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Printing amphotericin B on microneedles using matrix-assisted pulsed laser evaporation

than matrix-assisted pulsed laser evaporation targets matrix-assisted pulsed laser evaporation-modified
containing lower drug concentrations. microneedle arrays successfully delivered amphotericin
Energy-dispersive X-ray spectra of the matrix- B to the agar plates, inhibiting the growth of Candida
assisted pulsed laser evaporation-modified microneedles albicans. The results for matrix-assisted pulsed laser
indicated the presence of carbon, oxygen, and sulfur; evaporation-deposited amphotericin B coatings on
the presence of sulfur is associated with the dimethyl silicon wafer substrates and glass substrates also showed
sulfoxide solvent that was used to prepare the matrix- concentration-dependent activity, with coatings deposited
assisted pulsed laser evaporation target. Other elements from a 2080 mg/mL target showing higher antifungal
(e.g., elements with known toxicity) were not observed activity than coatings deposited from a 1040 mg/mL
on the surface of the matrix-assisted pulsed laser target (Table 4).
evaporation-modified microneedles. The unmodified The skin penetration properties of the microneedle
microneedles contained carbon and oxygen; sulfur or arrays were evaluated using methylene blue dye and
other elements were not identified on the surfaces of the human skin. Methylene blue was used to visualize the
unmodified microneedles. site of microneedle penetration. Figure 6 shows human
The modified agar diffusion assay result for the skin after the application of the microneedle array, re-
unmodified polyglycolic acid microneedle array (which moval of the microneedle array, and application of
served as a control) shows no inhibition of Candida methylene blue. The presence of methylene blue spots
albicans growth. In comparison, the amphotericin B in the microneedle array-treated skin indicates that the
(1040 mg/mL) matrix-assisted pulsed laser evaporation- microneedle arrays are effective in penetrating human
deposited microneedle array and the amphotericin B skin.
(2080 mg/mL) matrix-assisted pulsed laser evaporation- 4. Conclusions
deposited microneedle array show 100% inhibition
of Candida albicans in zones that measured 11 mm The antifungal drug amphotericin B was deposited onto
and 18 mm, respectively (Figure 5). The results are the surfaces of polyglycolic acid microneedles using
comparable to previously reported results, which matrix-assisted pulsed laser evaporation. Solutions
were obtained from paper disks that were loaded with con taining polyvinylpyrrolidone and amphotericin B
10 µg of amphotericin B [38] . The results indicate that in dimethyl sulfoxide were frozen in liquid nitrogen;
the solidified solutions were used as targets for matrix-
assisted pulsed laser evaporation. Unlike the unmodified
a b mi croneedles, the matrix-assisted pulsed laser
evaporation-coated microneedles exhibited antifungal
activity against the yeast Candida albicans. The zones
of inhibition for the uncoated microneedle array, the
amphotericin B (1040 mg/mL) matrix-assisted pulsed
laser evaporation-deposited microneedle array, and the

c d Table 4. Disk diffusion assay data obtained from uncoated and
matrix-assisted pulsed laser evaporation-coated surfaces. Data
were obtained for an uncoated polyglycolic acid microneedle,
a matrix-assisted pulsed laser evaporation-coated microneedle
from deposition with the AmfB(260) target (amphotericin B
1040 mg/mL + 1% polyvinylpyrrolidone), and a matrix-assisted
pulsed laser evaporation-coated microneedle from deposition
with the AmfB(520) target (amphotericin B 2080 mg/mL + 1%
polyvinylpyrrolidone). Disk diffusion assay data obtained from
matrix-assisted pulsed laser evaporation-coated glass and silicon
Figure 5. Modified disk diffusion assay result with Candida wafers are also provided.
albicans for an uncoated polyglycolic microneedle array (a),
a matrix-assisted pulsed laser evaporation-coated microneedle Sample type Zone of inhibition (mm)
array from deposition with the AmfB(260) target (amphotericin
B 1040 mg/mL + 1% polyvinylpyrrolidone (noted as AB (260)), Control 0
and a matrix-assisted pulsed laser evaporation-coated microneedle Amf B(260) 11
array from deposition with the AmfB(520) target (amphotericin
B 2080 mg/mL + 1% polyvinylpyrrolidone) (noted as AB (520)) Amf B(520) 18
(b). Zones of growth inhibition were noted surrounding the Amf B(260) Glass 19
matrix-assisted pulsed laser evaporation-coated microneedle
arrays. In addition, zones of inhibition were noted surrounding Amf B(520) Glass 24
pieces of glass (c) and silicon (d) wafer that were coated with the Amf B(260) Si 25
AmfB(260) target and the AmfB(520) target using matrix-assisted
pulsed laser evaporation. Amf B(520) Si 31

154 International Journal of Bioprinting (2017)–Volume 3, Issue 2