Fabrication of resistive-type humidity sensors based on either hybrid polymers of polypyrrole(PPy)–ZnO nanoparticles or their nanocomposites is reported. Hybrid polymers with different ZnO content (14, 19, 32 and 46%) were synthesized via oxidative polymerization of free pyrrole monomer with pyrrole moieties covalently bonded on the surface of ZnO nanoparticles. Moreover, nanocomposites consisting of the above mentioned ZnO content were prepared by efficient mixing of PPy homopolymer with ZnO nanoparticles. The products were characterized via FTIR, TGA, XRD and SEM techniques. The surfaces of the sensing films were characterized with AFM showing uniform and continuous films. Sensors with the highest sensitivity were obtained using hybrid polymers with higher ZnO content and lower particle sizes. Compared to ZnO–PPy nanocomposite sensors, the hybrid polymer sensors showed higher sensitivity and more linear response (R² = 0.9879–0.9921) over a wide range of relative humidity (11–75%) at room temperature. It was concluded that the covalent bonding of PPy chains with ZnO nanoparticles in a hybrid polymer results in a p–n junction which, in contrast to the one in nanocomposites has a chemical nature. The p–n junction with such a nature enhances the charge transfer between PPy and ZnO nanoparticles in hybrid polymers compared to nanocomposite samples, and hence, imparts higher sensitivity to hybrid polymer based sensors. Investigation of the response–recovery behavior of sensors in 180 seconds of response period indicated a high repeatability and recovery time of 60 seconds without a noticeable hysteresis.

Among the various nano/biomaterials used in cancer treatment, the beauty and benefits of DNA nanocomposites are outstanding. The specificity and programmability of the base pairing of DNA strands, together with their ability to conjugate with different types of functionalities have realized unsurpassed potential for the production of two- and three-dimensional nano-sized structures in any shape, size, surface chemistry and functionality. This review aims to provide an insight into the diversity of static DNA nanodevices, including DNA origami, DNA polyhedra, DNA origami arrays and bioreactors, DNA nanoswitch, DNA nanoflower, hydrogel and dendrimer as young but promising platforms for cancer theranostics. The utility and potential of the individual formats in biomedical science and especially in cancer therapy will be discussed.