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Lou, et al.
reliable, and durable antibacterial coatings is increasingly of the cathode, a variety of patterns can be obtained. The
urgent. metal plating layer deposited in the previous step can
Nickel is widely used in coatings to protect metal be used as the substrate for the next deposited layer. As
substrates from corrosion due to its good corrosion the number of reciprocating scans of the deposition area
resistance and wear resistance . Antibacterial coatings increases, the coating grows layer by layer, forming a
[11]
with excellent comprehensive properties are expected three-dimensional geometric entity. The high efficiency
to be obtained through the preparation of nickel- mass transfer of the jet between the electrodes makes the
based composite coatings. As a derivative of graphene, jet electrodeposition have the advantage of high limit
graphene oxide (GO) is obtained by oxidation of graphite current, which is conducive to the improvement of the
under acidic conditions . Due to its unique physical and coating deposition efficiency and the enhancement of
[12]
chemical properties, GO has important research value in the bonding force with the substrate [38,39] . By adjusting
biology, energy, medicine, sensors, and other fields [13-15] . the composition of the plating bath, multiple composite
Abundant oxygen-containing functional groups are coatings can be prepared. The flowing plating bath will
distributed on the edge (hydroxyl and carboxyl) and base promote the dispersion of the second phase in the bath
surface (epoxy) of GO sheets, endowing GO with excellent and improve the uniformity of the composite coating, and
hydrophilicity, and dispersibility . Since GO was first no additional post-process is required after the coating is
[16]
reported to exhibit antibacterial ability in 2010 , many prepared. Therefore, jet electrodeposition is widely used
[17]
studies on the antibacterial mechanism and application of for the preparation of composite coatings [38,40] .
GO have begun to be carried out. The physical damage However, the agglomeration of GO in the plating
of the sharp edges of GO, the effect of oxidative stress, bath has always been a challenge for the preparation of
and wrapping or trapping of bacterial membranes by the GO composite coating. The agglomerates of GO in the
thin film of GO are considered to be the three mainstream plating bath will have a great negative impact on the
antibacterial mechanisms of GO [18-20] . In addition, preparation of the coating. It is also common that GO
theories regarding the extraction of lipid bilayers and the cannot be introduced into the coating due to agglomeration
interference of signal proteins have been reported [21,22] . (Figure S1). To solve the problem of the difficulty
Although the antibacterial mechanism of GO is still of the deposition of GO on the coating, the magnetic
controversial, the outstanding antibacterial performance field-assisted scanning electrodeposition technique was
of GO has been accepted, and its applications are being applied to the fabrication of GO-loaded nickel (GNC).
expanded. Some methods for the preparation of GO Magnetic field-assisted jet electrodeposition is a new
coatings have been reported, such as cold spraying, thin type of process for preparing composite coatings, and
evaporation, chemical vapor deposition, electrophoretic our group has reported the preparation of Nickel/Silicon
deposition, and chemical grafting [23-25] . Carbide (Ni-SiC) composite coating by magnetic field-
Additive manufacturing (AM), defined as a process assisted jet electrodeposition[41]. The introduction of
to build three-dimensional (3D) objects by joining magnetic field and ferromagnetic particles promoted the
materials layer by layer, has been used in automotive, deposition of GO on the coating. In this work, GO is no
aerospace, printed electronics, and healthcare [26-30] . Inkjet longer independently dispersed into the plating bath as the
printing and electrohydrodynamic jetting are widely second phase, but is dispersed into the plating bath together
used in printed electronics and biological printing with with ferromagnetic nickel particles (Nip). The sheet-like
their excellent dimensional accuracy [31-34] . Compared GO adsorbs on the surface of the Nip to form GO-loaded
with the traditional coating process, AM can shorten nickel particles. During the cathode deposition process,
the production cycle of coating preparation, does not the permanent magnet under the cathode provides a stable
require assembly or mold preparation, and consumes less magnetic field to capture the Nip. As the nickel coating
energy . Laser melting deposition is an efficient method grows, these GO-loaded particles are bound and fixed
[35]
that can effectively enhance the fusion of powder and by the nickel coating, and eventually become part of the
matrix and is widely used in the preparation of ceramic- coating. In this work, the GNC was prepared by magnetic
reinforced metal-based composite coatings [27,36] . As a field-assisted scanning jet electrodeposition, and then the
kind of AM technology, local electrochemical deposition antibacterial activity and the antibacterial process of the
technology can realize the directional deposition of metal composite coating were studied.
ions layer by layer to print metal parts . In the process
[37]
of jet electrodeposition, the pumped plating bath forms a 2. Materials and methods
conductive jet between the cathode and anode under the 2.1. Materials
restriction of the nozzle, and the deposition is realized
in the contact area between the jet and the cathode. By GO used in the experiment is commercial few-layer GO
adjusting the position of the deposition area on the surface purchased from Guoheng Technology Co., Ltd (China).

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