Biotechnological Applications in Medicine 🤖

Why this matters

Recombinant-DNA techniques let us mass-produce safe, human-identical drugs that sidestep allergy problems seen with animal products. About 30 recombinant medicines are approved worldwide, and 12 are already sold in India.👏 :contentReference[oaicite:11]{index=11}

1. Genetically Engineered Insulin 🩸

  • Human insulin contains two short chains—A and B—joined by disulfide bridges \(S\!-\!S\). :contentReference[oaicite:12]{index=12}
  • Natural production begins as pro-insulin, a longer form that loses its C-peptide to become active. :contentReference[oaicite:13]{index=13}
  • Before biotech, insulin from cattle & pigs often triggered allergic reactions.
  • In 1983, Eli Lilly built separate DNA codes for chains A and B, slipped them into E. coli, harvested each chain, then reunited them to give fully functional human insulin. :contentReference[oaicite:14]{index=14}
  • Result: a limitless, allergy-free insulin supply for people with adult-onset diabetes.

2. Gene Therapy – Fix the Gene, Fix the Problem 🧬

Gene therapy introduces a working gene into cells (or even an embryo) to replace a faulty one. :contentReference[oaicite:15]{index=15}

ADA-deficiency success story 🎉

  1. First trial (1990) helped a 4-year-old lacking adenosine deaminase (ADA), an enzyme vital for immunity. :contentReference[oaicite:16]{index=16}
  2. Doctors collected her lymphocytes, inserted functional ADA cDNA via a retroviral vector, and infused the cells back.
  3. Because lymphocytes don’t live forever, periodic top-ups are needed—unless the gene is added at the embryo stage, which could offer a permanent cure. :contentReference[oaicite:17]{index=17}

3. Molecular Diagnosis 🔬

Spot disease long before symptoms show!

  • PCR (Polymerase Chain Reaction) multiplies trace DNA/RNA from pathogens—ideal for early HIV tests, cancer-gene checks, and many other disorders. :contentReference[oaicite:18]{index=18}
  • Probe Hybridisation: a radioactive single-stranded probe binds only to its perfect DNA match. A missing signal = mutation present. :contentReference[oaicite:19]{index=19}
  • ELISA: relies on antigen-antibody “lock-and-key” binding to catch either the germ’s proteins or the host’s antibodies against them. :contentReference[oaicite:20]{index=20}

Big-picture benefits 🌐

  • No unwanted immune reactions—products are human-identical.
  • Scalable factory-like production keeps costs down and supply steady.

Important Concepts for NEET 📚

  1. Structure & recombinant manufacture of human insulin.
  2. Steps and rationale of ADA gene therapy.
  3. PCR as a sensitive early-diagnosis tool.
  4. Principle and uses of ELISA.
  5. Why recombinant drugs trump animal-derived versions.