Performing Department
(N/A)
Non Technical Summary
There is a health care gap between ruaral and urban communities. Rural communities have a greater percentage of high cholesterol, high blood pressure, arthritis, multiple chronic conditions, diabetes, heart disease, cancer and stroke. There are fewer doctors, clinics, hospitals and specialists to serve the rural community and the distances to reach specialists can be daunting. Due to lower income in rural areas, higher cost diagnostic instruments are not available for many communities. As a result, rural Americans are slower to visit a doctor, less likely to see specialists or to schedule follow ups. The end result is disease diagnosis in rural America occurs at a later stage; whereas cancer may be diagnosed in an early stage in the city, the diagnosis is more likely to be Stage 3 or Stage 4in rural America. It is critical to create a rapid, inexpensive diagnostic test that closes the health care gap and provides rural Americans with an opportunity for early disease diagnosis. Such a diagnostic tool would not only improve quality of life, but would help ease health care costs by not only providing an inexpensive diagnostic tool but by catching diseases in the early stage when more treatment options are available.This program will make use of the high sensitivity of Surface-enhanced Raman Spectroscopy (SERS), the unique selectivity of monoclonal antibodies, and the detection of many new disease biomarkers that are readily assessed in blood, saliva or urine to create a series of diagnostic tests for different diseases. By changing the antibodies and maintaining the SERS infrastructure, different diseases can be analyzed using one simple instrument that will cost ~$5000. Using 3-5 different biomarkers for a specific disease and measuring them in one SERS measurement will improve the measurement accuracy, decreasing false positives and false negatives. The measurement can be performed in 10 minutes or less and would need a sample swab using a Q-tip like device that contains the antibodies to bind the biomarkers of interest. The swab is placed into the instrument sampling compartment containing the SERS identifying tags, the end user hits start and the instrument determineswhether the markers for the disease of interest are present. A non specialist can perform the analysis in any setting. High volume diagnostics can be achieved in local gathering places. For example, a prostate cancer screening could be held in the parking lot of a local supermarket. By moving to different locations, not only can many rural Americans be screened and treated, closing the health care gap, but a thorough epidemiological mapping can be performed to allow healthcare organizations to predict and prepare for potential future health issues.
Animal Health Component
50%
Research Effort Categories
Basic
0%
Applied
50%
Developmental
50%
Goals / Objectives
The program objective is to develop a one-step analysis for a variety of diseases that can be routinely performed in a field, clinic or office setting. The goal is to create a series of rapid test sensors that can be used in rural locations economically and rapidly detect a variety of diseases, helping to alleviate to medical disparity for rural communities. This sensor will be based on novel magnetic SERS sandwich-type designs with appropriate antibodies to detect multiple biomarkers of disease. The Phase I objective is to demonstrate the technical feasibility of the magnetic SERS sensors to simultaneously detect two prostate cancer biomarkers at concentrations of relevance and with no false negatives and minimal to no false positives. The following technical questions must be answered:Can SERS detect biomarkers at sensitivity limits comparable to current analytical laboratory procedures?Can SERS produce a false positive/negative rate that matches current methods?Can SERS provide results on-site and quickly to enable results to be provided to patient within 10-15 minutes from collection of the patient biofluid?Can the protocol/instrumentation be simplified so a non specialist can snap the applicator into alignment for data collection and get an automated result with no additional steps?The Phase I program will develop a set of SERS sandwich assays consisting of a magnetic SERS bead with surface antibodies for biomarker capture and an antibody with SERS nanotag to create the sandwich assay. In the Phase I program, the biomarkers glutamate oxaloacetate transaminase 1 (GOT1) and kallikrein 1 related peptidase will be evaluated. The Phase I program will answer relevant scientific questions and will have a clearly defined milestone of unique identification of the above compounds, definition of reproducibility, detection limits and a preliminary interference analysis by which to grade the Phase I results. The Phase II program will then extend the Phase I results by incorporating cancer antigen 3, kallikrein 5 related peptidase, and the small molecules aconitic acid and sarcosine into the Phase I sensor to create a sensor array for prostate cancer detection in urine. Analytical figures of merit will be produced and ROC curve analyses for the sensor on a variety of spiked synthetic urine samples will be performed. In addition, a second SERS applicator optimized for pancreatic cancer detection in blood samples will be developed. A high throughput sampling accessory will be designed and fabricated. A portable spectrograph with appropriate automation software for rapid identification and presentation to the end user will be developed. The full system will be tested using biological matrices and will end with blind testing and ROC curve development.
Project Methods
The Phase I program will create 2 SERS sandwich assays, one to detect glutamate oxaloacetate transaminase1 (GOT1) and the other to detect kallikrein related peptidase. Each is a biomarker for prostate cancer. The magnetic nanocores will be fabricated in-house following literature protocals to create uniform spheroidal cores. Modifications to the protocol will be performed to improve the size uniformity, if needed. The nanospheres will be coated with SiO2following literature, but will also be evaluated with a titanium coating alternative as well, due to EIC observations of a SiO2 lattice mismatch with silver and gold and instability/delamination in harsh environments, such as urine. Titanium has proven to be superior. Silver or gold overcoating will be performed according to literature, creating the SERS anchor on which to attach the desired antibody. These anchors will be evaluated for durability in different temperatures, pH ranges and salinities.Once satisfied with the anchor the antibodies for the respective biomarkers will be integrated. Both streptavidin complexation and direct binding will be evaluated.The second half of the sandwich assay will be create using colloids as the SERS anchor. To this anchor, a unique SERS nanotag is added for each biomarker (4-mercaptobenzoic acid for GOT1 and 4-aminobenzoic acid for kallikrein related peptidase). These nanotags are exceedingly strong SERS scatterers, allowing potential single molecule detection. Once the nanotags are bound and any excess weakly bound tags removed through washing, the antibodies are attached to the nanotags. Evaluation of the prospective sandwich assays will be performed by verifying no signal observed on the magnetic nanoparticles when the biomarker of interest is not present and the presence of a strong SERS signal corresponding to the nanotag when the biomarker is present and the sandwich is created. Interference analysis of other anticipated matrix components and the effect of environmental variations on signal strength will be fully evaluated. Signal reproducibility, selectivity, and sensitivity will all be evaluated and reported.A key component of this program is a combined sample collector and SERS analyzer. The collector will be a modified version of a cotton tip applicator. The polyethylene handle would contain a SERS sensor at the distal end, under the wound cotton that adsorbs the analyte. Cellulose is a poor Raman/SERS scatterer and would have minimal impact on signal collection. Custom design of different SERS sensors would allow multiple market penetrations using the same applicator package. For example, one applicator could have embedded SERS sensors that detect glutamate oxaloacetate transaminase 1, prostate cancer antigen 3, several kallikrein related peptidases and aconitic acid simultaneously. The applicator would be stabilized in a vial that locks precisely into the Raman analyzer. In the vial, there is a premeasured volume of solution containing the appropriate antibodies with SERS tag to complete thesandwich assay. Each SERS tag would be unique and observed at a frequency resolved from the other tags. The end user would add a small volume of biofluid to the vial and hit the start button. The instrument would then perform the analysis after the appropriate mix time, quantify the data and return a result to the end user. The entire procedure could be performed within 10 minutes of the patient providing a biological sample,expediting results. Other applicator packages could detect ovarian, pancreatic, cervix, or breast cancers, as well as various viral infections or early onset dementia. Each different test could still be optimized with the same SERS tags, simplifying analysis. Raman instrumentation can cost as little as 5K, is very rugged (a current EIC instrument has spent parts of the last 13 years being transported to NC for field work), is compact and can be easily automated to provide results to non specialists. Using the same SERS nanotags for different applicator packages allows for a potential filter-based Raman system, reducing spectrometer cost down to <1K.The applicator design will consist of a ¼" polyethylene rod cut to a 3.5" length witha 1/8" dia. hole drilled 3/16" deep into one end. A 1/8" dia. x ¾" long magnetis mounted into the hole. The applicator will be immersed in a solution containing the desired SERS magnetic nanoparticles, fabricated separately. Just prior to removal, a mild sonication will be performed to remove poorly bound nanoparticles. The cotton overlayer will be added and bound only to the polyethylene section. In urine, the applicator design is mainly functional as an alignment and collection tool; the sheath does not need to be added. In blood, the overlayer can be used as a filter to prevent adsorption of membrane and large particulates from the blood samples. The applicatorcanbe used as a collector and analyzer during saliva analysis. For the Phase I program, a biocompatible, double sided surgical tape will be used with binding material optimization reserved for the Phase II program. At a distance of 1.5" down from the top of the applicator is a cover. After swabbing, this cap screws onto the analysis cell to align the SERS probes precisely and reproducibly into the laser focal volume. The cell can be generic and integrated into a commercial or custom Raman instrument. After the swab is secured, the end user would hit the start button and the instrument would automatically collect the SERS spectrum, compare to the reference library and report the presence/absence of the disease under investigation. Production and evaluation of this applicator for the two previously described biomarkers will be performed in this program.Based on the results obtained, an optimal design for the instrument, applicator, assays will be determined and presented for Phase II fabrication. In addition, an optimal protocol will have been determined and will be used to create the software necessary to allow accurate usage by a non specialist.