Table 1.

Various types of nanomaterial substrates used for the detection of drugs or metabolites by LDI-MS.

Category	Probe/substrate	Nanomaterial properties or LDI process	Analytes	LODa	References
Metal-based	Au nanoshell	plasmonic, generation of hot carriers conductive, nanostructured, and transparent	amino acids and carbohydrate	3–30 pmol	[8]
	ITO		lipids, glycerol, and creatinine	6 mg L−1	[9]
	TiO2 nanowire	photoabsorption	benzylpenicillin	0.4 ng mL−1	[18]
	TiO2 NPs	photoabsorption	18 candidate metabolites from bacteria	n/a	[46]
	HSA-Fe3O4 NPs	affinity towards analytes molecules	phenytoin, ibuprofen, camptothecin, warfarin	5 μM	[19]
	ZnO, TiO2, Fe2O3, CeO2	small size and large surface area, strong UV absorption	amitriptyline hydrochloride, imipramine hydrochloride, nortriptyline hydrochloride, promazine hydrochloride	n/a	[44]
	Au NPs, Ag NPs, Pd NPs, Pt NPs	photoabsorption, binding affinity, internal energy transfer	benzylpyridinium chloride	n/a	[39]
	Au NPs	photoabsorption, high salt tolerance	progesterone, testosterone, cortisol, ribose, glucose, maltose, 5-HIAA, tryptophan, GM1, bradykinin, angiotensin I/II, substance P	46.5–5115.7 nM	[40]
	Au NPs	photoabsorption	palmitic acid, oleic acid, stearic acid, verapamil	n/a	[41]
	Au NPs/KBr	photoabsorption	acetaminophen, noscapine, loratadine, coptisine, berberine, palmatine	n/a	[42]
	ARRO SupraNano™	photoabsorption	cocaine, methadone, aspirin, paracetamol, caffeine	n/a	[43]
	TiO2-dopamine monolith	dopamine enhanced UV absorbance, selective binding of Lewis bases	fatty acids, cholesterols, ceramides, diacylglycerols, phosphatidylethanolamine, amino acids, alkaloids, peptides, lipids	n/a	[45]
Carbon-based	graphene, GO	photoabsorption, electron transport	scutellarin, wogonin, ferulic acid	n/a	[67]
	aptamer modified GO	enrichment, photoabsorption	cocaine, adenosine	n/a	[21]
	graphite rods	photoabsorption	9-phenylacridine	0.1 pmol	[30]
	C-Dots	in situ energy transfer via functional groups	mefenamic acid	0.5 ng	[31]
	GO/MWCNT hybrid films	photoabsorption; functional groups of GO	cellobiose, leuenkephaline, glutamine, glucose, leucine, lysine, D-mannitol, phenylalanine	n/a	[33]
	CNT, C60, PGC, G, HOPG, ND	phase transition	nenzylpyridinium halide derivatives	n/a	[34]
	Graphene, GO, rGO	size dependent, photoabsorption	flavonoids, coumarin derivatives	10 ppm	[35]
	Graphene, GO	photoabsorption, electron transport	tetracycline	2 nM	[51]
	Graphite dots	strong UV absorption, hydroxyl groups provide high stability and favorable ΔG for analyte deprotonation	glucose, Ala-Gln, oligosaccharides; puerarin, daidzein, dihydrodaidzein	n/a	[52]
	N-doped graphene	proton transfer, photoabsorbance process	fatty acid, peptide, epiandrosterone, testosterone, methyltestosterone, nilotinib	n/a	[53]
Silicon/Silica/Semiconductor	Nanostructured silicon	desorption ionization on porous silicon mass spectrometry imaging (DIOS-MSI)	methadone, heroine, EDDP	n/a	[17]
	Mesoporous germanium	photoabsorption	cocaine	1.7–3.5 ng mL−1	[20]
	Silicon nanopillar arrays	photoabsorption	peptides, methadone	32 ng mL−1	[22]
	Nanoporous GaN–Ag composite	high UV absorption	R6G, adenine	<50 pmoles	[23]
	Silicon nanopost arrays	nanophotonic interaction	cAMP, acetylcholine, glucose, cholesterol, amino acids, small organic acids, phospholipids, fatty acids	n/a	[29]
	Porous silicon	high UV absorption	methadone	14.74–19.50 ng mL−1	[36]
	Nanostructured Silicon	nanostructure-initiator mass spectrometry (NIMS)	rapamycin, tigylglycine, N-acetyl-glutamic acid, uridine monophosphate, isobutyrylcarnitine, stearic acid, D-glucose	n/a	[37]
	Ordered silicon nanocavity arrays	desorption ionization on porous silicon-mass spectrometry (DIOS-MS)	benzylpyridinium salts, DPPC, angiotensin III	n/a	[56]
	Ordered silicon nanocavity arrays	desorption ionization on porous silicon-mass spectrometry (DIOS-MS)	methamphetamine, cocaine, MDMA	n/a	[57]
	Nanoporous silicon microparticles	photoabsorption	methamphetamine, cocaine, MDMA, methadone, EDDP	~20 ng mL−1	[58]
	hydrophobic silica powder	photoabsorption	nicotine	n/a	[60]
	DHB + porous silicon	matrix-enhanced nanostructure initiator mass spectrometry (ME-NIMS)	pentamidine	0.005 μM	[61]
	Nanostructured Silicon	morphology-driven controlled nanostructure-initiator mass spectrometry (NIMS)	arginine, palmitylcarnitine, streptomycin, bradykinin, angiotensin, neurotensin	n/a	[62]
	Nanoporous silicon films	perfluoro coating assisted desalting	taurine, aspartic acid, malic acid, glutamic acid, histidine	~1 μM	[63]
Composite-based	PAN/Nafion®/CNT	photoabsorption	verapamil, methotrimeprazine, propranolol, chloroprothixene	220 fM	[13]
	Au/PAA-GO film	photoabsorption, thermal conductivity	cellobiose, mannitol, glucose, leucine, phenylalanine, glutamine, leuenkephalin	n/a	[50]
	SiO2@Ag particles	plasmonic resonance	mannitol, glucose	100 ng μL−1	[65]
	Ag-DIOS	silver adduct assisted	bromoisatin, lipids, cholesterol	n/a	[66]
	plasmonic gold chip	plasmon resonance, hot carrier production	amino acids, carbohydrates, metabolites	n/a	[64]
Mass tag	thiolalkane-Au NPs	thermal desorption of ligand	enrofloxacin, ciprofloxacin	50 mg kg−1	[7]
	Fib–Au NPs–MCEM	NP fragmentation	thrombin, anticoagulants	n/a	[47]

^an/a: not available.