Inflammation is tightly linked to tissue injury. In regenerative medicine, immune activation plays a key role in rejection of transplanted stem cells and reduces the efficacy of stem cell therapies. Next‐generation smart biomaterials are reported to possess multiple biologic properties for tissue repair. Here, the first use of 0D titanium carbide (Ti3C2) MXene quantum dots (MQDs) for immunomodulation is presented with the goal of enhancing material‐based tissue repair after injury. MQDs possess intrinsic immunomodulatory properties and selectively reduce activation of human CD4+IFN‐γ+ T‐lymphocytes (control 87.1 ± 2.0%, MQDs 68.3 ± 5.4%) while promoting expansion of immunosuppressive CD4+CD25+FoxP3+ regulatory T‐cells (control 5.5 ± 0.7%, MQDs 8.5 ± 0.8%) in a stimulated lymphocyte population. Furthermore, MQDs are biocompatible with bone marrow‐derived mesenchymal stem cells and induced pluripotent stem cell‐derived fibroblasts. Finally, Ti3C2 MQDs are incorporated into a chitosan‐based hydrogel to create a 3D platform with enhanced physicochemical properties for stem cell delivery and tissue repair. This composite hydrogel demonstrates increased conductivity while maintaining injectability and thermosensitivity. These findings suggest that this new class of biomaterials may help bridge the translational gap in material and stem cell‐based therapies for tissue repair and treatment of inflammatory and degenerative diseases.

Our in vitro study shows an alternative approach to rescue diseased LQTS2 phenotype via corrective re-trafficking therapy using a small chemical molecule, such as ALLN. This potentially novel approach may have ramifications in other clinically relevant trafficking disorders.

IntroductionDoxorubicin (DOX) is a well-known anticancer drug. However its clinical use has been limited due to cardiotoxic effects. One of the major concerns with DOX therapy is its toxicity in patients who are frail, particularly diabetics. Several studies suggest that mesenchymal stem cells (MSCs) have the potential to restore cardiac function after DOX-induced injury. However, limited data are available on the effects of MSC therapy on DOX-induced cardiac dysfunction in diabetics. Our objective was to test the efficacy of bone marrow-derived (BM-MSCs) and adipose-derived MSCs (AT-MSCs) from age-matched humans in a non-immune compromised rat model.MethodsDiabetes mellitus was induced in rats by streptozotocin injection (STZ, 65 mg/kg b.w, i.p.). Diabetic rats were treated with DOX (doxorubicin hydrochloride, 2.5 mg/kg b.w, i.p) 3 times/wk for 2 weeks (DOX group); or with DOX+ GFP labelled BM-MSCs (2x106cells, i.v.) or with DOX + GFP labelled AT-MSCs (2x106cells, i.v.). Echocardiography and Langendorff perfusion analyses were carried out to determine the heart function. Immunostaining and western blot analysis of the heart tissue was carried out for CD31 and to assess inflammation and fibrosis. Statistical analysis was carried out using SPSS and data are expressed as mean ± SD.ResultsGlucose levels in the STZ treated groups were significantly greater than control group. After 4 weeks of intravenous injection, the presence of injected MSCs in the heart was confirmed through fluorescent microscopy and real time PCR for ALU transcripts. Both BM-MSCs and AT-MSCs injection prevented DOX-induced deterioration of %FS, LVDP, dp/dt max and rate pressure product. Staining for CD31 showed a significant increase in the number of capillaries in BM-MSCs and AT-MSCs treated animals in comparison to DOX treated group. Assessment of the inflammation and fibrosis revealed a marked reduction in the DOX-induced increase in immune cell infiltration, collagen deposition and αSMA in the BM-MSCs and AT-MSCs groups.ConclusionsIn conclusion BM-MSCs and AT-MSCs were equally effective in mitigating DOX-induced cardiac damage by promoting angiogenesis, decreasing the infiltration of immune cells and collagen deposition.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-015-0142-x) contains supplementary material, which is available to authorized users.