Table 2.

Classification of stimuli‐responsive BP‐based DDSs for controlled drug release

Stimuli‐responsive types	Manners of affect		Remarks	Ref.
pH	Protonation of drugs		Subtle pH changes in different sites of the human body are advantageous for the use of stimuli‐responsive DDSs. The manner by which pH affects the drug‐release behavior of BP‐based DDSs falls into four categories: drug protonation; BP degradation; coating or capsule decomposition; and destruction of the BP–drug bond. But individual differences between patients often affect drug release efficiency.	[ 50 , 66 , 67 , 68 , 72 , 74 , 81 ]
	Degradation of BP			[ 55 , 56 , 82 ]
	Decomposition of coating or capsule			[ 46 , 55 , 66 , 67 , 74 ]
	Destruction of bonding			[ 46 , 71 ]
Near‐infrared region	Photothermal Therapy	Decomposition of coating and BP	Light irradiation has attracted a significant amount of attention as a noninvasive tool for remote spatiotemporal control of drug payload release at the desired site and time. Because its wavelength and intensity can be precisely tuned, the exposure duration and tissue location can be controlled. However, the penetrable ability and penetrable depth of light have the potential to result in a weaker release of the sample at deeper sites.	[ 46 , 68 , 74 ]
		Weaken the interactions		[ 67 , 68 ]
		Destructed hydrogels		[ 92 , 93 , 94 ]
		Accelerated the movements of drugs		[ 71 ]
	Photodynamic Therapy	Degradation of BP by ROS		[ 55 ]
Glutathione	Reduction of disulfide bonds		Large amounts of GSH trigger a series of redox reactions, which enable DDSs to release drugs precisely in response to stimulation at tumor sites. Similarly, individual differences often lead to uncertainty about the effectiveness of treatment.	[ 116 , 117 ]