Gold nanoparticles conjugated with epidermal growth factor and gadolinium for precision delivery of contrast agents in magnetic resonance imaging.

The utilization of contrast agents in magnetic resonance imaging (MRI) has become increasingly important in clinical diagnosis. However, the low diagnostic specificity of this technique is a limiting factor for the early detection of tumors. To develop a new contrast agent with a specific target for early stage tumors, we present the synthesis and characterization of a nanocontrast composed of gold nanoparticles (AuNPs), gadopentetic acid (Gd-DTPA), and epidermal growth factor (EGF). Carbodiimide-based chemistry was utilized to modify Gd-DTPA for functionalization with AuNPs. This resulted in the formation of the Au@Gd-EGF nanocontrast. The relaxation rate (1/T1) of the nanocontrast was analyzed using MRI, and cytotoxicity was determined based on cell viability and mitochondrial activity in a human breast adenocarcinoma cell line. Fourier-transform infrared spectroscopy analysis confirmed the effectiveness of carbodiimide in the formation of the Gd-DTPA-cysteamine complex in the presence of bands at 930, 1042, 1232, 1588, and 1716 cm-1. The complexes exhibited good interactions with the AuNPs. However, the signal intensity of the Au@Gd-EGF nanocontrast was lower than that of the commercial contrast agent because the r1/r2 relaxivities of the Gd-DTPA-based contrast agents were lower than those of the gadoversetamide-based molecules. The Au@Gd-EGF nanocontrast agent exhibited good biocompatibility, low cytotoxicity, and high signal intensity in MRI with active targeted delivery, suggesting significant potential for future applications in the early diagnosis of tumors.

Hydroxyapatite microspheres used as a drug delivery system for gliosarcoma strain 9l/Lacz treatment by photodynamic therapy protocols.

BACKGROUND: Hydroxyapatite (HAp) presents similarities with the human bone structure and presents properties such as biodegradability, biocompatibility, and osteoconductivity, which favors its use in prostheses implants and enables its use as a vehicle for the delivery of photosensitizers (PS) from systems of release (DDS) for photodynamic therapy applications Methods: In this work was to synthesized hydroxyapatite microspheres (meHAp), encapsulated with chloroaluminium phthalocyanine (ClAlPc), for DDS. meHAp was synthesized using vaterite as a template. The drug was encapsulated by mixing meHAp and a 50.0 mg.mL-1 ClAlPc solution. Photochemical, photophysical, and photobiological studies characterized the system. RESULTS: The images from the SEM analysis showed the spherical form of the particles. All spectroscopic results showed excellent photophysical parameters of the drug studied when served in the meHAp system. The incorporation efficiency was 57.8 %. The trypan blue exclusion test results showed a significant reduction (p < 0.05) in cell viability for the groups treated with PDT at all concentrations above 250 µg.mL-1. In 9 L/lacZ gliosarcoma cells, PDT mediated at concentrations from 250 to 62.5 µg.mL-1 reduced cell viability by more than 98 %. In the cell internalization study, it was possible to observe the internalization of phthalocyanines at 37 °C, with the accumulation of PS in the cytoplasm and inside the nucleus in the two tested concentrations. CONCLUSIONS: From all the results presented throughout the article, the meHAp system shows promise for use as a modified release system (DSD) in photodynamic therapy.

Nano-antibiotic based on silver nanoparticles functionalized to the vancomycin-cysteamine complex for treating Staphylococcus aureus and Enterococcus faecalis.

BACKGROUND: Bacterial resistance is defined as a microorganism's capacity to develop mechanisms for resisting a determined antimicrobial. Gram-positive bacteria, such as Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis), are internationally recognized among the isolates with this resistance profile. In this context, the demand for new medicines has risen, and silver nanoparticles (AgNPs) have been highlighted, especially for their anti-bacterial effects. To develop a nano-antibiotic for treating these Gram-positive strains, we herein report synthesizing and characterizing a nano-antibiotic based on AgNPs functionalized with the complex vancomycin-cysteamine. METHODS: AgNPs were produced using the bottom-up methodology and functionalized with vancomycin modified by the carbodiimide chemistry, forming Ag@vancomycin. Susceptibility tests were performed using S. aureus and E. faecalis strains to assess the bacteriostatic and bactericidal potential of the developed nano-antibiotic. RESULTS: Fourier transform infrared spectroscopy measurements showed the efficacy of vancomycin chemical modification, and the characteristic bands of AgNPs functionalization with the antibiotic. The increase in the nano-antibiotic average hydrodynamic diameter observed by dynamic light scattering proved the presence of vancomycin at the surface of AgNPs. The data from the minimum inhibitory concentration and minimal bactericidal concentration assays tested on standard and clinical planktonic strains of S. aureus and E. faecalis presented excellent performance. CONCLUSION: The results indicate the promising development of a new nano-antibiotic in which the functionalization potentiates the bacteriostatic action of AgNPs and vancomycin with greater efficacy against Gram-positive strains.

Vaterite microparticle-loaded methylene blue for photodynamic activity in macrophages infected with Leishmania braziliensis.

Calcium carbonate (CaCO3) exhibits a variety of crystalline phases, including the anhydrous crystalline polymorphs calcite, aragonite, and vaterite. Developing porous calcium carbonate microparticles in the vaterite phase for the encapsulation of methylene blue (MB) as a photosensitizer (PS) for use in photodynamic therapy (PDT) was the goal of this investigation. Using an adsorption approach, the PS was integrated into the CaCO3 microparticles. The vaterite microparticles were characterized by scanning electron microscopy (SEM) and steady-state techniques. The trypan blue exclusion method was used to measure the biological activity of macrophages infected with Leishmania braziliensis in vitro. The vaterite microparticles produced are highly porous, non-aggregated, and uniform in size. After encapsulation, the MB-loaded microparticles kept their photophysical characteristics. The carriers that were captured allowed for dye localization inside the cells. The results obtained in this study indicated that the MB-loaded vaterite microparticles show promising photodynamic activity in macrophages infected with Leishmania braziliensis.

Specific nanomarkers fluorescence: in vitro analysis for EGFR overexpressed cells in triple-negative breast cancer and malignant glioblastoma.

BACKGROUND: Epidermal Growth Factor Receptor (EGFR receptor) is encoded by the EGFR gene. EGFR receptor signaling pathways are activated by EGF protein, regulating cell actions. Overexpression of EGFR receptor may be linked to malignancies with a poor prognosis. As a result, EGFR receptor is being studied for a variety of tumor diagnostics, spurring the development of innovative approaches to increase quality and efficiency. Nanomaterials can recognize cancer cells by specifically targeting of molecular pathways, underscoring the importance of nanomedicine. In this study, we synthesized EGFR-specific nanomarkers by functionalizing EGF protein and Chlorin e6 in gold nanoparticles. These nanoparticles use active targeting to deliver EGF protein to EGFR receptor, and Chlorin e6 serves as a fluorescent marker molecule METHODS: Nanomarkers were examined in vitro in MDA-MB-468 and M059J cell lines. Confocal microscopy and flow cytometry were used to examine the distribution, uptake, internalization, and fluorescence intensity of nanomarkers in vitro RESULTS: The results show that both lines examined accumulate nanomarkers. However, MDA-MB-468 had the highest intensity due to its EGFR receptor overexpression properties CONCLUSION: The findings point to ideal properties for detecting EGFR receptor overexpressed cells.

Synthesis, characterization, and evaluation of chloroaluminium phthalocyanine incorporated in poly(ε-caprolactone) nanoparticles for photodynamic therapy.

BACKGROUND: The use of nanotechnology has been widely used in biomedical science, including orthopedic implants, tissue engineering, cancer therapy and drug elution from nanoparticle systems, such as poly-caprolactone (PCL) nanoparticles, which stand out mainly for their biocompatibility, being considered as effective carriers for photosensitizing drugs (PS) in photodynamic therapy (PDT) protocols. METHODS: This manuscript describes the synthesis and characterization of PCL nanoparticles for controlled release of the drug chloro-aluminum phthalocyanine (ClAlPc) as a photosensitizer for application in PDT. The PCL-ClAlPc nanoparticles were developed by the nanoprecipitation process. The structure and morphology of the nanoparticles were studied with scanning electron microscopy (SEM) and with Fourier transform infrared (FTIR). The size of nanomaterials was studied using the Dynamic Light Scattering (DLS) method. Photophysical and photochemical characterizations were performed. Subsequently, photobiological studies were also used to characterize the system. RESULTS: The nanoparticles had an average diameter of 384.7 ± 138.6 nm and a polydispersity index of 0.153. SEM analysis revealed that the system formed a spherical shape typical of these delivery systems. Charging efficiency was 82.1% ± 1.2%. The phthalocyanine-loaded PCL nanoparticles maintained their photophysical behavior after encapsulation. Cell viability was determined after the dark toxicity test, and it was possible to observe that there was no evidence of toxicity in the dark, for all concentrations tested. The assay also revealed that adenocarcinoma cells treated with free ClAlPc and in the nanoformulation showed 100% cell death when subjected to PDT protocols. The intracellular location of the photosensitizer indicated a high potential for accumulation in the cytoplasm and nucleus. CONCLUSIONS: From the photophysical, photochemical and photobiological analyzes obtained, it was possible to observe that the development of PCL nanoparticles encapsulated with ClAlPc, by the nanoprecipitation method was adequate and that the in vivo release study is efficient to reduce the release rate and attenuate the burst of PS loaded on PCL nanoparticles. The results reinforce that the use of this system as drug delivery systems is useful in PDT protocols.

Triple-negative breast cancer treatment in xenograft models by bifunctional nanoprobes combined to photodynamic therapy.

Triple-negative breast cancer (TNBC) overexpresses the Epidermal Growth Factor Receptor (EGFR), a characteristic of different types of tumors, linked to worse disease prognosis and risk of recurrence. Conventional treatments are also aggressive and can be morbid.. Therefore, t improvement and development of new methods are notorious. Photodynamic Therapy (PDT) is an effective method for treating different types of cancer by using light radiation to activate a photosensitizing agent (drug) in molecular oxygen presence, promoting cell death., Improving drug uptake in target cells could contribute to PDT efficiency. Accordingly, we developed a bifunctional nanoprobe (BN), used in PDT as a a treatment method in vivo against breast cancer. The BN uses gold nanoparticles with active targeting through the Epidermal Growth Factor (EGF) protein and Chlorine e6 (Ce6) carriers. We evaluated the therapeutic efficacy of in vivo xenograft in 4 groups: Saline, BN, Ce6+PDT, and BN+PDT. As a result, we observed that the BN+PDT group exhibited an excellent effect with greater selectivity to tumor tissue and tissue damage when compared to the Saline, BN, and Ce6+PDT groups. The results indicate a potential impact on breast cancer treatment in vivo.. In conclusion, our data propose that the BN developed heightened PDT efficacy through cellular DNA repair effects and tumor microenvironment.

Gold-Coated Superparamagnetic Iron Oxide Nanoparticles Functionalized to EGF and Ce6 Complexes for Breast Cancer Diagnoses and Therapy.

Superparamagnetic iron oxide nanoparticles (SPIONs) have some limitations in the physiological environment, however, a modification on their surface, such as a core-shell structure with gold (SPIONs@Au), can enhance their applicability. In this study, SPIONs were synthesized by the chemical coprecipitation method, stabilized by sodium citrate, and followed by the gold-coating process. SPIONs@Au were functionalized with EGF-α-lipoic acid and chlorin e6 (Ce6)-cysteamine complexes, composing a Theranostic Nanoprobe (TP). The outcomes showed that the SPIONs@Au had changed in color to red and had an absorption band centered at 530 nm. The coating was verified in the TEM micrographs in bright and dark fields by EDS mapping, which indicated the presence of Au and Fe. The Ce6-cysteamine complex had a resonant band at 670 nm that enabled the diagnosis of biological samples using fluorescence analysis. In the measure of TNBC cell uptake, the maximum value of TP fluorescence intensity was obtained within 4 h of internalization. At 2 h, the incorporation of the TP in the cytoplasm as well as in the nuclei was observed, suggesting that it could be employed as a diagnostic marker. The PTT results showed significant percentages of apoptosis in the TNBC cell line, which confirms the efficacy of the TP.

Finding reduced Raman spectroscopy fingerprint of skin samples for melanoma diagnosis through machine learning.

Early-stage detection of cutaneous melanoma can vastly increase the chances of cure. Excision biopsy followed by histological examination is considered the gold standard for diagnosing the disease, but requires long high-cost processing time, and may be biased, as it involves qualitative assessment by a professional. In this paper, we present a new machine learning approach using raw data for skin Raman spectra as input. The approach is highly efficient for classifying benign versus malignant skin lesions (AUC 0.98, 95% CI 0.97-0.99). Furthermore, we present a high-performance model (AUC 0.97, 95% CI 0.95-0.98) using a miniaturized spectral range (896-1039 cm-1), thus demonstrating that only a single fragment of the biological fingerprint Raman region is needed for producing an accurate diagnosis. These findings could favor the future development of a cheaper and dedicated Raman spectrometer for fast and accurate cancer diagnosis.

Molecular detection of HPV and FT-IR spectroscopy analysis in women with normal cervical cytology.

BACKGROUND: The increase in the incidence of Cervical Cancer in the female population worldwide has been an issue that deserves further attention from the scientific community. Several studies have already proven the relationship of its development with the molecular mechanisms that Human Papillomavirus (HPV) induces in cervical cells. The gene amplification provided by molecular biology techniques has been used as the gold standard diagnostic method of this virus because of its high specificity and sensitivity.However, the high investments associated with the acquisition of reagents, equipment and labor demonstrate the need for the development of more accessible techniques that present the same accuracy. FT-IR spectroscopy has been studied as an inexpensive and easily accessible technology that can provide the differentiation of malignant and benign cells. This study aimed to demonstrate the effectiveness and sensitivity of molecular analysis by PCR in relation to cytological analysis and to evaluate the sensitivity of FT-IR spectroscopy in the diagnosis of HPV for cervical cancer prevention. METHODS: Cervical fluid samples obtained from 50 patients with absence of cellular lesion by cytological analysis were analyzed by molecular and spectroscopic analyzes. Oncotic colpocitology analysis was performed by the Papanicolaou staining, amplification of the L1 viral gene by PCR was performed using primers MY09 and MY11 and biochemical analysis of the fluids by FT-IR was performed using the Spectrum 400 system equipped with a microscope. RESULTS: Of the 50 patients without evident morphological alteration of the cells, seven were diagnosed by molecular analysis as positive for presence of HPV. Principal component analysis of spectroscopy was not able to separate the negative samples from the HPV positive samples and, therefore, did not present as an effective diagnostic technique. CONCLUSIONS: We highlight the efficacy, sensitivity and specificity of molecular biology by PCR in the identification of the virus and we emphasize that more studies should be used for the application of FT-IR spectroscopy in the diagnosis of this infection and its application in the prevention of cervical cancer.

FTIR study of Achilles tendinopathy: protein secondary structure changes in tendon post injury

Abstract Introduction Tendinopathy, a disease involving tendon inflammation and damage, results in considerable productivity and economic losses for the patient and the society. Currently available diagnosis/ treatment monitoring modalities are less efficacious and highly subjective, underlying the need for better tools. Previously, we have shown that Fourier Transform Infrared (FTIR) spectroscopy has potential in tendinopathy diagnosis/ monitoring, when combined with multivariate statistical analysis. The current study explores the spectral range that gave the best results in statistical analysis, to discover protein secondary structures associated with tendon injury and recovery that can act as markers of disease. Methods Animals (n=60) underwent a surgery in which Achilles tendon were injured by dropping a 20g weight. Rats were divided into three groups (n=20) - control (C), Achilles tendon injury (I) and Achilles tendon injury treated with amniotic membrane fragment treated (T). FTIR spectra were obtained from each group 3, 7, 14, and 28 days post injury/ treatment. Results Triple helix, β-turn, and disordered structure levels differ between control, injured and treated tendons over the time period studied. Parallel β-sheets increase steadily over time in treated tendons compared to control and injured. Conclusion Combined analysis of Triple helix, β- sheets, β-turn, and disordered structure levels may be useful for tendinopathy diagnosis and treatment monitoring. However, further studies in this area are required to confirm the findings.

Photodithazine photodynamic effect on viability of 9L/lacZ gliosarcoma cell line.

Even with the advances of conventional treatment techniques, the nervous system cancer prognosis is still not favorable to the patient which makes alternative therapies needed to be studied. Photodynamic therapy (PDT) is presented as a promising therapy, which employs a photosensitive (PS) agent, light wavelength suitable for the PS agent, and molecular oxygen, producing reactive oxygen species in order to induce cell death. The aim of this study is to observe the PDT action in gliosarcoma cell using a chlorin (Photodithazine, PDZ). The experiments were done with 9L/lacZ lineage cells, grown in a DMEM medium supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin solution and put in a culture chamber at 37 °C with an atmosphere of 5% CO2. The PS agent used was the PDZ to an LED light source device (Biopdi/IRRAD-LED 660) in the 660-nm region. The location of the PS agent was analyzed by fluorescence microscopy, and cell viability was analyzed by MTT assay (mitochondrial activity), exclusion by trypan blue (cell viability), and morphological examination through an optical microscope (Leica MD 2500). In the analysis of the experiments with PDZ, there was 100% cell death at different concentrations and clear morphological differences in groups with and without treatment. Furthermore, it was observed that the photodithazine has been focused on all nuclear and cytoplasmic extension; however, it cannot be said for sure whether the location is in the inside core region or on the plasma membrane. In general, the PDZ showed a promising photosensitive agent in PDT for the use of gliosarcoma.

Evaluation of methylene blue as photosensitizer in promastigotes of Leishmania major and Leishmania braziliensis.

The cutaneous leishmaniasis is caused by the protozoan of the genus Leishmania. It is considered by WHO as a public health issue and a neglected disease, which affects rural workers and it is also a risk to travelers in endemic areas. The conventional treatment is toxic and leads to severe side effects. The photodynamic therapy has been studied as an alternative treatment to cutaneous leishmaniasis. This study aimed to evaluate the methylene blue internalization and the impact of the PDT in the viability and morphology of Leishmania major and Leishmania braziliensis promastigote in culture medium. The fluorescence microscopy was used to determine the MB localization. To evaluate the mitochondrial activity (MTT), viability (Trypan blue test) and the morphological alterations both species were incubated with the MB in concentrations starting in 500µg/ml, in serial dilution, until 7,8µg/ml. The fluorescence microscopy demonstrated that the MB is internalized by both species after one hour of incubation. The MB presented low toxicity at the dark and the PDT was capable of decreasing the viability in more than 70% in the higher concentrations tested. The PDT also triggered significant morphological alterations in the Leishmania promastigotes. The results presented in this study are an indicative that the MB is a photosensitizer with promising potential to clinical application, besides its low cost.

Amniotic membrane as an option for treatment of acute Achilles tendon injury in rats

Abstract Purpose: To evaluate the effect of human amniotic membrane (hAM) fragment on inflammatory response, proliferation of fibroblast and organization of collagen fibers in injured tendon. Methods: Sixty rats were divided into 3 groups: C - surgical procedures without tendon lesion and with simulation of hAM application; I - surgical procedures, tendon injury and simulation of hAM application; T - surgical procedures, tendon injury and hAM application. These groups were subdivided into four experimental times (3, 7, 14 and 28 days). The samples underwent histological analysis and ATR-FTIR spectroscopy. Results: Histological analysis at 14 days, the T group showed collagen fibers with better alignment. At 28 days, the I group presented the characteristics described for the T group at 14 days, while this group presented aspects of a mature connective tissue. FT-IR analysis showed a clear distinction among the three groups at all experimental times and groups T and I presented more similarities to each other than to group C. Conclusion: Acute injury of tendon treated with human amniotic membrane fragment showed a faster healing process, reduction in inflammatory response, intense proliferation of fibroblasts and organization of collagen fibers.

FTIR and SEM analysis applied in tissue engineering for root recovering surgery.

Gingival recession is defined by the displacement of the gingival margin in the apical direction, which overcomes the cementum enamel junction. The etiology of gingival retraction is related to tissue inflammation caused by the accumulation of biofilm, by trauma from brushing action. Aesthetic periodontal surgery aims to return the root coverage to aesthetic harmony, and reduce the risk of periodontal disease and caries. To assist in the root coverage process, the porcine collagen matrix (PCM) has been widely studied. The objectives of this study are to identify the types of collagen that make up the PCM and analyze their morphology. For this, five PCM fragments, 2 mm (thickness) × 2.6 mm (width), were analyzed with the aid of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The analysis by SEM showed that the PCM consists of two layers; the surface layer is compact, low porosity, and smooth surface, and a foamed underlying layer has high porosity. Through FTIR we identified that the surface and underlying layers are composed of collagen types I and III, respectively. This biomaterial is conducive to root coverage; it allows adsorption and cell proliferation following the matrix resorption and periodontal tissue neoformation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1326-1329, 2017.

Analysis of serum cortisol levels by Fourier Transform Infrared Spectroscopy for diagnosis of stress in athletes

Abstract Introduction Fourier-transform infrared (FT-IR) spectroscopy is a technique with great potential for body fluids analyses. The aim of this study was to examine the impact of session training on cortisol concentrations in rugby players by means of infrared analysis of serum. Methods Blood collections were performed pre, post and 24 hours after of rugby training sessions. Serum cortisol was analyzed by FT-IR spectroscopy and chemiluminescent immunoassay. Results There was a significant difference between the integrated area, in the region of 1180-1102 cm-1, of the spectra for pre, post and post 24 h serums. The cortisol concentration obtained by chemiluminescent immunoassay showed no significant difference between pre, post and post 24 h. Positive correlations were obtained between the techniques (r = 0.75), post (r = 0.83) and post 24 h (r = 0.73). Conclusion The results showed no increase in cortisol levels of the players after the training sessions, as well as positive correlations indicating that FT-IR spectroscopy have produced promising results for the analysis of serum for diagnosis of stress.

Application of FT-IR spectroscopy to assess physiological stress in rugby players during fatigue test

AbstractIntroduction: The diagnosis based on salivary biomarkers provides information about the physiological condition. However, the clinical trials used to analyze these biomarkers are relatively expensive and laborious. Thus, the purpose of this study was to identify the physiological stress in players using Fourier transform infrared spectroscopy (FT-IR). Methods Thirteen male rugby players were submitted to the treadmill fatigue test and saliva collections were performed before and immediately after test. The FT-IR spectra of saliva samples were analyzed by the second derivative and cluster analysis. Results From the results of cluster analysis were possible to discriminate the spectra of saliva before and after physical effort using the spectral region between 1490 to 1420 cm–1. Only the saliva spectra from two players were not discriminated in pre-exercise group and post-exercise group, which are in agreement with lowest value of heart rates. Conclusion The second derivative showed differences between the average spectra of saliva samples collected pre and post-test, which explain the spectra discrimination by the cluster analysis using a specific infrared region for the identification of physiological stress.

Chlorin E6 phototoxicity in L. major and L. braziliensis promastigotes-In vitro study.

BACKGROUND: Cutaneous leishmaniasis is a zoonosis caused by protozoa of the genus Leishmania. Conventional treatments are long and aggressive, and they trigger a diversity of side effects. Photodynamic Therapy was originally proposed as a treatment for cancer, and it now appears to be a promising therapy for local treatment with fewer side effects of infectious diseases. METHODS: This study aimed to evaluate Chlorin e6 internalization by Leishmania major and Leishmania braziliensis promastigotes and its viability and effects on mitochondrial activity. Control groups were kept in the dark, while PDT groups received fluence of 10J/cm(2) (660nm). Chlorin internalization was evaluated using confocal microscopy after one hour of incubation for both species. RESULTS: The mitochondrial activity was evaluated by MTT assay, and viability was measured by the Trypan blue exclusion test. Giemsa staining was used to observe morphological changes. PS was internalized in both species and mitochondrial activity changed in all groups. However, the obtained MTT and Trypan results indicated that despite the change in mitochondrial activity in the dark groups, their viability was not affected, whereas the PDT treated groups had significantly reduced viability. Morphology was drastically altered in PDT treated groups, while groups kept in the dark exhibited the standard morphology. CONCLUSIONS: This study demonstrates that Chlorin has great potential for being used in PDT as a treatment for cutaneous leishmaniasis, although more studies are needed to determine in vivo application protocols.

In vitro evaluation of photodynamic therapy using curcumin on Leishmania major and Leishmania braziliensis.

Cutaneous leishmaniasis is an infectious disease caused by the Leishmania protozoan. The conventional treatment is long-lasting and aggressive, in addition to causing harmful effect. Photodynamic therapy has emerged as a promising alternative treatment, which allows local administration with fewer side effects. This study investigated the photodynamic activity of curcumin on Leishmania major and Leishmania braziliensis promastigote. Both species were submitted to incubation with curcumin in serial dilutions from 500 µg/ml up to 7.8 µg/ml. Control groups were kept in the dark while PDT groups received a fluency of 10 J/cm(2) at 450 nm. Mitochondrial activity was assessed by MTT assay 18 h after light treatment, and viability was measured by Trypan blue dye exclusion test. Morphological alterations were observed by Giemsa staining. Confocal microscopy showed the uptake of curcumin by both tested Leishmania species. Mitochondrial activity was inconclusive to determine viability; however, Trypan blue test was able to show that curcumin photodynamic treatment had a significant effect on viability of parasites. The morphology of promastigotes was highly affected by the photodynamic therapy. These results indicated that curcumin may be a promising alternative photosensitizer, because it presents no toxicity in the dark; however, further tests in co-culture with macrophages and other species of Leishmania should be conducted to determine better conditions before in vivo tests are performed.