Visible light induced electropolymerization of suspended hydrogel bioscaffolds in a microfluidic chip

Recent advances in optically induced di-electrophoresis and its biomedical applications

The development of the micro/nano science and technology has promoted the evolvement of human civilization tremendously. The advancement of the micro/nano science and technology highly depends on the progress of the micro/nano manipulation techniques, and the micro/nano-scaled manipulation level is the critical sign of the micro/nano science and technology. This review, aimed at the demand and the challenge of the micro/nano material and biomedical fields and related to the scientific issues and implementation techniques of the optically induced di-electrophoresis (ODEP). We explained its working principle, manipulating method, and influencing factors of ODEP force to a certain extent. A number of application fields based-ODEP technology and specific applications so far are summarized and reviewed. Finally, some perspectives are provided on current development trends, future research directions, and challenges of ODEP.

Optoelectronic tweezers: a versatile toolbox for nano-/micro-manipulation

This review covers the fundamentals, recent progress and state-of-the-art applications of optoelectronic tweezers technology, and demonstrates that optoelectronic tweezers technology is a versatile and powerful toolbox for nano-/micro-manipulation.

Mesoporous nanomaterial-assisted hydrogel double network composite for mixed-mode liquid chromatography

By introducing functional groups such as quaternary amine groups, sulfonic acid groups, triazine groups, and other mespore nanomaterials into the hydrogel, better separation effect of some organic framework materials has been obtained. Due to a reasonable design and preparation strategy, the hydrogel composite-modified silica can be used in the selective separation of various analytes such as pesticides, alkylbenzenes, polycyclic aromatic hydrocarbons, nucleosides/bases, benzoic acids, antibiotics, and carbohydrates. Through the exploration of chromatographic retention behavior, it is proved that the column can be used in mixed-mode liquid chromatography. The intra-day relative standard deviation for retention time of this new stationary phase is 0.12-0.16% (n = 10), and the inter-day relative standard deviation is less than 0.39% (n = 5). This new stationary phase can also be used for separation in complex samples. The limit of detection (LOD) for chlorotoluron in farm irrigation water is 0.21 µg/L and the linear range is 2-250 µg/L. After optimizing the chromatographic conditions, the highest efficiency of the hydrogel column in RPLC and HILIC modes has reached 32,400 plates/m (chlorobenzuron) and 41,300 plates/m (galactose). This new type of hydrogel composite is a porous network material with flexible functional design and simple preparation method and its application has been expanded in liquid chromatography separation successfully. The hydrogel composed of triallyl cyanate cross-linking agent and 3-(2-(methacryloyloxy) ethyl) dimethylamine) propane-1-sulfonate (SBMA) monomer which were co-modified on the surface of mesoporous silica with MOF-919 for separation in mixed-mode liquid chromatography.

Design and Fabrication of Organ-on-Chips: Promises and Challenges

The advent of the miniaturization approach has influenced the research trends in almost all disciplines. Bioengineering is one of the fields benefiting from the new possibilities of microfabrication techniques, especially in cell and tissue culture, disease modeling, and drug discovery. The limitations of existing 2D cell culture techniques, the high time and cost requirements, and the considerable failure rates have led to the idea of 3D cell culture environments capable of providing physiologically relevant tissue functions in vitro. Organ-on-chips are microfluidic devices used in this context as a potential alternative to in vivo animal testing to reduce the cost and time required for drug evaluation. This emerging technology contributes significantly to the development of various research areas, including, but not limited to, tissue engineering and drug discovery. However, it also brings many challenges. Further development of the technology requires interdisciplinary studies as some problems are associated with the materials and their manufacturing techniques. Therefore, in this paper, organ-on-chip technologies are presented, focusing on the design and fabrication requirements. Then, state-of-the-art materials and microfabrication techniques are described in detail to show their advantages and also their limitations. A comparison and identification of gaps for current use and further studies are therefore the subject of the final discussion.

A Review on Optoelectrokinetics-Based Manipulation and Fabrication of Micro/Nanomaterials

Optoelectrokinetics (OEK), a fusion of optics, electrokinetics, and microfluidics, has been demonstrated to offer a series of extraordinary advantages in the manipulation and fabrication of micro/nanomaterials, such as requiring no mask, programmability, flexibility, and rapidness. In this paper, we summarize a variety of differently structured OEK chips, followed by a discussion on how they are fabricated and the ways in which they work. We also review how three differently sized polystyrene beads can be separated simultaneously, how a variety of nanoparticles can be assembled, and how micro/nanomaterials can be fabricated into functional devices. Another focus of our paper is on mask-free fabrication and assembly of hydrogel-based micro/nanostructures and its possible applications in biological fields. We provide a summary of the current challenges facing the OEK technique and its future prospects at the end of this paper.

Optoelectrokinetics-based microfluidic platform for bioapplications: A review of recent advances

The introduction of optoelectrokinetics (OEK) into lab-on-a-chip systems has facilitated a new cutting-edge technique-the OEK-based micro/nanoscale manipulation, separation, and assembly processes-for the microfluidics community. This technique offers a variety of extraordinary advantages such as programmability, flexibility, high biocompatibility, low-cost mass production, ultralow optical power requirement, reconfigurability, rapidness, and ease of integration with other microfluidic units. This paper reviews the physical mechanisms that govern the manipulation of micro/nano-objects in microfluidic environments as well as applications related to OEK-based micro/nanoscale manipulation-applications that span from single-cell manipulation to single-molecular behavior determination. This paper wraps up with a discussion of the current challenges and future prospects for the OEK-based microfluidics technique. The conclusion is that this technique will allow more opportunities for biomedical and bioengineering researchers to improve lab-on-a-chip technologies and will have far-reaching implications for biorelated researches and applications in the future.

Light-addressable electrochemistry at semiconductor electrodes: redox imaging, mask-free lithography and spatially resolved chemical and biological sensing

Spatial confinement of electrochemical reactions at solid/liquid interfaces is a mature area of research, and a central theme from cell biology to analytical chemistry. Monitoring or manipulating the kinetics of a charge transfer reaction in 2D is generally achieved using scanning electrochemical microscopy or multielectrode arrays, techniques that rely on moving physical probes or on a network of electrical connections. This tutorial is introducing concepts and instruments to confine faradaic electrochemical reactions in 2D without resorting to the mechanical movement of a probe, and with the simple design of one semiconducting electrode, one electrical lead and a single-channel potentiostat. We provide a theoretical background of semiconductor electrochemistry, and describe the use of localised visible light stimuli on photoconductor/liquid and semiconductor/liquid interfaces to address electrical conductivity - hence chemical reactivity - only at one specific site defined by the experimentalist. This enables shifting of the tenet of one electrode/one wire towards one wire/many electrodes. We discuss the applications of this emerging platform in the context of surface chemistry patterning, redox imaging, chemical and biological sensing, generating chemical gradients, electrocatalysis, nanotechnology and cell biology.