Bio-functionalized magnetic nanoparticles for the immunoassay of fetal fibronectin: a feasibility study for the prediction of preterm birth

Gelatin-Coated Magnetic Nanowires for High-Sensitivity Optical Labels

The encapsulation of magnetic nickel nanowires (NiNWs) with gelatin is proposed as an alternative for optical label detection. Magnetic nanowires can be detected at very low concentrations using light-scattering methods. This detection capacity could be helpful in applications such as transducers for molecular and biomolecular sensors; however, potential applications require the attachment of specific binding molecules to the nanowire structure. In the present study, a method is presented which is helpful in coating magnetic nanowires with gelatin, a material with the potential to handle specific decoration and functionalization of the nanowires; in the first case, silver nanoparticles (AgNPs) are efficiently used to decorate the nanowires. Furthermore, it is shown that the synthesized gelatin-coated particles have excellent detectability to the level of 140 pg/mL; this level of detection outperforms more complex techniques such as ICP-OES (~3 ng/mL for Ni) and magnetoresistance sensing (~10 ng/mL for magnetic nanoparticles).

Nanotechnologies in Obstetrics and Cancer during Pregnancy: A Narrative Review

Nanotechnology, the art of engineering structures on a molecular level, offers the opportunity to implement new strategies for the diagnosis and management of pregnancy-related disorders. This review aims to summarize the current state of nanotechnology in obstetrics and cancer in pregnancy, focusing on existing and potential applications, and provides insights on safety and future directions. A systematic and comprehensive literature assessment was performed, querying the following databases: PubMed/Medline, Scopus, and Endbase. The databases were searched from their inception to 22 March 2022. Five independent reviewers screened the items and extracted those which were more pertinent within the scope of this review. Although nanotechnology has been on the bench for many years, most of the studies in obstetrics are preclinical. Ongoing research spans from the development of diagnostic tools, including optimized strategies to selectively confine contrast agents in the maternal bloodstream and approaches to improve diagnostics tests to be used in obstetrics, to the synthesis of innovative delivery nanosystems for therapeutic interventions. Using nanotechnology to achieve spatial and temporal control over the delivery of therapeutic agents (e.g., commonly used drugs, more recently defined formulations, or gene therapy-based approaches) offers significant advantages, including the possibility to target specific cells/tissues of interest (e.g., the maternal bloodstream, uterus wall, or fetal compartment). This characteristic of nanotechnology-driven therapy reduces side effects and the amount of therapeutic agent used. However, nanotoxicology appears to be a significant obstacle to adopting these technologies in clinical therapeutic praxis. Further research is needed in order to improve these techniques, as they have tremendous potential to improve the accuracy of the tests applied in clinical praxis. This review showed the increasing interest in nanotechnology applications in obstetrics disorders and pregnancy-related pathologies to improve the diagnostic algorithms, monitor pregnancy-related diseases, and implement new treatment strategies.

Multifunctional Iron Oxide Magnetic Nanoparticles for Biomedical Applications: A Review

Due to their good magnetic properties, excellent biocompatibility, and low price, magnetic iron oxide nanoparticles (IONPs) are the most commonly used magnetic nanomaterials and have been extensively explored in biomedical applications. Although magnetic IONPs can be used for a variety of applications in biomedicine, most practical applications require IONP-based platforms that can perform several tasks in parallel. Thus, appropriate engineering and integration of magnetic IONPs with different classes of organic and inorganic materials can produce multifunctional nanoplatforms that can perform several functions simultaneously, allowing their application in a broad spectrum of biomedical fields. This review article summarizes the fabrication of current composite nanoplatforms based on integration of magnetic IONPs with organic dyes, biomolecules (e.g., lipids, DNAs, aptamers, and antibodies), quantum dots, noble metal NPs, and stimuli-responsive polymers. We also highlight the recent technological advances achieved from such integrated multifunctional platforms and their potential use in biomedical applications, including dual-mode imaging for biomolecule detection, targeted drug delivery, photodynamic therapy, chemotherapy, and magnetic hyperthermia therapy.

Bio-Functionalized Magnetic Nanoparticles for the Immunoassay of C-Reactive Protein and Procalcitonin in Cervicovaginal Secretions of Pregnant Women with Preterm Prelabor Rupture of Membranes to Predict Early-Onset Neonatal Sepsis

Purpose

Early-onset sepsis is a major cause of neonatal morbidity and mortality. C-reactive protein (CRP) and procalcitonin (PCT) are acute phase reactants related to infection. The aim of this study was to explore the feasibility of measuring CRP and PCT concentrations in cervicovaginal secretions of pregnant women with preterm prelabor rupture of membranes (PPROM) using an immunomagnetic reduction (IMR) assay to predict early-onset neonatal sepsis.

Patients and Methods

This prospective study was performed at Mackay Memorial Hospital, Taipei, Taiwan from February 2015 to January 2018. Pregnant women with PPROM between 22 and 34 weeks of gestation were recruited. CRP and PCT concentrations in cervicovaginal secretions were measured using an IMR assay.

Results

Thirty-five cervicovaginal secretion samples were obtained. After excluding two neonatal deaths, early-onset neonatal sepsis was diagnosed in 15 of the 33 surviving neonates. There was no significant relationship between cervicovaginal secretion CRP level and neonatal sepsis; however, cervicovaginal secretion PCT levels were significantly higher in the neonatal sepsis group than in the non-sepsis group (45.99 vs 9.54 ng/mL, P = 0.039). Receiver operating characteristic (ROC) curve analysis revealed a PCT cut-off level of 20.60 ng/mL to predict early-onset sepsis, and the area under the ROC curve was 0.71 (95% confidence interval 0.52 to 0.90, P = 0.039), with sensitivity and specificity of 73.3% and 77.8%, respectively.

Conclusion

Measuring the concentration of PCT in cervicovaginal secretions with an IMR assay can predict early-onset sepsis in neonates born to mothers with PPROM.

Immunofluorescence Assay Using Monoclonal and Polyclonal Antibodies for Detection of Staphylococcal Enterotoxins A in Milk

Objectives:

Staphylococcus aureus is a Gram-positive microorganism. S. aureus can grow in various foods and cause food poisoning by secreting enterotoxins. The most common enterotoxins involved in food poisoning are staphylococcal enterotoxin A and staphylococcal enterotoxin B, but Staphylococcal Enterotoxin A (SEA) is predominant. The main types of food contaminated with SEs are meat and meat products, poultry and eggs, milk and dairy products. The aim of this study was to develop a rapid and sensitive fluorescence immunoassay for detection of staphylococcal enterotoxin A in milk.

Methods:

Monoclonal and polyclonal antibodies for SEA were produced and characterized. Competitive fluorescence immunoassay based on Magnetic Nanoparticles (MNPs) was performed and optimized. MNPs were used as a solid carrier of the antibodies. The first step of the assay was immunoreaction between the immobilized antibody onto MNPs and SEA in milk sample. Then the fluorescein-SEA conjugate was added to the sample. Thus, competitive immunoreaction between MNP-mAb/MNP-pAb with SEA and SEA-FITC was performed. These immuno-complexes were separated by a magnetic separator and the obtained supernatants were analyzed. The fluorescent signal from the excess of conjugated SEA was proportional to the SEA contained in the milk. The assay duration was only 30 min.

Results:

The fluorescence immunoassays performed with polyclonal antibody had linear ranges from 5 pg/mL to 100 ng/mL SEA in a buffer, and from 50 pg/mL to 50 ng/mL SEA in spiked milk samples. While the same assays performed with monoclonal antibody had linear ranges from 1 pg/mL to 20 ng/mL SEA in buffer, and from 10 pg/mL to 10 ng/mL SEA in spiked milk samples. The detection limits of the developed immunoassays performed in milk were: 48 pg/mL with polyclonal antibody and 9 pg/mL with monoclonal antibody.

Conclusion:

A rapid and sensitive fluorescence immunoassay based on magnetic nanoparticles with a polyclonal and monoclonal antibody for determination of staphylococcal enterotoxin A in milk was developed.

The fetal fibronectin test: 25 years after its development, what is the evidence regarding its clinical utility? A systematic review and meta-analysis

Background: The identification of women at risk for preterm birth should allow interventions which could improve neonatal outcome. Fetal fibronectin, a glycoprotein which acts normally as glue between decidua and amniotic membranes could be a good marker of impending labour when its concentration in cervicovaginal secretions between 22 and 36 weeks of gestation is ≥50 ng/mL. Many authors worldwide have tested this marker with many different methodologies and clinical settings, but conclusions about its clinical use are mixed. It is time for a comprehensive update through a systematic review and meta-analysis.Methods: We searched PubMed, Cochrane Library, and Embase, supplemented by manual search of bibliographies of known primary and review articles, international conference papers, and contact with experts from 1-1990 to 2-2018. We have selected all type of studies involving fetal fibronectin test accuracy for preterm delivery. Two authors independently extracted data about study characteristics and quality from identified publications. Contingency tables were constructed. Reference standards were preterm delivery before 37, 36, 35, 34, and 32 weeks, within 28, 21, 14, or 7 d and within 48 h. Data were pooled to produce summary likelihood ratios for positive and negative tests results.Results: One hundred and ninety-three primary studies were identified allowing analysis of 53 subgroups. In all settings, none of the summary likelihood ratios were >10 or <0.1, thus indicating moderate prediction, particularly in asymptomatic women and in multiple gestations.Conclusions: The fetal fibronectin test should not be used as a screening test for asymptomatic women. For high-risk asymptomatic women, and especially for women with multiple pregnancies, the performance of the fetal fibronectin test was also too low to be clinically relevant. Consensual use as a diagnostic tool for women with suspected preterm labor, the best use policy probably still depends on local contingencies, future cost-effectiveness analysis, and comparison with other more recent available biochemical markers.