Aspirant Academy

Science and Technology

Vaccines, mRNA Technology and Artificial Organs

Biology: Cell, Plant Parts, Nutrition/Reproduction, Human Physiology, Food/Nutrition, Immunity/Diseases, Microbes, Fermentation, Biotech/Genetic Engineering, GMO Ethics, Vaccines/CRISPR/mRNA, Artificial Organs

Paper II · Unit 2 Section 9 of 13 0 PYQs 31 min
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Vaccines, mRNA Technology and Artificial Organs

8.1 Vaccines — Types and Technology

How vaccines work: Introduce antigen (pathogen component) → immune system mounts response → memory cells form → on future exposure, rapid antibody response prevents disease.

Vaccine Type Mechanism Examples Advantages/Limitations
Live attenuated Weakened live pathogen BCG (TB), OPV (polio), MMR, chickenpox Strong long-lasting immunity; not for immunocompromised
Inactivated (killed) Killed pathogen Hepatitis A, IPV, influenza (injected), rabies Safe; may need boosters; less potent
Subunit Purified protein/polysaccharide Hepatitis B (recombinant), HPV (Gardasil), pneumococcal Safe, specific; need adjuvants
Toxoid Inactivated toxin Tetanus, diphtheria Long-lasting immunity to toxins
Viral vector Non-replicating virus carrying antigen gene AstraZeneca (Oxford) ChAdOx1 for COVID; Covishield; Sputnik V Can cause vector immunity on repeat doses
mRNA Lipid nanoparticle-delivered mRNA encoding antigen Pfizer-BioNTech BNT162b2; Moderna mRNA-1273 Rapid production; no live pathogen; mRNA does not alter DNA
DNA vaccine DNA plasmid encoding antigen ZyCoV-D (India's DNA vaccine for COVID; world's first approved DNA vaccine — 2021) Novel; need electroporation for delivery

India's Vaccine Achievements

  • Covaxin (BBV152): Whole-inactivated SARS-CoV-2 vaccine developed by Bharat Biotech + ICMR-NIV; approved January 2021 by DCGI; India's indigenous COVID-19 vaccine.
  • ZyCoV-D: World's first DNA vaccine for any disease; approved August 2021; developed by Zydus Cadila (Ahmedabad).
  • CORBEVAX: India's first RBD protein subunit vaccine; developed by Biological E Ltd., Hyderabad; approved January 2022; competitively priced ($1.5 per dose).

8.2 mRNA Vaccine Technology

Traditional vaccines take 10–15 years to develop. mRNA vaccine technology can be designed and manufactured in weeks once the pathogen genome is sequenced.

mRNA Vaccine Mechanism

  1. Design: Identify the target antigen gene (e.g., SARS-CoV-2 spike protein gene); synthesise mRNA encoding this protein.
  2. Delivery: Wrap mRNA in lipid nanoparticles (LNPs) — oil-like spheres that protect mRNA from degradation and enable entry into cells.
  3. In the cell: Ribosomes translate mRNA → produce spike protein.
  4. Immune response: Immune system recognises spike protein as foreign → mounts antibody + T cell response → memory cells formed.
  5. mRNA degradation: mRNA is naturally degraded within days. It never enters the nucleus and cannot integrate into DNA.

Key developers: Dr. Katalin Karikó (BioNTech) and Dr. Drew Weissman (University of Pennsylvania) — Nobel Prize in Physiology or Medicine 2023 — for discoveries enabling mRNA vaccine development (modified nucleoside bases reducing immunogenicity of mRNA).

Future mRNA Applications

  • Cancer vaccines (personalised neoantigen mRNA vaccines — under Phase 2/3 trials at Moderna/BioNTech)
  • HIV, influenza, RSV vaccines under development
  • Protein replacement therapies for rare genetic diseases
  • India: mRNA vaccine technology hub established under IndiaAI and DBT — Serum Institute, Biological E developing mRNA vaccine capacity

8.3 Artificial Organs

Hemodialysis (Artificial Kidney)

Blood is pumped through a semipermeable membrane (dialyzer); small molecules (urea, creatinine, excess water, electrolytes) diffuse out; large proteins and cells are retained. Used for patients with chronic kidney disease (CKD) or acute kidney failure. India has ~220,000 patients on dialysis (2023).

Cochlear Implant (Artificial Ear)

An electronic device is surgically implanted in the cochlea; it converts sound to electrical signals and stimulates the auditory nerve, which is perceived as sound. Effective for severe-to-profound sensorineural hearing loss. India's National Programme for Prevention and Control of Deafness provides subsidised implants.

Cardiac Devices

  • Pacemaker: Electronic device implanted under skin to regulate abnormal heart rhythms by delivering electrical impulses.
  • Ventricular Assist Device (VAD): Mechanical pump assisting a weakened ventricle; bridge to transplant.
  • Total Artificial Heart (TAH): Replaces both ventricles — SynCardia TAH is FDA-approved.

3D Bioprinting

3D bioprinting uses bio-inks (living cells + hydrogel scaffolds) to print three-dimensional tissue structures layer by layer. Current achievements include skin patches (wound healing), cartilage, cornea models, and mini-liver organoids for drug testing. Full organ printing (kidney, liver, heart) remains at research stage due to challenges in vascularisation (creating blood vessel networks within thick tissues).

Prosthetics

Advanced robotic prosthetic arms with neural interface (e.g., DEKA Arm — FDA approved 2014) connect to remaining nerves, allowing intuitive control. JAIPUR FOOT (Jaipur, Rajasthan) is a world-renowned low-cost prosthetic foot developed by Dr. P.K. Sethi and master craftsman Ramchandra Sharma Vishwakarma. It is used by 1.3 million+ amputees in 26 countries.