It is difficult to imagine how a discovery in physics could reverberate around the world in the same way that Dolly the cloned sheep has in recent weeks. As biologists clone sheep and monkeys – albeit with only one event in noisy backgrounds of several hundred failed attempts – physicists are still trying to ‘clone’ the wavefunctions of single atoms, and then only in special circumstances. Yet as medical and biological research garners larger amounts of the public funds available for science, physicists with the requisite expertise could do worse than follow the old adage: “If you can’t beat them, join them”.
Physicists have developed a range of techniques now routinely used in medical diagnosis and, to a lesser extent, in treatment and therapy. However, there are also numerous opportunities for physicists to contribute to the most basic research in the life sciences. They would be in good company. Erwin Schrödinger was one of the first to stray into this field, most notably with the publication of What is Life? in 1944. Other physicists have left the fold completely and become biologists: Francis Crick of double-helix fame is one who springs to mind. Instrumentation will, inevitably, be the area where physicists have most to contribute. The enormous worldwide effort currently under way to sequence the human genome relies heavily on automated techniques, many based on physical processes such as fluorescence. Nuclear magnetic resonance is widely used to study the behaviour of proteins, while the manipulation of biological samples with scanning force microscopes and laser tweezers is becoming more widespread. In the US, neuroscience departments in universities are recruiting physicists to investigate how the brain works – optical imaging of voltage-sensitive dyes is a key tool in this research. Lucent Technologies is also doing similar work to figure out new directions in computing. Elsewhere, single-photon emission computed tomography (SPECT) is joining better known techniques, such as PET and MRI, to study drug addiction and various brain disorders.
An ongoing challenge in biology is to understand protein folding, in particular how the sequence of amino acids in the protein determines its final shape and function. Some have called this problem the ‘biological equivalent of the big bang’. Physicists have steadily been moving into this area for some time, bringing new theoretical and experimental tools to bear on this most basic, yet most puzzling, of processes. However, it would be naive to think that physicists could solve this or any other biological problem on their own – interdisciplinary collaboration must be the order of the day. Indeed, biology has a lot to teach the physical sciences, and some enterprising physical chemists are already using DNA-based techniques to self-assemble metal nanoparticles. Their long-term goal is to make nanoparticles with useful optical and electronic properties.
Moving into biology will also involve a change of mind set for physicists: notions of reproducibility and predictability will have to be rethought, and guiding principles like symmetry and associated conservation laws will be less powerful than in the physical world. As for a discovery to match cloning, unless some determined general relativist manages to build a time machine and return to the present with Einstein, 100 years from now the world will probably be celebrating the centenary of Dolly rather than the bicentenary of the electron.
