Progress in macrophage research is crucial for numerous applications in medicine, including cancer and infectious diseases. However, the existing methods to manipulate living macrophages are labor intense and inconvenient. Here we show that macrophage membranes can be reconstituted after storage for months at 4C, with their CD206 receptor selectivity and specificity being similar to that in the living cells. Then, we have developed a mannose ligand, specific to CD206, linked with PEG as IR spectroscopy marker to detect binding with the macrophage receptor. PEG was selected due to its unique adsorption band of C-O-C group at IR spectra, which does not overlap with other biomolecule’s spectroscopic feature. Next, competitive binding assay versus the PEG-bound ligand, has enabled selection of other higher-affinity ligands specific to CD206. Further, those higher-affinity ligands were used to differentiate activated macrophages in patient’s bronchoalveolar (BAL) or nasopharyngeal (NPL) lavage. CD206- control cells (HEK293T) showed only non-specific binding. Therefore, biochips based on reconstituted macrophage membranes as well as PEG-trimannoside as an IR spectroscopic marker, can be used to develop new methods facilitating macrophage research and macrophage-focused drug discovery.

The concept of targeted drug delivery can be described in terms of the drug’s ability to mimic the other biological objects’ property to localize to target cells or tissues. For example, drug delivery systems based on red blood cells or mimicking some of their useful features, such as long circulation in stealth mode, have been known for decades. On the contrary, therapeutic strategies based on macrophages have gained very limited attention until recently. Here we review two biomimetic strategies associated with macrophages, that can be used to develop new therapeutic modalities: First, the mimicry of certain types of macrophages (i.e., the use of macrophages, including tumor-associated, or macrophage-like particles as a carrier for targeted delivery of therapeutic agents); and Second, the mimicry of ligands, naturally absorbed by macrophages (i.e., the use of therapeutic agents specifically targeted at macrophages). We discuss potential applications of biomimetic systems involving macrophages for the new advancements in treatment of infections, inflammatory diseases, and cancer.

Chitosan and its derivatives as a biocompatible, biodegradable polymer that has been well-established in biotechnology and medicine as the nanogels and nanofilms forming material, has a number of practical applications in the field of the supply of medicines, food colloids, agrotechnology, as well. In this paper, the focus of attention is directed to the study of the physico-chemical principles of the formation of gels and nano-particles using fluorescence spectroscopy methods. We have obtained chitosan (Chit5) and pegylated chitosan (Chit5-PEG) particles with an average size of 170 or 400 nm, respectively by counterflow extrusion method. The paper presents three based fluorescent probes sensitive to the formation of chitosan particles: congo red, malachite green as well as covalently attached pyrene-label. Dyes fluoresce about an order of magnitude brighter in the composition of chitosan nanogel particles or in mscrogels. With these fluorescence probes, the pH- and temperature-dependent behavior of polymers was studied, and the influence of the genipin -based crosslinking agent on the gel formation parameters, such as kinetics and concentration dependence of the nanoparticles formation accompanied by sharply increases in the fluorescence intensity of dyes was evaluated. A sensitive approach for tracking gelation and including of small drug molecules and protein by FRET using a pyrene-tryptophan donor-acceptor pair is proposed using tryptophan or ovalbumin as fluorophores-donors. Upon nanogel formation FRET effect is observed manifested in sharp increase if the fluorescence intensity of the pyrene (acceptor). Thus, the application of the fluorescent probes with FRET function for monitoring the gelation and nanoparticles formation as well as drug encapsulation in chitosan-based parts, which have broad prospects in biomedical practice and food industry.

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.

Allylbenzenes (apiol, dillapiol, myristicin and allyltetramethoxybenzene) are individual components of plant essential oils that demonstrate antitumor activity, as well as enhancing effect on cytotoxic drugs such as paclitaxel, doxorubicin, cisplatin, etc. Triphenylphosphine (PPh3) derivatives of allylbenzenes are 2-3 orders of magnitude more potent than allylbenzenes in terms of IC50. Inhibition of efflux pumps has been reported for allylbenzenes, and PPh3 moiety is deemed to be responsible for preferential mitochondrial accumulation and depolarization of mitochondrial membranes. However, due to poor solubility the practical use of these substances has never been an option. Cyclodextrin-based (CD) molecular containers suggested here provided solubilization of allylbenzenes and its PPh3-derivatives. So, in this study we have observed an increase antitumor activity of paclitaxel in the presence of PPh3-derivatives adjuvants by an order of magnitude (in terms of IC50) against adenocarcinomic human alveolar basal epithelial cells A549. At the same time, they are quite powerful cytostatics themselves against A549 cells. On the other hand, the cytotoxic formulations developed show pronounced selectivity of the antiproliferation activity: high against tumor cells line (A549) and low toxicity of these composition was demonstrated on normal cells HEK293T, red blood cells, and sea urchin embryos (a model close to the human genome). On non-cancer HEK293T cells, it was shown that PPh3-derivatives of allylbenzenes at a concentration of 100 µM cause the death of about 20% of cells, while on A549 cancer cells, 85% of cells die. PPh3 derivatives of allylbenzenes, when solubilized in CD molecular containers, show remarkable potential as adjuvants to some of the widely used cytotoxic drugs.

Potentially, such an approach would significantly increase the effectiveness of therapy for a number of infectious and other diseases, reduce the dosage of antibiotics, shorten the duration of treatment, and reduce the risk of developing resistance. Moreover, the use of a polymer carrier with covalently bound organic molecules of different structures avoids problems with different (suboptimal) solubility and bio-distribution, which would be almost inevitable when using the same compounds separately. It would be very difficult to find antibiotic/adjuvant pairs that simultaneously achieve optimal concentrations in the same target cells. In our case, terpenoids and alkylbenzenes used as adjuvants are practically insoluble as individual compounds and their unacceptable pharmacological properties would not allow them to be used as efflux pump inhibitors.