Use Of Microparticles Research Articles

Trojan Microparticles : A Composite Nanoparticle Delivery System

Abstract: In recent years, microparticulate systems have drawn growing attention as a viable strategy for delivering cells, proteins, and medications to target areas. The Nanoparticles-in-Microparticles System (NiMS) is a drug delivery method that combines nano- and microparticles to deliver medications or genes to particular bodily regions with precision. A promising method for achieving dual or multiple functions inside a formulation is the development of nanoparticle-in-microparticle systems (NiMS). NiMS comprises a microparticle (M.P.) matrix and one or more nanoparticles (N.P.s). The N.P.s can be designed to provide specific functionality, such as targeted drug delivery or imaging, while the M.P. matrix can be tailored to provide sustained release or protect the N.P.s from degradation. NiMS offer several advantages over traditional formulations, including the ability to control release profiles and achieve site-specific delivery. By combining different types of N.P.s and M.P.s, it is possible to create formulations that release drugs at different rates or with different kinetics, allowing for tailored treatment regimens. Additionally, by lowering off-target effects and boosting efficacy, the site-specific targeting offered by NiMS can enhance the therapeutic index of medications. Microparticles are small, micron-sized particles that can be loaded with therapeutic agents and designed to deliver them to specific tissues in the body. The pharmaceutical sector is developing microparticulate delivery systems for oral, pulmonary, and cutaneous administration. For instance, a promising strategy for treating respiratory conditions, including asthma and chronic obstructive pulmonary disease, is the development of inhalable microparticles (COPD). Moreover, the use of microparticles for topical drug delivery is being studied, where they can be formulated into creams, gels, or patches for treating skin disorders. The composition of microparticles is crucial for successful tissue regeneration because the particles must be biocompatible and able to interact with the cells in the targeted tissue. In addition, the size and shape of the particles can affect their behavior and how they interact with cells. Chemical and biological sensors and devices, optical detectors, electronic components, and nanoscale production depend on nanostructures because they offer unique properties, such as increased surface area and enhanced reactivity, which can be exploited to create more efficient and effective devices.

Thermophysical properties of suspensions with [NI₃(μ₃-PPZA)₄CL₂] metal string complex microparticles

The study investigated the thermophysical properties of suspensions containing Ni₃(μ₃-ppza)4Cl₂ metal string complex (MSC) microparticles in aqueous glycerol solutions. The results showed that the use of microparticles of monocrystalline metal string complexes Ni₃(μ₃-ppza)4Cl₂ and Ni₅(μ₅-pppmda)4Cl₂ leds to the highest thermal conductivity enhancements and a decrease in freezing point. A comparative analysis of thermal conductivity enhancements of suspensions with micro- and nanoparticles was also conducted. Compared to the base fluid, at 5% volume fraction Ni₃-water-glycerol showed a 72% increase in thermal conductivity, while Cu-water-glycerol and Ni5-water-glycerol showed enhancements of 53% and 47%, respectively. The study suggests that the higher stability of suspensions with MSC microparticles, due to the formation of hydrogen bonds between the organic fragments of particles and water molecules, thier lower density and the formation of particle assemblies, is responsible for the significant thermal conductivity enhancement compared to nanofluids. The colloidal structure of suspensions with MSC microparticles greatly affects their thermophysical properties. Keywords: nanofluid, microfluid, metal string complex, thermal conductivity, suspension.

Comparison of Engineered Liver 3D Models and the Role of Oxygenation for Patient-Derived Tumor Cells and Immortalized Cell Lines Cocultured with Tumor Stroma in the Detection of Hepatotoxins.

In metabolically active tumors, responses of cells to drugs are heavily influenced by oxygen availability via the surrounding vasculature alongside the extracellular matrix signaling. The objective of this study is to investigate hepatotoxicity by replicating critical features of hepatocellular carcinoma (HCC). This includes replicating 3D structures, metabolic activities, and tumor-specific markers. The internal environment of spheroids comprised of cancerous human patient-derived hepatocytes using microparticles is modulated to enhance the oxygenation state and recreate cell-extracellular matrix interactions. Furthermore, the role of hepatic stellate cells in maintaining hepatocyte survival and function is explored and hepatocytes from two cellular sources (immortalized and patient-derived) to create four formulations with and without microparticles are utilized. To investigate drug-induced changes in metabolism and apoptosis in liver cells, coculture spheroids with and without microparticles are exposed to three hepatotoxic drugs. The use of microparticles increases levels of apoptotic markers in both liver models under drug treatments. This coincides with reduced levels of anti-apoptotic proteins and increased levels of pro-apoptotic proteins. Moreover, cells from different origins undergo apoptosis through distinct apoptotic pathways in response to identical drugs. This 3D microphysiological system offers a viable tool for liver cancer research to investigate mechanisms of apoptosis under different microenvironmental conditions.

Effect of Microparticles on Fungal Fermentation for Fermentation-Based Product Productions

Ranging from simple food ingredients to complex pharmaceuticals, value-added products via microbial fermentation have many advantages over their chemically synthesized alternatives. Some of such advantages are environment-friendly production pathways, more specificity in the case of enzymes as compared to the chemical catalysts and reduction of harmful chemicals, such as heavy metals or strong acids and bases. Fungal fermentation systems include yeast and filamentous fungal cells based on cell morphology and culture conditions. However, filamentous fungal fermentation has gained attention in the past few decades because of the diversity of microbial products and robust production of some of the most value-added commodities. This type of fungal fermentation is usually carried out by solid-state fermentation. However, solid-state fermentation poses problems during the scale-up for industrial production. Therefore, submerged fermentation for value-added products is usually preferred for scaling-up purposes. The main problem with submerged fungal fermentation is the formation of complex mycelial clumps or pellets. The formation of such pellets increases the viscosity of the media and hinders the efficient transfer of oxygen and nutrient resources in the liquid phase. The cells at the center of the clump or pellet start to die because of a shortage of resources and, thus, productivity decreases substantially. To overcome this problem, various morphological engineering techniques are being researched. One approach is the use of microparticles. Microparticles are inert particles with various size ranges that are used in fermentation. These microparticles are shown to have positive effects, such as high enzyme productivity or smaller pellets with fungal fermentation. Therefore, this review provides a background about the types of microparticles and summarizes some of the recent studies with special emphasis on the fungal morphology changes and microparticle types along with the applications of microparticles in filamentous fungal fermentations.

Multidrug Resistance in Cancer: Understanding Molecular Mechanisms, Immunoprevention and Therapeutic Approaches.

Cancer is one of the leading causes of death worldwide. Several treatments are available for cancer treatment, but many treatment methods are ineffective against multidrug-resistant cancer. Multidrug resistance (MDR) represents a major obstacle to effective therapeutic interventions against cancer. This review describes the known MDR mechanisms in cancer cells and discusses ongoing laboratory approaches and novel therapeutic strategies that aim to inhibit, circumvent, or reverse MDR development in various cancer types. In this review, we discuss both intrinsic and acquired drug resistance, in addition to highlighting hypoxia- and autophagy-mediated drug resistance mechanisms. Several factors, including individual genetic differences, such as mutations, altered epigenetics, enhanced drug efflux, cell death inhibition, and various other molecular and cellular mechanisms, are responsible for the development of resistance against anticancer agents. Drug resistance can also depend on cellular autophagic and hypoxic status. The expression of drug-resistant genes and the regulatory mechanisms that determine drug resistance are also discussed. Methods to circumvent MDR, including immunoprevention, the use of microparticles and nanomedicine might result in better strategies for fighting cancer.

Spatio-Temporal Plasma Afterglow Induces Additional Neutral Drag Force on Microparticles

An emerging topic in complex plasma physics is the interaction between dust particles and afterglow plasmas. Control of plasma-particle interactions and specifically of the particle trajectories is especially relevant for plasma based contamination control applications. In systems where this contamination control is relevant, emerging or applied plasmas can be of highly transient nature, due to which contaminating particles interact with a combination of a spatial and a temporal afterglow plasma. Until now this type of plasmas and the possible interaction with embedded microparticles has remained far from fully explored in literature. In this work we visually record falling microparticles in a spatio-temporal afterglow of a low pressure inductively coupled plasma and observe a sudden and temporary reversal in their vertical velocity. Numerical simulations confirm that this effect is due to the cooling of the heated background gas in the former active plasma region, which creates a pressure wave and causes microparticles in the spatial afterglow to experience an additional neutral drag force in direction of the plasma bulk. Besides being an interesting principle phenomenon, the presence of this effect could have added value for developing plasma-driven particle contamination control applications. Moreover, for a well defined vacuum vessel geometry and plasma heating volume, this enables the use of microparticles in the spatio-temporal afterglow as probe for the neutral gas temperature in plasma.

Preparation and Use of the Iraqi Nano Attapugite Induced by TiO2 for Decontamination Gas Oil (Diesel)

In this paper, the use of nano particles of clay attapulgit be very effective. It is more effective than the use of Micro particles (μm 53) in the decontamination of oil (gas oil) for surface water cracker manner photo-degradation, using xenon lamps of long wavelength (200-800nm) in an atmosphere of oxygen as well as under an atmosphere of nitrogen for comparison purposes. The results of the photo-degradation molecules hydrocarbon long successful were followed using a Gas chromatography (GC) by reference to the standard models (Nonan C9H20, Dodecane C12H26, Hexadecane C16H34), and has been used spectroscopy (FT-IR) to follow changes in the locations groups effective. This study showed the possibility of decomposition of gas oil molecules using attapugite the long as supported and assistant surface to short chains using the rays of light similar to sunlight and then complete the short cracking natural sunlight later.

A Review of the Use of Microparticles for Cartilage Tissue Engineering.

Tissue and organ failure has induced immense economic and healthcare concerns across the world. Tissue engineering is an interdisciplinary biomedical approach which aims to address the issues intrinsic to organ donation by providing an alternative strategy to tissue and organ transplantation. This review is specifically focused on cartilage tissue. Cartilage defects cannot readily regenerate, and thus research into tissue engineering approaches is relevant as a potential treatment option. Cells, scaffolds, and growth factors are three components that can be utilized to regenerate new tissue, and in particular recent advances in microparticle technology have excellent potential to revolutionize cartilage tissue regeneration. First, microspheres can be used for drug delivery by injecting them into the cartilage tissue or joint space to reduce pain and stimulate regeneration. They can also be used as controlled release systems within tissue engineering constructs. Additionally, microcarriers can act as a surface for stem cells or chondrocytes to adhere to and expand, generating large amounts of cells, which are necessary for clinically relevant cell therapies. Finally, a newer application of microparticles is to form them together into granular hydrogels to act as scaffolds for tissue engineering or to use in bioprinting. Tissue engineering has the potential to revolutionize the space of cartilage regeneration, but additional research is needed to allow for clinical translation. Microparticles are a key enabling technology in this regard.

VCAM-1 Target in Non-Invasive Imaging for the Detection of Atherosclerotic Plaques.

Simple SummaryCardiovascular diseases are the first cause of morbimortality worldwide. They are mainly caused by atherosclerosis, with progressive plaque formation in the arterial wall. In this context, several imaging techniques have been developed to screen, detect and quantify atherosclerosis. Early screening improves primary prevention and promotes the prescription of adequate medication before adverse clinical events. In this review, we focus on the imaging of vascular cell adhesion molecule-1, an adhesion molecule involved in the first stages of the development of atherosclerosis. This molecule could therefore be a promising target to detect early atherosclerosis non-invasively. Potential clinical applications are critically discussed.Atherosclerosis is a progressive chronic arterial disease characterised by atheromatous plaque formation in the intima of the arterial wall. Several invasive and non-invasive imaging techniques have been developed to detect and characterise atherosclerosis in the vessel wall: anatomic/structural imaging, functional imaging and molecular imaging. In molecular imaging, vascular cell adhesion molecule-1 (VCAM-1) is a promising target for the non-invasive detection of atherosclerosis and for the assessment of novel antiatherogenic treatments. VCAM-1 is an adhesion molecule expressed on the activated endothelial surface that binds leucocyte ligands and therefore promotes leucocyte adhesion and transendothelial migration. Hence, for several years, there has been an increase in molecular imaging methods for detecting VCAM-1 in MRI, PET, SPECT, optical imaging and ultrasound. The use of microparticles of iron oxide (MPIO), ultrasmall superparamagnetic iron oxide (USPIO), microbubbles, echogenic immunoliposomes, peptides, nanobodies and other nanoparticles has been described. However, these approaches have been tested in animal models, and the remaining challenge is bench-to-bedside development and clinical applicability.

Recombinant Filamentous Bacteriophages Encapsulated in Biodegradable Polymeric Microparticles for Stimulation of Innate and Adaptive Immune Responses.

Escherichia coli filamentous bacteriophages (M13, f1, or fd) have attracted tremendous attention from vaccinologists as a promising immunogenic carrier and vaccine delivery vehicle with vast possible applications in the development of vaccines. The use of fd bacteriophage as an antigen delivery system is based on a modification of bacteriophage display technology. In particular, it is designed to express multiple copies of exogenous peptides (or polypeptides) covalently linked to viral capsid proteins. This study for the first time proposes the use of microparticles (MPs) made of poly (lactic-co-glycolic acid) (PLGA) to encapsulate fd bacteriophage. Bacteriophage–PLGA MPs were synthesized by a water in oil in water (w1/o/w2) emulsion technique, and their morphological properties were analyzed by confocal and scanning electron microscopy (SEM). Moreover, phage integrity, encapsulation efficiency, and release were investigated. Using recombinant bacteriophages expressing the ovalbumin (OVA) antigenic determinant, we demonstrated the immunogenicity of the encapsulated bacteriophage after being released by MPs. Our results reveal that encapsulated bacteriophages are stable and retain their immunogenic properties. Bacteriophage-encapsulated PLGA microparticles may thus represent an important tool for the development of different bacteriophage-based vaccine platforms.

Enhancing β-mannanase production by controlling fungal morphology in the bioreactor with microparticle addition

Beta (β)-mannanase is an industrial enzyme that has a wide range of uses in industry. Chemically, β-mannanase mainly influences the β-1,4-mannose linkages of galactomannans. Many microbes, particularly Aspergillus species, can be utilized to produce mannanases. On the other hand, excessive filamentous clumps of Aspergillus species in bioreactors are difficult to control. Therefore, this study sought to limit the clumps resulted from the excessive fungal growth by adding microparticles into the fermentation medium. Fed-batch fermentations were performed with and without microparticles (control). As a microparticle agent, aluminum oxide (Al2O3) and talc (Mg3Si4O10(OH)2)) were evaluated as to their effect on fermentation performance. The highest β-mannanase activities were 744.35 and 356.79 U/mL for 5 g/L of Al2O3 and talc, which were 14.16- and 6.80-fold greater, respectively than in the control fermentation. Most of the treatments improved the performance of the fermentation process as the microparticles appeared to disturb the initial phase of spore aggregation. The most effective microparticle type and concentration for production of β-mannanase in a stirred tank bioreactor with a glucose-based medium were determined to be 5 g/L of Al2O3. These results indicate that the use of microparticles improve β-mannanase fermentation conditions by controlling excessive fungal growth.

Colección de energía radiante en CPC mejorada con micropartículas

Introduction: The use of energy requires collection systems to improve heat transfer capacity. Objective: To evaluate the effect of the incorporation of microparticles in the process fluid of a compound parabolic collector (CPC) on its ability to operate. Methodology: A CPC incorporated with activated carbon (102.2 nm), Chinese ink (198.4 nm) and copper particles (160.1 nm) was evaluated for operation at four angles of inclination (30, 35, 40 and 45°). Results: The energy collection was based on a natural convection mechanism, with a film coefficient that varied between 10.6 and 15.8 W∙m-2∙°C-1. The operation with 30° inclination showed the best characteristics of radiant energy collection, where the energy efficiency was 44.6 % for the system based on pure water, 61.0 % with copper particles, 63.2 % with activated carbon and 68.4 % with Chinese ink. Limitations of the study: The study provides values of thermal convection coefficients that correspond to the particular conditions evaluated. In order to evaluate the performance of the system under different conditions, it is necessary to build models based on dimensional analysis that allow the evaluation of heat transfer coefficients in situations of use of diverse operating variables. Originality: The incorporation of microparticles in the process fluid increases the potential for collecting radiant energy from a CPC. Conclusions: The use of microparticles has the potential to improve the operation of a CPC.

Nanomodification of structure of non-ferrous metals in mode of superdeep penetration

Abstract. Purpose. To e stablish a mechanism of ultra - deep penetration of substances and to establish the relationship between the parameters of microparticles of micronic smeasures and the deep penetration into reinforced fibers. Basic factors that determine a competitiveness between the producers of construction materials is a row of such indexes, as creation of new effective technologies of production and materials with the new complex of physical and chemical and mechanical properties, cost of energy cutting on the production of new materials and other. One of economically expedient and competitive directions there is development of new technology of creation of composition materials that can be realized in the conditions of high-energy and dynamic influence on matrix material. An effective physical “instrument” that changes physical parameters in the volume of solid is a process of super-deep penetration of microparticless in metals. Methodology. The copper, brass , aluminium alloy AK12 w ere used as samples for matrix material research and subjected it to dynamic processing in ultra - deep penetration mode . The schlifs before and after treatment were examined using electron microscopy, microanalysis, X- ray and phase analysis , mass spectrometry and other physical methods. Findings. In alloys of multi - colored non -ferrous metals in ultra - deep penetration mode , the voluminous doping of parts has been implemented both through the use of microparticles of different compositions and by synthesized new chemical elements and their isotopes. The use of ultra - deep penetration allowed the creation of highly - experienced alloys of non -ferrous metals with a concentration of doping elements from 0,35 mas. % to 26 mas. %. Originality. It has been established that during the bombardment of non -ferrous metals microparticles of different compositions there is a microsecond reduction in the strength of the metal target and local nuclear reactions in the microparticle area. Practical value. The understand ing the mechanisms of ultra - deep penetration of microparticles and reactions of their interaction will allow to create new structural materials with unique properties for the industry. First set that under time micro and nanosecond co-operating of microparticless with metallic targets there are a saltatory decline of viscidity and local nuclear reactions and it will allow at further development of mechanisms of super-deep penetration will allow to create new construction materials and new energy sources.

Stability of Hibiscus Extract Encapsulated by Ionic Gelation Incorporated in Yogurt

Encapsulation techniques can protect active components from degradation during storage while maintaining their functionality. The purpose of this study was to evaluate the use of double emulsion followed by ionic gelation in the encapsulation of the extract of Hibiscus sabdariffa L. anthocyanin (HE) in the application of the microparticles in a yogurt food matrix. The ionic gelation methods used were dripping-extrusion—D (Encapsulator Buchi B-390)—and atomization—A (Spray Dryer Buchi B-290). Double emulsion (HE/rapeseed oil/pectin) and a cross-linked solution (CaCl2) were employed. Yogurt matrix was characterized for total dry matter, total lipids, protein content, total lactic bacteria, pH/acidity, phenolic compounds (Folin-Ciocalteu), total anthocyanins (differential pH), antioxidant activity (DPPH), color (colorimeter), and morphology (optical microscopy) and was subjected to a sensory appearance acceptability test (80 panelists). The samples were stored in the absence of light (5 ± 1 °C) and monitored every 7 days for total polyphenols, total anthocyanins, color, pH/acidity, and syneresis, for a period of at least 30 days. The use of microparticles obtained by double emulsion followed by ionic gelation and incorporated in yogurt matrix presented technical feasibility, providing color and functionality to the product. The yogurt matrix with microparticles obtained by the atomization technique presented high acceptability of appearance. Microparticles obtained by the dripping-extrusion technique showed greater stability of anthocyanins (48%) and color (ΔE = 1.42) during the yogurt matrix shelf life.

Treatment of Surgical Brain Injury by Immune Tolerance Induced by Peripheral Intravenous Injection of Biotargeting Nanoparticles Loaded With Brain Antigens.

Once excessive, neurological disorders associated with inflammatory conditions will inevitably cause secondary inflammatory damage to brain tissue. Immunosuppressive therapy can reduce the inflammatory state, but resulting infections can expose the patient to greater risk. Using specific immune tolerance organs or tissues from the body, brain antigen immune tolerance treatment can create a minimal immune response to the brain antigens that does not excessively affect the body's immunity. However, commonly used immune tolerance treatment approaches, such as those involving the nasal, gastrointestinal mucosa, thymus or liver portal vein injections, affect the clinical conversion of the therapy due to uncertain drug absorption, or inconvenient routes of administration. If hepatic portal intravenous injections of brain antigens could be replaced by normal peripheral venous infusion, the convenience of immune tolerance treatment could certainly be greatly increased. We attempted to encapsulate brain antigens with minimally immunogenic nanomaterials, to control the sizes of nanoparticles within the range of liver Kupffer cell phagocytosis and to coat the antigens with a coating material that had an affinity for liver cells. We injected these liver drug-loaded nanomaterials via peripheral intravenous injection. With the use of microparticles with liver characteristics, the brain antigens were transported into the liver out of the detection of immune armies in the blood. This approach has been demonstrated in rat models of surgical brain injury. It has been proven that the immune tolerance of brain antigens can be accomplished by peripheral intravenous infusion to achieve the effect of treating brain trauma after operations, which simplifies the clinical operation and could elicit substantial improvements in the future.

Functional Microparticle R&D for IVD and Cell Therapeutic Technology: Large-Scale Commercialized Products

The global R&D of functional materials have become more prominent and are expected to increase with a high growth rate through 2022. High demand due to current and emerging applications, superior structural properties, and the development of advanced fabrication methods is accelerating and driving the functional materials market. The functional materials are segmented based on application into construction composites, medical technology, cosmetics & personal care, oil & gas, automotive, life science & technology, and other categories. In particular, the use of microparticles as functional materials is continually increasing in the field of medicine and the healthcare industry. Nanotechnology for diagnosis, monitoring, drug delivery, treatment and control of biological systems is the leading application in the microparticle market, causing the growing demand for new types of microparticles. Furthermore, growing medical and healthcare industries will increase the worldwide demand for new functional microparticles in biomedical technology applications. This review paper will discuss the main aspects of state-of-the-art functional microparticles research, while demonstrating the broad variety of applications in the fields of diagnostics and therapy, especially in large-scale commercialized products related to magnetic microparticles in IVD and to microcarriers in cell therapeutics.

Paclitaxel delivery system based on poly(lactide-co-glycolide) microparticles and chitosan thermo-sensitive gel for mammary adenocarcinoma treatment.

To evaluate the combination of more than one release system in the same formulation as a useful strategy to achieve paclitaxel delivery in a more sustained and controlled manner. The present study deals with the preparation of poly(lactide-co-glycolide) microparticles loaded with paclitaxel and included in a chitosan thermo-sensitive gelling solution. The microparticles were characterized by their size, shape and drug loading. The formulation was characterized by scanning electron microscopy, in vitro release experiments and was evaluated in mice bearing mammary adenocarcinoma. The formation of paclitaxel crystals in a pharmaceutical formulation reduces its efficacy. In this work, the use of microparticles avoided this phenomenon. Combining more than one delivery system allowed delivering paclitaxel in a more sustained and controlled manner leading to a long-term effect in the site of action. The formulation showed an inhibition in tumour volume of 63.0% in comparison with the control group. One intratumour injection of gelling solution containing the microparticles was at least as efficacious as four intraperitoneal injections of a commercial formulation. In addition, the delivery system was nontoxic, and the treated mice presented the highest percentage of tumour regression and median survival time.

Engineering fungal morphology for enhanced production of hydrolytic enzymes by Aspergillus oryzae SBS50 using microparticles.

Effect of microparticles and silver nanoparticles was studied on the production of hydrolytic enzymes by a potent phytase-producing mould, Aspergillus oryzae SBS50. Addition of microparticles, viz. talc powder and aluminum oxide enhanced phytase production from 2894 to 3903 and 2847 to 4204U/L, cellulase from 2529 to 4931 and 2455 to 3444U/L, xylanase from 9067 to 9642 and 9994 to 14,783U/L, amylase from 5880 to 11,000 and 6130 to 13,145U/L, respectively. Fungal morphology was also engineered by the use of microparticles. Fungal pellet size was significantly reduced (~ 90%) by the addition of microparticles. Fermentation time was reduced from 4 to 3 days after the addition of microparticles, thus increasing the productivity of the enzymes significantly. These results confirmed the importance of microparticles in engineering fungal morphology for enhanced production of hydrolytic enzymes.

Synthesis and characterization of hyaluronic acid coated manganese dioxide microparticles that act as ROS scavengers

Atherosclerosis is a chronic inflammatory disease of the arterial wall that leads to cardiovascular diseases which are the major cause of deaths worldwide. There is currently no treatment that can stop or reverse the disease. However, the use of microparticles with anti-inflammatory properties could represent a promising treatment. Herein, spherical microparticles with a core-shell structure and an average diameter of 1μm were synthesized. The microparticles were comprised of a MnCO3 and MnO2 core and a 4-arm PEG-amine cross-linked shell of hyaluronic acid. The HA-Mn-SM microparticles were loaded with D-α-tocopherol (vitamin-E) (TOC), to fabricate a targeted biocompatible delivery platform for the treatment of atherosclerotic inflamed cells. Loading and release studies of TOC demonstrated a lactic acid concentration dependant controlled release profile of the HA-Mn-SM mimicking the atherosclerotic environment where lactic acid is over-produced. The microparticles exhibited a high scavenging ability towards H2O2 in addition to the controlled generation of O2. The optimal results were obtained for 250μg/mL microparticles which in the presence of 1000μM H2O2 resulted in the scavenging of almost all the H2O2. Our results demonstrate that 50μg/mL of microparticles scavenged continuously produced H2O2 up to a concentration of 1000μM, a characteristic that demonstrates the sustained therapeutic effect of the HA-Mn-SM microparticles in an environment that mimics that of inflamed tissues. Our results indicate the potential use of HA-Mn-SM as a novel platform for the treatment of atherosclerosis. In vitro studies confirmed that the microparticles are not cytotoxic at concentrations up to 250μg/mL and for 72h. These preliminary results indicate the potential use of HA-Mn-SM as a novel drug delivery system for atherosclerotic tissues.

Preservation of Anticancer and Immunosuppressive Properties of Rapamycin Achieved Through Controlled Releasing Particles.

Rapamycin is commonly used in chemotherapy and posttransplantation rejection suppression, where sustained release is preferred. Conventionally, rapamycin has to be administered in excess due to its poor solubility, and this often leads to cytotoxicity and undesirable side effects. In addition, rapamycin has been shown to be hydrolytically unstable, losing its bioactivity within a few hours. The use of drug delivery systems is hypothesized to preserve the bioactivity of rapamycin, while providing controlled release of this otherwise potent drug. This paper reports on the use of microparticles (MP) as a means to tune and sustain the delivery of bioactive rapamycin for up to 30days. Rapamycin was encapsulated (100% efficiency) in poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), or a mixture of both via an emulsion method. The use of different polymer types and mixture was shown to achieve a variety of release kinetics and profile. Released rapamycin was subsequently evaluated against breast cancer cell (MCF-7) and human lymphocyte cell (Jurkat). Inhibition of cell proliferation was in good agreement with in vitro release profiles, which confirmed the intact bioactivity of rapamycin. For Jurkat cells, the suppression of cell growth was proven to be effective up to 20days, a duration significantly longer than free rapamycin. Taken together, these results demonstrate the ability to tune, sustain, and preserve the bioactivity of rapamycin using MP formulations. The sustained delivery of rapamycin could lead to better therapeutic effects than bolus dosage, at the same time improving patient compliance due to its long-acting duration.