Table 3.

Summary of advantages and challenges of PTT in cancer treatment

Advantages	Challenges
Photo-responsive materials are localized in the tumor area. [118, 119] Targeting ligands such as antibodies, single-chain fragments of antibodies, carbohydrates, etc. can be furnished on AuNPs to combat low targeting ability [81]	Low targeting ability due to the hindrance caused by the dense interstitial structure of the tumor and lack of vessels in the tumor [80] and defects of photosensitive materials [120]
Produces high local temperatures with no or minimal influence on healthy cells and tissues [119]	Possible thermal damage to normal tissue [120]
PTT can be combined with other types of therapies with different mechanisms of action, which results in a synergetic treatment effect [5, 88, 121]	Insufficient photothermal effect and limited penetration depth of light in biological tissues [88, 120]
Upgradable thermal capacity is achieved by manipulating the size of gold nanoparticles and modifying their surface properties for the targeted location of the tumor [78]	Poor photothermal stability [78]. Can lose their photothermal conversion ability upon repetitive NIR radiation [79]
Compensate for poor drug loading capacity with remarkable light-absorbing and scattering abilities [67]	AuNPs have a poor drug loading capacity, limiting the use of AuNPs as drug carriers [79]