Molecularly imprinted polymers as synthetic receptors for the QCM-D-based detection of l-nicotine in diluted saliva and urine samples

Abstract

Molecularly imprinted polymers (MIPs) are synthetic receptors that are able to specifically bind their target molecules in complex samples, making them a versatile tool in biosensor technology. The combination of MIPs as a recognition element with quartz crystal microbalances (QCM-D with dissipation monitoring) gives a straightforward and sensitive device, which can simultaneously measure frequency and dissipation changes. In this work, bulk-polymerized L-nicotine MIPs were used to test the feasibility of L-nicotine detection in saliva and urine samples. First, L-nicotine-spiked saliva and urine were measured after dilution in demineralized water and 0.1× phosphate-buffered saline solution for proof-of-concept purposes. L-nicotine could indeed be detected specifically in the biologically relevant micromolar concentration range. After successfully testing on spiked samples, saliva was analyzed, which was collected during chewing of either nicotine tablets with different concentrations or of smokeless tobacco. The MIPs in combination with QCM-D were able to distinguish clearly between these samples: This proves the functioning of the concept with saliva, which mediates the oral uptake of nicotine as an alternative to the consumption of cigarettes.

Array Formatting of the Heat-Transfer Method (HTM) for the Detection of Small Organic Molecules by Molecularly Imprinted Polymers

“…To correct for the non-specific binding effect the normalized R th of the NIP was subtracted from the R th of the MIP. Previous research [15,17,23] has indicated that this operation facilitates the transition from well controlled buffer solutions to biological samples, such as urine, saliva or blood. Furthermore, external factors such as fluctuations of the environmental temperature, can be cancelled out.…”

“…A novel read-out technique has been proposed to detect small organic molecules and cells with MIP type receptors [23,24]. This heat-transfer method (HTM) eliminates the need of sophisticated equipment since it requires only two thermocouples, a proportional-integral-derivative (PID) controller, an adjustable heat source, and ensures fast detection of a variety of target molecules in buffer solutions.…”

Evaluation of Hyaluronic Acid Dilutions at Different Concentrations Using a Quartz Crystal Resonator (QCR) for the Potential Diagnosis of Arthritic Diseases

“…There are several studies linking the use of the Quartz Crystal Microbalance (QCM) to the detection of diseases characterizing biological fluids as blood [12,13,14,15], urine [16,17], saliva [17,18,19] and synovial fluid [20,21]. The methods proposed in these studies have proven to be successful according to their results.…”

Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors

“…Alenus et al have published two different studies on the detection of l -nicotine. One of the studies is in aqueous solution [26] while the other one is in a biological sample [27]. Although many researchers have studied l -nicotine template molecules in aqueous solution, Alenus et al studied the detection of l -nicotine in saliva and urine.…”