Publications by authors named "Sila Appak-Baskoy"

9 Publications

  • Page 1 of 1

Multifunctional nanoparticles as theranostic agents for therapy and imaging of breast cancer.

J Photochem Photobiol B 2021 May 29;218:112110. Epub 2020 Dec 29.

Institute for Biomedical Engineering, Science and Technology (iBEST), a partnership between Ryerson University and St. Michael's Hospital, Toronto, ON M5B 1T8, Canada; Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, ON, M5B 1T8, Canada; Department of Physics, Ryerson University, Toronto, ON M5B 2K3, Canada. Electronic address:

Over the last decade, there has been significant developments in nanotechnology, in particular for combined imaging and therapeutic applications (theranostics). The core or shell of nanoemulsions (NEs) can be loaded with various therapeutic agents, including drugs with low solubility for effective treatment, or various imaging agents for specific imaging modalities (e.g., MRI, fluorescence). In this work, perfluorohexane (PFH) NEs were synthesized for theranostic applications and were coupled to silica coated gold nanoparticles (scAuNPs) to increase the generation of PFH bubbles upon laser induced vaporization (i.e., optical droplet vaporization). The localized heat generated from the absorption properties of these nanoparticles (used to provide photoacoustic signals) can also be used to treat cancer without significantly damaging nearby healthy tissues. The theranostic potential of these PFH-NEs for contrast imaging of tumors and as a drug-delivery vehicle for therapeutic purposes were demonstrated for both in vitro and in vivo systems using a combination of photoacoustic, ultrasound and fluorescence imaging modalities. The ability of PFH-NEs to couple with scAuNPs, attach to the membranes of cancer cells and internalize within cancer cells, are encouraging for targeted chemotherapeutic applications for directly inducing cancer cell death via vaporization in clinical settings.
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http://dx.doi.org/10.1016/j.jphotobiol.2020.112110DOI Listing
May 2021

Dosage-controlled intracellular delivery mediated by acoustofluidics for lab on a chip applications.

Lab Chip 2021 May;21(9):1788-1797

Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, ON M5B 1T8, Canada and Department of Physics, Ryerson University, Toronto, ON M5B 2K3, Canada.

Biological research and many cell-based therapies rely on the successful delivery of cargo materials into cells. Intracellular delivery in an in vitro setting refers to a variety of physical and biochemical techniques developed for conducting rapid and efficient transport of materials across the plasma membrane. Generally, the techniques that are time-efficient (e.g., electroporation) suffer from heterogeneity and low cellular viability, and those that are precise (e.g., microinjection) suffer from low-throughput and are labor-intensive. Here, we present a novel in vitro microfluidic strategy for intracellular delivery, which is based on the acoustic excitation of adherent cells. Strong mechanical oscillations, mediated by Lamb waves, inside a microfluidic channel facilitate the cellular uptake of different size (e.g., 3-500 kDa, plasmid encoding EGFP) cargo materials through endocytic pathways. We demonstrate successful delivery of 500 kDa dextran to various adherent cell lines with unprecedented efficiency in the range of 65-85% above control. We also show that actuation voltage and treatment duration can be tuned to control the dosage of delivered substances. High viability (≥91%), versatility across different cargo materials and various adherent cell lines, scalability to hundreds of thousands of cells per treatment, portability, and ease-of-operation are among the unique features of this acoustofluidic strategy. Potential applications include targeting through endocytosis-dependant pathways in cellular disorders, such as lysosomal storage diseases, which other physical methods are unable to address. This novel acoustofluidic method achieves rapid, uniform, and scalable delivery of material into cells, and may find utility in lab-on-a-chip applications.
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http://dx.doi.org/10.1039/d0lc01303jDOI Listing
May 2021

Investigation into the protective effects of seed against cyclophosphamide-induced testicular injury in Sprague Dawley rats.

Drug Chem Toxicol 2020 Dec 6:1-8. Epub 2020 Dec 6.

Havran State Hospital, Balıkesir, Turkey.

For centuries, Turkey has been a significant location here around 80 species of with differing names widely occur, which is also known as in treating some bacterial diseases as well as stomach and intestine inflammation. Recent studies have reported this herb family to contain numbers of bioactive compound contents. The study aims to investigate the protective effects of (HT) upon oxidative stress and apoptosis in a rat model in which testes injury was induced by CP. The testicular injury was caused using CP (150 mg/kg). The rats were treated with a single dose (100 mg/kg) of methanol extract of HT to investigate various biochemical markers in the serum and plasma of blood samples apart from assessing the prognosis of CP-induced testicular damage. Added to that, histological analyses were performed to identify possible structural changes and apoptotic indicators, like Bax, Caspase-3, and Bcl-2. In CP Group, there was a rise in the levels of total oxidant status (TOS), malondialdehyde (MDA), oxidative stress index (OSI), Caspase-3, and Bax while superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), Bcl-2, and total antioxidant capacity (TAC) all decreased. Also, our histological analysis showed damaged testes. On the other hand, neither biochemical nor histological analysis showed testicular damage in HT Alone Group. In CP + HT Group, a significant number of the negatives changes due to CP were observed to have improved remarkably following an HT treatment. This study results suggest that HT could help improve CP-induced testicular injury thanks to its anti-oxidative and anti-apoptotic properties.
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http://dx.doi.org/10.1080/01480545.2020.1856130DOI Listing
December 2020

Use of photoacoustic imaging for monitoring vascular disrupting cancer treatments.

J Biophotonics 2020 Sep 5:e202000209. Epub 2020 Sep 5.

Department of Physics, Ryerson University, Toronto, Ontario, Canada.

Vascular disrupting agents disrupt tumor vessels, blocking the nutritional and oxygen supply tumors need to thrive. This is achieved by damaging the endothelium lining of blood vessels, resulting in red blood cells (RBCs) entering the tumor parenchyma. RBCs present in the extracellular matrix are exposed to external stressors resulting in biochemical and physiological changes. The detection of these changes can be used to monitor the efficacy of cancer treatments. Spectroscopic photoacoustic (PA) imaging is an ideal candidate for probing RBCs due to their high optical absorption relative to surrounding tissue. The goal of this work is to use PA imaging to monitor the efficacy of the vascular disrupting agent 5,6-Dimethylxanthenone-4-acetic acid (DMXAA) through quantitative analysis. Then, 4T1 breast cancer cells were injected subcutaneously into the left hind leg of eight BALB/c mice. After 10 days, half of the mice were treated with 15 mg/kg of DMXAA and the other half were injected with saline. All mice were imaged using the VevoLAZR X PA system before treatment, 24 and 72 hours after treatment. The imaging was done at six wavelengths and linear spectral unmixing was applied to the PA images to quantify three forms of hemoglobin (oxy, deoxy and met-hemoglobin). After imaging, tumors were histologically processed and H&E and TUNEL staining were used to detect the tissue damage induced by the DMXAA treatment. The total hemoglobin concentration remained unchanged after treatment for the saline treated mice. For DMXAA treated mice, a 10% increase of deoxyhemoglobin concentration was detected 24 hours after treatment and a 22.6% decrease in total hemoglobin concentration was observed by 72 hours. A decrease in the PA spectral slope parameters was measured 24 hours after treatment. This suggests that DMXAA induces vascular damage, causing red blood cells to extravasate. Furthermore, H&E staining of the tumor showed areas of bleeding with erythrocyte deposition. These observations are further supported by the increase in TUNEL staining in DMXAA treated tumors, revealing increased cell death due to vascular disruption. This study demonstrates the capability of PA imaging to monitor tumor vessel disruption by the vascular disrupting agent DMXAA.
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http://dx.doi.org/10.1002/jbio.202000209DOI Listing
September 2020

Cyclophosphamide induced oxidative stress, lipid per oxidation, apoptosis and histopathological changes in rats: Protective role of boron.

J Trace Elem Med Biol 2020 Dec 30;62:126574. Epub 2020 May 30.

Eskisehir Osmangazi University, Faculty of Science and Letters, Department of Biology, TR-26480 Eskisehir, Turkey.

Background: Cyclophosphamide (CP) is an alkylating chemotherapeutic drug used in the treatment of many types of cancer. However, as with other chemotherapeutic drugs, the use of CP is limited by the damage to healthy tissues such as testes, bladder and liver as well as cancerous tissue. Boron (B) is a trace element with many biological properties such as antioxidant, anti-apoptotic and anti-lipid per oxidation.

Methods: This current study aims to determine protective effects of B on CP induced testicular toxicity. The rats were divided into 4 groups (control, CP, B and B plus CP groups). The testes of experimental animals were taken for histological, apoptotic markers and biochemical analysis.

Results: The damage to some seminifer tubules, loss of typical appearance, thinning of seminifer epithelium and relative enlargement of the tubule lumen were watched in testis of the group that administrated CP. Moreover, Bcl-2, TAC and GSH levels decreased while TOC, OSI, MDA, Bax and Caspase-3 levels increased. On the other hand, pretreatment limited to B in the B plus CP group, testicular tissue improved. In addition, Bcl-2, GSH, TAC levels increased, Bax, MDA, TOC, OSI and caspase-3 levels decreased.

Conclusion: B significantly reduced testicular lipid per-oxidation and strengthened antioxidant defenses. Our results showed that pre-treatment B can protect rat testis against CP-induced testicular damage owing to its anti-lipid per oxidation, anti-oxidant and anti-apoptotic properties.
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http://dx.doi.org/10.1016/j.jtemb.2020.126574DOI Listing
December 2020

Dancing with the Cells: Acoustic Microflows Generated by Oscillating Cells.

Small 2020 03 12;16(9):e1903788. Epub 2019 Dec 12.

Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, ON, M5B 1T8, Canada.

The interaction of a sound or ultrasound wave with an elastic object, such as a microbubble, can give rise to a steady-state microstreaming flow in its surrounding liquid. Many microfluidic strategies for cell and particle manipulation, and analyte mixing, are based on this type of flow. In addition, there are reports that acoustic streaming can be generated in biological systems, for instance, in a mammalian inner ear. Here, new observations are reported that individual cells are able to induce microstreaming flow, when they are excited by controlled acoustic waves in vitro. Single adherent cells are exposed to an acoustic field inside a microfluidic device. The cell-induced microstreaming is then investigated by monitoring flow tracers around the cell, while the structure and extracellular environment of the cell are altered using different chemicals. The observations suggest that the maximum streaming flow induced by an MDA-MB-231 breast cancer cell can reach velocities on the order of mm s , and this maximum velocity is primarily governed by the overall cell stiffness. Therefore, such cell-induced microstreaming measurements, including flow pattern and velocity magnitude, may be used as label-free proxies of cellular mechanical properties, such as stiffness.
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http://dx.doi.org/10.1002/smll.201903788DOI Listing
March 2020

Protective Effects of Boron on Cyclophosphamide-Induced Bladder Damage and Oxidative Stress in Rats.

Biol Trace Elem Res 2020 Sep 16;197(1):184-191. Epub 2019 Nov 16.

Vocational School of Health Services, Kırıkkale University, Kırıkkale, Turkey.

This study aims to investigate protective effects of boron against cyclophosphamide-induced bladder toxicity that produces oxidative stress and leads to apoptosis of the cells. In total, 24 rats were divided into 4 equal groups. The control group received saline. The 2nd experimental group received 200 mg kg of cyclophosphamide i.p. on the 4th day while the 3rd group was given only boron (200 mg kg, i.p.) for 6 days. In the 4th group, boron was given for 6 days and cyclophosphamide (200 mg kg, i.p.) was administrated on the 4th day. Twenty-four hours after the last boron or cyclophosphamide administration, rats were sacrificed under anesthesia. Bladder tissues of rats were taken for histological and immunohistochemical (apoptotic markers such as caspase-3, bcl-2, and bax) and blood was taken for the biochemical (serum total thiol, serum natural thiol, serum thiol-disulfide) analysis. Transient epithelial thinning, edema, marked inflammatory reaction, and bleeding were observed in bladders of the group that received cyclophosphamide. Also, the activity of bax and caspase-3-positive cells increased while the number of bcl-2-positive cells decreased. In the same group, serum natural thiol and total thiol levels decreased while serum disulfide levels increased, which indicates oxidative stress. On the other hand, in the boron+cyclophosphamide group pretreatment with boron protected, the bladder tissue and the number of bcl-2-positive cells increased, and bax and caspase-3-positive cells decreased, showing antiapoptotic effects of boron against cyclophosphamide-induced toxicity. In parallel with the findings of this group, native thiol and total thiol levels increased and serum disulfide levels decreased pointing out to a decreased oxidative stress. Our results indicate that boron pretreatment significantly protects rat bladder against cyclophosphamide-induced bladder damage due to its antiapoptotic and antioxidant properties.
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http://dx.doi.org/10.1007/s12011-019-01969-zDOI Listing
September 2020

Dietary protein dilution limits dyslipidemia in obesity through FGF21-driven fatty acid clearance.

J Nutr Biochem 2018 07 7;57:189-196. Epub 2018 Apr 7.

Joint Research Division Molecular Metabolic Control, German Cancer Research Center, Center for Molecular Biology, Heidelberg University and Heidelberg University Hospital, 69120 Heidelberg, Germany; Nutrient Metabolism and Signalling Lab, Dept. of Biochemistry and Molecular Biology, School of Biomedical Sciences, and Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia. Electronic address:

Recent studies have demonstrated that dietary protein dilution (PD) can promote metabolic inefficiency and improve glucose metabolism. However, whether PD can promote other aspects of metabolic health, such as improve systemic lipid metabolism, and mechanisms therein remains unknown. Mouse models of obesity, such as high-fat-diet-fed C57Bl/6 N mice, and New Zealand Obese mice were fed normal (i.e., 20%P) and protein-dilute (i.e., 5%EP) diets. FGF21-/- and Cd36-/- and corresponding littermate +/+ controls were also studied to examine gene-diet interactions. Here, we show that chronic PD retards the development of hypertrigylceridemia and fatty liver in obesity and that this relies on the induction of the hepatokine fibroblast growth factor 21 (FGF21). Furthermore, PD greatly enhances systemic lipid homeostasis, the mechanisms by which include FGF21-stimulated, and cluster of differentiation 36 (CD36) mediated, fatty acid clearance by oxidative tissues, such as heart and brown adipose tissue. Taken together, our preclinical studies demonstrate a novel nutritional strategy, as well as highlight a role for FGF21-stimulated systemic lipid metabolism, in combating obesity-related dyslipidemia.
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http://dx.doi.org/10.1016/j.jnutbio.2018.03.027DOI Listing
July 2018