CuS nanoparticles (CuSNP) are degradable, readily prepared, inexpensive to produce and efficiently cleared from the body. In this work, we explored the feasibility of CuSNP to function as degradable near infrared (NIR) nanotransducers within fibrin-based cellular scaffolds. To prepare NIR-responsive CuSNP hydrogels, fibrinogen was dissolved in cell culture medium and supplemented with aqueous dispersions of CuSNP. Fibrinogen polymerization was catalyzed by the addition of thrombin. In some experiments, HUVEC, C3H/10T1/2 or C3H/10T1/2-fLuc cells, that harbor a heat-activated and rapamycin-dependent gene switch for regulating the expression of firefly luciferase transgene expression, were incorporated to the sol phase of the hydrogel. For in vivo experiments, hydrogels were injected subcutaneously in the back of adult C3H/HeN mice. Upon NIR irradiation, CuSNP hydrogels allowed heat-inducible and rapamycin-dependent transgene expression in cells contained therein, in vitro and in vivo. C3H/10T1/2 cells cultured in CuSNP hydrogels increased metabolic activity, survival rate and fibrinolytic activity, which correlated with changes at the transcriptome level. Media conditioned by CuSNP hydrogels increased viability of HUVEC which formed pseudocapillary structures and remodeled protein matrix when entrapped within these hydrogels. After long-term implantation, the skin patches that covered the CuSNP hydrogels showed increased capillary density which was not detected in mice implanted with matrices lacking CuSNP. In summary, NIR-responsive scaffolds harboring CuSNP offer compelling features in the tissue engineering field, as degradable implants with enhanced integration capacity in host tissues that can provide remote controlled deployment of therapeutic gene products.

Statement of significance

Hydrogels composed of fibrin embedding copper sulfide nanoparticles (CuSNP) efficiently convert incident near infrared (NIR) energy into heat and can function as cellular scaffolding. NIR laser irradiation of CuSNP hydrogels can be employed to remotely induce spatiotemporal patterns of transgene expression in genetically engineered multipotent stem cells. CuSNP incorporation in hydrogel architecture accelerates the cell-mediated degradation of the fibrin matrix and induces pro-angiogenic responses that may facilitation the integration of these NIR-responsive scaffolds in host tissues. CuSNP hydrogels that harbor cells capable of controlled expression of therapeutic gene products may be well suited for tissue engineering as they are biodegradable, enhance implant vascularization and an can be used to deploy growth factors in a desired spatiotemporal fashion.

中文翻译：

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促血管生成的近红外响应水凝胶，可实现有意的转基因表达

CuS纳米颗粒（CuSNP）可降解，易于制备，生产成本低廉并且可以从体内有效清除。在这项工作中，我们探索了CuSNP在基于纤维蛋白的细胞支架中作为可降解的近红外（NIR）纳米传感器的可行性。为了制备NIR反应性CuSNP水凝胶，将纤维蛋白原溶解在细胞培养基中，并补充CuSNP的水分散液。纤维蛋白原的聚合通过添加凝血酶来催化。在某些实验中，HUVEC，C3H / 10T1 / 2或C3H / 10T1 / 2-fLuc细胞具有热激活的雷帕霉素依赖性基因开关，用于调节萤火虫荧光素酶转基因表达的表达，并被整合到水凝胶。对于体内实验中，将水凝胶皮下注射到成年C3H / HeN小鼠的背部。经NIR照射后，CuSNP水凝胶可在体外和体内在其中包含的细胞中表达热诱导和雷帕霉素依赖性转基因。在CuSNP水凝胶中培养的C3H / 10T1 / 2细胞增加了代谢活性，存活率和纤溶活性，这与转录组水平的变化相关。以CuSNP水凝胶为条件的培养基增加了HUVEC的生存能力，当被困在这些水凝胶中时，HUVEC会形成假毛细血管结构和重塑的蛋白质基质。长期植入后，覆盖CuSNP水凝胶的皮肤斑块显示毛细血管密度增加，而在植入缺少CuSNP的基质的小鼠中未检测到毛细血管密度。总之，具有CuSNP的近红外响应支架在组织工程领域具有引人注目的功能，因为可降解植入物在宿主组织中具有增强的整合能力，可以提供治疗基因产物的远程控制部署。

重要声明

由纤维蛋白包埋的硫化铜纳米颗粒（CuSNP）组成的水凝胶可有效地将入射的近红外（NIR）能量转化为热量，并可以充当细胞支架。CuSNP水凝胶的NIR激光照射可用于远程诱导基因工程多能干细胞中转基因表达的时空模式。将CuSNP掺入水凝胶结构中可加速纤维蛋白基质的细胞介导降解，并诱导促血管生成反应，从而促进这些NIR响应支架在宿主组织中的整合。含有能够控制治疗性基因产物表达的细胞的CuSNP水凝胶非常适合组织工程，因为它们是可生物降解的，