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Mechanical responsiveness is an important property of core–shell carriers. To realize the quantitative design of the mechanical responsiveness of the carrier, the design and preparation of core–shell particles were carried out by combining theory with experiments. The results shows that the inner radius, outer radius, and shell elastic modulus of the core–shell particles, as well as the elastic modulus of the matrix all affect the stress distribution in the carrier-matrix region. The elastic modulus of the shell is the main material parameter that determines the mechanical responsiveness. For a carrier of a specific size, the simultaneous cracking of the carrier and the substrate can be achieved by adjusting the elastic modulus of the shell, and the theoretical design calculations were established. The theoretical design method has been verified by numerical and experimental results.

The use of a controlled-release drug carrier is an innovative solution for the treatment of local infections, in particular in dentistry, skin diseases, and in open wounds. The biocompatibility, biodegradability, the possibility of a large amount of drug adsorbed (especially those with hydrophilic properties), and the ability to create structures of any shape and size are the reasons for hydrogels to be frequently studied. The main disadvantage of hydrogel carriers is the rapid rate of drug release; hence, in this study, an attempt was made to additionally chemically cross-link 1-ethyl-3-(3-dimethyl aminopropyl)-1-carbodiimide hydrochloride (EDC) with the hyaluronic acid–alginate (HA–SAL) structure. The answer to significantly reduce the mass flux typical for hydrogel structure was to surround it with a polymer layer using a dry cover. By coating the carriers with polylactide, the release time was increased by around forty times. As the carriers were designed to reduce local bacterial infections, among others in dentistry, the released antibiotics were amoxycillin, metronidazole, and doxycycline. [ABSTRACT FROM AUTHOR]

The use of a controlled-release drug carrier is an innovative solution for the treatment of local infections, in particular in dentistry, skin diseases, and in open wounds. The biocompatibility, biodegradability, the possibility of a large amount of drug adsorbed (especially those with hydrophilic properties), and the ability to create structures of any shape and size are the reasons for hydrogels to be frequently studied. The main disadvantage of hydrogel carriers is the rapid rate of drug release; hence, in this study, an attempt was made to additionally chemically cross-link 1-ethyl-3-(3-dimethyl aminopropyl)-1-carbodiimide hydrochloride (EDC) with the hyaluronic acid–alginate (HA–SAL) structure. The answer to significantly reduce the mass flux typical for hydrogel structure was to surround it with a polymer layer using a dry cover. By coating the carriers with polylactide, the release time was increased by around forty times. As the carriers were designed to reduce local bacterial infections, among others in dentistry, the released antibiotics were amoxycillin, metronidazole, and doxycycline.

Graphene oxide (GO), due to its properties, such as nanometric dimensions, large specific surface area, and biocompatibility, can be used as a carrier in controlled drug release systems. The method of its chemical activation before drug molecules binding was elaborated. Doxorubicin (DOX), an anticancer drug, was attached to the surface of GO via the Gly-Gly-Leu linker. Approximately 3.07 · 1020 molecules of the tripeptide were attached to 1 g of GO and subsequently almost the same number of DOX molecules. GO was suspended inside a sol surrounded by a thin porous membrane. The bound DOX was effectively released using thermolysin, an enzyme cleaving peptide bonds between Gly and Leu inside the linker structure. The membrane, as the shell was responsible for keeping enzyme molecules in their native form and GO flakes inside the carrier, simultaneously allowed the released drug molecules to diffuse outside. The rate of drug release was described as a function of the enzyme concentration and mass of DOX expressed on carrier volume; thus, the daily dose and length of the therapy can be controlled. Studies involving the cell line of mice fibrosarcoma WEHI 164 have shown that the prepared carrier itself is not toxic and only the introduction of DOX-releasing enzyme into it causes cell death. Unlabelled Image • The paper presents the innovative preparation of a core-shell drug carriers based on graphene oxide. • The chemically bounded doxorubicin is released by enzymatic reaction. • A native form of thermolysin is active and stable in sol surrounded by a thin polymeric layer. • Drug release controlled by an enzymatic hydrolysis can be applied in a long-term therapy. [ABSTRACT FROM AUTHOR]