Browsing by Subject "Green chemistry"

Now showing 1 - 2 of 2

Open Access
Eco-friendly fabrication of plasmonically active substrates based on end-grafted poly(ethylene glycol) layers
(American Chemical Society, 2019) Karabel Öcal, S.; Pekdemir, S.; Serhatlıoğlu, Murat; İpekçi, H. H.; Şahmetlioğlu, E.; Narin, İ.; Duman, F.; Elbüken, Çağlar; Demirel, G.; Önses, Mustafa Serdar
We report completely sustainable processes and materials for inexpensive and scalable fabrication of plasmonically active solid substrates, which are critical for emerging applications in sensing, catalysis, and metasurfaces. Our approach involves grafting of poly(ethylene glycol) (PEG) onto silicon oxide terminated solid substrates using all-water based processing leading to an ultrathin (12 nm) and smooth (roughness of ∼1 nm) functional layer. The resulting surfaces facilitate robust and effective immobilization of gold nanoparticles (NPs) with a density that is superior to the organic solvent based processing. This new process achieves size dependent assembly of the citrate-stabilized gold NPs resulting in high plasmonic activity in surface-enhanced Raman scattering (SERS). The use of leaf extracts derived from Quercus pubescens as a reducing and stabilizing agent allowed for green synthesis of gold NPs with an average diameter of 25.6 ± 11.1 nm. The assembly of the green synthesized gold NPs on all-water processed PEG grafted layers enabled a fully sustainable route for fabrication of plasmonically active solid substrates. The resulting substrates exhibited high SERS response over the entire (∼1 cm2) substrate surface with an analytical enhancement factor of 9.48 × 104 for the probe molecule rhodamine 6G under 532 nm laser excitation. A microfluidic device was also constructed on the fabricated platform for SERS mediated simultaneous detection of two nonsteroidal anti-inflammatory drugs, dexketoprofen and ibuprofen, which are widely used in human medicine and present as contaminants in wastewater. The biocompatibility of PEG together with all-water based processing overcome the need for waste management and ventilation of the working place enabling cost and energy efficient, environmentally benign fabrication of plasmonic devices.
Open Access
Microfluidic vs. batch synthesis of fluorescent poly(GMA-co-EGDMA) micro/nanoparticles for biomedical applications
(Springer Nature, 2024-09-25) Kılınçlı, Betül; Çınar, Ayşe Duru; Çetin, Barbaros; Kibar, Güneş
Fluorescent particles play a crucial role in nanomedicine and biological applications such as imaging, diagnostic tools, drug delivery, biosensing, multimodal imaging, and theranostics. This report presents a novel synthesis method and comparative study for synthesizing fluorescent particles in microfluidic continuous and batch-type reactors. Glycidyl methacrylate (GMA) and ethylene glycol dimethyl acrylate (EGDMA) are well-known monomers for synthesizing functional particles for biomedical applications. Several methods exist to obtain fluorescent poly(GMA-co-EGDMA) (p(GMA-EGDMA))particles through various polymerization techniques. Unlike existing methods, we developed a green approach for synthesizing fluorescent p(GMA-EGDMA) particles via UV-initiated one-step emulsion polymerization by comparing microfluidic and batch synthesis. Moreover, as a fluorescent dye, fluorescein isothiocyanate (FITC) was directly incorporated with p(GMA-EGDMA) particles at various concentrations to achieve tunable fluorescent functionality. While the batch synthesis resulted in polydisperse fluorescent p(GMA-EGDMA)microparticles with spherical shapes ranging from 25 μm to 1.0 μm in size, the microfluidic synthesis produced nonspherical nanoparticles. Fluorescent FITC@p(GMA-EGDMA) particles were characterized by scanning electron microscope (SEM), fluorescent microscope, and Fourier-transform infrared spectroscopy (FTIR). The synthesized particles have potential for fluorescence imaging applications, specifically bio-detection in array systems.