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Zheng, et al.
antitumor and antibacterial ability, and Ag release developed SLS system was used to build the 3D scaffold
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spectrum. Besides, we explored the potential mechanisms layer by layer. SLS could meet the personalized needs
of antitumor and antibacterial stents (Figure 1II). of bone implantation due to the controllable external
shape and pore size of the scaffold [27-32] . Typically, a layer
2. Experimental methods of 0.1 mm thick powder were spread by the roller at a
2.1. Materials constant speed; then, the powders were selectively fused
by the laser beam under the control of the programmed
PGA was supplied by from Shenzhen Polymtek pattern; subsequently, the powder bed was lowered
Biomaterial Co. Ltd. (Shenzhen, China). The average by 0.1 mm and the powder was respread, the sintering
molecular weight of PGA was 100 kDa. MoS NSs were process was repeated until the scaffold was complete; the
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supplied by Nanjing XFNano Materials Tech Co. Ltd. primary processing parameters of the scaffold preparation
(Jiangsu, China), with diameter in the range of 0.2 – 5 μm were hatch distance (0.1 mm), laser power (2.7 W), and
and more than 90% monolayer rate. Silver nitrate (AgNO ) scan speed (300 mm/s). The sintered scaffold of pure
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was purchased from Sinopharm Chemical Reagent Co., PGA powder was named PGA, the sintered scaffold was
Ltd. Tris-HCl and dopamine hydrochloride as well as named MoS /PGA, PMoS /PGA, and Ag@PMoS /PGA
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other reagents of analytical grade were purchased from after mixing MoS , PMoS , and Ag@PMoS NSs with
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Sigma (Shanghai, China). All the above raw materials PGA powder, respectively.
were used as received.
2.4. Analysis and characterization
2.2. Preparation of Ag@PMoS nanosheets
2 The morphology of Ag@PMoS , PMoS , and MoS was
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Figure 1I shows the preparation of silver by in situ observed by transmission electron microscopic (TEM)
reduction on MoS NSs. In general, 0.04 g MoS NSs was (Morgagni 268D, FEI, USA). The chemical structure of
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added to 100 mL TRIS-HCl buffer (10 mM, pH = 8.5) Ag@PMoS , PMoS , and MoS was analyzed by Fourier-
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and ultrasonic stirred for 2 h. Then, 0.2 g dopamine transform infrared spectroscopy. The morphology and
hydrochloride was added and stirred vigorously at room elemental composition distribution of Ag@PMoS ,
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temperature for 12 h. Black precipitate was separated PMoS , and MoS and composite scaffolds were observed
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and collected at 6000 rpm for 10 min, and washed with by scanning electron microscopy (SEM) (EVO LS10,
anhydrous ethanol for 5 times. To generate Ag NPs in situ Zeiss, Germany) equipped with energy-dispersive
on PDA surface, the products obtained in the above spectroscopy (EDS) (XFlash 6130, Bruker, Germany).
experiments were dispersed into 100 mL ethanol under The chemical composition of Ag@PMoS , PMoS , and
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ultrasonic conditions, then 2 mL 0.12 M AgNO solution MoS was evaluated by X-ray photoelectron spectroscopy
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was added into the reaction system. After mixing well (XPS) (ESCALAB 250, Thermo Scientific, UK). The
and standing for 24 h, the supernatant was removed and crystal structure of Ag@PMoS , PMoS , and MoS was
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the precipitate was resuspended with 100 mL ethanol. observed by X-ray diffractometer (XRD) (Empyrean-100,
The mixture was added to a 250 mL oil bath and stirred PANalytical, Netherlands). The Ag release spectrum of
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with magnetic force. When the temperature rose to 80℃, composite scaffolds in deionized water was quantitative
30 mL NaH PO ·H O (14.8 mg/mL) ethanol solution was analyzed by inductively coupled plasma optical emission
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added to the above mixture, reacting for 20 min. Then, spectrometer (Optima 8300, Perkin Elmer, USA).
the products were cooled at room temperature for 12 h
and washed 6 times with anhydrous ethanol. Finally, the 2.5. Photothermal performance and
products were dried in a vacuum oven at 60℃ for 24 h. photothermal stability of composite scaffolds
2.3. Scaffold preparation The prepared scaffolds were immersed in pure water, and
the PGA, MoS /PGA, PMoS /PGA, and Ag@PMoS /
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As we know, PGA is a kind of non-toxic and PGA scaffolds were irradiated by a NIR laser generator.
non-immunogenicity biomaterial with excellent We designed pure water as the background group because
biodegradability and biocompatibility, which has been water can absorb a certain amount of NIR energy . Under
[33]
approved by the Food and Drug Administration for the same laser power density (1 W/cm ), the composite
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human clinical applications. Herein, PGA was used as scaffold was irradiated with 808 nm laser for about
the matrix material to prepare the composite scaffold. 750 s, and the corresponding solution temperature data
Specifically, the 0.1 g nanometer sample and 9.9 g PGA were recorded in real time to evaluate the photothermal
powder were dispersed into a beaker containing 30 mL performance of the composite scaffolds. In addition, the
anhydrous ethanol for ultrasonic stirring for 30 min. The photothermal stability of the Ag@PMoS /PGA scaffold
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composite powder was then obtained through filtering, was evaluated by four switching cycles under NIR
drying, grinding, and other processes. Finally, the self- irradiation.
International Journal of Bioprinting (2022)–Volume 8, Issue 3 113
Please cite this article as: Zheng L, Zhong Y, He T, et al., 2022, A Codispersed Nanosystem of Silver-anchored MoS Enhances Antibacterial
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and Antitumor Properties of Selective Laser Sintered Scaffolds, Int J Bioprint, 8(3):0025. http://doi.org/10.18063/ijb.v8i3.0025