Table 2.

Examples of application of non-viral vector-based mRNA delivery system.

Types	Base	Structure	Application	Advantage	Disadvantage	Ref.
Lipid-based delivery system	Cationic lipids
	DOPE		Activation of DC maturation and inflammatory mechanisms through interferon-α (IFNα) release by functional RNA-LPX.	Formation of colloidally stable nanoparticulate RNA-LPX with reproducible particle size and charge.	Immediate formation of large aggregates in near-neutral RNA-LPX, rendering them unstable.	[105]
	DOTMA
			RNA-LPX for HPV16 vaccine.	Suitability for RNA study attributed to the cationic net charge.	Depending on the mixing ratio of lipid and RNA, there is a range in which the carrier is unstable.	[106]
			A potential DC-targeting delivery system for mRNA vaccine.	Safety in vitro.	Limitation in the in vivo delivery profile and anti-tumor efficacy.	[107]
	DOTAP
			mRNA-based vaccine for anti-tumor immunity.	Dual function of protecting mRNA from degradation and enhancing DC uptake.	High level of cytotoxicity from the DOTAP/Chol/DSPE-PEG-2000 formulation.	[108]
	ePC
			Enhancing intracellular delivery mediated by shock waves.	Capability of delivering mRNA to diverse cancer cell types in vitro.	Cell type-dependent transfection efficiency.	[110]
	Anionic lipids
	18PA, 14PA, and 18BMP		Selective organ targeting for tissue-specific mRNA delivery and CRISPR-Cas gene editing.	Capacity for delivering therapeutic nucleic acids.	Inability to design nanoparticles for targeted tissue delivery.	[113]
	Ionizable lipids
	DLin-MC3-DMA (MC3)		Delivery of nucleic acid-based drugs.	Facilitation of endosomal escape for efficient nucleic acid delivery to the cytosol.	Depending on the mouse strain, toxicity of LNP to the fetus may occur.	[116]
			Efficient transfection of retinal pigment epithelium (RPE).	Potential for rational design of optimal cell-specific gene delivery.	Rapid elimination of dissociated components upon entry if nanoparticles exhibit instability.	[117]
	DSPC		Effective response to virus infection.	Favorable tolerability of the system compared to alternative non-viral delivery systems.	The effectiveness of vaccines against mutated viruses may be reduced.	[121], [122]
	OF-02		Promising delivery vehicle for therapeutic mRNA delivery to the liver.	Most potent mRNA delivery vehicle reported to date in the scientific literature.	Absence of reports on the creation of a new series of ionizable lipids specifically designed for enhancing mRNA LNP delivery in vivo.	[127]
	A2-Iso5-2DC18 and A12-Iso5-2DC18		Optimal reduction of E7 mRNA expression, prevention of human papillomavirus, and stimulation of the STING pathway.	Efficient delivery of mRNA.	LNP itself can trigger APC maturation.	[128]
	Lipid 5		Improved lipid delivery and rapid elimination in non-human primates.	Good balance of delivery efficiency and pharmacokinetics.	The efficiency of LNP delivery to organs other than the liver is unknown.	[131]
Polymer-based delivery system	PEI		Efficient generation of “footprint-free” iPSCs using GO-PEI-RNA complexes for mRNA delivery.	Strong binding capacity to nucleic acids, effective uptake by cells, and excellent proton sponge effect for the endosomal release of DNA or RNA.	Significant decrease in cell viability and apparent increase in innate immune response gene expression.	[133]
	PLGA		FDA-approved polyester type.	Carriers for DNA delivery.	Absence of reports on intramuscular administration of PLGA-encapsulated plasmid DNA.	[140]
	Poly-(β-amino ester) (PBAE)		CAR or TCR mRNA delivery system for reprograming of circulating T cells	Less toxic than other nondegradable cationic polymers.	A scale-up manufacturing process that can be applied clinically is essential.	[142]
	Chitosan		Promising therapeutic approach for cystic fibrosis.	Biodegradable characteristic.	Depending on the route of administration, the efficiency of hCFTR expression varies.	[149]
Others	Gold nanoparticles		Rapid delivery of mRNA using VNB photoporation method.	Promising approach for safe and efficient intracellular mRNA delivery in cells.	Necessity to influence T cell homeostasis and therapeutic functionality.	[155]
			An indirect method of enhancing mRNA translation.	Enhancement of mRNA translation.	Insufficiency of high cellular uptake and endosomal escape from endocytic vesicles.	[157]
	Silica nanoparticles		Analysis of mRNA delivery efficiency according to particle size and pore size of mesoporous SiNPs	SiNPs can be synthesized at room temperature.	The efficiency of mRNA delivery in vivo has not been confirmed.	[160]
			By adding functional groups to SiNPs, new functions were added.	As the tetrasulfide of SiNPs removed glutathione, the translation efficiency of the delivered mRNA increased.	Cytotoxicity was observed at concentrations higher than 40 mg/ml of SiNPs.	[161]
			Self-assembling mesoporous silica-cationic polymer-mRNA complex	Tissue-specific delivery of mRNA to the pancreas and mesentery without toxicity.	Target organs are limited.	[162]
			Macrophage-targeted mRNA delivery	Silica shells protected mRNA from enzymatic degradation.	The mechanism of macrophage-specific mRNA transfection has not been elucidated.	[163]
	Exosomes		Anti-inflammatory effects of IL-10 overexpression in atherosclerosis.	Potential to aid in disease diagnosis.	Unknown as physiological purpose of generating exosomes.	[172]
			mRNA loading in exosomes via secreted after the endocytosis of LNP-mRNA system.	Promising in vivo delivery carriers for siRNA-based therapies.	Limitation of small size.	[173]
			Potential therapeutic effects for stroke.	Low toxicity and immunogenicity.	Challenges in storage and transportation.	[174]
			Method for producing large-scale mRNA-encapsulating exosomes through cellular nanoporation.	Favourable pharmacokinetic and immunological properties.	Low yield observed when incorporating particularly large mRNA.	[175]