Browsing by Subject "Biomimetic"

Now showing 1 - 6 of 6

Open Access
Advances in biomimetic systems for molecular recognition and biosensing
(MDPI Multidisciplinary Digital Publishing Institute, 2020-05) Saylan, Y.; Erdem, Özgecan; İnci, Fatih; Denizli, A.
Understanding the fundamentals of natural design, structure, and function has pushed the limits of current knowledge and has enabled us to transfer knowledge from the bench to the market as a product. In particular, biomimicry—one of the crucial strategies in this respect—has allowed researchers to tackle major challenges in the disciplines of engineering, biology, physics, materials science, and medicine. It has an enormous impact on these fields with pivotal applications, which are not limited to the applications of biocompatible tooth implants, programmable drug delivery systems, biocompatible tissue scaffolds, organ-on-a-chip systems, wearable platforms, molecularly imprinted polymers (MIPs), and smart biosensors. Among them, MIPs provide a versatile strategy to imitate the procedure of molecular recognition precisely, creating structural fingerprint replicas of molecules for biorecognition studies. Owing to their affordability, easy-to-fabricate/use features, stability, specificity, and multiplexing capabilities, host-guest recognition systems have largely benefitted from the MIP strategy. This review article is structured with four major points: (i) determining the requirement of biomimetic systems and denoting multiple examples in this manner; (ii) introducing the molecular imprinting method and reviewing recent literature to elaborate the power and impact of MIPs on a variety of scientific and industrial fields; (iii) exemplifying the MIP-integrated systems, i.e., chromatographic systems, lab-on-a-chip systems, and sensor systems; and (iv) closing remarks.
Open Access
Biomimetic cell membrane-coated poly(lactic-co-glycolic acid) nanoparticles for biomedical applications
(John Wiley & Sons, Inc., 2022-11-02) Jan, N.; Madni, A.; Khan, S.; Shah, H.; Akram, F.; Khan, A.; Ertas, D.; Bostanudin, M. F.; Contag, C. H.; Ashammakhi, N.; Ertaş, Yavuz Nuri
Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are commonly used for drug delivery because of their favored biocompatibility and suitability for sustained and controlled drug release. To prolong NP circulation time, enable target-specific drug delivery and overcome physiological barriers, NPs camouflaged in cell membranes have been developed and evaluated to improve drug delivery. Here, we discuss recent advances in cell membrane-coated PLGA NPs, their preparation methods, and their application to cancer therapy, management of inflammation, treatment of cardiovascular disease and control of infection. We address the current challenges and highlight future research directions needed for effective use of cell membrane-camouflaged NPs
Open Access
Biomimetic self-assembled peptide nanofibers for bone regeneration
(2012) Kocabey, Samet
Self-assembled peptide nanofibers are exploited in regenerative medicine applications due to their versatile, biofunctional and extracellular-matrixresembling structures. These properties provide peptide nanofibers with osteoinductive and osteoconductive behaviors for bone regeneration applications through several approaches. In this thesis, two different approaches were discussed, which were developed to induce bone regeneration and mineralization including extracellular matrix mimicking peptide nanofibers based 2-D gel formation and surface functionalization of titanium implants. For this purpose, we designed glycosaminoglycan-mimetic peptide nanofibers inspired by chemical structure of glycosaminoglycans present in the bone extracellular matrix. We demonstrated that glycosaminoglycan-mimetic peptide nanofibers interact with BMP-2, a critical growth factor for osteogenic activity. Glycosaminoglycan-mimicking ability of the peptide nanofibers and their interaction with BMP-2 promoted osteogenic activity of and mineralization by osteoblastic cells. ALP activity, Alizarin Red Staining and EDAX spectroscopy indicated efficacy of the peptide nanofibers for inducing mineralization. We also developed a hybrid osteoconductive system for titanium biomedical implants inspired by mussel adhesion mechanism in order to overcome bone tissue integration problems. For this purpose, Dopa conjugated peptide nanofiber coating was used along with bioactive peptide sequences for osteogenic activity to enhance osseointegration of titanium surface. Dopamediated immobilization of osteogenic peptide nanofibers on titanium surfaces created an osteoconductive interface between osteoblast-like cells and inhibited adhesion and viability of soft tissue forming fibroblasts compared to the uncoated titanium substrate. In summary, osteoinductive and osteoconductive self-assembled peptide nanofibers were developed to promote osteogenic activity and mineralization of osteogenic cells. These bioactive nanofibers provide a potent platform in clinical applications of bone tissue engineering.
Open Access
Small functional groups presented on peptide nanofibers for determining fate of rat mesenchymal stem cells
(2014) Yaşa, Öncay
Glycosaminoglycans (GAGs) are negatively-charged, unbranched polysaccharides that play important roles in various biological processes and are vital for the regeneration of damaged tissues. Like other natural extracellular matrix components, glycosaminoglycans and proteoglycans show considerable variation in local concentration and chemical composition depending on tissue type. They are found in various connective tissues, including bone, cartilage and fat, and display strong water-binding capacity due to their negative charges. Mechanical characters of GAGs are heavily influenced by the degree and pattern of sulfation, which may greatly alter their viscoelasticity and physiological functions. Variations in GAG sulfation patterns are created principally through extracellular matrix modeling. Due to their extracellular matrix-organizing abilities, glycosaminoglycans are promising biomacromolecules for the design of new bioactive materials for tissue engineering and tissue reconstruction applications. In this study, we functionalized peptide amphiphile molecules with carboxylate and sulfonate groups to develop nanofibrous networks displaying a range of chemical patterns, and evaluated the effect of the chemical groups over the differentiation fate of rat mesenchymal stem cells. We demonstrate that higher sulfonate-to-glucose ratios are associated with adipogenesis, while higher carboxylate-to-glucose ratios resulted in chondrogenic and osteogenic differentiation of the rat mesenchymal stem cells.
Open Access
Template-directed synthesis of silica nanotubes for explosive detection
(American Chemical Society, 2011) Yildirim, A.; Acar, H.; Erkal, T. S.; Bayındır, Mehmet; Güler, Mustafa O.
Fluorescent porous organic-inorganic thin films are of interest of explosive detection because of their vapor phase fluorescence quenching property. In this work, we synthesized fluorescent silica nanotubes using a biomineralization process through self-assembled peptidic nanostructures. We designed and synthesized an amyloid-like peptide self-assembling into nanofibers to be used as a template for silica nanotube formation. The amine groups on the peptide nanofibrous system were used for nucleation of silica nanostructures. Silica nanotubes were used to prepare highly porous surfaces, and they were doped with a fluorescent dye by physical adsorption for explosive sensing. These porous surfaces exhibited fast, sensitive, and highly selective fluorescence quenching against nitro-explosive vapors. The materials developed in this work have vast potential in sensing applications due to enhanced surface area. © 2011 American Chemical Society.
Open Access
Three dimensional glycosaminoglycan mimetic peptide amphiphile hydrogels for regenerative medicine applications
(2015-05) Tümtaş, Yasin
Defects and impairments of tissues or organs affect millions of people, resulting in considerable losses in workforce and life quality. The treatment of major tissue injuries requires the development of advanced medical techniques that enhance the natural repair processes of the human body. Novel biomaterials can modulate the repair of organs and tissues by providing a suitable environment for the recruitment, proliferation and differentiation of stem and progenitor cells, allowing the recovery of degenerated or otherwise nonfunctional tissues. Peptide amphiphiles (PAs) serve as model biomaterials due to their capacity for self-assembly, which allows peptide monomers to form complex networks that approximate the structure and function of the natural extracellular matrix. Peptide networks can be further modified by the attachment of various epitopes and functional groups, allowing these materials to present bioactive signals to surrounding cells. Glycosaminoglycans (GAGs) are negatively charged, unbranched polysaccharides that constitute a substantial part of the ECM in various tissues and play an important role in maintaining tissue integrity. Therefore, mimicking GAGs presents a suitable means for modulating cell behavior and especially lineage commitment in stem cells. In this work, I describe the design and synthesis of several bioactive, three dimensional (3D) GAG-mimetic peptide amphiphile hydrogels for in vitro stem cell differentiation and in vivo pancreatic islet transplantation. In Chapter 1, I detail the extracellular environment of tissues and the importance of GAGs in maintaining cell and tissue function. In Chapter 2, I describe the in vitro experiments involving the effects of sulfonation and the presence of glucose units on the differentiation of mesenchymal stem cells. In Chapter 3, I utilize a heparin-mimetic PA to increase the survival of pancreatic islets transplanted into the rat omentum, and demonstrate that increased angiogenesis results in enhanced survival. Lastly, in Chapter 4, I summarize my results and describe the course of future experiments for the artificial regeneration of tissues through peptide amphiphile networks.