Low-fouling CNT-PEG-hydrogel coated quartz crystal microbalance sensor for saliva glucose detection

Saliva glucose detection based on a quartz crystal microbalance (QCM) sensor has emerged as a promising tool and a non-invasive diagnostic technique for diabetes. However, the low glucose concentration and strong protein interference in the saliva hinder the QCM sensors from practical applications. In this study, we present a robust and simple anti-fouling CNT-PEG-hydrogel film-coated QCM sensor for the detection of saliva glucose with high sensitivity. The CNT-PEG-hydrogel film consists of two layers; the bottom base PBA-hydrogel film is designed to recognize the glucose while the top CNT-PEG layer is used to restrict protein adsorption and improve the biocompatibility. Our results show that this CNT-PEG-hydrogel film exhibited a 10-fold enhancement on the detection limit compared to the PBA-hydrogel. Meanwhile, the adsorption of proteins on the surface of the CNT-PEG-hydrogel film, including bovine serum albumin (BSA), mucin (MUC), and fibrinogen (FIB), were reduced by 99.1%, 77.8%, and 83.7%, respectively. The CNT-PEG-hydrogel film could detect the typical saliva glucose level (0-50 mg L-1) in 10% saliva with a good responsivity. To sum up, this new tool with low-fouling film featuring high stability, specificity, and selectivity holds great potential for non-invasive monitoring of saliva glucose in human physiological levels.

Lost in (Clinical) Translation: Recent Advances in Heparin Neutralization and Monitoring

The heparin family, which includes unfractionated heparin, low-molecular heparin, and fondaparinux, is a class of drugs clinically used as intravenous blood thinners. To date, issues related to both the reversal of anticoagulation and the blood level determination of the anticoagulant at the point-of-care remain: while the only U.S. Food and Drug Administration (FDA) approved antidote for heparin displays serious efficacy and safety drawbacks, the current assays for heparin monitoring are indirect measurements subject to their own limitations and variations. Herein, we provide an update on the numerous recent chemical approaches to tackle these issues, from which it is clear that some new antidotes and sensors for heparin certainly have the potential to exceed current clinical standards. This review aims to review a field that requires close collaborations between physicians, biologists, and chemists in order to foster advances toward clinical translation.

Recent Progress of Imprinted Nanomaterials in Analytical Chemistry

Molecularly imprinted polymers (MIPs) are a type of tailor-made materials that have ability to selectively recognize the target compound/s. MIPs have gained significant research interest in solid-phase extraction, catalysis, and sensor applications due to their unique properties such as low cost, robustness, and high selectivity. In addition, MIPs can be prepared as composite nanomaterials using nanoparticles, multiwalled carbon nanotubes (MWCNTs), nanorods, quantum dots (QDs), graphene, and clays. This review paper aims to demonstrate and highlight the recent progress of the applications of imprinted nanocomposite materials in analytical chemistry.

Synthesis of a series of benzothiazole amide derivatives and their biological evaluation as potent hemostatic agents

A series of benzothiazole amide derivatives were synthesized through a facile and efficient method via a nucleophilic acyl substitution reaction between 2-aminobenzothiazole and various cinnamic acid compounds. The obtained products exhibited good thermal stabilities. All compounds were evaluated for their in vitro hemostatic activities using the commercially available standard drug etamsylate as a positive control. The results showed that compound Q2 had a significant partial coagulation activity, reduced capillary permeability at 5, 10 and 50 μmol L⁻¹, activated thrombin activity, and a more potent platelet aggregation activity than the positive control group (etamsylate, up to 1283.9 times in the nanomole range). A molecular modeling study revealed that compound Q2 was a competitive thrombin activator. Therefore, Q2 may be a potential lead for further biological screening and for the generation of drug molecules. Moreover, the structure–activity relationship of the prepared compounds is also discussed herein.

New benzothiazole amide derivative Q2 is a potential hemostatic drug molecule with good hemostatic activity.

QCM-D surpassing clinical standard for the dose administration of new oral anticoagulant in the patient of coagulation disorders

The study focuses the dose administration of dabigatran to avoid the deaths due to hemorrhagic complications and thromboembolic stroke in clinics worldwide. To target the issue, a novel emerging acoustic technology, namely ''Quartz Crystal Microbalance with Dissipation'' (QCM-D) has been applied, while the acoustic assays namely ''activated Partial Thromboplastin Time'' (aPTT) and ''Prothrombinase complex-induced Clotting Test'' (PiCT) have been compared with the standard methods in parallel. Both techniques have been applied to 300 samples, including 220 plasma samples of patients suffering coagulation disorders and 80 plasma samples of non-patients. In comparison, the coagulation times of the acoustic aPTT and PiCT yielded an excellent correlation with the standard methods with in analytical standard deviation limits. Finally, the acoustic aPTT assay is the ''gold standard'' for a dose administration of the new oral anticoagulant, where the Δf/ΔΓ ratio of the acoustic assay demonstrates that dabigatran with FEIBA 50 combination could be a safe remedy to avoid the deaths in clinics.

Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors

Molecularly imprinted polymers (MIPs) as artificial antibodies have received considerable scientific attention in the past years in the field of (bio)sensors since they have unique features that distinguish them from natural antibodies such as robustness, multiple binding sites, low cost, facile preparation and high stability under extreme operation conditions (higher pH and temperature values, etc.). On the other hand, the Quartz Crystal Microbalance (QCM) is an analytical tool based on the measurement of small mass changes on the sensor surface. QCM sensors are practical and convenient monitoring tools because of their specificity, sensitivity, high accuracy, stability and reproducibility. QCM devices are highly suitable for converting the recognition process achieved using MIP-based memories into a sensor signal. Therefore, the combination of a QCM and MIPs as synthetic receptors enhances the sensitivity through MIP process-based multiplexed binding sites using size, 3D-shape and chemical function having molecular memories of the prepared sensor system toward the target compound to be detected. This review aims to highlight and summarize the recent progress and studies in the field of (bio)sensor systems based on QCMs combined with molecular imprinting technology.

Poly(ethylene glycol acrylate)-functionalized hydrogels for heparan sulfate oligosaccharide recognition

Heparan sulfates are complex polysaccharides belonging to the family of glycosaminoglycans that participate to the regulation of cell behavior and tissue homeostasis. The biological activities conferred to heparan sulfates are largely dependent on the content and positioning of the sulfate groups along their saccharidic units. At present, identification of particular sulfation patterns in biologically relevant heparan sulfate sequences remains challenging. Although several approaches for structure analysis exist, the complexity of heparan sulfates makes new and original approaches still required. Here, we used molecular imprinting technologies to prepare a library of polyethylene glycol acrylate functionalized hydrogels with the aim to investigate their applicability as specific recognizing systems for fondaparinux, a synthetic pentasaccharide analog to the antithrombin binding site of heparin. Adequate choice of the hydrogel composition and controlling rebinding conditions were important determinants for improving the sulfated oligosaccharide recognition specificity and selectivity. Our results suggest that molecular imprinting approaches could be a possibility for the specific recognition of biologically active sequences in heparan sulfates.