title: A Selective and Purification-Free Strategy for Labeling Adherent Cells with Inorganic Nanoparticles.
abstract: Cellular labeling with inorganic nanoparticles such as magnetic iron oxide nanoparticles, quantum dots, and fluorescent silica nanoparticles is an important method for the noninvasive visualization of cells using various imaging modalities. Currently, this is mainly achieved through the incubation of cultured cells with the nanoparticles that eventually reach the intracellular compartment through specific or nonspecific internalization. This classic method is advantageous in terms of simplicity and convenience, but it suffers from issues such as difficulties in fully removing free nanoparticles (suspended in solution) and the lack of selectivity on cell types. This article reports an innovative strategy for the specific labeling of adherent cells without the concern of freely suspended nanoparticles. This method relies on a nanocomposite film that is prepared by homogeneously dispersing nanoparticles within a biodegradable polymeric film. When adherent cells are seeded on the film, they adhere, spread, and filtrate into the film through the micropores formed during the film fabrication. The pre-embedded nanoparticles are thus internalized by the cells during this infiltration process. As an example, fluorescent silica nanoparticles were homogeneously distributed within a polycaprolactone film by utilizing cryomilling and heat pressing. Upon incubation within physiological buffer, no silica nanoparticles were released from the nanocomposite film even after 20 d of incubation. However, when adherent cells (e.g., human mesenchymal stem cells) were grown on the film, they became fluorescent after 3 d, which suggests internalization of silica nanoparticles by cells. In comparison, the suspension cells (e.g., monocytes) in the medium remained nonfluorescent no matter whether there was the presence of adherent cells or not. This strategy eventually allowed the selective and concomitant labeling of mesenchymal stem cells during their harvest from bone marrow aspiration.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457.|Key Laboratory for Organic Electronics & Information Displays (KLOEID), Institute of Advanced Materials (IAM), National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Gao
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457.
authors.forename: Jing
authors.initials: J
authors.lastname: Lim
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457.
authors.forename: David Chen Loong
authors.initials: DC
authors.lastname: Yeo
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Liao
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457.
authors.forename: Malin
authors.initials: M
authors.lastname: Lans
authors.affiliation: Hybrid Silica Technologies , Cambridge, Massachusetts 02139, United States.
authors.forename: Yaqi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457.
authors.forename: Swee-Hin
authors.initials: SH
authors.lastname: Teoh
authors.affiliation: National Dental Centre of Singapore , Second Hospital Avenue, Singapore 168938.
authors.forename: Bee Tin
authors.initials: BT
authors.lastname: Goh
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University , 70 Nanyang Drive, Singapore 637457.|NTU-Northwestern Institute for Nanomedicine, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798.
authors.forename: Chenjie
authors.initials: C
authors.lastname: Xu
mesh_terms: D002448:Cell Adhesion; D002469:Cell Separation / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry*; D018922:HL-60 Cells; D006801:Humans; D008567:Membranes, Artificial; D053758:Nanoparticles / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013194:Staining and Labeling / Q000379:methods; D020298:U937 Cells
chemical_list: D005456:Fluorescent Dyes; D008567:Membranes, Artificial; D011091:Polyesters; C016240:polycaprolactone; D012822:Silicon Dioxide
keywords: adherent cells; bone marrow aspiration; mesenchymal stem cells; nanocomposite polymeric film; nanoparticles; selective cell labeling