結構類似物干擾對拓印光子晶體感測能力的影響

Abstract

本研究針對雙酚A (Bisphenol A, BPA)、 雙（2-羥基苯基）甲烷 (Bis(2-hydroxyphenyl)methane, 2HDPM)與苯酚 (phenol)製備高選擇性之拓印反蛋白石光子晶體感測器，並瞭解目標物與結構類似物之間的相互影響作用力對感測能力的影響。在感測能力試驗結果中，感測器對標的物皆具有高選擇性及廣泛的線性範圍(0.4~120 mg/L)，最低偵測極限可達0.4~0.5 mg/L，而在結構類似物干擾試驗中，結構類似物對目標物的吸引力(π-π作用力)若大於拓印孔洞與目標物間的鍵結引力，便會使目標物受到抑制干擾，抑制程度隨結構類似物的濃度增加而增加，此外，目標物的尺寸大小及立體結構亦會影響目標物進入拓印孔洞的難易度，BPA與2HDPM結構與大小相似，然而2HDPM的立體結構對稱，因此較容易進入拓印孔洞中，使phenol對其抑制影響較BPA輕微，另外，phenol由於分子小，較容易進入拓印孔洞，因此BPA與2HDPM對phenol感測的抑制程度較低。另外，在線性試驗中結構類似物的存在皆會抑制感測器的響應能力，使線性截距下降，對於大分子BPA與2HDPM拓印感測器而言，當標的物濃度高時，結構類似物對感測能力的干擾變得不明顯，而對於phenol拓印感測器而言，由於類似物間的親和力較弱，因此抑制影響便不隨類似物相對濃度增加而增加，以致線性斜率不變。整體結果顯示結構類似物對於感測能力的影響主要為抑制作用，且標的物與結構類似物間的π-π作用力為抑制標的物進入拓印孔洞的主要因素。

Three inverse opal photonic crystal sensors imprinted with Bisphenol A (BPA), Bis(2-hydroxyphenyl)methane (2HDPM), and phenol were prepared, and the influence of interactions between target analyte and structural analogues on their sensing performance were investigated. Results indicate that all these imprinted sensors exhibited high selectivity, a broad linear range (0.4~120 mg/L), and low detection limits (0.4~0.5 mg/L). The interference test showed that the response of the sensors was suppressed when the π-π interaction between the target and its structural analogues is stronger than the interaction between imprint cavities and the target. In addition, the inhibition increases with increasing concentrations of analogues. The molecular size and stereogeometry of analytes determine how easy the target can bind into the imprinted cavities. Although BPA and 2HDPM are similar in size and structure, the symmetrical stereo-structure of 2HDPM enables this compound easier to fit in the imprinted cavity, thereby the inhibition effect of phenol on 2HDPM sensing is slightly lower than that on BPA sensing. On the other hand, the sensing ability of the phenol-imprinted sensor was less interfered by 2HDPM and BPA because the smaller molecular size of phenol facilitates its binding into the cavities. The linear test revealed that the presence of analogues inhibited response and led to decrease of linear intercept. The interference became insignificant for the BPA- and 2HDPM-imprinted sensors when the target concentration was increased. Due to weak affinity of phenol toward analogues, the slope of the linearity of the phenol-imprinted sensor was insignificantly affect by the matrix except for slightly decrease in intercept. These results clearly demonstrated that the impact of analogues on the sensing performance is mainly due to the π-π interaction between the molecules which hinders binding to suppress response.