Sodium alginate beads are formed through a process called ionotropic gelation. A sodium alginate solution is dropped into a calcium chloride solution, where the calcium ions cross-link with the alginate chains to form gel beads. The beads are then washed to remove excess calcium ions. Bead properties like size, hardness, and diffusion rate depend on the concentration of sodium alginate used. Sodium alginate beads find applications in drug delivery, cosmetics, biotechnology, and the food industry due to their ability to encapsulate and control the release of various active ingredients.

1. Sodium Alginate Beads
• Sodium Alginate is a salt of alginic acid, which is a linear polymer
composed of two monosaccharides: D-mannuronic acid and guluronic
acid.
• In the experiment, sodium alginate solution is mixed with a calcium
chloride solution to form microencapsulated beads.
• This is achieved by a process known as ionotropic gelation, where the
calcium ions from the calcium chloride solution cross-link the alginate
chains, forming a gel-like structure.
• The resulting beads are then washed with distilled water to remove
any excess calcium ions.

3. Procedure
• Prepare 2% w/v and 5% w/v sodium alginate solution by dissolving 2gm
and 5gm of sodium alginate in 100 mL of distilled water respectively.
• Prepare a 2% w/v calcium chloride solution by dissolving 2 g of calcium
chloride in 100 mL of distilled water.
• Fill a syringe with the sodium alginate solution and use a dropper to drop
small droplets of the solution into the calcium chloride solution.
• Stir the mixture gently using a stirring rod.
• Observe the formation of the microencapsulated beads and collect them
using a dropper.
• Wash the beads with distilled water to remove any excess calcium ions.
• Transfer the beads to a glass petri dish for further observation.

4. Observation
1. Formation of spherical beads of smooth surface and uniform size observed.
2. When concentration of Sodium Alginate increases :
• Hardness Increases
• Cross-linking increases
• Rigidity increases
• Size decreases
• Lightness and yellowness decreases
• Slower rate of diffusion(drug delivery)
• Vice-versa
3. pH
• Decrease in pH cause protonation of carboxyl group and reduced bonding with divalent ions i.e.
Calcium ions.
• Vice-versa
• Mechanical Properties and Biocompatiblity : Presence of surfactants, protein, polymer,
phosphate or chloride ions.

5. Applications
• Pharmaceuticals
• Effective and controlled, targetted drug delivery.
• Protection of drug in stomach from degradation.
• Cosmetics
• Controlled release of active ingredients such as fragrances, vitamins, and skin-care agents.
• Biotechnology
• For the immobilization of enzymes and cells(Increases life span).
• Food Industry
• Encapsulating flavors, other sensitive ingredients.
Learning Outcomes:
Upon completion of this topic, there must be a clear understanding of-
• Method to formulate Microencapsulated sodium alginate beads.
• Factors influencing beads formation and Applications.