Microgravity as a means to incorporate HepG2 aggregates in polysaccharide–protein hybrid scaffold

Abstract

Tissue culture under microgravity provides a venue which promotes cell-cell association while avoiding the detrimental effects of high shear stress. Hepatocytes cultured on carriers or entrapped within matrices under simulated microgravity conditions showed improved cell function and proliferation. In the present study, a new approach was adopted where a non-cell adherent scaffold was incorporated with hepatospheroids (HepG2) under microgravity. Gum arabic (GA) was cross-linked with gelatin (GA-Gel) and collagen (GA-Col) to prepare non-cell adherent scaffolds. Microgravity experiments with GA-Gel and GA-Col indicated that GA-Col is a better substrate compared to GA-Gel. Microgravity experiments of GA-Col scaffolds with HepG2 cells confirmed that the non-adherent surface with porous architecture can incorporate hepatocyte spheroids and maintain liver specific functions. Albumin and urea synthesis of hepatocytes was sustained up to 6 days under microgravity conditions in the presence of GA-Col scaffold. This new approach of using non-cell adherent matrix and microgravity environment for developing biological substitutes will be beneficial in tissue engineering, bioartificial liver devices and in vitro safety assessment of drugs.

Comparison of Gold Nanoparticles Deposition Methods and Their Influence on Electrochemical and Adsorption Properties of Titanium Dioxide Nanotubes

“…Dissociation of the electrolyte of gold salt solution [AuCl 4 ] − was presented by Equation (1). As shown in the Equation (2) and according to the data presented by [ 21 ], Au 3+ can be reduced to Au 0 and obtain electrons. [AuCl 4 ] − ↔ Au 3+ + 4Cl − Au 3+ + 3e ↔ Au 0 …”

“…The reduction of Au 3+ concentration causes the concentration gradient between titanium dioxide nanotubes and the solution. On the other hand, the occurrence of the concentration gradient causes the moves of Au 3+ ions into TNTs and the formation of many reduced Au 0 crystals [ 21 ]. Higher current densities occurring at the places of TNTs contact cause the deposition of AuNPs in these places [ 21 , 22 ].…”

“…After the gold nanoparticles deposition process, the values of the open-circuit potential of the samples increases compared to bare TNTs. It is a result of the inherent inertness of gold and the fact that it is not uniformly distributed on the surface of TNTs [ 21 ]. According to the theory of electrostatic binding, the aim is to obtain a positively charged surface of TNTs, which will facilitate the binding of negatively charged proteins [ 33 ].…”

“…Photoreduction is a long-lasting and difficult to precisely control parameters technique [ 18 ]. In turn, the use of cyclic voltammetry [ 19 , 20 ] and chronoamperometry [ 21 ] greatly simplify the process of modifying the TNTs platform. The authors’ earlier work showed the possibility of controlling the AuNPs morphologic parameters (diameter in the range of 20.3 ± 2.9 to 182.3 ± 51.7 nm) by choosing parameters of the CV process [ 22 ].…”

Effect of Flavonoid-Coated Gold Nanoparticles on Bacterial Colonization in Mice Organs

“…Various nanocarrier systems were documented to be effective against E. Faecalis .These include gold nanorods for phototherapy [ 1 ], vancomycin bound biogenic AuNPs [ 19 ], calcium hydroxide NPs [ 20 ], chitosan NPs [ 21 ], Ag–Ca–Si mesoporous NPs [ 22 ], silver NPs [ 23 ], and polysaccharide-maghemite composite NPs [ 24 ]. However, these studies are focused on in-vitro antibacterial activity.…”