Exosomes are a subpopulation of extravascular vesicles with a diameter of 30–150 nm. They are cellular-communication mediators, often reaching very distant organism tissues. Information is transferred by exosomal cargo, composed of a wide variety of macromolecules such as nucleic acids, proteins, and lipids. Exosomes possess natural specific cell targeting properties that are desirable in designing targeted macromolecules (DNA and RNA) and drug delivery systems (doxorubicin, paclitaxel, and taxol). In this context, exosomes can be defined as bio-derived drug transporting and protecting devices for the treatment of bacterial (toxoplasmosis and salmonellosis), viral (AIDS and hepatitis B), and cancer (lung, pancreatic, colon, brain, and breast) diseases. Extensive research proves that exosomes’ natural cargo can double-act, both increasing and decreasing the disease severity. In this case, the exosomes need to be prepared, namely, their origin and their cargo need to be screened and known. Thus, appropriate methods for intact and price-effective exosome isolation are needed with further exosome properties description. Among many utilized isolation methods, the most common are ultracentrifugation, polymer-based precipitation, and affinity precipitation-isolation systems, but novel microfluidic methods compromising high efficacy and purity are being developed. In this review, we state the current knowledge and trends in exosome-based drug delivery systems.

Natural xanthones are a large group of compounds from which promising anticancer properties could be further developed by chemical modifications. This study aimed to investigate the influence of four novel xanthone derivatives based on a naturally occurring xanthone skeleton on the invasiveness of colon cancer cells in vitro. First, the concentrations required to inhibit growth of three colorectal cancer cell lines to 50% (GI₅₀) of all the studied compounds, as well as the natural xanthones used as a reference (gambogic acid and α-mangostin), have been established (MTS reduction test). Next, the assays determining several aspects of the GI₂₅ xanthones influence on colorectal cancer cells, including cytotoxicity, migration and invasion potential, interaction with extracellular matrix and endothelial cells, as well as expression of selected invasiveness related genes have been performed. Our results demonstrate that these novel xanthone derivatives impair colorectal cancer proliferation, motility, adhesion to extracellular matrix and to endothelial cells, and also induce apoptosis and cell death. Moreover, their activity is comparable to cisplatin and 5-fluorouracil, used as reference compounds. Conducted research indicates our compounds for further research and development as novel drugs in colorectal cancer treatment.

In this study, lithium borohydride (LiBH₄) reduction was used to modify the surface chemistry of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibers. Although the most common reaction employed in the surface treatment of polyester materials is hydrolysis, it is not suitable for fiber modification of bacterial polyesters, which are highly resistant to this type of reaction. The use of LiBH₄ allowed the formation of surface hydroxyl groups under very mild conditions, which was crucial for maintaining the fibers’ integrity. The presence of these groups resulted in a noticeable improvement in the surface hydrophilicity of PHBV, as revealed by contact angle measurements. After the treatment with a LiBH₄ solution, the electrospun PHBV fibrous mat had a significantly greater number of viable osteoblast-like cells (SaOS-2 cell line) than the untreated mat. Moreover, the results of the cell proliferation measurements correlated well with the observed cell morphology. The most flattened SaOS-2 cells were found on the surface that supported the best cell attachment. Most importantly, the results of our study indicated that the degree of surface modification could be controlled by changing the degradation time and concentration of the borohydride solution. This was of great importance since it allowed optimization of the surface properties to achieve the highest cell-proliferation capacity.

In order to improve naturally occurring xanthones’ anticancer properties, chemical synthesis is proposed. In this study, from eight novel xanthone derivatives coupled to morpholine or aminoalkyl morpholine, only the two most active ones were chosen. For additional enhancement of the anticancer activity of our tested compounds, we combined chemotherapy with hyperthermia in the range of 39–41 °C, from which the mild conditions of 39 °C were the most influencing. This approach had a profound impact on the anticancer properties of the tested compounds. TOV-21G and SC-OV-3 ovarian cell line motility and metastasis behavior were tested in native and hyperthermia conditions, indicating decreased wound healing properties and clonogenic activity. Similarly, the expression of genes involved in metastasis was hampered. The expression of heat shock proteins involved in cancer progression (Hsc70, HSP90A, and HSP90B) was significantly influenced by xanthone derivatives. Chemotherapy in mild hyperthermia conditions had also an impact on decreasing mitochondria potential, visualized with JC-1. Synthetic xanthone ring modifications may increase the anticancer activity of the obtained substances. Additional improvement of their activity can be achieved by applying mild hyperthermia conditions. Further development of a combined anticancer therapy approach may result in increasing currently known chemotherapeutics, resulting in a greater recovery rate and diminishment of the cytotoxicity of drugs.

Latanoprost (LTP) is a prostaglandin F_2α analog used to lower intraocular pressure in glaucoma treatment administered daily as eye drops. In this study, a universal model based on poly(l-lactide-co-glycolide-co-trimethylene carbonate) with shape memory was proposed for the development of a solid biodegradable formulation with prolonged release administered intraconjunctivally, intravitreally, subconjunctivally, and subcutaneously. Solution casting and electron beam (EB) irradiation were applied to the matrix formulation. The properties of the native matrix and matrices degraded in a PBS buffer (pH 7.4) were monitored by NMR, DSC, GPC, and SEM. Water uptake (WU) and weight loss (WL) were also analyzed. LTP was released over 113 days in a tri-phasic and sigmoidal pattern without a burst effect and with a relatively long second release phase, in which changes were observed in the glass transition temperature, molecular weight (M_n), WU, and WL. EB irradiation decreased the initial M_n, increased WU, and accelerated LTP release with a shortened lag phase. This provides the opportunity to partially eliminate the use of drops at the start of treatment. SEM observations indicated that surface erosion is the prevalent degradation mechanism. The proposed model is an interesting solution during a preliminary study to develop final medicinal products that provide high adherence.