A nanostructured Cu(II) coordination polymer based on alanine as a tri-functional mimic enzyme and efficient composite in the detection of Sphingobacteria

This research raises the potential use of coordination polymers as new useful materials in two essential research fields, allowing the obtaining of a new multi artificial enzyme with the capacity to inhibit the growth of bacteria resistance. The fine selection of the ligands allows the designs of a new 2D Coordination Polymer (CP), with the formula [Cu2(IBA)2(OH2)4]n·6nH2O, by the combination of Cu(II) as the metal center with a pseudo amino acid (H2IBA =Isophthaloyl bis β-alanine). Quantitative total X-Ray Fluorescence (TXRF) analyses show that the obtained CP can gradually release Cu(II) ions. Additionally, this CP can be nano-processed and transformed into the metal-organic gel (MOG) by using different Cu(II) salts concentrations and the application of ultrasounds. Considering its nanometric dimensions, the slow Cu(II) release and its simple processability, its performance as an artificial enzyme, and its antibacterial ability were explored. The results obtained show the first nano-coordination polymer acting as an artificial multienzyme (peroxidase, catalase, and superoxodismutase) exhibiting antibacterial activity in the presence of hydrogen peroxide, with selective behavior for three bacterium strains (S. spiritovirum, A. faecales, and B. cereus). Indeed, this CP shows a more robust inhibition capacity for Sphingobacterium. Going beyond that, as there are no comfortable and practically clinical tests capable of detecting the presence of Sphingobacteria, the compound can be easily embedded to form moldable gelatin that will facilitate the handling and low-cost commercial kits

本研究探索了配位聚合物（Coordination Polymers）在两大核心研究领域作为新型功能材料的应用潜力，成功制备出一种可抑制耐药细菌生长的新型多人工酶。通过精准筛选配体，本研究以Cu(II)作为金属中心，结合伪氨基酸（H₂IBA=间苯二甲酰双β-丙氨酸），设计合成了化学式为[Cu₂(IBA)₂(OH₂)₄]ₙ·6nH₂O的新型二维配位聚合物（2D Coordination Polymer，CP）。全反射X射线荧光（Total X-Ray Fluorescence，TXRF）定量分析结果表明，所制备的CP可缓慢释放Cu(II)离子。此外，通过调控不同浓度的Cu(II)盐溶液并辅以超声处理，该CP可经纳米加工转化为金属有机凝胶（Metal-Organic Gel，MOG）。鉴于其纳米级尺寸、缓慢的Cu(II)释放特性与简便的加工性能，本研究进一步考察了该材料作为人工酶的性能与抗菌能力。研究结果显示，这是首例可作为人工多酶（过氧化物酶、过氧化氢酶与超氧化物歧化酶）的纳米配位聚合物，在过氧化氢存在条件下可展现抗菌活性，且对三种细菌菌株（S. spiritovirum、A. faecales与B. cereus）具有选择性抑制效果。该CP对鞘氨醇杆菌属（Sphingobacterium）的抑制能力尤为突出。此外，鉴于目前尚无便捷实用的临床检测方法可用于检测鞘氨醇杆菌的存在，该化合物可被便捷地嵌入可塑形明胶中，从而便于后续操作与低成本商用检测试剂盒的制备。