Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Gül Kozalak has a total of 42 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • From nanoengineering to microphysiology: Organ-on-chip platforms for next-generation drug delivery

    by Ünal Akar, Ezgi Kestek, İlAyda Çelik, Gül Kozalak, Ali Koşar

    Nanoparticle-based drug delivery has a transformative role in therapeutic design by enabling targeted transport, controlled release, and enhanced pharmacokinetics. Traditional in vitro and animal models often fail to capture the dynamic, multicellular, and biomechanical complexity of human tissues, limiting their predictive value for translational nanomedicine. Organ-on-chip (OoC) technologies bridge this gap by recreating physiologically relevant microenvironments that integrate fluid flow, mechanical stimulation, and tissue-specific architecture, allowing nanoparticle behavior to be studied under human-relevant conditions. In this review, we provide a mechanistic framework for understanding of the interaction of nanoparticle therapeutics with microphysiological systems. We first discuss design principles of major nanoparticle platforms and highlight the effects of nano–biointerface dynamics, including protein corona formation and immune interactions, on transport and efficacy in drug delivery. A major focus of the review is on stimuli-responsive and adaptive delivery strategies, including pH-, thermal-, electrical-, magnetic-, optical-, and sensor-integrated systems and on the role of OoC platforms in quantitative evaluation of triggered release and therapeutic response in real time. We then examine organ-specific OoC models, including spanning lung, liver, heart, gut, and blood–brain barrier systems, which are helpful in explaining the regulation of nanoparticle biodistribution and therapeutic performance by tissue mechanics and physiological gradients. We further discuss emerging directions such as computational integration, digital biomarkers, and regulatory translation and the transformation of drug delivery research thanks to the synergy of nanotechnology, microphysiological engineering, and data-driven modeling. In contrast to previous reviews, this work integrates nanoparticle design, nano–biointerface dynamics, and organ-specific OoC systems to provide a mechanistic framework for evaluating and optimizing next-generation nanomedicine delivery. This review positions organ-on-chip systems as predictive design environments that not only model human physiology but also enable rational optimization of next-generation nanomedicines, accelerating the development of safer, more effective, and personalized therapeutic strategies.

  • Open Access

    Optimization of PLGA Nanoparticle Formulation via Microfluidic and Batch Nanoprecipitation Techniques

    by Gül Kozalak, Salar Heyat Davoudian, Evangelos Natsaridis, Nubia Gogniat, Ali Koşar, Oya Tagit

    Polymeric nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) are widely used in drug delivery, yet scalable and reproducible production methods remain a major challenge. In this study, we combine experimental nanoprecipitation and computational fluid dynamics (CFD) modeling to optimize PLGA nanoparticle formulation using both traditional batch and microfluidic methods. While Design of Experiments (DoE) was used to optimize the batch process, microfluidic mixing was systematically explored by varying flow parameters such as the flow rate ratio (FRR) and total flow rate (TFR). We compared two microfluidic mixer designs with Y-junction and three-inlet junction geometries to evaluate their impact on the mixing efficiency and nanoparticle formation. Experimental results revealed that the three-inlet design produced smaller, more uniform nanoparticles with superior post-lyophilization stability. CFD simulations confirmed these findings by displaying velocity fields and PLGA concentration gradients, demonstrating significantly more homogeneous mixing and efficient interfacial contact in the three-inlet configuration. Furthermore, simulated outlet concentrations were used to predict the nanoparticle size via theoretical modeling, which closely agreed with the experimental data. This integrated approach highlights the importance of microfluidic geometry in controlling nanoparticle nucleation dynamics and provides a framework for rational design of scalable nanomedicine production systems.


  • Open Access

    Bone-on-a-Chip Systems for Hematological Cancers

    by Gül Kozalak, Ali Koşar

    Hematological malignancies originating from blood, bone marrow, and lymph nodes include leukemia, lymphoma, and myeloma, which necessitate the use of a distinct chemotherapeutic approach. Drug resistance frequently complicates their treatment, highlighting the need for predictive tools to guide therapeutic decisions. Conventional 2D/3D cell cultures do not fully encompass in vivo criteria, and translating disease models from mice to humans proves challenging. Organ-on-a-chip technology presents an avenue to surmount genetic disparities between species, offering precise design, concurrent manipulation of various cell types, and extrapolation of data to human physiology. The development of bone-on-a-chip (BoC) systems is crucial for accurately representing the in vivo bone microenvironment, predicting drug responses for hematological cancers, mitigating drug resistance, and facilitating personalized therapeutic interventions. BoC systems for modeling hematological cancers and drug research can encompass intricate designs and integrated platforms for analyzing drug response data to simulate disease scenarios. This review provides a comprehensive examination of BoC systems applicable to modeling hematological cancers and visualizing drug responses within the intricate context of bone. It thoroughly discusses the materials pertinent to BoC systems, suitable in vitro techniques, the predictive capabilities of BoC systems in clinical settings, and their potential for commercialization.


  • Open Access

    Thermoresponsive Nanocarriers Transduced by Inorganic Nanoparticles: Design Considerations and Applications in Drug Delivery

    by Anamarija Nikoletić, Mirela Maleković, Gül Kozalak, Cornelia G. Palivan, Oya Tagit

    Thermoresponsive polymers, which undergo phase transitions within physiologically tolerated temperatures, are key to developing drug delivery systems (DDS) with precise spatial and temporal control, potentially addressing challenges associated with the treatment of complex diseases. Inorganic nanoparticles with unique optical, electronic, and magnetic properties serve as efficient transducers, converting external stimuli into localized heat to trigger thermoresponsive nanocarriers. This review explores the design and application of thermoresponsive nanocarriers transduced by inorganic nanoparticles as DDS. Following a brief description of temperature‐triggered phase transition of polymers and heat generation mechanisms by inorganic nanoparticles, strategies to integrate these components into hybrid systems are described. Examples demonstrating the utility of these hybrid systems as advanced DDS are discussed, highlighting their potential for precise drug release alongside theranostic capabilities by combining therapy with imaging. Despite the challenges in design, synthesis, and biological applications, thermoresponsive polymer‐inorganic hybrids hold immense promise for transforming drug delivery and biomedical innovations.


  • Open Access

    A flexible cystoscopy device prototype for mechanical tissue ablation based on micro-scale hydrodynamic cavitation: Ex vivo and in vivo studies

    by Ezgi Kestek, Ünal Akar, Seyedali Seyedmirzaei Sarraf, Ozcan Kanbur, Ufuk Gorkem Kirabali, Hande Eda Sutova, Morteza Ghorbani, Ozlem Kutlu, Huseyin Uvet, Asiye Isin Dogan Ekici, et al.


  • Open Access

    Autophagy-related mechanisms for treatment of multiple myeloma

    by Gül Kozalak, Ali Koşar

    Multiple myeloma (MM) is a type of hematological cancer that occurs when B cells become malignant. Various drugs such as proteasome inhibitors, immunomodulators, and compounds that cause DNA damage can be used in the treatment of MM. Autophagy, a type 2 cell death mechanism, plays a crucial role in determining the fate of B cells, either promoting their survival or inducing cell death. Therefore, autophagy can either facilitate the progression or hinder the treatment of MM disease. In this review, autophagy mechanisms that may be effective in MM cells were covered and evaluated within the contexts of unfolded protein response (UPR), bone marrow microenvironment (BMME), drug resistance, hypoxia, DNA repair and transcriptional regulation, and apoptosis. The genes that are effective in each mechanism and research efforts on this subject were discussed in detail. Signaling pathways targeted by new drugs to benefit from autophagy in MM disease were covered. The efficacy of drugs that regulate autophagy in MM was examined, and clinical trials on this subject were included. Consequently, among the autophagy mechanisms that are effective in MM, the most suitable ones to be used in the treatment were expressed. The importance of 3D models and microfluidic systems for the discovery of new drugs for autophagy and personalized treatment was emphasized. Ultimately, this review aims to provide a comprehensive overview of MM disease, encompassing autophagy mechanisms, drugs, clinical studies, and further studies.


  • Open Access

    Review on Bortezomib Resistance in Multiple Myeloma and Potential Role of Emerging Technologies

    by Gül Kozalak, İsmail Bütün, Erçil Toyran, Ali Koşar

    Multiple myeloma is a hematological cancer type. For its treatment, Bortezomib has been widely used. However, drug resistance to this effective chemotherapeutic has been developed for various reasons. 2D cell cultures and animal models have failed to understand the MM disease and Bortezomib resistance. It is therefore essential to utilize new technologies to reveal a complete molecular profile of the disease. In this review, we in-depth examined the possible molecular mechanisms that cause Bortezomib resistance and specifically addressed MM and Bortezomib resistance. Moreover, we also included the use of nanoparticles, 3D culture methods, microfluidics, and organ-on-chip devices in multiple myeloma. We also discussed whether the emerging technology offers the necessary tools to understand and prevent Bortezomib resistance in multiple myeloma. Despite the ongoing research activities on MM, the related studies cannot provide a complete summary of MM. Nanoparticle and 3D culturing have been frequently used to understand MM disease and Bortezomib resistance. However, the number of microfluidic devices for this application is insufficient. By combining siRNA/miRNA technologies with microfluidic devices, a complete molecular genetic profile of MM disease could be revealed. Microfluidic chips should be used clinically in personal therapy and point-of-care applications. At least with Bortezomib microneedles, it could be ensured that MM patients can go through the treatment process more painlessly. This way, MM can be switched to the curable cancer type list, and Bortezomib can be targeted for its treatment with fewer side effects.