Correction: The potential role of borophene as a radiosensitizer in boron neutron capture therapy (BNCT) and particle therapy (PT)

Abstract

Correction for ‘The potential role of borophene as a radiosensitizer in boron neutron capture therapy (BNCT) and particle therapy (PT)’ by Pengyuan Qi et al., Biomater. Sci., 2020, 8, 2778–2785, DOI: 10.1039/D0BM00318B.

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The authors apologize for the errors in Fig. S2 in the original manuscript (ESI). The correct version has been provided in the updated ESI.

In addition, the authors would like to correct several statements related to Fig. 1 in the original manuscript to avoid confusion:

1. Page 2, Left Column, Lines 26–28: “...the SEM image of the bulk boron powder indicates an average particle size of 2 μm (lateral) as well as its amorphous nature.” should read “...the SEM image indicates the irregular shape from a macroscopic point of view.”

2. Page 2, Right Column, Lines 12–13: “...large quantities of randomly oriented layer boron sheets were indeed formed.” should read “...the layered boron sheets are indeed formed.”

3. Page 2, Right Column, Lines 21–22: “...the size of borophene is relatively uniform, consistent with the AFM result (ESI Fig. S1).” should read “...the size of borophene appears to stay in the range between 50 nm and 200 nm. The AFM (Fig. S1) results demonstrate that the thickness of borophene is ∼8 nm.”

One question raised by a number of readers drew our attention, that is, whether the material the authors synthesized could be named “borophene”, or whether the name “borophene sheet” is more appropriate. The authors consider this a debatable issue. More discussion of the preparation of borophene using liquid phase exfoliation can be found in Pranay Ranjan et al., Adv. Mater., 2019, 31, 1900353, which the authors regret not including in the original manuscript.

For completeness, the authors would like to take this opportunity to provide more information with regard to sample preparation and characterization.

The raw elemental boron powder (99%, Art no. B835561) was bought from Shanghai Macklin Biochemical Co., Ltd.

Preparation of boron sheets: 150 mg bulk boron powder were added into 150 ml ethylene glycol (EG) solvent to form a suspension with a concentration of 1 mg ml⁻¹. The suspension was first treated using the ball milling technique at 350 rpm for 48 h. To obtain the layered boron sheets, the solution was centrifuged at a lower (5000 rpm) speed for 15 min, and subsequently centrifuged at a higher speed (13 000 rpm) for 60 min. Finally, the sample was collected by drying under vacuum at 50 °C for 12 h.

Preparation of borophene: Dried boron sheets were re-dispersed in 4 mL of deionized water (DIW) solution. A bath sonication process was conducted at a constant temperature of 10 °C for 48 h (ultrasonication frequency: 40 kHz), to obtain a colloid solution.

Characterization of borophene: The details of the characterization (SEM, TEM, XPS, AFM, and EELS) are below:

The microstructure was characterized by scanning electron microscopy (SEM, S-4800, Hitachi, Japan), HRTEM (TEM, JEM 2010 FEF, JEOL, Japan), and AFM (Dimension Edge, Bruker, America). The elemental compositions were analyzed via X-ray photoelectron spectroscopy (XPS, ESCALAB 250Xi, Thermo Fisher, USA) with a monochromatic Al Kα X-ray beam (225 W, 15 Ma, 15 kV).

For the SEM experiment, the raw sample of boron was mounted on aluminum stubs using conductive glue.

For the TEM experiment, the sample was dispersed onto a super-thin carbon film using 95% ethanol, and air-dried before imaging (200 kV).

For the XPS experiment, the sample was dispersed in 95% ethanol and then dropped on the surface of a silicon wafer (2 mm by 2 mm), and air-dried.

For the AFM experiment, AFM samples were prepared by dropping the borophene dispersions onto a mica sheet followed by Ar drying.

The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

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Footnote

† These two authors contributed equally to this work.

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