Polydopamine may be easily functionalized with a range of nanomaterials for synergistic cancer therapy, in addition to its exceptional photothermal effects
Authors: Dowaidar Moataz 
Published: June 2021

This review carefully reviewed recent polydopamine (PDA) research, including targeted therapy and cancer synergistic medications. Recent breakthroughs in photothermal treatment coupled with complex therapies such as gene therapy, radiation, and especially immunotherapy were highlighted. Due to their exceptional biocompatibility, degradability, low toxicity and high photothermal conversion efficiency, facile oxidative self-polymerization of dopamine can create PDA and serve as an excellent nanocarrier or photothermal cancer treatment agent. Due to its high adhesive capacity, PDA may be easily functionalized with a range of nanomaterials for synergistic cancer therapy, in addition to its exceptional photothermal effects. Although PDA-based multifunctional nanoplatforms have gained interest for synergistic cancer therapy, such as chemo-photothermal treatment and photodynamic-photothermal treatment, discovering novel uses for PDA remains tough. First, despite its easy and mild process of synthesis, large-scale synthesis with uniform size and thickness is challenging owing to the absence of consistent quality control standards. Second, due to the strong adhesive properties of PDA, multifunctional nanoplatforms are prone to aggregating in a solution. Third, to improve PDA's clinical application, its safety should be fully researched. Before being deployed in clinical settings, PDA-based multifunctional systems need additional research. A PDA-based multifunctional platform for better synergistic cancer treatment is a forward-looking strategy. In particular, PDA-based immunotherapy systems will remain a research center.Besides immunotherapy, in recent years, the integration of cancer diagnosis and treatment has gained a lot of publicity. Polyphenols have been proven to suppress tumor development and interact with metals such as Fe3+, Pt4+, Cu2+, etc (MPNs). MPNs are biocompatible, functional, pH-responsive and can escape endosomes. PDA has the potential to develop MPNs with contrasting magnetic resonance agents like gadolinium due to the enormous quantity of catechol groups on its surface, allowing magnetic resonance imaging. Polyphenols also have tumor-inhibiting effects, and PDA's photothermal activity can ablate tumors. Consequently, PDA-based MPNs might be a promising way to integrate diagnosis and treatment. Moreover, polydopamine can crosslink acrylamide and other polymers to form anticancer and antibacterial hydrogels. Increasing the stickiness of polydopamine hydrogels is now underway, paving the path for self-adhesive bioelectronics hydrogels. Bioelectron self-adhesion and other capabilities such as self-healing, transparency, and bacterio-toxicity may be supplied to polydopamine hydrogels by altering phenolquinone's redox process. A prospective future trend is using self-adhesive polydopamine hydrogels with current bioelectronic materials. We think that polydopamine hydrogels will eventually advance from skin patches to implantable integrated bioelectronics.