Table 1.

LNP preparation methods

Method	Raw lignin	Solvent/antisolvent	Morphology, size	Surface properties	Applications	Refs.
Solvent shifting (nanoprecipitation, solvent exchange)	KL	Acetone and water/water	Spherical, ca. 100 nm	Hydrophilic, pH 4.3 ζ ca. -25 mV pH 3.9 ζ ca. -27 mV	Nanocomposites Pickering emulsions, drug delivery	[61, 62]
	KL		Spherical, ca. 244 nm	ζ ca. -37 mV	Component of biomaterial ink for 3D printing of scaffolds for cell culture	[78]
	KL		Spherical, ca. 109 nm, ca. 70.8 nm	ζ ca. -36 mV ζ ca. -37 mV	Water purification	[79]
	KL		Spherical, ca. 91 nm,	pH 4.0 ζ ca. -30 mV	Model surfaces	[80]
	KL		Spherical, ca. 97 nm,	ζ ca. -40 mV	Biocatalytic particles for SET-LRP, Pickering emulsions	[81]
	KL(+ BADGE)		Spherical, core–shell From 71 to 113 nm	ζ from ca. -32 mV to ca. -37 mV	Covalent surface modification, adhesives	[82]
	KL	THF and water/water	Spherical, 177–300 nm	Hydrophilic, smooth, ζ = 33–45 mV at pH 7	Pickering emulsions, immobilization of biocatalyst, adhesives	[55] [83] [84]
	KL		Spherical, ca. 142 nm	pH 3.9 ζ ca. -24.4	Model surfaces	[80]
	OSL		Spherical, smooth, aggregated, ca. 219 nm		Enzyme immobilization, biosensing	[85]
	KL		Spherical, 200–500 nm	Hydrophilic smooth, ζ ca. -60 mV		[52]
	Acetylated AL	THF/water	Spherical, 110 nm Spherical	Hydrophilic Hydrophilic	Potential in drug delivery and microencapsulation photo-protection agent	[51] [86]
	Organic acid lignin		100–600, 600–5000, 400–2000 nm
	KL	THF and EtOH and water/water	Spherical, 200 nm	Hydrophilic smooth, ζ ca. -40 mV	Pickering emulsions, polymer composites	[63]
	Carboxylated KL	THF/water	Spherical, 167 nm		Biomedical applications, drug delivery	[87]
	EHL	Acetone and water/water or acetone	Spherical			[67]
	AL	EtOH and water/water	Spherical, 50–100 nm, 250–350 nm	Hydrophilic smooth, ζ ca. − 43 mV	Drug delivery	[64]
Reverse micelles	AL	Dioxane/cyclohexane	Spherical	Hydrophobic, smooth	Nanocomposites: UV-blocking, optimization of rheological properties	[68]
Acidification, pH shifting	KL (Indulin AT)	EG/HCl aq	Aggregate-like clusters	Uneven surface	Drug delivery, sorbents for heavy metal ions	[50]
		NaOH aq/HNO3 aq	Aggregate-like clusters	Uneven surface
	KL	EG/ HNO3 aq	Aggregate-like clusters, 84 nm	uneven surface, ζ ca. -33 mV	Antimicrobial silver-infused nanoparticles	[69]
	KL	EG/HNO3 aq	Aggregate-like	uneven surface, partly hydrophilic,	Surface functionalization with, e.g., antimicrobial agents	[88]
	AL	NaOH aq/H2SO4 aq	Aggregate-like 768.4 ± 97.8 nm, 725.4 ± 51.3 nm	ζ ca. 2.8 mV ζ ca. − 13.4 mV	Emulsification, Pickering emulsion, template for synthesis of polymer capsules	[89]
Aerosol flow reactor, dry particles	Hydrothermal treatment	Acetone/none	Spherical	Smooth, hydrophilic, ζ ca. -35 mV		[38]
	KL, AL, OSL	DMF/none Water/none	Spherical, 30 nm-2000 nm	Smooth surface, hydrophilic KL ζ ca. -40 mV OSL ζ ca. -36 mV	Pickering emulsions	[46] [90]
	KL	DMF/none	Spherical, 50–2000 nm	Smooth	Coatings	[91]
Aerosol + freezing	AL	DMSO/water	Spherical particles and capsules, 80–200 nm	Smooth, hydrophilic, negatively charged	UV absorption, drug delivery	[71]
CO2 precipitation	KL	DMF/CO2	Coalesced quasi-spherical, ca. 38 nm	Uneven surface, hydrophilic	UV absorption	[92]
Mechanical treatment
Sonication	AL	Water	Irregular, 10–50 nm	Uneven surface		[73]
Homogenization	KL	Water	Irregular, < 100 nm	Uneven surface	Nanocomposites: improvement of thermal and mechanical prop	[74]
Ball milling			Irregular, ca. 10 nm	Uneven surface		[48]
Low temperature milling			Irregular, ca. 10 nm	Uneven surface		[93]