Tissue engineering is a promising and revolutionary strategy to treat patients who suffer the loss or failure of an organ or tissue, with the aim to restore the dysfunctional tissues and enhance life expectancy. Supramolecular adhesive hydrogels are emerging as appealing materials for tissue engineering applications owing to their favorable attributes such as tailorable structure, inherent flexibility, excellent biocompatibility, near-physiological environment, dynamic mechanical strength, and particularly attractive self-adhesiveness. In this review, the key design principles and various supramolecular strategies to construct adhesive hydrogels are comprehensively summarized. Thereafter, the recent research progress regarding their tissue engineering applications, including primarily dermal tissue repair, muscle tissue repair, bone tissue repair, neural tissue repair, vascular tissue repair, oral tissue repair, corneal tissue repair, cardiac tissue repair, fetal membrane repair, hepatic tissue repair, and gastric tissue repair, is systematically highlighted. Finally, the scientific challenges and the remaining opportunities are underlined to show a full picture of the supramolecular adhesive hydrogels. This review is expected to offer comparative views and critical insights to inspire more advanced studies on supramolecular adhesive hydrogels and pave the way for different fields even beyond tissue engineering applications.

Supramolecular Adhesive Hydrogels for Tissue Engineering Applications.

https://doi.org/10.1016/j.ajps.2022.01.001

Antibacterial biomaterials for skin wound dressing

Wound dressings based on nanomaterials play a crucial role in wound treatment and are widely used in a whole range of medical settings, from minor to life-threatening tissue injuries. This article presents an educational review on the accumulating knowledge in this multidisciplinary area to lay out the challenges and opportunities that lie ahead and ignite the further and faster development of clinically valuable technologies. The review analyzes the functional advantages of nanomaterial-based gauzes and hydrogels as well as hybrid structures thereof. On this basis, the review presents state-of-the-art advances to transfer the (semi)blind approaches to the evaluation of a wound state to smart wound dressings that enable real-time monitoring and diagnostic functions that could help in wound evaluation during healing. This review explores the translation of nanomaterial-based wound dressings and related medical aspects into real-world use. The ongoing challenges and future opportunities associated with nanomaterial-based wound dressings and related clinical decisions are presented and reviewed.

Wound Dressing: From Nanomaterials to Diagnostic Dressings and Healing Evaluations.

Conductive hydrogels can be prepared by incorporating various conductive materials into polymeric network hydrogels. In recent years, conductive hydrogels have been developed and applied in the field of strain sensors owing to their unique properties, such as electrical conductivity, mechanical properties, self-healing, and anti-freezing properties. These remarkable properties allow conductive hydrogel-based strain sensors to show excellent performance for identifying external stimuli and detecting human body movement, even at subzero temperatures. This review summarizes the properties of conductive hydrogels and their application in the fabrication of strain sensors working in different modes. Finally, a brief prospectus for the development of conductive hydrogels in the future is provided.

Development of Conductive Hydrogels for Fabricating Flexible Strain Sensors.

Flexible Polydopamine Bioelectronics

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.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/advs.202003627

Highly Stretchable, Adhesive, Biocompatible, and Antibacterial Hydrogel Dressings for Wound Healing

Colorectal cancer (CRC) is often diagnosed at later stages after it has metastasized to other organs. The development of chemoresistance also contributes to a poor prognosis. Therefore, an increased understanding of the metastatic properties of CRC and chemoresistance could improve patient survival. CUGBP elav-like family member 1 (CELF1) is an RNA-binding protein, which is overexpressed in many human malignant tumors. However, the influence of CELF1 in CRC is unclear. V-ets erythroblastosis virus E26 oncogene homologue 2 (ETS2) is an evolutionarily conserved proto-oncogene known to be overexpressed in a variety of human cancers including CRC. In thespresent tudy, we investigated the association between CELF1 and ETS2 in CRC tumorigenesis and oxaliplatin (L-OHP) resistance. We found a positive correlation between the elevated expression of CELF1 and ETS2 in human CRC tissues. Overexpression of CELF1 increased CRC cell proliferation, migration, and invasion in vitro and in a xenograft tumor growth model in vivo, and induced resistance to L-OHP. In contrast, CELF1 knockdown improved the response of CRC cells to L-OHP. Overexpression of ETS2 increased the malignant behavior of CRC cells (growth, migration, and invasion) and L-OHP resistance in vitro. Moreover, L-OHP resistance induced by CELF1 overexpression was reversed by ETS2 knockdown. The results of luciferase reporter and ribonucleoprotein immunoprecipitation assays indicated that CELF1 up-regulates ETS2 by binding to its 3'-UTR. Taken together, our findings have identified that CELF1 regulates ETS2 in a mechanism that results in CRC tumorigenesis and L-OHP resistance, and CELF1 may be a promising target for overcoming chemoresistance in CRC.

RNA-binding protein CELF1 enhances cell migration, invasion, and chemoresistance by targeting ETS2 in colorectal cancer.

Radical excision versus local resection for primary rectal gastrointestinal stromal tumors. Cohort Study

Background Rectal gastrointestinal stromal tumor (GIST) is a rare digestive disease that has a distinct malignant tendency compared to that of gastric-derived GIST. At present, there is still no standard, and the surgical approach to rectal GIST is controversial. Methods The clinicopathological data and prognosis of rectal GIST patients admitted to the Sixth Affiliated Hospital of Sun Yat-sen University from 1998.01.01 to 2018.12.31 were collected retrospectively. All cases were divided into either the transanal (TA) group or the nontransanal (NTA) group. Results A total of 537 GIST cases were treated in 10 years, including 82 rectal GIST cases (64 cases underwent surgical resection, including 29 cases in the TA group and 35 cases in the NTA group). Preoperative neoadjuvant therapy (P=0.003), postoperative adjuvant therapy (P=0.017), operative time (P=0.013), blood loss (P=0.038), anus-preserver (P=0.048), 30-day complication rate (P=0.000), time to flatus (P=0.036), hospital stays (P=0.011), distance from the anus (P=0.047), tumor size (P=0.002), mitotic count (P=0.035) and National Institutes of Health (NIH) criteria (P=0.000) were significantly different between these two groups (all P<0.05). The median follow-up time was 41 (range, 1-122) months. Twelve patients had recurrence and metastasis, and 4 patients died. The 5-year disease-free survival (DFS) and overall survival (OS) were 74.4% and 91.2%, respectively, in the whole group. There were no statistically significant differences between the TA group and the NTA group at 5-year DFS (81.3% vs. 79.0%, P=0.243) and OS (88.7% vs. 93.3%, P=0.308). Conclusions In the treatment of rectal GIST, TA resection has a minimally invasive effect, less postoperative complications, high anal sphincter preservation rate, and R0 resection rate and a better prognosis. How to improve the proportion of neoadjuvant therapy and choose the appropriate cases for TA surgery is still a challenge.

https://atm.amegroups.com/article/download/35834/pdf

Transanal versus nontransanal surgery for the treatment of primary rectal gastrointestinal stromal tumors: a 10-year experience in a high-volume center.

Pelvic organ prolapse (POP) has become one of the most common serious diseases affecting parous women. Weakening of pelvic ligaments plays an essential role in the pathophysiology of POP. Currently, synthetic materials are widely applied for pelvic reconstructive surgery. However, synthetic nondegradable meshes for POP therapy cannot meet the clinical requirements due to its poor biocompatibility. Herein, we fabricated electrospun core-shell nanofibers of poly(l-lactic acid)-hyaluronic acid (PLLA/HA). After that, we combined them with mouse bone marrow-derived mesenchymal stem cells (mBMSCs) to assess the cellular response and pelvic ligament tissue engineering in vitro. The cellular responses on the composite nanofibers showed that the core-shell structure nanofibers displayed with excellent biocompatibility and enhanced cellular activity without cytotoxicity. Moreover, compared with PLLA nanofibers seeded with mBMSCs, PLLA/HA nanofibers exhibited more cellular function, as revealed by the quantitative real-time polymerase chain reaction (RT-qPCR) for pelvic ligament-related gene markers including Col1a1, Col1a3 and Tnc. These features suggested that this novel core-shell nanofiber is promising in stem cell-based tissue engineering for pelvic reconstruction.

Guo Wentai

Papers

Highly Stretchable, Adhesive, Biocompatible, and Antibacterial Hydrogel Dressings for Wound Healing

RNA-binding protein CELF1 enhances cell migration, invasion, and chemoresistance by targeting ETS2 in colorectal cancer.

Radical excision versus local resection for primary rectal gastrointestinal stromal tumors. Cohort Study

Transanal versus nontransanal surgery for the treatment of primary rectal gastrointestinal stromal tumors: a 10-year experience in a high-volume center.

Core-Shell Poly(l-lactic acid)-Hyaluronic Acid Nanofibers for Cell Culture and Pelvic Ligament Tissue Engineering.