Newly designed Tissue/cell storage bag for cryopreserved homograft by application of CO2 laser welding technique.

Cryopreserved heart valve allografts (homografts) are packed in heat-sealed fluorinated ethylene propylene (FEP) film bag and stored under vapor phase of liquid nitrogen. Supply of those specific storage bags are very limited, and obtained from limited industries. On the other hand, sealing technique by CO2 laser enables secure closure using its high temperature (over 500 °C) beam, gives flexibility in sealing line design (not only straight but also any kind of curve or circle), and wider source of product supply can be expected with reasonable cost. This study is to assess the quality of newly designed tissue / cell storage bag for cryopreservation as domestic products by CO2 laser welding method, which enables drawing any types of sealing line (straight, curve) under any ambient temperature. Using CO2 laser (Firestar V40, Synrad Co. Ltd, USA), we designed homograft storage bag with FEP films (0.1 mm thick) under several sealing conditions (sealing width, laser intensity), with fixed operating speed (5 mm·s-1). We assessed the quality of welding line, and changes in neighboring film condition. Stability of welding was best achieved by laser intensity at 10.5 Watt (W), and acceptable at 13.5 W. Tensile test revealed that the line was stable against 20 Newton when sealing was done with laser intensity more than 10.5 W. We have also assessed structural changes of the sealing line and the neighboring film by polarizing microscope, which revealed fine foam formation at sealing line when laser intensity was high. CO2 laser sealing method is feasible in its stability and strength, and quality of the line was achieved when performed by appropriate laser intensity.

冷冻保存心脏瓣膜同种异体移植物（homografts，同种移植物）封装于热封型氟化乙烯丙烯（fluorinated ethylene propylene，FEP）薄膜袋中，储存于液氮气相环境内。这类专用储存袋的供应来源极为有限，仅能从少数厂商获取。相较之下，二氧化碳（CO₂）激光密封技术凭借其超过500℃的高温光束可实现可靠封口，且密封纹路设计灵活性更强——不仅可采用直线路径，亦支持任意曲线或圆形纹路，同时有望以合理成本获得更广泛的产品供应来源。本研究旨在评估采用CO₂激光焊接法制备的国产冷冻保存用组织/细胞储存袋的性能，该焊接法可在任意环境温度下加工出任意样式的密封纹路（直纹、曲线纹均可）。本研究使用美国Synrad有限公司生产的Firestar V40型CO₂激光器，以0.1mm厚的FEP薄膜制备同种移植物储存袋，在固定运行速度（5mm·s⁻¹）的前提下，调整多项密封参数（密封宽度、激光功率）开展实验。研究人员对焊接纹路的质量及相邻薄膜的状态变化进行了评估：当激光功率为10.5W时，焊接稳定性最佳；13.5W时亦可达到合格标准。拉伸试验结果显示，当激光功率高于10.5W时，密封纹路可承受20牛顿的拉力而保持稳定。研究团队还通过偏光显微镜对密封纹路及相邻薄膜的微观结构变化进行了评估，结果发现当激光功率过高时，密封纹路处会出现细微的气泡状孔隙。综上，CO₂激光密封技术在稳定性与强度层面均具备应用可行性，只要选用合适的激光功率，即可获得合格的密封纹路质量。