title: pH-sensitive nanomicelles for controlled and efficient drug delivery to human colorectal carcinoma LoVo cells.
abstract: BACKGROUND
  The triblock copolymers PEG-P(Asp-DIP)-P(Lys-Ca) (PEALCa) of polyethylene glycol (PEG), poly(N-(N',N'-diisopropylaminoethyl) aspartamide) (P(Asp-DIP)), and poly (lysine-cholic acid) (P(Lys-Ca)) were synthesized as a pH-sensitive drug delivery system. In neutral aqueous environment such as physiological environment, PEALCa can self-assemble into stable vesicles with a size around 50-60 nm, avoid uptake by the reticuloendothelial system (RES), and encase the drug in the core. However, the PEALCa micelles disassemble and release drug rapidly in acidic environment that resembles lysosomal compartments.
  
  
  RESULTS
  The anticancer drug Paclitaxel (PTX) and hydrophilic superparamagnetic iron oxide (SPIO) were encapsulated inside the core of the PEALCa micelles and used for potential cancer therapy. Drug release study revealed that PTX in the micelles was released faster at pH 5.0 than at pH 7.4. Cell culture studies showed that the PTX-SPIO-PEALCa micelle was effectively internalized by human colon carcinoma cell line (LoVo cells), and PTX could be embedded inside lysosomal compartments. Moreover, the human colorectal carcinoma (CRC) LoVo cells delivery effect was verified in vivo by magnetic resonance imaging (MRI) and histology analysis. Consequently effective suppression of CRC LoVo cell growth was evaluated.
  
  
  CONCLUSIONS
  These results indicated that the PTX-SPION-loaded pH-sensitive micelles were a promising MRI-visible drug release system for colorectal cancer therapy.
authors: Department of Radiology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
authors: Shi-Ting
authors: ST
authors: Feng
authors: PCFM Lab of Ministry of Education, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, China.
authors: Jingguo
authors: J
authors: Li
authors: Department of Radiology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
authors: Yanji
authors: Y
authors: Luo
authors: Department of Medical Ultrasonic, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors: Tinghui
authors: T
authors: Yin
authors: Department of Radiology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
authors: Huasong
authors: H
authors: Cai
authors: PCFM Lab of Ministry of Education, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, China.
authors: Yong
authors: Y
authors: Wang
authors: Department of Radiology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
authors: Zhi
authors: Z
authors: Dong
authors: PCFM Lab of Ministry of Education, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, China.
authors: Xintao
authors: X
authors: Shuai
authors: Department of Radiology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
authors: Zi-Ping
authors: ZP
authors: Li
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic; D015179:Colorectal Neoplasms / Q000473:pathology*; D004337:Drug Carriers / Q000737:chemistry* / Q000633:toxicity; D005290:Ferric Compounds / Q000737:chemistry; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008422:Materials Testing; D051379:Mice; D008823:Micelles; D053758:Nanoparticles / Q000737:chemistry*; D017239:Paclitaxel / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D004337:Drug Carriers; D005290:Ferric Compounds; D008823:Micelles; D011108:Polymers; C000499:ferric oxide; D017239:Paclitaxel