This paper reports development of a smartphone-based multispectral imaging system and its potential for diagnosis of various skin diseases quantitatively. To date, a variety of mobile devices have emerged as healthcare tools. In particular, when they are combined with advanced optical imaging techniques such as multispectral imaging techniques, it would be very beneficial for early diagnosis of malignant and non-malignant skin diseases and further quantitative monitoring of prognosis of the diseases after their treatment in ubiquitous environments. Recently, various mobile devices based on a smartphone gained much attention [1-3]. However, most of the devices were based on RGB color imaging as well as conventional image processing techniques and thus they have several limitations such as low spectral resolutions and less versatility when used to diagnose various skin diseases [4-6 22, 23]. To overcome these limitations, the development of a more advanced mobile skin diagnosis system with high quantitative capabilities must be achieved. Thus, we demonstrate development of a novel smartphone-based multispectral imaging system and its potentials of smartphone-based multispectral imaging and analysis for mobile diagnosis of various skin diseases. In this study, we underlie how to develop a smartphone-based multispectral imaging system. In particular, its unique calibration method, which is robust in mobile environments, is introduced. We also investigate its potentials for mobile diagnosis of various skin diseases including acne, seborrheic dermatitis, psoriasis, and etc. It was here found that the smartphone-based multispectral imaging and analysis using the system allowed us to quantitatively monitor acne regions during their treatments with benzoyl peroxide. The changes in the size and the severity of acne regions during the benzoyl peroxide treatments have been quantified using the system. Also, it was employed to discriminate between seborrheic dermatitis and psoriasis occurred on the scalp. The accuracy in discrimination between them at their early stage was found to be over 70%. Therefore, the results suggested that it has the potential as a mobile diagnosis tool for detection of both seborrheic dermatitis and psoriasis with high sensitivity and specificity at ubiquitous environments. Furthermore, we discuss its potential as a healthcare tool for recommendation of personalized cosmetics. Altogether, the smartphone-based multispectral imaging and analysis are highly useful for the early- and pre-detection of various skin diseases as well as quantitative/continuous monitoring of skin diseases with a low cost at home. Therefore, the results shown in this study demonstrate that it has great potential as a mobile-healthcare device to diagnose and manage skin lesions. It may furthermore be applicable to the detection of other malignant skin disease such as melanoma in ubiquitous environments.

Gold nanoclusters (GNCs), due to their super high specific surface, have extraordinary high capacity to carry nucleic acids such as siRNA. In recent studies, we focused on targeting nervous environment of tumors because accumulating evidence indicates that the nerves promote tumor development and metastasis. Pancreatic cancer, one of the deadliest human cancers, is closely  related to nervous microenvironment. Pancreatic cancer actively promotes the growth of neurites and stimulate the neurogenesis via the expression of neurotrophic factors such as nerve growth factors (NGFs). Thus, the suppression of NGF expression may inhibit the development of pancreatic cancer. Among various nanomaterials, GNCs had the strongest capacity to conjugate siRNA (226 µmol siRNA per g GNCs). Thus, we used GNCs as nanocarrier to deliver siRNA of NGF (GNC-siRNA) to treat pancreatic cancer. The GNC-siNGF increases the stability of siRNA in serum, prolonges the circulation lifetime of siRNA in blood, and enhances the cellular uptake and tumor accumulation of siRNA. The GNC-siNGF potently down-regulated the NGF expression in Panc-1 cells and in pancreatic tumors, and effectively inhibited the tumor progression in three pancreatic tumor models (subcutaneous model, orthotopic model, and patient-derived xenograft (PDX) model) without adverse effects. Our study demonstrate that knockdown of NGF expression by GNC-siNGF is a promising therapeutic direction for pancreatic cancer.

Membrane filtration has been increasingly used in water purification and wastewater treatment and reuse. However, membrane fouling is still a major problem to the membrane filtration process. Membrane fouling occurs in the boundary layer at the membrane surface where impurities rejected by the membrane accumulate and form a dynamic fouling layer. Owing to the lacking of experimental means, this dynamic fouling process that has not been well characterized. In this study, the micro-particle image velocimetry (MicroPIV) technique was utilized to achieve in-situ investigation of the membrane fouling dynamics near the membrane surface during the crossflow ultrafiltration in a flat-sheet membrane cell. A membrane sheet was placed on the bottom of the crossflow filtration cell. Fluorescent latex nanoparticles sizing 600 nm were used as particulate impurities or tracers in the feed solution. When excited by laser, the nanoparticles can emit fluorescent light. A high-speed scientific CCD camera equipped with a microscopic objective lens was employed to take photos of the flow field over the membrane surface during the ultrafiltration process, while the fluorescent signals from the nanoparticles were captured by the camera. With the MicroPIV technique, the dynamic process of fouling layer formation was directly observed. By further image processing, the thickness and the concentration of the dynamic fouling layer were well determined.

In this study, we report a highly sensitive label-free biosensing platform combining an electrokinetic concentrator with a silicon microring resonator in a microfluidic chip. Electrokinetic concentration of biomolecules increases the concentration of charged biomolecules locally on the microring resonator inside a microfluidic channel and enhances the detection speed and sensitivity. Based on this unique combination of electrokinetics and silicon photonics, we have built an ultrasensitive label-free sensing platform in a multiplexed format for a direct and rapid analysis of various biomarkers such as DNA and RNA molecules that are becoming increasingly important in liquid biopsy. In our electrokinetic concentration scheme, two reservoirs are connected by both a conductive polymer membrane, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), directly printed on top of a polydimethylsiloxane (PDMS) microfluidic channel. For integration, the microfluidic concentrator chip is aligned and reversibly sealed with a silicon substrate containing an array of microrings. We demonstrated the performance of this hybrid optofluidic-electrokinetic sensing platform for DNA from an initial concentration of C₀ = 100 nM and its enhanced hybridization result on MO (“Morpholinos”, a class of uncharged DNA mimics) capture probes. Our result validated the effectiveness of electrokinetic concentration for MO-based detection of DNA, leading to significantly faster DNA hybridization to MO capture probes even in the sub-nanomolar target concentration regimes that usually require extensive incubation times or simply remain undetectable. Once fully developed, our multiplexed concentrator-enhanced micro resonators could become an indispensable tool to detect genes expressed at even very low levels more rapidly and reproducibly.

With increasing demand for flexible and wearable electronic devices, flexible energy storage devices have received considerable attention for their application in this emerging field. Recently, many efforts have been dedicated to develop flexible solid-state supercapacitors because of their high power density, long cycle life and high safety. The two typical flexible supercapacitors are flexible planar supercapacitors and fiber supercapacitors. Compared with the planar supercapacitors, fiber supercapacitors which are weavable exhibit promising applications in flexible and wearable electronic devices. In this work, solid-state, coaxial fiber supercapacitors using Chinese ink as active materials were designed, manufactured and characterized. This kind of fiber supercapacitors show a good flexibility and weavability, and the energy storage performance of the fiber supercapacitors can be improved by mixing the Chinese ink with the ball-milled carbon. These kinds of flexible energy storage fibers can be woven into other fabrics to make smart textile materials for a desired use.

Big data is a hot topic today, not only because the world is awash in digital data, but also the fresh information can be mined from the data. But the big data problem isn’t limited to analytics; it also includes data capture, storage and transmission. Compressive sampling (CS) has attracted considerable attention as a novel data sampling technique and widely applied in diverse fields including wideband spectrum sensing and biomedical imaging in recent years. Compared with traditional electric CS systems, photonic-assisted CS technique utilizes can significantly reduce the sampling rate of the back-end analog-to-digital converter (ADC), highly compress the big data. With these techniques, we demonstrated one-dimensional and 2-dimensional high-speed single-pixel imaging systems are implemented with high frame rates three orders of magnitude faster than conventional single-pixel cameras. To show the utility of our scheme in biomedical applications, an imaging flow cytometer with a throughput of 100,000 cells/s is demonstrated, which has settled the big data problem caused by high-throughput image acquisition.

Atherosclerosis, the leading cause of cardiovascular diseases [1–3], is a chronic inflammatory disorder characterized by deposition of cholesterol-containing low-density lipoproteins (LDL) in arterial walls, resulting in blood vessel narrowing and impaired perfusion, and increased leukocyte recruitment [4,5]. Current atherosclerosis in vitro models are 2-dimensional (2D), and fail to reproduce important features of atherogenesis including blood flow-induced shear stress and leukocyte-endothelial interactions [6–7]. Herein, we report a novel biomimetic blood vessel model to study the hemodynamics and leukocyte-endothelial interactions using a tunable, 3-dimensional (3D) endothelial barrier to mimic stenotic plaque. We first characterized the effects of THP-1 monocyte adhesion on activated endothelial monolayer, followed by whole blood perfusion at different channel constrictions to study leukocyte rolling phenotype.

A schematic of the polydimethylsiloxane (PDMS) microfluidic device is shown in Figure 1A. It consists of 3 layers, with a top cell culture chamber (800×100 µm (H×W)) for endothelial (HUVECs) cell culture, and a bottom pneumatic channel (1000×100 µm (H×W)), separated by a thin PDMS membrane (10 µm thick). By varying air flow into the pneumatic channel, the membrane is deflected upwards, thereby creating tunable constrictions in the cell culture chamber (Figure 1B). Endothelial inflammation is mimicked by growing HUVECs to confluency and treating them with tumor necrosis factor-α (TNF-α) to study leukocyte-endothelial interactions in cell culture media (RPMI) and whole blood flow.

We first performed confocal imaging to visualize channel constriction using FITC dye and 3D endothelial “stenotic plaque” (Figure 1B, C). The laminar flow profile over the 3D stenosis was studied from the rolling velocities of 10 µm beads, which varied significantly in the stenosis region (Figure 1D). As observed from Figure 2A, HUVECs expressed higher ICAM-1 due to TNF-α-treatment which facilitated binding of THP-1 cells. Interestingly, distinct adherence patterns of THP-1 for 50% and 80% constrictions was observed under flow (1 dyne/cm²) with increased adherence at the top of the constriction (Figure 2B, C). Upon increasing flow rate to 10 dyne/cm², THP-1 adhesion was reduced in 80% constriction while completely eliminated in 50% constriction. (Figure 2D, E). Finally, whole blood was perfused through the device to study blood flow under stenosis conditions (Figure 3). As expected, significant leukocyte (mostly neutrophils) rolling and adhesion were observed, and average leukocyte rolling velocity was lowest with an 80% constriction (Figure 3D), possibly due to low shear at the top of the stenotic “plaque”. On-going studies are performed to gain better insights into the stenosis-induced hemodynamics effects on leukocyte-endothelial interactions.

In conclusion, the developed atherosclerosis-on-a-chip mimics a physiologically-relevant 3D stenotic blood vessel which enables long-term perfusion cell culture and on-chip visualization of leukocyte-endothelial interactions (rolling, adhesion). This model can also be further developed to study thrombus formation and other endothelial-related dysfunctions in cardiovascular diseases.

Label-free cell analysis is essential to personalized genomics, cancer diagnostics, and drug development as it avoids adverse effects of staining reagents on cellular viability and cell signaling. However, currently available label-free cell assays mostly rely only on a single feature and lack accuracy. Also, the sample size analyzed by these assays is limited due to their low throughput. We have integrated feature extraction and deep learning with high-throughput quantitative phase imaging enabled by photonic time stretch, achieving record high accuracy in label-free blood cell classification. Our system captures quantitative phase and intensity images and extracts 16 biophysical features from each cell. These biophysical measurements form a hyperdimensional feature space in which supervised learning is performed for cell classification. We show classification of white blood T-cells against colon cancer cells, as well as lipid accumulating algal strains for biofuel production. This system opens up a new path to data-driven phenotypic diagnosis and better understanding of the heterogeneous gene expressions in cells.

Fiber-optic sensor has its unique advantages, with a light weight, low loss, and immunity to electromagnetic interference, etc. It can be used in a variety of harsh environments and under high electric field strength to do the environment monitoring. Several fiber sensors design based on fiber Bragg grating (FBG) for numerous physical detections such as temperature, pressure, tilt, vibration, displacement, refractive index [1-3], etc. To the best of our knowledge, there are a few papers using FBGs to sense the bridge scour [4-5].

According to statistics approximately 60 % of all bridge failures reason is caused by water erosion. Nowadays, bridge scour monitoring is an important security issue. In this paper, we propose a new design using FBG sensing element for bridge scour depth monitoring. It is combined with gear mechanisms and fiber optic sensing system (see Figure 1). We design a maximum measurement bridge scour depth of 4 m which has been to meet the needs of bridge safety. The circumference of the pulley is 0.2 meter and the pitch of the threaded screw rod is 1 mm. This dimension is designed to let the threaded screw rod rotates one thread into the screw holes on the left side, when the heavy hammer pulls down the pulley for one rotation. We design to allow the sensor head (silicone rubber) can be applied maximum downward depth of 20 mm. This means that the pulley can be rotated 20 turns. Therefore, the FBG can be protected not easy to break and be achieved the depth measurement of 4 m.

Figure 1 depicts an overview of the fiber-optic sensor measurement system be used for the detection of bridge scour depth. The output beam of a broadband source (BBS) is connected to the first port of optical circulator (OC), and the FBG sensor is connected to the second port of OC.  When the BBS propagating light enters port 1 and emitted from port 2, if the wavelength satisfied the Bragg condition will be reflected back to the OC and exited from port 3 into the optical spectrum analyzer (OSA). Then we can observe the amount of the central wavelength shift of the FBG and obtain the scour depth.

The sensing element of FBG was embedded in silicone rubber which is 14 cm long, 3 cm wide and 1 cm high. And both ends of silicone rubber are fixed to a metal sheet. We experiment with different materials of metal sheet to compare central wavelength shift and measurement ranges. The length, width and height of the metal sheet are 50 mm, 20 mm and 0.3 mm. The metal sheet materials include silicon manganese steel, manganese steel and cyanide tungsten steel. Figure 2 shows the experimental results. In Figure 2, the silicon manganese steel can achieve our design goal that the scour depth up to 4 m will be measured. And the maximum measurement scour depth of cyanide tungsten steel and manganese steel are 3.2 m and 3.6 m, respectively.

We have developed hydroponic culture system for lettuce, which has enabled continuous monitoring of the primary root and the lateral roots as well as the leaves. By using the system and image analysis technique, the total surface area of the roots and the leaves has been estimated in real-time. Our hydroponic culture system has a great potential to reveal the plant physiological state.