SPR Method Research Articles

Residence time prediction in magnetically controlled biomolecular local rebinding-dissociation kinetics

The residence time of drug-target conjugates is a critical factor in drug screening and efficacy prediction. The local rebinding-dissociation kinetics gives insights into in-vivo drug-target interactions. A magnetic torque system (MTS) is designed to observe rebinding-dissociation kinetics for predicting residence time. The system utilizes an alternating magnetic field (AMF) to manipulate the magnetization motion of magnetically labeled biomolecules and the forces acting upon biomolecular bonds. The motion, sensed by a quartz crystal microbalance (QCM), reflects biomolecular interactions occurring at the particle surface. Meanwhile, the motion facilitates the separation of dissociated molecules from the surface, thereby obviating the necessity for fixed and mobile phases in common kinetics observations. The constant and static solution environment minimizes reagent consumption. The MTS was utilized to observe the local rebinding-dissociation of antibodies (PAB and MAB) to magnetic beads (MB) and to HER2 receptors. The residence times recorded by the MTS were larger than the results obtained via SPR method, due to the occurrences of rebinding-dissociation kinetics. Interaction behaviours can be meticulously regulated for varying affinities by modulating the intensity of magnetic field. A high intensity field (400 Oe) was applied for strong binding between antibody-MB (biotin-streptavidin), and a low intensity field (300 Oe) was applied for weak antigen-antibody interactions. An increase in AMF strength enhanced dissociation, with a shift from 300 Oe to 400 Oe resulting in a 1 ∼ 4-fold reduction in residence time. Overall, the MTS provides an interactive and customizable perspective on kinetics observations.

Abstract 3315: Preclinical studies of TSN1611, a potent, selective, and orally bioavailable KRASG12D inhibitor

Abstract Background: KRAS mutations are the most frequently encountered driver oncogene, involved in ~25% of all human cancers [1,2]. KRASG12D is the predominant KRAS mutation isoform, detected in approximately 35% of pancreatic cancer, 13% of colorectal cancer, and 5% of NSCLC [3]. Compared to KRASG12C, targeting KRASG12D has proven to be more challenging since the target protein lacks a reactive amino acid residue for irreversible inhibitory modification by a ligand. Herein, we disclose TSN1611, a potent and selective KRASG12D inhibitor, which possesses favorable oral PK profiles and demonstrates significant in vitro and in vivo anti-tumor activity in various KRASG12D-mutant models. Method: Biochemical HTRF assay was used to measure the inhibition of TSN1611 to both GDP-bound and GTP-bound state of KRASG12D. Biophysical SPR method was used to directly measure the binding of TSN1611 to GDP-bound KRASG12D and KRASWT. Cell based activities were evaluated in a series of in vitro cell proliferation assay utilizing Ba/F3 cells engineered with KRASG12D or non-KRASG12D mutations and tumor cell lines harboring KRASG12D mutation. Human cancer cell-derived xenograft models of HPAC (pancreatic) and GP2D (colorectal) were used to evaluate its in vivo antitumor effect. in vitro and in vivo PK studies were performed in mouse, rat, and dog. Systematic nonclinical safety evaluations, including safety panel screen testing, safety pharmacology studies, and repeat-dose toxicity studies were carried out to assess its preliminary toxicity profile. Results: TSN1611 inhibited both active (GTP-bound) and inactive (GDP-bound) forms of KRASG12D protein at IC50 1.23 and 1.49 nM, respectively; the KD value of its direct binding to KRASG12D protein is 1.93 pM in SPR assay. TSN1611 demonstrated potent anti-proliferation activity against several tumor cell lines harboring KRASG12D mutation, and excellent selectivity over cells of NRAS, HRAS, and other KRAS isoforms. It also showed dose-dependent anti-tumor efficacy in GP2D and HPAC models. Mechanism of action studies concluded that the antitumor effect of TSN1611 is resulted from its effective inhibition of KRAS signaling pathway. Oral bioavailability and safety profile across multiple species supported its further development. Conclusion: TSN1611 is a selective KRASG12D inhibitor. It exhibited excellent selectivity and activity both in vitro and in vivo; it demonstrated favorable physicochemical properties, oral PK profiles, and brain penetration potential; it also showed acceptable margins of safety. The preclinical data supports further development. Pending regulatory submission and review, the phase I/II study is planned to start in H1 of 2024.

Using surface plasmon resonance, capillary electrophoresis and diffusion-ordered NMR spectroscopy to study drug release kinetics

Nanomedicines, including polymer nanocarriers with controlled drug release, are considered next-generation therapeutics with advanced therapeutic properties and reduced side effects. To develop safe and efficient nanomedicines, it is crucial to precisely determine the drug release kinetics. Herein, we present application of analytical methods, i.e., surface plasmon resonance biosensor technology (SPR), capillary electrophoresis, and 1H diffusion-ordered nuclear magnetic resonance spectroscopy, which were innovatively applied for drug release determination. The methods were optimised to quantify the pH-triggered release of three structurally different drugs from a polymer carrier. The suitability of these methods for drug release characterisation was evaluated and compared using several parameters including applicability for diverse samples, the biological relevance of the experimental setup, method complexity, and the analysis outcome. The SPR method was the most universal method for the evaluation of diverse drug molecule release allowing continuous observation in the flow-through setting and requiring a small amount of sample.

The validation of artificial anti-monkeypox antibodies by in silico and experimental approaches.

As a result of smallpox immunization programs that ended more than 40 years ago, a significant portion of the world's population is not immune. Moreover, due to the lack of anti-monkeypox drugs and vaccines against monkeypox, the spread of this virus may be the beginning of another challenge. In this study, novel antibodies against monkeypox virus were modeled based on a heavy chain of human antibody and a small peptide fragment. Docking of modeled antibodies with C19L protein showed the range of docking energy, and root-mean-square deviation (RMSD) was from -124 to -154 kcal/mL and 4-6 angstrom, respectively. Also, docking of modeled antibodies-C19L complex with gamma Fc receptor type I illustrated the range of docking energy, and RMSD was from -132 to -155 kcal/ml and 5-7 angstrom, respectively. Moreover, molecular dynamics simulation showed that antibody 62 had the highest stability with the lowest energy level and RMSD. Interestingly, no modeled antibodies had immunogenicity, allergenicity, and toxicity. Although all of them had good stability, only antibodies 25, 28, 54, and 62 had a half-life of >10 h. Moreover, the interaction between C19L protein and anti-C19L antibodies (wild-type and synthetic) was evaluated by the SPR method. We found that KD in synthetic antibodies was lower than wild antibody. In terms of δH°, TδS°, and δG°, the results were consistent with binding parameters. Here, the lowest value of thermodynamic parameters was obtained for antibody 62. These data show that the synthetic antibodies, especially antibody 62, had a higher affinity than the wild-type antibody.

Precipitation and recovery of lysozyme denatured by urea and guanidine hydrochloride using anionic surfactant and acetone

The surfactant precipitation and recovery method (SPR method) consist of a precipitation step, that is precipitation of protein-surfactant complex by the addition of aqueous surfactant solution to aqueous protein solution, and a recovery step, that is dissolution of precipitate in polar organic solvent and protein recovery by addition of trace amount of aqueous salt solution. When the denaturant was not included, the precipitation ratio of lysozyme increased as the AOT/lysozyme molar ratio increased, and after reaching 100%, the precipitation ratio decreased due to the redissolution of the precipitation. It was shown that lysozyme denatured by urea and GuHCl can be recovered by the SPR method. Lysozyme denatured with urea had a precipitation ratio and recovery ratio of almost 100% up to a urea concentration of 4 kmol/m3 at an AOT/lysozyme molar ratio of 28.6. As the urea concentration increased, the precipitation ratio and the recovery ratio decreased. Lysozyme denatured with GuHCl had a precipitation ratio and recovery ratio of about 75% at an AOT/lysozyme molar ratio of 71.5 and a GuHCl concentration of 0.6 kmol/m3. The specific activity and the secondary conformation of the recovered lysozyme were confirmed to be almost the same as those of the native lysozyme by measuring the enzyme activity and CD spectrum. It was shown that lysozyme denatured with urea and GuHCl can be recovered by the SPR method as lysozyme has native properties.

Optimization health service management platform based on big data knowledge management

In order to improve the management effect of community health service, this paper uses big data knowledge management to study the community health service management platform. This paper studies the basic theory of error estimation method, as well as the stress smoothing process and method of restoring stress. Moreover, this paper analyzes the theory and steps of constructing smooth stress based on SPR method, and emphasizes the problem that errors are prone to occur in the construction process. In addition, this paper uses MATLAB to write an error estimation module, uses the average method around the point to calculate the smoothing stress, and builds a system based on the actual situation of community health service management. The analysis shows that the community elderly sports health service management platform based on big data knowledge management proposed in this paper can effectively improve the effect of community health management.

Data requirements for operating model of harvest strategy for yellowfin tuna fisheries in North Maluku Waters

This Study focused on tuna handline fisheries in Morotai Island, North Maluku. Yellowfin tuna fisheries have great potential economic value. However, the high level of exploitation by small-scale fisheries in coastal waters is feared to disrupt the sustainability of tuna resources therefore, a better management approach is needed, known as a harvest strategy, based on the use of appropriate data and a strong operating model. Indonesia’s government initiated to development of the harvest strategies to manage tuna resources within Indonesia’s archipelagic waters (FMAs 713, 714, dan 715) as a priority action of the National Tuna Management Plan (NTMP). The implementation of the strategy requires adequate data and completeness of instruments. This research tried to identify the adequacy and availability of harvest strategy data and determine yellowfin resource status with LB-SPR. The case studies demonstrate the utility of scientific monitoring data to track trends in the abundance of adult fish without requiring complex stock assessment models through gap analysis. The adequate data harvest strategy was used to condition prototype operating models for testing preliminary harvest strategies through better OMs and MSE. The results showed that the adequacy of the HS data had a gap of 1.56 with an adjustable rate of 63% or not up to standard. The level of utilization of yellowfin tuna resources using the SPR method leads to overfishing.

A new multigene HCIQ subfamily from the sea anemone Heteractis crispa encodes Kunitz-peptides exhibiting neuroprotective activity against 6-hydroxydopamine

The Kunitz/BPTI-type peptides are ubiquitous in numerous organisms including marine venomous animals. The peptides demonstrate various biological activities and therefore they are the subject of a number of investigations. We have discovered a new HCIQ subfamily belonging to recently described multigene HCGS family of Heteractis crispa Kunitz-peptides. The uniqueness of this subfamily is that the HCIQ precursors contain a propeptide terminating in Lys-Arg (endopeptidase cleavage site) the same as in the neuro- and cytotoxin ones. Moreover, the HCIQ genes contain two introns in contrast to HCGS genes with one intron. As a result of Sanger and amplicon deep sequencings, 24 HCIQ isoforms were revealed. The recombinant peptides for the most prevalent isoform (HCIQ2c1) and for the isoform with the rare substitution Gly17Glu (HCIQ4c7) were obtained. They can inhibit trypsin with Ki 5.2 × 10−8 M and Ki 1.9 × 10−7 M, respectively, and interact with some serine proteinases including inflammatory ones according to the SPR method. For the first time, Kunitz-peptides have shown to significantly increase neuroblastoma cell viability in an in vitro 6-OHDA-induced neurotoxicity model being a consequence of an effective decrease of ROS level in the cells.

The use surface plasmon resonance to determine the optical parameters of UV-adhesive and control polymerization process

Background Ultraviolet adhesives are widely used in the manufacture of precision optical devices It is known that adding fillers to the glue reduces shrinkage after polymerization reduces internal stresses improves the reliability of the connection and also allows you to control the optical properties of the connecting layer By varying the amount and composition of the filler you can change the refractive index of the compound as well as improve the process ability of the compound due to faster polymerization nbsp Material and methods To measure optical parameters of the studied samples we used the following devices spectrometer Plasmon spectrophotometer Fluorotestnano S spectrophotometer UNICO UV VIS As a source of UV radiation we used semiconductor LED with the mean wavelength in its spectrum nm As the objects for measurements we used three samples and each one represented the three layered structure glass ndash adhesive ndash glass and separately three respective adhesives All the glass elements of these samples were plates with the thickness mm and dimensions times mm from the glass with the refractive index n with regard to vacuum The sample differed between each other by composition of adhesives nbsp Results The reflective index for each glue was defined The speed of glue polymerization was corresponded to difference on a result changes the coefficient of reflection too The highest velocity of polymerization was observed for the adhesive arb un min the lowest one ndash for the adhesive arb un min and adhesive arb un min Thus the polymerization velocity of the adhesive is times higher than that of the adhesive and practically times higher than for the adhesive adhesives and are polymerized more uniformly over the whole sample depth The reflection coefficient at the minimum SPR was measured This characteristic corresponds to the absorption of the glue It is shown that the adhesive composition No has the greatest absorption nbsp Conclusion The obtained results show that the SPR method is informative and can be applied for investigations and optimization of UV adhesive composition Introduction of organosilicon acrylates with high dispersion as impurities in these adhesives enables to increase the velocity of adhesive polymerization

Biosensor-Surface Plasmon Resonance: Label-Free Method for Investigation of Small Molecule-Quadruplex Nucleic Acid Interactions.

Biosensor-surface plasmon resonance (SPR) technology is now well established as a quantitative approach for the study of nucleic acid interactions in real time, without the need for labeling any components of the interaction. The method provides real-time equilibrium and kinetic characterization for quadruplex DNA interactions and requires small amounts of materials and no external probe. A detailed protocol for quadruplex-DNA interaction analyses with a variety of binding molecules using biosensor-SPR methods is presented. Explanations of the SPR method with basic fundamentals for use and analysis of results are described with recommendations on the preparation of the SPR instrument, sensor chips, and samples. Details of experimental design, quantitative and qualitative data analyses, and presentation are described. Some specific examples of small molecule-DNA quadruplex interactions are presented with results evaluated by both kinetic and steady-state SPR methods.

Infrared Problem in Cold Atom Quantum Physisorption on 2D Materials

Results from four different approximations to the phonon-assisted quantum adsorption rate for cold atoms on a 2D material are compared and contrasted: (1) a loop expansion (LE) based on the atom-phonon coupling, (2) non-crossing approximation (NCA), (3) independent boson model approximation (IBMA), and (4) a leading-order soft-phonon resummation method (SPR). The SPR method treats the adsorbed atom as a surface polaron where the phonon cloud accompanying the bound atom is a phonon coherent state. We conclude that, of the four approximations considered, only the SPR method gives a divergence-free result in the large membrane regime at finite temperature. The other three methods give an adsorption rate that diverges in the limit of an infinite surface.

Assessment of Complement Activation by Nanoparticles: Development of a SPR Based Method and Comparison with Current High Throughput Methods

A Surface Plasmon Resonance chip (SPR) was developed to study the activation of complement system triggered by nanomaterials in contact with human serum, which is an important concern today to warrant safety of nanomedicines. The developed chip was tested for its specificity in complex medium and its longevity of use. It was then employed to assess the release of complement fragments upon incubation of nanoparticles in serum. A comparison was made with other current methods assessing complement activation (μC-IE, ELISA). The SPR chip was found to give a consistent response for C3a release upon activation by nanoparticles. Results were similar to those obtained by μC-IE. However, ELISA detection of iC3b fragments showed an explained high non-specific background. The impact of sample preparation preceding the analysis was assessed with the newly develop SPR method. The removal of nanoparticles before analysis showed an important modification in the obtained response, possibly leading to false negative results. The SPR chip developed in this work allows for an automated assessment of complement activation triggered by nanoparticles with possibility of multiplexed analysis. The design of the chip proved to give consistent results of complement activation by nanoparticles.

Understanding Russell's viper venom factor V activator's substrate specificity by surface plasmon resonance and in-silico studies.

Blood coagulation factor V (FV) is activated either by Factor X or thrombin, cleaving at three different sites viz., Site I (Arg709-Ser710), site II (Arg1018-Thr1019), and site III (Arg1545-Ser1546). Russell’s viper venom factor V activator (RVV-V) is a thrombin-like serine proteinase that activates FV with selective, single cleavage at site III. A long lasting effort is being pending in understanding the ‘selective’ binding specificity of the RVV-V towards site III. Here, we present the binding kinetic study of RVV-V with two designed peptides corresponding to the regions from site I (Gln699—Asn713) and site II (1008Lys—Pro1022), respectively, that include 15 amino acids. Our investigation for justifying the binding efficacy and kinetics of peptides includes SPR method, protein-peptide docking, molecular dynamics simulation, and principal component analysis (PCA). Surprisingly, the SPR experiment disclosed that the Peptide II showed a lower binding affinity with KD of 2.775 mM while the Peptide I showed none. Docking and simulation of both the peptides with RVV-V engaged either rooted or shallow binding for Peptide II and Peptide I respectively. The peptide binding resulted in global conformational changes in the native fold of RVV-V, whereas the similar studies for thrombin failed to make major changes in the native fold. In support, the PCA analysis for RVV-V showed the dislocation of catalytic triad upon binding both the peptides. Hence, RVV-V, a serine protease, is incompetent in cleaving these two sites. This study suggests a transition in RVV-V from the native rigid to the distorted flexible structure and paves a way to design a new peptide substrate/inhibitor.

Abstract LB-068: From intracellular antibody fragments to small molecule inhibitors of mutant KRAS

Abstract Our aim was to develop methods to employ intracellular antibody fragments as lead macromolecules for small compound selections. We have used this approach to identify small molecules binding to mutant RAS with potential to inhibit the RAS-effector interactions. Mutation in RAS family members is among the most frequent in human cancer and the mutant RAS proteins are tumour-specific proteins for therapy. We have previously selected an intracellular antibody single domain fragment that binds to mutant forms of KRAS and HRAS and used this antibody fragment to demonstrate that blocking RAS-effector interaction-dependent signal transduction prevents tumour initiation and overt tumour growth in mouse preclinical models. The antibody fragment binds to GTP-bound RAS with high pM affinity and we have used this property to isolate compounds from a fragment library using a competitive SPR method that places the compounds in the region of the binding site of the antibody fragment. Using a combination of X-ray crystallography and medicinal chemistry, we have obtained a family of compounds that bind adjacent to the KRAS switch I region with nM affinity and that inhibit the downstream phosphorylation of AKT and ERK that results from RAS signaling. The chemical evolution and interaction characteristics of the KRAS-binding compounds will be described and their biochemical and cell-based properties presented. We have validated our approach using an antibody fragment as a screening tool for the identification of small molecule inhibitors of the RAS-effector interaction. This approach has yielded small compound fragments that are currently being developed as potential RAS-effector inhibitors in our medicinal chemistry programme. Citation Format: Camilo E. Quevedo, Abimael Cruz, Hanna Tulmin, Carole J. Bataille, Tomoyuki Tanaka, Donna Petch, Angela J. Russell, Simon Phillips, Terence H. Rabbitts. From intracellular antibody fragments to small molecule inhibitors of mutant KRAS [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-068. doi:10.1158/1538-7445.AM2017-LB-068

Estimating scatter from sparsely measured primary signal.

Scatter radiation severely degrades the image quality. Measurement-based scatter correction methods sample the scatter signal at sparsely distributed points, from which the scatter profile is estimated and deterministically removed from the projection image. The estimation of the scatter profile is generally done through a spline interpolation and the resulting scatter profile is quite smooth. Consequently, the noise is intact and the signal-to-noise ratio is reduced in the projection image after scatter correction, leading to image artifacts and increased noise in the reconstruction images. We propose a simple and effective method, referred to as filtered scatter-to-primary ratio ([Formula: see text]-SPR) estimation, to estimate the scatter profile using the sparsely sampled scatter signal. Using the primary sampling device and the stationary digital tomosynthesis systems previously developed in our lab, we evaluated and compared the [Formula: see text]-SPR method in comparison with existing methods in terms of contrast ratio, signal difference-to-noise ratio, and modulation transfer function. A significant improvement in image quality is observed in both the projection and the reconstruction images using the proposed method.

Exploring the binding mechanism and kinetics of Piperine with snake venom secretory Phospholipase A2

Secreted venom Phospholipase A2 is highly responsible for pharmacological effects like neurotoxicity, myotoxicity, hemolytic, anti-coagulation, and platelet aggregation. Neutralization of these pharmacological behaviors is one of the challenges existing for many decades and a potent drug compound for this is very much needed to control local effects of venom sPLA2. In this study, we investigated binding mechanism and kinetics of inhibition of Piperine (major constitute of Piper nigrum) with sPLA2 using DFT, MD simulation, MM-PBSA, and SPR method. Frontier MO properties were suggested that it procured better chemical reactivity and druglikeness and binding mode of Piperine with EcPLA2 defined that it occupied well in N-terminal hydrophobic cleft. The persistence of Piperine interactions with and without calcium ion was analyzed and confirmed by MD simulation analysis. The dPCA-based FEL shows the nature of apo- and Piperine-bound conformational behavior of EcPLA2 including intermediate forms. Further, binding energy of Piperine was calculated by high-throughput MM-PBSA which states that calcium ion presence enhances the Piperine binding by additional electrostatic interactions. Finally, kinetics of inhibition between Piperine and EcPLA2 implied that it secured better binding affinity (KD: as 1.708 pM) and the result gives clear evidence for the binding mechanism and binding energy calculated. In conclusion, Piperine was authenticated with better drug ability, entrenched binding interaction, and robust kinetics of inhibition with EcPLA2 through which it can become an exceeding drug candidate for pharmacological as well as catalytic activity of sPLA2.

Semantic Preference-Based Personalized Recommendation on Heterogeneous Information Network

In recent years, the Internet has become an indispensable part of people’s lives, and it offers increasingly comprehensive information tailored to people’s personal preferences as well as commodity attribute information. Consequently, many researchers have used external information to improve recommendation technology. However, most previous studies consider only adding single relationship types, such as social networking friend-relationships. In the real world, considering multiple types of external relations can more accurately determine the reason why a user selected an item. To address this problem, in this paper, we propose a hybrid method called the semantic preference-based personalized recommendation on heterogeneous information networks (SPR), which combines user feedback scores with heterogeneous information networks. This method can improve recommendation problems by considering multiple types of external relationships. To apply the method, we first introduce a similarity measure between users based on a user’s potential preferences in the meta-path and design the recommended model at the global and individual level. Finally, we perform experiments on two real-world data sets, finding that the SPR method achieves better results compared with the several widely employed and the state-of-the-art recommendation methods.

Поверхневий плазмонний резонанс: підходи і перспективи використання для дослідження вірус-специфічних взаємодій

In the review the published data on the use of surface plasmon resonance methods for the study of individual viral proteins as well as intact viruses are reviewed. . The principles of the method, its benefits and peculiarities of its use to study viruses are introduced. Particular attention is paid to the requirements to the sensor surface and the methods of its modification, including the formation self assembled monolayers of amphiphilic organic molecules containing functional groups to connect to the surface, creating of the intermediate protective thiocyanate layer between protein and metal, forming of the favorable microenvironment using dextran hydrogels around biomolecules, immobilization of proteins on the surface of the sensor using streptavidin-biotin system, use of protein A Staphylococcus aureus as an sensitive element of the sensory system structure. The approaches to enhance the signal used in virological studies, including the use of labeled antibodies, using competitive analysis for the detection of small molecules, the formation of a complex directly on the sensor surface, and immobilization on the surface of the sensor previously obtained complex receptor-analyte are considered. The conclusion is that the SPR method contains many potential opportunities to study various aspects of the interaction of viruses with specific agents, and changes in the structure of viruses caused by various external factors.

Amine coupling versus biotin capture for the assessment of sulfonamide as ligands of hCA isoforms

This work was dedicated to the development of a reliable SPR method allowing the simultaneous and quick determination of the affinity and selectivity of designed sulfonamide derivatives for hCAIX and hCAXII versus hCAII, in order to provide an efficient tool to discover drugs for anticancer therapy of solid tumors. We performed for the first time a comparison of two immobilization approaches of hCA isoforms. First one relies on the use of an amine coupling strategy, using a CM7 chip to obtain higher immobilization levels than with a CM5 chip and consequently the affinity with an higher precision (CV% < 10%). The second corresponds to a capture of proteins on a streptavidin chip, named CAP chip, after optimization of biotinylation conditions (amine versus carboxyl coupling, biotin to protein ratio). Thanks to the amine coupling approach, only hCAII and hCAXII isoforms were efficiently biotinylated to reach relevant immobilization (3000 RU and 2700 RU, respectively) to perform affinity studies. For hCAIX, despite a successful biotinylation, capture on the CAP chip was a failure. Finally, concordance between affinities obtained for the three derivatives to CAs isozymes on both chips has allowed to valid the approaches for a further screening of new derivatives.

Study of the sensor response of spun metal phthalocyanine films to volatile organic vapors using surface plasmon resonance

In this work, thin films of chloroaluminium phthalocyanine (ClAlPc), fluoroaluminium phthalocyanine (FAlPc) and fluorochromium phthalocyanine (FCrPc), which are insoluble in conventional solvents, were deposited by spin coating of their solutions in trifluoroacetic acid. The sensing response of these films versus acetic acid, three alcohols (methanol, ethanol, butanol) and three amines (methylamine, dimethylamine, trimethylamine) have been investigated using surface plasmon resonance as the sensing method. It has been shown that the sensor response of the investigated films decreases in the following order: acetic acid>alcohols>amines. The optical changes as monitored by SPR method have been used in conjunction with Fick's second law of diffusion to determine the diffusion coefficients of analyte vapor during the films’ swelling process. The obtained results showed that the diffusion coefficients and the swelling characteristics of the films are dependent on the functional group of the phthalocyanine molecule and the molecular size of the analyte.