Furno Franck, Morley Kelly S, Wong Ben, Sharp Barry L, Arnold Polly L, Howdle Steven M, Bayston Roger, Brown Paul D, Winship Peter D, Reid Helen J
Biomaterials-Related Infection Group, School of Medical and Surgical Sciences, University of Nottingham, Nottingham NG7 2UH, UK.
J Antimicrob Chemother. 2004 Dec;54(6):1019-24. doi: 10.1093/jac/dkh478. Epub 2004 Nov 10.
Implantable devices are major risk factors for hospital-acquired infection. Biomaterials coated with silver oxide or silver alloy have all been used in attempts to reduce infection, in most cases with controversial or disappointing clinical results. We have developed a completely new approach using supercritical carbon dioxide to impregnate silicone with nanoparticulate silver metal. This study aimed to evaluate the impregnated polymer for antimicrobial activity.
After impregnation the nature of the impregnation was determined by transmission electron microscopy. Two series of polymer discs were then tested, one washed in deionized water and the other unwashed. In each series, half of the discs were coated with a plasma protein conditioning film. The serial plate transfer test was used as a screen for persisting activity. Bacterial adherence to the polymers and the rate of kill, and effect on planktonic bacteria were measured by chemiluminescence and viable counts. Release rates of silver ions from the polymers in the presence and absence of plasma was measured using inductively coupled plasma mass spectrometry (ICP-MS).
Tests for antimicrobial activity under various conditions showed mixed results, explained by the modes and rates of release of silver ions. While washing removed much of the initial activity there was continued release of silver ions. Unexpectedly, this was not blocked by conditioning film.
The methodology allows for the first time silver impregnation (as opposed to coating) of medical polymers and promises to lead to an antimicrobial biomaterial whose activity is not restricted by increasing antibiotic resistance.
可植入设备是医院获得性感染的主要风险因素。涂有氧化银或银合金的生物材料都曾被用于尝试减少感染，在大多数情况下临床结果存在争议或令人失望。我们开发了一种全新的方法，使用超临界二氧化碳将纳米颗粒银金属浸渍到硅酮中。本研究旨在评估浸渍后的聚合物的抗菌活性。
浸渍后，通过透射电子显微镜确定浸渍的性质。然后测试了两组聚合物圆盘，一组用去离子水清洗，另一组未清洗。在每组中，一半的圆盘涂有血浆蛋白调理膜。连续平板转移试验用作持续活性的筛选。通过化学发光和活菌计数测量细菌对聚合物的粘附、杀灭率以及对浮游细菌的影响。使用电感耦合等离子体质谱法（ICP-MS）测量在有和没有血浆存在的情况下聚合物中银离子的释放率。
在各种条件下的抗菌活性测试结果不一，这可以通过银离子的释放方式和速率来解释。虽然清洗去除了大部分初始活性，但银离子仍在持续释放。出乎意料的是，这并未被调理膜阻断。
该方法首次实现了医用聚合物的银浸渍（而非涂层），有望产生一种抗菌生物材料，其活性不受抗生素耐药性增加的限制。
