Preparation and characterization of hybrid hydrogels composed of physically cross-linked gelatin and liquid-crystalline filamentous viruses

Filamentous M13 phages act as components of materials toward various applications such as electronics, sensors, and biomedicine. To widen applicabilities of the phages, further development of methods for their utilization is required. Here, hybrid hydrogels composed of physically cross-linked gelatin and liquid-crystalline M13 phages are described. Mixing of the phages into gelatin hydrogels promoted the hydrogelation, and strengthened the mechanical strength. Liquid crystal formation of the phages in the hydrogels was evidenced by polarized optical microscopy observation. Degradation of the hydrogels by collagenase, which hydrolyzes gelatin, was suppressed by mixing the phages. These observations showed that the gelatin molecules were segregated into the spaces between phage lamellar structures. Our results will open attractive opportunities for simple construction of virus-based hybrid soft materials.