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Lipomas are benign subcutaneous tumors arising from adipocytes. Although they are the most common tumors found in the body, their presentation in the head and neck region is relatively infrequent. Further, the most common site of presentation in the neck is the posterior part. Here we are presenting a case of a giant lipoma occupying both anterior and posterior triangles of the neck, lying deep to the sternocleidomastoid muscle with retrosternal extension. [ABSTRACT FROM AUTHOR]

The present work deals with the development of a non-invasive optical glucose biosensor using saliva samples and a smartphone. The sensor was fabricated with a simple methodology by immobilization of Glucose oxidase enzyme along with a pH responsive dye on a filter paper based strip. The strip changes color upon reaction with glucose present in saliva and the color changes were detected using a smartphone camera through RGB profiling. This standalone biosensor showed good sensitivity and low interference while operating within 20 s response time. We used various means for improvements such as the use of slope method instead of differential response; use of a responsive pH indicator and made numerous tweaks in the smartphone app. Calibration with spiked saliva samples with slopes for (R + G + B) pixels revealed an exponentially increasing calibration curve with a linear detection range of 50–540 mg/dL, sensitivity of 0.0012 pixels sec −1 /mg dL −1 and LOD of 24.6 mg/dL. The biosensor was clinically validated on both healthy and diabetic subjects divided into several categories based on sex, age, diabetic status etc. and correlation between blood and salivary glucose has been established for better standardization of the sensor. Correlation of 0.44 was obtained between blood and salivary glucose in healthy individuals whereas it was 0.64 and 0.94 in case of prediabetic and diabetic patients respectively. The developed biosensor has the potential to be used for mass diagnosis of diabetes especially in such areas where people remain prohibited from routine analysis due to high healthcare cost. Apart from that, a smartphone would be the only device the user needs for this measurement, along with a disposable low cost test strip. [ABSTRACT FROM AUTHOR]

In our present study, we developed an optical biosensor for direct determination of salivary glucose by using immobilized glucose oxidase enzyme on filter paper strip (specific activity 1.4 U/strip) and then reacting it with synthetic glucose samples in presence of co-immobilized color pH indicator. The filter paper changed color based on concentration of glucose in reaction media and hence, by scanning this color change (using RGB profiling) through an office scanner and open source image processing software (GIMP) the concentration of glucose in the reaction medium could be deduced. Once the biosensor was standardized, the synthetic glucose sample was replaced with human saliva from donors. The individual's blood glucose level at the time of obtaining saliva was also measured using an Accuchek ™ active glucometer (Roche Inc.). In this preliminary study, a correlation of nearly 0.64 was found between glucose levels in saliva and blood of healthy individuals and in diabetic patients it was nearly in the order of 0.95, thereby validating the importance of salivary analysis. The RGB profiling method obtained a detection range of 9–1350 mg/dL glucose at a response time of 45 s and LOD of 22.2 mg/dL. [ABSTRACT FROM AUTHOR]

Abstract: We report simple and rapid capillary electrophoresis (CE) separation followed by in-channel pulsed amperometric detection (PAD) of three common triazine herbicides: simazine, atrazine and ametryn that are used to control broad leaf weeds and annual grasses. For their detection in soil and groundwater samples, a CE–PAD microfluidic chip was fabricated using standard photolithography methods. Cyclic voltammetry was conducted on these herbicides that exhibited a characteristic cathodic peak at −0.70V for simazine or atrazine and −0.80V for ametryn, without any anodic peak at reverse scan, indicating that the cathodic peaks were irreversible electron transfer processes. For effective CE–PAD separation of triazine complex, the capillary was filled with 1.5% agarose. The pulsed amperometric detection of these chemicals ensured better sensor response and low electrode fouling. The average electropherogram of simazine, atrazine and ametryn showed single peaks at 58, 66 and 74s, respectively at 20V/cm separation potential. A mixture of all three herbicides showed similar separated peaks. HPLC was also conducted in a soil spiked with these pollutants to compare the method. The results hold the promise of detecting triazines within a very short time. [Copyright &y& Elsevier]

Abstract: A DNA hybridization sensor using pentacene thin film transistors (TFTs) is an excellent candidate for disposable sensor applications due to their low-cost fabrication process and fast detection. We fabricated pentacene TFTs on glass substrate for the sensing of DNA hybridization. The ss-DNA (polyA/polyT) or ds-DNA (polyA/polyT hybrid) were immobilized directly on the surface of the pentacene, producing a dramatic change in the electrical properties of the devices. The electrical characteristics of devices were studied as a function of DNA immobilization, single-stranded vs. double-stranded DNA, DNA length and concentration. The TFT device was further tested for detection of λ-phage genomic DNA using probe hybridization. Based on these results, we propose that a “label-free” detection technique for DNA hybridization is possible through direct measurement of electrical properties of DNA-immobilized pentacene TFTs. [ABSTRACT FROM AUTHOR]

Abstract: The lyophilized biomass of bacterium Brevibacterium ammoniagenes was immobilized in polystyrene sulphonate–polyaniline (PSS–PANI) conducting polymer on a Pt twin wire electrode by potentiostatic electropolymerization. The bacterial cells retained their viability as well as urease activity under entrapped state, as confirmed with bacterial live–dead fluorescent assay and enzymatic assays. The entrapped cells were visualized using scanning electron microscope. The immobilized cells were used as a source of unpurified urease to develop a conductometric urea biosensor. The catalytic action of urease in the sensor released ammonia, thereby causing an increase in the pH of the microenvironment. The pH dependant change in the resistivity of the polymer was used as the basis of sensing mechanism. The sensor response was linear over a range of 0–75mM urea with a sensitivity of 0.125mM−1. The sensor could be reused for 12–15 independent measurements and was quite stable in dry as well as buffered storage condition at 4°C for at least 7 days. [Copyright &y& Elsevier]

Abstract: A urea biosensor was developed using the urease entrapped in polyvinyl alcohol (PVA) and polyacrylamide (PAA) composite polymer membrane. The membrane was prepared on the cheesecloth support by gamma-irradiation induced free radical polymerization. The performance of the biosensor was monitored using a flow-through cell, where the membrane was kept in conjugation with the ammonia selective electrode and urea was added as substrate in phosphate buffer medium. The ammonia produced as a result of enzymatic reaction was monitored potentiometrically. The potential of the system was amplified using an electronic circuit incorporating operational amplifiers. Automated data acquisition was carried by connecting the output to a 12-bit analog to digital converter card. The sensor working range was 1–1000 mM urea with a response time of 120 s. The enzyme membranes could be reused 8 times with more than 90% accuracy. The biosensor was tested for blood urea nitrogen (BUN) estimation in clinical serum samples. The biosensor showed good correlation with commercial Infinity™ BUN reagent method using a clinical chemistry autoanalyzer. The membranes could be preserved in phosphate buffer containing dithiothreitol, β-mercaptoethanol and glycerol for a period of two months without significant loss of enzyme activity. [Copyright &y& Elsevier]

Abstract: An optical microbial biosensor was described for the detection of methyl parathion pesticide. Whole cells of Flavobacterium sp. were immobilized by trapping in glass fiber filter and were used as biocomponent along with optic fiber system. Flavobacterium sp. has the organophosphorus hydrolase enzyme, which hydrolyzes the methyl parathion into detectable product p-nitrophenol. The immobilized microbial biocomponent was disposable, cost-effective and showed high reproducibility and uniformity. The detection of methyl parathion by the use of disposable microbial biocomponent with optical biosensor was simple, single step and direct measurement of very low quantity of the sample. The home made reaction vessel was small and needed only 75μl of sample. A lower detection limit 0.3μM methyl parathion was estimated from the linear range (4–80μM) of calibration plot of organophosphorus hydrolase enzymatic assay. The applicability to synthetic methyl parathion spiked samples was demonstrated. [Copyright &y& Elsevier]

Abstract: Composite polymer membrane of polyvinyl alcohol (PVA) and acrylamide was prepared on cheesecloth support by γ-irradiation induced free radical polymerization. The enzyme urease was entrapped in the membrane during polymerization and was cross-linked within the matrix using glutaraldehyde. The membranes could be reused a number of times without significant loss of urease activity. [Copyright &y& Elsevier]

The article presents a case study of a 58-year-old man with cough recurring for seven months. It says that histopathological findings show indications of a benign tracheal adenoma. It mentions various treatment methods performed such as an elective low tracheotomy and endobronchial LASER excision of the tumor mass. It discusses tracheal tumors by which many patients are undiagnosed due to diverse clinical presentation such as asymptomatic cases, hemoptysis or malignancies.

In the present study, we have developed a smartphone based handheld optical biosensor for determination of urea in saliva. A simple strategy was adopted by immobilization of urease enzyme along with a pH indicator on a filter paper based strip. The strip changed color upon the reaction with urea present in saliva and the color change can be estimated using our smartphone based application based on RGB profiling. Calibration of the biosensor was carried out using spiked saliva samples and an exponentially decreasing calibration curve has been obtained for green pixel intensity in the broad range (10–1000 mgdL −1 ) with a linear detection range of 10–260 mgdL −1 and a response time of 20 s. The sensitivity reported for the biosensor in the clinically significant range was −0.005 average pixels sec −1 /mgdL −1 with a LOD of 10.4 mgdL −1 . Studies carried out on spiked saliva samples showed a good correlation between salivary urea estimated using our biosensor against phenol-hypochlorite based spectroscopic procedure. Development of a smartphone based biosensor for urea estimation eliminates the need for procuring a dedicated instrument as well as trained technician for daily monitoring and saves time as compared to traditional laboratory methods of analysis. [ABSTRACT FROM AUTHOR]

Abstract: A low-cost miniaturized flow-through device was fabricated using conventional photolithographic technique for lysis of whole cells using electrochemically generated hydroxyl groups. The device used low impedance Au-interdigitated electrode (IDE) fabricated on glass substrate to input DC potential to the overlaid PDMS based microchannel. The lysis of human cell line MCF-10A could be achieved between 2 and 5V of DC input with optimum release of genomic DNA at 5V for 5min, which is the lowest potential range reported in any such study. The lysate was extracted to confirm release of genomic DNA and was successfully tested for PCR grade purity of DNA by amplifying a known tumor suppressor gene SMAD4. The proposed method was non-destructive for biocomponents due to absence of Joule heating and shall find use in miniaturized PCR analysis as well as where native protein extraction is required under aseptic conditions. [Copyright &y& Elsevier]

Abstract: Capillary electrophoresis amperometric detection (CE–AD) microchip was fabricated for separation and detection of DNA fragments. The chip was fabricated on glass substrate and microchannels were laid in PDMS mold. The capillary was filled with 5% polyacrylamide gel and separation of DNA fragments of different molecular weight was achieved by application of 100V DC potential across sample and waste reservoirs made at the capillary ends. The amperometric detection (AD) system involved in-channel gold microelectrodes to analyze oxidation peak for adenine residues in DNA chain. This technique was used in resolving single as well as double stranded DNA fragments. [Copyright &y& Elsevier]

A dopamine biosensor has been developed using nickel oxide nanoparticles (NPs) and tyrosinase enzyme conjugate. Nickel oxide (NiO) NPs were synthesized by sol–gel method using anionic surfactant, sodium dodecyl sulphate (SDS), as template to control the size of synthesized nanoparticles. The structural and morphological studies of the prepared NPs were carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. Afterwards, tyrosinase enzyme molecules were adsorbed on NiO NPs surface and enzyme coated NPs were deposited on indium tin oxide (ITO) coated flexible polyethylene terephthalate (PET) substrate by solution casting method. The formation of enzyme–NPs conjugate was investigated by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) techniques and used in selective detection and estimation of neurochemical dopamine by electrochemical method. The fabricated Tyrosinase/NiO/ITO electrode exhibits high sensitivity of 60.2 nA/µM in linear detection range (2–100 μM) with a detection limit of 1.038 μM. The proposed sensor had a response time of 45 s, long shelf life (45 days) with good reproducibility and selectivity in presence of interfering substances and was validated with real samples. The tyrosinase enzyme functionalized NiO platform has good bio-sensing efficacy and can be used in detection of other catecholamines and phenolic neurochemicals. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) is the most toxic mycotoxin, naturally occurring in food items, and it causes several types of lethal diseases. Therefore, a rapid and convenient detection method for AFB1 is the first step toward overcoming the effect of AFB1. The current work presents the development of an efficient microfluidic electrochemical-based biosensor using tri-manganese tetroxide nanoparticles (Mn3O4 nps) for AFB1 detection. The Mn3O4 nps were synthesized at room temperature through the co-precipitation route. Its phase purity, structural and morphological studies have been characterized through x-ray diffraction, Raman spectroscopy, energy-dispersive x-ray, Fourier transform infrared spectroscopy and transmission electron microscopy. The mask-less UV-lithography was carried out to fabricate the three-electrode chip and microfluidic channel of the microfluidic electrochemical biosensing system. The designed microfluidic immunosensor (BSA/Ab-AFB1/Mn3O4/ITO) was fabricated using the three-electrode chip, microfluidic channel in poly-dimethyl siloxane. The fabricated sensor exhibited the 3.4 ÎĽ A ml ngâˆ'1 cmâˆ'2 sensitivity and had the lowest lower detection limit of 0.295 pg mlâˆ'1 with the detection range of 1 pg mlâˆ'1 to 300 ng mlâˆ'1. Additionally, the spiked study was also performed with this immunoelectrode and a recovery rate was obtained of 108.2%. [ABSTRACT FROM AUTHOR]

Abstract: Eggshell membrane is a natural material, essentially made up of protein fibers having flexibility in the aqueous solution and possessing gas and water permeability. It is used as a biomembrane for immobilization of urease for the development of a potentiometric urea biosensor. Eggshell membrane was treated with polyethyleneimine (PEI) to impart polycation characteristics. Urease was immobilized on the PEI treated eggshell membrane through adsorption. SEM study was carried out to observe the changes in surface morphology after immobilization. FTIR study of membrane was carried out to observe the changes in IR spectra after immobilization of enzyme. Immobilized membrane was associated with ammonium ion selective electrode. Biosensor exhibited sigmoidal responses for the urea concentration range from 0.5 to 10mM. The response time of the biosensor was 120s. A single membrane was reused for 270 reactions without loss of activity. The urease–eggshell membranes were stable for 2months when stored in buffer even at room temperature. [Copyright &y& Elsevier]

Abstract: A capillary electrophoresis amperometric detector was fabricated using Prussian blue (PB) modified indium tin oxide (ITO) electrode and twisted microchannel configuration. These devices were used for detection of endocrine disruptors, such as bisphenol A (BPA) and butylphenol after their effective separation in microchannel. The microchip had a limit of detection (LOD) as low as 59nM for analytes. This approach was further applied in detection of these contaminants in Styrofoam food container used in many East Asian countries, such as Korea and China, for packaging of instant noodle, a popular fast food. [Copyright &y& Elsevier]

• Ranibizumab is sold under trade name Lucentis and is used for treating macular degeneration and is very expensive drug, though it is produced in bioreactor. • Reason being no process analytical technique available for its online/inline monitoring for yield optimization. • We are for the first time generated aptamers for this analyte and developed an impedimetric sensor for its detection. • The aptamer was generated using modified SELEX process with good specificity (Kd in nM range) and selectivity. • A microfluidic chip was designed with immobilized aptamer for impedimetric label free detection of Ranibizumab in inline mode from a bioreactor. • The device showed low LOD, excellent selectivity and specificity for Ranibizumab without the need of sample pretreatment and preconcentration. • The detection time was just 30 min compared to several hours needed with HPLC based method. • Our sensing technique shall also be helpful to similar PAT control of bioproduction if aptamers/affinity agent for those analytes are generated/known. We have developed an aptamer based microfluidic chip for inline monitoring of Ranibizumab in bioreactors. Aptamers for Ranibizumab were generated using 10 rounds of the SELEX process. Two of the aptamers exhibited high affinity towards the target analyte with a dissociation constant within 20–30 nM range. The one with best affinity towards analyte was immobilized on gold micro-electrodes on a microfluidic chip, which was fabricated with glass base and PDMS top using conventional photolithographic technique. Immobilization steps were characterized using FTIR and EIS. Non-faradaic EIS measurement was used for label-free detection of Ranibizumab. The linear range of detection and LOD were found to be 25−100 nM and 25 nM respectively, which was significantly better than HPLC based detection method (about 240 nM). Further, this microchip-based detection did not require sample preconcentration or preprocessing and as a result, the detection time was reduced to 30 min compared to several hours with HPLC. The proposed detection system was validated using real samples of culture broths and no interferences were observed. Statistical analysis confirmed the correlation between the microfluidic chip and HPLC based method. As the selected aptamer was found highly specific for Ranibizumab, it can also be used for purification of Ranibizumab in affinity columns. Therefore, commercialization of this aptamer and microfluidic chip could have a significant impact on purification, various steps during biopharmaceutical production (clone selection and process optimization) and inline detection of Ranibizumab. [ABSTRACT FROM AUTHOR]

A nanostructured composite film comprising reduced graphene oxide (rGO) and nickel oxide (NiO) nanoparticles (NPs) has been prepared and utilized for development of a simple yet efficient sensor for detection of dopamine and epinephrine in a single run. The hybrid material rGO-NiO nanocomposite was synthesized chemically, and the formation of nanocomposite was confirmed via X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, UV-Vis, and Fourier transform infrared (FTIR) spectroscopic techniques. The incorporation of NiO NPs on rGO support was found to provide improved sensing characteristics at electrode interface due to enhanced electron mobility on rGO sheet and high catalytic activity of NiO NPs. Subsequently, the synthesized rGO-NiO nanocomposite was deposited onto indium tin oxide (ITO)-coated glass substrate by simple drop-casting method, and the electrode was characterized through atomic force microscopy (AFM) and scanning electron microscopic (SEM) studies. After optimization of experimental conditions electrochemically for its high sensitivity, the fabricated rGO-NiO/ITO electrode was used for simultaneous detection of dopamine and epinephrine by square wave voltammetry (SWV) method. The results showed high sensitivity of 0.545 and 0.638 μA/μM for dopamine and epinephrine respectively in a broad linear range of 0.5-50 μM. Moreover, remarkable detection limits of 0.495 and 0.423 μM were found for dopamine and epinephrine, and the developed sensor exhibited a wide separation of 380 mV between the respective detection peaks of dopamine and epinephrine. Beside this, the proposed sensor was successfully applied in presence of high concentration of interfering agents, ascorbic acid and uric acid, and validated with real serum samples. [ABSTRACT FROM AUTHOR]