A dual-functional module cellular electrochemical sensing platform for simultaneous detection guanine and xanthine.

The separation of the superimposed electrochemical signals of intracellular guanine (G) and xanthine (X) is difficult, which is great obstacle to the application of cell electrochemistry. In this paper, independent functional modules, G-functional module (G-FM) and X-functional module (X-FM), were constructed by molecular imprinting technology for sensitive detection of G and X without mutual interference, then integrated in dual-functional module cellular electrochemical sensing platform (DMCEP) as signal sensing units. DMCEP transmitted signals of G and X in cells synchronously to two windows by two signal sensing channels, and achieved the separation of superimposed signals of G and X in cells. DMCEP exhibited satisfactory reproducibility with relative standard deviation (RSD) of 3.10 and 2.22 %, repeatability with RSD of 3.72 and 3.05 % for G and X detection, and detection limit 0.05 µΜ for G and 0.06 µΜ for X. Good linear relationships between cell concentrations and the signals of G and X on DMCEP were shown in range of 0.75-85 × 106 and 3-85 × 106 cells/mL, respectively. The growth of MCF-7 cells was tracked by DMCEP, and showed consistent trend with the cell counting method, while the change of cell viability from lag to logarithmic phase captured by DMCEP was earlier than that of cell counting method. This strategy provided the foundation for the establishment of the cell viability electrochemical detection method, and new insights into the simultaneous recording of other analyses with superimposed peak positions and the simultaneous tracking of multiple biomarkers.

Highly Selective Aptamer-Molecularly Imprinted Polymer Hybrids for Recognition of SARS-CoV-2 Spike Protein Variants.

Virus recognition has been driven to the forefront of molecular recognition research due to the COVID-19 pandemic. Development of highly sensitive recognition elements, both natural and synthetic is critical to facing such a global issue. However, as viruses mutate, it is possible for their recognition to wane through changes in the target substrate, which can lead to detection avoidance and increased false negatives. Likewise, the ability to detect specific variants is of great interest for clinical analysis of all viruses. Here, a hybrid aptamer-molecularly imprinted polymer (aptaMIP), that maintains selective recognition for the spike protein template across various mutations, while improving performance over individual aptamer or MIP components (which themselves demonstrate excellent performance). The aptaMIP exhibits an equilibrium dissociation constant of 1.61 nM toward its template which matches or exceeds published examples of imprinting of the spike protein. The work here demonstrates that "fixing" the aptamer within a polymeric scaffold increases its capability to selectivity recognize its original target and points toward a methodology that will allow variant selective molecular recognition with exceptional affinity.

Rational Development of Hypervalent Glycan Shield-Binding Nanoparticles with Broad-Spectrum Inhibition against Fatal Viruses Including SARS-CoV-2 Variants.

Infectious virus diseases, particularly coronavirus disease 2019, have posed a severe threat to public health, whereas the developed therapeutic and prophylactic strategies are seriously challenged by viral evolution and mutation. Therefore, broad-spectrum inhibitors of viruses are highly demanded. Herein, an unprecedented antiviral strategy is reported, targeting the viral glycan shields with hypervalent mannose-binding nanoparticles. The nanoparticles exhibit a unique double-punch mechanism, being capable of not only blocking the virus-receptor interaction but also inducing viral aggregation, thereby allowing for inhibiting the virus entry and facilitating the phagocytosis of viruses. The nanoparticles exhibit potent and broad-spectrum antiviral efficacy to multiple pseudoviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its major variants (D614G, N501Y, N439K, Δ69-70, Delta, and Omicron; lentiviruses expressing only the spike proteins), as well as other vital viruses (human immunodeficiency virus 1 and Lassa virus), with apparent EC50 values around the 10-9  m level. Significantly, the broad-spectrum inhibition of authentic viruses of both wild-type SARS-CoV-2 and Delta variants is confirmed. Therefore, this hypervalent glycan-shield targeting strategy opens new access to broad-spectrum viral inhibition.

Molecularly imprinted miniature electrochemical biosensor for SARS-CoV-2 spike protein based on Au nanoparticles and reduced graphene oxide modified acupuncture needle.

Accurate detection of SARS-CoV-2 spike (SARS-CoV-2-S) protein is of clinical significance for early diagnosis and timely treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Herein, a surface molecularly imprinted miniature biosensor was fabricated. Au nanoparticles (AuNPs), reduced graphene oxide (rGO), poly(methylene blue)/poly(ionic liquids) and poly(ionic liquids) were successively electrodeposited onto the pinpoint of an acupuncture needle (AN). The molecularly imprinted miniature biosensor was obtained after the template of SARS-CoV-2-S protein was removed, which could be used for sensitive detection of SARS-CoV-2-S protein. The linear range and limit of detection (LOD) were 0.1 âˆ¼ 1000 ng mL-1 and 38 pg mL-1, respectively, which were superior to other molecularly imprinted biosensors previously reported. The developed miniature biosensor also exhibited high specificity and stability. The reliability of the biosensor was evaluated by the detection of SARS-CoV-2-S protein in clinical serum samples.

Protein-imprinted particles for coronavirus capture from solution.

Molecular imprinting is a promising strategy to selectively adsorb viruses, but it requires discerning and validating epitopes that serve as effective imprinting templates. In this work, glycoprotein-imprinted particles were synthesized for coronavirus capture. Adsorption was maximized at pH 6 (the glycoprotein isoelectric point) where the glycoprotein-imprinted particles outperformed non-imprinted particles, adsorbing 4.96 × 106  ± 3.33 × 103 versus 3.54 × 106  ± 1.39 × 106 median tissue culture infectious dose/mg of the target coronavirus, human coronavirus - organ culture 43, within the first 30 min (p = 0.012). During competitive adsorption, with pH adjustment (pH 6), the glycoprotein-imprinted particles adsorbed more target virus than non-target coronavirus (human coronavirus - Netherland 63) with 2.34 versus 1.94 log removal in 90 min (p < 0.01). In contrast, the non-imprinted particles showed no significant difference in target versus non-target virus removal. Electrostatic potential calculation shows that the human coronavirus - organ culture 43 glycoprotein has positively charged pockets at pH 6, which may facilitate adsorption at lower pH values. Therefore, tuning the target virus glycoprotein charge via pH adjustment enhanced adsorption by minimizing repulsive electrostatic interactions with the particles. Overall, these results highlight the effective use of glycoprotein-imprinted particles for coronavirus capture and discern the merits and limitations of glycoprotein imprinting for the capture of enveloped viruses.

Unraveling the mystery of efficacy in Chinese medicine formula: New approaches and technologies for research on pharmacodynamic substances.

Traditional Chinese medicine (TCM) is the key to unlock treasures of Chinese civilization. TCM and its compound play a beneficial role in medical activities to cure diseases, especially in major public health events such as novel coronavirus epidemics across the globe. The chemical composition in Chinese medicine formula is complex and diverse, but their effective substances resemble "mystery boxes". Revealing their active ingredients and their mechanisms of action has become focal point and difficulty of research for herbalists. Although the existing research methods are numerous and constantly updated iteratively, there is remain a lack of prospective reviews. Hence, this paper provides a comprehensive account of existing new approaches and technologies based on previous studies with an in vitro to in vivo perspective. In addition, the bottlenecks of studies on Chinese medicine formula effective substances are also revealed. Especially, we look ahead to new perspectives, technologies and applications for its future development. This work reviews based on new perspectives to open horizons for the future research. Consequently, herbal compounding pharmaceutical substances study should carry on the essence of TCM while pursuing innovations in the field.

Differential Refractometric Biosensor for Reliable Human IgG Detection: Proof of Concept.

A new sensing platform based on long-period fiber gratings (LPFGs) for direct, fast, and selective detection of human immunoglobulin G (IgG; Mw = 150 KDa) was developed and characterized. The transducer's high selectivity is based on the specific interaction of a molecularly imprinted polymer (MIPs) design for IgG detection. The sensing scheme is based on differential refractometric measurements, including a correction system based on a non-imprinted polymer (NIP)-coated LPFG, allowing reliable and more sensitive measurements, improving the rejection of false positives in around 30%. The molecular imprinted binding sites were performed on the surface of a LPFG with a sensitivity of about 130 nm/RIU and a FOM of 16 RIU-1. The low-cost and easy to build device was tested in a working range from 1 to 100 nmol/L, revealing a limit of detection (LOD) and a sensitivity of 0.25 nmol/L (0.037 µg/mL) and 0.057 nm.L/nmol, respectively. The sensor also successfully differentiates the target analyte from the other abundant elements that are present in the human blood plasma.

Molecularly imprinted spongy columns for Angiotensin(II) recognition from human serum.

Angiotensin II (AngII), the effector peptide of the renin angiotensin system and has an important role in regulating cardiovascular hemodynamics and structure. AngII is an important biomarker for certain diseases that are associated with cardiovascular disorders, i.e., influenza, SARS-CoV-2, tumors, hypertension, etc. However, AngII presents in blood in very low concentrations and they are not stable due to their reactivity, therefore spontaneous detection of AngII is a big challenge. In this study, AngII-imprinted spongy columns (AngII-misc) synthesized for AngII detection from human serum, and characterized by surface area measurements (BET), swelling tests, scanning electron microscopy (SEM), FTIR studies. AngII binding studies were achieved from aqueous environment and maximum binding capacity was found as 0.667 mg/g. It was calculated that the AngII-miscs recognized AngII 8.27 and 14.25 times more selectively than competitor Angiotensin I and Vasopressin molecules. Newly produced AngII-misc binds 60.5 pg/g AngII from crude human serum selectively. It has a great potential for spontaneous detection of AngII from human serum for direct and critical measurements in serious diseases, that is, heart attacks, SARS-CoV-2, etc.

Computational analysis of functional monomers used in molecular imprinting for promising COVID-19 detection.

Today, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has recently caused a severe outbreak worldwide. There are still several challenges in COVID-19 diagnoses, such as limited reagents, equipment, and long turnaround times. In this research, we propose to design molecularly imprinted polymers as a novel approach for the rapid and accurate detection of SARS-CoV-2. For this purpose, we investigated molecular interactions between the target spike protein, receptor-binding domain of the virus, and the common functional monomers used in molecular imprinting by a plethora of computational analyses; sequence analysis, molecular docking, and molecular dynamics (MD) simulations. Our results demonstrated that AMPS and IA monomers gave promising results on the SARS-CoV-2 specific TEIYQAGST sequence for further analysis. Therefore, we propose an epitope approach-based synthesis route for specific recognition of SARS-CoV-2 by using AMPS and IA as functional monomers and the peptide fragment of the TEIYQAGST sequence as a template molecule.