Edgar Goluch

Northeastern University, Chemical Engineering, Faculty Member

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entrepreneur academic developing technologies that changes paradigms
Supervisors: Serge Lemay and Chang Liu
Phone: +1-617-373-3500
Address: Department of Chemical Engineering
Northeastern University
360 Huntington Ave., 342SN
Boston, MA 02115
U. S. A.

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Papers by Edgar Goluch

Electrochemical Monitoring of Pseudomonas Aeruginosa Biofilms in Microfluidic Channels

Polydimethylsiloxane microfluidic channels were irreversibly plasma bonded to microfabricated ele... more Polydimethylsiloxane microfluidic channels were irreversibly plasma bonded to microfabricated electrochemical sensors to monitor the presence of Pseudomonas aeruginosa biofilms. Channels were electrochemically monitored via square wave voltammetry to detect the presence of redox molecules produced by wild type strain PA14 biofilms growing inside the channels.

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Real-Time Evaluation of Effectiveness of Antimicrobial Coatings with Surface Plasmon Resonance Imaging

In this study, Surface Plasmon Resonance imaging (SPRi) was used to evaluate the effectiveness of... more In this study, Surface Plasmon Resonance imaging (SPRi) was used to evaluate the effectiveness of antimicrobial coatings for preventing initial bacterial attachment and subsequent biofilm formation. SPRi is capable of monitoring of biological interactions in real time on a large (1 cm) sensor surface. Here, we monitored the growth and biofilm formation of Pseudomonas aeruginosa (CFP PA01) on gold, bovine serum albumin (BSA), casein, and antibiotic surfaces. Patterning of multiple coatings on a single sensor surface and simultaneous exposure to flowing solution containing bacteria allowed a direct, quantitative comparison of the effectiveness of the coatings.

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Electrophoresis on a polyester thread coupled with an end‐channel pencil electrode detector

ELECTROPHORESIS

We present the design and characterization of a low cost, thread‐based electrophoretic device wit... more We present the design and characterization of a low cost, thread‐based electrophoretic device with integrated electrochemical detection. The device has an end‐channel pencil graphite electrode placement system for performing electrochemical detection on the thread electrophoresis platform with direct sample pipetting onto the thread. We also established the use of methylene blue and neutral red as a pair of reference migration markers for separation techniques coupled with electrochemical detection, as they have different colors for visual analysis and are both electroactive. Importantly, neutral red was also found to migrate at a similar rate to the EOF, indicating that it can be used as a visual identifier of EOF. The utility of our system was demonstrated by electrophoretic separation and electrochemical detection of physiologically relevant concentrations of pyocyanin in a solution containing multiple electroactive compounds. Pyocyanin is a biomarker for the detection of pathogenic Pseudomonas aeruginosa and has a redox potential that is similar to that of methylene blue. The system was able to effectively resolve methylene blue, neutral red, and pyocyanin in less than 7 min of electrophoretic separation. The theoretical limit of detection for pyocyanin was determined to be 559 nM. The electrophoretic mobilities of methylene blue (0.0236 ± 0.0007 mm2/V·s), neutral red (0.0149 ± 0.0007 mm2/V·s), and pyocyanin (0.0107 ± 0.0003 mm2/V·s) were also determined.

Bacterial chatter in chronic wound infections

Wound Repair and Regeneration

One of the hallmark characteristics of chronic diabetic wounds is the presence of biofilm‐forming... more One of the hallmark characteristics of chronic diabetic wounds is the presence of biofilm‐forming bacteria. Bacteria encapsulated in a biofilm may coexist as a polymicrobial community and communicate with each other through a phenomenon termed quorum sensing (QS). Here, we describe the QS circuits of bacterial species commonly found in chronic diabetic wounds. QS relies on diffusion of signaling molecules and the local concentration changes of these molecules that bacteria experience in wounds. These biochemical signaling pathways play a role not only in biofilm formation and virulence but also in wound healing. They are, therefore, key to understanding the distinctive nature of these infections. While several in vivo and in vitro models exist to study QS in wounds, there has been limited progress in understanding the interplay between QS molecules and host factors that contribute to wound healing. Lastly, we examine the potential of targeting QS for both diagnosis and therapeutic intervention purposes.

Treating Polymicrobial Infections in Chronic Diabetic Wounds

Clinical Microbiology Reviews

SUMMARY This review provides a comprehensive summary of issues associated with treating polyclona... more SUMMARY This review provides a comprehensive summary of issues associated with treating polyclonal bacterial biofilms in chronic diabetic wounds. We use this as a foundation and discuss the alternatives to conventional antibiotics and the emerging need for suitable drug delivery systems. In recent years, extraordinary advances have been made in the field of nanoparticle synthesis and packaging. However, these systems have not been incorporated into the clinic for treatments other than for cancer or severe genetic diseases. We present a unifying perspective on how the field is evolving and the need for an early amalgamation of engineering principles and a biological understanding of underlying phenomena in order to develop a therapy that is translatable to the clinic in a shorter time.

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Quantification of colloidal filtration of polystyrene micro-particles on glass substrate using a microfluidic device

Colloids and surfaces. B, Biointerfaces, 2018

A microfluidic device was designed to investigate filtration of particles in an electrolyte in th... more A microfluidic device was designed to investigate filtration of particles in an electrolyte in the presence of liquid flow. Polystyrene spheres in potassium chloride solution at concentrations of 3-100 mM were allowed to settle and adhere to a glass substrate. A particle free solution at the same concentration was then flushed through the microfluidic channel at 0.03-4.0 mL/h. As the hydrodynamic drag on the adhered particles exceeded the intersurface interaction with the substrate, "pull-off" occurred and the particles detached. Filtration efficiency, α, was shown to a function of both ionic concentration of the liquid medium and flow speed, consistent with a phenomenological model based on the classical DLVO theory. The results elucidates the underlying physics of filtration.

Electrochemical Detection of Signaling Biomolecules In Nanofluidic Devices

The sensitive and selective detection of signaling biomolecules is an important component of medi... more The sensitive and selective detection of signaling biomolecules is an important component of medical research, with applications ranging from developmental biology to degenerative diseases. Several neurotransmitters, such as serotonin, dopamine, and norephinephrine, are redox active catecholamines that can be electrically detected. However, electrochemical detection of biological samples is limited since interfering species, such as ascorbic acid, mask the signal of the target molecules. We have developed a nanofluidic device that ...

Electrochemical detection of Pseudomonas in wound exudate samples from patients with chronic wounds

Wound Repair and Regeneration, 2016

In clinical practice, point-of-care diagnostic testing has progressed rapidly in the last decade.... more In clinical practice, point-of-care diagnostic testing has progressed rapidly in the last decade. For the field of wound care, there is a compelling need to develop rapid alternatives for bacterial identification in the clinical setting, where it generally takes over 24 hours to receive a positive identification. Even new molecular and biochemical identification methods require an initial incubation period of several hours to obtain a sufficient number of cells prior to performing the analysis. Here we report the use of an inexpensive, disposable electrochemical sensor to detect pyocyanin, a unique, redox-active quorum sensing molecule released by Pseudomonas aeruginosa, in wound fluid from patients with chronic wounds enrolled in the WE-HEAL Study. By measuring the metabolite excreted by the cells, this electrochemical detection strategy eliminates sample preparation, takes less than a minute to complete, and requires only 7.5 microliters of sample to complete the analysis. The electrochemical results were compared against 16S rRNA profiling using 454 pyrosequencing. Blind identification yielded 9 correct matches, 2 false negatives, and 3 false positives giving a sensitivity of 71% and specificity of 57% for detection of Pseudomonas. Ongoing enhancement and development of this approach with a view to develop a rapid point-of-care diagnostic tool is planned. This article is protected by copyright. All rights reserved.

Optimization of a Microfluidic Chip for the Biobarcode Assay

ABSTRACT We demonstrate in this work the successful application of functionalized gold nanopartic... more ABSTRACT We demonstrate in this work the successful application of functionalized gold nanoparticles and magnetic microparticles in the development of an integrated lab-on-achip-system. By employing the BioBarCode Assay, we have shown that it is possible to quantitatively identify ultra-low concentrations of proteins not only in buffer solutions, but also in serum samples using a microfluidic device. Furthermore, we have developed a method using microarrayed DNA patterns inside the microfluidic channels that will make ...

Electrochemical Detection of Enzyme Kinetics Using Nanofluidic Devices

Amperometric detection is an attractive detection scheme for mico-and nanofluidic systems as it d... more Amperometric detection is an attractive detection scheme for mico-and nanofluidic systems as it directly yields an electrical signal. However, this scheme is not often utilized because of its limited sensitivity. We overcome this limitation by employing a nanofluidic device consisting of a solution-filled cavity bounded by two closely spaced parallel electrodes that can amplify the current by repeatedly reducing and oxidizing electroactive species. Here we demonstrate the utility of such a device to measure enzyme kinetics in real time. We compare the conversion of p-cresol into methylquinone by tyrosinase using our nanofluidic device against a standard UV-Vis spectroscopic protocol.

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Microfluidic Systems and Components

Microfluidic systems and components. A microfluidic system includes one or more functional units ... more Microfluidic systems and components. A microfluidic system includes one or more functional units or microfluidic chips, configured to perform constituent steps in a process and interconnected to form the system. A multi-layer microfluidic system includes a separate dedicated fluid layer and dedicated electromechanical layer connected via through-holes. Electromechanical components are formed on the electromechanical layer.

Electrochemically monitoring the antibiotic susceptibility of Pseudomonas aeruginosa biofilms

The Analyst, 2015

We demonstrate a simple microfluidic system for screening antibiotic efficacy and determining min... more

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Electrochemical nanofluidics: The mesoscopic limit

We have developed a lithography-based nanofluidic device for sensitive electrochemical detection ... more We have developed a lithography-based nanofluidic device for sensitive electrochemical detection applications. The device consists of a solution-filled channel bounded by parallel electrodes that are separated by ~50 nm. Redox cycling at the two electrodes is used to amplify the electrochemical signals from molecules in the volume between the electrodes, and can lead to dramatic improvements in sensitivity and/or selectivity. Interestingly, an important limit to sensitivity is placed by statistical fluctuations in the number of molecules present in the device, a consequence of its extremely small volume (a few femtolitres). In this Proceedings article, we focus on the consequences of these statistical fluctuations on the signal-to-noise ratio of electrochemical sensors based on redox cycling.

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A Microfluidic Chip for Bio-Bar-Code-Based Detection of Proteins

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Improved monitoring of P. aeruginosa on agar plates

Stock pyocyanin at 5 mg/mL in dimethyl sulfoxide was diluted in TSB, TSB agar, and Kings A agar t... more Stock pyocyanin at 5 mg/mL in dimethyl sulfoxide was diluted in TSB, TSB agar, and Kings A agar to concentrations from 0 to 100 μM. TSB samples were scanned using square wave voltammetry (SWV) on three separate disposable carbon electrodes three times each from-0.5 to 0.0 V at a frequency and amplitude voltage of 15 Hz and 50 mV, respectively. Agar samples were scanned three times on a single electrode at the same parameters The peak current values after baseline subtraction were averaged and are reported in Fig. S1. A linear fit over the range of pyocyanin concentrations was obtained, yielding a slope of 1.8x10-1 , 1.7x10-1 , and 1.3x10-1 A/M for pyocyanin in TSB, TSB agar, and King's A agar, respectively. The King's A agar fit was used to calculate the concentration of pyocyanin diffusing through the King's A agar during experiments.

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Real-Time Detection of Bacterial Biofilm Growth Using Surface Plasmon Resonance Imaging

Surface Plasmon Resonance imaging (SPRi) was used for real-time detection of bacterial growth ins... more Surface Plasmon Resonance imaging (SPRi) was used for real-time detection of bacterial growth inside microfluidic channels. First, 50 micron diameter beads were spotted on a gold coated prism surface and visualized with both SPRi and a stereo microscope to validate images. Then, fluorescent Escherichia coli was loaded into microfluidic polydimethylsiloxane (PDMS) channels on the SPRi sensor surface and observed for 6 hours. Afterwards, the sample was imaged with a fluorescence microscope. Both images showed bacterial growth at the same locations in the channels, confirming that bacterial growth can be directly monitored in real-time by SPRi.

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Investigating Enzyme Kinetics Using Nanofluidic Devices

We have developed a nanofluidic device consisting of two parallel electrodes in a nanometer-scale... more We have developed a nanofluidic device consisting of two parallel electrodes in a nanometer-scale cavity with openings at both ends. Electrochemically active molecules that enter the cavity transfer charge between the electrodes when a potential difference is applied. Typically, electrochemical reactions only involve one or a few electrons per molecule, rendering direct detection of a single molecule in solution virtually impossible. This limitation is overcome, in this situation, by redox cycling, where each molecule can transfer, on average, thousands of electrons by repeatedly traveling between the electrodes before escaping back out into the bulk. Further, the devices are created using standard microfabrication technology, and can therefore be produced reliably in large quantities. Numerous sensing applications can be envisioned with such nanofluidic devices, ranging from water purity to drug screening. This talk will focus on employing these devices for determining enzyme kinet...

SPRi-based adenovirus detection using a surrogate antibody method

by Nimet Yildirim and Edgar Goluch

Biosensors and Bioelectronics, 2015

Adenovirus infection, which is a waterborne viral disease, is one of the most prevelant causes of... more Adenovirus infection, which is a waterborne viral disease, is one of the most prevelant causes of human morbidity in the world. Thus, methods for rapid detection of this infectious virus in the environment are urgently needed for public health protection. In this study, we developed a rapid, real-time, sensitive, and label-free SPRi-based biosensor for rapid, sensitive and highly selective detection of adenoviruses. The sensing protocol consists of mixing the sample containing adenovirus with a predetermined concentration of adenovirus antibody. The mixture was filtered to remove the free antibodies from the sample. A secondary antibody, which was specific to the adenovirus antibody, was immobilized onto the SPRi chip surface covalently and the filtrate was flowed over the sensor surface. When the free adenovirus antibodies bound to the surface-immobilized secondary antibodies, we observed this binding via changes in reflectivity. In this approach, a higher amount of adenoviruses resulted in fewer free adenovirus antibodies and thus smaller reflectivity changes. A dose-response curve was generated, and the linear detection range was determined to be from 10PFU/mL to 5000PFU/mL with an R(2) value greater than 0.9. The results also showed that the developed biosensing system had a high specificity towards adenovirus (less than 20% signal change when tested in a sample matrix containing rotavirus and lentivirus).

A modular microfluidic architecture for integrated biochemical analysis

by Annelise Barron, Jwa-Min Nam, and Edgar Goluch

Proceedings of the …, Jan 1, 2005

Microfluidic laboratory-on-a-chip (LOC) systems based on a modular architecture are presented. Th... more Microfluidic laboratory-on-a-chip (LOC) systems based on a modular architecture are presented. The architecture is conceptualized on two levels: a single-chip level and a multiple-chip module (MCM) system level. At the individual chip level, a multilayer approach segregates components belonging to two fundamental categories: passive fluidic components (channels and reaction chambers) and active electromechanical control structures (sensors and actuators). This distinction is explicitly made to simplify the development process and minimize cost. Components belonging to these two categories are built separately on different physical layers and can communicate fluidically via cross-layer interconnects. The chip that hosts the electromechanical control structures is called the microfluidic breadboard (FBB). A single LOC module is constructed by attaching a chip comprised of a custom arrangement of fluid routing channels and reactors (passive chip) to the FBB. Many different LOC functions can be achieved by using different passive chips on an FBB with a standard resource configuration. Multiple modules can be interconnected to form a larger LOC system (MCM level). We demonstrated the utility of this architecture by developing systems for two separate biochemical applications: one for detection of protein markers of cancer and another for detection of metal ions. In the first case, free prostate-specific antigen was detected at 500 aM concentration by using a nanoparticle-based bio-bar-code protocol on a parallel MCM system. In the second case, we used a DNAzyme-based biosensor to identify the presence of Pb 2؉ (lead) at a sensitivity of 500 nM in <1 nl of solution.

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Electrochemical Study of Enzyme Kinetics in Nanofluidic Thin Layer Cell

In this talk, we describe the method for immobilization of tyrosinase in the nanochannel where tw... more In this talk, we describe the method for immobilization of tyrosinase in the nanochannel where two planar microelectrodes (~ 5-10 µm) separated by a thin layer of fluid (~ 50 nm) are fabricated on a chip using optical lithography (Figure 1). We present our recent studies on electrochemical studies of the tyrosinase kinetics which converts electrochemically inactive monophenols into active diphenols and quinones in the nanochannel. The Michaelis-Menten model is used to describe kinetic behavior of the enzyme.

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