Lee Wendy W Y, McCoy Colin P, Donnelly Ryan F, Bell Steven E J
School of Chemistry and Chemical Engineering, David Keir Building, Queen's University Belfast, Belfast, Northern Ireland, BT9 5AG, UK.
School of Pharmacy, Medical Biology Centre, BT9 7BL, UK.
Anal Chim Acta. 2016 Mar 17;912:111-6. doi: 10.1016/j.aca.2016.01.023. Epub 2016 Jan 27.
Large (10 × 10 cm) sheets of surface-enhanced Raman spectroscopy (SERS) active polymer have been prepared by stabilising metal nanoparticle aggregates within dry hydroxyethylcellulose (HEC) films. In these films the aggregates are protected by the polymer matrix during storage but in use they are released when aqueous analyte droplets cause the films to swell to their gel form. The fact that these "Poly-SERS" films can be prepared in bulk but then cut to size and stored in air before use means that they provide a cost effective and convenient method for routine SERS analysis. Here we have tested both Ag and Au Poly-SERS films for use in point-of-care monitoring of therapeutic drugs, using phenytoin as the test compound. Phenytoin in water could readily be detected using Ag Poly-SERS films but dissolving the compound in phosphate buffered saline (PBS) to mimic body fluid samples caused loss of the drug signal due to competition for metal surface sites from Cl(-) ions in the buffer solution. However, with Au Poly-SERS films there was no detectable interference from Cl(-) and these materials allowed phenytoin to be detected at 1.8 mg L(-1), even in PBS. The target range of detection of phenytoin in therapeutic drug monitoring is 10-20 mg L(-1). With the Au Poly-SERS films, the absolute signal generated by a given concentration of phenytoin was lower for the films than for the parent colloid but the SERS signals were still high enough to be used for therapeutic monitoring, so the cost in sensitivity for moving from simple aqueous colloids to films is not so large that it outweighs the advantages which the films bring for practical applications, in particular their ease of use and long shelf life.
通过在干燥的羟乙基纤维素（HEC）薄膜中稳定金属纳米颗粒聚集体，制备出了大面积（10×10厘米）的表面增强拉曼光谱（SERS）活性聚合物薄片。在这些薄膜中，聚集体在储存过程中受到聚合物基质的保护，但在使用时，当水性分析物液滴使薄膜膨胀成凝胶形式时，它们就会被释放出来。这些“聚SERS”薄膜可以大量制备，然后切割成所需尺寸并在空气中储存，直至使用，这意味着它们为常规SERS分析提供了一种经济高效且便捷的方法。在此，我们测试了银和金聚SERS薄膜用于治疗药物的即时检测，以苯妥英作为测试化合物。使用银聚SERS薄膜能够轻松检测水中的苯妥英，但将该化合物溶解在磷酸盐缓冲盐水（PBS）中以模拟体液样本时，由于缓冲溶液中的Cl⁻离子与金属表面位点竞争，导致药物信号丢失。然而，对于金聚SERS薄膜，未检测到Cl⁻的干扰，即使在PBS中，这些材料也能检测到浓度为1.8毫克/升的苯妥英。治疗药物监测中苯妥英的目标检测范围是10 - 20毫克/升。对于金聚SERS薄膜，给定浓度的苯妥英产生的绝对信号比母体胶体产生的信号低，但SERS信号仍然足够高，可用于治疗监测，因此从简单的水性胶体转变为薄膜所带来的灵敏度损失，并不足以抵消薄膜在实际应用中所带来的优势，特别是其易用性和长保质期。
