Poly(β,L-malic acid)/Doxorubicin ionic complex: A pH-dependent delivery system

Controlled release of doxorubicin from Poly-(D,L-lactide-co-glycolide) (PLGA) nanoparticles prepared by coaxial electrospraying

Enhancing the efficacy and reducing the toxicity of chemotherapeutic agents like doxorubicin (DOX) is crucial in cancer treatment. Core-shell nanoparticles (NPs) fabricated by coaxial electrospraying offer controlled release of anticancer agents with the polymer shell protecting drug molecules from rapid degradation, prolonging therapeutic effect. This study developed DOX-loaded poly(lactic-co-glycolic acid) (PLGA) NPs. NPs were fabricated with matrix or core-shell structure via single needle or coaxial electrospraying, respectively. Core-shell NPs exhibited high encapsulation efficiency (>80 %) with controlled DOX distribution. Compared to matrix NPs, core-shell NPs demonstrated slower sustained release (69 % in 144 h) after reduced initial burst (22 % in 8 h). Release kinetics followed a diffusion mechanism when compared to free drug and matrix DOX-loaded NPs. In vitro assays showed core-shell NPs' enhanced cytotoxicity against breast cancer cells MCF-7, with higher uptake observed by fluorescence microscopy and flow cytometry. The IC50 for core-shell NPs displayed a significant drop (0.115 μg/mL) compared to matrix NPs (0.235 μg/mL) and free DOX (1.482 μg/mL) after 72 h. Coaxial electrospraying enables the production of therapeutically advantageous core-shell NPs, offering controlled drug release with high encapsulation efficiency, potentially improving clinical anticancer chemotherapy.

Composite Microgels Loaded with Doxorubicin-Conjugated Amine-Functionalized Zinc Ferrite Nanoparticles for Stimuli-Responsive Sustained Drug Release

Purpose

The purpose of this study is to address the need for efficient drug delivery with high drug encapsulation efficiency and sustained drug release. We aim to create nanoparticle-loaded microgels for potential applications in treatment development.

Methods

We adopted the process of ionic gelation to generate microgels from sodium alginate and carboxymethyl cellulose. These microgels were loaded with doxorubicin-conjugated amine-functionalized zinc ferrite nanoparticles (AZnFe-NPs). The systems were characterized using various techniques. Toxicity was evaluated in MCF-7 cells. In vitro release studies were conducted at different pH levels at 37 oC, with the drug release kinetics being analyzed using various models.

Results

The drug encapsulation efficiency of the created carriers was as high as 70%. The nanoparticle-loaded microgels exhibited pH-responsive behavior and sustained drug release. Drug release from them was mediated via a non-Fickian type of diffusion.

Conclusion

Given their high drug encapsulation efficiency, sustained drug release and pH-responsiveness, our nanoparticle-loaded microgels show promise as smart carriers for future treatment applications. Further development and research can significantly benefit the field of drug delivery and treatment development.

Biodegradable Local Chemotherapy Platform with Prolonged and Controlled Release of Doxorubicin for the Prevention of Local Tumor Recurrence

Local recurrence after surgical and therapeutic treatment remains a significant clinical problem in oncology. Recurrence may be due to imperfections in existing therapies, particularly chemotherapy. To improve antitumor activity and prevent local cancer recurrence while keeping toxicity at acceptable levels, we have developed and demonstrated a biodegradable local chemotherapy platform that provides controlled and prolonged drug release. The platform consists of a polycaprolactone (PCL) substrate, which provides the structural integrity of the platform and the predominant unidirectional drug release, and a thin multilayer coating (∼200 nm) containing doxorubicin (DOX). The coating is an electrostatic complex obtained by the layer-by-layer (LbL) assembly and consists of natural polyelectrolytes [poly-γ-glutamic acid (γ-PGA) and chitosan (CS) or poly-l-lysine (PLL)]. To improve the release stability, an ionic conjugate of DOX and γ-PGA was prepared and incorporated into the multilayer coating. By varying the structure of the coating by adding empty (without DOX) bilayers, we were able to control the kinetics of drug release. The resulting platforms contained equal numbers of empty bilayers and DOX-loaded bilayers (15 + 15 or 30 + 30 bilayers) with a maximum loading of 566 ng/cm2. The platforms demonstrated prolonged and fairly uniform drug release for more than 5 months while retaining antitumor activity in vitro on ovarian cancer cells (SKOV-3). The empty platforms (without DOX) showed good cytocompatibility and no cytotoxicity to human fibroblasts and SKOV-3 cells. This study presents the development of a local chemotherapy platform consisting of a PCL-based substrate which provides structural stability and a biodegradable polyelectrolyte layered coating which combines layers containing a polyanion ionic complex with DOX with empty bilayers to ensure prolonged and controlled drug release. Our results may provide a basis for improving the efficacy of chemotherapy using drug delivery systems.

Biosynthesis of poly(β-L-malic acid) from rubberwood enzymatic hydrolysates in co-fermentation by Aureobasidium pullulans

Co-fermentation of multiple substrates has emerged as the most effective method to improve the yield of bioproducts. Herein, sustainable rubberwood enzymatic hydrolysates (RWH) were co-fermented by Aureobasidium pullulans to produce poly(β-L-malic acid) (PMA), and RWH + glucose/xylose was also investigated as co-substrates. Owing to low inhibitor concentration and abundant natural nitrogen source content of RWH, a high PMA yield of 0.45 g/g and a productivity of 0.32 g/L/h were obtained by RWH substrate fermentation. After optimization, PMA yields following the fermentation of RWH + glucose and RWH + xylose reached 59.92 g/L and 53.71 g/L, respectively, which were 52 % and 36 % higher than that after the fermentation of RWH. RWH + glucose more significantly affected the correlation between PMA yield and substrate concentration than RWH + xylose. The results demonstrated that the co-fermentation of RWH co-substrate is a promising method for the synthesis of bioproducts.

Conjugation of folic acid with poly (NVCL-co-PEGMA)-grafted chitosan as a new doxorubicin delivery system

This paper aimed to investigate the synthesis of a novel drug delivery system (DDS) to target tumors and implement the controlled release of doxorubicin (DOX). Chitosan was modified with 3-mercaptopropyltrimethoxysilane and subjected to graft polymerization to implement grafting with the biocompatible thermosensitive copolymer of poly (NVCL-co-PEGMA). A folate receptor-targeting agent was obtained by attaching folic acid. The DDS loading capacity for DOX via physisorption was obtained to be 846.45 mg/g. The synthesized DDS showed temperature- and pH-sensitive drug release behavior in vitro. A temperature of 37 °C and a pH of 7.4 hindered the DOX release, whereas a temperature of 40 °C and a pH of 5.5 led to DOX release acceleration. In addition, the release of DOX was found to occur in a Fickian diffusion mechanism. The MTT assay tests indicated that the synthesized DDS was not detectably toxic to cell lines of breast cancer, while the toxicity of the DOX-loaded DDS was found to be substantial. The cell absorption enhancement of folic acid led to higher cytotoxicity of the DOX-loaded DDS than bare DOX. As a result, the proposed DDS could be a promising alternative for the targeted therapy of breast cancer through controlled drug release.

Clay nanosheets simultaneously intercalated and stabilized by PEGylated chitosan as drug delivery vehicles for cancer chemotherapy

Montmorillonite (MMT) has been frequently utilized as drug vehicles due to its high specific surface area, excellent cation exchange capacity and biocompatibility. However, the significant flocculation of MMT under physiological condition restricted its application to drug delivery. To conquer this problem, the graft-type PEGylated chitosan (PEG-CS) adducts were synthesized as intercalator to stabilize MMT dispersion. Through electrostatic attraction between the chitosan and MMT, the PEG-CS adducts were adsorbed on MMT surfaces and intercalated into MMT. The resulting PEG-CS/MMT nanosheets possessed PEG-rich surfaces, thus showing outstanding dispersion in serum-containing environment. Moreover, the physicochemical characterization revealed that the increased mass ratio of PEG-CS to MMT led to the microstructure transition of PEG-CS/MMT nanosheets from multilayered to exfoliated structure. Interestingly, the PEG-CS/MMT nanosheets with mass ratio of 8.0 in freeze-dried state exhibited a hierarchical lamellar structure organized by the intercalated MMT bundles and unintercalated PEG-CS domains. Notably, the multilayered PEG-CS/MMT nanosheets showed the capability of loading doxorubicin (DOX) superior to the exfoliated counterparts. Importantly, the DOX@PEG-CS/MMT nanosheets endocytosed by TRAMP-C1 cells liberated the drug progressively within acidic organelles, thereby eliciting cell apoptosis. This work provides a new strategy of achieving the controllable dispersion stability of MMT nanoclays towards application potentials in drug delivery.

Polymalic acid for translational nanomedicine

With rich carboxyl groups in the side chain, biodegradable polymalic acid (PMLA) is an ideal delivery platform for multifunctional purposes, including imaging diagnosis and targeting therapy. This polymeric material can be obtained via chemical synthesis, or biological production where L-malic acids are polymerized in the presence of PMLA synthetase inside a variety of microorganisms. Fermentative methods have been employed to produce PMLAs from biological sources, and analytical assessments have been established to characterize this natural biopolymer. Further functionalized, PMLA serves as a versatile carrier of pharmaceutically active molecules at nano scale. In this review, we first delineate biosynthesis of PMLA in different microorganisms and compare with its chemical synthesis. We then introduce the biodegradation mechanism PMLA, its upscaled bioproduction together with characterization. After discussing advantages and disadvantages of PMLA as a suitable delivery carrier, and strategies used to functionalize PMLA for disease diagnosis and therapy, we finally summarize the current challenges in the biomedical applications of PMLA and envisage the future role of PMLA in clinical nanomedicine.

The biosynthesis of polymalic acid (PMLA) and its biotechnical high-grade production from microorganisms compared with the chemical synthesis of PMLA

The physicochemical and biological characteristics of PMLA and its derivatives

How PMLA’s general chemical characteristics can be used to generate various macromolecular compounds for pharmaceutical delivery

The concepts of biological and clinical targeting exemplified by PMLA-based drugs and imaging agents and their biodistribution and biodegradability

An evaluation of the mechanisms that generate preclinical antitumor efficacy and the translational potential for clinical imaging

Sustainable production and biomedical application of polymalic acid from renewable biomass and food processing wastes

Polymalic acid (PMA), a homopolymer of L-malic acid (MA) generated from a yeast-like fungus Aureobasidium pullulans, has unique properties and many applications in food, biomedical, and environmental fields. Acid hydrolysis of PMA, releasing the monomer MA, has become a novel process for the production of bio-based MA, which currently is produced by chemical synthesis using petroleum-derived feedstocks. Recently, current researches attempted to develop economically competitive process for PMA and MA production from renewable biomass feedstocks. Compared to lignocellulosic biomass, PMA and MA production from low-value food processing wastes or by-products, generated from corn, sugarcane, or soybean refinery industries, showed more economical and sustainable for developing a MA derivatives platform from biomass biorefinery to chemical conversion. In the review, we compared the process feasibility for PMA fermentation with lignocellulosic biomass and food process wastes. Some useful strategies for metabolic engineering are summarized. Its changeable applicability and future prospects in food and biomedical fields are also discussed.

Biosynthetic Polymalic Acid as a Delivery Nanoplatform for Translational Cancer Medicine

Poly(β-L-malic acid) (PMLA) is a natural polyester produced by numerous microorganisms. Regarding its biosynthetic machinery, a nonribosomal peptide synthetase (NRPS) is proposed to direct polymerization of L-malic acid in vivo. Chemically versatile and biologically compatible, PMLA can be used as an ideal carrier for several molecules, including nucleotides, proteins, chemotherapeutic drugs, and imaging agents, and can deliver multimodal theranostics through biological barriers such as the blood–brain barrier. We focus on PMLA biosynthesis in microorganisms, summarize the physicochemical and physiochemical characteristics of PMLA as a naturally derived polymeric delivery platform at nanoscale, and highlight the attachment of functional groups to enhance cancer detection and treatment.

Controlled drug delivery for cancer cell treatment via magnetic doxorubicin imprinted silica nanoparticles

Magnetic doxorubicin imprinted silica nanoparticles for remotely triggered doxorubicin release upon applying an alternating magnetic field.

Cockle Shell-Derived Calcium Carbonate (Aragonite) Nanoparticles: A Dynamite to Nanomedicine

Cockle shell is an external covering of small, salt water edible clams (Anadara granosa) that dwells in coastal area. This abundant biomaterial is hard, cheap and readily available with high content of calcium carbonate in aragonite polymorphic form. At present, cockle shell-derived calcium carbonate nanoparticles (CSCaCO3NPs) with dual applications has remarkably drawn significant attention of researchers in nanotechnology as a nanocarrier for delivery of different categories of drugs and as bone scaffold due to its beneficial potentials such as biocompatibility, osteoconductivity, pH sensitivity, slow biodegradation, hydrophilic nature and a wide safety margin. In addition, CSCaCO3NP possesses structural porosity, a large surface area and functional group endings for electrostatic ion bonds with high loading capacity. Thus, it maintains great potential in the drug delivery system and a large number of biomedical utilisations. The pioneering researchers adopted a non-hazardous top-down method for the synthesis of CSCaCO3NP with subsequent improvements that led to the better spherical diameter size obtained recently which is suitable for drug delivery. The method is therefore a simple, low cost and environmentally friendly, which involves little procedural steps without stringent temperature management and expensive hazardous chemicals or any carbonation methods. This paper presents a review on a few different types of nanoparticles with emphasis on the versatile most recent advancements and achievements on the synthesis and developments of CSCaCO3NP aragonite with its applications as a nanocarrier for drug delivery in nanomedicine.

Switching off the interactions between graphene oxide and doxorubicin using vitamin C: combining simplicity and efficiency in drug delivery

Delivery of doxorubicin using graphene oxide is remarkably improved by adding a little amount of vitamin C.

Dynamic contact angle cycling homogenizes heterogeneous surfaces

In order to reduce restenosis, the necessity to develop the appropriate coating material of metallic stent is a challenge for biomedicine and scientific research over the past decade. Therefore, biodegradable copolymers of poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) were prepared in order to develop a new coating exhibiting different custom groups in its side chain and being able to carry a drug. This material will be in direct contact with cells and blood. It consists of carboxylic acid and hexylic groups used for hydrophilic and hydrophobic character, respectively. The study of this material wettability and dynamic surface properties is of importance due to the influence of the chemistry and the potential motility of these chemical groups on cell adhesion and polymer kinetic hydrolysis. Cassie theory was used for the theoretical correction of contact angles of these chemical heterogeneous surfaces coatings. Dynamic Surface Analysis was used as practical homogenizer of chemical heterogeneous surfaces by cycling during many cycles in water. In this work, we confirmed that, unlike receding contact angle, advancing contact angle is influenced by the difference of only 10% of acidic groups (%A) in side-chain of polymers. It linearly decreases with increasing acidity percentage. Hysteresis (H) is also a sensitive parameter which is discussed in this paper. Finally, we conclude that cycling provides real information, thus avoiding theoretical Cassie correction. H(10)is the most sensible parameter to %A.

Ropinirole-dextran sulfate nanoplex for nasal administration against Parkinson's disease: in silico molecular modeling and in vitro-ex vivo evaluation

Dextran sulfate sodium (DS) was allowed to interact ionically with ropinirole hydrochloride (ROPI HCl, an anti-Parkinsonian agent) to synthesize self-assembled ROPI-DS nanoplex. The preliminary objective behind ROPI-DS complexation was to enhance the partitioning of ROPI HCl and thereby its encapsulation into nanocarriers and to improve the nasal membrane permeability. Molecular interactions were computed using in silico molecular modeling. Nanoplex were characterized for physicochemical and partitioning behavior. Optimized ROPI-DS nanoplex was further characterized by spectroscopic and thermal analysis, diffraction studies, morphological and histopathological analysis. In summary, ROPI-DS nanoplex represents a promising nanocarrier material for intranasal administration.

Polyol-based biodegradable polyesters: a short review

Catalyst-free thermal polyesterification has recently emerged as a potential strategy for designing biodegradable thermoset polymers, particularly polyol-based polyesters for biomedical applications. These thermoset polyesters are synthesized through polycondensation of polyol and polyacid without the presence of catalyst or solvents. The mechanical properties, degradation rates, crystallinity, hydrophilicity, and biocompatibility can be controlled by adjusting the monomer feed ratios and curing conditions. These polyesters often degrade via surface erosion that allows the polymers to maintain structural integrity throughout hydrolysis. Additionally, polyol-based polyesters demonstrated good biocompatibility as non-toxic catalysts and/or solvents involved in the reaction, and the monomers used are endogenous to human metabolism which can be resorbed and metabolized in various physiological pathways. This review summarizes the polyol-based biodegradable polyesters that were synthesized by catalyst-free polyesterification.

Effect of chemical heterogeneity of biodegradable polymers on surface energy: A static contact angle analysis of polyester model films

Biodegradable and bioassimilable poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) derivatives were synthesized and characterized in order to develop a new coating for coronary endoprosthesis enabling the reduction of restenosis. The PDMMLA was chemically modified to form different custom groups in its side chain. Three side groups were chosen: the hexyl group for its hydrophobic nature, the carboxylic acid and alcohol groups for their acid and neutral hydrophilic character, respectively. The sessile drop method was applied to characterize the wettability of biodegradable polymer film coatings. Surface energy and components were calculated. The van Oss approach helped reach not only the dispersive and polar acid-base components of surface energy but also acid and basic components. Surface topography was quantified by atomic force microscopy (AFM) and subnanometer average values of roughness (Ra) were obtained for all the analyzed surfaces. Thus, roughness was considered to have a negligible effect on wettability measurements. In contrast, heterogeneous surfaces had to be corrected by the Cassie-Baxter equation for copolymers (10/90, 20/80 and 30/70). The impact of this correction was quantified for all the wettability parameters. Very high relative corrections (%) were found, reaching 100% for energies and 30% for contact angles.

Stimuli-responsive terpolymer mPEG-b-PDMAPMA-b-PAH mediated co-delivery of adriamycin and siRNA to enhance anticancer efficacy

The adriamycin/P-gp siRNA co-loaded mPEG-b-PDMAPMA-b-PAH terpolymer exhibited pH/reduction dual-responsive payload release behavior and showed a synergistic cytotoxicity against MCF-7/ADR cells.