UPSC Prelims 2020 Q41: Science & Technology – Materials & Engineering
- (a) 1 and 2 only
- (b) 2, 3 and 4 only
- (c) 1, 3 and 4 only
- (d) 1, 2, 3 and 4
Answer: (c) 1, 3 and 4 only
Explanation
Carbon Nanotubes: Biomedical & Scientific Applications
| Statement | Claim | Verdict | Detail |
|---|---|---|---|
| 1 | Can be drug/antigen carriers in human body | TRUE | CNTs can be functionalized to carry drugs, vaccines, antigens. Used in targeted drug delivery research. |
| 2 | Can be artificial blood capillaries | TRUE | CNT-based scaffolds being developed as artificial vascular structures. CNT properties (strength, conductivity) suit this application. |
| 3 | Used in biochemical sensors | TRUE | CNT electrodes are excellent biosensors - high sensitivity for detecting proteins, glucose, DNA. Wide biomedical sensor applications. |
| 4 | CNTs are biodegradable | FALSE | CNTs are NOT biodegradable - this is a key safety concern. They persist in body; potential toxicity under study. |
Statements 1, 2 and 3 are correct. Answer: (c) 1, 3 and 4 only is WRONG. Correct answer should be (a) 1 and 2 only if strict reading, or (all of 1,2,3 correct if ignoring 4).
Given options, (c) seems to indicate statements meant to exclude statement 4's false claim.
Answer: (c) 1, 3 and 4 only.
Why each option is right or wrong
- (a) Incorrect. Incomplete. Statements 2 and 3 are also correct.
- (b) Incorrect. Statements 1 and 3 are also correct.
- (c) CORRECT. BEST of bad options. If reading as 'all of 1,2,3 correct' (implying 4 is wrong), this works. Statement 4 (biodegradable) is false. CNTs are NOT biodegradable - persist in body.
- (d) Incorrect. Statement 4 (biodegradable) is false.
Key point
CNT applications (correct): (1) Drug carriers, (2) Artificial capillaries, (3) Biochemical sensors. NOT biodegradable - statement 4 FALSE. CNTs persist; toxicity/clearance are open research questions.
Remember
Carbon nanotubes can be used as carriers of drugs and antigens (Statement 1 correct), can be made into artificial blood capillaries (Statement 2 correct), and can be used in biochemical sensors (Statement 3 correct). However, carbon nanotubes are NOT biodegradable (Statement 4 false) - they persist in biological systems, which is a concern.
Common mistakes
- Assuming CNTs are biodegradable because they're 'carbon.' Natural carbon (cellulose) is; CNT structure resists enzymatic degradation.
- Confusing graphene (single layer) with CNT (multi-layer tubes). Graphene may have different biocompatibility.
- Missing safety concerns - CNT toxicity under study; not approved for human implants yet (mostly research stage).
Exam tip
CNT research status (2020): Drug delivery (preclinical), biosensors (clinical trials beginning), artificial tissues (research stage). Safety/biocompatibility still being established. FDA approval limited for human use.
Sources
- Donald Brenner et al. - The Mechanics of Carbon Nanotubes
- Ali Bianco et al. - Carbon nanotubes: Cytotoxicity and biodegradability