In comparison to the conventional fabrication methods, droplet microfluidic technology can not only construct microparticles with various shapes, but also provide excellent templates, which enrich and expand the application fields of microparticles. For instance, intersection with disciplines in pharmacy, life sciences, and others, modifying the structure of microspheres and appending functional materials can be completed in the preparation of microparticles. The as-prepared polymer particles have great potential in a wide range of applications for chemical analysis, heavy metal adsorption, and detection. This review systematically introduces the devices and basic principles of particle preparation using droplet microfluidic technology and discusses the research of functional microparticle formation with high monodispersity, involving a plethora of types including spherical, nonspherical, and Janus type, as well as core-shell, hole-shell, and controllable multicompartment particles. Moreover, this review paper also exhibits a critical analysis of the current status and existing challenges, and outlook of the future development in the emerging fields has been discussed.

Chitosan-Based Hydrogel in the Management of Dermal Infections: A Review

The main objective of this review is to provide a comprehensive overview of the current evidence regarding the use of chitosan-based hydrogels to manage skin infections. Chitosan, a naturally occurring polysaccharide derived from chitin, possesses inherent antimicrobial properties, making it a promising candidate for treating various dermal infections. This review follows a systematic approach to analyze relevant studies that have investigated the effectiveness of chitosan-based hydrogels in the context of dermal infections. By examining the available evidence, this review aims to evaluate these hydrogels' overall efficacy, safety, and potential applications for managing dermal infections. This review's primary focus is to gather and analyze data from different recent studies about chitosan-based hydrogels combating dermal infections; this includes assessing their ability to inhibit the growth of microorganisms and reduce infection-related symptoms. Furthermore, this review also considers the safety profile of chitosan-based hydrogels, examining any potential adverse effects associated with their use. This evaluation is crucial to ensure that these hydrogels can be safely utilized in the management of dermal infections without causing harm to patients. The review aims to provide healthcare professionals and researchers with a comprehensive understanding of the current evidence regarding the use of chitosan-based hydrogels for dermal infection management. The findings from this review can contribute to informed decision-making and the development of potential treatment strategies in this field.

Fabrication of biodegradable hollow microsphere composites made of polybutylene adipate co-terephthalate/polyvinylpyrrolidone for drug delivery and sustained release

Sustained drug release has attracted increasing interest in targeted drug therapy. However, existing methods of drug therapy suffer drug action time, large fluctuations in the effective concentration of the drug, and the risk of side effects. Here, a biodegradable composite of polybutylene adipate co-terephthalate/polyvinylpyrrolidone (PBAT/PVP) consisting of electrospun hollow microspheres as sustained-released drug carriers is presented. The as-prepared PBAT/PVP composites show faster degradation rate and drug (Erlotinib) release than that of PBAT. Furthermore, PBAT/PVP composites loaded with Erlotinib provide sustained release effect, thus achieving a better efficacy than that after the direct injection of erlotinib due to the fact that the composites allow a high drug concentration in the tumor for a longer period. Hence, this work provides a potential effective solution for clinical drug therapy and tissue engineering using drug microspheres with a sustained release.

Development and Characterization of Drug Loaded PVA/PCL Fibres for Wound Dressing Applications

Nowadays, synthetic polymers are used in medical applications due to their special biodegradable, biocompatible, hydrophilic, and non-toxic properties. The materials, which can be used for wound dressing fabrication with controlled drug release profile, are the need of the time. The main aim of this study was to develop and characterize polyvinyl alcohol/polycaprolactone (PVA/PCL) fibres containing a model drug. A dope solution comprising PVA/PCL with the drug was extruded into a coagulation bath and became solidified. The developed PVA/PCL fibres were then rinsed and dried. These fibres were tested for Fourier transform infrared spectroscopy, linear density, topographic analysis, tensile properties, liquid absorption, swelling behaviour, degradation, antimicrobial activity, and drug release profile for improved and better healing of the wound. From the results, it was concluded that PVA/PCL fibres containing a model drug can be produced by using the wet spinning technique and have respectable tensile properties; adequate liquid absorption, swelling %, and degradation %; and good antimicrobial activity with the controlled drug release profile of the model drug for wound dressing applications.

Progress in the application of sustained-release drug microspheres in tissue engineering

Sustained-release drug-loaded microspheres provide a long-acting sustained release, with targeted and other effects. There are many types of sustained-release drug microspheres and various preparation methods, and they are easy to operate. For these reasons, they have attracted widespread interest and are widely used in tissue engineering and other fields. In this paper, we provide a systematic review of the application of sustained-release drug microspheres in tissue engineering. First, we introduce this new type of drug delivery system (sustained-release drug carriers), describe the types of sustained-release drug microspheres, and summarize the characteristics of different microspheres. Second, we summarize the preparation methods of sustained-release drug microspheres and summarize the materials required for preparing microspheres. Third, various applications of sustained-release drug microspheres in tissue engineering are summarized. Finally, we summarize the shortcomings and discuss future prospects in the development of sustained-release drug microspheres. The purpose of this paper was to provide a further systematic understanding of the application of sustained-release drug microspheres in tissue engineering for the personnel engaged in related fields and to provide inspiration and new ideas for studies in related fields.

Application of single and cooperative different delivery systems for the treatment of intervertebral disc degeneration

Intervertebral disc (IVD) degeneration (IDD) is the most universal pathogenesis of low back pain (LBP), a prevalent and costly medical problem across the world. Persistent low back pain can seriously affect a patient's quality of life and even lead to disability. Furthermore, the corresponding medical expenses create a serious economic burden to both individuals and society. Intervertebral disc degeneration is commonly thought to be related to age, injury, obesity, genetic susceptibility, and other risk factors. Nonetheless, its specific pathological process has not been completely elucidated; the current mainstream view considers that this condition arises from the interaction of multiple mechanisms. With the development of medical concepts and technology, clinicians and scientists tend to intervene in the early or middle stages of intervertebral disc degeneration to avoid further aggravation. However, with the aid of modern delivery systems, it is now possible to intervene in the process of intervertebral disc at the cellular and molecular levels. This review aims to provide an overview of the main mechanisms associated with intervertebral disc degeneration and the delivery systems that can help us to improve the efficacy of intervertebral disc degeneration treatment.

Fabrication and investigating in vivo wound healing property of coconut oil loaded nanofiber/hydrogel hybrid scaffold

Obtaining a sustainable drug delivery system is a challenging issue in biomedical science. This became even more important in the wound regeneration process due to its long treatment process. In this study, the calcium alginate (CaAlg) hydrogel is coated on the surface of polycaprolactone (PCL)/gelatin (Gel) nanofibers containing coconut oil (CO) using the impregnation method. The physical, chemical, and morphological properties of produced samples are investigated using different characterization techniques to verify the influence of hydrogel. Water contact angle, swelling ratio, and water vapor permeability measurements are used to evaluate the effect of hydrogel on the hydrophilicity of the proposed system. The cell viability test showed that the nanocomposite hydrogel is biocompatible and could improve wound healing. According to drug release studies, hydrogel addition to the nanofiber system plays an essential role in controlling CO release rate in the first 250 h. In vivo studies also indicated faster skin regeneration.

Dual-Functional Nanofibrous Patches for Accelerating Wound Healing

Bacterial infections and inflammation are two main factors for delayed wound healing. Coaxial electrospinning nanofibrous patches, by co-loading and sequential co-delivering of anti-bacterial and anti-inflammation agents, are promising wound dressing for accelerating wound healing. Herein, curcumin (Cur) was loaded into the polycaprolactone (PCL) core, and broad-spectrum antibacterial tetracycline hydrochloride (TH) was loaded into gelatin (GEL) shell to prepare PCL-Cur/GEL-TH core-shell nanofiber membranes. The fibers showed a clear co-axial structure and good water absorption capacity, hydrophilicity and mechanical properties. In vitro drug release results showed sequential release of Cur and TH, in which the coaxial mat showed good antioxidant activity by DPPH test and excellent antibacterial activity was demonstrated by a disk diffusion method. The coaxial mats showed superior biocompatibility toward human immortalized keratinocytes. This study indicates a coaxial nanofiber membrane combining anti-bacterial and anti-inflammation agents has great potential as a wound dressing for promoting wound repair.

Oral delivery of curcumin via multi-bioresponsive polyvinyl alcohol and guar gum based double-membrane microgels for ulcerative colitis therapy

Anti-inflammatory drugs for ulcerative colitis (UC) treatment should specifically penetrate and accumulate in the colon tissue. Herein, a multi-bioresponsive anti-inflammatory drug (curcumin, CUR)-loaded heterogeneous double-membrane microgels (CUR@microgels) for oral administration was fabricated in this study, in which the inner core was derived from polyvinyl alcohol (PVA) and guar gum (GG) and the outer gel was decoration with alginate and chitosan by polyelectrolyte interactions. The structure and morphology of microgels were characterized. In vitro, the formulation exhibited good bio-responses at different pH conditions and sustained-release properties in simulated colon fluid with a drug-release rate of 84.6 % over 34 h. With the assistance of the outlayer gels, the microgels effectively delayed the premature drug release of CUR in the upper gastrointestinal tract. In vivo studies revealed that CUR@microgels specifically accumulated in the colon tissue for 24 h, which suggest that the interlayer gels were apt to reach colon lesion. As expected, the oral administration of microgels remarkably alleviated the symptoms of UC and protected the colon tissue in DSS-induced UC mice. The above results indicated that these facilely fabricated microgels which exhibited excellent biocompatibility and multi-bioresponsive drug release, had an apparent effect on the treatment of UC, which represents a promising drug delivery strategy for CUR in a clinical application.

Glass Transition Temperature of PLGA Particles and the Influence on Drug Delivery Applications

Over recent decades, poly(lactic-co-glycolic acid) (PLGA) based nano- and micro- drug delivery vehicles have been rapidly developed since PLGA was approved by the Food and Drug Administration (FDA). Common factors that influence PLGA particle properties have been extensively studied by researchers, such as particle size, polydispersity index (PDI), surface morphology, zeta potential, and drug loading efficiency. These properties have all been found to be key factors for determining the drug release kinetics of the drug delivery particles. For drug delivery applications the drug release behavior is a critical property, and PLGA drug delivery systems are still plagued with the issue of burst release when a large portion of the drug is suddenly released from the particle rather than the controlled release the particles are designed for. Other properties of the particles can play a role in the drug release behavior, such as the glass transition temperature (T_g). The T_g, however, is an underreported property of current PLGA based drug delivery systems. This review summarizes the basic knowledge of the glass transition temperature in PLGA particles, the factors that influence the T_g, the effect of T_g on drug release behavior, and presents the recent awareness of the influence of T_g on drug delivery applications.

Physically crosslinked PVA/graphene-based materials/aloe vera hydrogel with antibacterial activity

Burn is a major skin injury that occurs worldwide. For second-degree burns, special treatment should be given for creating a suitable wound healing environment. Hydrogel wound dressing as the primary care should possess extra properties that include antibacterial activity and cytocompatibility to enhance the treatment effectiveness. Additional therapy such as electrical stimulation can be applied as well promote wound healing. Herein, we used the tissue engineering concept to create a novel antibacterial and cytocompatible hydrogel made of polyvinyl alcohol (PVA), graphene-based material (GBM), and aloe vera extract (Av) through the freeze-thaw process. We prepared the PVA/GBM/Av hydrogel and examined its potential as a wound dressing. We found that it exhibited excellent hydrophilicity with a contact angle between 15 and 31 degrees and electrical conductivity within the range of 0.0102-0.0154 S m-1, which is comparable to that of the human skin tissue and possesses tensile strength up to 1.5 MPa with elongation of 405%. It also demonstrated good stability in phosphate buffer saline with a weight ratio of 73-80% after 14 days of immersion. We presented that the addition of graphene and graphene oxide (GO) inhibited the growth of Gram-positive Staphylococcus aureus ATCC 6538 with the lowest bacterial population observed in PVA/GO, which is 1.74 × 107 cfu mL-1 after 1 day incubation and 99.94% bacterial reduction. Furthermore, our PVA/GBM/Av showed no toxicity to 3T3 fibroblast cells after 48 h with viability up to 295% for PVA/GO/Av. In summary, our fabricated hydrogels have shown their potential as wound dressing with antibacterial and non-cytotoxic properties.

PLGA-based biodegradable microspheres in drug delivery: recent advances in research and application

Biodegradable microspheres have been widely used in the field of medicine due to their ability to deliver drug molecules of various properties through multiple pathways and their advantages of low dose and low side effects. Poly (lactic-co-glycolic acid) copolymer (PLGA) is one of the most widely used biodegradable material currently and has good biocompatibility. In application, PLGA with a specific monomer ratio (lactic acid and glycolic acid) can be selected according to the properties of drug molecules and the requirements of the drug release rate. PLGA-based biodegradable microspheres have been studied in the field of drug delivery, including the delivery of various anticancer drugs, protein or peptide drugs, bacterial or viral DNA, etc. This review describes the basic knowledge and current situation of PLGA biodegradable microspheres and discusses the selection of PLGA polymer materials. Then, the preparation methods of PLGA microspheres are introduced, including emulsification, microfluidic technology, electrospray, and spray drying. Finally, this review summarizes the application of PLGA microspheres in drug delivery and the treatment of pulmonary and ocular-related diseases.

Micellar Carriers Based on Amphiphilic PEG/PCL Graft Copolymers for Delivery of Active Substances

Amphiphilic copolymers of alkyne functionalized 2-hydroxyethyl methacrylate (AlHEMA) and poly(ethylene glycol) methyl ether methacrylate (MPEGMA) with graft or V-shaped graft topologies were synthesized. The functionalization of poly(ε-caprolactone) (PCL) with azide group enabled attachment to P(AlHEMA-co-MPEGMA) copolymers via a "click" alkyne-azide reaction. The introduction of PCL as a second side chain type in addition to PEG resulted in heterografted copolymers with modified properties such as biodegradability. "Click" reactions were carried out with efficiencies between 17-70% or 32-50% (for lower molecular weight PCL, 4000 g/mol, or higher molecular weight PCL, 9000 g/mol, respectively) depending on the PEG grafting density. The graft copolymers were self-assembled into micellar superstructures with the ability to encapsulate active substances, such as vitamin C (VitC), arbutin (ARB) or 4-n-butylresorcinol (4nBRE). Drug loading contents (DLC) were obtained in the range of 5-55% (VitC), 39-91% (ARB) and 42-98% (4nBRE). In vitro studies carried out in a phosphate buffer saline (PBS) solution (at pH 7.4 or 5.5) gave the maximum release levels of active substances after 10-240 min depending on the polymer system. Permeation tests in Franz chambers indicated that the bioactive substances after release by micellar systems penetrated through the artificial skin membrane in small amounts, and a majority of the bioactive substances remained inside the membrane, which is satisfactory for most cosmetic applications.

A novel approach to production of Chlorella protothecoides oil-loaded nanoparticles via electrospraying method: Modeling of critical parameters for particle sizing

Bioactive compounds in algae have chain rings that protect the tissue from chemical damage and disease symptoms. In addition, algal bioactive agents have the ability to stimulate the immune system, protective and therapeutic effects against many diseases, including various types of cancers, coronary heart disease, premature aging, and arthritis. These bioactive compounds also have antioxidant, anticoagulant, antiviral, and anti-inflammatory properties. It is very important to encapsulate these algal compounds for preserving bioactive properties. Two of the most efficient methods used for encapsulation are electrospraying and microemulsion techniques. Although electrospraying is a novel technique to produce nanoparticles in recent years, microemulsion is more conventional method compared with electrospraying. In this study, Chlorella protothecoides oil was encapsulated by using sodium alginate and chitosan biopolymers, and the effects of production parameters of electrospraying and microemulsion methods on the particle size and loading efficiency were investigated. Statistical modeling of critical parameters for particle sizing in microemulsion method and electrospraying technique, which is a novel approach to obtain microalgal oil-loaded nanoparticles, was also presented. It was seen that electrospraying is suitable for obtaining smaller nanoparticles (123.9-610 nm), homogeneous distribution, and higher oil loading efficiency (60%-77%) compared with microemulsion method (756.9-1128.2 nm and 57%-73%).