SBIR-STTR Award

RPN Research has recently developed a new instrument called the Bioelectric Field Imager (BFI) that allows us to measure the surface potential of the skin without touching it. We have used the BFI to map the lateral electric field surrounding a skin wound in mice and propose here to determine its usefulness for the diagnosis of skin tumors. We have known for 160 years that human skin drives ionic current out of regions where the integrity of the epidermis has been breached (DuBois-Reymond, 1843). This current then passes between the stratum corneum and the epidermis, generating a lateral electric field surrounding the lesion. Regions of intact, healthy skin do not exhibit such lateral electric fields so the presence of such fields is a strong indicator of a wound or lesion. If lesions such as melanoma or basal cell carcinoma reduce the resistance across the epidermis, we would expect to detect lateral electric fields near these tumors. We have used a mouse model system in which we induce a melanoma to develop by injecting B16 murine melanoma cells beneath the skin. We present preliminary measurements of lateral electric fields associated with these melanomas. Fields of 600 mV/mm and greater are associated with these melanomas as early as 1 day after we inject the melanoma cells beneath the skin. Much more needs to be done to establish the reliability of this approach. We propose to conduct a histological study to correlate the measured electric field strength with melanoma size and will establish the reliability of this technique for the diagnosis of skin lesions. We will also conduct clinical investigations on humans to determine if the BFI can distinguish between benign and malignant skin lesions. If so, the BFI could improve human health by early detection of skin disease and may provide a routine diagnostic device that could reduce the number of biopsies necessary. There are very few medical devices to aid dermatologists and other physicians in the diagnosis of skin disease at the present time. They must rely on past experience and the results of biopsies performed on each patient (Farmer and Hood, 2000). The BFI can provide additional information about the suspected lesion that may prove very informative in making the diagnosis. The three most common forms of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma all cause disruptions in the epidermis and would be expected to generate local electric fields that could be detected by the BFI.

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RPN Research has developed a new medical device, the Bioelectric Field Imager (BFI) which can measure the electric field in human skin non-invasively. The hand-held BFI scans a vibrating sensor over the skin without making contact with it and plots the surface potential distribution over a 1 cm distance in about 1 minute. Using a table-mounted version of this new imager in Phase I of this project, we have revealed for the first time that malignant melanomas in mice generate an electric field that can be easily detected by the BFI. These studies found that the electric field can be detected as early as one day after injection of the melanoma cells and the electric field strength is proportional to both the size and growth rate of the melanoma. We have also completed a Phase I Clinical Trial using the hand-held BFI to measure the electric field in both benign and malignant human skin lesions and have found that malignant basal and squamous cell carcinomas generate large electric fields in human skin as well. In our Clinical Trial we found that the hand-held BFI detected an electric field averaging 696 mV/mm at the borders of three of the four malignant lesions in the study (3 basal cell carcinomas and 1 squamous cell carcinoma). This 75% reliability rate in our first human clinical trial is encouraging. In addition, the average electric field measured near benign lesions (223 mV/mm) was only one-third the size of those near malignant lesions, making it very easy to distinguish between the two. In 9 out of 13 benign lesions (70%) we detected a very small electric field and correctly predicted in a blinded study they were not malignant. During this Phase II SBIR we will refine the design of the hand-held BFI to make it more versatile and reliable for human use my making it lighter, wireless and compatible with a wider variety of lesion shapes. We will complete a Phase II Clinical Trial with at least 300 patients to establish the reliability of this new instrument for rapidly distinguishing malignant from benign skin lesions. We will also compare the electric field near melanomas as measured with the BFI to that measured using conventional microelectrodes to both serve as a confirmation of the accuracy of the BFI and to further demonstrate its advantages over the direct contact measurement approach. If the handheld BFI is able to reliably detect malignant skin lesions, it will improve the quality of life for tens of thousands of dermatology patients in the United States alone