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To coordinate the trade-off between the separation and permeation of the nanofiltration membrane for the separation of Mg2+/Li+, we regulated poly(ethyleneimine)/piperazine interface polymerization parameters to construct a positively/negatively charged ultrathin Janus nanofiltration membrane at a free aqueous–organic interface. At the optimized interfacial polymerization parameters, 0.03 wt % of piperazine reacted with trimethylbenzene chloride prior to poly(ethyleneimine), forming a primary polyamide layer with fewer defects or limiting large-scale defects of the polyamide layer. The controlled subsequent reaction of poly(ethyleneimine) and trimethylbenzene chloride results in a Janus nanofiltration membrane, with one side enriched with the carboxyl groups, the other side enriched with the amine groups, and a dense polyamide structure in the middle. Under the optimum conditions, the positive potential of the rear surface of the prepared membrane was 14.57 mV, and the water contact angle reached 71.31°, while the negative potential of the front surface was −25.48 mV, and the water contact angle was 12.93°, confirming a Janus membrane with opposite charges and large hydrophilicity differences in the front and rear surfaces. With a high cross-linking degree, a 40 nm thick polyamide layer is 29.09% more thinner than the traditional polyamide membrane. The ultrathin Janus nanofiltration membrane showed an excellent separation factor (SLi,Mgof 18.26), stability, and water permeability flux (10.6 L·m–2·h–1·bar–1). The rejections to MgCl2, CaCl2, MgSO4, and Na2SO4are measured above 90% at a nearly constant permeability of 10.6 L·m–2·h–1·bar–1, particularly stable rejections to MgCl2and Na2SO4.

Postoperative treatment of osteosarcoma is one of the major challenging clinical issues since both elimination of residual tumors and acceleration of bone regeneration should be considered. Photothermal therapy has been widely studied due to its advantages of small side-effect, low-toxicity, high local selectivity and noninversion, and bone tissue engineering is an inevitable trend in postoperative treatment of osteosarcoma. In this study, we combined the tissue engineering and photothermal therapy together, and developed a kind of multifunctional nanofibrous 3D matrixes for postoperative treatment of osteosarcoma. The flexible bioactive glass nanofibers (BGNFs) prepared by sol–gel electrospinning and calcination acted as the basic blocks, and the genipin-crosslinked gelatin (GNP-Gel) acted as the cement to bond the BGNFs forming a stable 3D structure. The stable porous 3D scaffolds were obtained through ice crystal templating method and freeze-drying technology. The obtained GNP-Gel/BGNF 3D matrixes showed a nanofibrous structure that highly biomimetics the extracellular matrix. The excellent compression recovery performance in water of these matrixes made them suitable for minimally invasive surgery. In addition, these 3D matrixes were not only biocompatible in vitro, but also benefit for the formation of mineralized bone in vivo. Furthermore, the dark blue GNP-Gel also acted as the photothermal agent, which endowed the GNP-Gel/BGNF 3D matrixes with efficient photothermal antitumor and photothermal antibacterial performance without addition of other toxic photothermal agents. Therefore, this study provides an ingenious avenue to prepare multifunctional nanofibrous 3D matrixes with photothermal therapy for postoperative treatment of osteosarcoma.