Abstract: The present invention belongs to the technical field of gene therapy, and particularly relates to a series of lipid compounds as well as a lipid carrier, nucleic acid lipid nanoparticle composition and pharmaceutical preparation containing the same. A compound having a structure of a formula (I) provided by the present invention can be used for preparing a lipid carrier together with other lipid compounds, and exhibits pH response, and the entrapment efficiency to a nucleic acid drug is high, which greatly improves in-vivo delivery efficiency of the nucleic acid drug; and furthermore, a lipid compound with a specific structure can be chosen as a lipid carrier based on an organ in which the nucleic acid drug needs to be enriched, having a good market application prospect.

Abstract: The present disclosure relates to a recombinant nucleic acid molecule of the transcriptional circular RNA and its application in protein expression. Specifically, the present disclosure relates to a recombinant nucleic acid molecule of the transcriptional circular RNA, recombinant expression vector, pre-circularized RNA, circular RNA, recombinant host cell, pharmaceutical composition and protein preparing method. The transcription product of the recombinant nucleic acid molecule in this present disclosure is a circular RNA which containing specific IRES element. IRES element can increase the protein expression level of circular RNA in eukaryotic cells, achieve efficient and persistent expression of protein. It has important application value in many fields like: Preparation of mRNA infectious disease vaccines, therapeutic mRNA tumor vaccines, mRNA-based dendritic cell tumor vaccines, mRNA-based gene therapy, mRNA-based chimeric antigen receptor T cell therapy, and protein supplement therapy.