Label-free electrochemical immunosensor for picomolar detection of the cervical cancer biomarker MCM5

Label-free electrochemical immunoassay for ultra-sensitive detection of PSA utilizing gold nanoparticles/polyhedral hollow CoCu bimetallic sulfide nanostructure as a dual signal amplification platform

This study introduces the development of a highly sensitive label-free electrochemical immunosensor specifically designed to detect prostate-specific antigen (PSA). A glassy carbon electrode (GCE) coated with Au nanoparticles/polyhedral hollow CoCu bimetallic sulfide (CuCo2S4) was employed as a sensing interface for the fixation of the monoclonal anti-PSA antibody. The nanoarchitectures enhanced the capacity for loading prostate-specific antibodies (Ab) and effectually boosted electrical conductivity leading to enhance the electrochemical signal and greater sensitivity for the detection of PSA. The electrochemical behavior of the engineered sensor was researched via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The response of the fabricated immunosensor manifested a linearized correlation with PSA concentration, spanning from 50.0 fg/ml to 500.0 ng/ml, with a minimal detection limit (DPV: 19.0 fg/ml, EIS: 14.0 fg/ml) and superior stability. The morphological and structural features of the engineered nanomaterials were analyzed using a range of techniques, including field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The proposed immunosensor was utilized for the meticulous and ultra-sensitive analysis of PSA levels in serum specimens, providing results that align satisfactorily with those from the enzyme-linked immunosorbent assay (ELISA) the benchmark protocol. In conclusion, these outcomes underscore the potential utility of the developed immunosensor for prostate cancer screening in its initial stages.

Advances in human papillomavirus detection for cervical cancer screening and diagnosis: challenges of conventional methods and opportunities for emergent tools

Human papillomavirus (HPV) infection is the main cause of cervical cancer and other cancers such as anogenital and oropharyngeal cancers. The prevention screening and treatment of cervical cancer has remained one of the top priorities of the World Health Organization (WHO). In 2020, the WHO came up with the 90-70-90 strategy aimed at eliminating cervical cancers as a public health problem by the year 2030. One of the key priorities of this strategy is the recommendation for countries to ensure that 70% of their women are screened using a high-performance test by the age of 35, and again by the age of 45. Over the years, several traditional methods (notably, Pap smear and nucleic acid-based techniques) have been used for the detection of cervical cancer. While these methods have significantly reduced the incidence of cervical cancer and death, they still come short of excellence for the total eradication of HPV infection. The challenges include low sensitivity, low specificity, poor reproducibility, the need for high-level specialists, and the high cost of access to the facilities, to mention a few. Interestingly, however, several efforts are being made today to mitigate these challenges. In this review, we discussed the pros and cons of the traditional screening and testing of HPV infections, the efforts being made to improve their performances, and the emergent tools (especially, the electrochemical methods) that promise to revolutionize the screening and testing of HPV infections. The main aim of the review is to provide some novel clues to researchers that would allow for the development of high-performance, affordable, and triage-suitable electrochemical-based diagnostic tools for HPV and cervical cancer.

Electrochemical detection of cervical cancer biomarkers

Cervical cancer (CC) is the fourth most common cancer among women worldwide, following breast, colorectal, and lung cancers. Each year, it accounts for approximately 600,000 new cases and 340,000 deaths. Early-stage cervical cancer is treatable with surgery and chemoradiotherapy (CCRT). However, treatment for metastatic cervical cancer is limited, with bevacizumab combined with chemotherapy being one of the few options, though survival rates remain low. Currently, the diagnosis of cervical cancer primarily relies on Pap smears and colposcopy. Although these methods are essential for detection, they are costly, labor-intensive, and require significant resources. Therefore, there is an urgent need to identify effective biomarkers that can detect cervical cancer at an early stage, improving both the accuracy of diagnosis and the efficacy of treatment. Although numerous cervical cancer biomarkers have been identified for the cervical cancer thanks to advances in technology. In recent times, electrochemical methods have proven to be particularly effective in cervical cancer detection. In this paper, we reviewed the important cervical cancer biomarkers and their detection through electrochemical biosensors, which offer advantages such as higher sensitivity, affordability, and ease of analysis. Furthermore, we discussed the limitations and future prospects of electrochemical biosensors in this field.

A bio-nano-engineered platform fabricated from cerium oxide-carbon nanoparticles stabilized with chitosan for label-free sensing of a lung cancer biomarker

Herein, we report a label-free cancer biosensor designed for carcinoembryonic antigen (CEA) detection using a nanohybrid comprising CeO2 nanoparticles, carbon nanoparticles (CNPs), and chitosan (Ch). CeO2 nanoparticles were prepared using a simple green synthesis process. A thin film of the CeO2-CNPs-Ch nanohybrid was formed on indium tin oxide (ITO)-coated glass plates that endowed a high surface area, excellent stability, and good adsorption for the efficient loading of CEA antibodies. Quantitative and selective determination of CEA antigen was achieved by immobilizing monoclonal CEA antibodies (anti-CEA) on the CeO2-CNPs-Ch/ITO platform. The electrochemical response of the anti-CEA/CeO2-CNPs-Ch/ITO immunoelectrode was evaluated in a label-free immunoassay format using differential pulse voltammetry (DPV). The response studies of immunoelectrodes indicated wider linearity with respect to the CEA concentration in the range of 0.05-100 ng mL-1. The electrochemical cancer biosensor exhibited a higher sensitivity of 22.40 μA cm-2 per decade change in concentration along with storage stability for up to 35 days. The limit of detection (LOD) was 0.037 ng mL-1. Furthermore, this cancer biosensor exhibited good specificity and reproducibility. Thus, the proposed CeO2-CNPs-Ch nanocomposite-based platform provides an efficient method for the analysis of other antigen-antibody interactions and biomolecule detection. The efficacy of the anti-CEA/CeO2-CNPs-Ch/ITO immunoelectrode was further examined by measuring CEA levels in human serum.

Reagent-free anti-fouling electrochemical immunosensor based on AL-BSA/AuNPs/PANI coating for the point-of-care detection of C-reactive protein in plasma and whole blood

Developing the portable CRP detection technologies that are suitable for point-of-care (POC) and primary care management is of utmost importance, and advancing the electrochemical immunosensors hold promise for POC implementation. Nevertheless, non-specific adsorption of numerous interfering proteins in complex biological media contaminates immunosensors, thereby restricting the reliability in detection efficacy. In this study, a three-dimensional flower-leaf shape amyloid bovine serum albumin/gold nanoparticles/polyaniline (AL-BSA/AuNPs/PANI) coating on the surface of the electrode was developed, which demonstrated strong anti-adsorption properties against bovine serum albumin, plasma, and cells. The immunosensor exhibited a good linear relationship to CRP response, featuring a detection limit of 0.09 μg/mL, consistent with clinical reference range. In addition, the CRP immunosensor demonstrated excellent specificity in other inflammation-related proteins and commendable anti-interference performance for CRP detection in plasma and whole blood tests. Importantly, by combining the development of a USB flash disk-type portable electrochemical workstation with a reagent-free mode, the developed CRP electrochemical immunosensor delivered ideal results in clinical samples. The anti-fouling performance, sensitivity and specificity of the immunosensor, as well as its flexible test modes in clinical samples, provide important scientific basis for developing POC detection technologies of vital biomarkers in complex biological media.

Techniques for characterizing biofunctionalized surfaces for bioanalysis purposes

Surface biofunctionalization is an essential stage in the preparation of any bioassay affecting its analytical performance. However, a complete characterization of the biofunctionalized surface, considering studies of coverage density, distribution and orientation of biomolecules, layer thickness, and target biorecognition efficiency, is not met most of the time. This review is a critical overview of the main techniques and strategies used for characterizing biofunctionalized surfaces and the process in between. Emphasis is given to scanning force microscopies as the most versatile and suitable tools to evaluate the quality of the biofunctionalized surfaces in real-time dynamic experiments, highlighting the helpful of atomic force microscopy, Kelvin probe force microscopy, electrochemical atomic force microscopy and photo-induced force microscopy. Other techniques such as optical and electronic microscopies, quartz crystal microbalance, X-ray photoelectron spectroscopy, contact angle, and electrochemical techniques, are also discussed regarding their advantages and disadvantages in addressing the whole characterization of the biomodified surface. Scarce reviews point out the importance of practicing an entire characterization of the biofunctionalized surfaces. This is the first review that embraces this topic discussing a wide variety of characterization tools applied in any bioanalysis platform developed to detect both clinical and environmental analytes. This survey provides information to the analysts on the applications, strengths, and weaknesses of the techniques discussed here to extract fruitful insights from them. The aim is to prompt and help the analysts to accomplish an entire assessment of the biofunctionalized surface, and profit from the information obtained to enhance the bioanalysis output.

An updated landscape on nanotechnology-based drug delivery, immunotherapy, vaccinations, imaging, and biomarker detections for cancers: recent trends and future directions with clinical success

The recent development of nanotechnology-based formulations improved the diagnostics and therapies for various diseases including cancer where lack of specificity, high cytotoxicity with various side effects, poor biocompatibility, and increasing cases of multi-drug resistance are the major limitations of existing chemotherapy. Nanoparticle-based drug delivery enhances the stability and bioavailability of many drugs, thereby increasing tissue penetration and targeted delivery with improved efficacy against the tumour cells. Easy surface functionalization and encapsulation properties allow various antigens and tumour cell lysates to be delivered in the form of nanovaccines with improved immune response. The nanoparticles (NPs) due to their smaller size and associated optical, physical, and mechanical properties have evolved as biosensors with high sensitivity and specificity for the detection of various markers including nucleic acids, protein/antigens, small metabolites, etc. This review gives, initially, a concise update on drug delivery using different nanoscale platforms like liposomes, dendrimers, polymeric & various metallic NPs, hydrogels, microneedles, nanofibres, nanoemulsions, etc. Drug delivery with recent technologies like quantum dots (QDs), carbon nanotubes (CNTs), protein, and upconverting NPs was updated, thereafter. We also summarized the recent progress in vaccination strategy, immunotherapy involving immune checkpoint inhibitors, and biomarker detection for various cancers based on nanoplatforms. At last, we gave a detailed picture of the current nanomedicines in clinical trials and their possible success along with the existing approved ones. In short, this review provides an updated complete landscape of applications of wide NP-based drug delivery, vaccinations, immunotherapy, biomarker detection & imaging for various cancers with a predicted future of nanomedicines that are in clinical trials.

Comparative study of electrochemical-based sensors and immunosensors in terms of advantageous features for detection of cancer biomarkers

Cancer, becoming increasingly common globally, has a high mortality rate. Despite the much research on diagnosis and treatment methods, the benefits of technological developments, and newly developed sensor devices, cancer is still one of the leading causes of death worldwide. Early detection using powerful and noninvasive tools could be a future focus for prognosis and treatment follow-up. Therefore, electrochemical biosensors can be a strong choice for the detection of cancer biomarkers (such as alpha-fetoprotein, cytochrome c, prostate-specific antigen, myoglobin, carcinoembryonic antigen, alpha-fetoprotein, a cancer antigen, epidermal growth factor receptor, vascular endothelial growth factor, circulating tumor cell, and breast cancer antigen 1/2) due to their advantages such as high sensitivity, excellent selectivity, low cost, short analysis time, and simplicity. Furthermore, electrochemical biosensors are better suited for point-of-care applications due to their mass production and miniaturization ease. This review provides an overview of different electrochemical measurement techniques, bioreceptor surfaces, signal production and amplification, and the integration of electrochemical-modified sensors. Cancer biomarkers based on electrochemical biosensors were given in detail. In addition, studies with MIP-based sensors and immunosensors have been extensively discussed. Integrating electrochemical biosensors with cancer biomarkers was also emphasized as a new research trend. Finally, we provide an overview of current advances in measuring and analyzing cancer biomarkers using electrochemical biosensors and detail current challenges and future perspectives.

DNA replication: Mechanisms and therapeutic interventions for diseases

Accurate and integral cellular DNA replication is modulated by multiple replication-associated proteins, which is fundamental to preserve genome stability. Furthermore, replication proteins cooperate with multiple DNA damage factors to deal with replication stress through mechanisms beyond their role in replication. Cancer cells with chronic replication stress exhibit aberrant DNA replication and DNA damage response, providing an exploitable therapeutic target in tumors. Numerous evidence has indicated that posttranslational modifications (PTMs) of replication proteins present distinct functions in DNA replication and respond to replication stress. In addition, abundant replication proteins are involved in tumorigenesis and development, which act as diagnostic and prognostic biomarkers in some tumors, implying these proteins act as therapeutic targets in clinical. Replication-target cancer therapy emerges as the times require. In this context, we outline the current investigation of the DNA replication mechanism, and simultaneously enumerate the aberrant expression of replication proteins as hallmark for various diseases, revealing their therapeutic potential for target therapy. Meanwhile, we also discuss current observations that the novel PTM of replication proteins in response to replication stress, which seems to be a promising strategy to eliminate diseases.

Non-Enzymatic Phenylboronic Acid-Based Optode Membrane for Glucose Monitoring in Serums of Diabetic Patients and in the Culture Medium of Human Embryos

Monitoring glucose levels is important not only for diabetics, but also for tracking embryonic development in human embryo culture media. In this study, an optochemical sensor (glucose-selective polymer membrane) was fabricated for the determination of glucose in serum from diabetic patients and the culture media of human embryos. The optode membranes were formulated using polyvinyl chloride (PVC) as the polymer matrix and 4',5'-dibromofluorescein octadecyl ester (ETH 7075) as the chromoionophore. The sensitivity of the optode membranes was optimized using two different plasticizers (tricresyl phosphate-TCP and nitrophenyloctyl ether-NOPE) and three ionophores (nitrophenylboronic acid-NPBA, trifluorophenyboronic acid-TFPBA, 4'-nitrobenzo-15-crown-5) and tested for glucose detection. The best optode membrane was formulated from 49.5% PVC, 49.5% TCP, 1% NPBA, and 1% ETH 7075. It showed a linear dynamic range of 10^-3 M to 10^-1 M, with a detection limit of 9 × 10^-4 M and a response time of 2 min. The detection mechanism involves H-bonding between NPBA and glucose, which was confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR). The reaction also involves the formation of boronate esters in basic media with deprotonation of the chromoionophore (ETH 7075), leading to a decrease in UV-Vis absorbance at λmax = 530 nm. The membrane optode was used for glucose determination in synthetic culture medium, commercial embryo culture medium (GLOBAL^® TOTAL^® W/HEPES), and serum from normal and diabetic patients, showing good accuracy and precision of the optode.

Nanoparticle and Nanostructure Synthesis and Controlled Growth Methods

Nanomaterials are materials with one or more nanoscale dimensions (internal or external) (i.e., 1 to 100 nm). The nanomaterial shape, size, porosity, surface chemistry, and composition are controlled at the nanoscale, and this offers interesting properties compared with bulk materials. This review describes how nanomaterials are classified, their fabrication, functionalization techniques, and growth-controlled mechanisms. First, the history of nanomaterials is summarized and then the different classification methods, based on their dimensionality (0-3D), composition (carbon, inorganic, organic, and hybrids), origin (natural, incidental, engineered, bioinspired), crystal phase (single phase, multiphase), and dispersion state (dispersed or aggregated), are presented. Then, the synthesis methods are discussed and classified in function of the starting material (bottom-up and top-down), reaction phase (gas, plasma, liquid, and solid), and nature of the dispersing forces (mechanical, physical, chemical, physicochemical, and biological). Finally, the challenges in synthesizing nanomaterials for research and commercial use are highlighted.