Bio computers

What are biocomputers?

• Biological computers use biologically derived molecules such as DNA and/or proteins to perform digital or real computations. 
• The development of biocomputers has been made possible by the expanding new science of nanobiotechnology.
• With this the brain cultures grown in the lab are coupled to real-world sensors and input/output devices. 
• The scientists expect the technology to harness the processing power of the brain and understand the biological basis of human cognition, learning, and various neurological disorders.

Organoids to biocomputers-

• In a quest to develop systems that are more relevant to humans, scientists are building 3D cultures of brain tissue in the lab, also called brain organoids. 
• These “mini-brains” (with a size of up to 4 mm) are built using human stem cells and capture many structural and functional features of a developing human brain. 
• Researchers are now using them to study human brain development and test drugs to see how they respond.
• However, the human brain also requires various sensory inputs (touch, smell, vision, etc.) to develop into the complex organ it is, and brain organoids developed in the lab aren’t sophisticated enough. 

• The organoids currently also don’t have blood circulation, which limits how they can grow.

• Recently, scientists transplanted these human brain organoid cultures into rat brains, where they formed connections with the rat brain, which in turn provided circulating blood. 
• Since the organoids had been transplanted to the visual system, when the scientists showed the experimental rats a light flash, the human neurons were activated, too, indicating that the human brain organoids were also functionally active.
• Scientists have touted such a system as a way to study brain diseases in a human context. 
• However, human brain organoids are still nested in the rat-brain microenvironment, including the non-neuronal cells. 
• The effects of drugs in this model will also have to be interpreted through various behavioural tests in rats, which could be insufficiently representative.  

What is the new ‘bio-computer’?

• The JHU researchers’ scheme will combine brain organoids with modern computing methods to create “bio-computers”. 
• They have announced plans to couple the organoids with machine learning by growing the organoids inside flexible structures affixed with multiple electrodes (similar to the ones used to take EEG readings from the brain).
• These structures will be able to record the firing patterns of the neurons and also deliver electrical stimuli, to mimic sensory stimuli. 
• The response pattern of the neurons and their effect on human behaviour or biology will then be analysed by machine-learning techniques.
• Recently, scientists were able to grow human neurons on top of a microelectrode array that could both record and stimulate these neurons. 
• Using positive or negative electric feedback from the sensors, they were able to train the neurons to generate a pattern of electrical activity that would be generated if the neurons were playing table tennis.

Benefits of bio-computers-

• While human brains are slower than computers at, say, simple arithmetic, they outshine machines at processing complex information.
• Brain organoids can also be developed using stem cells from individuals with neurodegenerative diseases or cognitive disorders. 
• Comparing the data on brain structure, connections, and signalling between ‘healthy’ and ‘patient-derived’ organoids  can reveal the biological basis of human cognition, learning, and memory.
• They could also help decode the pathology of and drug development for devastating neurodevelopmental and degenerative diseases such as Parkinson’s disease and microcephaly.