In which of the following are hydrogels used?

1. Controlled drug delivery in patients

2. Mobile air-conditioning systems

3. Preparation of industrial lubricants

Select the correct answer using the code given below.

The correct option is 1 and 2 only.

Hydrogels are three-dimensional, hydrophilic, polymeric networks capable of holding large amounts of water or biological fluids. Due to their unique physical and chemical properties, they find application in a variety of fields:
1. Controlled drug delivery in patients: Hydrogels are highly biocompatible and can be engineered to release loaded pharmaceutical agents in response to specific physiological triggers (such as pH, temperature, or enzyme presence). This makes them widely used in controlled and targeted drug delivery systems.
2. Mobile air-conditioning systems: Advanced hydrogels are utilized in innovative cooling technologies, such as evaporative cooling systems and thermal energy storage, because of their high water absorption and retention capabilities. They help regulate humidity and provide sustainable cooling solutions in mobile and compact air-conditioning units.
3. Preparation of industrial lubricants: Generally, industrial lubricants require stable liquid or semi-solid formulations with high shear stability and thermal resistance, typically derived from oils, synthetic esters, or traditional greases. Hydrogels, which are water-based structures, are not standard or primary materials for industrial lubrication due to their susceptibility to dehydration, microbial degradation, and poor mechanical stability under high friction/load conditions.

Therefore, statements 1 and 2 are correct, while statement 3 is incorrect.