Nucleic acid drugs are nucleic acids themselves or closely related compounds, including natural nucleotides and chemically modified nucleotides, that can be used to treat disease [
94-
96]. Nucleic acid drugs have the advantages of simple design, short research and development cycle, strong targeting specificity, wide therapeutic fields and long-term performance [
97], showing great potential in the treatment of genetic diseases, viral infections, tumors and other fields, and are expected to become the third class of drugs after small molecule drugs and antibody drugs [
98]. Ma
et al. designed a star polymer-siRNA nanoparticles infused with aerosols to deliver siRNA to the lungs, inhibiting the expression of two genes βⅢ-tubulin and Polo-like kinase 1 (PLK1). slowing the aggressive growth of tumors (
Fig. 3A) [
99]. The synthesis of core-crosslinked Miktoarm star polymer nanoparticles (star nanoparticles) was achieved through reversible addition-fragmentation chain-transfer (RAFT) polymerization of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and poly[oligo(ethylene glycol)methyl ether methacrylate] (POEGMA) [
100]. Subsequent distribution of biological experiments in mice,
in vitro fluorescence imaging of representative organs of mice administered intravenously or by aerosol showed different results, with intravenously administered mice nanoparticles mainly distributed in the kidneys and liver, while aerosol administered mice nanoparticles mostly accumulated in the lungs, and no nanoparticles were found in the kidneys, liver, and spleen at any point in time (
Fig. 3B). In an orthotopic mouse lung tumor model, the delivery of siPLK1 using star polymers also achieved very significant therapeutic effects (
Fig. 3,
Fig. 3). Poly(β-amino esters) (PBAEs) are a class of biodegradable polymers that can be synthesized using various simple chemical methods. The cationic nature of PBAEs enables them to effectively complex with nucleic acids, forming nanoparticles. Additionally, PBAEs exhibit lung-targeting capabilities, making them promising candidates for pulmonary therapies [
101]. Le
et al. prepared PBAE-lipid nanoparticles by combining PBAEs with dioleoylphosphatidylethanolamine (DOPE) and DMG-PEG in a specific ratio, dissolving the mixture in ethanol. They then vigorously mixed these nanoparticles with mRNA encoding bevacizumab in an acidic aqueous phase, resulting in PBAE lipid nanoparticles containing mRNA. After intravenous administration, these nanoparticles preferentially target the lungs, where they are taken up by pulmonary endothelial cells. Following escape from endosomal-lysosomal compartments, the mRNA is released inside the cells, where it encodes antibodies with bevacizumab functionality, inhibiting the production of vascular endothelial growth factor (VEGF) and consequently suppressing tumor growth (
Fig. 4) [
102]. Additionally, Rotolo
et al. conducted a series of modifications on PBAE, such as multifunctional amines, amino alcohols, and amino thiols. The resulting various polymers were evaluated for mRNA delivery treatment in the lungs, successfully screening out polymers capable of effectively delivering mRNA to the lungs of different animals. This makes future inhalable nucleic acid therapy for lung treatment a possibility [
103]. Huang
et al. proposed a nanoparticle co-delivery system of gefitinib (Gef) and YAP-siRNA, utilizing block and dendritic polymers, to address the issue of NSCLC resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) (
Fig. 5) [
104]. These nanoparticles were effectively internalized by NSCLC cells in both CDX and PDX models and were able to escape from lysosomes/endosomes. In the reductive cellular environment, they released Gef and YAP-siRNA. Gef inhibited the EGFR signaling pathway, while YAP-siRNA suppressed the activation of the EGFR bypass signaling pathway, achieving effective tumor growth inhibition. Additionally, the strategy could be combined with photodynamic therapy, inducing apoptosis by downregulating hypoxia-inducible factor-1 alpha (HIF-1α) [
104]. Gou
et al. used silk fibroin (SF) and gelatin as raw materials, employing gelatin to induce liquid-liquid phase separation of SF, and developed suitable GSC nanoparticles (
Fig. 6) [
105]. These nanoparticles possess broad-spectrum drug delivery capabilities and, when administered through aerosolization, exhibit matrix metalloproteinase-9 (MMP-9) responsiveness in cells. They also demonstrate certain immunomodulatory properties, such as promoting the polarization of macrophages to the M1 phenotype and the maturation of dendritic cells, thereby enhancing immune responses and showing significant therapeutic effects [
101].