A DNA-based nano-immunoassay for the label-free detection of glial fibrillary acidic protein in multicell lysates

Second Cancer Affecting the Central Nervous System: Systematic Literature Review Exploring the Link Between Malignant Melanoma and Glioblastoma

BACKGROUND

Glioblastoma (GBM) is a malignant primary brain cancer, among the most devastating and lethal diseases of the central nervous system. Similarly, malignant melanoma (MM) is responsible for most skin cancer-related deaths. A link between those 2 aggressive cancers has not yet been established. We present here a systematic review of the literature and an exemplificative case.

METHODS

A systematic review of the literature was conducted to assess possible commonalities between MM and GBM. An exemplificative surgical vignette of a 73-year-old patient with the occurrence of a frontobasal GBM after surgical removal of a metastasis of MM in the same location was then detailed.

RESULTS

Fifteen studies published in the English international literature support a link between MM and GBM, both based on epidemiologic and pathophysiologic/genetic aspects. This theory is reinforced by our surgical vignette of a collision tumor with the occurrence of both tumors in the same location several years apart.

CONCLUSIONS

The evidence reported in the literature, as well as our surgical vignette, support a likely link between the pathogenesis of GBM and MM.

Atomic Force Microscopy Application for the Measurement of Infliximab Concentration in Healthy Donors and Pediatric Patients with Inflammatory Bowel Disease

The use of infliximab has completely changed the therapeutic landscape in inflammatory bowel disease. However, despite its proven efficacy to induce and maintain clinical remission, increasing evidence suggests that treatment failure may be associated with inadequate drug blood concentrations. The introduction of biosensors based on different nanostructured materials for the rapid quantification of drugs has been proposed for therapeutic drug monitoring. This study aimed to apply atomic force microscopy (AFM)-based nanoassay for the measurement of infliximab concentration in serum samples of healthy donors and pediatric IBD patients. This assay measured the height signal variation of a nanostructured gold surface covered with a self-assembled monolayer of alkanethiols. Inside this monolayer, we embedded the DNA conjugated with a tumor necrosis factor able to recognize the drug. The system was initially fine-tuned by testing known infliximab concentrations (0, 20, 30, 40, and 50 nM) in buffer and then spiking the same concentrations of infliximab into the sera of healthy donors, followed by testing pediatric IBD patients. A good correlation between height variation and drug concentration was found in the buffer in both healthy donors and pediatric IBD patients (p-value < 0.05), demonstrating the promising use of AFM nanoassay in TDM.

Pushing the boundaries of accuracy and reliability during stereotactic procedures: A prospective study on 526 biopsies comparing the frameless robotic and Image-Guided Surgery systems

INTRODUCTION

A 12-year long, prospective, single center study was conducted, comparing two frameless systems for brain biopsies: ROSA robotic-assisted stereotaxy and BrainLab Varioguide image-guided stereotaxy (Image Guided Surgery, IGS).

METHOD

All consecutive adult and pediatric patients undergoing frameless brain biopsies were included. Successfully achieving diagnosis was the primary endpoint, analysis of all periprocedural complications was the secondary endpoint, and the tertiary endpoint was the length of the procedure, with the aim of assessing of the learning curve for each operator over time. The results for the ROSA robot and the Varioguide system were compared and benchmarked to data from the literature.

RESULTS

We performed 526 on 516 patients, 314 with the ROSA robot (Group A) and 212 with the IGS Varioguide (Group B). Histological diagnosis was achieved in 97.4% of cases in Group A, versus 93.3% in Group B (p < 0.05). No statistically significant difference was found for secondary and tertiary endpoints. The complication rate appeared similar between the 2 frameless systems, with a hemorrhagic complications rate of 3.5% in Group A and 4.7% in Group B. Permanent neurological deterioration was only recorded in 0.8% of cases from Group B. Mortality was recorded in 0.3% in Group A and 0.4% in Group B.

CONCLUSION

This study provides evidence to confirm that robotic surgery lives up to its promises of increased safety, accuracy, and reliability.

Computational Evolution of Beta-2-Microglobulin Binding Peptides for Nanopatterned Surface Sensors

The bottom-up design of smart nanodevices largely depends on the accuracy by which each of the inherent nanometric components can be functionally designed with predictive methods. Here, we present a rationally designed, self-assembled nanochip capable of capturing a target protein by means of pre-selected binding sites. The sensing elements comprise computationally evolved peptides, designed to target an arbitrarily selected binding site on the surface of beta-2-Microglobulin (β2m), a globular protein that lacks well-defined pockets. The nanopatterned surface was generated by an atomic force microscopy (AFM)-based, tip force-driven nanolithography technique termed nanografting to construct laterally confined self-assembled nanopatches of single stranded (ss)DNA. These were subsequently associated with an ssDNA-peptide conjugate by means of DNA-directed immobilization, therefore allowing control of the peptide's spatial orientation. We characterized the sensitivity of such peptide-containing systems against β2m in solution by means of AFM-based differential topographic imaging and surface plasmon resonance (SPR) spectroscopy. Our results show that the confined peptides are capable of specifically capturing β2m from the surface-liquid interface with micromolar affinity, hence providing a viable proof-of-concept for our approach to peptide design.

HSV-Encephalitis Reactivation after Cervical Spine Surgery

Background

Herpes simplex virus encephalitis (HSVE) is a viral neurological disorder that occurs when the herpes simplex virus (HSV) enters the brain. The disorder is characterized by the inflammation of the brain and a significant decline in mental status. HSVE reactivation after neurosurgery, although rare, can cause severe neurological deterioration. The high morbidity rate among untreated patients necessitates prompt diagnosis and management.

Case Description

We report a case of a 78-year-old woman with no known prior history of HSVE and declining mental status eleven days after a posterior C3-T1 decompression and instrumented fusion following resection of an intradural extramedullary tumor, confirmed to be meningioma on final pathology. Reactivation of HSV-1 encephalitis was suspected to be the underlying cause of her symptoms, though MRI scans of the brain for HSVE were negative. The patient reacted positively to a 21-day treatment of acyclovir and was discharged with a neurological status comparable to her preoperative baseline. This case contributes to the literature in that it is the first reported instance of HSVE reactivation after intradural cervical spinal surgery with negative MRI findings.

Conclusion

We recommend utilizing multiple tests, including PCR, EEG, and MRI, for postoperative neurosurgery patients that have decreased mental status in order to quickly and correctly diagnose/treat patients who are HSVE positive. Clinicians should consider the possibility of receiving false-negative results from PCR, CSF, EEG, or MRI tests before terminating treatment for HSVE reactivation.

Biopsying a spinal cord lesion: A diagnostic dilemma. Case report and review of literature

Spinal cord biopsy is a difficult procedure fraught with the risk of false-negative results or even misdiagnosis in up to 30% of cases. Differential diagnoses of spinal cord lesions include a wide range of inflammatory, infectious and neoplastic diseases. Given the importance of correctly managing these pathologies, it is crucial to avoid delays in making the correct diagnosis in order to improve the patient's outcome. We present here the case of a 21-year-old male with rapidly progressing sphincter and lower limb motor dysfunctions up to complete paraplegia with evidence of thoracic spinal cord lesion on magnetic resonance imaging. None of the blood and cerebrospinal fluid tests pointed to a diagnosis, while a first spinal cord biopsy revealed an inflammatory necrotic process. After several weeks of empirical treatments and clinical stability, the patient started having focal structural seizures that became generalized with local progression of the lesion and diffuse leptomeningeal spread on magnetic resonance imaging. A second spinal cord biopsy found a grade IV glioblastoma with H3 K27M histone mutation. Unfortunately the patient passed away before any treatment could be initiated. In this report, the authors analyze the difficulty of making the rapid, correct diagnosis of a highly malignant intrinsic spinal cord lesion, discussing also possible strategies to avoid diagnostic delays and to improve the outcome of these difficult patients.

How Nanotechnology and Biomedical Engineering Are Supporting the Identification of Predictive Biomarkers in Neuro-Oncology

The field of neuro-oncology is rapidly progressing and internalizing many of the recent discoveries coming from research conducted in basic science laboratories worldwide. This systematic review aims to summarize the impact of nanotechnology and biomedical engineering in defining clinically meaningful predictive biomarkers with a potential application in the management of patients with brain tumors. Data were collected through a review of the existing English literature performed on Scopus, MEDLINE, MEDLINE in Process, EMBASE, and/or Cochrane Central Register of Controlled Trials: all available basic science and clinical papers relevant to address the above-stated research question were included and analyzed in this study. Based on the results of this systematic review we can conclude that: (1) the advances in nanotechnology and bioengineering are supporting tremendous efforts in optimizing the methods for genomic, epigenomic and proteomic profiling; (2) a successful translational approach is attempting to identify a growing number of biomarkers, some of which appear to be promising candidates in many areas of neuro-oncology; (3) the designing of Randomized Controlled Trials will be warranted to better define the prognostic value of those biomarkers and biosignatures.

Understanding the Pathological Basis of Neurological Diseases Through Diagnostic Platforms Based on Innovations in Biomedical Engineering: New Concepts and Theranostics Perspectives

The pace of advancement of genomics and proteomics together with the recent understanding of the molecular basis behind rare diseases could lead in the near future to significant advances in the diagnosing and treating of many pathological conditions. Innovative diagnostic platforms based on biomedical engineering (microdialysis and proteomics, biochip analysis, non-invasive impedance spectroscopy, etc.) are introduced at a rapid speed in clinical practice: this article primarily aims to highlight how such platforms will advance our understanding of the pathological basis of neurological diseases. An overview of the clinical challenges and regulatory hurdles facing the introduction of such platforms in clinical practice, as well as their potential impact on patient management, will complement the discussion on foreseeable theranostic perspectives. Indeed, the techniques outlined in this article are revolutionizing how we (1) identify biomarkers that better define the diagnostic criteria of any given disease, (2) develop research models, and (3) exploit the externalities coming from innovative pharmacological protocols (i.e., those based on monoclonal antibodies, nanodrugs, etc.) meant to tackle the molecular cascade so far identified.

Computational design of cyclic peptides for the customized oriented immobilization of globular proteins

The oriented immobilization of proteins, key for the development of novel responsive biomaterials, relies on the availability of effective probes. These are generally provided by standard approaches based on in vivo maturation and in vitro selection of antibodies and/or aptamers. These techniques can suffer technical problems when a non-immunogenic epitope needs to be targeted. Here we propose a strategy to circumvent this issue by in silico design. In our method molecular binders, in the form of cyclic peptides, are computationally evolved by stochastically exploring their sequence and structure space to identify high-affinity peptides for a chosen epitope of a target globular protein: here a solvent-exposed site of β2-microglobulin (β2m). Designed sequences were screened by explicit solvent molecular dynamics simulations (MD) followed by experimental validation. Five candidates gave dose-response surface plasmon resonance signals with dissociation constants in the micromolar range. One of them was further analyzed by means of isothermal titration calorimetry, nuclear magnetic resonance, and 250 ns of MD. Atomic-force microscopy imaging showed that this peptide is able to immobilize β2m on a gold surface. In short, we have shown by a variety of experimental techniques that it is possible to capture a protein through an epitope of choice by computational design.

Current and Future Applications of Biomedical Engineering for Proteomic Profiling: Predictive Biomarkers in Neuro-Traumatology

This systematic review aims to summarize the impact of nanotechnology and biomedical engineering in defining clinically meaningful predictive biomarkers in patients with traumatic brain injury (TBI), a critical worldwide health problem with an estimated 10 billion people affected annually worldwide. Data were collected through a review of the existing English literature performed on Scopus, MEDLINE, MEDLINE in Process, EMBASE, and/or Cochrane Central Register of Controlled Trials. Only experimental articles revolving around the management of TBI, in which the role of new devices based on innovative discoveries coming from the field of nanotechnology and biomedical engineering were highlighted, have been included and analyzed in this study. Based on theresults gathered from this research on innovative methods for genomics, epigenomics, and proteomics, their future application in this field seems promising. Despite the outstanding technical challenges of identifying reliable biosignatures for TBI and the mixed nature of studies herein described (single cells proteomics, biofilms, sensors, etc.), the clinical implementation of those discoveries will allow us to gain confidence in the use of advanced neuromonitoring modalities with a potential dramatic improvement in the management of those patients.

Quantification of Circulating Cancer Biomarkers via Sensitive Topographic Measurements on Single Binder Nanoarrays

Early detection of cancer plays a crucial role in disease prognosis. It requires the recognition and quantification of low amounts of specific molecular biomarkers, either free or transported inside nanovesicles, through the development of novel sensitive diagnostic technologies. In this context, we have developed a nanoarray platform for the noninvasive quantification of cancer biomarkers circulating in the bloodstream. The assay is based on molecular manipulation to create functional spots of surface-immobilized binders and differential topography measurements. It is label-free and requires just a single binder per antigen, and when it is implemented with fluorescence labeling/readout, it can be used for epitope mapping. As a benchmark, we focused on the plasma release of Her2 extracellular domain (ECD), a proposed biomarker for the progression of Her2-positive tumors and response to anticancer therapies. By employing robust, easily engineered camelid nanobodies as binders, we measured ECD-Her2 concentrations in the range of the actual clinical cutoff value for Her2-positive breast cancer. The specificity for Her2 detection was preserved when it was measured in parallel with other potential biomarkers, demonstrating a forthcoming implementation of this approach for multiplexing analysis. Prospectively, this nanorarray platform may be customized to allow for the detection of promising new classes of circulating biomarkers, such as exosomes and microvesicles.

Mismatch detection in DNA monolayers by atomic force microscopy and electrochemical impedance spectroscopy

Background: DNA hybridization is at the basis of most current technologies for genotyping and sequencing, due to the unique properties of DNA base-pairing that guarantee a high grade of selectivity. Nonetheless the presence of single base mismatches or not perfectly matched sequences can affect the response of the devices and the major challenge is, nowadays, to distinguish a mismatch of a single base and, at the same time, unequivocally differentiate devices read-out of fully and partially matching sequences.

Results: We present here two platforms based on different sensing strategies, to detect mismatched and/or perfectly matched complementary DNA strands hybridization into ssDNA oligonucleotide monolayers. The first platform exploits atomic force microscopy-based nanolithography to create ssDNA nano-arrays on gold surfaces. AFM topography measurements then monitor the variation of height of the nanostructures upon biorecognition and then follow annealing at different temperatures. This strategy allowed us to clearly detect the presence of mismatches. The second strategy exploits the change in capacitance at the interface between an ssDNA-functionalized gold electrode and the solution due to the hybridization process in a miniaturized electrochemical cell. Through electrochemical impedance spectroscopy measurements on extended ssDNA self-assembled monolayers we followed in real-time the variation of capacitance, being able to distinguish, through the difference in hybridization kinetics, not only the presence of single, double or triple mismatches in the complementary sequence, but also the position of the mismatched base pair with respect to the electrode surface.

Conclusion: We demonstrate here two platforms based on different sensing strategies as sensitive and selective tools to discriminate mismatches. Our assays are ready for parallelization and can be used in the detection and quantification of single nucleotide mismatches in microRNAs or in genomic DNA.

Nanosensors for early cancer detection and for therapeutic drug monitoring

The use of nanotechnology for drug delivery in cancer therapy has raised high expectations. Additionally, the use of nanomaterials in sensors to extract and detect tumor specific biomarkers, circulating tumor cells, or extracellular vesicles shed by the tumor holds the promise to detect cancer much earlier and hence improve long-term survival of the patients. Moreover, the monitoring of the anticancer drug concentration, which has a narrow therapeutic window, will allow for a personalized dosing of the drug and will lead to improved therapeutic outcome and life quality of the patient. This review will provide an overview on the use of nanosensors for the early diagnosis of cancer and for the therapeutic drug monitoring, giving some examples. We envision nanosensors to make significant improvements in the cancer management as easy-to-use point-of-care devices for a broad population of users.