Deposition of Antibody Modified Upconversion Nanoparticles on Glass by a Laser-Assisted Method to Improve the Performance of Cell Culture

A suitable surface is vital for maintaining or even promoting cells' function and communication. Recently, studies show that nanostructured coatings could have a potential in improving cell adhesion. However, it hardly minimizes the contamination by using traditional solution-coating technology. Matrix-assisted pulsed laser evaporation (MAPLE) technique is a contamination-free process and demonstrates an efficient process to deposit biopolymer without damaging their backbone on the surface of various substrates. Here, upconversion nanoparticles (NaGdF4: Yb3+, Er3+) with/without immunoglobulin G (IgG) modification were produced by a one-pot synthesis method. The average size of the upconversion nanoparticles (UCNPs) is 50 ± 8 nm. IgG bio-conjugated on the surface of UCNPs can be directly observed by transmission electron microscope (TEM). MAPLE system utilizing a Nd:YAG laser (λ = 532 nm, ν = 10 Hz) is applied to deposit UCNPs with/without IgG modification on the glass bottom of culture dish. In addition, the behaviors of human umbilical vein endothelial cells (HUVECs) cultured on the culture dishes coated with UCNPs with/without IgG have been studied as compared to the control sample, glass coated with gelatin. No toxic effect is imposed on cells. The results of this work indicate that the deposition of UCNPs with/without antibody by the MAPLE technique could enhance the adhesion and proliferation of cells.

Intercalation of Bi2O3/Bi2S3 nanoparticles into highly expanded MoS2 nanosheets for greatly enhanced gas sensing performance at room temperature

Synthesizing a gas sensor based on heterostructured nanomaterials (NMs) via a controllable morphology by a facile hydrothermal method is an area of frontier research. In the present work, we designed a facile strategy to synthesize a controllable morphology and composition for three component heterojunctions (MoS₂-Bi₂O₃-Bi₂S₃) NMs using different hydrothermal reaction times. The Bi₂S₃ easily form as an intermediate phase due to the strong interaction of the Bi₂O₃ with MoS₂ nanosheets (NSs). The as fabricated heterojunctions MB-5 NMs exhibited a sensitive response to NO_x gas (R_a/R_g = 10.7 at 50 ppm), with an ultra-fast response time of only 1 s (s) at room temperature (RT) in air. The detection limit was predicted to be as low as 50 ppb. This sensational behaviour of the sensor reveals the outstanding morphological structure and synergistic effect of the MoS₂ NSs with Bi₂O₃ nanoparticles (NPs), which was realized by the flow of electrons across MoS₂-Bi₂O₃-Bi₂S₃ interfaces through band energy alignment.