The balance of alveolar macrophage (AM) polarization is severely disrupted in chronic inflammatory diseases like bronchiectasis, where a persistent pro-inflammatory (M1) phenotype perpetuates inflammation. To address this, we developed a high-throughput platform using a series of synthetic glycoligands (L1-L5) on a polyethyleneimine (PEI) scaffold. These ligands, which have varying affinities for macrophage lectin-like receptors, were used for phenotypic “fingerprinting” of AM subpopulations from pediatric bronchiectasis patients and a healthy control. Analysis of bronchoalveolar lavage fluid (BALF) revealed a pathogenic, M1-dominant profile (55% M1) in patients, confirming a state of chronic inflammation, which starkly contrasted with the quiescent, M0-dominant profile in the healthy control. We then leveraged this platform for targeted immunomodulation, using a drug-ligand conjugate to steer the dysregulated macrophage population toward a healthy state. The most potent conjugate, Dox-L5, dramatically suppressed the pathogenic M1 population (from 55% to 16%). This M1 suppression was accompanied by a significant shift toward the M2a (tissue-repair) phenotype and the emergence of a quiescent M0-like population, effectively remodeling the AM profile. This work validates a glycan-based platform for both diagnosing and correcting pathological macrophage imbalances. Our targeted approach offers a precise strategy to resolve chronic inflammation in bronchiectasis by suppressing M1 macrophages and promoting a pro-resolving M0/M2 phenotype, thereby restoring lung homeostasis.

Macrophage (Mph) polarization and functional activity play an important role in the development of inflammatory lung conditions. The previously widely used bimodal classification of Mph into M1 and M2 does not adequately reflect the full range of changes in polarization and functional diversity observed in Mph in response to various stimuli and disease states. Here, we have developed a model for the direct assessment of Mph from bronchial alveolar lavage fluid (BALF) functional alterations, in terms of phagocytosis activity, depending on external stimuli, such as exposure to a range of bacteria (E. coli, B. subtilis and L. fermentum). We have employed polymeric mannosylated ligands (the “trapping ligand”) specifically targeting the CD206 receptor to selectively isolate activated Mph from the BALF of patients with pulmonary inflammatory conditions: primary ciliary dyskinesia (PCD), pneumonia and bronchial asthma. An “imaging ligand” allows for the subsequent visualization of the isolated cells using a sandwich technique. Five model strains of E. coli, MH-1, JM109, BL21, W3110 and ATCC25922, as well as B. subtilis and L. fermentum strains, each exhibiting distinct properties and expressing red fluorescent protein (RFP), were used as a phagocytosis substrate. Fluorometric, FTIR- and confocal laser scanning microscopy (CLSM) assessments of the phagocytic response of Mph to these bacterial cells were performed. Mph absorbed different strains of E. coli with different activities due to the difference in the surface villosity of bacterial cells (pili and fimbriae, as well as signal patterns). In the presence of other competitor cells (like those of Lactobacilli), the phagocytic activity of Mph is changed between two and five times and strongly dependent on the bacterial strain. The relative phagocytic activity indexes obtained for BALF-Mph in comparison with that obtained for model human CD206+ Mph in the M1 polarization state (derived from THP-1 monocyte cultures) were considered as a set of parameters to define the Mph polarization profile from the BALF of patients. Mannan as a marker determining the selectivity of the binding to the CD 206 mannose receptor of Mph significantly inhibited the phagocytosis of E. coli and B. subtilis in cases of pneumonia, suggesting an important role of CD206 overexpression in acute inflammation. Conversely, L. fermentum binding was enhanced in PCD, possibly reflecting altered macrophage responsiveness in chronic lung diseases. Our approach based on the profiling of Mph from patient BALF samples in terms of phagocytosis for a range of model bacterial strains is important for the subsequent detailed study of the factors determining dangerous conditions and resistance to existing therapeutic options.

Bilayer opal-type stripes periodically arranged on the same substrate were self-assembled using the vertical deposition of SiO2 spheres with the intermittent motion of the meniscus. It has been shown that each such stripe with a gold or silver coating can be considered as an independent element for surface enhanced Raman scattering (SERS). The thicknesses of the gold and silver coatings were optimized using computer simulations of electromagnetic field enhancement. Monolayer or bilayer stripes of such type are not inferior to thick opal films with noble metal coating. The stripe patterned structures are easy to manufacture, exhibit good homogeneity and may be promising for automating multiple SERS tests. The structures with gold coating also demonstrate high resistance to environmental influences. The prospects for further improvement of their properties were analyzed.

L-asparaginase (L-ASNase) is a vital enzymatic drug widely used for treating acute lymphoblastic leukemia (ALL) and certain lymphomas. However, its clinical application is often limited by a short plasma half-life, pronounced immunogenicity, and systemic toxicities. To address these challenges, we recently developed conjugates of L-ASNase with cationic polymers, enhancing its cytostatic activity by increasing enzyme binding with cancer cells. The present study focuses on the development of liposomal formulations of E. coli L-asparaginase (EcA) and its conjugates with cationic polymers: the natural oligoamine spermine (spm) and a synthetic polyethylenimine–polyethyleneglycol (PEI-PEG) copolymer. This approach aims to improve enzyme encapsulation efficiency and stability within liposomes. Various formulations—including EcA conjugates with polycations incorporated into 100 nm and 400 nm phosphatidylcholine/cardiolipin (PC/CL, 80/20) anionic liposomes—were synthesized as a delivery system of high enzyme load. Fourier Transform Infrared (FTIR) spectroscopy confirmed successful enzyme association with liposomal carriers by identifying characteristic changes in the vibrational bands corresponding to both protein and lipid components. In vitro release studies demonstrated that encapsulating EcA formulations in liposomes more than doubled their half-release time (T1/2), depending on the formulation. Cytotoxicity assays against Raji lymphoma cells revealed that liposomal formulations, particularly 100 nm EcA-spm liposomes, exhibited markedly superior anti-proliferative activity, reducing cell viability to 4.5%, compared to 35% for free EcA. Confocal Laser Scanning Microscopy (CLSM) provided clear visual and quantitative evidence that enhanced cellular internalization of the enzyme correlates directly with its cytostatic efficacy. Notably, formulations showing higher intracellular uptake produced greater cytotoxic effects, emphasizing that hydrolysis of asparagine inside cancer cells, rather than extracellularly, is critical for therapeutic success. Among all tested formulations, the EcA-spermine liposomal conjugate demonstrated the highest fluorescence intensity within cells providing enhanced cytotoxicity. These results strongly indicate that encapsulating cationically modified L-ASNase in liposomes is a highly promising strategy to improve targeted cellular delivery and prolonged enzymatic activity. This strategy holds significant potential for developing more effective and safer antileukemic therapies.

L-asparaginase (L-ASNase) remains a vital chemotherapeutic agent for acute lymphoblastic leukemia (ALL), primarily due to its mechanism of depleting circulating asparagine essential for leukemic cell proliferation. However, existing ASNases (including pegylated ones) face limitations including immunogenicity, rapid clearance, and off-target toxicities. Earlier, we have shown that the conjugation of L-ASNase with the polyamines and their copolymers results in significant enhancement of the antiproliferative activity due to accumulation in tumor cells. We suggested that this effect is probably mediated by polyamine transport system (PTS) receptors that are overexpressed in ALL cells. Here, we investigated the effect of competitive inhibitors of PTS receptors to the L-ASNase interaction with cancer cells (L5178Y, K562 and A549). L-ASNase from Rhodospirillum rubrum (RrA), Erwinia carotovora (EwA), and Escherichia coli (EcA) were conjugated with natural polyamines (spermine—spm, spermidine—spd, putrescine—put) and a synthetic branched polymer, polyethyleneimine 2 kDa (PEI2 ), using carbodiimide chemistry. Polyamine conjugation with L-ASNase significantly increased enzyme binding and cellular uptake, as quantified by fluorimetry and confocal microscopy. This increased cellular uptake translated into increased cytotoxicity of L-ASNase conjugates. The presence of competitive ligands to PTS receptors decreased the uptake of polyamine-conjugated enzymes-fatty acid derivatives of polyamines produced the strongest suppression. Simultaneously with this suppression, in some cases, competitive ligands to PTS significantly promoted the uptake of the native unconjugated enzymes, “equalizing” the cellular access for native vs conjugated ASNase. The screening for competing inhibitors of PTS receptor-mediated endocytosis revealed spermine and caproate/lipoate derivatives as the most potent inhibitors or antagonists, significantly reducing the cytostatic efficacy of polyamine-conjugated ASNases. The results obtained emphasize the complex, cell-type-dependent and inhibitor-specific nature of these interactions, which highlights the profound involvement of PTS in L-ASNase internalization and cytotoxic activity. These findings support the viability of polyamine conjugation as a strategy to enhance L-ASNase delivery and therapeutic efficacy by targeting the PTS.

As shown previously, Rhodamine 6G (R6G) and 4-nitro-2,1,3-benzoxadiazole (NBD) linked through a spacer molecule spermidine (spd), R6G-spd-NBD, produce a fluorescent probe with pH-sensitive FRET effect, that can be useful in a variety of diagnostic applications. Specifically, cancer cells can be spotted due to a local decrease in pH (Warburg effect). Here we extend this approach to infectious diseases – namely, leishmaniasis, brucellosis, and tuberculosis, are difficult to treat largely because of their localization inside macrophages. R6G-spd-NBD offers an opportunity to detect such bacteria and potentially deliver therapeutic target to treat them. The micellar form of the R6G-spd-NBD probe (chitosan or heparin grafted with lipoic acid residues, Chit-LA and Hep-LA, respectively) was obtained to improve the pH sensitivity in the desired range (5.5–7.5) and enable the selective targeting of bacterial cells, thus improving CLSM imaging. According to AFM (atomic force microscopy) data, the micelles containing NBD-spd-R6G have a compact and highly spherical shape, with a diameter ranging from 70 to 110 nm. The micellar form of the R6G-spd-NBD further improves absorption and penetration into bacteria, including those located inside macrophages. Due to negative charge of the surface, bacteria absorb positively charged R6G-spd-NBD, and even more so in the micellar form, when chitosan derivatives are used to form the polymeric micelle. Additionally, macrophages’ lysosomes can be easily distinguished due to their acidic pH. Confocal laser scanning microscopy was used to visualize samples of macrophages cells containing absorbed bacteria. The micellar formulation showed a significant selectivity to model E. coli vs Lactobacillus bacterial cells, and R6G-spd-NBD, being a mild bactericide, clears over 50% E.coli in conditions where Lactobacillus remains almost unaffected. Taken together, our data indicates that R6G-spd-NBD, as well as similar compounds, can have value not only for diagnostic, but also for theranostic applications.

We have developed a micellar formulation of anticancer drugs based on chitosan and heparin grafted with lipoic and oleic acids that can release the cytotoxic cargo (doxorubicin) in response to external stimuli, such as increased glutathione concentration—a hallmark of cancer. Natural polysaccharides (heparin and chitosan) provide the pH sensitivity of the nanocarrier: the release of doxorubicin (Dox) is enhanced in a slightly acidic environment (tumor microenvironment). Fatty acid residues are necessary for the formation of nanoparticles (micelles) and solubilization of cytostatics in a hydrophobic core. Lipoic acid residues provide the formation of a labile S-S cross-linking between polymer chains (the first variant) or covalently attached doxorubicin molecules through glutathione-sensitive S-S bridges (the second variant)—both determine Redox sensitivity of the anticancer drugs carriers stable in blood circulation and disintegrate after intracellular uptake in the tumor cells. The release of doxorubicin from micelles occurs slowly (20%/6 h) in an environment with a pH of 7.4 and the absence of glutathione, while in a slightly acidic environment and in the presence of 10 mM glutathione, the rate increases up to 6 times, with an increase in the effective concentration up to 5 times after 7 h. The permeability of doxorubicin in micellar formulations (covalent S-S cross-linked and not) into Raji, K562, and A875 cancer cells was studied using FTIR, fluorescence spectroscopy and confocal laser scanning microscopy (CLSM). We have shown dramatically improved accumulation, decreased efflux, and increased cytotoxicity compared to doxorubicin control with three tumor cell lines: Raji, K562, and A875. At the same time, cytotoxicity and permeability for non-tumor cells (HEK293T) are significantly lower, increasing the selectivity index against tumor cells by several times.

Currently, the most promising work seems to be aimed not so much at the development of new drugs, but rather at creating ways of targeted delivery of existing drugs. In this paper, we show that polymeric micelles based on chitosan, heparin grafted with lipoic and oleic acids residues demonstrate the potential for doxorubicin delivery to tumors due to pH-, glutathione-sensitivity. Smart delivery systems use the Aikido principle, i.e. they target tumor cells according to their features. Natural polysaccharides (heparin and chitosan) provide the pH sensitivity of micelles: the release of doxorubicin (Dox) is enhanced in a slightly acidic environment (model tumor microenvironment). Fatty acid residues are necessary for the formation of micelles and solubilization of cytostatics in a hydrophobic core. Lipoic acid residues formed a labile S-S cross-linking between polymer chains (the first method), and also covalently attached doxorubicin molecules through glutathione-sensitive S-S bridges (the second option) – determine Redox sensitivity of micelles to tumors. The characterization of polymeric micelles and prodrugs (Dox-polymer) was carried out using FTIR spectroscopy. The release of doxorubicin from micelles occurs slowly (20% / 6h) in an environment with a pH of 7.4 and the absence of glutathione, while in a slightly acidic environment and in the presence of 10 mM glutathione, the rate increases up 6 times, with an increase in the effective concentration up to 5 times after 7 h. The permeability of free doxorubicin, micellar formulations (covalent S-S crosslinked and not) into Raji, K562, A875 cancer cells was studied using confocal laser scanning microscopy (CLSM), demonstrated an increase in the permeability of micellar formulations based on Dox. Thus, we have presented micellar formulations of doxorubicin for targeted delivery to tumor, what is important in the aspects of reducing non-target toxicity, increasing the selectivity of cytostatics against tumors and overcome multidrug resistance.

Herein, we propose an analytical approach based on intermolecular fluorescent resonant energy transfer (FRET) pairs for the visualization of specific enzyme activity in model biomembranes and in living cells. Cell visualizations with fluorescent confocal laser microscopy usually rely on fluorescent probes, such as Fluorescein isothiocyanate (FITC), Alexa488, Tetramethylrhodamine isothiocyanate (TRITC) and many others. However, for more specific tasks, such as the detection of certain enzymatic activity inside the living cell, the toolbox is quite limited. In the case of enzyme-hydrolases for example, the choice is limited to organic molecules comprising a fluorescent dye (typically, 4-methylumbelliferone (MUmb) or 7-amino-4-methylcoumarin (AMC) derivatives) and a fluorescence quencher, bound via an enzyme-sensitive linker—so that when the linker is degraded, the fluorescent signal increases. Unfortunately, both MUmb and AMC are quenched and have a relatively low quantum yield in cells, and their excitation and emission ranges overlap with that of intracellular fluorophores, often producing a strong background noise. R6G, on the other hand, has excellent quantum yield apart from intracellular fluorophores, but there are no efficient quenchers that could be chemically linked to R6G. Herein, we show that R6G is able to form intermolecular FRET pairs with MUmb or AMC, with the latter serving as fluorescence donors. This yields a combination of R6G’s excellent fluorescence properties with a possibility to use an enzyme-sensitive linker in MUTMAC or AMC derivatives. This phenomenon was initially discovered in a model system, reversed micelles, where the donor, the acceptor, and the enzyme are forced to be in close proximity to each other, so that proximity could serve as an explanation for the intermolecular FRET effect. Surprisingly enough, the phenomenon has been reproduced in living cells. Moreover, we were able to create working intermolecular donor–acceptor FRET pairs for several different enzymes, including chymotrypsin, phosphatase, and asparaginase. This appears counterintuitive, as besides the overlap of the emission spectra of the donor and the absorption spectra of the acceptor, there are other criteria for the FRET effect, including the convergence of two fluorophores at a distance of about 1–10 nm, and the orientation of their dipoles at a certain angle, which is difficult to imagine in a bulk system like a living cell. We hypothesize that FRET-enabling donor–acceptor interaction may be taking place at the inner surface of the lipid bilayer, to which both donor and acceptor molecules would likely have an affinity. This hypothesis would require a more detailed investigation. Therefore, we have shown that the method suggested has good potential in the visualization of enzyme functioning inside living cells, which is often a challenging task. Shifting of the fluorescence signal to the long-wavelength region would increase the signal selectivity, making it easily distinguishable from autofluorescence.

Polycrystalline films of organic–inorganic perovskite semiconductors are promising as a base for designing functional optical metasurfaces. The requirements to their structural quality, thickness uniformity, homogeneity, and absence of defects are much more stringent than those for perovskite films used in photovoltaics. The results of searching for the optimal conditions of one-stage synthesis of methylammonium-lead bromide films by spin coating are reported, and successful preparation of subwavelength optical gratings based on them using focused ion beam (FIB) processing is described. The measured light transmission spectra demonstrated excellent optical quality of the gratings and confirmed the possibility of forming semiconductor photonic metasurfaces with submicron periodicity and high-Q dielectric resonances.

There are several well-known methods for determining enzyme catalytic activity, including spectral techniques and electrochemical approaches. However, at present, there is no definitive solution to the challenges associated with the fluorescent approach in, for instance, systems of reverse micelles, non-aqueous media, and model biomembranes. We propose the use of the fluorescent resonant energy transfer (FRET) technique, which can enhance the selectivity of fluorescent detection of enzyme activity by shifting the maximum emission wavelength to the longer-wavelength range and reducion the influence of medium components. As fluorescence donors, we have used derivatives of 4-methylumbelliferone (MUmb) and 7-amino-4-methylcoumarin (AMC), which also serve as substrates for hydrolases such as chymotrypsin, phosphatase, and asparaginase. During the catalytic depletion of substrates, an accumulation of a highly fluorescent product is observed. This product can be specifically detected using the fluorescent marker rhodamine 6G (R6G), which emits light in the red region of the spectrum (550–600 nm) with high quantum yield. A significant FRET effect is observed when forming AOT reverse micelles. This is due to the proximity of fluorophores within the hydrophobic core of the micelle, which is shorter than in a buffer solution. This approach have practical implications for visualizing intracellular processes. The FRET technique can be used to determine intracellular enzymatic activity by detection with confocal laser scanning microcopy (CLSM), as demonstrated with L-asparaginase, a clinically important anti-leukemia medication. The approach suggested will allow researchers to study enzyme activity within cells. This has the potential to revolutionize medicine by improving drug development and shedding light on previously unknown aspects of cellular metabolism.

Rhodamine 6G (R6G) and 4-nitro-2,1,3-benzoxadiazole (NBD) linked through a spacer molecule spermidine (spd), R6G-spd-NBD, produces a fluorescent probe with pH-sensitive FRET (Förster (fluorescence) resonance energy transfer) effect that can be useful in a variety of diagnostic applications. Specifically, cancer cells can be spotted due to a local decrease in pH (Warburg effect). In this research, we applied this approach to intracellular infectious diseases—namely, leishmaniasis, brucellosis, and tuberculosis, difficult to treat because of their localization inside macrophages. R6G-spd-NBD offers an opportunity to detect such bacteria and potentially deliver therapeutic targets to treat them. The nanogel formulation of the R6G-spd-NBD probe (nanoparticles based on chitosan or heparin grafted with lipoic acid residues, Chit-LA and Hep-LA) was obtained to improve the pH sensitivity in the desired pH range (5.5–7.5), providing selective visualization and targeting of bacterial cells, thereby enhancing the capabilities of CLSM (confocal laser scanning microscopy) imaging. According to AFM (atomic force microscopy) data, nanogel particles containing R6G-spd-NBD of compact structure and spherical shape are formed, with a diameter of 70–100 nm. The nanogel formulation of the R6G-spd-NBD further improves absorption and penetration into bacteria, including those located inside macrophages. Due to the negative charge of the bacteria surface, the absorption of positively charged R6G-spd-NBD, and even more so in the chitosan derivatives’ nanogel particles, is pronounced. Additionally, with a pH-sensitive R6G-spd-NBD fluorescent probe, the macrophages’ lysosomes can be easily distinguished due to their acidic pH environment. CLSM was used to visualize samples of macrophage cells containing absorbed bacteria. The created nanoparticles showed a significant selectivity to model E. coli vs. Lactobacillus bacterial cells, and the R6G-spd-NBD agent, being a mild bactericide, cleared over 50% E.coli in conditions where Lactobacillus remained almost unaffected. Taken together, our data indicate that R6G-spd-NBD, as well as similar compounds, can have value not only for diagnostic, but also for theranostic applications.

Cancer cells are known to create an acidic microenvironment (the Warburg effect). At the same time, fluorescent dyes can be sensitive to pH, showing a sharp increase or decrease in fluorescence depending on pH. However, modern applications, such as confocal laser scanning microscopy (CLSM), set additional requirements for such fluorescent markers to be of practical use, namely, high quantum yield, low bleaching, minimal quenching in the cell environment, and minimal overlap with auto-fluorophores. R6G could be the perfect match for these requirements, but its fluorescence is not pH-dependent. We have attempted to develop an R6G conjugate with its FRET or PeT pair that would grant it pH sensitivity in the desired range (5.5–7.5) and enable the selective targeting of tumor cells, thus improving CLSM imaging. Covalent conjugation of R6G with NBD using a spermidine (spd) linker produced a pH-sensitive FRET effect but within the pH range of 7.0–9.0. Shifting this effect to the target pH range of 5.5–7.5 appeared possible by incorporating the R6G-spd-NBD conjugate within a “smart” polymeric micelle based on chitosan grafted with lipoic acid. In our previous studies, one could conclude that the polycationic properties of chitosan could make this pH shift possible. As a result, the micellar form of the NBD-spd-R6G fluorophore demonstrates a sharp ignition of fluorescence by 40%per1 pH unit in the pH range from 7.5 to 5. Additionally, “smart” polymeric micelles based on chitosan allow the label to selectively target tumor cells. Due to the pH sensitivity of the fluorophore NBD-spd-R6G and the selective targeting of cancer cells, the efficient visualization of A875 and K562 cells was achieved. CLSM imaging showed that the dye actively penetrates cancer cells (A875 and K562), while minimal accumulation and low fluorophore emission are observed in normal cells (HEK293T). It is noteworthy that by using “smart” polymeric micelles based on polyelectrolytes of different charges and structures, we create the possibility of regulating the pH dependence of the fluorescence in the desired interval, which means that these “smart” polymeric micelles can be applied to the visualization of a variety of cell types, organelles, and other structures.

Oncological diseases are difficult to treat even with strong drugs due to development the multidrug resistance (MDR) of cancer cells. A strategy is proposed to increase the efficiency and selectivity of cytotoxic agents against cancer cells to engage the differences in the morphology and microenvironment of tumor and healthy cells, including the pH, membrane permeability, and ion channels. Using this approach, we managed to develop enhanced formulations of cytotoxic agents with adjuvants (which are known as efflux inhibitors and as ion channel inhibitors in tumors)—with increased permeability in A549 and a protective effect on healthy HEK293T cells. The composition of the formulation is as follows: cytotoxic agents (doxorubicin (Dox), paclitaxel (Pac), cisplatin) + adjuvants (allylbenzenes and terpenoids) in the form of inclusion complexes with β–cyclodextrin. Modified cyclodextrins make it possible to obtain soluble forms of pure substances of the allylbenzene and terpenoid series and increase the solubility of cytotoxic agents. A comprehensive approach based on three methods for studying the interaction of drugs with cells is proposed: MTT test—quantitative identification of surviving cells; FTIR spectroscopy—providing information on the molecular mechanisms inaccessible to study by any other methods (including binding to DNA, surface proteins, or lipid membrane); confocal microscopy for the visualization of observed effects of Dox accumulation in cancer or healthy cells depending on the drug formulation as a direct control of the correctness of interpretation of the results obtained by the two other methods. We found that eugenol (EG) and apiol increase the intracellular concentration of cytostatic in A549 cells by 2–4 times and maintain it for a long time. However, an important aspect is the selectivity of the enhancing effect of adjuvants on tumor cells in relation to healthy ones. Therefore, the authors focused on adjuvant’s effect on the control healthy cells (HEK293T): EG and apiol demonstrate “protective” properties from cytostatic penetration by reducing intracellular concentrations by about 2–3 times. Thus, a combined formulation of cytostatic drugs has been found, showing promise in the aspects of improving the efficiency and selectivity of antitumor drugs; thereby, one of the perspective directions for overcoming MDR is suggested.

Thin film ferromagnet/antiferromagnet (F/AF) exchange biased structures that are widely used in GMR spin valves are considered nowadays as promising systems for antiferromagnetic spintronic and spin-orbitronic devices. Here, the temperature dependences of magnetization dynamics in Co/IrMn and Co/FeMn F/AF structures are investigated using ferromagnetic resonance (FMR) in comparison to a free Co layer. A strong additional decrease in the resonance field was observed in Co/IrMn with a temperature decrease attributed to the rotatable anisotropy increase, which almost vanished at room temperature. In contrast to Co/IrMn, the contribution of the rotatable anisotropy in Co/FeMn is much weaker, even though it exists at RT, it is negative, and slightly varies with the temperature and resonance field shift in Co/FeMn. This is mainly due to unidirectional exchange anisotropy. FMR linewidth for the free Co layer increases with decreasing temperature and is accompanied with a slow relaxation process, while the additional contribution to FMR line broadening in Co/IrMn and Co/FeMn structures is correlated with variation in the exchange anisotropy. The observed results are discussed based on structural and surface morphology and magnetization reversal characterization using X-ray diffraction, atomic force microscopy, and vibrating sample magnetometry data.

Lamellar and hexagonal pattern rearrangements in thin films of polystyrene-block-poly(2-vinyl pyridine) and polystyrene-block-poly(4-vinyl pyridine) copolymers simultaneously exposed to an in-plane AC electric field and saturated chloroform vapor are studied with atomic force microscopy and analyzed via the numerical solution of the self-consistent field theory equations. It is demonstrated that the use of AC field with the root-mean-square strength higher than 8 V center dot mu m(-1) allows one to effectively orient microphase-separated domains along the field direction on the tens of microns scale. At the same time, the AC field considerably lowers the risk of breakdown and eliminates effects related to ionic transport in the presence of solvent vapor. The role of such factors as the exposure time, field strength and frequency is investigated. Theoretical considerations prove the equivalent effect of AC and DC fields on the structure of the copolymer film in a wide frequency range. Self-consistent field theory calculations of the free energy as a function of film thickness make it possible to exactly identify which phase dominates in the film. In particular, an apparent transformation of standing cylinders into long threads aligned in the field direction should be interpreted as the phase transition from the perpendicular to parallel hexagonal phase, which can take place in a certain range of film thicknesses, provided the electric field strength exceeds a certain threshold value. In the case of a perpendicular lamellar phase, the domain orientation along the direction of the electric field is always profitable. The observed morphological rearrangements under an in-plane field, which preserve connectivity between the film surfaces through the domains of the minor copolymer block, can be important for practical applications.

The main factors that determine the low effectiveness of chemotherapy are the low target bioavailability of antitumor drugs and the efflux process. In attempts to overcome this problem, several approaches are proposed here. Firstly, the development of polymeric micellar systems based on chitosan grafted by fatty acids (different types to optimize their properties), which, on the one hand, increase the solubility and bioavailability of cytostatics and, on the other hand, effectively interact with tumor cells due to the polycationic properties of chitosan, allowing for more effective penetration of cytostatic drugs into the cells. Secondly, the use of adjuvants—synergists of cytostatics (such as eugenol) included in the same micellar formulation—that selectively enhance the accumulation and retention of cytostatics in the tumor cells. pH- and temperature-sensitive polymeric micelles developed show high entrapment efficiency for both cytostatics and eugenol (EG) > 60% and release the drug in a prolonged manner for 40 h in a weakly acidic medium corresponding to the microenvironment of tumors. In a slightly alkaline environment, the drug circulates longer (more than 60 h). The thermal sensitivity of micelles is realized due to an increase in the molecular mobility of chitosan, which undergoes a phase transition at 32–37 °C. The effect of the cytostatic drug doxorubicin (Dox) on cancerous A549 cells and model healthy cells of human embryonic renal epithelium (HEK293T) was studied by FTIR spectroscopy and fluorescence microscopy. Micellar Dox penetrates into cancer cells 2–3 times more efficiently when using EG adjuvant, which inhibits efflux, as demonstrated by a significant increase in the ratio of intra- and extracellular concentrations of the cytostatic. However, here it is worth remembering about healthy cells that they should not be damaged: according to changes in the FTIR and fluorescence spectra, the penetration of Dox into HEK293T when using micelles in combination with EG is reduced by 20–30% compared to a simple cytostatic. Thus, experimental developments of combined micellar cytostatic drugs have been proposed to increase the effectiveness of cancer treatment and overcome multiple drug resistance.

Combretastatin derivatives is a promising class of antitumor agents, tubulin assembly inhibitors. However, due to poor solubility and insufficient selectivity to tumor cells, we believe, their therapeutic potential has not been fully realized yet. This paper describes polymeric micelles based on chitosan (a polycation that causes pH and thermosensitivity of micelles) and fatty acids (stearic, lipoic, oleic and mercaptoundecanoic), which were used as a carrier for a range of combretastatin derivatives and reference organic compounds, demonstrating otherwise impossible delivery to tumor cells, at the same time substantially reduced penetration into normal cells. Polymers containing sulfur atoms in hydrophobic tails form micelles with a zeta potential of about 30 mV, which increases to 40–45 mV when cytostatics are loaded. Polymers with tails of oleic and stearic acids form poorly charged micelles. The use of polymeric 400 nm micelles provides the dissolution of hydrophobic potential drug molecules. Micelles could significantly increase the selectivity of cytostatics against tumors, which has been shown using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, Fourier transform infrared (FTIR) spectroscopy, flow cytometry and fluorescence microscopy. Atomic force microscopy presented the difference between the unloaded micelles and those loaded with the drug: the size of the former was 30 nm on average, while the latter had a “disc-like” shape and a size of about 450 nm. The loading of drugs into the core of micelles was confirmed by UV and fluorescence spectroscopy methods; shifts of absorption and emission maxima into the long-wavelength region by tens of nm was observed. With FTIR spectroscopy, a high interaction efficiency of micelles with the drug on cells was demonstrated, but at the same time, selective absorption was observed: micellar cytostatics penetrate into A549 cancer cells 1.5–2 times better than the simple form of the drugs. Moreover, in normal HEK293T, the penetration of the drug is reduced. The proposed mechanism for reducing the accumulation of drugs in normal cells is the adsorption of micelles on the cell surface and the preservation of cytostatics to penetrate inside the cells. At the same time, in cancer cells, due to the structural features of the micelles, they penetrate inside, merging with the membrane and releasing the drug by pH- and glutathione-sensitive mechanisms. From a methodological point of view, we have proposed a powerful approach to the observation of micelles using a flow cytometer, which, in addition, allows us to quantify the cells that have absorbed/adsorbed cytostatic fluorophore and distinguish between specific and non-specific binding. Thus, we present polymeric micelles as drug delivery systems in tumors using the example of combretastatin derivatives and model fluorophore-cytostatic rhodamine 6G.

A simple and frugal method for fabricating inverse micropatterned photonic crystal (PhC) films aimed at miniaturization and multiplexing of opaline PhCs is described. First, highly uniform micropatterned synthetic opal structures in the form of periodic stripes are formed via stick‐slip motion of the meniscus during SiO 2 colloid solution evaporation. The prepared opal structures are then used as templates to produce inverse stripe patterned films with highly uniform colors via photopolymerization of ethoxylate trimethylolpropane triacrylate (ETPTA) photocurable resin. Local reflectance spectra are recorded to prove the PhC properties of the inverse stripes, and peaks over 40% associated with the first photonic stop band are observed. The readily fabrication process suggested here is an important step toward the development of many applications that can pave the technical road map for the next wave of innovations and breakthrough in PhCs for sensing. In particular, the resulting structures can be used as PhC arrays containing a line of periodically repeating sensor strips capable to detect the content of alcohols in water.

Visualization of the interaction of drugs with biological cells creates new approaches to improving the bioavailability, selectivity, and effectiveness of drugs. The use of CLSM and FTIR spectroscopy to study the interactions of antibacterial drugs with latent bacterial cells localized in macrophages create prospects to solve the problems of multidrug resistance (MDR) and severe cases. Here, the mechanism of rifampicin penetration into E. coli bacterial cells was studied by tracking the changes in the characteristic peaks of cell wall components and intracellular proteins. However, the effectiveness of the drug is determined not only by penetration, but also by efflux of the drugs molecules from the bacterial cells. Here, the efflux effect was studied and visualized using FTIR spectroscopy, as well as CLSM imaging. We have shown that because of efflux inhibition, eugenol acting as an adjuvant for rifampicin showed a significant (more than three times) increase in the antibiotic penetration and the maintenance of its intracellular concentration in E. coli (up to 72 h in a concentration of more than 2 μg/mL). In addition, optical methods have been applied to study the systems containing bacteria localized inside of macrophages (model of the latent form), where the availability of bacteria for antibiotics is reduced. Polyethylenimine grafted with cyclodextrin carrying trimannoside vector molecules was developed as a drug delivery system for macrophages. Such ligands were absorbed by CD206+ macrophages by 60–70% versus 10–15% for ligands with a non-specific galactose label. Owing to presence of ligands with trimannoside vectors, the increase in antibiotic concentration inside macrophages, and thus, its accumulation into dormant bacteria, is observed. In the future, the developed FTIR+CLSM techniques would be applicable for the diagnosis of bacterial infections and the adjustment of therapy strategies.