Nanopore Discrimination of Coagulation Biomarker Derivatives and Characterization of a Post-Translational Modification

Characterizing Prion-Like Protein Aggregation: Emerging Nanopore-Based Approaches

Prion-like protein aggregation is characteristic of numerous neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. This process involves the formation of aggregates ranging from small and potentially neurotoxic oligomers to highly structured self-propagating amyloid fibrils. Various approaches are used to study protein aggregation, but they do not always provide continuous information on the polymorphic, transient, and heterogeneous species formed. This review provides an updated state-of-the-art approach to the detection and characterization of a wide range of protein aggregates using nanopore technology. For each type of nanopore, biological, solid-state polymer, and nanopipette, discuss the main achievements for the detection of protein aggregates as well as the significant contributions to the understanding of protein aggregation and diagnostics.

Identification of Conformational Variants for Bradykinin Biomarker Peptides from a Biofluid Using a Nanopore and Machine Learning

There is a current need to develop methods for the sensitive detection of peptide biomarkers in complex mixtures of molecules, such as biofluids, to enable early disease detection. Moreover, to our knowledge, there is currently no detection method capable of identifying the different conformations of a peptide biomarker differing by a single amino acid. Single-molecule nanopore sensing promises to provide this level of resolution. In order to be able to identify these differences in a biofluid such as serum, it is necessary to carefully characterize electrical parameters to obtain specific signatures of each biomarker population observed. We are interested here in a family of peptide biomarkers, kinins such as bradykinin and des-Arg9 bradykinin, that are involved in many disabling pathologies (allergy, asthma, angioedema, sepsis, or cancer). We show the proof of concept for direct identification of these biomarkers in serum at the single-molecule level using a protein nanopore. Each peptide exhibits two unique electrical signatures attributed to specific conformations in bulk. The same signatures are found in serum, allowing their discrimination and identification in a complex mixture such as biofluid. To extend the utility of our experimental results, we developed a principal component analysis approach to define the most relevant electrical parameters for their identification. Finally, we used semisupervised classification to assign each event type to a specific biomarker at physiological serum concentration. In the future, single-molecule scale analysis of peptide biomarkers using a powerful nanopore coupled with machine learning will facilitate the identification and quantification of other clinically relevant biomarkers from biofluids.

Bone Cement Implantation Syndrome: A Rare Disaster Following Cemented Hip Arthroplasties-Clinical Considerations Supported by Case Studies

Severe symptoms such as hypoxemia, hypotension, and unexpected loss of consciousness may develop during surgical interventions that use polymethyl methacrylate (PMMA), or as it is commonly known, bone cement. Physicians recognize this amalgam of clinical manifestations more and more as a distinct entity that bears the name of bone cement implantation syndrome (BCIS). Trauma cases, especially hip fractures, are seen to have a higher incidence of developing this complication compared to orthopedic elective ones. This research aims to present a detailed description of six severe BCIS cases in order to raise awareness and to emphasize its importance. Five of them had fatal outcomes, which demonstrate the necessity of future research on this topic, as little is known about it presently. In the Discussion section, a narrative overview from the scientific literature is performed on potential risk factors, prevention measures, and management strategies. The experience gathered through this case series may aid medical staff in the development of diagnostic and therapeutic protocols, thus improving safety when cemented surgical techniques are used on a high-risk group of patients.