Thermoresponsive copolymer nanofilms for controlling cell adhesion, growth, and detachment.
ABSTRACT This study reports the development and use of a novel thermoresponsive polymeric nanofilm for controlling cell adhesion and growth at 37 °C, and then cell detachment for cell recovery by subsequent temperature drop to the ambient temperature, without enzymatic cleavage or mechanical scraping. A copolymer, poly(N-isopropylacrylamide-co-hydroxypropyl methacrylate-co-3-(trimethoxysilyl)propyl methacrylate) (abbreviated PNIPAAm copolymer), was synthesized by free radical polymerization. The thermoresponses of the copolymer in aqueous solution were demonstrated by dynamic light scattering (DLS) through detecting the sensitive changes of copolymer aggregation against temperature. The DLS measurements revealed the lower critical solution temperature (LCST) at approximately 30 °C. The PNIPAAm film stability and robustness was provided through silyl cross-linking within the film and with the hydroxyl groups on the substrate surface. Film thickness, stability, and reversibility with respect to temperature switches were examined by spectroscopic ellipsometry (SE), atomic force microscopy (AFM), and contact angle measurements. The results confirmed the high extent of thermosensitivity and structural restoration based on the alterations of film thickness and surface wettability. The effective control of adhesion, growth, and detachment of HeLa and HEK293 cells demonstrated the physical controllability and cellular compatibility of the copolymer nanofilms. These PNIPAAm copolymer nanofilms could open up a convenient interfacial mediation for cell film production and cell expansion by nonenzymatic and nonmechanical cell recovery.
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ABSTRACT: Rare cells already have become established indicators for disease diagnosis, to help track prognosis, and in developing personalized therapy. Numerous techniques have been developed to effectively and specifically detect and sort rare cells and cell isolation techniques have gained much attention among researchers in last few decades. Recent developments in nanotechnologies and microfluidics have been used with great promise towards these goals. The research emphasis has also shifted from simple detection with microfluidic devices to comprehensive isolation, collection and subsequent analysis with integrated and automated systems. The first challenge in post-isolation analysis is cell detachment from substrates, while keeping cells viable and unperturbed. In this review, various methods used for cell detachments are discussed. For effective cell sorting, the detachment is identified as critical criteria for selecting substrates and methods.Biotechnology advances 08/2013; · 8.25 Impact Factor