A Multiplexed Microfluidic Platform for Bone Marker Measurement: A Proof-of-Concept

PoCOsteo: generic novel platform for bone turnover marker measurement & monitoring

Despite the increasing efforts in improving bone health assessments, current diagnostics suffer from critical shortcomings. The present article therefore describes a multiplex label-free immunosensor designed and validated for the assessment of two bone turnover markers (BTMs), namely beta isomerized C-terminal telopeptide of type I collagen (CTx) and Procollagen I Intact N-Terminal (PINP), the combination of which is needed to illustrate an accurate overview of bone health. The immunosensor was then tested outside and inside of a microsystem, with the aim of becoming compatible with a point of care system fabricated for automated assessment of these biomarkers later-on at patient side. Custom-made monoclonal antibodies were specifically designed for this purpose in order to guarantee the selectivity of the immunosensor. In the final platform, a finger prick blood sample is introduced into the microfluidic manifolds without any need for sample preparation step, making the tool suitable for near patient and outside of the central laboratory applications. The platform was exploited in 30 real blood samples with the results validated using electrochemiluminescence immunoassay. The results revealed the platform was capable of measuring the target analyte with high sensitivity and beyond the recommended clinical reference range for each biomarker (CTx: 104-1028 ng L-1 and PINP: 16-96 μg L-1, correspondingly). They also showed the platform to have a limit of detection of 15 (ng L-1) and 0.66 (μg L-1), a limit of quantification of 49 (ng L-1) and 2.21 (μg L-1), and an inter- and intra-assay coefficient of variance of 5.39-6.97% and 6.81-5.37%, for CTx and PINP respectively, which is comparable with the gold standard. The main advantage of the platform over the state-of-the art was the capability of providing the results for two markers recommended for assessing bone health within 15 minutes and without the need for skilled personnel or costly infrastructure.

Recent Microfluidic Innovations for Sperm Sorting

Sperm selection is a clinical need for guided fertilization in men with low-quality semen. In this regard, microfluidics can provide an enabling platform for the precise manipulation and separation of high-quality sperm cells through applying various stimuli, including chemical agents, mechanical forces, and thermal gradients. In addition, microfluidic platforms can help to guide sperms and oocytes for controlled in vitro fertilization or sperm sorting using both passive and active methods. Herein, we present a detailed review of the use of various microfluidic methods for sorting and categorizing sperms for different applications. The advantages and disadvantages of each method are further discussed and future perspectives in the field are given.

Aptamer selection and aptasensor construction for bone density biomarkers

Osteoporosis (OP) is a bone disease involved in dysregulation of one of the bone metabolism arms, formation, or desorption cause a porous bone. Osteocalcin (OC) and beta-crosslap (BC), are the well-known markers for OP, which are connected to bone formation and desorption, respectively. In addition to the OP biomarker, BC is also used as an estrogen replacement therapeutic monitoring. ELISA and other antibody-based detection methods are routinely used for measuring OC and BC. These methods have limitations that include thermostability, sensitivity, sacrificing animals, and cost of production. However, aptamer-based-assays are of interest to overcome these drawbacks and achieve the most specific and robust application. Herein, specific aptamers for OC and BC were selected by the systematic evolution of ligands by exponential enrichment (SELEX) method from the pool of ssDNA library with 60 random sequences. The binding affinity (K_d) of the selected aptamers were evaluated against the respective biomarkers. The high-affinity aptamers of OC and BC showed the K_d values of 59 and 55 nM respectively. A graphene oxide-based aptasensors were fabricated from the high-affinity aptamers, and the detection limits of OC and BC were found to be 0.4 pg/ml and 0.21 pg/ml, respectively. These aptasensors have been tested with OC and BC spiked buffer samples and validated using serum samples collected from osteoporotic rats.

Protocol for a multicentre, prospective cohort study of clinical, proteomic and genomic patterns associated with osteoporosis to develop a multidimensional fracture assessment tool: the PoCOsteo Study

INTRODUCTION

The HORIZON 2020 project PoCOsteo aims (1) to develop a multidimensional fracture risk assessment tool which would take into account all factors known to be related to an individual's fracture risk. The fracture risk model is intended to be developed in two different populations, namely a European and a Middle Eastern one; (2) to develop a medical device, which would measure and/or quantify proteomic as well as genomic factors as present in whole blood samples collected through finger prick; (3) to test the clinical applicability and the validity of prototypes of the to be developed point of care device at both clinical centres.

METHODS AND ANALYSIS

This article presents the protocol of this prospective cohort that will be carried out independently at two different centres (Division of Endocrinology and Diabetology at the Medical University of Graz (MUG) as a clinic-based cohort, and Endocrinology and Metabolism Research Institute (EMRI) at the Tehran University of Medical Sciences (TUMS) as a population-based cohort). The final aim is to develop a fracture risk assessment model, which would include clinical risk factors, biochemical markers of bone turnover, as well as specific genomic factors. The derivation cohorts will consist of individuals aged 50 years and above. The period of observation for each patient will be 12 months; an extension phase, which would last for another 2 years, is also planned.

ETHICS AND DISSEMINATION

These studies are conducted in accordance with the World Medical Association Declaration of Helsinki. The Iranian part was approved by the Research Ethics Committee of EMRI, TUMS. The Austrian part was approved by the Ethics Committee of the Medical University of Graz. Based on the gathered information, a multidimensional fracture assessment tool will be designed which will later be added to the PoCOsteo device.

Numerical simulation of a multi-inlet microfluidic device for biosensing purposes in osteoporosis management

Objectives

In this paper, the effect of the position of the inlet and outlet microchannels on the flow profile and the geometry of the recognition chamber for sample pre-treatment in an electrochemical biosensor to be used in osteoporosis management were investigated.

Methods

All numerical computation presented in this work were performed using COMSOL Multiphysics and Fluent. Simulation was performed for a three-dimensional, incompressible Navier-Stokes flow and so explicit biphasic volume of fluid (VOF) equations were used.

Results

In the designed microfluidic system, a pressure-driven laminar flow with no-slip boundary condition was responsible for fluid actuation through microchannels in a reproducible approach. Based on the simulation results, the number of outlets was increased and the angel through which the inlets and outlets were attached to the microchamber was changed so that the dead volume would be eliminated and the fluid flow trajectory, the velocity field and pressure were evenly distributed across the chamber. The Re number in the inlets was equal to 4.41, suggesting a laminar flow at this site.

Conclusion

The simulation results along with the fact that the design change was tested using laser ablated tape and a color dye at different steps provided the researchers with the opportunity to study the changes in a fast and accurate but cheap method. The absence of backflow helps with the cross-talk concern in the channels and the lack of bubbles and complete coverage of the chamber helps with a better surface modification and thus better sensing performance.

Paper-based microfluidic device for diagnosis of osteoporosis markers

Background: Development of cost-effective platforms for identification of biomarkers is of paramount importance in low-income settings. The present work focuses on the development of a microfluidic paper-based analytical device (μPADs) for the diagnosis of osteoporosis by measuring three important bone biomarkers – calcium, alkaline phosphatase and vitamin D. Methods: Antibody-based detection is realized in μPAD reservoirs based on principle of colorimetric sensing, where μPAD images are captured using a smartphone. The results are compared with the calibration curves to give proper quantification of analytes. Conclusion: This device can be potentially developed into a point-of-care diagnostic device for low-income settings. To the best of our understanding, a μPAD platform for simultaneous diagnosis of multiple osteoporosis markers is not reported yet.

Development of Porous Coatings Enriched with Magnesium and Zinc Obtained by DC Plasma Electrolytic Oxidation

Coatings with developed surface stereometry, being based on a porous system, may be obtained by plasma electrolytic oxidation, PEO (micro arc oxidation, MAO). In this paper, we present novel porous coatings, which may be used, e.g., in micromachine’s biocompatible sensors’ housing, obtained in electrolytes containing magnesium nitrate hexahydrate Mg(NO₃)₂·6H₂O and/or zinc nitrate hexahydrate Zn(NO₃)₂·6H₂O in concentrated phosphoric acid H₃PO₄ (85% w/w). Complementary techniques are used for coatings’ surface characterization, such as scanning electron microscopy (SEM), for surface imaging as well as for chemical semi-quantitative analysis via energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES), and X-ray powder diffraction (XRD). The results have shown that increasing contents of salts (here, 250 g/L Mg(NO₃)₂·6H₂O and 250 g/L Zn(NO₃)₂·6H₂O) in electrolyte result in increasing of Mg/P and Zn/P ratios, as well as coating thickness. It was also found that by increasing the PEO voltage, the Zn/P and Mg/P ratios increase as well. In addition, the analysis of XPS spectra revealed the existence in 10 nm top of coating magnesium (Mg²⁺), zinc (Zn²⁺), titanium (Ti⁴⁺), and phosphorus compounds (PO₄³⁻, or HPO₄²⁻, or H₂PO₄⁻, or P₂O₇⁴⁻).

Multidisciplinary Role of Microfluidics for Biomedical and Diagnostic Applications: Biomedical Microfluidic Devices

Life scientists are closely working with engineers to solve biological and biomedical problems through the application of engineering tools.[...].