UCLA researchers in the Department of Dentistry have developed a method of using improved polymer-based biosensors to detect the presence of nucleic acids, proteins, and other analytes in bodily fluids such as saliva in order to diagnose diseases such as oral cancer.
BACKGROUND:
Highly sensitive and robust detection methodologies, specifically those for the detection of biomolecules indicative of cancer, can improve point-of-care devices and other diagnostic technologies. For example, polymer-based biosensors have been extensively developed. Conducting polymers such as polypyrrole have been used on biosensors to detect analytes such as RNA, proteins, and biomarkers. However, existing polymer-based biosensors face certain limitations. Specifically, probes that bind to biomolecules of interest are often mixed with the monomeric solution of the conducting polymer prior to electro-polymerization and formation of the polymer film on the biosensor surface. This results in low probe immobilization efficiency on the biosensor surface. A universal platform for immobilizing different types of probes with high surface density and high binding activity is desirable.
INNOVATION:
UCLA researchers in the Department of Dentistry have developed a method of using improved polymer-based biosensors to detect the presence of analytes in bodily fluids such as saliva in order to diagnose diseases such as oral cancer. The polymer-based biosensor includes a conducting polymer such as polypyrrole and nanoparticles with a capture moiety such as an oligonucleotide or antibody. The nanoparticles are added to monomeric units of the conducting polymer, and electro-polymerization is used to form a polymer film on the surface of the biosensor.
When the biosensor is contacted with saliva, a probe such as an antibody that binds an analyte of interest in the saliva is immobilized on the biosensor surface through a designed linkage between the probe and the nanoparticle. The analyte may be mRNA, proteins, or other biomarkers that are overexpressed in oral cancer cells. By applying voltage to the biosensor, the amount of analyte can be quantified based on the current intensity generated on the biosensor.
An advantage of the current biosensor over most existing biosensors is that the probe is not introduced into the monomer solution prior to polymerization. This allows for controllable, high-surface density of the immobilized probe on the biosensor. The polymer-based biosensors of the present invention provide the additional advantage of a universal, pre-optimized platform for the immobilization of different types of probes, such that changing from one type of probe to another does not require changing the parameters of immobilization.
The presence of analytes such as isolated extracellular mRNA in saliva may also be detected and quantified by other methods, including by microarray assay and quantitative PCR. In response to detecting the overexpression of an analyte that is indicative of oral cancer or other cancers, including oropharyngeal squamous cell carcinoma, a treatment plan may be formulated.
POTENTIAL APPLICATIONS:
• Detection of oral and other types of cancer
• Point-of-care devices and other diagnostic technologies
ADVANTAGES:
• Controllable, high-surface density of the immobilized probe on the biosensor
• Universal, pre-optimized platform for the immobilization of different types of probes