Gold nanoparticles forged by nanosecond-pulsed laser ablation in liquid have shown a striking ability to kill cancer cells in laboratory tests, and a new study reports that the liquid medium used during synthesis—double distilled water, sodium hydroxide solution, or cell culture medium—measurably changes both the particles’ physical characteristics and their cytotoxic potency. The research, published in Gold Bulletin, synthesized gold nanoparticles in three different liquid environments and then subjected them to a battery of structural, chemical, morphological, and optical characterization techniques before testing them against a mouse liver cancer cell line.
The synthesis method itself is physically elegant. A pulsed Nd:YAG laser, operating at either 532 or 1064 nanometers, was focused through a lens onto a gold plate of 99.99 percent purity submerged in each liquid. When the laser beam strikes the target, it removes material from the surface and promotes the formation of nanoparticles within a vapor pocket surrounded by the liquid. At sufficiently high laser fluence, the room-temperature solid surface layer of the target melts, and overheating transforms the surrounding liquid medium into a gaseous state. The high-pressure vapor then reacts with the molten layer on the target surface, creating nanoparticles that disperse into the surrounding liquid. The researchers selected 300 pulses, a 10-nanosecond pulse duration, and a repetition rate of 6 hertz for all three solutions, keeping the laser beam’s travel length through the liquid as short as possible to prevent the beam’s energy from being absorbed by the solution itself.
The choice of this physical approach over conventional chemical synthesis is deliberate. Chemical techniques can produce stable gold nanoparticles with plasmon absorption peaks in the visible to near-infrared wavelength region, but they rely on reducing agents and stabilizing surfactants that generate potentially dangerous byproducts. Laser ablation in liquid, by contrast, is valued for its ease of use and its potential to produce chemically pure nanoparticles without those additives. Because the method has not been extensively researched across different liquid media, the team set out to determine how the synthesis medium alters the size and surface shape of the resulting gold particles—a question they consider crucial for applications involving photothermal treatment.
X-ray diffraction confirmed that the nanoparticles were crystalline gold with a face-centered cubic structure. Diffraction peaks appeared at characteristic angles corresponding to the (111), (200), (220), and (311) crystal planes, and the researchers applied the Scherrer formula to determine crystallite size from the patterns. The average crystallite sizes calculated this way were 11.4 nanometers for particles made in double distilled water, 19.7 nanometers for those made in sodium hydroxide, and 8.8 nanometers for those made in the cell culture medium DMEM. Notably, the paper’s conclusions section states that atomic force microscopy and transmission electron microscopy demonstrated the presence of crystallinity and the purity of the gold compound, with XRD verifying the cubic-centered, crystalline nature of the particles.
Transmission electron microscopy provided direct images of particle morphology and dispersion across all three media. The particles were nanosized and approximately spherical regardless of the liquid used, but their dimensions differed substantially. The smallest particles emerged from the DMEM medium, with an average diameter of about 5 nanometers, while the largest came from the sodium hydroxide medium, averaging roughly 25 nanometers. Atomic force microscopy added a complementary topographical picture: two-dimensional images revealed semi-spherical gold nanoparticles, and the analysis yielded average particle diameters of approximately 48.6 nanometers for Au-DDDW, 63.8 nanometers for Au-NaOH, and 88.8 nanometers for Au-DMEM, along with corresponding grain area measurements of 2484.9, 1241.8, and 7335.8 square nanometers respectively.
Optical measurements corroborated successful nanoparticle formation. Ultraviolet-visible spectroscopy showed a large absorption peak between roughly 500 and 550 nanometers, the signature of localized surface plasmon resonance in gold nanoparticles—the phenomenon that gives colloidal gold its red or purple color near 530 nanometers. The absorption maxima were measured at approximately 515 nanometers for Au-DMEM, 524 nanometers for Au-NaOH, and 521 nanometers for Au-DDDW, with spectra recorded at room temperature across visible wavelengths from 400 to 900 nanometers. Fourier transform infrared spectroscopy, scanning the region from 4000 to 400 inverse centimeters, identified absorption bands associated with O–H stretching, C≡C and C≡N stretching, C–O stretching, and C–H bands, and found that the compounds were essentially identical across all three nanoparticle media regardless of particle size, with only small shifts in peak positions.
The biological testing focused on Hepa 1–6 mouse liver cancer cells obtained from the National Cell Bank of Iran, grown in RPMI-1640 medium supplemented with 10 percent fetal bovine serum and antibiotics at 37 degrees Celsius. The researchers used the MTT cell viability assay, a standard colorimetric test, to quantify cell growth and survival. Cells were seeded into 96-well plates, treated for 24 hours, and then exposed to the MTT solution, with the concentration causing 50 percent cell death—the IC50 value—determined from dose-response curves. The experiment included an untreated control group alongside three treatment groups receiving nanoparticles synthesized in double distilled water, sodium hydroxide, or DMEM.
The cytotoxicity results revealed meaningful differences among the three nanoparticle preparations. Gold nanoparticles made in double distilled water showed medium cytotoxicity, with an IC50 of 53.95 micrograms per milliliter. Particles made in sodium hydroxide were the least potent, requiring 74.38 micrograms per milliliter to reach the same effect. The DMEM-synthesized particles were the most toxic to the cancer cells, with an IC50 of just 35.48 micrograms per milliliter, and at a concentration of 12.5 micrograms per milliliter the DMEM nanoparticles were more toxic than those made in sodium hydroxide. According to the study’s statistical analysis, performed with one-way ANOVA using SigmaPlot software, the test compounds demonstrated significant cytotoxic potential against the Hepa 1–6 mouse cell lines when compared to a standard drug used in the study. The data also showed that cell viability declines as nanoparticle concentration rises.
The researchers attribute the enhanced activity of the DMEM-prepared particles to protein adsorption. Connecting gold nanoparticles with biological fluids is described as a crucial step in facilitating endocytosis—the process by which cancer cells engulf the particles—and in this work that binding was achieved by using DMEM, a cell culture medium, as the synthesis medium itself. The adsorption of protein compounds from DMEM onto the nanoparticle surfaces caused localized shifts in the absorption maxima, and the resulting particles were larger than those prepared in the other two liquids. The paper also discusses the general mechanisms by which metallic nanomaterials can be hazardous, noting that toxicity is linked to the production of reactive oxygen species and resulting oxidative stress, while also citing work suggesting gold nanoparticles can act as antioxidants by scavenging free radicals and boosting antioxidant enzyme activity.
The authors conclude that gold nanoparticles produced by nanosecond-pulsed laser ablation in these three liquid media show encouraging anticancer effects in vitro and could be candidates for additional nanotherapeutic applications, while explicitly cautioning that more research is required to evaluate the in vivo anticancer effects of these laser-synthesized particles. It is worth emphasizing the scope of the current evidence: these are in vitro results from a single mouse cancer cell line exposed for 24 hours, not findings from animal models or human patients, and the reported cytotoxicity reflects cell killing in a laboratory dish rather than any demonstrated therapeutic outcome. Physical investigations in the study did show that laser settings and the surrounding medium influence nanoparticle size and concentration, and that the particles’ biological impact depends on both size and concentration—with the effect growing with size among particles made in double distilled water but diminishing with size among those made in DMEM. Within those limits, the study offers a concrete demonstration that a solvent-free physical synthesis route can tune both the material properties and the laboratory cytotoxic behavior of gold nanoparticles simply by changing the liquid in which they are born.
Subject of Research: Laser ablation synthesis of gold nanoparticles in different liquid media and their in vitro cytotoxicity against a mouse liver cancer cell line
Article Title: Nanosecond-pulsed laser ablation synthesis of gold nanoparticles in DDDW, NaOH, and DMEM liquid media: unveiling of microstructural morphological, chemical, optical, and structural characterizations and cytotoxic evaluation of enhanced anticancer efficacy
Article References: Khamees, E. J., Rashid, E. Y., Al-Kufaishi, Z. H. J., Mohammed, K. A., Al-Taee, R. A. M., Sharma, S., Kalyani, T., Sharma, M., Kulshreshta, A., Kumar, A., & Ramaswamy, K. (2025). Nanosecond-pulsed laser ablation synthesis of gold nanoparticles in DDDW, NaOH, and DMEM liquid media: unveiling of microstructural morphological, chemical, optical, and structural characterizations and cytotoxic evaluation of enhanced anticancer efficacy. Gold Bulletin, 58(1), Article 10. https://doi.org/10.1007/s13404-025-00363-z
Image Credits: AI Generated
DOI: 10.1007/s13404-025-00363-z
Keywords: gold nanoparticles, laser ablation in liquid, nanosecond-pulsed laser, DMEM, cytotoxicity, MTT assay, Hepa 1-6, X-ray diffraction, transmission electron microscopy, surface plasmon resonance, nanomedicine, in vitro study
News Source: Nathaniel Bowman. (October 29, 2026). Laser-Made Gold Nanoparticles Kill Cancer Cells in the Lab, With the Right Liquid Making All the Difference. Scienmag.
