Treatment of wounds in special areas is challenging due to inevitable movements and difficult fixation. Common cotton gauze suffers from incomplete joint surface coverage, confinement of joint movement, lack of antibacterial function, and frequent replacements. Hydrogels have been considered as good candidates for wound dressing because of their good flexibility and biocompatibility. Nevertheless, the adhesive, mechanical, and antibacterial properties of conventional hydrogels are not satisfactory. Herein, cationic polyelectrolyte brushes grafted from bacterial cellulose (BC) nanofibers are introduced into polydopamine/polyacrylamide hydrogels. The 1D polymer brushes have rigid BC backbones to enhance mechanical property of hydrogels, realizing high tensile strength (21–51 kPa), large tensile strain (899–1047%), and ideal compressive property. Positively charged quaternary ammonium groups of tethered polymer brushes provide long‐lasting antibacterial property to hydrogels and promote crawling and proliferation of negatively charged epidermis cells. Moreover, the hydrogels are rich in catechol groups and capable of adhering to various surfaces, meeting adhesive demand of large movement for special areas. With the above merits, the hydrogels demonstrate less inflammatory response and faster healing speed for in vivo wound healing on rats. Therefore, the multifunctional hydrogels show stable covering, little displacement, long‐lasting antibacteria, and fast wound healing, demonstrating promise in wound dressing.

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Designing scaffolds with persistent elasticity and conductivity to mimic microenvironments becomes a feasible way to repair cardiac tissue. Injectable biomaterials for cardiac tissue engineering have demonstrated the ability to restore cardiac function by preventing ventricular dilation, enhancing angiogenesis, and improving conduction velocity. However, limitations are still among them, such as poor mechanical stability, low conductivity, and complicated procedure. Here, we developed thermal plastic poly­(glycolic acid) surgical suture and mussel-inspired conductive particle’s adhesion into a highly elastic, conductive spring-like coils. The polypyrrole (PPy)-coated biospring acted as an electrode and then was assembled into a solid-state supercapacitor. After being injected through a syringe needle (0.33 mm inner diameter), the tangled coils formed an elastically conductive three-dimensional (3-D) network to modulate cardiac function. We found that cardiomyocytes (CMs) grew along the spring coils’ track with elongated morphologies and formed highly oriented sarcomeres. The biospring enhanced the CMs’ maturation in synchronous contraction accompanied by high expressions of cardiac-specific proteins, α-actinin, and connexin 43 (cx43). After the elastic, conductive biosprings were injected into the myocardial infarction (MI) area, the left ventricular fractional shortening was improved by about 12.6% and the infarct size was decreased by about 34%. Interestingly, the spring can be utilized as a sensor to measure the CMs’ contractile force, which was 1.57 × 10–3 ± 0.26 × 10–3 mN (∼4.1 × 106 cells). Accordingly, this study highlights an injectable biospring to form a tangled conductive 3-D network in vivo for MI repair.

The controversy between polypyrrole's (Ppy) biocompatibility and its aggregation on nanofibers impedes application of conductive Ppy-incorporated nanofibers to create engineered cardiac microenvironments. The purpose of this study was to fabricate a functional scaffold for engineering cardiac patches (ECP) using a high concentration of methyl acrylic anhydride-gelatin (GelMA)-Ppy nanoparticles, mussel-inspired crosslinker, and electrospun (ES)-GelMA/polycaprolactone (PCL) nanofibrous membrane.Methods: First, spherical GelMA-Ppy nanoparticles were obtained when the methacrylate groups of GelMA formed a self-crosslinked network through oxidative polymerization of Ppy. Second, GelMA-Ppy nanoparticles were uniformly crosslinked on the ES-GelMA/PCL membrane through mussel-inspired dopamine-N'N'-methylene-bis-acrylamide (dopamine-MBA) crosslinker. Finally, the feasibility of the dopa-based conductive functional ECP scaffold was investigated in vitro and in vivo.Results: The GelMA-Ppy nanoparticles displayed excellent biocompatibility at a high concentration of 50 mg/mL. The massive GelMA-Ppy nanoparticles could be uniformly distributed on the ES nanofibers through dopamine-MBA crosslinker without obvious aggregation. The high concentration of GelMA-Ppy nanoparticles produced high conductivity of the dopamine-based (dopa-based) conductive membrane, which enhanced the function of cardiomyocytes (CMs) and yielded their synchronous contraction. GelMA-Ppy nanoparticles could also modify the topography of the pristine ES-GelMA/PCL membrane to promote vascularization in vitro. Following transplantation of the conductive membrane-derived ECP on the infarcted heart for 4 weeks, the infarct area was decreased by about 50%, the left ventricular shortening fraction percent (LVFS%) was increased by about 20%, and the neovascular density in the infarct area was significantly increased by about 9 times compared with that in the MI group.Conclusion: Our study reported a facile and effective approach to developing a functional ECP that was based on a mussel-inspired conductive nanofibrous membrane. This functional ECP could repair infarct myocardium through enhancing cardiac function and revascularization.

Background: Creation of a temporary diverting stoma during rectal cancer surgery is used widely to prevent undesirable outcomes related to anastomotic leakage (AL). The transition from temporary stoma (TS) to permanent stoma (PS) is a frequent outcome. Elderly patients may have a greater probability of PS. We aimed to identify risk factors of PS and developed a nomogram to predict the rate of PS for elderly patients.Methods: We enrolled elderly patients (≥70 years) who underwent rectal cancer surgery with a TS between January 2014 and December 2017 at our hospital. We divided patients into two groups: a TS group and a PS group. We then identified the risk factors for PS and developed a nomogram to predict the possibility of PS.Results: Of the 278 elderly patients who received a diverting stoma, 220 (79.14%) eventually underwent stoma reversal, and 58 (20.86%) had PS. The proportion of males in the PS group was significantly higher than that of the TS group (P=0.048). Univariate and multivariate analysis showed that American Society of Anesthesiologists (ASA) score (P<0.001), laparotomy (P=0.004), AL (P<0.001), and tumor recurrence (P<0.001) were significantly correlated with PS. These four factors were included to construct the nomogram. The consistency index of the nomogram was 0.833 and the model yielded an area under the curve of 0.833.Conclusions: ASA score (≥3), laparotomy, AL, and tumor recurrence were independent risk factors for PS in elderly patients. Our nomogram exhibited moderate predictive ability.