Sandra  Pérez-Buitrago

Sandra Pérez-Buitrago

orcid

Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 February 2020 in Scientific Reports
Verified
Journal Article
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PMPedro Mena-Giraldo
Pedro Mena-Giraldo
SPSandra Pérez-Buitrago
Sandra Pérez-Buitrago
MLMaritza Londoño-Berrío
Maritza Londoño-Berrío
IOIsabel C. Ortiz-Trujillo
Isabel C. Ortiz-Trujillo
LHLina M. Hoyos-Palacio
Lina M. Hoyos-Palacio
Jahir OrozcoJahir Orozco
Jahir Orozco
Nanoencapsulation is a rapidly expanding technology to enclose cargo into inert material at the nanoscale size, which protects cargo from degradation, improves bioavailability and allows for controlled release. Encapsulation of drugs into functional nanocarriers enhances their specificity, targeting ability, efficiency, and effectiveness. Functionality may come from cell targeting biomolecules that direct nanocarriers to a specific cell or tissue. Delivery is usually mediated by diffusion and erosion mechanisms, but in some cases, this is not sufficient to reach the expected therapeutic effects. This work reports on the development of a new photoresponsive polymeric nanocarrier (PNc)-based nanobioconjugate (NBc) for specific photo-delivery of cargo into target cells. We readily synthesized the PNcs by modification of chitosan with ultraviolet (UV)-photosensitive azobenzene molecules, with Nile red and dofetilide as cargo models to prove the encapsulation/release concept. The PNcs were further functionalized with the cardiac targeting transmembrane peptide and efficiently internalized into cardiomyocytes, as a cell line model. Intracellular cargo-release was dramatically accelerated upon a very short UV-light irradiation time. Delivering cargo in a time-space controlled fashion by means of NBcs is a promising strategy to increase the intracellular cargo concentration, to decrease dose and cargo side effects, thereby improving the effectiveness of a therapeutic regime.

31 July 2022 in Polymers
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Journal Article
Open access
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MLMaritza Londoño-Berrío
Maritza Londoño-Berrío
SPSandra Pérez-Buitrago
Sandra Pérez-Buitrago
IOIsabel Cristina Ortiz-Trujillo
Isabel Cristina Ortiz-Trujillo
LPLina Marcela Hoyos Palacio
Lina Marcela Hoyos Palacio
LOLuz Yaneth Orozco
Luz Yaneth Orozco
PMPedro Mena-Giraldo
Pedro Mena-Giraldo
Drug nanoencapsulation increases the availability, pharmacokinetics, and concentration efficiency for therapeutic regimes. Azobenzene light-responsive molecules experience a hydrophobicity change from a polar to an apolar tendency by trans–cis photoisomerization upon UV irradiation. Polymeric photoresponse nanoparticles (PPNPs) based on azobenzene compounds and biopolymers such as chitosan derivatives show prospects of photodelivering drugs into cells with accelerated kinetics, enhancing their therapeutic effect. PPNP biocompatibility studies detect the safe concentrations for their administration and reduce the chance of side effects, improving the effectiveness of a potential treatment. Here, we report on a PPNP biocompatibility evaluation of viability and the first genotoxicity study of azobenzene-based PPNPs. Cell line models from human ventricular cardiomyocytes (RL14), as well as mouse fibroblasts (NIH3T3) as proof of concept, were exposed to different concentrations of azobenzene-based PPNPs and their precursors to evaluate the consequences on mitochondrial metabolism (MTT assay), the number of viable cells (trypan blue exclusion test), and deoxyribonucleic acid (DNA) damage (comet assay). Lethal concentrations of 50 (LC50) of the PPNPs and their precursors were higher than the required drug release and synthesis concentrations. The PPNPs affected the cell membrane at concentrations higher than 2 mg/mL, and lower concentrations exhibited lesser damage to cellular genetic material. An azobenzene derivative functionalized with a biopolymer to assemble PPNPs demonstrated biocompatibility with the evaluated cell lines. The PPNPs encapsulated Nile red and dofetilide separately as model and antiarrhythmic drugs, respectively, and delivered upon UV irradiation, proving the phototriggered drug release concept. Biocompatible PPNPs are a promising technology for fast drug release with high cell interaction opening new opportunities for azobenzene biomedical applications.

13 July 2020 in Quantitative InfraRed Thermography Journal
Verified
Journal Article
Closed access
SPSandra Pérez-Buitrago
Sandra Pérez-Buitrago
STSara Tobón-Pareja
Sara Tobón-Pareja
YGYeraldín Gómez-Gaviria
Yeraldín Gómez-Gaviria
AGAdriana Guerrero-Peña
Adriana Guerrero-Peña
GDGloria Díaz-Londoño
Gloria Díaz-Londoño
Multiple sclerosis (MS) is a progressive and degenerative disease that causes nerve conduction blocks due to demyelination in the central nervous system. Most MS patients experience a worsening of clinical signs and neurological symptoms when they are exposed to heat due to a thermoregulatory dysfunction. This paper proposes a novel methodology to understand temperature changes in MS patients by obtaining and evaluating texture features from infrared thermography (IRT) images. For that purpose, images of the legs of a MS patient and a healthy control subject with similar physical characteristics (while at rest and in a standing position) were recorded using a FLIR A655SC infrared camera. In the quantitative analysis of the resulting IRT images, three texture features (average, entropy, and uniformity) were computed, and the results were compared using statistical techniques. The statistical analysis showed that temperatures in the MS patient were not normally distributed, while those in the healthy control subject were normally distributed. In addition, significant differences in average, entropy, and uniformity were found between subjects. This methodology enables a quantitative evaluation of thermal distributions over different regions of the body and can be used in further studies into temperature changes in MS patients.

1 July 2019
Verified
Conference Paper
Closed access
SPSandra Pérez-Buitrago
Sandra Pérez-Buitrago
PMPedro Mena-Giraldo
Pedro Mena-Giraldo
RPRodolfo Pinal
Rodolfo Pinal
LHLina Hoyos-Palacio
Lina Hoyos-Palacio
Controlled release by stimulus-responsive nanoparticles is oriented to increase the specificity of drug delivery, to improve the therapy effectiveness and minimizing side effects. This work presents the synthesis of photosensitive-polymeric nanoparticles as a potential system for localized drug delivery. First, the photoisomerizable amphiphilic-copolymer poly2-[4-phenylazophenoxy]ethyl acrylate-co-acrylic acid (PPAPE), was synthesized. Then, PPAPE was employed to prepare micellar nanoparticles by the nanoprecipitation method. Characterizations of the polymer were performed by proton nuclear magnetic resonance, X-ray photoelectron spectroscopy and FTIR spectroscopy. The morphology of the nanoparticles was analyzed by dynamic light scattering and transmission electron microscopy. Also, photostimulation response was confirmed by UV-VIS spectroscopy. Results indicate that the obtained photoresponsive nanoparticles have the size and photoisomerization necessary to perform the specific release of drugs.

6 April 2015 in Biomedical Optics Express
Verified
Journal Article
Closed access
JGJuly Galeano
July Galeano
SPSandra Pérez-Buitrago
Sandra Pérez-Buitrago
YMYonatan Montoya
Yonatan Montoya
DBDeivid Botina
Deivid Botina
JGJohnson Garzón
Johnson Garzón
Blind Source Separation methods (BSS) aim for the decomposition of a given signal in its main components or source signals. Those techniques have been widely used in the literature for the analysis of biomedical images, in order to extract the main components of an organ or tissue under study. The analysis of skin images for the extraction of melanin and hemoglobin is an example of the use of BSS. This paper presents a proof of concept of the use of source separation of ex-vivo aorta tissue multispectral Images. The images are acquired with an interference filter-based imaging system. The images are processed by means of two algorithms: Independent Components analysis and Non-negative Matrix Factorization. In both cases, it is possible to obtain maps that quantify the concentration of the main chromophores present in aortic tissue. Also, the algorithms allow for spectral absorbance of the main tissue components. Those spectral signatures were compared against the theoretical ones by using correlation coefficients. Those coefficients report values close to 0.9, which is a good estimator of the method's performance. Also, correlation coefficients lead to the identification of the concentration maps according to the evaluated chromophore. The results suggest that Multi/hyper-spectral systems together with image processing techniques is a potential tool for the analysis of cardiovascular tissue.

18 December 2025 in BMC Health Services Research
Verified
Journal Article
Open access
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CGCamila Gianella
Camila Gianella
GSGabriela Salmon-Mulanovich
Gabriela Salmon-Mulanovich
JBJohanni Bohorquez-Gutierrez
Johanni Bohorquez-Gutierrez
PTPedro Tapia
Pedro Tapia
SPSandra Pérez-Buitrago
Sandra Pérez-Buitrago
Cervical cancer (CC) is the most common and second-most deadly cancer among Peruvian women, despite national authorities’ sustained political and bud