**5. Tissue Engineering and Biomaterial**

GAGs are native components of the ECM that drive cell behavior and control the microenvironment surrounding cells, making them promising therapeutic targets for many diseases. Recent studies have shown that the recapitulation of cell interactions with ECM is critical in tissue engineering, which aims to mimic and regenerate endogenous tissues. Because of this, the incorporation of GAGs to drive stem cell fate and to promote cell proliferation in engineered tissues has gained increasing attention. This review article [16] summarizes the role of glycosaminoglycans in tissue engineering and their recent use in these constructs. In addition, the evaluation of the general research trends in this niche offers insight into future research directions in this field.

Hyaluronan displays such properties as biocompatibility, biodegradability, high viscoelasticity, and immunoneutrality, making it attractive for biomedical and pharmaceutical applications. Furthermore, from the standpoint of physical properties, the polyelectrolyte nature of negatively charged hyaluronan provides a way to create new high-performance complexes. One such complex occurs when hyaluronan self-assembles with a positively charged lactose-modified chitosan. The authors of this investigation [17] show that the complex that is formed has a monodisperse molecular weight distribution and a high viscosity and is susceptible to enzymic degradation by hyaluronidase and lysozyme. Due to the wide range of applications in biomedicine and biotechnology, the development of such polyelectrolyte complexes is of scientific and biotechnological interest.

The conjunction of the wide range of biological activities and unique physicochemical properties confer a distinctive place as an implantable biomaterial used in orthopedics and traumatology to hyaluronan. Infections related to implanted medical devices depend on the bacterial capability to establish highly structured multilayered biofilms on artificial surfaces. One way to prevent such peri-implant infection is to apply an implanted biomaterial, defensive antibacterial coating (DAC), which can act as a resorbable barrier that delivers local antibiofilm and antibacterial compounds. The copolymer of hyaluronic acid and poly-D, L-lactic acid produces a hydrogel that retains the hydrophobic character of the poly-D, L-lactide sidechains and the hydrophilic character of a hyaluronic acid backbone. The suitability of such a hydrogel depends on the stability and degradation of both the hyaluronan backbone and the polylactic chains over time and temperature. T. Guzzo and her collaborators [18] performed chromatographic analysis and explored the suitability of diffusion-ordered NMR spectroscopy to characterize the outcome of the biomaterial over time in physiological conditions.
