Designing a nano-interface in a microfluidic chip to probe living cells: challenges and perspectives

Microfluidic technology for cell biology-related applications: a review

Fluid flow at the microscale level exhibits a unique phenomenon that can be explored to fabricate microfluidic devices integrated with components that can perform various biological functions. In this manuscript, the importance of physics for microscale fluid dynamics using microfluidic devices has been reviewed. Microfluidic devices provide new opportunities with regard to spatial and temporal control over cell growth. Furthermore, the manuscript presents an overview of cellular stimuli observed by combining surfaces that mimic the complex biochemistries and different geometries of the extracellular matrix, with microfluidic channels regulating the transport of fluids, soluble factors, etc. We have also explained the concept of mechanotransduction, which defines the relation between mechanical force and biological response. Furthermore, the manipulation of cellular microenvironments by the use of microfluidic systems has been highlighted as a useful device for basic cell biology research activities. Finally, the article focuses on highly integrated microfluidic platforms that exhibit immense potential for biomedical and pharmaceutical research as robust and portable point-of-care diagnostic devices for the assessment of clinical samples.

Tango of dual nanoparticles: Interplays between exosomes and nanomedicine

Exosomes are lipid bilayer vesicles released from cells as a mechanism of intracellular communication. Containing information molecules of their parental cells and inclining to fuse with targeted cells, exosomes are valuable in disease diagnosis and drug delivery. The realization of their clinic applications still faces difficulties, such as lacking technologies for fast purification and functional reading. The advancement of nanotechnology in recent decades makes it promising to overcome these difficulties. In this article, we summarized recent progress in utilizing the physiochemical properties of nanoparticles (NPs) to enhance exosome purification and detection sensitivity or to derive novel technologies. We also discussed the valuable applications of exosomes in NPs‐based drug delivery. Till now most studies in these fields are still at the laboratory research stage. Translation of these bench works into clinic applications still has a long way to go.

Microbial cell factories a new dimension in bio-nanotechnology: exploring the robustness of nature

Bio-based nanotechnology has its existence in biological dimensions e.g. microbial cell factories (bacteria, fungi. algae, yeast, cyanobacteria) plants, and biopolymers. They provide multipurpose biological platforms to supply well-designed materials for diverse nano-biotechnological applications. The "green or bio-based synthesis of nanoparticles (NPs)" has witnessed a research outburst in the past decade. The bio-based synthesis of NPs using microbial cell factories is a benign process and requires mild conditions for the synthesis with end products being less/non-toxic. As a result, its application has extended in multitudinous industries including environment, cosmetics, and pharmaceutical. Thus, the present review summarizes all the significant aspects of nanotechnology and the reason to switch towards the bio-based synthesis of NPs using microbial cell factories. It consists of a detailed description of the bio-based methods employed for the synthesis and classification of NPs. Also, a comprehensive study on the application of bio-based NPs in the various industrial and biotechnological domains has been discussed. The limitation and its solution would help identify the applicability of NPs to "identified and unidentified" sectors.

Controllable design of a nano-bio aptasensing interface based on tetrahedral framework nucleic acids in an integrated microfluidic platform

The limited reaction time and sample volume in the confined space of microfluidic devices give considerable importance to the development of more effective biosensing interfaces. Herein, the self-assembling of tetrahedral framework nucleic acids (FNAs) with controllable size on the interface of the microfluidic microchannels is studied. Compared with macroscopic turbulence control on traditional micro-structured microfluidic surface, the novel FNA-engineered microfluidic interface successfully constructs a 3D reaction space at nanoscale by raising DNA probes away from the surface. This FNA interface dramatically improves the reaction kinetics during molecular recognition due to extremely ordered orientation, configuration and density of DNA probes on the surface. Finally, the FNA-engineered interface is applied in a novel multi-functional microfluidic platform, towards a "one-stop" assay of Escherichia coli O157: H7 (E. coli O157: H7), integrating capture, release, enrichment, cell culture and antimicrobial susceptibility testing (AST). With the FNA-aptamer probe, we achieved an enhanced bacterial detecting efficiency (10 CFU/mL) plus excellent selectivity and precision. The appicability was strongly demonstrated when the biosensor was successfully applied in real samples, including the analysis of antibiotic susceptibility and minimum inhibitory concentration (MIC) of E. coli O157: H7 among different antibiotics. The application of FNA interface will open a wide avenue for the development of microfluidic biosensors for other pathogenic microorganisms or circulating tumor cells (CTC) simply by changing the aptamers.

Microfluidic Technology for Clinical Applications of Exosomes

Exosomes, a type of nanovesicle, are distinct cellular entities specifically capable of carrying various cargos between cells. It has been hypothesized that exosomes, as an enriched source of biomolecules, may serve as biomarkers for various diseases. This review introduces general aspects of exosomes, presents the challenges in exosome research, discusses the potential of exosomes as biomarkers, and describes the contribution of microfluidic technology to enable their isolation and analysis for diagnostic and disease monitoring. Additionally, clinical applications of exosomes for diagnostic purposes are also summarized.

Microfluidic-based vascularized microphysiological systems

Microphysiological systems have emerged in the last decade to provide an alternative to in vivo models in basic science and pharmaceutical research. In the field of vascular biology, in particular, there has been a lack of a suitable in vitro model exhibiting a three-dimensional structure and the physiological function of vasculature integrated with organ-on-a-chip models. The rapid development of organ-on-a-chip technology is well positioned to fulfill unmet needs. Recently, functional integration of vasculature with diverse microphysiological systems has been increasing. This recent trend corresponds to emerging research interest in how the vascular system contributes to various physiological and pathological conditions. This innovative platform has undergone significant development, but adoption of this technology by end-users and researchers in biology is still a work in progress. Therefore, it is critical to focus on simplification and standardization to promote the distribution and acceptance of this technology by the end-users. In this review, we will introduce the latest developments in vascularized microphysiological systems and summarize their outlook in basic research and drug screening applications.

Application of Nanotechnology in Food Science: Perception and Overview

Recent innovations in nanotechnology have transformed a number of scientific and industrial areas including the food industry. Applications of nanotechnology have emerged with increasing need of nanoparticle uses in various fields of food science and food microbiology, including food processing, food packaging, functional food development, food safety, detection of foodborne pathogens, and shelf-life extension of food and/or food products. This review summarizes the potential of nanoparticles for their uses in the food industry in order to provide consumers a safe and contamination free food and to ensure the consumer acceptability of the food with enhanced functional properties. Aspects of application of nanotechnology in relation to increasing in food nutrition and organoleptic properties of foods have also been discussed briefly along with a few insights on safety issues and regulatory concerns on nano-processed food products.

Novel Modifications to Carbon-Based Electrodes to Improve the Electrochemical Detection of Dopamine

In this work, we describe three simple modifications to carbon electrodes that were found to improve the detection of an exemplar neurotransmitter (dopamine) in the presence of physiological interferents (ascorbic acid and/or uric acid). First, the electro-oxidation of ascorbic acid, as a pretreatment, at boron-doped diamond electrode (BDE) interfaces is studied. This treatment did suppress the detection of ascorbic acid oxidation signal, but only in a manner suitable for single-use detection of high concentrations of dopamine (i.e., > 1 μM). Second, the hydrogenation of BDE by electrochemical cathodic treatment and plasma hydrogenation was investigated. Large cathodic, applied potentials (i.e., > - 5 V) and hydrogen plasma pretreatment of BDE lead to the partial and complete oxidization of ascorbic acid before dopamine, respectively. The consequence at hydrogen-plasma treated BDE is the complete electrochemical separation of these two species without any typical catalytic reactions between the analytes. Third, the modification of glassy carbon electrodes with carbon black nanoparticles is explored. This modification enables the simultaneous detection of ascorbic acid, dopamine and uric acid, significantly enhancing the sensitivity of dopamine. Dopamine was best detected using the unconventional route of detecting 5,6-dihydroxyindole, which is made possible by use of carbon-black nanoparticles. The potential of all three studied modifications to be of electroanalytical use is highlighted throughout this work.

Ultrasensitive microfluidic analysis of circulating exosomes using a nanostructured graphene oxide/polydopamine coating

Exosomes are cell-derived nano-sized vesicles that have been recently recognized as new mediators for many cellular processes and potential biomarkers for non-invasive disease diagnosis and the monitoring of treatment response. To better elucidate the biology and clinical value of exosomes, there is a pressing need for new analytical technologies capable of the efficient isolation and sensitive analysis of such small and molecularly diverse vesicles. Herein, we developed a microfluidic exosome analysis platform based on a new graphene oxide/polydopamine (GO/PDA) nano-interface. To the best of our best knowledge, we report for the first time, the GO-induced formation of a 3D nanoporous PDA surface coating enabled by the microfluidic layer-by-layer deposition of GO and PDA. It was demonstrated that this nanostructured GO/PDA interface greatly improves the efficiency of exosome immuno-capture, while at the same time effectively suppressing non-specific exosome adsorption. Based on this nano-interface, an ultrasensitive exosome ELISA assay was developed to afford a very low detection limit of 50 μL(-1) with a 4 log dynamic range, which is substantially better than the existing methods. As a proof of concept for clinical applications, we adapted this platform to discriminate ovarian cancer patients from healthy controls by the quantitative detection of exosomes directly from 2 μL plasma without sample processing. Thus, this platform could provide a useful tool to facilitate basic and clinical investigations of exosomes for non-invasive disease diagnosis and to aid precision treatment.

Nanotechnology: a future tool to improve quality and safety in meat industry

Nanotechnology refers to the new aspect of science modifies its physical, chemical and biological properties leading to new applications or enhanced utility. Keeping the pace with other industries, the meat industry has adopted the new technology in a range of applications to improve the quality and safety of products. The potential applications include the improvement in the tastes, texture, flavor, production of low fat and salt products, enhanced nutrient absorption, improved packaging techniques and better pathogen detection system. However some safety issues need to be addressed before taking a ride on the technology at the full throttle.

Nanostructured sensors for biomedical applications--a current perspective

Nanostructured sensors have unique capabilities that can be tailored to advantage in advancing the diagnosis, monitoring and cure of several diseases and health conditions. This report aims at providing a current perspective on, (a) the emerging clinical needs that defines the challenges to be addressed by nanostructured sensors, with specific emphasis on early stage diagnosis, drug-diagnostic combinations, and predictive models to design therapy, (b) the emerging industry trends in in vitro diagnostics, mobile health care, high-throughput molecular and cell-based diagnostic platforms, and (c) recent instances of nanostructured biosensors, including promising sensing concepts that can be enhanced using nanostructures that carry high promise towards catering to the emerging clinical needs, as well as the market/industry trends.

Microfluidic platforms for the investigation of intercellular signalling mechanisms

Intercellular signalling has been identified as a highly complex process, responsible for orchestrating many physiological functions. While conventional methods of investigation have been useful, their limitations are impeding further development. Microfluidics offers an opportunity to overcome some of these limitations. Most notably, microfluidic systems can emulate the in-vivo environments. Further, they enable exceptionally precise control of the microenvironment, allowing complex mechanisms to be selectively isolated and studied in detail. There has thus been a growing adoption of microfluidic platforms for investigation of cell signalling mechanisms. This review provides an overview of the different signalling mechanisms and discusses the methods used to study them, with a focus on the microfluidic devices developed for this purpose.

A prospective overview of the essential requirements in molecular modeling for nanomedicine design

Nanotechnology has presented many new challenges and opportunities in the area of nanomedicine design. The issues related to nanoconjugation, nanosystem-mediated targeted drug delivery, transitional stability of nanovehicles, the integrity of drug transport, drug-delivery mechanisms and chemical structural design require a pre-estimated and determined course of assumptive actions with property and characteristic estimations for optimal nanomedicine design. Molecular modeling in nanomedicine encompasses these pre-estimations and predictions of pertinent design data via interactive computographic software. Recently, an increasing amount of research has been reported where specialized software is being developed and employed in an attempt to bridge the gap between drug discovery, materials science and biology. This review provides an assimilative and concise incursion into the current and future strategies of molecular-modeling applications in nanomedicine design and aims to describe the utilization of molecular models and theoretical-chemistry computographic techniques for expansive nanomedicine design and development.

Detecting the effect of targeted anti-cancer medicines on single cancer cells using a poly-silicon wire ion sensor integrated with a confined sensitive window

A mold-cast polydimethylsiloxane (PDMS) confined window was integrated with a poly-silicon wire (PSW) ion sensor. The PSW sensor surface inside the confined window was coated with a 3-aminopropyltriethoxysilane (γ-APTES) sensitive layer which allowed a single living cell to be cultivated. The change in the microenvironment due to the extracellular acidification of the single cell could then be determined by measuring the current flowing through the PSW channel. Based on this, the PSW sensor integrated with a confined sensitive window was used to detect the apoptosis as well as the effect of anti-cancer medicines on the single living non-small-lung-cancer (NSLC) cells including lung adenocarcinoma cancer cells A549 and H1299, and lung squamous-cell carcinoma CH27 cultivated inside the confined window. Single human normal cells including lung fibroblast cells WI38, lung fibroblast cells MRC5, and bronchial epithelium cell Beas-2B were tested for comparison. Two targeted anti-NSCLC cancer medicines, Iressa and Staurosporine, were used in the present study. It was found that the PSW sensor can be used to accurately detect the apoptosis of single cancer cells after the anti-cancer medicines were added. It was also found that Staurosporine is more effective than Iressa in activating the apoptosis of cancer cells.

The applications of nanotechnology in food industry

Nanotechnology has the potential of application in the food industry and processing as new tools for pathogen detection, disease treatment delivery systems, food packaging, and delivery of bioactive compounds to target sites. The application of nanotechnology in food systems will provide new methods to improve safety and the nutritional value of food products. This article will review the current advances of applications of nanotechnology in food science and technology. Also, it describes new current food laws for nanofood and novel articles in the field of risk assessment of using nanotechnology in the food industry.

Engineering of a microfluidic cell culture platform embedded with nanoscale features

Cells residing in a microenvironment interact with the extracellular matrix (ECM) and neighboring cells. The ECM built from biomacromolecules often includes nanotopography. Through the ECM, interstitial flows facilitate transport of nutrients and play an important role in tissue maintenance and pathobiology. To create a microenvironment that can incorporate both nanotopography and flow for studies of cell-matrix interactions, we fabricated microfluidic channels endowed with nanopatterns suitable for dynamic culture. Using polymer thin film technology, we developed a versatile stitching technique to generate a large area of nanopatterned surface and a simple microtransfer assembly technique to assemble polydimethylsiloxane-based microfluidics. The cellular study showed that both nanotopography and fluid shear stress played a significant role in adhesion, spreading, and migration of human mesenchymal stem cells. The orientation and deformation of cytoskeleton and nuclei were regulated through the interplay of these two cues. The nanostructured microfluidic platform provides a useful tool to promote the fundamental understanding of cell-matrix interactions and may be used to regulate the fate of stem cells.

Controlled induction of distributed microdeformation in wounded tissue via a microchamber array dressing

Mechanical stimuli are known to play an important role in determining the structure and function of living cells and tissues. Recent studies have highlighted the role of mechanical signals in mammalian dermal wound healing. However, the biological link between mechanical stimulation of wounded tissue and the subsequent cellular response has not been fully determined. The capacity for researchers to study this link is partially limited by the lack of instrumentation capable of applying controlled mechanical stimuli to wounded tissue. The studies outlined here tested the hypothesis that it was possible to control the magnitude of induced wound tissue deformation using a microfabricated dressing composed of an array of open-faced, hexagonally shaped microchambers rendered in a patch of silicone rubber. By connecting the dressing to a single vacuum source, the underlying wounded tissue was drawn up into each of the microchambers, thereby inducing tissue deformation. For these studies, the dressings were applied to full-thickness murine dermal wounds with 200 mmHg vacuum for 12 h. These studies demonstrated that the dressing was capable of inducing wound tissue deformation with values ranging from 11 to 29%. Through statistical analysis, the magnitude of the induced deformation was shown to be a function of both microchamber height and width. These results demonstrated that the dressing was capable of controlling the amount of deformation imparted in the underlying tissue. By allowing the application of mechanical stimulation with varying intensities, such a dressing will enable the performance of sophisticated mechanobiology studies in dermal wound healing.

Analysis of nonadherent apoptotic cells by a quantum dots probe in a microfluidic device for drug screening

This technical note describes a facile technique to screen some anticancer drugs and evaluate their effects on nonadhesive leukemic cells in an easily fabricated microfluidic device by utilizing the Annexin V conjugated quantum dots as apoptosis detection probes. The cell immobilizing structures and gradient-generating channels were integrated within the device which was fabricated in one-single step. The nonadhesive leukemic HL-60 cells can be felicitously immobilized and cultured on the dam structures at a proper lateral pressure. We then delivered Annexin V functionalized quantum dots which can readily bind to the outer membrane of apoptotic cells and distinguish the apoptosis from unaffected cells with single cell level resolution. The diffusion time of quantum dots reduced to 5 min before imaging. The capabilities of evaluating drug effect on HL-60 cell line have been shown in both population way and individual cell level. The technique presented herein can bridge the gap between the quantum dots based in vitro cell imaging and the analysis of individual apoptotic cell in a microfluidic system, allows an easy operating protocol to screen some clinically available anticancer drugs.

Current application of micro/nano-interfaces to stimulate and analyze cellular responses

Microfabrication technologies have a high potential for novel approaches to access living cells at a cellular or even at a molecular level. In the course of reviewing and discussing the current application of microinterface systems including nanointerfaces to stimulate and analyze cellular responses with subcellular resolution, this article focuses on interfaces based on microfluidics, nanoparticles, and scanning electrochemical microscopy (SECM). Micro/nanointerface systems provide a novel, attractive means for cell study because they are capable of regulating and monitoring cellular signals simultaneously and repeatedly, leading us to an enhanced understanding and interpretation of cellular responses. Therefore, it is hoped that the integrated micro/nanointerfaces presented in this review will contribute to future developments of cell biology and facilitate advanced biomedical applications.

Bio-Microfluidics: Overview

With a view to establish unique interfacial synergistic interactions between two seemingly distant fields of microfluidics and biology, Bio-microfluidics has become a progressive arena of research in recent times. Bio-microfluidic tools in the format of lab-on-a-chip devices have been extensively utilized to uncouth hitherto un-illuminated regions of cellular-molecular biology, biotechnology and biomedical engineering. This chapter elaborately delineates the linking between the fundamental microscale physics and biologically relevant physico-chemical events and how, in practice, these relations are exploited in microfluidic devices. Finally, potential directions of future biomicrofluidic research are also discussed.

A novel permalloy based magnetic single cell micro array

Devices capable of automatically aligning cells onto geometrical arrays are of great interest to biomedical researchers. Such devices can facilitate the study of numerous cells while the cells remain physically separated from one another. In this way, cell arrays reduce cell-to-cell interactions while the cells are all subjected to common stimuli, which allows individual cell behaviour to be revealed. The use of arrays allows for the parallel analysis of single cells, facilitates data logging, and opens the door to the use of automated machine-based single cell analysis techniques. A novel permalloy based magnetic single cell micro array (MSCMA) is presented in this paper. The MSCMA creates an array of magnetic traps by generating magnetic flux density peaks at predefined locations. When using cells labelled with immunomagnetic labels, the cells will interact with the magnetic fields, and can be captured at the magnetic trap sites. Prototypes of the MSCMA have been successfully fabricated and tested using both fixed and live Jurkat cells (10 microm average diameter) that were labelled. The prototypes performed as predicted during experimental trials. The experimental results show that the MSCMA can randomly array up to 136 single cells per square mm. The results also show that the number of single cells captured is a function of the trap site density of the MSCMA design and the cell density in the fluid sample.

Microfluidics technology for systems biology research

Systems biology is a discipline seeking to understand the emergent behavior of a biological system by integrative modeling of the interactions of the molecular elements. The success of the approach relies on the quality of the biological data. In this chapter, we discuss how a systems biology laboratory can apply microfluidics technology to acquire comprehensive, systematic, and quantitative data for their modeling needs.

Bioengineering and Bioinformatics Summer Institutes: meeting modern challenges in undergraduate summer research

Summer undergraduate research programs in science and engineering facilitate research progress for faculty and provide a close-ended research experience for students, which can prepare them for careers in industry, medicine, and academia. However, ensuring these outcomes is a challenge when the students arrive ill-prepared for substantive research or if projects are ill-defined or impractical for a typical 10-wk summer. We describe how the new Bioengineering and Bioinformatics Summer Institutes (BBSI), developed in response to a call for proposals by the National Institutes of Health (NIH) and the National Science Foundation (NSF), provide an impetus for the enhancement of traditional undergraduate research experiences with intense didactic training in particular skills and technologies. Such didactic components provide highly focused and qualified students for summer research with the goal of ensuring increased student satisfaction with research and mentor satisfaction with student productivity. As an example, we focus on our experiences with the Penn State Biomaterials and Bionanotechnology Summer Institute (PSU-BBSI), which trains undergraduates in core technologies in surface characterization, computational modeling, cell biology, and fabrication to prepare them for student-centered research projects in the role of materials in guiding cell biology.

Cells on chips

Microsystems create new opportunities for the spatial and temporal control of cell growth and stimuli by combining surfaces that mimic complex biochemistries and geometries of the extracellular matrix with microfluidic channels that regulate transport of fluids and soluble factors. Further integration with bioanalytic microsystems results in multifunctional platforms for basic biological insights into cells and tissues, as well as for cell-based sensors with biochemical, biomedical and environmental functions. Highly integrated microdevices show great promise for basic biomedical and pharmaceutical research, and robust and portable point-of-care devices could be used in clinical settings, in both the developed and the developing world.