Investigation of the Holding Capability of the Dielectrophoretic Gate and Sorter System for Biodetection

The dielectrophoretic gate and sorter system has been widely applied for preconcentrating and sorting of bioparticles for biodetection. In such systems, the dielectrophoretic force is generated by applying an AC electric field on the three dimensional electrode systems (containing a pair of electrodes on the top and bottom of the channel). Particles are held and sorted by balancing the DEP force with the hydrodynamic drag force. The holding capability is very important for such systems because it determines the preconcentration and sorting efficiency. In this paper, we investigate the holding capability of a simple dielectrophoretic gate system. Initially, a three dimensional numerical scheme was introduced to estimate the holding capability and was further validated by comparing with experimental results. Second, we systematically investigated the effects of the phase difference between the top and bottom electrodes;the height and width of the channel, and the relative position and size of top and bottom electrodes. The results demonstrated that the maximum holding capability is reached when the phase difference between the top and bottom electrodes is around 180o. The results also show that the holding capability varied with the size and relative position of electrodes on the top and bottom, and the maximum holding capability is obtained when the top and bottom electrodes had the same size and the centers of both electrodes overlapped.

Superwettable interface towards biodetection in confined space

The detection of biomarkers with both high sensitivity and specificity is crucial for the diagnosis and treatment of related diseases.However,many current detections employ ex-situ detection method and non-confined condition,thus have many problems,which may eventually lead to inaccurate detection results.Compared to detection in non-confined space,detection in confined space can better reflect the real in-vivo situation.Therefore,the construction of detection for target molecules in confined space has great significance for both theoretical research and practical application.To realize the detection of target molecules in confined space,the probes should accurately enter the confined space where the target molecules reside and interact with the interface.Thus,how to explore and utilize the properties of the interface(for example,bioinspired superwettability)has always been a hot and difficult topic in this field.Herein,the recent advances and our efforts in recent 10 years on detection of bio-target molecules in confined space with superwettable interface have been introduced from the perspective of the detection methods.The suitable and most widely employed detection methods for target molecules in confined spaces are introduced firstly.Then,recent progresses for related detections based on visual,optical,and electrochemical detection methods are presented successively.Finally,the perspective for detection in confined space is discussed for the future development of biochemical detection.

Handheld high-throughput plasmonic biosensor using computational on-chip imaging

We demonstrate a handheld on-chip biosensing technology that employs plasmonic microarrays coupled with a lens-free computational imaging system towards multiplexed and high-throughput screening of biomolecular interactions for point-of-care applications and resource-limited settings.This lightweight and field-portable biosensing device,weighing 60 g and 7.5 cm tall,utilizes a compact optoelectronic sensor array to record the diffraction patterns of plasmonic nanostructures under uniform illumination by a single-light emitting diode tuned to the plasmonic mode of the nanoapertures.Employing a sensitive plasmonic array design that is combined with lens-free computational imaging,we demonstrate label-free and quantitative detection of biomolecules with a protein layer thickness down to 3 nm.Integrating large-scale plasmonic microarrays,our on-chip imaging platform enables simultaneous detection of protein mono-and bilayers on the same platform over a wide range of biomolecule concentrations.In this handheld device,we also employ an iterative phase retrieval-based image reconstruction method,which offers the ability to digitally image a highly multiplexed array of sensors on the same plasmonic chip,making this approach especially suitable for high-throughput diagnostic applications in field settings.

Versatile metal graphitic nanocapsules for SERS bioanalysis

The novel graphitic nanomaterial of metal graphitic nanocapsules(MGNs) with superior stability, unique optical properties and biocompatibility possess great potential in biomedical and bioanalytical applications. The graphitic shell can quench the background fluorescence interference from external environments via a fluorescence resonance energy transfer(FRET) process and even avoid unnecessary reactions catalyzed by inner metal core. The graphitic shell with several characteristic Raman bands itself can act as Raman signal probe or internal standard(IS), especially the 2D-band within the cellular Raman-silent region helps to reduce the interference signals from external conditions. The present context attempts to give a comprehensive overview about the preparation and unique properties of MGNs as well as their applications in SERS biodetection and bioimaging.

Nanocatalytic Medicine of Iron-Based Nanocatalysts

Iron can be found in all mammalian cells and is of critical significance to diverse cellular activities within human bodies.Widespread applications and the underlying chemical and biological fundamental explorations of iron-based nanomaterials,especially on the biomedical frontiers,have attracted growing interests most recently in the community.In this review,we focus on the catalytic performance of iron-based nanomaterials(termed as nanocatalysts,abbreviated as NCs)and their nanocatalytic biomedical applications in Fenton nanocatalytic therapeutics,nanocatalytic oxygenation-enabled therapeutics,and nanocatalytic peroxidation-enabled biodetections.Fabrication methodologies of the iron-based NCs are also summarized along with their applications.Representative therapeutic performance against malignant tumors,Alzheimer’s disease(and other pathological abnormalities),and nanocatalyticbased biodetection are discussed.Finally,future development prospects of the iron-based NCs are surveyed,aiming to deliver a brighter future for iron-based NCs in nanocatalytic medicine.

Developing sensor materials for screening intestinal diseases

Intestinal diseases that have high mortality and morbidity rates and bring huge encumbrance to the public medical system and economy worldwide,have always been the focus of clinicians and scientific researchers.Early diagnosis and intervention are valuable in the progression of many intestinal diseases.Fortunately,the emergence of sensor materials can effectively assist clinical early diagnosis and health monitoring.By accurately locating the lesion and sensitively analyzing the level of disease markers,these sensor materials can help to precisely diagnose the stage and state of lesions,thereby avoiding delayed treatment.In this review,we provide comprehensive and in-depth knowledge of diagnosing and monitoring intestinal diseases with the assistance of sensor materials,particularly emphasizing their design and application in bioimaging and biodetection.This review is dedicated to conveying practical applications of sensor materials in the intestine,critical analysis of their mechanisms and applications and discussion of their future roles in medicine.We believe that this review will promote multidisciplinary communication between material science,medicine and relevant engineering fields,thus improving the clinical translation of sensor materials.