Rapid and simple clinical assays using nanoscale phage-based detectors and linear dichroism spectroscopy.

Much of the work carried out today in clinical medicine involves measuring chemicals in a variety of samples. For example, measurement of hormone levels is an important part of monitoring a number of clinical conditions including infertility. In addition, infection control (particularly for problem pathogens such as MRSA and C. Difficile) involves constant monitoring of patients before, during and after visit to hospital. Much of this monitoring is carried out by skilled scientist in laboratories in hospitals, using complex tests using specially developed antibody reagents. This is not ideally suited to situations where a rapid response may be required. For instance when a GP requires a test for a certain hormone to be carried out, a sample has to be taken by the GP, sent to the hospital, where the test is done (typically taking a number of hours) and results sent to the GP. This leads to delays in diagnosis which lead to and increase the likelihood for a negative outcome for the patient. Our work aims to greatly simplify and speed up the assays currently used in clinical medicine. We plan to use a specific type of virus that infects bacteria called a phage. The phage is a highly complex structure that is very long and thing. The advantage of the phage is that it can be genetically altered to bind to the antibody reagents used in current assays. We have also shown that these phage can be detected by the way in which it absorbs a certain type of polarised light. This effect is only observed when phage are aligned in solution. (Much like the way spaghetti lines up when it is stirred in a saucepan). We have shown that if something else sticks to the phage then the phage no longer aligns and we cannot detect it anymore. This means that if our phage-antibody particles bind to a germ or hormone our system will detect its presence.So why will this help simplify assays? Our assay will require only the simple addition of the phage-antibody to the sample. This is compared to the existing system that requires at least 3 reagents to be added requiring a specialist scientist. Then in our system it is a simple task to read the result using a simple instrument. The complete assay procedure would take <5 minutes which is extremely rapid compared to the current systems which can take hours.This makes it possible for the assay system to be used in GP surgeries or directly on the clinical ward. Finally the system uses antibodies that have already been developed for the existing assays meaning that all currently available tests can be used immediately with this new detection system.Taken together the phage-antibody detection system will help improve diagnosis and control of disease for a wide range of patients.