Biological systems are great at producing large-scale structures from small beginnings: Theoretically a seed could be programmed to grow into a house. ‘Synthetic Biology’, a fast emerging field is already constructing the first of such ‘bio-bricks’.
The number of bacterial cells in your body at this very moment is equivalent to the total population of your own cells. For the most part they are beneficial, preventing infection, aiding digestion, and perhaps even producing useful chemicals. These commensals, as they are called, have evolved with humans in a strongly symbiotic relationship. Clearly, our body is already conditioned to hold a vast army of prokaryotes to do its bidding. How can synthetic biology harness this potential?
Imagine a time in the not-too distant future. Elliott wakes up in the morning to get ready for work. After taking a shower, he examines his clean, clear face in the mirror, deciding that he can probably wait another month before re-applying the bio-spray that keeps his skin pores clean and renders shaving unnecessary. The spray contains skin surface bacteria engineered to eat dirt, oil, and dead skin, as well as dissolve the keratin in facial hair, while keeping the skin intact. They also prevent colonisation by foreign bacteria that can cause infection of pores in skin, preventing acne. He looks at his old toothbrush in the medicine cabinet, and decides to throw it away. Ever since the dentist gave him the oral wash earlier in the year, he has had no use for it. The wash contained a population of bacterial cells programmed to vigorobreak down any stains or food residue, and dissolve plaque buildup. They also created a special biofilm which prevents other bacteria from colonising, eliminating halitosis and gingivitis. Elliott decided to change his breath scent, and picked up a small pen light which he set to yellow and flashed in his mouth. A few minutes later he checked his breath. Faintly sweet and citrusy, very pleasant. The bacteria had been programmed to produce different aromatic compounds.The type Elliott had washed with gave him seven popular scents to choose from.
Elliott now wanted his breakfast. He had a bowl of cereal and milk, along with a spicy southwest omelette and some sausages. He used to be wary of many foods, as he was prone to frequent indigestion, especially from spicy foods or dairy products. But since his visit to the dietician earlier this year, those problems no longer bother him. After analysing his symptoms, the doctor selected a digestive commensal from the Biobricks 3000 catalog which had been programmed for his needs. Now lactose and the irritating chemicals in most spicy foods were broken down with ease in his stomach, before they could cause any distress. An added benefit was that he no longer had to worry about food poisoning. The new commensals specifically targeted and killed any pathogens from a long list of possible food contaminants, and could even neutralize the toxins these bacteria produced. Elliott relished his new state of permanent gastrointestinal bliss.