In accordance with certain embodiments of the present disclosure, a method for intracellular delivery of small molecules is provided. The method includes encapsulation of small molecules in a thermally responsive nanocapsule by decreasing the temperature of the nanocapsule to increase the permeability of the nanocapsule and allowing the small molecules to be suck into or diffuse into the nanocapsule. The nanocapsule is delivered into a cell by increasing the temperature of the nanocapsule. The small molecules are released from the nanocapsule into the cell in a controllable manner by cooling and heating treatments.