scholarly journals The development of crosslinked gelatin thin films as controlled release matrices

2021 ◽  
Author(s):  
Alireza Abbasi
Keyword(s):  
Thin Films ◽  
Mathematical Model ◽  
Controlled Release ◽  
Release Kinetics ◽  
Fluorescent Marker ◽  
Force Microscopy ◽  
Standard Glass ◽  
Atomic Force ◽  
Gelatin Films ◽  
Glass Slides

The aim of this thesis was to develop gelatin-based thin films that may be used as matrices for the controlled release of bioactive compounds. There were three objectives to this research: i) develop a method to generate the thin films ii) experimentally quantify the release of a fluorescent marker from these films, and iii) implement a mathematical model to characterize the release of the fluorescent marker. To achieve the first objective, a novel method of developing thin films was implemented where sub-micron thickness films affixed to standard glass slides were crosslinked with genipin, a naturally-occurring fixative. Gel thickness measured using atomic force microscopy (AFM) varied from 350 to 650 nm irrespective of the concentration of genifin added. AFM-based surface roughness decreased with increasing genipin concentration. Release behavior of a fluorescent marker from the thin films demonstrated a strong influence of genipin concentration on release kinetics, with greater genipin leading to slower release. A mathematical model for the water transport into, and fluorescent marker release from, the genipin-crosslinked gelatin films was developed and successfully implemented with both the water ingress (swelling) and marker release being effectively characterized by the model.

scholarly journals The development of crosslinked gelatin thin films as controlled release matrices

2021 ◽  
Author(s):  
Alireza Abbasi
Keyword(s):  
Thin Films ◽  
Mathematical Model ◽  
Controlled Release ◽  
Release Kinetics ◽  
Fluorescent Marker ◽  
Force Microscopy ◽  
Standard Glass ◽  
Atomic Force ◽  
Gelatin Films ◽  
Glass Slides

The aim of this thesis was to develop gelatin-based thin films that may be used as matrices for the controlled release of bioactive compounds. There were three objectives to this research: i) develop a method to generate the thin films ii) experimentally quantify the release of a fluorescent marker from these films, and iii) implement a mathematical model to characterize the release of the fluorescent marker. To achieve the first objective, a novel method of developing thin films was implemented where sub-micron thickness films affixed to standard glass slides were crosslinked with genipin, a naturally-occurring fixative. Gel thickness measured using atomic force microscopy (AFM) varied from 350 to 650 nm irrespective of the concentration of genifin added. AFM-based surface roughness decreased with increasing genipin concentration. Release behavior of a fluorescent marker from the thin films demonstrated a strong influence of genipin concentration on release kinetics, with greater genipin leading to slower release. A mathematical model for the water transport into, and fluorescent marker release from, the genipin-crosslinked gelatin films was developed and successfully implemented with both the water ingress (swelling) and marker release being effectively characterized by the model.

Atomic force microscopy of in situ deformed nickel thin films

1999 ◽  
Vol 353 (1-2) ◽  
pp. 194-200 ◽  
Author(s):  
C. Coupeau ◽  
J.F. Naud ◽  
F. Cleymand ◽  
P. Goudeau ◽  
J. Grilhé
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Force Microscopy ◽  
Nickel Thin Films ◽  
Atomic Force

scholarly journals Topological, chemical and electro-optical characteristics of riboflavin-doped artificial and natural DNA thin films

2018 ◽  
Vol 5 (2) ◽  
pp. 171179 ◽  
Author(s):  
Bramaramba Gnapareddy ◽  
Sreekantha Reddy Dugasani ◽  
Junyoung Son ◽  
Sung Ha Park
Keyword(s):  
Thin Films ◽  
Photonic Devices ◽  
Uv Absorption ◽  
Optical Characteristics ◽  
Force Microscopy ◽  
Atomic Force ◽  
Functionalized Nanomaterials ◽  
Amorphous Structures ◽  
The Fourier Transform ◽  
Immense Potential

DNA is considered as a useful building bio-material, and it serves as an efficient template to align functionalized nanomaterials. Riboflavin (RF)-doped synthetic double-crossover DNA (DX-DNA) lattices and natural salmon DNA (SDNA) thin films were constructed using substrate-assisted growth and drop-casting methods, respectively, and their topological, chemical and electro-optical characteristics were evaluated. The critical doping concentrations of RF ([RF] C , approx. 5 mM) at given concentrations of DX-DNA and SDNA were obtained by observing the phase transition (from crystalline to amorphous structures) of DX-DNA and precipitation of SDNA in solution above [RF] C . [RF] C are verified by analysing the atomic force microscopy images for DX-DNA and current, absorbance and photoluminescence (PL) for SDNA. We study the physical characteristics of RF-embedded SDNA thin films, using the Fourier transform infrared spectrum to understand the interaction between the RF and DNA molecules, current to evaluate the conductance, absorption to understand the RF binding to the DNA and PL to analyse the energy transfer between the RF and DNA. The current and UV absorption band of SDNA thin films decrease up to [RF] C followed by an increase above [RF] C . By contrast, the PL intensity illustrates the reverse trend, as compared to the current and UV absorption behaviour as a function of the varying [RF]. Owing to the intense PL characteristic of RF, the DNA lattices and thin films with RF might offer immense potential to develop efficient bio-sensors and useful bio-photonic devices.

Nanocrystalline Solutions as Precursors to The Spray Deposition of Cdte Thin Films

1995 ◽  
Vol 382 ◽  
Author(s):  
Martin Pehnt ◽  
Douglas L. Schulz ◽  
Calvin J. Curtis ◽  
Helio R. Moutinho ◽  
Amy Swartzlander ◽  
...  
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Grain Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Cdte Nanoparticles ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Cdte Thin Films

ABSTRACTIn this article we report the first nanoparticle-derived route to smooth, dense, phase-pure CdTe thin films. Capped CdTe nanoparticles were prepared by injection of a mixture of Cd(CH3)2, (n-C8H17)3 PTe and (n-C8H17)3P into (n-C8H17)3PO at elevated temperatures. The resultant nanoparticles 32-45 Å in diameter were characterized by x-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy, thermogravimetric analysis and energy dispersive x-ray spectroscopy. CdTe thin film deposition was accomplished by dissolving CdTe nanoparticles in butanol and then spraying the solution onto SnO2-coated glass substrates at variable susceptor temperatures. Smooth and dense CdTe thin films were obtained using growth temperatures approximately 200 °C less than conventional spray pyrolysis approaches. CdTe films were characterized by x-ray diffraction, UV-Vis spectroscopy, atomic force microscopy, and Auger electron spectroscopy. An increase in crystallinity and average grain size as determined by x-ray diffraction was noted as growth temperature was increased from 240 to 300 °C. This temperature dependence of film grain size was further confirmed by atomic force microscopy with no remnant nanocrystalline morphological features detected. UV-Vis characterization of the CdTe thin films revealed a gradual decrease of the band gap (i.e., elimination of nanocrystalline CdTe phase) as the growth temperature was increased with bulk CdTe optical properties observed for films grown at 300 °C.

Studies of Nanomechanical Properties of Pulsed Laser Deposited NbN films on Si Using Nanoindentation

2012 ◽  
Vol 1424 ◽  
Author(s):  
M. A. Mamun ◽  
A. H. Farha ◽  
Y. Ufuktepe ◽  
H. E. Elsayed-Ali ◽  
A. A. Elmustafa
Keyword(s):  
Thin Films ◽  
Pulsed Laser ◽  
Niobium Nitride ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wide Range ◽  
Pile Up ◽  
Average Modulus

ABSTRACTNanomechanical and structural properties of pulsed laser deposited niobium nitride thin films were investigated using X-ray diffraction, atomic force microscopy, and nanoindentation. NbN film reveals cubic δ-NbN structure with the corresponding diffraction peaks from the (111), (200), and (220) planes. The NbN thin films depict highly granular structure, with a wide range of grain sizes that range from 15-40 nm with an average surface roughness of 6 nm. The average modulus of the film is 420±60 GPa, whereas for the substrate the average modulus is 180 GPa, which is considered higher than the average modulus for Si reported in the literature due to pile-up. The hardness of the film increases from an average of 12 GPa for deep indents (Si substrate) measured using XP CSM and load control (LC) modes to an average of 25 GPa measured using the DCM II head in CSM and LC modules. The average hardness of the Si substrate is 12 GPa.

scholarly journals The Physicochemical and Antibacterial Properties of Chitosan-Based Materials Modified with Phenolic Acids Irradiated by UVC Light

2021 ◽  
Vol 22 (12) ◽  
pp. 6472
Author(s):  
Beata Kaczmarek-Szczepańska ◽  
Marcin Wekwejt ◽  
Olha Mazur ◽  
Lidia Zasada ◽  
Anna Pałubicka ◽  
...  
Keyword(s):  
Thin Films ◽  
Antimicrobial Activity ◽  
Ferulic Acid ◽  
Phenolic Acid ◽  
Food Packaging ◽  
Antibacterial Properties ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After

This paper concerns the physicochemical properties of chitosan/phenolic acid thin films irradiated by ultraviolet radiation with wavelengths between 200 and 290 nm (UVC) light. We investigated the preparation and characterization of thin films based on chitosan (CTS) with tannic (TA), caffeic (CA) and ferulic acid (FA) addition as potential food-packaging materials. Such materials were then exposed to the UVC light (254 nm) for 1 and 2 h to perform the sterilization process. Different properties of thin films before and after irradiation were determined by various methods such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimeter (DSC), mechanical properties and by the surface free energy determination. Moreover, the antimicrobial activity of the films and their potential to reduce the risk of contamination was assessed. The results showed that the phenolic acid improving properties of chitosan-based films, short UVC radiation may be used as sterilization method for those films, and also that the addition of ferulic acid obtains effective antimicrobial activity, which have great benefit for food packing applications.

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