Recent progress in lactate oxidase-based drug delivery systems for enhanced cancer therapy

Lactate oxidase (LOX) is a natural enzyme that efficiently consumes lactate. In the presence of oxygen, LOX can catalyse the formation of pyruvate and hydrogen peroxide (H2O2) from lactate. This process led to acidity alleviation, hypoxia, and a further increase in oxidative stress, alleviating the immunosuppressive state of the tumour microenvironment (TME). However, the high cost of LOX preparation and purification, poor stability, and systemic toxicity limited its application in tumour therapy. Therefore, the rational application of drug delivery systems can protect LOX from the organism's environment and maintain its catalytic activity. This paper reviews various LOX-based drug-carrying systems, including inorganic nanocarriers, organic nanocarriers, and inorganic-organic hybrid nanocarriers, as well as other non-nanocarriers, which have been used for tumour therapy in recent years. In addition, this area's challenges and potential for the future are highlighted.

Biomaterials Based on Organic Polymers and Layered Double Hydroxides Nanocomposites: Drug Delivery and Tissue Engineering

The development of biomaterials has a substantial role in pharmaceutical and medical strategies for the enhancement of life quality. This review work focused on versatile biomaterials based on nanocomposites comprising organic polymers and a class of layered inorganic nanoparticles, aiming for drug delivery (oral, transdermal, and ocular delivery) and tissue engineering (skin and bone therapies). Layered double hydroxides (LDHs) are 2D nanomaterials that can intercalate anionic bioactive species between the layers. The layers can hold metal cations that confer intrinsic biological activity to LDHs as well as biocompatibility. The intercalation of bioactive species between the layers allows the formation of drug delivery systems with elevated loading capacity and modified release profiles promoted by ion exchange and/or solubilization. The capacity of tissue integration, antigenicity, and stimulation of collagen formation, among other beneficial characteristics of LDH, have been observed by in vivo assays. The association between the properties of biocompatible polymers and LDH-drug nanohybrids produces multifunctional nanocomposites compatible with living matter. Such nanocomposites are stimuli-responsive, show appropriate mechanical properties, and can be prepared by creative methods that allow a fine-tuning of drug release. They are processed in the end form of films, beads, gels, monoliths etc., to reach orientated therapeutic applications. Several studies attest to the higher performance of polymer/LDH-drug nanocomposite compared to the LDH-drug hybrid or the free drug.

Topology dependent modification of layered double hydroxide for therapeutic and diagnostic platform

Layered double hydroxide is a family of two-dimensional materials with wide range of compositions. Recently, its ability to accommodate various chemical species and biocompatibility have been attracted in the biomedical applications to develop drug delivery system and nanodiagnostics. In this review, we categorized biomedical approaches of layered double hydroxide with respect to the three topologies of, namely, interlayer space, outer surface with particle edge, and the lattice points. There have been extensive researches on the intercalation of drug or tracing to make use of interlayer space of layered double hydroxide for drug stabilization, sustained release, cellular delivery and etc. Outer surface or edge has been utilized to immobilization of large therapeutic moieties and to attach tracing moiety. Lattice points consisting of various metal species could be utilized for the specific metal species like paramagnetic elements or radioisotopes. Based on these topologies in layered double hydroxide, both the synthetic routes and the achieved functionalities in terms of biomedical application will be discussed.

Magnetic layered double hydroxide nanosheet as a biomolecular vessel for enzyme immobilization

Magnetic nanoparticle coated with manganese‑aluminum layered double hydroxide (Fe3O4/Mg-Al-CO3-LDH) was prepared and used as porous support for ficin (EC 3.4.22.3) as a model enzyme. Structural characteristics were studied by XRD, FTIR, SEM and light scattering. The quantity of immobilized ficin on the mentioned LDH and non-magnetic LDH was measured and enzyme activity, stability and reusability were compared. Results revealed that the core and shell structure of Fe₃O₄/Mg-Al-CO₃-LDH makes it better dispersion compared to the pristine Mg-Al-CO₃-LDH. Ficin showed strong affinity to absorption of the surface of mentioned LDHs nanosheet especially magnetic LDH, confirmed that the existence of Fe₃O₄ in the core structure of magnetic Fe₃O₄/Mg-Al-CO₃-LDH caused better dispersion of LDH nanocrystal shell compared to pristine LDH moreover, enzyme which immobilized on the magnetic LDH supports, can be recovered by magnetic interaction. The storage stability of free ficin, immobilized ficin on the Mg-Al-CO₃-LDH and Fe₃O₄/Mg-Al-CO₃-LDH during a period of 120 days lost about 75%, 30%, and 20% of their initial activities, respectively.

One-pot synthesis of the organomodified layered double hydroxides - glibenclamide biocompatible nanoparticles

In this work, synthesis of sodium dodecyl sulfate (SDS) organomodified LDH Zn₂Al carrying glibenclamide (GLIB) was performed in one step and in one-pot to obtain nanoparticles (NP). XRD data showed GLIB adsolubilization (d = 14.03 Å) and NP coating with Eudragit L100®. In addition, thermal and XRD data showed exfoliated/intercalated nanocomposite for NP S5 (LDH associated with SDS and Eudragit L100®). LDH organophilization and GLIB intercalation reduced surface area (SBET 23.58 m²/g) and NP size (469 nm). In addition, the change in zeta potential (-35.5 ζ) relative to pristine LDH (SBET 41.34 m²/g, 688.8 nm and +14 ζ) indicated that LDH functionalization seems an appropriate approach to produce NP with greater colloidal stability and enhanced functionality. The zinc release data from the LDH matrix (2.96 % ±0.002 ppm) showed the effectiveness of the coating in acid medium (pH 1.2) and the release data from GLIB showed the kinetics of release of zero order with release in simulated intestinal medium (pH 7.4) of 88 % and 73 % (24 h) for uncoated and coated NP, respectively. All NP were considered biocompatible in the WST-1 assay on BALB 3T3 fibroblast strains making these NP promising therapeutically.

A closer look into the physical interactions between lipid membranes and layered double hydroxide nanoparticles

Layered double hydroxide nanoparticles (LDH-NPs) constitute promising nanocarriers for drug and gene delivery. Although their cell internalization has been studied, the interaction between LDH-NPs and biological membrane models, such as giant unilamellar vesicles (GUVs), remains unexplored. These vesicles are widely-used membrane models that allow minimizing the complexity and uncertainty associated with biological systems to study the physical interactions in the absence of cell metabolism effects. With such an approach the physicochemical properties of the membrane can be differentiated from the biological functionalities involved in cell internalization and the membrane-mediated internalization can be directly understood. In this work, we describe for the first time the interaction of LDH-NPs with freestanding negatively charged POPC:POPS GUVs by fluorescence microscopy. The experiments were performed with fluorescein labeled LDH-NPs of about 100 nm together with different fluorophores in order to evaluate the NPs interactions with the vesicles as well as their impact on the membrane morphology and permeability. Positively charged LDH-NPs are electrostatically accumulated at the GUVs membrane, altering its lateral phospholipid distribution and increasing the stiffness and permeability of the membrane. The adsorption of albumin (LDH@ALB) or polyacrylic acid (LDH@PA) passivates the surface of LDH-NPs eliminating long-range electrostatic attraction. The absence of membrane-mediated internalization of either LDH@ALB or LDH@PA, represents an advantage in the use of LDH-NPs as drug or nucleic acids nanocarriers, because suitable functionalization will allow an optimal cell targeting.

Hydrotalcite–PLGA composite nanoparticles for loading and delivery of danshensu

As one of the main pharmacodynamic components present in the water-soluble components of Salvia miltiorrhiza (Danshen), danshensu (DSS) is applicable to treating cardiovascular diseases.

Synthesis, Formulation, and Characterization of Doxorubicin-Loaded Laponite/Oligomeric Hyaluronic Acid-Aminophenylboronic Acid Nanohybrids and Cytological Evaluation against MCF-7 Breast Cancer Cells

As a synthetic clay material, laponite RDS (LR) was investigated as an effective drug carrier as a result of the special nanodisk structure together with the negative-charged surface to achieve enhanced cellular uptake and targeted delivery. In this research work, the synthesized oligomeric hyaluronic acid-aminophenylboronic acid (oHA-APBA) was entangled onto LR nanodisks to fabricate a valid targeted platform for breast cancer therapy. Briefly, through the formation of amide bonds, 3-APBA was connected to the chain of oHA with a substituted ratio of 4.0 ± 0.2% to synthesize oHA-APBA copolymer. Thereafter, doxorubicin (DOX) was inserted into the interlayer space of LR by the way of the ion exchange process, followed by an assembly with oHA-APBA as a targeted protection layer. The satisfactory drug encapsulation efficiency (> 80%) and narrow size distribution were achieved. The in vitro drug release study demonstrated the release of DOX from DOX@LR/oHA-APBA was sustained and acid dependent. In addition, after fitting the drug cumulative release of DOX@LR/oHA-APBA under different pH conditions with several kinetic models, it was identified that drug release from DOX@LR/oHA-APBA nanohybrids at pH 5.0 was mainly dependent on both diffusion and ion exchange effects. However, under the condition of pH 7.4, the drug was most efficiently released by diffusion effect. Importantly, DOX@LR/oHA-APBA showed remarkable cellular uptake and intracellular drug distribution in MCF-7 cells, which were consistent with inhibitory ability against MCF-7 cells. Hence, the high DOX loading capacity and enhanced cellular tracking can enlighten LR/oHA-APBA as an effective drug delivery carrier for breast cancer therapy.

Assembly of nitroreductase and layered double hydroxides toward functional biohybrid materials

The development of new multifunctional materials integrating catalytically active and selective biomolecules, such as enzymes, as well as easily removable and robust inorganic supports that allow their use and reuse, is a subject of ongoing attention. In this work, the nitroreductase NfrA2/YncD (NR) from Bacillus megaterium Mes11 strain was successfully immobilized by adsorption and coprecipitation on layered double hydroxide (LDH) materials with different compositions (MgAl-LDH and ZnAl-LDH), particle sizes and morphologies, and using different enzyme/LDH mass ratios (Q). The materials were characterized and the immobilization and catalytic performance of the biohybrids were studied and optimized. The nitroreductase-immobilized on the nanosized MgAl-LDH displayed the best catalytic performance with 42-46% of catalytic retention and>80% of immobilization yield at saturation values of enzyme loading Cs ≈ 0.6 g NR/g LDH (Q = 0.8). The adsorption process displayed high enzyme-LDH affinity interactions yielding to a stable biohybrid material. The increase in the amount of enzyme loading favoured the catalytic performance of the biohybrid due to the better preservation of the native conformation. The biohybrid was reused several times with partial activity retention after 4 cycles. In addition, the biohybrid was successfully dried maintaining the catalytic activity for several weeks when it was stored in its dry form. Finally, thin films of NR@LDH biohybrid deposited on glassy carbon electrodes were evaluated as a modified electrode applied for nitro-compound detection. The results show that these biohybrids can be used in biotechnology applications to efficiently detect compounds such as dinitrotoluene. The search for new non-hazardous chemical designs preventing or reducing the use of aggressive chemical processes for human being and the environment is the common philosophy within sustainable chemistry.

Effect of the protein corona on the colloidal stability and reactivity of LDH-based nanocarriers

The physicochemical properties of drug nanocarriers such as layered double hydroxides nanoparticles (LDH-NPs) determine their circulation times in biological media and their interaction with the targeted cells.

Starch Biocatalyst Based on α-Amylase-Mg/Al-Layered Double Hydroxide Nanohybrids

The design of new biocatalysts through the immobilization of enzymes, improving their stability and reuse, plays a major role in the development of sustainable methodologies toward the so-called green chemistry. In this work, α-amylase (AAM) biocatalyst based on Mg3Al-layered double-hydroxide (LDH) matrix was successfully developed with the adsorption method. The adsorption process was studied and optimized as a function of time and enzyme concentration. The biocatalyst was characterized, and the mechanism of interaction between AAM and LDH, as well as the immobilization effects on the catalytic activity, was elucidated. The adsorption process was fast and irreversible, thus yielding a stable biohybrid material. The immobilized AAM partially retained its enzymatic activity, and the biocatalyst rapidly hydrolyzed starch in an aqueous solution with enhanced efficiency at intermediate loading values of ca. 50 mg/g of AAM/LDH. Multiple attachments through electrostatic interactions affected the conformation of the immobilized enzyme on the LDH surface. The biocatalyst was successfully stored in its dry form, retaining 100% of its catalytic activity. The results reveal the potential usefulness of a LDH compound as a support of α-amylase for the hydrolysis of starch that may be applied in industrial and pharmaceutical processes as a simple, environmentally friendly, and low-cost biocatalyst.