Bovine Serum Albumin Matrix Research Articles

Nanocomposite conductive r(GO/BSA) hydrogel as an effective dressing for rapid chronic diabetic wound healing

Conductive hydrogels, with their soft, hydrated interface and superior electrical conductivity, represent a groundbreaking solution for diabetic wound healing. However, developing a conductive hydrogel with excellent biocompatibility has proven to be challenging. This study presents the synthesis of a novel conductive hydrogel composed of bovine serum albumin (BSA) protein and graphene oxide (GO) for the treatment of diabetic wounds. The prepared hydrogel is mildly reduced by ascorbic acid to facilitate charge-transfer and enhance its conductivity. Hydrogel is optimized for enhanced mechanical and electrical properties by changing the concentration of GO within the BSA matrix. The nanocomposite hydrogel demonstrates superior antibacterial properties and enhanced biocompatibility compared to the BSA hydrogel. The prepared hydrogel is investigated for wound healing capacity in a rat model, where it demonstrates rapid healing of chronic diabetic wound. The improved therapeutic outcomes are attributed to the hydrogel's ability to facilitate cellular activities through enhanced electrical conductivity by maintaining continuous electrical signal at the wound site. The presented findings suggest that nanocomposite protein-based conductive hydrogel not only hold great potential for advanced diabetic wound care and have potential for future innovation in tissue engineering, regenerative medicine and beyond.

Universal nanocomposite coating with antifouling and redox capabilities for electrochemical affinity biosensing in complex biological fluids.

Electrochemical affinity biosensors have the potential to facilitate the development of multiplexed point-of-care diagnostics in complex biological fluids. However, their commercial viability has been hindered by challenges such as electrode biofouling and the lack of inherent redox properties. To address this unmet need, we have developed a universal nanocomposite coating which is unique in its ability to not only allow oriented conjugation of the biorecognition element but also specific detection directly in complex biological fluids like serum and urine owing to its built-in antifouling and redox capabilities, thus improving suitability for point of care testing. This multifunctional coating comprises a 3D porous crosslinked bovine serum albumin matrix for oriented conjugation and antifouling properties with embedded graphene nanosheets modified with amino-ferrocene for enhanced conductivity and mediator-free biosensing. The coating showed minimal signal degradation despite prolonged exposure to 1% bovine serum albumin, artificial urine and untreated human serum for up to 30 days. To demonstrate its utility, we fabricated and tested proof-of-concept electrochemical immunosensors for bladder cancer protein biomarkers, specifically interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF). The practical feasibility was highlighted by the excellent sensitivity and specificity observed for IL-8 and VEGF with a limit of detection of 41 pg mL-1 and 67 pg mL-1, respectively. Consequently, this universal nanocomposite-based electrochemical biosensing platform can be extended to the point of care testing of a broad spectrum of biomarkers present in complex biological fluids, thus enabling reliable and early diagnostics.

(Invited) F-ALDH, a New Catalyst for Enzyme and Aptamer- Based Electrochemical Biosensors

The selectivity, affinity and catalytic activity are key characteristics which recommend enzymes as components of biosensors, whether for use as main recognition element or for signal amplification. Additionally, the enzyme inhibition by various molecules can be exploited for analytical purposes. In the search for new enzymes with good stability and catalytic properties, a recombinant psychrophilic aldehyde dehydrogenase from the Antarctic Flavobacterium PL002 was recently characterized and shown to have potential in biosensing [1-5].The enzyme is active in a wide temperature range up to 60º C and has high catalytic activity [1,2]. It accepts various aldehydes substrates with Michaelis Menten constants of e.g., Km = 0. 137 ± 0.016 mmol L−1 for benzaldehyde. The enzyme may use both nicotinamide adenin dinucleotide (NAD+) and nicotinamide adenin dinucleotide phosphate (NADP+) as cofactors and has higher affinity for NAD+ ( Km=0.033mmol L−1 and 0.431 mmol L−1 for NAD+ and NADP+, respectively [2]). As for other aldehyde dehydrogenases, the enzyme is inhibited by heavy metals and dithiocarbamate fungicides [2,3].To explore its potential as recognition element in biosensors, enzymatic tests and electrochemical biosensors exploiting the catalytic activity of F-ALDH or its inhibition were first developed [4,5]. In biosensors, the enzyme was immobilized by cross linking in a matrix of bovine serum albumin [5] or by nickel-histidine affinity. Enzymatic inks with a stability of several months at 4º C were obtained by immobilizing the enzyme on magnetic particles functionalized with a complex of nickel-nitrilotriacetic acid (Ni-NTA) followed by mixing with different additives. Practical applications for the specific detection of (i) benzaldehyde in a pharmaceutical ingredient [5] and (ii) acetaldehyde in wines were demonstrated. In wines, acetaldehyde is present in a free form or bound to sulphur dioxide or phenolic compounds. Both free and bound acetaldehyde are relevant for wine quality and its evolution. The F-ALDH enzyme enables testing of both forms in cellar like conditions. Moreover, the detection of free acetaldehyde serves as example for aldehydes detection in vapor phase, opening the way for other similar applications.A separate line of research explored the potential of F-ALDH for the quantitative determination of enzyme’s inhibitors. Spectrophotometry measurements emphasized a 15% reduction of enzyme’s activity in the presence of either 28 ppb thiram or 0.5 ppb mercury chloride. The solution advanced for overcoming the selectivity issues in the detection of thiram is to couple the electrochemical biosensor measuring the F-ALDH inhibition with SERS measurements of the dithiocarbamate fungicide [6].Finally, the F-ALDH enzyme may serve as label in electrochemical aptasensors. The enzyme was attached to an aptamer for lysozyme via Ni-histidine affinity and preserved good catalytic activity for the conversion of acetaldehyde. Preliminary studies were focused on investigating the affinity of the enzyme-labeled aptamer for lysozyme in relation to the linker length.Based on the demonstrated catalytic activity of the enzyme and its preservation upon immobilization on different supports or by linking to an aptamer, various sensing configurations can be envisaged that will exploit the potential of the new enzyme. Acknowledgements: This work was financially supported by the UEFISCDI projects ERANET-M-ENZ4IFACES, contract 166/01.05.2020 (for AV, GNP and CP) and PN-III-P4-ID-PCE-2020-2297 E-MAP, contract 84/9.02.2021 (for RMB and AF). References Necula-Petrareanu G, Lavin P, Vasilescu A, Purcarea C (2018) Antarctic Flavobacterium aldehyde dehydrogenase – a cold adapted catalyst for biosensing. J Biotechnol 280:S18. https://doi. org/10.1016/j.jbiotec.2018.06.054Necula-Petrareanu, G.; Lavin, P.; Paun, V.I.; Gheorghita, G.R.; Vasilescu, A.; Purcarea, C. Highly stable cold-active aldehyde dehydrogenase from the marine Antarctic Flavobacterium sp. PL002. Fermentation. 2022 8(1):7-24 https:// doi.org/10.3390/fermentation8010007Vasilescu A, Titoiu A.M, Purcarea C, Necula Petrareanu G, Method for determining thiram fungicide based on enzymatic inhibition and electrochemical sensor, Romanian patent application, OSIM RO133890A2 /13.08.2018Titoiu AM, Lapauw M, Necula-Petrareanu G, Purcarea C, FanjulBolado P, Marty J-L, Vasilescu A (2018) Carbon nanofiber and Meldola Blue based electrochemical sensor for NADH: application to the detection of benzaldehyde. Electroanalysis 30(11):2676– 2688. https://doi.org/10.1002/elan.201800472Titoiu, A. M., Necula-Petrareanu, G., Visinescu, D., Dinca, V., Bonciu, A., Mihailescu, C. N., ... Vasilescu, A. (2020). Flow injection enzymatic biosensor for aldehydes based on a Meldola Blue-Ni complex electrochemical mediator. Microchimica Acta, 187(10).doi:10.1007/s00604-020-04477-3Ibáñez D, González-García MB, Hernández-Santos D, Fanjul-Bolado P. Detection of dithiocarbamate, chloronicotinyl and organophosphate pesticides by electrochemical activation of SERS features of screen-printed electrodes. Spectrochim Acta A Mol Biomol Spectrosc. 2021 Mar 5;248:119174. doi: 10.1016/j.saa.2020.119174

Electrochemical immunosensor utilizing a multifunctional 3D nanocomposite coating with antifouling capability for urinary bladder cancer diagnosis

Currently available point-of-care tests for Bladder Cancer (BC) are qualitative and prone to high false positives, thus preventing them from replacing clinical cystoscopy as reliable stand-alone diagnostics. In this study, we have targeted this unmet need by developing a label-free electrochemical impedimetric immunosensor for detection of APO-A1, a major high-density lipoprotein that is overexpressed in the urine of early-stage bladder cancer patients. The immunosensor utilizes a novel multifunctional 3D nanocomposite coating consisting of a porous bovine serum albumin (BSA) matrix embedded with a network of highly conductive and biocompatible gold coated silver nanowires (Au@AgNWs). The main components of this nanocomposite coating and their specific functions include: (i) A 3D porous BSA matrix to enable oriented antibody conjugation and prevent non-specific protein adsorption while allowing diffusion of analyte with minimal hindrance as compared to traditional antifouling coatings (ii) Embedded Au@AgNWs that enhance biocompatibility and improve charge transfer to the underlying electrode. The nanocomposite coating demonstrated minimal decrease in electrochemical performance even after 1-month of incubation in 1% BSA, human serum and human urine. Furthermore, the low-cost and disposable screen-printed electrochemical immunosensor exhibited excellent feasibility for sensitive and specific APO-A1 detection in the clinically relevant sensing range of 100 pg/mL to 250 ng/mL with high reproducibility (n = 5, RSD=2.2%) and an impressive LOD of 22 pg/mL. These results highlight the potential of the proposed immunosensor to enable reliable early diagnosis of bladder cancer at the point-of-care and serve as a viable alternative to cystoscopy.

In vitro corrosion and in vivo behavior of high strength Mg-6Zn-1Mn alloy wire for gastrointestinal anastomosis nail application

Ti and its alloy staples can be retained in the human body for a long period because of their excellent corrosion resistance and thus requires revision surgery for removal. In this study, biodegradable Mg-6Zn-1Mn alloy staples were fabricated using ∼99.8 % area reduction cold drawing, whose service performance was evaluated by in vitro corrosion and in vivo tests. The high strength (∼340 MPa) of staples is mainly attributed to the formation of fine grains, nanoparticles, and additional dislocations. Moreover, owing to the effect of fine grains, as well as the high Schmid factor of prismatic ⟨a⟩ slip and pyramidal ⟨c+a⟩ slip, the staples also exhibit acceptable ductility (∼10 %). The in vitro corrosion results indicate that staple fractures occurred after immersion for 21 h in a single PBS solution. With the addition of ∼0.5 g/L bovine serum albumin (BSA), the time required to maintain the mechanical integrity of staples can expand to 90 h. This is mainly related to the adsorption and chelating effects between BSA and Mg matrix. After the implantation surgery, all rabbits fully recovered with normal oral intake, and Mg ions generated by degradation effectively promoted the absorption of the alimentary system. Therefore, the Mg-6Zn-1Mn alloy staples fabricated in this study exhibit desired effect, and excellent clinical application prospects.

Ecotoxicity and interacting mechanism of anionic surfactant sodium dodecyl sulfate (SDS) and its mixtures with nonionic surfactant fatty alcohol-polyoxyethlene ether (AEO)

This paper reports the proportion-dependent toxicity of binary surfactant mixtures containing anionic sodium dodecyl sulfate (SDS) and nonionic fatty alcohol-polyoxyethlene ether (AEO) toward Photobacterium phosphoreum. The crucial role of toxicity interactions was elucidated by spectroscopic probing the refolding of the unfolded bovine serum albumin (BSA) induced by SDS and theoretical calculating the interaction parameter of mixed surfactants based on Rubingh’s model from the critical micelle concentrations. The SDS/AEO mixtures can be divided into two groups based on the toxicity response to the proportion of AEO in the mixtures: Group I contained low mass proportions of AEO, that is, SDS:AEO = 4:1, 3:1; Group II featured high AEO proportions, that is, SDS:AEO = 3:2, 1:1, 2:3, 1:4. The toxicity of SDS/AEO mixtures decreased with the enhanced proportion of AEO in Group I and then fluctuated slightly when the AEO proportion increased to that of Group II. The mixture with the mass ratio of 1:1 showed a slightly higher toxicity than the others in Group II. Scanning electron microscopy (SEM) images illustrated that the addition of AEO hindered the action of SDS against the cell membrane. Fluorescence measurement indicated that AEO could extract SDS molecules embedded in the BSA matrix, except for those bound to the highly active sites of BSA, and refold stepwise the unfolded protein. The results were in excellent analogy to the proportion-dependent toxicity of SDS/AEO mixture, indicating the formation of mixed micelles playing a key role. The interaction parameter further revealed that antagonism led to the mixture with equal mass ratio (1:1) showing higher toxicity than other mass ratios in Group II. These results can be useful for compounding SDS/AEO mixtures in application efficiently and eco-friendly.

Red-emitting BSA-stabilized copper nanoclusters acted as a sensitive probe for fluorescence sensing and visual imaging detection of rutin

In this article, red-emitting copper nanoclusters (Cu NCs) were prepared in the matrix of bovine serum albumin (BSA) through using N2H4·H2O as a reducing agent and BSA as a stabilizer. In the aqueous suspension of BSA-Cu NCs, the addition of rutin enabled the combination of rutin with BSA around Cu NCs via hydrogen bond and electrostatic interactions between functional groups of BSA and rutin. The approaching of rutin to Cu NCs induced that the fluorescence (FL) of Cu NCs was quenched by rutin due to the electron transfer from Cu NCs to rutin. Under the optimal conditions, the FL of Cu NCs was linearly decreased with the increase of rutin concentration from 0.1 to100 μM, together with a low detection limit of ca. 0.02μM. The FL quenching responses of Cu NCs were highly selective and sensitive towards rutin, over potential interferents in real human serum samples. Based on BSA-Cu NCs, this as-proposed FL probe exhibited a superior capability of rutin detection in real human serum samples. Significantly, this probe of rutin could realize the FL sensing of rutin and the naked-eye visual FL imaging detection of rutin in aqueous solution and on filter paper.

Spectral Studies of Biodegradation and Hemolysis Caused by Contact of Bulk and Film Nanocomposites with Biological Fluids

The paper discusses the possibility of use of nanocomposites obtained by laser structuring of single-walled (SWCNTs) and multi-walled (MWCNTs) carbon nanotubes in bovine serum albumin matrix as tissue-engineering scaffolds for blood vessel network sprouting in the process of biodegradation of the nanocomposite implant. The lowest rate of biodegradation was obtained in bulk and film nanocomposites based on SWCNTs immersed in NaCl solution: 2.45 and 9.77% weight loss after 14 days, respectively. Analysis of the dynamics of changes in the optical density of NaCl solution showed intense biodegradation of nanocomposites after six days of immersion. Spectral studies showed that contact of blood with bulk and film nanocomposites based on SWCNTs did not lead to hemolysis (hemolysis level ≤ 0.5%).

Facile synthesis of bovine serum albumin conjugated low-dimensional ZnS nanocrystals

We present a facile synthesis of bovine serum albumin (BSA) conjugated low-dimensional ZnS nanocrystals. The experimental parameters such as effects of BSA concentration and precursor vol ratios of Zn:S on the formation of ZnS nanoparticles in BSA matrix were investigated. The ZnS crystalline sizes of 1.9, 1.8 and 1.6nm were obtained by using the BSA concentrations of 1×10−4, 5×10−4 and 10×10−4g/mL, respectively, with a fixed Zn:S vol ratio of 1:1. The ZnS samples prepared from 1:10 and 10:1 vol ratios of Zn:S at BSA concentration of 5×10−4g/mL shows the crystalline sizes of ZnS are 2.1 and 1.5nm, respectively. FT−IR analysis suggests that the prepared ZnS nanoparticles might be conjugated through the interactions of hydroxyl and amine groups present in BSA. We evaluate the cytotoxicity of the prepared ZnS nanoparticles, the THP-1 cells showed a good viability (>88%) for all the prepared ZnS samples. The plausible mechanism for the formation of ZnS-BSA composite has also been discussed.

Development of a validated strategy for the determination of tryptamine in human cerebrospinal fluid in the presence of competitors using molecularly imprinted polymers.

This study presents a validated strategy for the determination of tryptamine in the presence of its competitors, which involves the molecularly imprinted solid-phase extraction combined with high-performance liquid chromatography coupled with fluorimetric detection. Tryptamine-imprinted microscale sorbent was produced from 4-vinylbenzoic acid and ethylene glycol dimethacrylate in methanol by precipitation polymerization, and its imprinting factor was equal to 15.4 in static experiments or 18.6 in dynamic binding experiments. The method for tryptamine determination in the presence of serotonin and l-tryptophan was validated using a complex matrix of bovine serum albumin yielding the recoveries of tryptamine that ranged between 98.7 and 107.0%. Very low limits of detection and limits of quantification for tryptamine (19.9 and 60.3nmol/L, respectively) allow the quantification of tryptamine in human cerebrospinal fluid in the presence of tryptophan and serotonin.

Study of the structure of 3-D composites based on carbon nanotubes in bovine serum albumin matrix by X-ray microtomography

3-D composites are widely used in tissue engineering. A comprehensive analysis by X-ray microtomography was conducted to study the structure of the 3-D composites. Comprehensive analysis of the structure of the 3-D composites consisted of scanning, image reconstruction of shadow projections, two-dimensional and three-dimensional visualization of the reconstructed images and quantitative analysis of the samples. Experimental samples of composites were formed by laser vaporization of the aqueous dispersion BSA and single-walled (SWCNTs) and multi-layer (MWCNTs) carbon nanotubes. The samples have a homogeneous structure over the entire volume, the percentage of porosity of 3-D composites based on SWCNTs and MWCNTs - 16.44%, 28.31%, respectively. An average pore diameter of 3-D composites based on SWCNTs and MWCNTs - 45 μm 93 μm. 3-D composites based on carbon nanotubes in bovine serum albumin matrix can be used in tissue engineering of bone and cartilage, providing cell proliferation and blood vessel sprouting.

Use of Indocyanine Green in Nanocomposite Solders to Increase Strength and Homogeneity in Laser Welding of Tendons

The ability to form sutures in bovine tendon using a prototype laser biological tissue welding device was demonstrated. New solder compositions are proposed, based on carbon nanotubules (0.1% w/w) in an aqueous matrix of bovine serum albumin (25% w/w) supplemented with the medical laser dye indocyanine green (0.01% w/w). The absorption peak of the nanocomposition solder coincided with the apparatus wavelength of 800 nm. The use of indocyanine green as radiation absorber in nanocomposition solders provided increases in the strength of laser weld sutures in tendons. The maximum level of ~0.82 MPa was achieved using a solder based on multiwalled carbon nanotubules. X-Ray microtomography demonstrated uniformity in the joining of tendons in depth and length during formation of nanocomposite between the two welded biological tissue fragments. Growth of fibroblast cells on the composite surface formed at the site of the laser weld suture was demonstrated.

Self-Assembled Fluorescent Bovine Serum Albumin Nanoprobes for Ratiometric pH Measurement inside Living Cells.

In this work, we demonstrated a new ratiometric method for the quantitative analysis of pH inside living cells. The structure of the nanosensor comprises a biofriendly fluorescent bovine serum albumin (BSA) matrix, acting as a pH probe, and pH-insensitive reference dye Alexa 594 enabling ratiometric quantitative pH measurement. The fluorescent BSA matrix was synthesized by cross-linking of the denatured BSA proteins in ethanol with glutaraldehyde. The size of the as-synthesized BSA nanoparticles can be readily manipulated from 30 to 90 nm, which exhibit decent fluorescence at the peak wavelength of 535 nm with a pH response range of 6-8. The potential of this pH sensor for intracellular pH monitoring was demonstrated inside living HeLa cells, whereby a significant change in fluorescence ratio was observed when the pH of the cell was switched from normal to acidic with anticancer drug treatment. The fast response of the nanosensor makes it a very powerful tool in monitoring the processes occurring within the cytosol.

Ultrasound-induced albumin gelation method for the preparation of nanostructured hydroxyapatite

An ultrasound-induced albumin gelation method was utilized to prepare nanostructured hydroxyapatite (HAP). After ultrasound irradiation, hybrid colloids of bovine serum albumin (BSA) and amorphous calcium phosphate (ACaP) were formed, where the nanosized ACaP was homogenously distributed in the fibril-like BSA matrix. The freeze-dried BSA/ACaP sponge showed an oriented pore structure and the ACaP nanoparticles were transformed into nanostructured HAP after calcinations at 400–600°C. With the aid of BSA/ACaP sponge, HAP nanocrystals were aggregated into rod-like nanostructures, which were merged into large rod-like HAP crystals at 700°C. This study demonstrates that ultrasound-induced albumin gelation method can be successfully used to fabricate nanostructured HAP.

Novel Desaturation Cell to Quantify Gushing Intensity: A Preliminary Study on Model Solutions

Beer gushing is an unwanted phenomenon that occurs when the beer foam spontaneously gushes out when a bottle or can is opened. Despite long-term research, gushing still has not been fully explained. To our knowledge, there is no simple, quick, and inexpensive method for reliably measuring gushing intensity. In this article, a desaturation cell enabling saturation, step-wise pressure drop, and image analysis of foam formation is presented. The gushing intensity was evaluated through foam formation rate and relative final foam volume. To study the physicochemical mechanism of gushing, the measurements were carried out in a simple gushing matrix made of water and bovine serum albumin (BSA), the aggregates or micelles of which serve as nucleation sites for bubble formation. The effect of hop bitter compounds (iso-α-acids and tetrahydro-iso-α-acids) and essential oils (linalool) in the BSA matrix was also tested. The hop bitter compounds increased the foam formation rate significantly while affecting the foam volume less. Linalool at low concentration caused an extremely high foam formation rate whereas, at higher concentration, did not affect the foaming of the BSA matrix.

Facile synthesis of β-lactoglobulin-functionalized multi-wall carbon nanotubes and gold nanoparticles on glassy carbon electrode for electrochemical sensing

A facile approach was developed for the preparation of nanocomposite based on β-lactoglobulin (BLG)-functionalized multi-wall carbon nanotubes (MWCNTs) and gold nanoparticles (GNPs) for the first time. Owing to the amphipathic nature, BLG can be adopted onto the surface of MWCNTs to form BLG-MWCNTs with uniform dispersion in water. Taking advantage of sulfhydryl groups on BLG-MWCNTs, GNPs were decorated on the BLG-MWCNTs-modified glassy carbon electrode (GCE) by electrodeposition. The nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy and X-ray spectroscopy analysis. Cyclic voltammetry and chronoamperometric method were used to evaluate the electrocatalytic ability of the nanocomposite. Furthermore, a glucose biosensor was developed based on the immobilization of glucose oxidase with cross-linking in the matrix of bovine serum albumin (BSA) on the nanocomposite modified GCE. The resulting biosensor exhibited high sensitivity (3.98μAmM−1), wider linear range (0.025–5.5mM), low detection limit (1.1μM at the signal-to-noise ratio of 3) and fast response time (within 7s) for glucose detection.

A separation of tyramine on a 2-(4-methoxyphenyl)ethylamine imprinted polymer: An answer from theoretical and experimental studies

A 2-(4-methoxyphenyl)ethylamine imprinted polymer (MIP) was successfully applied for the selective separation of tyramine. A computational analysis was used to predict the affinity of the polymer matrix towards tyramine and a preliminary experimental evaluation was made for the target analyte. Then the experimental analysis of polymer towards tyramine was continued. The binding sites were characterized with employment of the Langmuir and Freudlich models. After the optimization of solid phase extraction towards tyramine, the most appropriate systems for the extraction steps were chosen: methanol–water 85:15 v/v for the loading and the washing as well as 0.04M aq. ammonium acetate–methanol 30:70 v/v for the elution steps. The biogenic compounds as tryptamine, serotonin, octopamine, synephrine, and l-tyrosine were used for the selectivity study on the basis of binding capacities of the analytes on the imprinted and the non-imprinted polymers. The theoretical approach to obtained results allowed to explain the adsorption selectivity of the tested polymer. Finally, the complex matrix of bovine serum albumin was used to show the usefulness of imprinted material for bioanalysis. The obtained recoveries showed the superiority of MIP over the commercial sorbent C18. Total recoveries of tyramine from spiked bovine serum albumin sample were determined as: 95±2%, 14±3%, and 1.9±0.4% for the imprinted, non-imprinted, and commercial C18 sorbents, respectively.

A Glassy Carbon Electrode Modified with Glucose Oxidase and MWCNT‐Palladium Nanoparticles for the Determination of Glucose

AbstractA glucose biosensor based on glucose oxidase (GOx) with cross‐linking in a matrix of bovine serum albumin (BSA) and MWCNTs‐palladium nanoparticles was developed and characterized. Nafion/GOx/MWCNTs‐Pd/GCE was simply and quickly prepared; it showed improved sensitivity of glucose determination. Amperometric testing demonstrated the sensor’s fast responses with linear regression observed even at very low concentrations below 1.0 mM. Linear responses to glucose were observed between 1.0 µM and 10 mM at an applied potential of 0.4 V. The sensor demonstrated fast responses and good stability.

Disposable biosensor based on immobilisation of glutamate oxidase on Pt nanoparticles modified Au nanowire array electrode

Novel electrochemical platform based on Pt nanoparticle modified ordered three-dimensional gold nanowire arrays (PtNP/NAEs) for the amperometric sensing of H 2O 2 and glutamate is developed. Pt nanoparticle (PtNP) is fabricated by electrodeposition onto the 3D nanowires and characterised using scanning electron microscopy (SEM) and cyclic voltammetry. The deposited nanoparticles have an average size of 20 nm. The PtNP/NAE shows a linear response of up to 20 mM for H 2O 2 detection with a sensitivity of 194.60 μA mM −1 cm −2 at 20 °C. It can detect 1 μM (S/N = 3) of H 2O 2 at normal condition without using any enzyme or mediator. Analytical performance of this electrode is tested by immobilising glutamate oxidase (GlutOx) through cross-linking in the matrix of bovine serum albumin (BSA), Nafion and glutaraldehyde. At physiological pH, the biosensor showed the sensitivity of 10.76 μA mM −1 cm −2, with a linear range of up to 0.8 mM.

Oral delivery of low molecular weight heparin microspheres prepared using biodegradable polymer matrix system

Parenteral route is preferred for low molecular weight heparin (LMWH) due to poor oral bioavailability. Biodegradable formulation components were evaluated for possible interactions between the physical mixtures using differential scanning calorimetry. LMWH and an absorption enhancer papain were encapsulated in bovine serum albumin matrix and four formulations were spray-dried (MS.1, MS.2, MS.3, MS.4). Formulations were evaluated for product yield, particle size, particle charge and encapsulation efficiency. In vitro release assessed in pH 7.2 phosphate buffer saline (PBS) revealed a burst release effect (60%) for all the formulations except MS.1. In vivo studies performed in male Sprague Dawley rats showed an enhancement in drug absorption for the MS.2 and MS.3 formulations because of papain action on paracellular tight junctions. A significant increase in LMWH oral bioavailability was demonstrated by MS.3 (21%), among the formulations encapsulated with papain.