Multilayered materials based on biopolymers as drug delivery systems

Trilayered nanocellulose-based patches loaded with acyclovir and hyaluronic acid for the treatment of herpetic lesions

This study focuses on the preparation of layered bacterial nanocellulose (BNC) patches for drug delivery and wound healing in the context of herpes labialis. Nanostructured patches were prepared by selective aqueous diffusion of acyclovir (ACV, antiviral drug), hyaluronic acid (HA, skin healing promoter), and glycerol (GLY, plasticizer and humectant) in the BNC network, followed by assembly into trilayered patches with ACV on the central layer of the patch (ACVT) or divided between two layers (ACVH), to modulate drug release. Both patches showed good layers' adhesion and thermal stability (125 °C), UV barrier properties, good static (Young's modulus up to 0.9 GPa (dry) and 0.7 GPa (wet)) and dynamic mechanical performance, and adhesion strength (21 kPa) comparable to or higher than other materials and commercial adhesives for wound healing. In vitro drug dissolution showed faster ACV release from the ACVH patch (77 ± 5 %, 10 min) than from the ACVT one (50 ± 7 %), suggesting efficient drug delivery. ACVH closely resembled a commercial cream formulation in terms of release and permeation profiles. The patches were non-cytotoxic toward L929 fibroblasts, promoting cell adhesion and wound closure (in vitro). These results underscore the dual-action potential of the layered patches for managing herpetic lesions.

Design and In Vitro Activity of Furcellaran/Chitosan Multilayer Microcapsules for the Delivery of Glutathione and Empty Model Multilayer Microcapsules Based on Polysaccharides

In this study, multilayer microcapsules (two-layer and four-layer) based on furcellaran (FUR) and chitosan (CHIT) were produced, enclosing a tripeptide with an antioxidant effect-glutathione-in different concentrations. In addition, for the first time, an empty, four-layer microcapsule based on CHIT and FUR (ECAPS) was obtained, which can be used to contain sensitive, active substances of a hydrophobic nature. Layering was monitored using zeta potential, and the presence of the resulting capsules was confirmed by SEM imaging. In the current study, we also investigated whether the studied capsules had any effect on the Hep G2 cancer cell line. An attempt was also made to identify the possible molecular mechanism(s) by which the examined capsules suppressed the growth of Hep G2 cells. In this report, we demonstrate that the capsules suppressed the growth of cancer cells. This mechanism was linked to the modulation of the AKT/PI3K signaling pathway and the induction of the G2/M arrest cell cycle. Furthermore, the results indicate that the tested multilayer microcapsules induced cell death through an apoptotic pathway.

Co-encapsulation and release of apigenin and ascorbic acid in polyelectrolyte multilayer capsules for targeted polycystic ovary syndrome

Polycystic ovary syndrome (PCOS), a prevalent endocrine disorder in women of reproductive age, is linked to hormonal imbalances and oxidative stress. Our study investigates the regenerative potential of apigenin (AP, hydrophobic) and ascorbic acid (AC, hydrophilic) encapsulated within poly (allylamine hydrochloride) and dextran sulfate (PAH/DS) hollow microcapsules for PCOS. These microcapsules, constructed using a layer-by-layer (LbL) assembly, are found to be 4 ± 0.5 μm in size. Our research successfully demonstrates the co-encapsulation of AP and AC in a single PAH/DS system with high encapsulation efficiency followed by successful release at physiological conditions by CLSM investigations. In vitro tests with testosterone-treated CHO cells reveal that the dual-drug-loaded PAH/DS capsules effectively reduce intracellular ROS levels and apoptosis and offering protection. In an in-vivo zebrafish model, these capsules demonstrate active biodistribution to targeted ovaries and reduce testosterone levels through radical scavenging. Histopathological examinations show that the injected dual-drug-loaded PAH/DS microcapsules assist in the development of ovarian follicles in testosterone-treated zebrafish. Hence, this dual-drug-loaded system, capable of co-encapsulating two natural compounds, effectively interacts with ovarian cells, reducing cellular damage and normalizing PCOS conditions.

A comprehensive review on nanocomposite biomaterials based on gelatin for bone tissue engineering

The creation of a suitable scaffold is a crucial step in the process of bone tissue engineering (BTE). The scaffold, acting as an artificial extracellular matrix, plays a significant role in determining the fate of cells by affecting their proliferation and differentiation in BTE. Therefore, careful consideration should be given to the fabrication approach and materials used for scaffold preparation. Natural polypeptides such as gelatin and collagen have been widely used for this purpose. The unique properties of nanoparticles, which vary depending on their size, charge, and physicochemical properties, have demonstrated potential in solving various challenges encountered in BTE. Therefore, nanocomposite biomaterials consisting of polymers and nanoparticles have been extensively used for BTE. Gelatin has also been utilized in combination with other nanomaterials to apply for this purpose. Composites of gelatin with various types of nanoparticles are particularly promising for creating scaffolds with superior biological and physicochemical properties. This review explores the use of nanocomposite biomaterials based on gelatin and various types of nanoparticles together for applications in bone tissue engineering.

The effect of silicon groups on the physicochemical property and bioactivity of L-phenylalanine derived poly(amide-imide)

Poly(amide-imide) (PAI), serving as a synthetic polymer, has been widely used in industry for excellent mechanical properties, chemical resistance and high thermal stability. However, lack of suitable cell niche and biological activity limited the further application of PAI in biomedical engineering. Herein, silicon modified L-phenylalanine derived poly(amide-imide) (PAIS) was synthesized by introducing silica to L-phenylalanine derived PAI to improve physicochemical and biological performances. The influence of silicon amount on physicochemical, immune, and angiogenic performances of PAIS were systemically studied. The results show that PAIS exerts excellent hydrophilic, mechanical, biological activity. PAIS shows no effects on the number of macrophages, but can regulate macrophage polarization and angiogenesis in a dose-dependent manner. This study advanced our understanding of silicon modification in PAI can modulate cell responses via initiating silicon concentration regulation. The acquired knowledge will provide a new strategy to design and optimize biomedical PAI in the future.

Localized, on-demand, sustained drug delivery from biopolymer-based materials

INTRODUCTION

Local drug delivery facilitiates higher concentrations of drug molecules at or near the treatment site to enhance treatment efficiency and reduce drug toxicity and other systemic side effects. However, local drug delivery systems face challenges in terms of encapsulation, delivery, and controlled release of therapeutics.

AREAS COVERED

We provide an overview of naturally derived biopolymer-based drug delivery systems for localized, sustained, and on-demand treatment. We introduce the advantages and limitations of these systems for drug encapsulation, delivery, and local release, as well as recent applications.

EXPERT OPINION

Naturally derived biopolymers like cellulose, silk fibroin, chitosan, alginate, hyaluronic acid, and gelatin are good candidates for localized drug delivery because they are readily chemically modified, biocompatible, biodegradable (with the generation of metabolically compatible degradation products), and can be processed in aqueous and ambient environments to maintain the bioactivity of various therapeutics. The tradeoff between the effective treatment dosage and the response by local healthy tissue should be balanced during the design of these delivery systems. Future directions will be focused on strategies to design tunable and controlled biodegradation rates, as well as to explore commercial utility in substituting biopolymer-based systems for currently utilized synthetic polymers for implants for drug delivery.

Advanced Nanocellulose-Based Materials: Production, Properties, and Applications

Natural polymers, such as polysaccharides and proteins, are being extensively utilized as substrates to create advanced materials [...].

Natural Polymers-Based Materials: A Contribution to a Greener Future

Natural polymers have emerged as promising candidates for the sustainable development of materials in areas ranging from food packaging and biomedicine to energy storage and electronics. In tandem, there is a growing interest in the design of advanced materials devised from naturally abundant and renewable feedstocks, in alignment with the principles of Green Chemistry and the 2030 Agenda for Sustainable Development. This review aims to highlight some examples of the research efforts conducted at the Research Team BioPol4fun, Innovation in BioPolymer-based Functional Materials and Bioactive Compounds, from the Portuguese Associate Laboratory CICECO–Aveiro Institute of Materials at the University of Aveiro, regarding the exploitation of natural polymers (and derivatives thereof) for the development of distinct sustainable biobased materials. In particular, focus will be given to the use of polysaccharides (cellulose, chitosan, pullulan, hyaluronic acid, fucoidan, alginate, and agar) and proteins (lysozyme and gelatin) for the assembly of composites, coatings, films, membranes, patches, nanosystems, and microneedles using environmentally friendly strategies, and to address their main domains of application.

Spherical Cellulose Micro and Nanoparticles: A Review of Recent Developments and Applications

Cellulose, the most abundant natural polymer, is a versatile polysaccharide that is being exploited to manufacture innovative blends, composites, and hybrid materials in the form of membranes, films, coatings, hydrogels, and foams, as well as particles at the micro and nano scales. The application fields of cellulose micro and nanoparticles run the gamut from medicine, biology, and environment to electronics and energy. In fact, the number of studies dealing with sphere-shaped micro and nanoparticles based exclusively on cellulose (or its derivatives) or cellulose in combination with other molecules and macromolecules has been steadily increasing in the last five years. Hence, there is a clear need for an up-to-date narrative that gathers the latest advances on this research topic. So, the aim of this review is to portray some of the most recent and relevant developments on the use of cellulose to produce spherical micro- and nano-sized particles. An attempt was made to illustrate the present state of affairs in terms of the go-to strategies (e.g., emulsification processes, nanoprecipitation, microfluidics, and other assembly approaches) for the generation of sphere-shaped particles of cellulose and derivatives thereof. A concise description of the application fields of these cellulose-based spherical micro and nanoparticles is also presented.

Cellulose Nanocrystals/Chitosan-Based Nanosystems: Synthesis, Characterization, and Cellular Uptake on Breast Cancer Cells

Cellulose nanocrystals (CNCs) are elongated biobased nanostructures with unique characteristics that can be explored as nanosystems in cancer treatment. Herein, the synthesis, characterization, and cellular uptake on folate receptor (FR)-positive breast cancer cells of nanosystems based on CNCs and a chitosan (CS) derivative are investigated. The physical adsorption of the CS derivative, containing a targeting ligand (folic acid, FA) and an imaging agent (fluorescein isothiocyanate, FITC), on the surface of the CNCs was studied as an eco-friendly methodology to functionalize CNCs. The fluorescent CNCs/FA-CS-FITC nanosystems with a rod-like morphology showed good stability in simulated physiological and non-physiological conditions and non-cytotoxicity towards MDA-MB-231 breast cancer cells. These functionalized CNCs presented a concentration-dependent cellular internalization with a 5-fold increase in the fluorescence intensity for the nanosystem with the higher FA content. Furthermore, the exometabolic profile of the MDA-MB-231 cells exposed to the CNCs/FA-CS-FITC nanosystems disclosed a moderate impact on the cells’ metabolic activity, limited to decreased choline uptake and increased acetate release, which implies an anti-proliferative effect. The overall results demonstrate that the CNCs/FA-CS-FITC nanosystems, prepared by an eco-friendly approach, have a high affinity towards FR-positive cancer cells and thus might be applied as nanocarriers with imaging properties for active targeted therapy.

On the Development of All-Cellulose Capsules by Vesicle-Templated Layer-by-Layer Assembly

Polymeric multilayer capsules formed by the Layer-by-Layer (LbL) technique are interesting candidates for the purposes of storage, encapsulation, and release of drugs and biomolecules for pharmaceutical and biomedical applications. In the current study, cellulose-based core-shell particles were developed via the LbL technique alternating two cellulose derivatives, anionic carboxymethylcellulose (CMC), and cationic quaternized hydroxyethylcellulose ethoxylate (QHECE), onto a cationic vesicular template made of didodecyldimethylammonium bromide (DDAB). The obtained capsules were characterized by dynamic light scattering (DLS), ζ potential measurements, and high-resolution scanning electron microscopy (HR-SEM). DLS measurements reveal that the size of the particles can be tuned from a hundred nanometers with a low polydispersity index (deposition of 2 layers) up to micrometer scale (deposition of 6 layers). Upon the deposition of each cellulose derivative, the particle charge is reversed, and pH is observed to considerably affect the process thus demonstrating the electrostatic driving force for LbL deposition. The HR-SEM characterization suggests that the shape of the core-shell particles formed is reminiscent of the spherical vesicle template. The development of biobased nano- and micro-containers by the alternating deposition of oppositely charged cellulose derivatives onto a vesicle template offers several advantages, such as simplicity, reproducibility, biocompatibility, low-cost, mild reaction conditions, and high controllability over particle size and composition of the shell.

Antibacterial Multi-Layered Nanocellulose-Based Patches Loaded with Dexpanthenol for Wound Healing Applications

Antibacterial multi-layered patches composed of an oxidized bacterial cellulose (OBC) membrane loaded with dexpanthenol (DEX) and coated with several chitosan (CH) and alginate (ALG) layers were fabricated by spin-assisted layer-by-layer (LbL) assembly. Four patches with a distinct number of layers (5, 11, 17, and 21) were prepared. These nanostructured multi-layered patches reveal a thermal stability up to 200 °C, high mechanical performance (Young's modulus ≥ 4 GPa), and good moisture-uptake capacity (240-250%). Moreover, they inhibited the growth of the skin pathogen Staphylococcus aureus (3.2-log CFU mL-1 reduction) and were non-cytotoxic to human keratinocytes (HaCaT cells). The in vitro release profile of DEX was prolonged with the increasing number of layers, and the time-dependent data imply a diffusion/swelling-controlled drug release mechanism. In addition, the in vitro wound healing assay demonstrated a good cell migration capacity, headed to a complete gap closure after 24 h. These results certify the potential of these multi-layered polysaccharides-based patches toward their application in wound healing.

Biomedical Applications of Multifunctional Polymeric Nanocarriers: A Review of Current Literature

Polymeric nanomaterials have become a prominent area of research in the field of drug delivery. Their application in nanomedicine can improve bioavailability, pharmacokinetics, and, therefore, the effectiveness of various therapeutics or contrast agents. There are many studies for developing new polymeric nanocarriers; however, their clinical application is somewhat limited. In this review, we present new complex and multifunctional polymeric nanocarriers as promising and innovative diagnostic or therapeutic systems. Their multifunctionality, resulting from the unique chemical and biological properties of the polymers used, ensures better delivery, and a controlled, sequential release of many different therapeutics to the diseased tissue. We present a brief introduction of the classical formulation techniques and describe examples of multifunctional nanocarriers, whose biological assessment has been carried out at least in vitro. Most of them, however, also underwent evaluation in vivo on animal models. Selected polymeric nanocarriers were grouped depending on their medical application: anti-cancer drug nanocarriers, nanomaterials delivering compounds for cancer immunotherapy or regenerative medicine, components of vaccines nanomaterials used for topical application, and lifestyle diseases, ie, diabetes.

Inter-protein interactions govern protein loading into porous vaterite CaCO3 crystals

Loading of therapeutic proteins into mesoporous vaterite crystals is driven by inter-protein interactions in bulk solution and inside the crystals.

Fabricating β-cyclodextrin based pH-responsive nanotheranostics as a programmable polymeric nanocapsule for simultaneous diagnosis and therapy

Background

Fabrication of a smart drug delivery system that could dramatically increase the efficiency of chemotherapeutic drugs and reduce the side effects is still a challenge for pharmaceutical researchers. By the emergence of nanotechnology, a huge window was opened towards this goal, and a wide type of nanocarriers were introduced for delivering the chemotherapeutic to the cancer cells, among them are cyclodextrins with the ability to host different types of hydrophobic bioactive molecules through inclusion complexation process.

Aim

The aim of this study is to design and fabricate a pH-responsive theranostic nanocapsule based on cyclodextrin supramolecular nano-structure.

Materials and methods

This nanostructure contains iron oxide nanoparticles in the core surrounded with three polymeric layers including polymeric β-cyclodextrin, polyacrylic acid conjugated to sulfadiazine, and polyethylenimine functionalized with β-cyclodextrin. Sulfadiazine is a pH-responsive hydrophobic component capable of making inclusion complex with β-cyclodextrin available in the first and third layers. Doxorubicin, as an anti-cancer drug model, was chosen and the drug loading and release pattern were determined at normal and acidic pH. Moreover, the biocompatibility of the nanocapsule (with/without drug component) was examined using different techniques such as MTT assay, complement activation, coagulation assay, and hemolysis.

Results

The results revealed the successful preparation of a spherical nanocapsule with mean size 43±1.5 nm and negatively charge of −43 mV that show 160% loading efficacy. Moreover, the nanocapsule has an on/off switching release pattern in response to pH that leads to drug released in low acidic pH. The results of the biocompatibility tests indicated that this nano drug delivery system had no effect on blood and immune components while it could affect cancer cells even at very low concentrations (0.3 μg mL⁻¹).

Conclusion

The obtained results suggest that this is a “switchable” theranostic nanocapsule with potential application as an ideal delivery system for simultaneous cancer diagnosis and therapy.

Preparation of Nafion/Polycation Layer-by-Layer Films for Adsorption and Release of Insulin

Thin films were prepared using layer-by-layer (LbL) deposition of Nafion (NAF) and polycations such as poly(allylamine hydrochloride) (PAH), poly(ethyleneimine) (PEI), and poly(diallydimethylammonium chloride) (PDDA). Insulin was then adsorbed on the NAF-polycation LbL films by immersion in an insulin solution. The NAF-polycation LbL films were characterized using a quartz crystal microbalance and an atomic force microscope. The release of insulin from the LbL films was characterized using UV-visible adsorption spectroscopy and fluorescence emission spectroscopy. The greatest amount of insulin was adsorbed on the NAF-PAH LbL film. The amount of insulin adsorbed on the (NAF/PAH)₅NAF LbL films by immersion in a 1 mg mL-1 insulin solution at pH 7.4 was 61.8 µg cm-2. The amount of insulin released from the LbL films was higher when immersed in insulin solutions at pH 2.0 and pH 9.0 than at pH 7.4. Therefore, NAF-polycations could be employed as insulin delivery LbL films under mild conditions and as an insulin release control system according to pH change.

Protein-Polymer Microcapsules for PCR Technology

Protein-polymer microcapsules have attracted much attention, due to their special features and potential in biological use. How to make the most of this type of bio-abiotic hybrid material is an intriguing question. Nevertheless, several unsatisfactory technical issues significantly limited the application of these materials. For instance, introducing various biomolecules and crosslinking for the capsules remains challenging and problematic. In this report, recombinant mCherry protein was covalently linked with poly(N-isopropylacrylamide) (PNIPAAm) to form amphiphilic protein-polymer conjugates, which assembled into microcapsules. These microcapsules are thermoresistant and can be used in the polymerase chain reaction (PCR). In this setting, the reactant molecules can be readily and easily introduced into the microcapsules, and crosslinking and water-oil phase transition are not necessary. This protein-polymer microcapsule PCR system has potential in various biological applications.

Distribution of PEG-coated hollow polyelectrolyte microcapsules after introduction into the circulatory system and muscles of zebrafish

The use of polyelectrolyte multilayer microcapsules as carriers for fluorescent molecular probes is a prospective technique for monitoring the physiological characteristics of animal vasculature and interstitial environment in vivo Polyelectrolyte microcapsules have many features that favor their use as implantable carriers of optical sensors, but little information is available on their interactions with complex living tissues, distribution or residence time following different routes of administration in the body of vertebrates. Using the common fish model, the zebrafish Danio rerio, we studied in vivo the distribution of non-biodegradable microcapsules covered with polyethylene glycol (PEG) over time in the adults and evaluated potential side effects of their delivery into the fish bloodstream and muscles. Fluorescent microcapsules administered into the bloodstream and interstitially (in concentrations that were sufficient for visualization and spectral signal recording) both showed negligible acute toxicity to the fishes during three weeks of observation. The distribution pattern of microcapsules delivered into the bloodstream was stable for at least one week, with microcapsules prevalent in capillaries-rich organs. However, after intramuscular injection, the phagocytosis of the microcapsules by immune cells was manifested, indicating considerable immunogenicity of the microcapsules despite PEG coverage. The long-term negative effects of chronic inflammation were also investigated in fish muscles by histological analysis.

Poly(N-methacryloyl glycine)/nanocellulose composites as pH-sensitive systems for controlled release of diclofenac

The present study reports the development of non-cytotoxic and pH-sensitive nanostructured membranes consisting of a polymer with amino acid pending moieties and bacterial nanocellulose (BC). The nanocomposites were prepared through a simple methodology under green reaction conditions. The obtained materials display good thermal stability (up to 200°C), viscoelastic (storage modulus>700MPa) and mechanical (Young's modulus=3.5-4.9GPa) properties, together with high water uptake capacity. The results of the in vitro MTT assay showed that the nanocomposites are non-cytotoxic to HaCaT cells for 72h. The in vitro release profile of diclofenac sodium salt (DCF) from the nanocomposites into simulated body fluids at different pH values demonstrates the pH-responsive behaviour of these materials. Besides, DCF is mainly retained in the nanocomposites at pH 2.1 and released at pH 7.4, revealing their potential for the controlled release of DCF in dermal as well as in oral drug delivery applications.