Drug delivery’s quest for polymers: Where are the frontiers?

Since the legendary 1964 article of Folkman and Long entitled “The use of silicone rubber as a carrier for prolonged drug therapy” the role of polymers in controlled drug delivery has come a long way. Today it is evident that polymers play a crucial if not the prime role in this field. The latest boost owes to the interest in drug delivery for the purpose of tissue engineering in regenerative medicine. The focus of this commentary is on a selection of general and personal observations that are characteristic for the current state of polymer therapeutics and carriers. It briefly highlights selected examples for the long march of synthetic polymer–drug conjugates from bench to bedside, comments on the ambivalence of selected polymers as inert excipients versus biological response modifiers, and on the yet unsolved dilemma of cationic polymers for the delivery of nucleic acid therapeutics. Further subjects are the complex design of multifunctional polymeric carriers including recent concepts towards functional supramolecular polymers, as well as observations on stimuli-sensitive polymers and the currently ongoing trend towards natural and naturally-derived biopolymers. The final topic is the discovery and early development of a novel type of biodegradable polyesters for parenteral use. Altogether, it is not the basic and applied research in polymer therapeutics and carriers, but the translational process that is the key hurdle to proceed towards an authoritative approval of new polymer therapeutics and carriers.     

Lipofectamine^TM2000介导pIRES2-DsRed2-Hath1、pIRES2-EGFP-NT3质粒对HEK293T细胞共转染的实验研究

目的检测真核表达质粒载体pIRES2-EGFP—NT3、pIRES2-DsRed2-Hath 1在阳离子脂质体介导下对HEK293T细胞的共转染情况。方法分别提取含有目的基因NT3的真核表达质粒载体pIRES2-EGFP—NT3和含有目的基因Hath 1的真核表达质粒载体pIRES2-DsRed2-Hath 1，在阳离子脂质体Lipofectamine^TM2000介导下将其共转染HEK293T细胞，转染后24h，通过Confocal显微镜观察HEK293T细胞的转染情况和转染效率。结果pIRES2-EGFP-NT3和pIRES2-DsRed2．Hath 1能有效转染并共转染HEK293T细胞，其转染率pIPES2-EGFP-NT3为23．79％（157／660）；pIRES2-DsRed2-Hath 1为8．03％（53／660）；共转染率为3．64％（24／660）。结论pIRES2-EGFP—NT3和pIRES2-DsRed2-Hath 1在阳离子脂质体介导下对HEK293T细胞的共转染成功为NT3和Hath 1基因共转染耳蜗的实验奠定基础。