Limitations of Conventional Biosensors
Genetically Engineered Bacteria Powering Next-Generation Biosensors: Traditional biosensors often rely on enzymes that are fragile, costly, and difficult to use in challenging environments. Their responses are slow, particularly in complex samples, and optical signals from whole-cell sensors are not easily compatible with portable electronic devices. These limitations reduce their real-world application in field testing.
Engineered Bacteria as Signal Converters
Scientists from Imperial College London and Zhejiang University have genetically engineered Escherichia coli to function as biological platforms for electrical output. The system contains three modules:
- A sensing module that detects chemicals using molecular regulators.
- A processing module that amplifies signals.
- An output module that produces phenazines, nitrogen-containing molecules detectable through electrochemical techniques.
Static GK fact: Imperial College London was founded in 1907 and is one of the top global research universities in science and engineering.
Detecting Chemicals with Living Sensors
Two biosensors were created using this approach. The first detects arabinose, a plant sugar, and generates an electrical current within two hours. The second detects mercury ions in water using the MerR protein, enabling identification at levels as low as 25 nanomoles, which is below WHO safety limits. This detection occurs within three hours, making it faster and more reliable than traditional methods.
Static GK fact: The World Health Organization (WHO) was established in 1948 with its headquarters in Geneva, Switzerland.
Logical Operations in Bacterial Systems
Researchers also demonstrated an AND logic gate within E. coli. The sensor activated only when two specific molecules were present together. This shows the possibility of embedding biochemical computing functions into living biosensors, paving the way for advanced programmable bioelectronic devices.
Advantages and Future Applications
These biosensors can survive in contaminated environments and maintain themselves without expensive upkeep. Their electrical outputs integrate seamlessly with low-cost electronic systems, making them suitable for portable devices. Applications include environmental monitoring, medical diagnostics, and food safety testing, where traditional biosensors face significant challenges.
Static GK Tip: Food Safety and Standards Authority of India (FSSAI) was established in 2008 under the Ministry of Health and Family Welfare.
About Escherichia coli
- coli naturally resides in the intestines of humans and warm-blooded animals. While most strains are harmless, dangerous variants like Shiga toxin-producing E. coli (STEC) cause severe foodborne diseases. The strain E. coli O157:H7 is a major public health concern. STEC survives in acidic foods, grows between 7 °C and 50 °C, and is destroyed at cooking temperatures of 70 °C and above.
Static GK fact: Shigella dysenteriae, which produces similar Shiga toxins, was first identified in Japan in 1897 by bacteriologist Kiyoshi Shiga.
Static Usthadian Current Affairs Table
Genetically Engineered Bacteria Powering Next-Generation Biosensors:
| Topic | Detail |
| Researchers | Imperial College London and Zhejiang University |
| Host organism | Genetically engineered Escherichia coli |
| Output molecule | Phenazines (electrochemically detectable) |
| Sugar detection | Arabinose within 2 hours |
| Mercury detection | 25 nanomoles, below WHO safety limits |
| Logic gate | AND gate demonstrated inside bacteria |
| Applications | Environmental monitoring, medical diagnostics, food safety |
| WHO establishment | 1948, headquarters in Geneva |
| Indian regulator | FSSAI, established in 2008 |
| Harmful E. coli strain | O157:H7, linked to foodborne outbreaks |
