Lab-on-a-chip may soon be available for the iPhone and iPad

The idea of detecting infectious diseases or diagnosing respiratory diseases using your cell phone is not a far fetched idea. The technology to detect infectious diseases using a lab-on-a-chip in a fast, reliable, and in a cheap way already exists. A study published in the journal of Nature Medicine and other studies that came out on the journal of Lab Chip this month demonstrated how a simple $0.10 polystyrene (plastic) chip can be used to diagnose syphilis and AIDS in the fields of Africa. The technology produced by the authors of this study requires no moving parts, electricity or bulky external instrumentation and is extremely cheap. In brief, each chip can accommodate upto seven blood samples that are loaded onto seven individual channels on the chip. The blood travels through multiple chambers (four detection zones) where the HIV and syphilis antigens (proteins) are bound and immobilized on the surface, mixes with reagents (secondary antibodies) and silver and gold particles mix in the end help to amplify the signal through the reduction of silver. The reduction of silver with gold will emit a signal that does not require amplification as seen with standard enzyme linked assays such as ELISAs. Hence, the authors of this study convincingly showed how the mChips achieve similar sensitivity (detect more true positive

s) and specificity values (less false positives) similar or better to commercial ELISA kits used to detect HIV and syphilis. Also, the whole assay requires less than thirty minutes compared to three hours with standard ELISAS. In the future, mChip can be tailored to diagnose for a myriad of other diseases using this ELISA-like technique. Other wordlwide relevant disease that can be diagnose with this technology include MRSA (Methycillin resistant Streptococcus aereous), influenza viruses, meningitis infections and streptococcal and the nasty rotavirus and noraviruses that cause diarrhea in 50% of children worldwide. There is an exciting suggestion provided by the authors is that a compact reader that can interpret the signals already exists in cell phones. Photodetectors capture photo-signals emitted by the chip are send to LEDs which are relayed to an LCD display (cell phone screen).Only a small peripheral/ module that can attach to the compact readers of a cell phone will have to be designed to connect the polystyrene chip to the cell phone. An iPhone application will have to be developed to measure and interpret the optical density of the results. There are already iPhone applications that can read electrical recordings from neurons and that allows the user to measure beta radiation. iPhone peripherals that are bound to come out the market will help to diagnose the sugar levels for people with diabetes or read ECG signals. Finally, the great news of this study is that the authors provided a basic business plan and suggests different methods for mass producing this cheap technology that can be used in third world countries to easily diagnose STDs. Also, this type of technology is called microfluidics and it is a very marketable and hot field that can produce millions of dollars in revenue for many small companies in the next five years. The technology of these chips will provide the customers to diagnose for a variety of different diseases from biological samples derived from blood, sputum, respiratory secretions and urine samples and the results of the diagnosis will not require a high level of knowledge for interpretation. What is microfluidics and what are the advantages? Lab-on-a-chips employ the principle of enzyme-linked immuno-absorbent assays (ELISA) systems currently employed by research and clinical labs. The principle is very simple. In lamest terms, an unknown amount of antigen is immobilized to a surface (usually polystyrene), and then an antibody is added over the surface for an hour and allowed to bind to the antigen. Unbound excess antibody is washed off with wash buffers several times after which a secondary antibody that is linked an enzyme is overlayed and the reaction is incubated for another hour. In the final step a substance is added that the enzyme can convert to a detectable and quantifiable signal. While a conventional ELISA assay takes about at least three hours to perform by a professional clinical laboratory technician, anyone will be able to uses these devices to perform bio-measurements faster, reliably, more economical and in a matter of approximately less than five minutes at home. Microfluidics is an nano-engineering technique with the goal of producing tiny silicon or glass chips that have thousands tiny passageways and convoluted canals similar to a computer chip but on a bigger scale except that fluid and not electricity flow through the chip. Fluids are drawn and absorbed from different ports (input) and the fluids will travel through the small little canals without the need of electricity but by tension forces produced by fluids. There are many ways to design microfluidics chips and it all depends on the specific need, types of samples to be analyzed and the types of clinical questions that need to be answered. Did you find this article interesting? Will you like to receive more medical technology related news? Please leave a comment or subscribe to my newsletter by clicking the "subscribe" tab located on the top left hand side of my homepage or follow me on Twitter.