David Wagner

Highly flexible and biocompatible interposer for medical applications

The focus of this work was the development of additive metal deposition techniques on Polydimethylsiloxane based foils. The metallic films provide electrical interconnection to commercial available surface-mount devices. Therefor two maskless techniques were investigated. First was Aerosol Jet® deposition using an Optomec 3D printer and second was a laser structured thin film, which was deposited with physical vapor deposition (PVD). In addition the contacting between the SMDs and the interposer with an adhesive and a reactive multi-layer foil were investigated. Finally demonstrators which showed the principal functionality were built. For this purpose a simple circuit, composed of battery powered LEDs and a PIC® microcontroller, was developed. The circuit also includes a simple sensor logic which activates the LEDs by touching a comb structure.

A Newly Developed mm-Wave Sensor for Detecting Plaques of Arterial Vessels

Background Microcalcifications within the fibrous cap of the arteriosclerotic plaques lead to the accrual of plaque‐destabilizing mechanical stress. New techniques for plaque screening with small detectors and the ability to differentiate between the smooth and hard elements of plaque formation are necessary. Method Vascular plaque formations are characterized as calcium phosphate containing structures organized as hydroxylapatite resembling the mineral whitlockite. In transmission and reflexion studies with a simple millimeter wave (mm‐wave)‐demonstrator, we found that there is a narrow window for plaque detection in arterial vessels because of the tissue water content, the differentiation to fatty tissue, and the dielectric property of air or water, respectively. Result The new sensor is based on a sensing oscillator working around 27 GHz. The open‐stub capacitance determines the operating frequency of the sensor oscillator. The capacitance depends on the dielectric properties of the surrounding material. The sensor components were completely built up in surface mount technique. Conclusion Completed with a catheter, the sensor based on microwave technology appears as a robust tool ready for further clinical use.

Smart sensor integration in minimally invasive surgery tools

The paper deals with the technique of a hot bar technology for joining conductor lines of flexible interposers directly with copper wires inside of a catheter wall. The copper wires were integrated during the extrusion process inside of the catheter wall. The main part of this paper is concentrating on the evaluation process of such a joining technique. There were used different solder materials. With the help of a design of experiments the process was planned. The final goal is a repeatable process for such a joining method and the integration of a flexible interposer directly inside of a connectable catheter wall.

Application of microwave sensor technology in cardiovascular disease for plaque detection

Abstract Arteriosclerosis and associated cardiovascular disease remains the leading cause of mortality. Improved methods for vascular plaque detection allow early diagnose and better therapeutic options. Present diagnostic tools require intense technical expenditure and diminish value of modern screening methods. Our group developed an microwave sensor for on-site detection of plaque formation in arterial vessels. The sensor is an oscillator working around 27 GHz which is coupled to a microstrip stub line. The final flexible polyimid interposer has a length of 38 cm, a width of 1.2 mm and a thickness of 200 μm. Because of its minimal size the interposer completed a catheter with a diameter of 8F ready for further clinical use in cardiology and heart surgery.

Packaging of a BiCMOS Sensor on a catheter tip for the characterisation of atherosclerotic plaque

The paper deals with a new technique for deviation of atherosclerotic plaque. There are two plaque types: The yellow and white plaque. The white plaque is hard, fibrous and dimensionally stable. The yellow plaque is soft with high-cholesterol ratio and dimensionally instable. Every hit with a medical tool can generate a critical medical case, because the plaque can be rapture and the plaque particles could cause in a stroke. A catheter with a BiCMOS microwave sensor was developed in the latest research. For a stable function and a high reliability a suitable electronic packaging has to be fulfill. The development starting with the sensor design up to a complete electronic packaging which allows a measurement in different liquids and tissues is discussed in this paper.

Evaluation of endourological tools to improve the diagnosis and therapy of ureteral tumors – from model development to clinical application

Abstract Adequate diagnosis of upper urinary tract (UUT) tumors is essential for successful local treatment. Organsparing approaches are technically difficult and require consistent further development. Appropriate models for investigating new diagnostic and therapeutic methods are not yet available. This study demonstrates the incorporation of a fresh sample model into five different test levels (I-V) for improving the diagnosis and therapy of ureteral tumors. In these test levels, new diagnostic and ablation techniques are evaluated for feasibility, application safety, efficacy and accuracy. An assessment of their suitability for broad preclinical and clinical application also took economic aspects into account.

Challenges to the electronics packaging technologies for the volume integration of components in medical tools and instruments

The electronics packaging in microsystems technology for medical applications includes various tasks. The interdisciplinary approach is the most important basis for the success of a product. For the reliable operation of medical microsystems different factors must be considered. For example the functionalization of a catheter depends on different influence factors. The form factor takes the most important role. For a miniaturized and functional catheter tip, the diameter depends on the medical application. Other factors like the shape, reliability and also the cost must be considered. The paper shows the whole technology carrier of a medical product in relation to the field of electronics packaging. With the help of two examples the requirements for future products will be shown.

Electronics packaging technologies for the volume integration in components for medical tools and instruments

The electronics packaging in microsystems technology for medical applications includes various tasks. The interdisciplinary approach is the most important basis for the success of a product. For the reliable operation of medical microsystems different factors must be considered. The functionalization of a catheter depends on different influence factors. The form factor takes the most important role. For a miniaturized and functional catheter tip, the diameter depends on the medical application. Other factors like the shape, reliability and also the cost must be considered. The paper shows the whole technology carrier of a medical product in relation to the field of electronics packaging.