Biomedical Engineering

Nowadays most of the blood pressure measuring devices rely on a common concept of inflatable cuff to the arm which is based on auscultatory or oscillometry principle. These existing blood pressure meters, based on cuff are considered to be inconvenient for daily monitoring and these are very sensitive to artefacts due to the presence of cuff. The other non invasive methods like PTT, PAT require more no. of parameters in order to estimate the blood pressure. This paper is aimed at designing a non invasive cuff-less cardiovascular parameters estimation system from Photoplethysmography(PPG) Signals technique Using LabVIEW and analysis using MATLAB. A ppg signal is voltage derived signal generated by the photo detector from light with the changes in the blood volume. It does reflect the movement of blood in the blood vessel, going in a wave like motion from the heart to the fingertips through the blood vessels. It has been considered as non-invasive, reliable, simple, and cost-effective method for measuring arterial pulse waves in relation to changes in wave amplitude. This study aimed to investigate the possibilities of monitoring the pressure system status by using morphological features of PPG components. The specific characteristic feature of the PPG wave such as Pulse height and Pulse width has been taken into count for the Blood Pressure estimation. The estimation is further done using a mathematical tool such as regression analysis via MATLAB.

Point-of-care (POC) diagnostic devices have been predicted to provide a boon in health care especially in the diagnosis and detection of diseases. POC devices have been found to have many advantages like a rapid and precise response, portability, low cost, and non-requirement of specialized equipment. The major objective of a POC diagnostic research is to develop a chip-based, self-containing miniaturized device that can be used to examine different analytes in complex samples. Further, the integration of microfluidics (MF) with advanced biosensor technologies is likely to result in improved POC diagnostics. This paper presents the overview of the different materials (glass, silicon, polymer, paper) and techniques for the fabrication of MF based POC devices along with their wide range of biosensor applications. Besides this, the authors have presented in brief the challenges that MF is currently facing along with possible solutions that may result in the availability of the accessib...

We report results of the studies relating to the development of a non-invasive, label free immunosensor based on nanostructured hafnium oxide (hafinia) deposited onto indium tin oxide (ITO) coated glass for oral cancer biomarker (CYFRA-21-1) detection in human saliva. The nanostructured hafnia (nHfO 2) has been synthesized via one step low temperature hydrothermal process and modified with 3-aminopropyltriethoxy silane (APTES) for covalent immobilization of monoclonal antibodies (anti-CYFRA-21-1). Bovine serum albumin (BSA) was used to block non-specific sites at the anti-CYFRA-21-1/APTES/nHfO 2 /ITO electrode surface. The structural, morphological and spectroscopic characterization of the synthesized nanomaterials and fabricated electrodes has been carried out using Xray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) studies, respectively. The results of response studies conducted on BSA/anti-CYFRA-21-1/APTES/nHfO 2 /ITO immunoelectrode reveal that this biosensor has high sensitivity (9.28 A mL ng −1 cm −2), wide linear detection range (2-18 ng mL −1) and fast response time (15 min). This immunosensor has been validated with enzyme linked immunosorbent assay (ELISA) in saliva samples of oral cancer patients.

W e report results of the studies relating to the fabrication of nanostructured zirconia (ZrO 2) based immunosensor for cardiac troponin I biomarker (myocardial infarction) detection. One step, low temperature hydrothermal process has been used for the synthesis of nanostructured ZrO 2 (4.5 nm). These ZrO 2 nanoparticles have been functionalized with 3-amino propyl triethoxy silane (APTES) and thereafter electrophoretically deposited (15 V, 3 minutes) on indium tin oxide coated glass electrode (ITO). EDC/NHS chemistry has been used for covalent immobilization of anti-troponin-I (anti-cTnI) onto APTES/ZrO 2 /ITO electrode. Structural, morphological and functional characterization of the synthesized nanoparticles and the fabricated immunoelectrode have been carried out via X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry techniques. The results of electrochemical response studies of BSA/anti-cTnI/APTES/ZrO 2 /ITO immunoelectrode reveal that this smart platform can be used for the detection of troponin I biomarker with a wide linear detection range (0.01 to 100 ng mL-1), high sensitivity (3.7×10-4 mA mL ng-1 cm-2), remarkable lower detection limit (0.036 ng mL-1) and stability of upto 30 days. The obtained results have been validated through enzyme linked immunosorbent assay (ELISA).

We report results of the studies relating to fabrication of nanostructured metal oxide (NMO) based cancer biosensor. With the help of 2D electroactive reduced graphene oxide (RGO), we successfully inhibited the Brownian motion of NMO that led to reduced agglomeration of NMO. The nanostructured hafnium oxide (nHfO2) was used as a model NMO. The reduced agglomeration of nHfO2 was achieved through controlled hydrothermal synthesis and investigated via nanoparticles tracking analysis (NTA). X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM) techniques were used for phase identification as well as morphological analysis of the synthesized nanohybrid (nHfO2@RGO) material. The 3-aminopropyl triethoxysilane (APTES) was used for the functionalization of nHfO2@RGO and electrophoretic deposition (EPD) technique was used for its deposition onto ITO coated glass electrode. Further, antibodies of cancer biomarker (anti-CYFRA-21-1) were immobiliz...

We report results of the studies relating to the fabrication of a label-free, flexible, light weight and disposable conducting paper based immunosensing platform comprising of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and nanostructured iron oxide (nFe 2 O 3 @PEDOT:PSS) nanocomposite for detection of carcinoembryonic antigen (CEA), a cancer biomarker. The effect of various solvents such as sorbitol, ethanol, propanol, n-methyl-2pyrrolidone (NMP) and dimethyl sulfoxide (DMSO) on the electrical conductivity of Whatman filter paper (WP) modified with nFe 2 O 3 @PEDOT:PSS/WP was investigated. The electrical conductivity of the PEDOT:PSS/WP electrode was found to be enhanced by two orders of magnitude (from 6.8 x 10-4 to 1.92 x 10-2 Scm-1) after its treatment with DMSO. Further, nFe 2 O 3 doped PEDOT:PSS/WP electrode exhibited the electrical conductivity as 2.4 x 10-2 Scm-1. Besides this, the incorporation of iron oxide nanoparticles (nFe 2 O 3) into PEDOT:PSS/WP resulted in improved electrochemical performance and signal stability. This nFe 2 O 3 @PEDOT:PSS/WP based platform was used for immobilization of the anticarcinoembronic antigen (anti-CEA) protein for quantitative estimation of cancer biomarker (CEA). The results of electrochemical response studies revealed that this conducting paper based immunoelectrode had a sensitivity of 10.2 µAng-1 mLcm-2 in the physiological range (4-25 ngmL-1) and shelf life of 34 days. Further, the proposed immunoelectrode was validated with conventional ELISA for the detection of CEA in serum samples of cancer patients.

We report results of the studies relating to the development of an efficient biosensor for non-invasive detection of CYFRA-21-1 cancer biomarker. We used a low dielectric constant material (nanostructured yttrium oxide, nY2O3) for the fabrication of the biosensing platform. The nY2O3 was synthesized via solvothermal process and functionalized using 3-aminopropyl triethoxy silane (APTES). Electrophoretic deposition (EPD) of the functionalized nanomaterial (APTES/nY2O3) onto an indium tin oxide (ITO)-coated glass electrode was conducted at a DC potential of 50V for 60s. The EDC-NHS chemistry was used for covalent immobilization of −COOH bearing monoclonal anti-CYFRA-21-1 onto −NH2 groups of APTES/nY2O3/ITO electrode. To avoid the non-specific interaction on the anti-CYFRA-21-1/APTES/nY2O3/ITO immunoelectrode, bovine serum albumin (BSA) was used. X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FESEM) were utilized for st...

Serum samples of breast cancer patients The serum samples of breast cancer patients were obtained from the Rajiv Gandhi Cancer Institute and Research Centre, Rohini, Delhi, (India). All the serum samples were collected under the protocol approved by the Rajiv Gandhi Cancer Institute and Research Centre Institutional Review board (RGCRIC/IRB/12/2016). Prior to collecting the serum samples, the written informed consents were taken from all the patients We performed double antibody sandwich ELISA in anti-HER-2 coated 96 micro titter wells plate. The standard and real samples were run in triplicate followed by the colorimetric reaction recorded at 450 nm by ELISA plate reader (iMARK, Bio-rad, USA).

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Molecular diagnostics has been the front runner in the world’s response to the COVID-19 pandemic. Particularly, reverse transcriptase-polymerase chain reaction (RT-PCR) and the quantitative variant (qRT-PCR) have been the gold standard for COVID-19 diagnosis. However, faster antigen tests and other point-of-care (POC) devices have also played a significant role in containing the spread of SARS-CoV-2 by facilitating mass screening and delivering results in less time. Thus, despite the higher sensitivity and specificity of the RT-PCR assays, the impact of POC tests cannot be ignored. As a consequence, there has been an increased interest in the development of miniaturized, high-throughput, and automated PCR systems, many of which can be used at point-of-care. This review summarizes the recent advances in the development of miniaturized PCR systems with an emphasis on COVID-19 detection. The distinct features of digital PCR and electrochemical PCR are detailed along with the challenges...

Rapid and simple electroanalysis of acrylamide (ACR) was feasible by a gold electrode modified with gold nanoparticles (AuNPs) and dithiothreitol (DTT) with enhanced detection sensitivity and selectivity. The roughness of bare gold (Au) increased from 0.03 μm to 0.04 μm when it was decorated with AuNPs. The self-assembly between DTT and AuNPs resulted in a surface roughness of 0.09 μm. The DTT oxidation occurred at +0.92 V. The Au/AuNPs/DTT surface exhibited a surface roughness of 0.24 μm after its exposure to ACR with repeated analysis. SEM imaging illustrated the formation of a polymer layer on the Au/AuNPs/DTT surface. Surface plasmon resonance analysis confirmed the presence of AuNPs and DTT on the gold electrode and the binding of ACR to the electrode’s active surface area. The peak area obtained by differential pulse voltammetry was inversely proportional to the ACR concentrations. The limit of detection (LOD) and the limit of quantitation (LOQ) were estimated to be 3.11 × 10−...

Local blood pressure measurements provide important information on the state of health of organs in the body and can be used to diagnose diseases in the heart, lungs, and kidneys. This paper presents an experimental setup for investigating the ambient pressure sensitivity of a contrast agent using diagnostic ultrasound. The setup resembles a realistic clinical setup utilizing a single array transducer for transmit and receive. The ambient pressure sensitivity of SonoVue (Bracco, Milano, Italy) was measured twice using two different acoustic driving pressures, which were selected based on a preliminary experiment. To compensate for variations in bubble response and to make the estimates more robust, the relation between the energy of the subharmonic and the fundamental component was chosen as a measure over the subharmonic peak amplitude. The preliminary study revealed the growth stage of the subharmonic component to occur at acoustic driving pressures between 300 and 500 kPa. Based on this, the pressure sensitivity was investigated using a driving pressure of 485 and 500 kPa. At 485 kPa, a linear pressure sensitivity of 0.42 dB/kPa was found having a linear correlation coefficient of 0.94. The second measurement series at 485 kPa showed a sensitivity of 0.41 dB/kPa with a correlation coefficient of 0.89. Based on the measurements at 500 kPa, this acoustic driving pressure was concluded to be too high causing the bubbles to be destroyed. The pressure sensitivity for these two measurement series were 0.42 and 0.25 dB/kPa with linear correlation coefficients of 0.98 and 0.93, respectively.