Xitian Pi

The study of a remote-controlled gastrointestinal drug delivery and sampling system.

A micromachined capsule based on microelectromechanical systems (MEMS) technology is introduced in this paper. It is an effective tool for diagnosing and treating gastrointestinal diseases. The microcapsule can carry out real-time drug release and the gastrointestinal fluid sampling in the gastrointestinal tract. According to the structural and metabolic characters of the gastrointestinal tract, the configuration of the microcapsule was designed as a cylinder. This nondigestible oral device can smoothly pass through the gastrointestinal tract for drug delivery and liquid sampling. The working mechanism of the capsule was the mechanic movement mode of a piston, which was regulated through a MEMS calorific element. The action of drug delivery and gastrointestinal fluid sampling in the gastrointestinal tract was performed wirelessly. The remote control device can be connected with a computer through a serial port (RS-232), and it can be used in telemedicine applications. Some experimental research has been carried out to validate the design. The experimental results indicated that the microcapsule can achieve drug delivery and liquid sample reliably.

Advances in the Early Detection of Lung Cancer using Analysis of Volatile Organic Compounds: From Imaging to Sensors

According to the World Health Organization (WHO), 1.37 million people died of lung cancer all around the world in 2008, occupying the first place in all cancer-related deaths. However, this number might be decreased if patients were detected earlier and treated appropriately. Unfortunately, traditional imaging techniques are not sufficiently satisfactory for early detection of lung cancer because of limitations. As one alternative, breath volatile organic compounds (VOCs) may reflect the biochemical status of the body and provide clues to some diseases including lung cancer at early stage. Early detection of lung cancer based on breath analysis is becoming more and more valued because it is non-invasive, sensitive, inexpensive and simple. In this review article, we analyze the limitations of traditional imaging techniques in the early detection of lung cancer, illustrate possible mechanisms of the production of VOCs in cancerous cells, present evidence that supports the detection of such disease using breath analysis, and summarize the advances in the study of E-noses based on gas sensitive sensors. In conclusion, the analysis of breath VOCs is a better choice for the early detection of lung cancer compared to imaging techniques. We recommend a more comprehensive technique that integrates the analysis of VOCs and non-VOCs in breath. In addition, VOCs in urine may also be a trend in research on the early detection of lung cancer.

A Preliminary Study of the Noninvasive Remote Control System for Rat Bio-Robot

A system is described here that can noninvasively control the navigation of freely behaving rat via ultrasonic, epidermal and LED photic stimulators on the back. The system receives commands from a remote host computer to deliver specified electrical stimulations to the hearing, pain and visual senses of the rat respectively. The results demonstrate that the three stimuli work in groups for the rat navigation. We can control the rat to proceed and make right and left turns with great efficiency. This experiment verified that the rat was able to reach a setting destination in the way of cable with the help of a person through the appropriate coordination of the three stimulators. The telemetry video camera mounted on the head of the rat also achieved distant image acquisition and helped to adjust its navigation path over a distance of 300 m. In a word, the non-invasive motion control navigation system is a good, stable and reliable bio-robot.

A smart capsule system of gastric occult blood detection.

Prior research indicated that occult blood screening can be used to detect early gastric cancer. Based on capsule endoscopy and occult blood detection theory, an automatic detection capsule system for gastric occult blood (GOB) was proposed. This paper designed the detecting sensor, image acquisition system and wireless transmitter module respectively based on collaurum immune theory, the image sensor and radio frequency chip. In vitro experiments were conducted to testify the system, and the detecting result image information was acquired by the image acquisition (IMAQ) system and transmitted to the outside of the body through the wireless transmitter module. The receiver module received and displayed the information on the computer, from which doctors could diagnose whether there was occult blood (OB) or not. Therefore, this paper provides a new idea for the screening of early-stage gastric cancer with reliability and simplicity.

An Intelligent Electronic Capsule System for Automated Detection of Gastrointestinal Bleeding

In clinical practice, examination of the hemorrhagic spot (HS) remains difficult. In this paper, we describe a remote controlled capsule (RCC) micro-system with an automated, color-based sensor to identify and localize the HS of the gastrointestinal (GI) tract. In vitro testing of the detecting sensor demonstrated that it was capable of discriminating mimetic intestinal fluid (MIF) with and without the hemoglobin (Hb) when the concentration of Hb in MIF was above 0.05 g/ml. Therefore, this RCC system is able to detect the relatively accurate location of the HS in the GI tract.

Collecting Protein Biomarkers in Breath Using Electret Filters: A Preliminary Method on New Technical Model and Human Study

Biomarkers in exhaled breath are useful for respiratory disease diagnosis in human volunteers. Conventional methods that collect non-volatile biomarkers, however, necessitate an extensive dilution and sanitation processes that lowers collection efficiencies and convenience of use. Electret filter emerged in recent decade to collect virus biomarkers in exhaled breath given its simplicity and effectiveness. To investigate the capability of electret filters to collect protein biomarkers, a model that consists of an atomizer that produces protein aerosol and an electret filter that collects albumin and carcinoembryonic antigen-a typical biomarker in lung cancer development- from the atomizer is developed. A device using electret filter as the collecting medium is designed to collect human albumin from exhaled breath of 6 volunteers. Comparison of the collecting ability between the electret filter method and other 2 reported methods is finally performed based on the amounts of albumin collected from human exhaled breath. In conclusion, a decreasing collection efficiency ranging from 17.6% to 2.3% for atomized albumin aerosol and 42% to 12.5% for atomized carcinoembryonic antigen particles is found; moreover, an optimum volume of sampling human exhaled breath ranging from 100 L to 200 L is also observed; finally, the self-designed collecting device shows a significantly better performance in collecting albumin from human exhaled breath than the exhaled breath condensate method (p<0.05) but is not significantly more effective than reported 3-stage impactor method (p>0.05). In summary, electret filters are potential in collecting non-volatile biomarkers in human exhaled breath not only because it was simpler, cheaper and easier to use than traditional methods but also for its better collecting performance.

Preliminary study of an automatic detection capsule system for gastric occult blood

Based on capsule endoscopy and Occult Blood (OB) detection theory, an automatic detection capsule system for Gastric Occult Blood (GOB) was proposed. This system utilised the non-invasive deglutible capsule to automatically identify the GOB information and transmitted the detection result to the external device which could display the detection result and identify the OB status with a particular algorithm. Subjects or doctors could discriminate whether OB existed by observing the external device. This paper designed the automatic detection capsule of GOB and the detecting sensor based on collaurum immune theory. We did in vitro experiments to testify the system and acquired the detecting result image information. Experimental results indicated that the effective detection concentration range of the OB sensor was 6–1800 μg/ml. With simplicity and reliability, this system provides a new idea for the screening of early stage gastric cancer.

Preliminary study of an intestinal bio-robot system based on nerve stimulation

BackgroundWireless capsule endoscopes for diagnosis and treatment in the gastrointestinal tract face the common problem of active actuation. To tackle this difficulty, a non-invasive intestinal bio-robot system with active actuation based on nerve stimulation was developed.MethodsThis intestinal inspection system utilized a natural organism—the mud eel—to serve as the locomotion mechanism, and it was controlled by a LabVIEW-programmed pulse generator. The exterior control unit was able to actively drive and remotely control the navigation and site-specific anchoring of the organism.ResultsThrough in vitro stimulation experiments, a method of controlling the organism’s forward motion was obtained: when the organism was stimulated at the tail, it moved forward at a relatively fast speed and with high repeatability. The stimulator parameters were as follows: amplitude 1.85 μA, frequency 2 Hz, pulse duration 500 μs.ConclusionsSince this is a preliminary study, considerable work remains to be done. However, the results could provide a solid theoretical basis for further research toward producing a practical intestinal bio-robot for the diagnosis and treatment of the gastrointestinal tract.

On a microfabricated Ti-alloy-based microneedle array for transdermal drug delivery

Transdermal drug delivery is a promising approach that allows controlled release of drug over time while avoiding possible degradation due to the gastrointestinal tract or first-pass liver effect. Of many different methods have been employed in transdermal drug delivery, microneedle is a widely explored MEMS-based device that can conveniently penetrate the skin and thus create micrometer-scale openings for drug absorption. In this paper, we attempt to study a Ti alloy-based microneedle array, particularly its fluidic features, through a series of simulations using ANSYS. The results indicate that, provided the volumetric flow rate is constant, the pressure of inlet decreases when the flow rate of inlet increases; the flow rate of outlet increases with the increase of pressure of inlet when flow rate of inlet is set to constant. In both scenarios, a complete description of liquid flow through microneedle conduit should consider in vivo effects such as the liquid absorption in the epidermis and the mechanic feature.

Simulation of the diaphragm properties of a PZT-based valveless micropump

PZT-based micropump is a broadly studied microactuator that could be potentially used for controlling and delivering tiny amounts of fluids as it has simple structure and no internal moving parts. This paper presents a PZT-based micropump which pump fluid via the motion of diaphragm bonded to the piezoelectric element. The mechanical properties of diaphragm driven by input voltages have been analyzed here with ANSYS. The simulation results indicate that the profile of either displacement or velocity of diaphragm is a parabolic surface, in which the maximal value occurred in the central area of diaphragm, and the minimal value occurred at the boundary. Furthermore, the activities of vibration membrane of micropump would be controlled by the driving voltage and thickness of PZT patch, and the displacement of vibration membrane would increase with either the increment of driving voltage or decrement of PZT thickness. The proposed micropump can be potentially integrated into a transdermal drug delivery system, and the simulation results demonstrate its utility as an efficient tool for PZT-based micropump design.