Capture of Phenylalanine and Phenylalanine-Terminated Peptides Using a Supramolecular Macrocycle for Surface-Enhanced Raman Scattering Detection

Capture and Detection of Fentanyl with Thiolated Cucurbit[7]uril Macrocycles on Silver Nanoparticles

“…Indeed, the capture of AdNH 2 using CB [7]-SH here for SERS detection was comparable to that from a prior report using unmodified CB [7]. 22 3.5. Enhancing Fentanyl Limit of Detection.…”

“…As AdNH 2 does not need to fully thread the CB[7] macrocycle to achieve its optimal binding position, the expected benefits of the alternate orientation of covalently tethered CB[7]-SH are less relevant in this context. Indeed, the capture of AdNH 2 using CB[7]-SH here for SERS detection was comparable to that from a prior report using unmodified CB[7] …”

“…This same effect was observed previously when using AdNH 2 to block CB [7] capture-based SERS detection of phenylalanine-terminated peptides, with the higher affinity guest successfully preventing SERS detection. 22 Unfortunately, this was not observed (Figure S13). When fentanyl and AdNH 2 were simultaneously introduced to AgNPs modified with CB [7]-SH, the fentanyl 1002 cm −1 peak and the AdNH 2 779 cm −1 peak were both present in the resultant spectrum.…”

“…Unfortunately, due to the extremely high potency of this drug, the binding affinity of CB[7] is still below the threshold needed to enable sequestration for fentanyl detoxification at lethal drug concentrations occurring in blood, although nascent macrocycles have been reported in recent years that could achieve such affinity . Toward the creation of sensors, CB­[ n ] species can be adsorbed to metal surfaces, affording synthetic receptors that sequester small molecule guests of interest near the metal surface; this feature is of particular relevance for surface-specific techniques like surface-enhanced Raman spectroscopy (SERS) using metal nanoparticle sensors. − By predictably and selectively sequestering guest molecules near a nanoparticle surface, this approach to detector design has the possibility of significantly enhancing the detection limits of otherwise elusive analytes in complicated matrices. In this work, the selective binding of fentanyl-type drugs to CB[7] is explored via competitive NMR studies on drug mixtures, followed by an assessment of the sensing application of a novel thiolated CB[7] macrocycle for anchoring to a silver nanoparticle (AgNPs) substrate for fentanyl detection using SERS (Scheme ).…”

The Cyclobutanocucurbit[5–8]uril Family: Electronegative Cavities in Contrast to Classical Cucurbituril while the Electropositive Outer Surface Acts as a Crystal Packing Driver

“…Cucurbit[ n ]uril (classical Q[ n ], n = 5–8, 10, and 13–15) have been shown to exhibit a wide range of potential applications in various fields, through leveraging the properties of this macrocyclic family and by the selection of a cavity with an appropriate size. Recent examples demonstrate this with targeted cell imaging [ 1 ], human cancer assay [ 2 ], Q[ n ]-based supramolecular frameworks (QSFs) [ 3 , 4 ], sensors [ 5 , 6 , 7 , 8 ], fluorescent imprintable hydrogels [ 9 ], fluorescent probes [ 10 , 11 , 12 ], nitroxide radical probes [ 13 ], the preparation of adsorbent or solid fluorescent materials [ 14 ], room-temperature phosphorescence (RTP) [ 15 , 16 ], light-harvesting systems [ 17 ], nanocapsules [ 18 ], nanofiltration membranes [ 19 ] molecular machines [ 20 , 21 , 22 ] reductive catalysis of CO 2 [ 23 ], and gold recovery [ 24 ].…”