The development of novel materials and approaches for effective energy consumption and the employment of renewable energy sources is one of the current trends in modern material science. With this ...respect, the number of researches is focused on the effective harvesting and storage of solar energy for various applications. Phase change materials (PCMs) are known to be able to store thermal energy of the sunlight due to adsorption and release of latent heat through reversible phase transitions. Therefore, PCMs are promising as functional additives to construction materials and paints for advanced thermoregulation in building and industry. However, bare PCMs have limited practical applications. Organic PCMs like paraffins suffer from material leakage when undergoing in a liquid state while inorganic ones like salt hydrates lack long-term stability after multiple phase transitions. To avoid this, the loading of PCMs in porous matrices are intensively studied along with the thermal properties of the resulted composites. The loading of PCMs in microcontainers of natural porous or layered clay materials appears as a simple and cost-effective method of encapsulation significantly improving the shape and cyclic stability of PCMs. Additionally, the inclusion of functional clay containers into construction materials allows for improving their mechanical and flame-retardant properties. This article summarizes the recent progress in the preparation of composites based on PCM-loaded clay microcontainers along with their future perspectives as functional additives in thermo-regulating materials.
Flow cytometry nowadays is among the main working instruments in modern biology paving the way for clinics to provide early, quick, and reliable diagnostics of many blood-related diseases. The major ...problem for clinical applications is the detection of rare pathogenic objects in patient blood. These objects can be circulating tumor cells, very rare during the early stages of cancer development, various microorganisms and parasites in the blood during acute blood infections. All of these rare diagnostic objects can be detected and identified very rapidly to save a patient's life. This review outlines the main techniques of visualization of rare objects in the blood flow, methods for extraction of such objects from the blood flow for further investigations and new approaches to identify the objects automatically with the modern deep learning methods.
The increased research activity aiming at improved delivery of pharmaceutical molecules indicates the expansion of the field. An efficient therapeutic delivery approach is based on the optimal choice ...of drug-carrying vehicle, successful targeting, and payload release enabling the site-specific accumulation of the therapeutic molecules. However, designing the formulation endowed with the targeting properties in vitro does not guarantee its selective delivery in vivo. The various biological barriers that the carrier encounters upon intravascular administration should be adequately addressed in its overall design to reduce the off-target effects and unwanted toxicity in vivo and thereby enhance the therapeutic efficacy of the payload. Here, we discuss the main parameters of remote-controlled drug delivery systems: (i) key principles of the carrier selection; (ii) the most significant physiological barriers and limitations associated with the drug delivery; (iii) major concepts for its targeting and cargo release stimulation by external stimuli in vivo. The clinical translation for drug delivery systems is also described along with the main challenges, key parameters, and examples of successfully translated drug delivery platforms. The essential steps on the way from drug delivery system design to clinical trials are summarized, arranged, and discussed.
Remote navigation and targeted delivery of biologically active compounds is one of the current challenges in the development of drug delivery systems. Modern methods of micro- and nanofabrication ...give us new opportunities to produce particles and capsules bearing cargo to deploy and possess magnetic properties to be externally navigated. In this work we explore multilayer composite magnetic microcapsules as targeted delivery systems in vitro and in vivo studies under natural conditions of living organism. Herein, we demonstrate magnetic addressing of fluorescent composite microcapsules with embedded magnetite nanoparticles in blood flow environment. First, the visualization and capture of the capsules at the defined blood flow by the magnetic field are shown in vitro in an artificial glass capillary employing a wide-field fluorescence microscope. Afterward, the capsules are visualized and successfully trapped in vivo into externally exposed rat mesentery microvessels. Histological analysis shows that capsules infiltrate small mesenteric vessels whereas large vessels preserve the blood microcirculation. The effect of the magnetic field on capsule preferential localization in bifurcation areas of vasculature, including capsule retention at the site once external magnet is switched off is discussed. The research outcome demonstrates that microcapsules can be effectively addressed in a blood flow, which makes them a promising delivery system with remote navigation by the magnetic field.
•MFC was modified with Ag nanoparticles with a mass content of 13%•Adsorption of SA onto AgMFC fibers results in shape stable PCM composites.•Ag nanoparticles do not affect the phase transitions of ...SA on the fiber surface.•SA/AgMFC composites have improved heating and cooling rate comparing to SA/MFC ones.•The improved heat transfer in SA/AgMFC composites reduces their thermal stability.
Composite phase change material was prepared via adsorption of stearic acid onto cellulose microfibrils modified with Ag nanoparticles. The latent heat storage capacity, cycling performance, thermal stability, and heating/cooling rate of the composites were studied with differential scanning calorimetry, thermogravimetric analysis, and thermal imaging and compared to those of the composite prepared by adsorption of stearic acid onto pure microfibrillar cellulose. The modification of cellulose with Ag nanoparticles improves the heating and cooling rate of the composites and promotes latent heat release during the solidification of stearic acid on the fiber surface.
We demonstrate a novel approach to the controlled loading of inorganic nanoparticles and proteins into submicron- and micron-sized porous particles. The approach is based on freezing/thawing cycles, ...which lead to high loading densities. The process was tested for the inclusion of Au, magnetite nanoparticles, and bovine serum albumin in biocompatible vaterite carriers of micron and submicron sizes. The amounts of loaded nanoparticles or substances were adjusted by the number of freezing/thawing cycles. Our method afforded at least a three times higher loading of magnetite nanoparticles and a four times higher loading of protein for micron vaterite particles, in comparison with conventional methods such as adsorption and coprecipitation. The capsules loaded with magnetite nanoparticles by the freezing-induced loading method moved faster in a magnetic field gradient than did the capsules loaded by adsorption or coprecipitation. Our approach allows the preparation of multicomponent nanocomposite materials with designed properties such as remote control (e.g. via the application of an electromagnetic or acoustic field) and cargo unloading. Such materials could be used as multimodal contrast agents, drug delivery systems, and sensors.
Organic phase-change materials (PCMs) hold promise in developing advanced thermoregulation and responsive energy systems owing to their high latent heat capacity and thermal reliability. However, ...organic PCMs are prone to leakages in the liquid state and, thus, are hardly applicable in their pristine form. Herein, we encapsulated organic PCM n-Octadecane into polyurethane capsules via polymerization of commercially available polymethylene polyphenylene isocyanate and polyethylene glycol at the interface oil-in-water emulsion and studied how various n-Octadecane feeding affected the shell formation, capsule structure, and latent heat storage properties. The successful shell polymerization and encapsulation of n-Octadecane dissolved in the oil core was verified by confocal microscopy and Fourier-transform infrared spectroscopy. The mean capsule size varied from 9.4 to 16.7 µm while the shell was found to reduce in thickness from 460 to 220 nm as the n-Octadecane feeding increased. Conversely, the latent heat storage capacity increased from 50 to 132 J/g corresponding to the growth in actual n-Octadecane content from 25% to 67% as revealed by differential scanning calorimetry. The actual n-Octadecane content increased non-linearly along with the n-Octadecane feeding and reached a plateau at 66–67% corresponded to 3.44–3.69 core-to-monomer ratio. Finally, the capsules with the reasonable combination of structural and thermal properties were evaluated as a thermoregulating additive to a commercially available paint.
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•Freezing induced loading and Layer by Layer methods were used for capsule preparation.•The release of Cy7 labeled BSA initially quenched by magnetite was shown in vivo.•The decrease ...of Cy7 fluorescence after HIFU due to reactive oxygen species was observed.•Fast time- and site-specific release of Cy7-BSA in vivo under HIFU was demonstrated.
High intensity focused ultrasound (HIFU) is widely used in medical practice, including cancer therapy. Also this approach is promising for remote release of encapsulated drugs in various other biomedical applications where local treatment is needed. Our approach underpins the minimization of HIFU impact on possible degradation of biological tissues and expand the use of HIFU in the controlled release of encapsulated drugs. We demonstrated the efficient ultrasound-induced release of labeled protein (Cy7-BSA) from elaborated nanocomposite microcapsules in vitro an in vivo. The capsule fabrication was done using combination of recently developed freezing-induced loading (FIL) technique and Layer-by-Layer assembly (LbL) used for the preparation of complex multilayer BSA/tannic acid nanocomposite capsules sensitive to HIFU. These capsules contain NIR fluorescent Cy7-labeled BSA in the shell for tracking in vivo and the high concentration of labels inside the capsules resulted in self-quenching provides the real-time detection of the protein once it is released from the capsule. Ultrasound-induced release in vivo of Cy7-labeled BSA initially quenched by magnetite nanoparticles was confirmed by fluorescent tomography. The significant decrease of Cy7 fluorescence under HIFU treatment in vitro was found to be due to a generation of reactive oxygen species and fast dye oxidation. Our results demonstrate that adapted HIFU setup can be used for the directed release of encapsulated substances in vivo under tissue compatible NIR monitoring by fluorescent tomography.
•Halloysites (HNTs) are suitable containers for freezing-induced loading (FIL).•FIL of AuNPs into HNTs has an efficiency of 85% after 5 loading cycles.•FIL is twice efficient than vacuum impregnation ...and adsorption from solution.•FIL efficiency may be improved by adjusting the size and concentration of NPs.
Au nanoparticles were loaded into halloysite nanotubes by freezing-induced loading method. The loading efficiency and Au nanoparticle distribution were studied by UV–Vis absorption spectroscopy and transmission electron microscopy and compared to those of vacuum impregnation and adsorption from solution loading methods. The freezing-induced loading was found to be the most effective with the loading efficiency up to 85% after 5 loading cycles and the best Au nanoparticle distribution into halloysite nanotubes.
Adsorption of organic phase-change materials (PCMs) by the porous matrix of microfibrillar cellulose (MFC) is a simple and versatile way to prepare shape-stable phase-change composites, which are ...promising as sustainable thermoregulating additives to construction materials. However, due to MFC inherent morphology, the resulting composites have relatively low poured density that complicates their introduction in sufficient amounts, for instance, into mortar mixes. Unlike MFC, fungal mycelium has, by an order, less fibrils thickness and, thus, possesses significantly higher poured density. Herein, we studied the feasibility of fungal mycelium-based matrices as alternative biopolymeric porous supports for preparation of sustainable and shape-stable phase-change composites. Two methods were employed to prepare the porous mycelium-based supports. The first one was the solid-state fermentation, which resulted in partial biotransformation of MFCs to mycelium hyphae, while the second one was the liquid-state surface fermentation, used to cultivate the reference matrix of
hyphae. The phase-change composites were prepared by adsorption of model organic PCMs on porous biopolymer matrices. The mass ratio of support/PCM was 40/60 wt%. The composites were studied with respect to their structure, composition, poured density, latent heat storage properties, and thermal and shape stability. The employment of the partially transformed to mycelium-hyphae MFC fibers was found to be a suitable way to prepare phase-change composites with improved poured density while preserving a reasonable latent heat capacity and shape stability as compared to the MFC/PCM composites.
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