A rapid magnetic particle-based enzyme immunoassay for human cytomegalovirus glycoprotein B quantification

Nanomaterials Connected to Bioreceptors to Introduce Efficient Biosensing Strategy for Diagnosis of the TORCH Infections: A Critical Review

TORCH infection is a significant risk factor for severe fetal damage, especially congenital malformations. Screening pregnant women for TORCH pathogens could reduce the incidence of adverse pregnancy outcomes and prevent birth defects. Hence, timely identification and inhibition of TORCH infections are effective ways to successfully prevent them in pregnant women. Recently, the superiority of biosensors in TORCH pathogen sensing has been emphasized due to their intrinsic benefits, such as rapid response time, portability, cost-effectiveness, much friendlier preparation and determination steps. With the introduction of advanced nanomaterials into biosensing, the diagnostic properties of biosensors have significantly improved. This study core presents and debates the current progress in biosensing systems for TORCH pathogens using various artificial and natural receptors. The incorporation of nanomaterials into various transduction systems can enhance diagnostic performance. The key performance characteristics of optical and electrochemical biosensors, such as response time, limit of detection (LOD), and linear detection range, are systematically discussed, along with the current TORCH pathogens used for constructing biosensors. Finally, the major problems that exist for converting scientific investigation into product development are also outlined.

Microelectromechanical system-based biosensor for label-free detection of human cytomegalovirus

The human cytomegalovirus (HCMV) is an asymptomatic common virus that is typically harmless, but in some cases, it can be life threatening. Thus, there is an urgent need to develop novel diagnostic methods and strengthen the efforts to combat this virus. A microcantilever-based biosensor functionalised with the UL83-antibody of HCMV (UL83-HCMV antibody) has been developed to detect the UL83-antigen of HCMV (UL83-HCMV antigen) at different concentrations ranging from 0.3 to 300 ng/ml. The response of the biosensor to the presence of UL83-HCMV antigen was measured through the shift in resonance frequency before and after antigen-antibody binding. The system shows a low detection limit of 84 pg/ml, which is comparable to traditional sensors, and a detection time of less than 15 min was achieved. The selectivity of the sensor was demonstrated using three different proteins with and without the UL83-HCMV antigen. The biosensor shows high selectivity for the UL83-HCMV antigen. Mass loading by the UL83-HCMV antigen was roughly estimated with a sensitivity of ∼30 fg/Hz. This technique is crucial for the fabrication of portable and low-cost biosensors that can be used in real-time monitoring and enables early medical diagnosis.

Pump-Free Microfluidic Device for the Electrochemical Detection of α1-Acid Glycoprotein

α₁-Acid glycoprotein (AGP) is a glycoprotein present in serum, which is associated with the modulation of the immune system in response to stress or injuries, and a biomarker for inflammatory diseases and cancers. Here, we propose a pump-free microfluidic device for the electrochemical determination of AGP. The microfluidic device utilizes capillary-driven flow and a passive mixing system to label the AGP with the Os (VI) complex (an electrochemical tag) inside the main channel, before delivering the products to the electrode surface. Furthermore, thanks to the resulting geometry, all the analytical steps can be carried out inside the device: labeling, washing, and detection by adsorptive transfer stripping square wave voltammetry. The microfluidic device exhibited a linear range from 500 to 2000 mg L^-1 (R² = 0.990) and adequate limit of detection (LOD = 231 mg L^-1). Commercial serum samples were analyzed to demonstrate the success of the method, yielding recoveries around 83%. Due to its simplicity, low sample consumption, low cost, short analysis time, disposability, and portability, the proposed method can serve as a point-of-care/need testing device for AGP.

Kwakhurin-magnetic particles conjugates enable fast enzyme immunoassay for the detection of kwakhurin in Pueraria candollei

INTRODUCTION

Kwakhurin (Kwa) is one of the unique isoflavonoids produced in Pueraria candollei var. mirifica (P. candollei), which has long been used as folk medicine for rejuvenation in Thailand. Recently, the use of P. candollei-derived products has widely spread among Japanese women for cosmetic purposes. Correspondingly, there has been an increase in the number of reports regarding possible health hazards caused by estrogenic activity inherent to the plant; thus, the need for a detailed evaluation of the phytoestrogen content of P. candollei-derived products has gained a sense of urgency in recent years.

OBJECTIVE

This study aims to develop a rapid enzyme immunoassay that can be applied to the quantitative analysis of Kwa in P. candollei and its derived products.

MATERIAL AND METHOD

A rapid and sensitive immunoassay was developed with a combination of Kwa-specific monoclonal antibody (MAb 11F) and Kwa-magnetic particles (MPs) conjugates, which increased the surface area of the solid phase, resulting in a decrease in the immunoreaction time.

RESULT

This novel MPs-based enzyme immunoassay (MPs-EIA) was used to determine Kwa concentration in the range from 2.44 to 78.1 ng/mL with a limit of detection of 1.90 ng/mL. Validation analyses revealed that the proposed MPs-EIA protocol was sufficiently precise and accurate for effective quantitative analysis of Kwa in P. candollei and its derived products.

Nanoparticle Reservoirs for Paper-Only Immunosensors

Biosensors made entirely of paper are becoming increasingly popular due to their low cost, facile fabrication, and lightweight portability for in-field measurements. However, it is difficult to store nanoparticles in paper substrates without irreversibly binding them to the cellulose matrix. This makes it challenging to fabricate biosensors incorporating nanoparticle probes in paper-based reservoirs. Here, we overcome this limitation with a new method for storing protein-decorated nanoparticles on paper substrates that also allows to release them on demand. It consists of spotting nanoparticles onto pieces of filter paper previously modified with polystyrene sulfonate. Gold nanoparticles modified with avidin or antibodies can be easily transferred from the dry reservoir to a receiving wet piece of paper by simply pressing with the finger or a clamp. Paper-based immunosensors incorporating the reservoir enabled the detection of glycoprotein B from human cytomegalovirus in serum with a limit of detection of 0.03 ng mL^-1 and a total assay time of only 12 min. The low limit of detection obtained with a short assay time along with the long shelf-life of the reservoirs make the proposed paper-only biosensors ideal of point-of-care diagnostics.

Facile synthesis of boronic acid-decorated carbon nanodots as optical nanoprobes for glycoprotein sensing

In this article, we proposed new nitrogen-doped boronic acid-decorated carbon nanodots (CNDs) for the recognition and detection of glycoproteins. These doped, decorated CNDs were obtained by a one-step hydrothermal carbonization method using phenylboronic acid and ethylenediamine as precursors. Compared to traditional synthesized and then functionalized nanoscale sensing systems, this method is more facile and efficient. The as-prepared nitrogen-doped CNDs possessed a quasi-spherical morphology and a high quantum yield of approximately 14.5%. The added glycoproteins (taking horseradish peroxidase as a model protein) can selectively induce the assembly and fluorescence quenching of CNDs through the formation of cyclic boronate esters, because the boronic acid groups on the CND surfaces can covalently interact with cis-diol-containing glycoproteins. These fluorescence responses can be used to properly quantify horseradish peroxidase in the range of 3.3-333.3 μg mL-1 with a detection limit of 0.52 μg mL-1, and the selectivity assay with functionalized CNDs was further investigated using various proteins with different quantities of glycosylation sites as well as using smaller molecules. The results show that the nanosensing system possesses favorable selectivity. Due to its simplicity and effectiveness, the system has great application prospects as a practical platform for glycoprotein sensing.