Extracellular vesicle-matrix interactions.

The extracellular matrix in microenvironments harbors a variety of signals to control cellular functions and the materiality of tissues. Most efforts to synthetically reconstitute the matrix by biomaterial design have focused on decoupling cell-secreted and polymer-based cues. Cells package molecules into nanoscale lipid membrane-bound extracellular vesicles and secrete them. Thus, extracellular vesicles inherently interact with the meshwork of the extracellular matrix. In this Review, we discuss various aspects of extracellular vesicle-matrix interactions. Cells receive feedback from the extracellular matrix and leverage intracellular processes to control the biogenesis of extracellular vesicles. Once secreted, various biomolecular and biophysical factors determine whether extracellular vesicles are locally incorporated into the matrix or transported out of the matrix to be taken up by other cells or deposited into tissues at a distal location. These insights can be utilized to develop engineered biomaterials where EV release and retention can be precisely controlled in host tissue to elicit various biological and therapeutic outcomes.

Cell-based dressings: A journey through chronic wound management.

The field of regenerative medicine has undergone a paradigm shift in recent decades thanks to the emergence of novel therapies based on the use of living organisms. The development of cell-based strategies has become a trend for the treatment of different conditions and pathologies. In this sense, the need for more adequate, biomimetic and well-planned treatments for chronic wounds has found different and innovative strategies, based on the combination of cells with dressings, which seek to revolutionize the wound healing management. Therefore, the objective of this review is to analyze the current state and the latest advances in the research of cell-based dressings for chronic wounds, ranging from traditional and "second generation" bioengineered living skin equivalents to mesenchymal stem cell dressings; the latter include biopolymeric porous scaffolds, electrospun nanofiber meshes, hydrogels and 3D printed bio-printed dressings. Finally, this review updates the completed and ongoing clinical trials in this field and encourages researchers to rethink these new approaches, manufacturing processes and mechanisms of action, as well as their administration strategies and timings.

Structure-properties relationship of chitosan/collagen films with potential for biomedical applications.

Chitosan/collagen films were developed and characterized in order to assess the suitability of these films for biomedical applications. Hence, physicochemical, thermal, barrier and mechanical properties were analyzed and related to the film structure, which showed the prevalence of the triple helix of native collagen after the addition of chitosan. Furthermore, collagen fiber diameter changed from 3.9 ±â€¯0.6 µm, for collagen films without chitosan, to 1.8 ±â€¯0.5 µm, for collagen films with low molecular weight chitosan. These results suggested interactions between collagen and chitosan molecules, as observed by Fourier transform infrared (FTIR) analysis. Regarding film barrier properties, chitosan/collagen films showed a water vapor transmission rate around 1174 g m-2 day-1, suitable for biomedical applications such as wound healing. Additionally, biological tests confirmed that the chitosan/collagen films developed are suitable for biomedical applications.