In Situ Fabrication of Double-Layered Hydrogels via Spray Processes to Prevent Postoperative Peritoneal Adhesion.

Postoperative peritoneal adhesions could cause pelvic pain, infertility, and bowel obstruction. In addition, adhesiolysis makes second surgery difficult. For the first time, we fabricated double-layered hydrogels in situ on the trauma surface via sequential double spray processes to prevent peritoneal adhesions. The spray conditions were optimized for spray distance and gas flow rate to create homogeneous and seamless double-layered hydrogels. The top layer was composed of alginate (Alg)-carboxymethyl cellulose (CMC) and serves as the barrier between the wounded tissue and surrounding tissues. The bottom layer was composed of Alg-gelatin (Gela) and comes in direct contact with the wounded tissue to promote wound healing. In vitro experiments showed that the Alg-Gela hydrogel layer promoted wound healing by accelerating horizontal cell migration. In addition, the Alg-CMC layer prevented the vertical penetration of fibroblast cells. The prevention efficacy of the sprayable double-layered hydrogels was evaluated using a partial hepatectomy-induced adhesion model in rats. The double-layered hydrogels decreased the adhesion grade and extent of liver cut surface, whereas the two single-layered hydrogels, Alg-CMC and Alg-Gela, did not show any adhesion prevention efficacy.

In actio optophysiological analyses reveal functional diversification of dopaminergic neurons in the nematode C. elegans.

Many neuronal groups such as dopamine-releasing (dopaminergic) neurons are functionally divergent, although the details of such divergence are not well understood. Dopamine in the nematode Caenorhabditis elegans modulates various neural functions and is released from four left-right pairs of neurons. The terminal identities of these dopaminergic neurons are regulated by the same genetic program, and previous studies have suggested that they are functionally redundant. In this study, however, we show functional divergence within the dopaminergic neurons of C. elegans. Because dopaminergic neurons of the animals were supposedly activated by mechanical stimulus upon entry into a lawn of their food bacteria, we developed a novel integrated microscope system that can auto-track a freely-moving (in actio) C. elegans to individually monitor and stimulate the neuronal activities of multiple neurons. We found that only head-dorsal pair of dopaminergic neurons (CEPD), but not head-ventral or posterior pairs, were preferentially activated upon food entry. In addition, the optogenetic activation of CEPD neurons alone exhibited effects similar to those observed upon food entry. Thus, our results demonstrated functional divergence in the genetically similar dopaminergic neurons, which may provide a new entry point toward understanding functional diversity of neurons beyond genetic terminal identification.