In the treatment of liver-specific diseases, although LNP delivery systems have significant liver targeting and the current research and development progress is rapid, their clinical application remains relatively limited [
165,
166]. Several factors contribute to this issue. First, it is difficult to precisely target specific liver subsets, such as hepatic stellate cells, relying solely on natural metabolic pathways. Moreover, over 50% of LNP are nonspecifically cleared by Kupffer cells [
167,
168]. The structural changes of liver sinusoid in pathological states such as cirrhosis further hinder the delivery efficiency. Second, immunogenicity poses a key obstacle. The immunogenicity of LNP is not triggered by a single component but rather from the synergistic action of its core components, including ionizable lipids, phospholipids, cholesterol, PEG-lipids, which are recognized by the innate immune recognition pathways. Ionizable lipids are the main effector components of LNP in activating the innate immunity, and their structural differences directly determine the intensity and type of the immune response. Research from the United States Armed Forces Medical University confirmed that commonly used ionizable lipids, such as SM102 and ALC315, activate the MyD88-dependent signaling pathway by binding to TLR4 on immune cells. This binding induces the activation of NF-κB and IRF transcription factors, promoting the release of pro-inflammatory factors such as IL-6 and tumor necrosis factor-alpha (TNF-α) [
169]. Furthermore, in a 2022 study, it was found that SM102-type LNP stimulate IL-1β release from human peripheral blood mononuclear cells, while MC3-type LNP does not exhibit this effect [
170]. This is closely related to the chain length and charge distribution of the lipid tail. Auxiliary lipids also regulate the "quality" and "quantity" of the immune response by altering the membrane structure and biological distribution of LNP. Negative phospholipids (such as dioleoylphosphatidylserine (DOPS) and dioleoylphosphatidylglycerol (DOPG)) can target secondary lymphoid organs, enhancing uptake by DCs. Specifically, DOPS-LNP can activate CD8⁺ T cells, while DSPC-LNP is more likely to induce humoral immunity [
171]. Although PEG modification can prolong the circulation time of LNP, it also triggers anti-PEG immune response, presenting a key challenge for repeated administrations. Pre-existing or repeatedly induced anti-PEG antibodies can bind to the PEG chain on the surface of LNP, activating the complement cascade reaction and leading to phagocytosis and clearance by macrophages. Reducing the proportion of PEG (from 1.5% to 0.5%) can enhance the production of antigen-specific antibodies, but excessive PEG (>2%) may inhibit the uptake of LNP by DCs and weaken the immune activation effect. Repeated administration can accelerate the clearance of anti-PEG antibodies and ionizable lipids, causing endosomal damage and activating the release of pro-inflammatory factors such as IL-6 and TNF-α, which increases the risk of toxicity and tolerance to repeated administration [
172]. Finally, the complex production process, large disease heterogeneity, and high long-term safety regulatory requirements have delayed the transformation process from laboratory to clinical practice [
173]. Addressing these challenges involves investigating various factors, such as lipid composition, surface modifications, and particle size, all of which can influence the performance and biodistribution of LNP [
174]. Furthermore, as research progresses, there is a pressing need for comprehensive
in vivo studies to assess the long-term effects and therapeutic outcomes of LNP-based mRNA delivery systems in diverse patient populations [
175]. Collaborations between academic institutions and biotechnology companies may accelerate the translation of these findings into clinical settings [
176]. Looking ahead, the future of LNP-mediated mRNA therapies for liver disease treatment appears promising [
177]. With continued innovation and optimization, these systems could not only improve the management of existing liver diseases but also pave the way for novel therapeutic interventions, including gene editing and personalized medicine approaches. The successful application of LNP delivery systems in clinical practice could revolutionize the treatment landscape for liver diseases and beyond, ultimately enhancing patient outcomes and quality of life. Future studies need to further explore the design of liver disease specific LNP: By adjusting the proportion of selective organ targeting (SORT) molecules or developing novel targeting ligands, such as Ly6C antibody specific for liver sinusoidal endothelial cells, to achieve precise delivery of different cell subsets in the liver. For the microenvironment of chronic liver disease (such as fibrosis barrier), the design of enzyme-responsive LNP can improve the penetration efficiency. In addition, the combination of saRNA technology with LNP is expected to solve the challenge of frequent drug administration in the treatment of chronic diseases. In the field of combination therapy, the strategy of LNP co-delivery of CRISPR components and immunomodulatory mRNAs, such as IL-21, may provide a new paradigm for functional cure of HBV and HCC immunotherapy. In terms of clinical translation, AI-driven formulation screening and freeze-drying process development of LNP will accelerate accessibility, while personalized evaluation models based on organoids and organ-on-a-chip are expected to shorten the research and development cycle.