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Article

Engineering Biocompatible Glutathione-Capped Cu2ZnSnS4 Quantum Dots Toward Integrated Photothermal and Photodynamic Effects

by
Ning Lu
2,
Yufeng Zang
3 and
Lingshuai Kong
1,*
1
Institute of Eco-Environmental Forensics, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
2
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
3
School of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, China
*
Author to whom correspondence should be addressed.
Materials 2026, 19(4), 763; https://doi.org/10.3390/ma19040763
Submission received: 26 December 2025 / Revised: 9 February 2026 / Accepted: 10 February 2026 / Published: 15 February 2026
(This article belongs to the Special Issue Advanced Nanostructured Materials in Biomedical Applications: Synthesis and Characterization)
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Abstract

Ultrasmall near-infrared (NIR)-responsive quantum dots (QDs) are highly promising for deep-tissue phototherapy but often face challenges with biocompatibility and clearance. In this study, Cu2ZnSnS4 quantum dots (CZTS QDs) were synthesized via a non-injection method and surface-functionalized with glutathione (GSH) to create water-dispersible and biocompatible CZTS@GSH QDs. Comprehensive characterization using XRD, TEM, DLS, XPS, and UV-Vis spectroscopy confirmed a sphalerite-type ZnS crystal structure, an average hydrodynamic diameter of ~6.2 nm, and a band gap of 1.47 eV (843.5 nm). The CZTS@GSH QDs demonstrated effective photothermal conversion under 808 nm laser irradiation, achieving a temperature increase sufficient for photothermal therapy (PTT). Furthermore, using a DPBF assay, the QDs were shown to generate singlet oxygen, confirming their photodynamic therapy (PDT) capability. Owing to their ultrasmall size, strong NIR absorption, and demonstrated dual PTT/PDT functions, the CZTS@GSH QDs are established as a nanoplatform with potential for combined cancer treatment.

Graphical Abstract

1. Introduction

Copper-based chalcogenides represent a significant class of multifunctional materials with considerable promise for biomedical applications [1,2,3,4]. Among these, multinary copper chalcogenide nanocrystals are of particular interest due to a suite of advantageous properties, including low thermal conductivity, cost-effectiveness, tunable band gaps, high charge carrier concentrations, excellent intrinsic functional characteristics, and stoichiometric versatility [3,5,6]. Notably, strong localized surface plasmon resonances (LSPRs) in the near-infrared (NIR) region have been demonstrated in materials such as Cu2−xS [7], CuInS2 [8], and Cu3BiS3 [9]. This composition-dependent LSPR behavior stands as a key advantage over noble metals, as it enables precise tuning of optical properties through modifications in composition, crystal structure, and morphology. Consequently, these materials hold great potential for applications in photocatalysis, optoelectronics, and biomedical imaging [10,11]. To date, numerous nanoparticles with absorption in the 700–950 nm window have been explored as theranostic agents. However, a major challenge for their clinical translation is the propensity of many nanoparticles to accumulate in vital organs, which can lead to acute toxicity, carcinogenicity, and chronic inflammatory responses [12,13]. While promising, the efficient clearance of nanoparticles from the body remains a significant hurdle. Renal clearance, a primary excretion pathway, requires that materials exhibit a hydrodynamic diameter typically below 15 nm to facilitate rapid elimination from the systemic circulation [14]. Therefore, the rational design of ultrasmall nanoparticles with controlled size and surface properties is crucial for balancing therapeutic efficacy with biosafety.
Among various quaternary chalcogenides, Cu2ZnSnS4 (CZTS) has emerged as a particularly promising candidate for photothermal therapy (PTT) [15,16,17,18,19]. Its composition of earth-abundant elements (Cu, Zn, Sn, S) is advantageous from a sustainability standpoint. While the potential toxicity of ionic tin species requires consideration, the Sn atoms in CZTS are incorporated into a stable crystalline sulfide lattice, which significantly limits their bioavailability and leaching potential. CZTS exhibits outstanding optoelectronic properties, including a large absorption coefficient (104 cm−1) and a significant wide band gap (1.5 eV), which is highly suitable for NIR-mediated applications [20]. A notable feature of such quaternary chalcogenides is the ability to engineer their function, for instance, by adjusting elemental ratios or introducing dopants, without significantly altering their physical dimensions, thereby decoupling functional tuning from size control critical for clearance [10,21]. Importantly, the biodistribution, pharmacokinetics, and clearance profiles of therapeutic agents are predominantly governed by their size and surface characteristics [22,23,24]. An ideal agent based on copper chalcogenides could be designed not only to induce localized hyperthermia under NIR irradiation but also to generate reactive oxygen species (ROS) for concurrent photodynamic therapy (PDT), enabling synergistic tumor ablation [1,25,26,27]. Although CZTS quantum dots (QDs) have been synthesized typically via hot-injection methods [28,29], the preparation of phase-pure, ultrasmall, and water-dispersible CZTS QDs with a well-defined surface remains challenging. This difficulty stems from the inherent complexity in precisely controlling the composition, phase, size and morphology of such multinary materials, which are critical for biological efficacy and potential clearance.
Based on the discussion above, the fundamental scientific problem persists: the rational design of a single-component, biocompatible nanoplatform that seamlessly integrates efficient NIR photothermal conversion with high photodynamic activity, while overcoming the synthetic hurdles associated with precise phase control and ultrasmall size regulation in multinary chalcogenides to meet the requirements for bio-logical applications. In this work, we report a non-injection synthesis of ultrasmall, monodisperse Cu2ZnSnS4 quantum dots (CZTS QDs) followed by surface functionalization with glutathione (GSH) to achieve water dispersibility and enhanced biocompatibility. We systematically demonstrate that these QDs not only serve as efficient photothermal agents but also generate singlet oxygen under 808 nm laser irradiation, enabling integrated photothermal and photodynamic effects.

2. Experimental Section

2.1. Synthesis of CZTS@GSH Quantum Dots

Cu2ZnSnS4 quantum dots capped with glutathione (CZTS@GSH) QDs were synthesized via a modified solution-based method. In a typical procedure, CuCl2·2H2O (1 mmol), SnCl2·2H2O (0.5 mmol), and ZnCl2 (0.5 mmol) were dissolved in 50 mL of absolute ethanol under vigorous magnetic stirring. Subsequently, thiourea (CH4N2S, 2 mmol) was added to the homogeneous solution. The ethanol solvent was then removed under reduced pressure at 45 °C. The resulting precursor mixture was dispersed in 10 mL of oleylamine and heated to 220 °C for 5 min under a nitrogen atmosphere. After being allowed to cool naturally to room temperature, the crude product was collected by centrifugation and washed repeatedly with ethanol.
To render the QDs water-dispersible and biocompatible, a ligand exchange process was employed [30]. Specifically, 100 mg of the as-synthesized oleylamine-capped QDs, 3 mL of 3-mercaptopropionic acid (MPA) (as a transient ligand), and 250 mg of reduced glutathione (GSH) were added to 5 mL of N, N-dimethylformamide (DMF). The mixture was heated to 130 °C under nitrogen for 15 min. Upon cooling to room temperature, the final product (CZTS@GSH QDs) was isolated by centrifugation, washed with ethanol, and dried in a vacuum oven at 60 °C overnight.

2.2. Photothermal and Photodynamic Performance Measurements

The singlet oxygen (1O2) generation capability was assessed using 1,3-diphenylisobenzofuran (DPBF) as a chemical probe. Briefly, DPBF (20 mg/L) and CZTS@GSH QDs (10 mg/L) were added to ethanol (20 mL) in dark under the stirring condition for 1 h. The mixture was then irradiated with the 808 nm laser (0.5 W/cm2). The degradation of DPBF, indicative of 1O2 production, was monitored by tracking the decrease in its characteristic absorption peak at 410 nm using UV-Vis spectroscopy at regular intervals. Control experiments confirmed that DPBF alone was stable under 808 nm laser irradiation for the duration of the experiment. The NIR laser system was equipped with a commercially available 808 nm diode laser (BWT, Beijing, China). Photoluminescence (PL) spectra were recorded on a Horiba Fluorolog 3 spectrofluorometer (JobinYvon, France) between 1100 and 1500 nm using a liquid-N2-cooled InGaAs detector, an excitation wavelength of 530 nm. NIR laser light (0.5 W/cm2) was delivered through a quartz cuvette containing the CZTS@GSH QDs to study the temperature change mediated by CZTS@GSH QDs. Pure water was used as a control to establish the baseline temperature response under identical irradiation conditions. The temperature change was monitored in real-time using a calibrated infrared thermal imaging camera (S6-a, IRS/FOTRIC, Shanghai, China). The biocompatibility was tested against 4T1 murine breast cancer cells. 4T1 cells maintained at 37 °C (under 5% CO2) were seeded in 96-well plates at a density of 5 × 103 cells per well. Then, 4T1 cells were treated with different concentrations of CZTS@GSH QDs (200, 150, 100 or 50 ppm), and cultured for 12, 24 or 36 h. Cell viability was determined using a standard MTT assay protocol.

2.3. Materials Characterization

The crystal structure of the QDs was analyzed by X-ray diffraction (XRD) on a Bruker D8 Advance diffractometer (Karlsruhe, Germany) using Cu Kα radiation (λ = 1.5418 Å). Morphological and structural details were obtained using high-resolution transmission electron microscopy (HRTEM) on a JEOL JEM-2010 instrument (Tokyo, Japan) operating at 200 kV. The elemental composition and surface chemistry were investigated by X-ray photoelectron spectroscopy (XPS) on an ESCALAB 250Xi spectrometer (Waltham, MA, USA) with a monochromatic Mg Kα X-ray source. The hydrodynamic diameter and zeta potential of the QDs in aqueous dispersion were measured by dynamic light scattering (DLS) using a Malvern Zetasizer Nano ZS (Mavern, UK). Optical absorption spectra across the UV-Vis-NIR range were recorded on a Hitachi U-4100 spectrophotometer (Tokyo, Japan).

3. Results and Discussion

3.1. Morphology and Size Analysis

The CZTS QDs were initially synthesized via a non-injection method, yielding oleylamine-capped nanoparticles readily dispersible in nonpolar organic solvents. Transmission electron microscopy (TEM) analysis (Figure 1a) demonstrates that the as-prepared QDs possess a quasi-spherical morphology with high monodispersity. Statistical analysis of the TEM images indicates an average particle diameter of 3.2 ± 0.4 nm (Figure 1b). Furthermore, the high-resolution TEM (HRTEM) image (Figure 1c, inset) reveals well-defined lattice fringes with a measured interplanar spacing of 0.311 nm, which corresponds to the (111) crystallographic planes of the cubic CZTS phase.
Following ligand exchange with glutathione (GSH), the water-dispersible CZTS@GSH QDs were obtained. Dynamic light scattering (DLS) measurements (Figure 1d) indicated a hydrodynamic diameter of less than 10 nm, with an average size of ~6.2 nm. The slight increase from the TEM-derived core size (3.2 nm) to the DLS-measured hydrodynamic diameter is attributed to the presence of the hydrophilic GSH capping layer and the associated solvation shell. This hydrodynamic diameter (<10 nm) falls within the size range often associated with potential renal clearance, which is a key consideration for clinical translation [31]. However, definitive clearance pathways require future in vivo pharmacokinetic and biodistribution studies, as elimination is also governed by surface chemistry and in vivo stability.

3.2. Structural and Compositional Characterization

The crystal structure of the synthesized CZTS@GSH QDs was confirmed by X-ray diffraction (XRD). As shown in Figure 2, the XRD pattern exhibits three broad diffraction peaks at 2θ values of 28.8°, 47.8°, and 56.5°, which can be indexed to the (111), (220), and (311) planes of the cation-disordered cubic sphalerite structure (space group F-43m). This structure is isostructural with cubic ZnS; therefore, the peak positions are consistent with the reference pattern for cubic ZnS (JCPDS No. 05-0566), which is commonly used for indexing the diffraction patterns of CZTS nanocrystals [32,33]. No detectable impurity phases, such as binary or ternary sulfides (e.g., Cu2S, ZnS, SnS2), were observed, confirming the formation of phase-pure CZTS. The peak broadening is consistent with the nanocrystalline nature of the material. The calculated lattice constant (a = 0.563 nm) further verifies the cubic structure. This cation-disordered cubic phase is commonly observed in CZTS nanocrystals and can be attributed to the similar ionic radii of Cu+, Sn4+, and Zn2+ cations, which occupy the tetrahedral sites within the sulfur sublattice in a random distribution. The apparent crystallite sizes were determined by Rietveld refinement/whole profile fitting (WPF) using Jade 6 software, yielding an average particle size of approximately 5 nm for CZTS. XRD-derived average particle sizes are larger than those obtained by TEM because the XRD technique is sensitive to the volume-weighted average crystallite size, whereas TEM provides a direct measurement of individual particle dimensions.
X-ray photoelectron spectroscopy (XPS) was employed to analyze the surface elemental composition and chemical states. The survey spectrum (Figure S1) shows predominant signals of Cu, Zn, Sn, and S. High-resolution spectra (Figure 3a–d) reveal the following: the Cu 2p spectrum shows peaks at binding energies of 932.6 eV (2p3/2) and 952.7 eV (2p1/2) (spin–orbit splitting of 20.1 eV) without significant shake-up satellite features, characteristic of Cu(I) [34]. The Zn 2p peaks at 1023.0 eV (2p3/2) and 1046.0 eV (2p1/2) correspond to Zn(II) [35]. The Sn 3d spectrum exhibits peaks at 486.3 eV (3d5/2) and 494.7 eV (3d3/2), indicative of Sn(IV) [36]. The S 2p spectrum can be deconvoluted into a doublet at 161.2 eV (2p3/2) and 162.4 eV (2p1/2), assigned to S2− in metal sulfides [37]. These results are consistent with the expected oxidation states in CZTS and match well with reported literature values.
The optical properties of the CZTS@GSH QDs were investigated by UV-Vis-NIR absorption spectroscopy. As shown in Figure 4a, the QDs exhibit a broad absorption band extending from the visible into the near-infrared (NIR) region, which is advantageous for deep-tissue photothermal applications [38]. The band gap of the nanocrystals was estimated by the following equation, αhν = A (hν − Eg)m/2, where A is a constant, α is the absorption coefficient, hν is the photon energy, Eg is the band gap and m = 1 for a direct transition [39]. Eg can be obtained by extrapolating the linear region of the plot of (αhν)2 versus energy (hν). The UV–Vis spectrum and the Tauc plot of the CZTS were shown in Figure 4b. It can be observed that the band gap of CZTS was found to be 1.47 eV from the intercepts of the extrapolation lines and energy axis at the band gap energy (Eg). This value corresponds to an absorption onset near 843.5 nm. The CZTS QDs exhibit absorption extending into the NIR region, including at 808 nm, which is attributed to their band-edge and sub-gap states, enabling their use as an effective agent for both PTT and PDT under 808 nm laser irradiation.

3.3. Photodynamic Performance

The capacity of CZTS@GSH QDs to function as a photosensitizer for photodynamic therapy (PDT) was evaluated by investigating their ability to generate singlet oxygen (1O2) under near-infrared (NIR) irradiation. Singlet oxygen production was first monitored using the chemical probe 1,3-diphenylisobenzofuran (DPBF), which undergoes an irreversible reaction with 1O2, resulting in a quantifiable decrease in its characteristic absorbance at 410 nm [40]. As depicted in Figure 5a, the absorption intensity of DPBF at 410 nm decreased progressively upon irradiation with an 808 nm laser (0.5 W/cm2) in the presence of CZTS@GSH QDs (0.2 g/L), indicating continuous 1O2 generation. In a control experiment, DPBF alone exhibited negligible photodegradation under identical irradiation conditions, confirming that the observed signal decay is specifically mediated by the QDs. The normalized time-dependent decay of the DPBF absorbance (Figure 5b) further underscores the role of CZTS@GSH QDs as an effective NIR-activated photosensitizer.
To provide direct spectroscopic evidence of 1O2 generation, we employed near-infrared photoluminescence (NIR PL) spectroscopy. Singlet oxygen undergoes radiative decay with a characteristic emission band centered around 1270 nm, which serves as a direct signature for its detection and quantum yield determination [41]. The NIR PL spectra of CZTS@GSH QDs and the standard photosensitizer Rose Bengal (RB, ΦRB = 0.86 in ethanol) were acquired under 530 nm excitation (Figure 6). The integrated luminescence intensity of the 1O2 emission band (1200–1350 nm) was used to estimate the singlet oxygen quantum yield (Φ) of the QDs relative to RB, according to the equation ΦCZTS@GSH = ΦRB × (ICZTS@GSH/IRB), where I denote the integrated emission intensity. Based on the measured integrated intensities (ICZTS@GSH ≈ 36,749, IRB ≈ 65,810), ΦCZTS@GSH was calculated to be approximately 0.48. This value indicates a substantial 1O2 generation efficiency, comparable to or exceeding that of many reported photosensitizers [42]. The slight spectral shift observed between the 1O2 emission profiles of CZTS@GSH QDs and RB (Figure 6) is attributed to differences in the local microenvironment surrounding the generated 1O2, a phenomenon commonly noted in luminescence-based assays [40,41].

3.4. Photothermal Performance

The photothermal conversion capability, essential for photothermal therapy (PTT), was systematically investigated. Aqueous dispersions of CZTS@GSH QDs at various concentrations (0 to 1.0 g/L) were irradiated with an 808 nm laser at a power density of 0.5 W/cm2 (Figure 7). The temperature increase in pure water was less than 2 °C. In contrast, the QD dispersions showed rapid and concentration-dependent temperature elevations. For instance, a dispersion at 1.0 g/L reached a temperature increase (ΔT) of 22.6 °C within 500 s, while a concentration of 0.2 g/L resulted in a ΔT of 11.0 °C. The heating rate was initially rapid and gradually slowed, likely due to increased heat loss to the environment at higher temperatures, indicating efficient photothermal conversion [43]. To quantitatively evaluate the photothermal performance, the photothermal conversion efficiency (η) was calculated according to the method reported by Brian et al. [44,45]. The calculated η value for CZTS@GSH QDs was 20%. This efficiency is higher than that of commercial Au nanoshells (13%) reported in the literature and comparable to that of Cu2−xSe nanocrystals (22%) [44], demonstrating the competitive photothermal conversion capability of our CZTS@GSH QDs.

3.5. Cytotoxicity Assay In Vitro

The biocompatibility and potential dark toxicity of the CZTS@GSH QDs were evaluated using 4T1 murine breast cancer cells via a standard MTT assay [46,47]. As shown in Figure 8, cells incubated with varying concentrations of CZTS@GSH QDs (0–200 mg/L) for up to 36 h maintained high viability (>89% even at the highest concentration and longest incubation time). The MTT assay demonstrates low dark cytotoxicity of the CZTS@GSH QDs against 4T1 cells over 36 h, which is a necessary initial condition for their application as phototherapeutic agents. However, a complete biocompatibility and safety profile for clinical translation requires consideration of factors beyond acute in vitro cell viability. As highlighted in recent reviews on the biological fate of advanced nanomaterials [48], the long-term safety of copper-based chalcogenides depends on their stability, ion release kinetics, potential to induce oxidative stress, biodegradation pathways, and interactions with immune components. While the glutathione (GSH) coating is designed to enhance stability and biocompatibility, future studies must systematically evaluate these aspects. Specifically, in vivo biodistribution, pharmacokinetics, and long-term toxicity studies will be essential to assess potential accumulation in organs, chronic inflammatory responses, and clearance mechanisms. Furthermore, investigating the generation of reactive oxygen species (ROS) under physiological conditions, both in the dark and upon irradiation, will provide a more nuanced understanding of the nanomaterial’s interaction with cellular redox balance. This expanded framework will allow for a more balanced and critical assessment of the translational potential of the CZTS@GSH QD platform. The separate demonstration of photothermal conversion and singlet oxygen generation establishes the foundational dual functionality of the CZTS@GSH QDs. Future cell-based studies under NIR irradiation are required to explicitly evaluate the combined and potentially synergistic therapeutic efficacy of these dual effects.

4. Conclusions

In summary, we have developed a synthetic strategy combining a non-injection approach with a subsequent aqueous phase transfer to fabricate water-dispersible, glutathione-capped Cu2ZnSnS4 quantum dots (CZTS@GSH QDs). DLS analysis revealed a mean hydrodynamic diameter of approximately 6.2 nm for the synthesized CZTS@GSH QDs. This small size is a favorable starting point for potential renal clearance, although this requires validation through future in vivo studies. XRD and XPS studies verify the formation of phase-pure, cubic sphalerite-type CZTS with the characteristic cation-disordered structure and expected elemental oxidation states. The CZTS QDs exhibit a direct band gap of 1.47 eV, corresponding to NIR absorption. The CZTS@GSH QDs demonstrate dual functionality in vitro: efficient photothermal conversion under 808 nm laser irradiation and the ability to generate cytotoxic singlet oxygen. Coupled with their demonstrated biocompatibility under dark conditions, the properties of these CZTS@GSH QDs warrant future investigation for cancer theranostics.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/ma19040763/s1, Figure S1. High-resolution XPS spectra of survey for CZTS.

Author Contributions

N.L., writing—original draft, methodology, visualization, and investigation; Y.Z., methodology and validation; L.K., supervision, visualization, formal analysis, investigation, writing—review & editing, and funding acquisition. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the Shandong Provincial Natural Science Foundation (2023HWYQ-041) and Youth Innovation Team Development Project of Shandong universities (No. 2023KJ297).

Data Availability Statement

The original contributions presented in this study are included in the article/Supplementary Material. Further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no competing interests.

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Materials 19 00763 g001
Figure 1. (a) TEM images of CZTS QDs. (b) High-resolution TEM images of CZTS QDs. (c) Size distribution of CZTS QDs. (d) The hydrodynamic diameter of the CZTS@GSH QDs measured by DLS.
Figure 1. (a) TEM images of CZTS QDs. (b) High-resolution TEM images of CZTS QDs. (c) Size distribution of CZTS QDs. (d) The hydrodynamic diameter of the CZTS@GSH QDs measured by DLS.
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Figure 2. XRD pattern of the synthesized CZTS@GSH QDs. The reference pattern for cubic sphalerite ZnS (JCPDS No. 05-0566) is provided for comparison.
Figure 2. XRD pattern of the synthesized CZTS@GSH QDs. The reference pattern for cubic sphalerite ZnS (JCPDS No. 05-0566) is provided for comparison.
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Figure 3. High-resolution XPS characterization of CZTS QDs (a) Cu 2p; (b) Zn 2p; (c) Sn 3d; and (d) S 2p.
Figure 3. High-resolution XPS characterization of CZTS QDs (a) Cu 2p; (b) Zn 2p; (c) Sn 3d; and (d) S 2p.
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Figure 4. (a) UV-Vis-NIR absorption spectrum of CZTS@GSH QDs. (b) Corresponding Tauc plot ((αhν)2 vs. hν) for direct band gap determination.
Figure 4. (a) UV-Vis-NIR absorption spectrum of CZTS@GSH QDs. (b) Corresponding Tauc plot ((αhν)2 vs. hν) for direct band gap determination.
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Figure 5. (a) Time-dependent UV-Vis absorption spectra of a DPBF solution in the presence of CZTS@GSH QDs (0.2 g/L) under 808 nm laser irradiation (0.5 W/cm2). (b) Corresponding normalized absorbance decay of DPBF at 410 nm as a function of irradiation time.
Figure 5. (a) Time-dependent UV-Vis absorption spectra of a DPBF solution in the presence of CZTS@GSH QDs (0.2 g/L) under 808 nm laser irradiation (0.5 W/cm2). (b) Corresponding normalized absorbance decay of DPBF at 410 nm as a function of irradiation time.
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Figure 6. 1O2 emission at 1200–1350 nm induced by the commercial Rose Bengal and CZTS@GSH QDs in ethanol under excitation with a 530 nm light.
Figure 6. 1O2 emission at 1200–1350 nm induced by the commercial Rose Bengal and CZTS@GSH QDs in ethanol under excitation with a 530 nm light.
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Figure 7. (a) Photothermal heating curves of aqueous dispersions of CZTS@GSH QDs at different concentrations under 808 nm laser irradiation (0.5 W/cm2). (b) The temperature change in the CZTS@GSH QDs aqueous solution upon irradiation with the 808 nm laser and then shutting down the laser power.
Figure 7. (a) Photothermal heating curves of aqueous dispersions of CZTS@GSH QDs at different concentrations under 808 nm laser irradiation (0.5 W/cm2). (b) The temperature change in the CZTS@GSH QDs aqueous solution upon irradiation with the 808 nm laser and then shutting down the laser power.
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Figure 8. Viability of 4T1 cells after incubation with various concentrations of CZTS@GSH QDs for 12, 24, and 36 h.
Figure 8. Viability of 4T1 cells after incubation with various concentrations of CZTS@GSH QDs for 12, 24, and 36 h.
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Lu, N.; Zang, Y.; Kong, L. Engineering Biocompatible Glutathione-Capped Cu2ZnSnS4 Quantum Dots Toward Integrated Photothermal and Photodynamic Effects. Materials 2026, 19, 763. https://doi.org/10.3390/ma19040763

AMA Style

Lu N, Zang Y, Kong L. Engineering Biocompatible Glutathione-Capped Cu2ZnSnS4 Quantum Dots Toward Integrated Photothermal and Photodynamic Effects. Materials. 2026; 19(4):763. https://doi.org/10.3390/ma19040763

Chicago/Turabian Style

Lu, Ning, Yufeng Zang, and Lingshuai Kong. 2026. "Engineering Biocompatible Glutathione-Capped Cu2ZnSnS4 Quantum Dots Toward Integrated Photothermal and Photodynamic Effects" Materials 19, no. 4: 763. https://doi.org/10.3390/ma19040763

APA Style

Lu, N., Zang, Y., & Kong, L. (2026). Engineering Biocompatible Glutathione-Capped Cu2ZnSnS4 Quantum Dots Toward Integrated Photothermal and Photodynamic Effects. Materials, 19(4), 763. https://doi.org/10.3390/ma19040763

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