Haiyu Huang

Monitoring the progression of metastatic breast cancer on nanoporous silica chips

Breast cancer accounted for 15 per cent of total cancer deaths in female patients in 2010. Although significant progress has been made in treating early-stage breast cancer patients, there is still no effective therapy targeting late-stage metastatic breast cancers except for the conventional chemotherapy interventions. Until effective therapy for later-stage cancers emerges, the identification of biomarkers for the early detection of tumour metastasis continues to hold the key to successful management of breast cancer therapy. Our study concentrated on the low molecular weight (LMW) region of the serum protein and the information it contains for identifying biomarkers that could reflect the ongoing physiological state of all tissues. Owing to technical difficulties in harvesting LMW species, studying these proteins/peptides has been challenging until now. In our study, we have recently developed nanoporous chip-based technologies to separate small proteins/peptides from the large proteins in serum. We used nanoporous silica chips, with a highly periodic nanostructure and uniform pore size distribution, to isolate LMW proteins and peptides from the serum of nude mice with MDA-MB-231 human breast cancer lung metastasis. By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and biostatistical analysis, we were able to identify protein signatures unique to different stages of cancer development. The approach and results reported in this study possess a significant potential for the discovery of proteomic biomarkers that may significantly enhance personalized medicine targeted at metastatic breast cancer.

Properties and Applications of Electrically Small Folded Ellipsoidal Helix Antenna

A comprehensive analysis of the radiation properties of an electrically small folded ellipsoidal helix antenna (EHA) is presented, showing its ability to self-resonate and impedance match without external components. Three antennas with different sizes and geometries have been designed to work at the 2.4-GHz ISM band and are realized using a selective laser sintering (SLS)-based fabrication process. The benefits of using this antenna for various size-restricted applications such as medical implants are also described.

Electrically small folded ellipsoidal helix antenna for medical implant applications

The design and fabrication of electrically small folded ellipsoidal helix antennas is presented for medical implant applications. With ellipsoidal aspect ratio as an additional variable, such antennas have improved radiation resistance tunability over spherical helix antennas while still providing high bandwidth (low Q) and radiation efficiency with small values of ka. A novel 3-D antenna fabrication procedure based on selective laser sintering (SLS) is utilized to rapidly tape-out the ellipsoidal helix antennas on medical implant packages.

All-epitaxial mode-confined vertical-cavity surface-emitting laser

A type of AlGaAs∕GaAs-based vertical-cavity surface-emitting laser is demonstrated that creates a strongly-confined optical mode in an all-epitaxial heterostructure. The mode-confining region in this monolithic device is due to a lithographically defined intracavity phase-shifting layer. Analysis shows that the optical loss in the device can be less than for oxide-confinement.

A zero power harmonic transponder sensor for ubiquitous wireless μL liquid-volume monitoring

Autonomous liquid-volume monitoring is crucial in ubiquitous healthcare. However, conventional approach is based on either human visual observation or expensive detectors, which are costly for future pervasive monitoring. Here we introduce a novel approach based on passive harmonic transponder antenna sensor and frequency hopping spread spectrum (FHSS) pattern analysis, to provide a very low cost wireless μL-resolution liquid-volume monitoring without battery or digital circuits. In our conceptual demonstration, the harmonic transponder comprises of a passive nonlinear frequency multiplier connected to a metamaterial-inspired 3-D antenna designed to be highly sensitive to the liquid-volume within a confined region. The transponder first receives some FHSS signal from an interrogator, then converts such signal to its harmonic band and re-radiates through the antenna sensor. The harmonic signal is picked up by a sniffer receiver and decoded through pattern analysis of the high dimensional FHSS signal strength data. A robust, zero power, absolute accuracy wireless liquid-volume monitoring is realized in the presence of strong direct coupling, background scatters, distance variance as well as near-field human-body interference. The concepts of passive harmonic transponder sensor, metamaterial-inspired antenna sensor, and FHSS pattern analysis based sensor decoding may help establishing cost-effective, energy-efficient and intelligent wireless pervasive healthcare monitoring platforms.

RFID Tag Helix Antenna Sensors for Wireless Drug Dosage Monitoring

Miniaturized helix antennas are integrated with drug reservoirs to function as RFID wireless tag sensors for real-time drug dosage monitoring. The general design procedure of this type of biomedical antenna sensors is proposed based on electromagnetic theory and finite element simulation. A cost effective fabrication process is utilized to encapsulate the antenna sensor within a biocompatible package layer using PDMS material, and at the same time form a drug storage or drug delivery unit inside the sensor. The in vitro experiment on two prototypes of antenna sensor-drug reservoir assembly have shown the ability to monitor the drug dosage by tracking antenna resonant frequency shift from 2.4-2.5-GHz ISM band with realized sensitivity of 1.27 μ l/MHz for transdermal drug delivery monitoring and 2.76- μ l/MHz sensitivity for implanted drug delivery monitoring.

Chemical-sensitive graphene modulator with a memory effect for internet-of-things applications

Modern internet of things (IoTs) and ubiquitous sensor networks could potentially take advantage of chemically sensitive nanomaterials and nanostructures. However, their heterogeneous integration with other electronic modules on a networked sensor node, such as silicon-based modulators and memories, is inherently challenging because of compatibility and integration issues. Here we report a novel paradigm for sensing modulators: a graphene field-effect transistor device that directly modulates a radio frequency (RF) electrical carrier signal when exposed to chemical agents, with a memory effect in its electrochemical history. We demonstrated the concept and implementation of this graphene-based sensing modulator through a frequency-modulation (FM) experiment conducted in a modulation cycle consisting of alternating phases of air exposure and ethanol or water treatment. In addition, we observed an analog memory effect in terms of the charge neutrality point of the graphene, V cnp, which strongly influences the FM results, and developed a calibration method using electrochemical gate-voltage pulse sequences. This graphene-based multifunctional device shows great potential for use in a simple, low-cost, and ultracompact nanomaterial-based nodal architecture to enable continuous, real-time event-based monitoring in pervasive healthcare IoTs, ubiquitous security systems, and other chemical/molecular/gas monitoring applications.

Distributed Amplifiers Based on Spindt-Type Field-Emission Nanotriodes

In this paper, we discuss and analyze the design of a high-frequency, broadband distributed amplifier (DA) based on a 2-D array of field-emission nanotriodes (FENT) consisting of self-aligned gate around a nanomaterial field emitter. We propose here a physics-based device model to characterize dc properties of individual FENTs and a transmission-line circuit for evaluating and optimizing relevant ac properties, including power gain and impedance matching. Our discussion starts from the FENT arrays dc characteristics and covers its radio frequency and microwave properties, considering effects of array density, geometry, FENT dimensions, and nanoemitter work function, in order to maximize power gain and bandwidth for high-frequency applications (30-100 GHz). Finally, we consider the practical design of a transmitter front end for wireless systems, combining the FENT-array DA with a tapered open-ended waveguide antenna, significantly improving matching and power radiation efficiency. Our results are of interest for imaging, sensing, satellite communications, defense, and security at 94 GHz.

Toward transparent and self-activated graphene harmonic transponder sensors

We propose the concept and design of a transparent, flexible, and self-powered wireless sensor comprising a graphene-based sensor/frequency-modulator circuitry and a graphene antenna. In this all-graphene device, the multilayered-graphene antenna receives the fundamental tone at C band and retransmits the frequency-modulated sensed signal (harmonic tone) at X band. The frequency orthogonality between the received/re-transmitted signals may enable high-performance sensing in severe interference/clutter background. Here, a fully passive, quad-ring frequency multiplier is proposed using graphene field-effect transistors, of which the unique ambipolar charge transports render a frequency doubling effect with conversion gain being chemically sensitive to exposed gas/molecular/chemical/infectious agents. This transparent, light-weight, and self-powered system may potentially benefit a number of wireless sensing and diagnosis applications, particularly for smart contact lenses/glasses and microscope slides that ...

Frequency hopped wireless passive sensing system with harmonic transponder antenna sensor

This paper presents a passive wireless sensing paradigm based on the harmonic transponder comprising an antenna covered with a metamaterial-inspired helical structure, which is sensitive to the liquid-level within. An interrogator transmits frequency hopped UHF RFID signals to the transponder, and a sniffer detects the harmonic signal from the transponder and decodes its RSSI array. A μL-resolution absolute accuracy sensing is demonstrated to support the low-cost ubiquitous liquid monitoring.