Release Of Macromolecules Research Articles

Rheology study of the starch gelatinization to understand the hematite depression process

Gelatinization of starch by NaOH is an essential stage for this depressant preparation to enhance its water solubility through the reverse cationic flotation. No investigation has explored the rheology of the starch gelatinization to demonstrate the hematite depression completeness. To fill the gap, this study examined the influence of a wide range of SNMRs (3:1, 5:1, 7:1, 9:1) to explore the efficiency of the gelatinization process. The main aim was to highlight how starch gel preparation can influence hematite depression in cationic reverse flotation. The steady and dynamic shear rheological measurements plus optical micrographs were assessed for the starch gel gelatinization process for different SNMR conditions. Various experiment outcomes indicated that through the starch gelatinization by SNMR>6:1, the solubilization did not occur completely (due to the presence of some pristine granules) and the gels exhibited solid-like behavior, as evidenced by K′>K″,tanδ < 1, λ≥ 94.3s, and η0≥ 32.0 Pa s. The incomplete release of AP macromolecules into the solution was the cause of the poor hematite depression efficiency. Pretreating starch by SNMR ≤5:1 indicated a full release of both AM and AP species to the solution since the gels showed fluid-like behavior with K′<K″,tanδ >1, λ≤ 0.7s, and η0≤ 2.4 Pa s. However, the excessive alkalinity promoted a reduction in the hydrodynamic size of macromolecules. These findings explain the better efficiency of SNMR = 5:1 to depress hematite compared to SNMR = 3:1. In general, starch preparation with SNMR = 6:1 marked the onset of the sol-gel transition, and the gels exhibited a balance between fluid-like behavior and solid-like behavior.

Retraction Note: Soft nanotube hosts for capsulation and release of molecules, macromolecules, and nanomaterials

Retraction Note: Soft nanotube hosts for capsulation and release of molecules, macromolecules, and nanomaterials

Injectable dECM-enhanced hyaluronic microgels with spatiotemporal release of cartilage-specific molecules to improve osteoarthritic chondrocyte’s function

The interior environment of articular cartilage in osteoarthritis (OA) presents substantial hurdles, leading to the malfunction of chondrocytes and the breakdown of collagen II-enriched hyaline cartilage matrix. Despite this, most clinical treatments primarily provide temporary relief from OA discomfort without arresting OA progression. This study aimed to alleviate OA by developing intra-articular injectable dECM-enhanced hyaluronic (HE) microgels. The HE hydrogel was engineered and shaped into uniformly sized microgels using microfluidics and photopolymerization techniques. These microgels provided a spatiotemporal cascade effect, facilitating the rapid release of growth factors and a slower release of ECM macromolecules and proteins. This process assisted in the recovery of OA chondrocytes’ function, promoting cell proliferation, matrix synthesis, and cartilage-specific gene expression in vitro. It also effectively aided repair of the collagen II-enriched hyaline cartilage and significantly reduced the severity of OA, as demonstrated by radiological observation, gross appearance, histological/immunohistochemical staining, and analysis in an OA rat model in vivo. Collectively, the HE injectable microgels with spatiotemporal release of cartilage-specific molecules have shown promise as a potential candidate for a cell-free OA therapy approach.Graphical

Biophysical features of using a recombination sensor to detect lactate dehydrogenase: sensitivity mechanisms analysis

Background. Most pathologies of the human body (in particular, malignant neoplasms, myocardial hypoxia, liver diseases, etc.) are accompanied by a violation of the integrity of cells in target tissues and the release of intracellular macromolecules into the extracellular environment. Thus, an important diagnostic and prognostic indicator is the level of activity of certain enzymes in blood serum, which are normally intracellular. One of the most promising areas of modern medical electronics and biophysics is the development and optimization of enzyme screening methods in biological fluids. In this study, we aimed to investigate the biophysical characteristics of using a recombination sensor for determining LDH activity in biological fluids. Materials and Methods. Experiments were performed on preparations of standard human blood serum. The reference determination of lactate dehydrogenase activity was carried out photometrically based on the change (decrease) in the concentration of the reduced form of the NADH coenzyme. The passage of the lactate dehydrogenase reaction was experimentally recorded by measuring the photocurrent of a silicon structure with a buried barrier under light irradiation from the region of strong absorption (λ = 532 nm). Results. The biophysical features of the device were studied. The detection of lactate dehydrogenase becomes possible due to the transfer of a hydrogen ion from nicotinamide adenine dinucleotide (NADH) to pyruvate, as a result of which lactate and NAD+ are formed. The effect is explained by the local electrostatic influence on the parameters of the recombination centers in the near-surface bending zone near the silicon surface, which leads to a change in the surface recombination rate. Conclusions. Our approach can be considered as a promising way to develop a highly sensitive method for the detection of lactate dehydrogenase. It has been experi­mentally shown that effective detection is possible in two changes at the surface ben­ding of the deep barrier silicon substrate zone.

Impact of high hydrostatic pressure and ultrasounds technologies in the autolytic process of Saccharomyces cerevisiae in a model wine system

Autolysis plays a crucial role as a technological tool in the ageing process of specific wines. This includes white, red and sparkling wines. During ageing on the lees, yeasts release different compounds that positively modify the composition of the wine. However, traditional autolytic methods can be time-consuming. This work evaluates the use of different ultrasound (US) and high hydrostatic pressure (HHP) treatments to expedite the autolytic process in Saccharomyces cerevisiae in a model wine system. The results suggest that treating yeast cells with US resulted in a faster release of nucleic acids, proteins, and total polysaccharides compared to HHP treatment. The environmental scanning electron microscopy (ESEM) of the treated lees demonstrated that the impact on the yeast cell surface was more pronounced after exposure to US compared to treatments involving HHP. In conclusion, under these conditions the US treatment effectively triggered autolysis in the wine yeast strain, facilitating the release of macromolecules in a model wine.

The role of lipid oxidation pathway in reactive oxygen species-mediated cargo release from liposomes.

Reactive oxygen species (ROS)-mediated photooxidation is an efficient method for triggering a drug release from liposomes. In addition to the release of small molecules, it also allows the release of large macromolecules, making it a versatile tool for controlled drug delivery. However, the exact release mechanism of large macromolecules from ROS-sensitive liposomes is still unclear. There are no studies on the effect of lipid oxidation on the release of cargo molecules of different sizes. By using HPLC-HRMS method we analyzed the oxidation products of ROS-sensitive DOTAP lipid in phthalocyanine-loaded DOTAP:Cholesterol:DSPE-PEG liposomes after 630 nm light irradiation of different durations. Shorter illumination time (1-2 minutes) led to the formation of hydroperoxides and vic-alcohols predominantly. Longer 9-minute irradiation resulted already in aldehydes generation. Interestingly, the presence of epoxides/mono-hydroperoxides and vic-alcohols in a lipid bilayer ensured a high 90% release of small hydrophilic cargo molecules i.e. calcein, but not large (≥10 KDa) macromolecules. Oxidation till aldehydes was mandatory to deliver e.g. dextrans of 10-70 kDa with ca. 30% efficiency. Molecular dynamics simulations revealed that the formation of aldehydes is required to form pores or even fully disrupt the lipid membrane, while e.g. presence of hydroperoxides is enough to make the bilayer more permeable just for water and small molecules. This is an important finding that shed a light on the release mechanism of different cargo molecules from ROS-sensitive drug delivery systems.

Vacuolated coacervate mediates the bimodal release kinetics of diverse macromolecular drugs in vivo

Developing a generalizable delivery system for mediating the multimode release kinetics of diverse macromolecular drugs of varying attributes is highly desired for treating various diseases. We utilized a vacuolated coacervate, in which a dense coacervate matrix functions as a molecularly crowded barrier to regulate the release rate of macromolecules preloaded in the vacuoles. The transient disruption of the coacervate matrix by ultrasound can open the vacuoles to trigger burst release of macromolecular cargoes both in vitro and in vivo, while the liquidity of the nanoparticle-assembled coacervate (named NPA coacervate hereafter) enables the coacervate matrix to be quickly recovered in seconds upon pausing ultrasound, restoring long-term linear release of macromolecules segregated within the vacuoles. Considering the liquid and water-immiscible nature of coacervates, we believe that the concept of a “vacuolated coacervate-based macromolecular reservoir” to regulate macromolecular release kinetics can be highly instrumental in the treatment of diverse diseases.

Photoresponsive liposomes and LipoParticles by incorporating a photosensitizer agent in their lipid membrane

Liposomes, as self-assembled lipid layer vesicles, have emerged as a promising platform for various biomedical applications such as photodynamic therapy (PDT). LipoParticles are core–shell lipid assemblies with a solid polymer core coated by a lipid membrane, which gather the advantages of both their counterparts. Photosensitizers (PS), used in PDT, are photosensitive molecules than can be activated by an exposure to a light source, leading to the death of pathogenic surrounding cells. In this context, the aim of this study is to elaborate liposomes and LipoParticles incorporating a PS, and to examine their resulting photoresponsive properties by following the release, triggered by an UV irradiation, of incorporated fluorescent (macro)molecules. Al(III) phthalocyanine chloride disulfonic acid (AlPcS2) was chosen as PS, and the release of 5(6)-carboxyfluorescein (CF) or bovine serum albumin conjugated with fluorescein isothiocyanate (BSA-FITC) from liposomes and poly (lactic-co-glycolic acid) (PLGA) core of LipoParticles respectively, was investigated by fluorescence spectroscopy. The results have shown that UV irradiation led to the release of CF molecules depending on the membrane lipid formulation, and that repeated irradiations could increase the amount of CF molecules released from liposomes. The main parameters governing the release of BSA-FITC macromolecules from LipoParticles were the temperature of their elaboration (corresponding to a reorganization of several liposomes on the surface of PLGA particles), the initial PS concentration, and the duration of UV irradiation. Best results were found with a temperature of the LipoParticles elaboration of 20 °C, a PS concentration of 0.1 mM, and a duration of irradiation of 5 min. These results support the fact that similarly to liposomes, LipoParticles can also be endowed with photoresponsive properties, which positions them as interesting nanovectors for PDT.

Stochastic Lattice-Based Modeling of Macromolecule Release from Degradable Hydrogel.

A three-dimensional lattice-based model has been developed to describe the release of a macromolecular drug encapsulated in a degradable hydrogel. The degradation-induced network heterogeneity is considered by assigning varying diffusion coefficients to the lattice sites based on the fitted exponential node-diffusivity relationship. As time passes, due to the degradation of crosslink nodes, diffusivity values in lattice sites progress to higher values. To overcome the size limitation of the computational model and to compare it with experimental data, a scaling ratio based on the random walk equation is developed. The model was able to describe the experimental release data from chemically crosslinked dextran hydrogels. The results showed that the effect of the initial network and the chemistry of crosslink nodes (hydrolysis rate) on the drug release profile cannot be decoupled.

Antibacterial activity of Chinese propolis and its synergy with β-lactams against methicillin-resistant Staphylococcus aureus.

Propolis has exhibited effective antibacterial activities in preventing the growth of multiple pathogenic bacteria. However, the antibacterial activity of Chinese propolis against methicillin-resistant Staphylococcus aureus (MRSA) is almost unknown. The present study aimed to explore the antibacterial activity and action mechanism of Chinese propolis ethanol extract (CPEE) against MRSA. Thirteen compounds of CPEE were identified using HPLC-DAD/Q-TOF-MS, and none of them showed better anti-MRSA activity than CPEE. The diameter of inhibition zone (DIZ) of CPEE was 20.1mm. The minimal inhibitory concentration (MIC) of CPEE was 32mg/L, while the minimal bactericidal concentration (MBC) against MRSA was 64mg/L. Moreover, CPEE showed significant synergistic effects with β-lactam antibiotics (ampicillin and oxacillin). Nucleic acid and protein leakage assays showed that CPEE can stimulate the release of intracellular macromolecules by damaging the cell membrane integrity of MRSA. Live/dead-staining and SDS-PAGE assays further confirmed that CPEE could inhibit bacterial activities by disrupting the membrane. The reduction in PBP2a expression and β-lactamase activity, as shown by western blot and β-lactamase detection assays, suggested that CPEE was able to reverse the drug resistance of MRSA. These results demonstrated the anti-MRSA activity of CPEE was mainly due to changing the cell membrane and reversing resistance, which indicates that CPEE could be an attractive candidate for use in future food and medical applications.

The Antibacterial Activity of Thymol Against Drug-Resistant Streptococcus iniae and Its Protective Effect on Channel Catfish (Ictalurus punctatus).

Streptococcus iniae is a zoonotic pathogen, which seriously threatens aquaculture and human health worldwide. Antibiotics are the preferred way to treat S. iniae infection. However, the unreasonable use of antibiotics leads to the enhancement of bacterial resistance, which is not conducive to the prevention and treatment of this disease. Therefore, it is urgent to find new efficient and environmentally friendly antibacterial agents to replace traditional antibiotics. In this study, the antibacterial activity and potential mechanism of thymol against S. iniae were evaluated by electron microscopy, lactate dehydrogenase, DNA and protein leakage and transcriptomic analysis. Thymol exhibited potent antibacterial activity against S. iniae in vitro, and the MIC and MBC were 128 and 256μg/mL, respectively. SEM and TEM images showed that the cell membrane and cell wall were damaged, and the cells were abnormally enlarged and divided. 2MIC thymol disrupted the integrity of cell walls and membranes, resulting in the release of intracellular macromolecules including nucleotides, proteins and inorganic ions. The results of transcriptomic analysis indicated that thymol interfered with energy metabolism and membrane transport, affected DNA replication, repair and transcription in S. iniae. In vivo studies showed that thymol had a protective effect on experimental S. iniae infection in channel catfish. It could reduce the cumulative mortality of channel catfish and the number of S. iniae colonization in tissues, and increase the activities of non-specific immune enzymes in serum, including catalase, superoxide dismutase, lysozyme and acid phosphatase. Taken together, these findings suggested that thymol may be a candidate plant agent to replace traditional antibiotics for the prevention and treatment of S. iniae infection.

A biphasic mathematical model for the release of polymer-drug conjugates from poly(vinyl alcohol) hydrogels

BackgroundHydrogels are a popular vehicle for controlled drug release. In comparison with small-soluble drugs of simple diffusion, the release of large polymer-drug conjugates is more complex and could not be predicted by a simple diffusion model. This study was aimed at mathematical modeling of the release of polymer-drug conjugates to design controlled drug-release hydrogel systems. MethodsFluorescein was used as a small model drug, whereas fluorescein isothiocyanate-dextran acted as a polymer-drug conjugates. The molecules were encapsulated in poly(vinyl alcohol)-based hydrogels with different concentrations and degrees of crosslinking. The release data were fitted using a one-diffusion coefficient (1DC) model and a two-diffusion coefficient (2DC) model, performed by Matlab. Significant findingsThe simple 1DC model fitted the release data of small molecules (< 10 kDa) very well, while the more complex 2DC model was needed to predict the release of macromolecules (10–250 kDa) for a better fit. The 2DC model proposed that a hydrogel is a heterogeneous structure with dense and loose areas, and macromolecules diffuse through the two areas with different diffusivity. We further demonstrated that the biphasic model could be applied to design hydrogel systems for precision drug release profiles.

Age, obesity and hyperglycaemia: Activation of innate immunity initiates a series of molecular interactions involving anionic surfaces leading to COVID-19 morbidity and mortality

Obesity and type 2 diabetes are major factors in COVID-19 causing a progression to excessive morbidity and mortality. An important characteristic of these conditions is poor glycaemic control leading to inappropriate chemical reactions and the production of glycated proteins in which positively charged lysine and arginine residues are neutralised. We propose that this protein glycation primes the inflammatory system as the presence of aspartate and glutamate residues in any glycated zwitterionic protein will thus increase its anionic characteristics. As a result, these macromolecules will be recognised by the innate immune system and identified as originating from infection or cell damage (sterile inflammation). Many proteins in the body exist to non-specifically target these anionic macromolecules and rely heavily on positively charged (cationic) binding-sites to produce a relatively non-specific interaction as the first step in the body’s response. Proteins involved in this innate immunity are collectively referred to as damage associated molecular pattern molecules or pathogen associated molecular pattern molecules. A crucial player in this process is RAGE (Receptor for Advanced Glycation End products). RAGE plays a central role in the inflammatory response and on ligand binding stimulates many aspects of inflammation including the production of the key inflammatory mediator NF-κB, and the subsequent production of inflammatory cytokines. This process has the potential to show a positive feedback loop resulting in a dramatic response within the tissue. We propose that protein glycation primes the inflammatory system by generating negatively charged surfaces so that when a SARS-Cov-2 infection occurs within the lung the further release of negatively-charged macromolecules due to cell damage results in a potentially catastrophic inflammatory response resulting in the cytokine storm associated with COVID-19 morbidity and mortality. That part of the population who do not suffer from inflammatory priming (Phase 1), such as the young and the non-obese, should not be subjected to the catastrophic inflammatory response seen in others (Phase 2). This hypothesis further highlights the need for improved dietary intake to minimise the inflammatory priming resulting from poor glycaemic control.

Fabrication and development of controlled release PLGA microneedles for macromolecular delivery using FITC-Dextran as model molecule

The use of biodegradable polymers has been prominent in the field of drug delivery due to its degradability and biocompatible properties. These polymers when used to prepare microneedles, impart high mechanical strength, sustained drug release profile, and long term biocompatibility. In this study, PLGA (poly (D, L-lactic co-glycolic acid)) and PVA (Polyvinyl Alcohol) were used in combination to optimize the microneedle fabrication for high molecular weight FITC Dextran (4 kDa MW) to be used as a model drug. FITC-Dextran loaded PLGA microneedles were fabricated using a mold casting technique. MNs were characterized for the textural properties, FITC-Dextran release profile, and in-vitro permeation profile. The fate of microneedles in the skin (ex vivo) was characterized using fluorescence and confocal imaging. The FITC -Dextran MNs (10 × 10 array) had a dimension of 415 ± 2.65 μm height, 207 ± 1.63 μm width of the base and a needle pitch of 463 ± 1.45 μm. The texture analysis data showed puncture force for FITC-Dextran loaded PLGA microneedles (28.46 ± 0.23 g) and PLGA microneedles (16.92 ± 0.04 g). The Cumulative permeation of FITC-Dextran after 48 h was 2.34 ± 0.40 μg/cm2 and it showed a 31 fold higher permeation profile than its respective control. Ex vivo imaging studies were used to characterize the fluorescence intensity of FITC-Dextran in the skin. This study demonstrates that incorporating higher molecular weight molecules into PLGA microneedles proved to be an effective strategy to sustain the release of macromolecules across stratum corneum/epidermis for transdermal delivery.

Viral use and subversion of membrane organization and trafficking.

Membrane trafficking is an essential cellular process conserved across all eukaryotes, which regulates the uptake or release of macromolecules from cells, the composition of cellular membranes and organelle biogenesis. It influences numerous aspects of cellular organisation, dynamics and homeostasis, including nutrition, signalling and cell architecture. Not surprisingly, malfunction of membrane trafficking is linked to many serious genetic, metabolic and neurological disorders. It is also often hijacked during viral infection, enabling viruses to accomplish many of the main stages of their replication cycle, including entry into and egress from cells. The appropriation of membrane trafficking by viruses has been studied since the birth of cell biology and has helped elucidate how this integral cellular process functions. In this Review, we discuss some of the different strategies viruses use to manipulate and take over the membrane compartments of their hosts to promote their replication, assembly and egress.

Electrostatically Driven Topological Freezing of Polymer Diffusion at Intermediate Confinements.

Breaking the paradigm that polymers in crowded aqueous media obey Einstein's law of diffusion, we report a localized nondiffusive hierarchical metastable state at intermediate confinements. Combining electrostatic and topological effects, we can tune the propensity of this new universality class in a quasicoacervate gel system consisting of guest polyamino acid chains inside an oppositely charged host hydrogel. Our observations offer strategies for controlled release and retention of macromolecules in aqueous crowded media, while opening a new direction for understanding topologically frustrated dynamics in polymers and other soft matter systems.

Antimicrobial Activity and Proposed Action Mechanism of Linalool Against Pseudomonas fluorescens.

In this study, linalool, one of the principal components of essential oils, was used as an antibacterial agent to investigate the antibacterial activity and mechanism of linalool against Pseudomonas fluorescens. The reduction in membrane potential (MP), leakage of alkaline phosphatase (AKP) and the release of macromolecules, including DNA, RNA and protein confirmed that damage to cell wall membrane structure and leakage of cytoplasmic contents were due to the linalool treatment. Furthermore, the decrease of enzyme activity, including the succinate dehydrogenase (SDH), malate dehydrogenase (MDH), pyruvate kinase (PK), and ATPase indicated that linalool could lead to metabolic dysfunction and inhibit energy synthesis. In addition, the activity of respiratory chain dehydrogenase and metabolic activity of respiration indicated that linalool inhibits cellular respiration. These results revealed that linalool had strong antibacterial activity against P. fluorescens via membrane damage, bacterial metabolic and oxidative respiratory perturbations, interfering in cellular functions and even causing cell death. It was suggested that linalool may be a new potential source as food antiseptics in food systems.

Hyaluronic Acid and Poly-l-Lysine Layers on Calcium Alginate Microspheres to Modulate the Release of Encapsulated FITC-Dextran.

Alginate solutions crosslink into microspheres in calcium alginate, enabling the encapsulation and subsequent release of biological macromolecules and drugs. However, release from calcium alginate into PBS is relatively fast because it will decrosslink the gel relatively quickly. In this research, FITC-dextran (MW 10kDa) was encapsulated in 2% (w/v) calcium alginate microspheres by electrospraying. The resulting microspheres (diameter=247±13μm) were then layered with thin polyelectrolyte films of hyaluronic acid (HA) and poly-l-lysine (PLL) to attempt to slow the diffusion of FITC-dextran out of the microspheres and the coating parameters were modified to modulate diffusion and release. Increasing the concentration of FITC-dextran encapsulated in the microspheres resulted in an increase in its release over time into PBS. Crosslinking PLL/HA layers on the microspheres did not decrease the invitro release rates of encapsulated FITC-dextran into PBS. Increasing the number of layers on the microspheres from 3 to 5 layers significantly decreased the amount of encapsulated FITC-dextran released. However, increasing the number of layers to 7 did not further sustain the release of FITC-dextran, likely because these microspheres collapsed to a smaller size during the coating procedure, resulting in release controlled by both diffusion and swelling. Multiple layers of PLL and HA provided a robust mechanism to sustain and control release of large molecules from calcium alginate.

Oviductal regulation of fertilization and early embryonic development

During the period of late follicular development and the first four days of the oestrous cycle, the oviduct occupies a central role in the establishment of pregnancy. Oviductal function is regarded as being either 'passive' or biologically active, providing an environment that sustains and enhances fertilization and early cleavage-stage embryonic development. Recent reports have focused on this microenvironment and shown that ovarian steroids induce marked morphological, physiological and biochemical changes. Alterations include changes in the biosynthetic activity and release of macromolecules by the oviductal epithelium which become part of the luminal microenvironment. Furthermore, both regional and temporal differences in activity and protein production occur through hormonal changes during the oestrous cycle and early pregnancy. Studies on identification, characterization and regulation of several proteins synthesized de novo have indicated oocyte-oviduct and embryo-oviduct interactions. However, the identification of oviduct-derived proteins, their regulation and their potential function in vivo needs to be examined. Studies in other species also suggest roles for growth factors in early embryonic development, but little information is available for the pig. We propose that ovarian hormones control changes in synthetic activity, synthesis of some oviduct-derived proteins and the presence of specific factors in the luminal microenvironment which sustain and enhance fertilization and early cleavage-stage embryonic development.

Encapsulation of Low-Molecular-Weight Drugs into Polymer Multilayer Capsules Templated on Vaterite CaCO3 Crystals.

Polyelectrolyte multilayer capsules (PEMCs) templated onto biocompatible and easily degradable vaterite CaCO3 crystals via the layer-by-layer (LbL) polymer deposition process have served as multifunctional and tailor-made vehicles for advanced drug delivery. Since the last two decades, the PEMCs were utilized for effective encapsulation and controlled release of bioactive macromolecules (proteins, nucleic acids, etc.). However, their capacity to host low-molecular-weight (LMW) drugs (<1–2 kDa) has been demonstrated rather recently due to a limited retention ability of multilayers to small molecules. The safe and controlled delivery of LMW drugs plays a vital role for the treatment of cancers and other diseases, and, due to their tunable and inherent properties, PEMCs have shown to be good candidates for smart drug delivery. Herein, we summarize recent progress on the encapsulation of LMW drugs into PEMCs templated onto vaterite CaCO3 crystals. The drug loading and release mechanisms, advantages and limitations of the PEMCs as LMW drug carriers, as well as bio-applications of drug-laden capsules are discussed based upon the recent literature findings.