Exploring the In Vivo Biocompatibility of Dextran-Based Hydrogels

Dextran-based hydrogels have garnered attention in biomedical research for their potential applications in drug delivery and tissue engineering. A recent study evaluated the in vivo biocompatibility of both non-degradable dextran methacrylate (dex-MA) and degradable dextran-lactateHEMA (dex-lactateHEMA) hydrogels by implanting them subcutaneously in rats and observing tissue reactions over six weeks.

The initial immune response to dex-MA hydrogels involved a typical foreign body reaction characterized by the infiltration of granulocytes and macrophages along with the formation of fibrin and new blood vessels. Remarkably, the severity of this reaction varied based on the hydrogel's water content and degree of substitution (DS), with a milder response observed in gels with higher water content. Notably, by day 21, all dex-MA hydrogels had developed a fibrous capsule and demonstrated no toxic effects on surrounding tissues.

Contrastingly, the tissue reaction to dex-lactateHEMA hydrogels was less severe. This type of hydrogel exhibited an interesting behavior, progressively increasing in size and eventually dissolving completely over time. The degradation process was primarily linked to the hydrolysis of ester and carbonate bonds within the hydrogel's crosslinks, rather than enzymatic activity. By the three-week mark, macrophages and giant cells were noted to accumulate, containing remnants of the hydrogel, indicating an active degradation process.

Both types of hydrogels demonstrated biocompatibility, suggesting their potential use in medical applications. The study highlights the ability to tailor the degradation time of the dextran-based hydrogel system, which can range from two days to three months. This flexibility is crucial for optimizing drug release profiles and therapeutic effectiveness.

In summary, dextran-based hydrogels present unique properties as biocompatible materials for various biomedical applications. Their ability to control drug release and degradation rates positions them as promising candidates in the field of drug delivery systems and regenerative medicine. Researchers continue to explore the potential of these hydrogels, supported by funding from organizations like the Dutch Technology Foundation.