3.2. Biocompatibility of composite materials and
FACHB-314
We studied the effects of nanoparticles of rGO-TiO2 on
the biomass and nitrate consumption of FACHB-314 and its cell
structure or subcellular structure to determine the biocompatibility of
the material with FACHB-314 . rGO-TiO2 composite
nanoparticles were added to the FACHB-314 culture medium to
determine the change in dry cell weight and the residual nitrate content
in the culture medium. FACHB-314 cultured without nanoparticles
was used as a control group. It can be observed from Figure 5 that the
dry cell weight of FACHB-314 added with composite photocatalytic
nanomaterials changes relative to the blank group and the remaining
nitrate content in the culture medium. Among them, Figure 5(a) shows the
growth trend of the two groups of FACHB-314 and gradually
increases. On day 9, the weight of FACHB-314 stem cells cultured
on the composite photocatalytic nanomaterials reached 1.24g/L, and the
blank group reached 1.36g/L. Compared with the blank group, the
experimental group only changed by 8.8%. Then, the residual nitrate
content in the two sets of culture media was determined. The result is
shown in Figure 5(b). The residual nitrate content also tends to be
consistent. Based on this, we concluded that, compared with the blank
group, nanoparticle rGO-TiO2 will not adversely affect
the two indicators of FACHB-314 biomass and remaining nitrate
content.
Figure 6 shows a photomicrograph of the effect of
rGO-TiO2 and TiO2 nanoparticles on the
morphology of FACHB-314 cells. Figure 6(a), (c), (e) shows the
morphology of the three types of microalgae on the first day, (a) is a
control group of FACHB-314 under an optical microscope, (c) isFACHB-314 with TiO2 nanoparticles added under an
optical microscope, and (e) is a control group of FACHB-314 under
an optical microscope. FACHB-314 and rGO-TiO2nanoparticles. The morphology of these three kinds of FACHB-314is normal, showing unidirectional growth and left-handed spiral
arrangement. Unlike the control group, the FACHB-314 filaments of
the two experimental groups are all attached with nanoparticles, but
they have no effect on the morphology and structure of FACHB-314 .
On the sixth day, the subcellular structures of the three microalgae are
as follows: Figure 6 (b) is the control group FACHB-314 under the
transmission electron microscope (d) is the FACHB-314 doped with
nanoparticle TiO2 under the transmission electron
microscope, and (f) is the transmission electron microscope.FACHB-314 doped with nanoparticles of rGO-TiO2under the electron microscope. By observing the microstructure of the
three groups of FACHB-314 , it is found that the vegetative cells
undergo two divisions during unidirectional growth, and there are
obvious transfers on the transverse wall. The trichomes are wrapped in a
thin sheath, and there are obvious structures at the crossing walls (Li
et al., 2017; Lupatini et al., 2017). In the trichomes of the
experimental group, especially under the treatment of titanium dioxide
nanoparticles, the transverse wall structure of the trichomes became
difficult to distinguish, the morphological abnormalities ofFACHB-314 were clearly visible, and the cell membrane and
transverse wall were twisted. The horizontal wall structure in the
middle disappeared. The cell shape of the control group showed a flat
surface, and the cell membrane was not damaged. The mixing ofFACHB-314 and composite photocatalytic nanoparticles
rGO-TiO2 has a certain effect on the cell morphology ofFACHB-314 . For example, the horizontal wall is opaque, the cell
wall is wrinkled, etc., but it still maintains the basic morphological
characteristics and will not cause obvious damage to the sexual
structure. The above results indicate that rGO-TiO2nanoparticles have good biocompatibility for the growth ofFACHB-314 .