Table 2.

G-based PAI. Each research was classified by G types, modification, abbreviation, theragnosis multimodalities, PA signal enhancement, novelties, maximum cytotoxicity concentration, and test species. AuNP, gold nanoparticle; APTES, 3-aminopropyltriethoxysilane; AuNS, gold nanostar; BSA, bovine serum albumin; CCK-8, cell counting kit 8; CS, chitosan; DODAB, dimethyldioctadecylammonium bromide; DOPE, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine; DOX, doxorubicin; FA, folic acid; FL, fluorescence; GNP, graphene nanoparticle; GQD, graphene quantum dot; GSP, gold superparticle; ICG, indocyanine green; IONP, iron oxide nanoparticle; MRI, magnetic resonance imaging; NR, nanorod; ND, nanodiamond; NIR, near infrared; O-MWGNR, oxydized graphene multi-walled nanorod; PAA, polyacrylic acid; PBS, phosphate-buffered saline; PDA, polydopamine; PEG, polyethylene glycol; PET, positron emission tomography; PT, photothermal; PTT, photothermal therapy; PVP, polyvinylpyrrolidone; US, ultrasound; SERS, surface-enhanced Raman scattering; rGO, reduced graphene oxide; TPI, two-photon imaging.

Types	Materials Modification	Multimodalities	PA Enhancement (Fold/Control)	Novelties	Cytocompatible Concentration	Test Species	Ref.
GO	ICG and FA	PTT	10/PBS at cell	High absorbance in the NIR region and cancer targetability	≤20 μg/mL	HeLa	[71]
	ICG and integrin αvβ3	FL	5/GO at water	FL quenching via FL resonance energy transfer, selective tumor cell targetability, and apoptosis-mediated cancer ablation	≤21.5 μg/mL	U87-MG	[74]
	FA and CS	PTT	N/A	Stability in water and biodistribution and long-term observation of tumor recurrence inhibition	N/A	MDA-MB-231-BALB/c nude	[79]
	Bi2Se3 and PVP	CT, PTT	N/A	Little hemolytic activity and in vivo toxicity and hydrophilicity	≤150 μg/mL	HeLa-BALB/c nude	[86]
	MnWO4 and PEG	MRI, PTT, chemotherapy	N/A	High drug loading capacity, pH- and NIR-stimulated drug release, and biodistribution and water content	≤200 μg/mL	HUVEC, 4T1, and 4T1-athymic nude	[87]
	Silica and AuNP	FL	2.3/AuNP@SiO2 at water	Controllable photoluminescence, high-resolution PA signal, and size-dependent electromagnetic field intensity	N/A	N/A	[95]
	APTES, silica, and PAA	TPI	N/A	High dose of dye loading and TPI for high-resolution depth penetrating imaging	N/A	HeLa, chicken breast	[96]
rGO	AuNR	PTT	2.5/AuNR at PBS	Higher light absorption and electromagnetic field generation and simultaneous application by overlapping absorbance peak for PA and US application	N/A	BALB/c mice	[103]
	ICG and PDA	PTT	20/GO at mouse tumor	Enhanced light absorbance by incorporation of ICG and In vivo tumor suppression without toxicity	N/A	4T1 and 4T1-BALB/c	[102]
	DOX and AuNR	FL, US, PET, PTT, chemotherapy	20/AuNR	Sequential drug release system, high drug loading capacity, and exceptional versatility	≤6.4 μg/mL	U87 MG and U87 MG-mouse	[104]
	AuNP and PEG	SERS, PTT	Mouse ovarian cancers	Availability in the second NIR region by plasmonic coupling and fast clearance due to particle dissociation	N/A	SKOV-3 and SKOV-3-BALB/c nude	[105]
	DODAB/DOPE–FA and AuNS	PTT	Mouse pancreatic tumor	PAI-guided PT/gene synergistic therapy (G12V delivery) and receptor-mediated cancer targeting	N/A	Capan-1 and Capan-1-BALB/c nude	[115]
	GSP and PEG	PTT, US	10/PBS	Exceptional chemical properties by plasmonic coupling of the self-assembled composites and GO-GSP emulsion method	≤100 μg/mL	U87MG and U87MG-BALB/c nude	[118]
	BSA	US, PTT	1.5/blood at mouse tumor	High stability and low cytotoxicity and passive targeting	≤80 mg/L	MCF-7 and MCF-7-mouse	[119]
	IONP and PEG	FL, MRI	N/A	Strong NIR absorbance and superparamagnetic properties	N/A	4T1-mouse	[126]
GQD	Nitrogen and FA	FL, PTT	3/N–GQD at cells	Uniform and small size (5 nm), strong quantum yield, and low cytotoxicity	≤500 μg/mL	HeLa and A549	[127]