Santanu Ray - Academia.edu (original) (raw)

Papers by Santanu Ray

Full LA-ICPMS dataset for the extended element list analyses. Salinities determined from microthe... more Full LA-ICPMS dataset for the extended element list analyses. Salinities determined from microthermometric analyses and used to calculate chlorinity. Concentrations reconstructed using the method of Allan <i>et al</i>. (2005).

Full LA-ICPMS data set for the Au specific element list analyses. Salinities determined from micr... more Full LA-ICPMS data set for the Au specific element list analyses. Salinities determined from microthermometric analyses and used to calculate chlorinity. Concentrations reconstructed using the method of Allan <i>et al</i>. (2005).

npj Materials Degradation, 2019

Accelerated low water corrosion is a form of marine steel corrosion caused by bacterial activity.... more Accelerated low water corrosion is a form of marine steel corrosion caused by bacterial activity. It has a global spread and is potentially responsible for billions of pounds of damage. We have determined in detail both the chemistry of corrosion products and the associated microbiology at a UK site. The corrosion products form a layered structure with iron sulfides at the steel surface and iron oxides and sulfates in contact with water. The iron sulfides are formed by reaction of steel with hydrogen sulfide formed by sulfate-reducing bacteria and are oxidised through a series of sulfur oxidation states by sulfide-oxidising bacteria, forming acid at all stages and encompassing the whole of the bacterial sulfur cycle. The bacteria involved are endemic in anoxic bed sediment, and the process is a response to the presence of steel as an electron donor, and the generation of anoxic microenvironments within corrosion products.

Colloids and Interfaces, 2019

Nitric oxide (NO) generating surfaces are potentially promising for improving haemocompatibility ... more Nitric oxide (NO) generating surfaces are potentially promising for improving haemocompatibility of blood-contacting biomaterials. In the present report, Cu-modified poly(vinyl chloride) (PVC) and polyurethane (PU) were prepared via polydopamine (pDA)-assisted chelation. The copper content on the PVC and PU modified surfaces, assessed by inductively coupled plasma - optical emission spectrometry (ICP-OES), were about 3.86 and 6.04 nmol·cm−2, respectively. The Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) data suggest that copper is attached to the polymer surface through complex formation with pDA. The cumulative leaching of copper from modified PVC and PU during the five day incubation in phosphate buffered saline (PBS), measured by inductively coupled plasma mass spectrometry (ICP-MS), was about 50.7 ppb and 48 ppb, respectively which is within its physiological level. Modified polymers were tested for their ability to catalytically gene...

Colloids and Surfaces A: Physicochemical and Engineering Aspects

Polyoxometalates (POMs) are the oxyanion clusters of early transition metals (mostly molybdenum (... more Polyoxometalates (POMs) are the oxyanion clusters of early transition metals (mostly molybdenum (VI), tungsten (VI) and vanadium (V)) and they show interesting properties particularly in the field of catalysis and sensing chemistry. In this work molybdenum blue (MB), phosphomolybdenum blue (PMB) and arsenomolybdenum blue (AsMB) are prepared using glutathione (GSH) as reducing agent in acid-free condition. The MB species are further characterised by UV-vis spectroscopy, Raman spectroscopy, XPS, powder XRD and FTIR spectroscopy. The prepared MB solutions showed an exciting behaviour in Aqueous Biphasic Systems (ABS) using PEG#4000 and Na 2 SO 4 as phase forming components. MB and PMB partition to the micellar medium of PEG upto 44 % and 66 % respectively but AsMB is not at all partitioned. Therefore the method is useful for differentiating PMB and AsMB. PEG has been recovered using ultra-filtration technique after the ABS. The experiment also reveals that GSH, a biomolecule with high physiological impact, can be detected at trace concentrations by PMB formation method both in water and blood serum media.

The adsorption of bovine serum albumin (BSA), immunoglobulin G (IgG) and fibrinogen (Fgn) on fluo... more The adsorption of bovine serum albumin (BSA), immunoglobulin G (IgG) and fibrinogen (Fgn) on fluorinated selfassembled monolayers have been studied using time of flight secondary ion mass spectrometry (ToF-SIMS) and Spectroscopic Ellipsometry (SE). The objective of the work has to establish the utility of ToF-SIMS for the determination of the amount of protein adsorbed on the surface. Quantification of surface adsorbed proteins was carried out using SE and a good correlation between ToF-SIMS results and SE was achieved. The surface distribution of proteins were also analysed using Atomic Force Microscopy (AFM). We show that the surface distribution of proteins strongly affect the ToFSIMS results.

Applied Surface Science, 2020

Non-aqueous electrolyte containing aluminium chloride (AlCl3) and 1-ethyl-3methylimidazolium chlo... more Non-aqueous electrolyte containing aluminium chloride (AlCl3) and 1-ethyl-3methylimidazolium chloride ([EMIm]Cl) topped with n-decane was used to electrodeposit aluminium (Al) coating via chronoamperometric method at ambient atmosphere. Aluminiumgraphene oxide (Al-GO) composite coating was further obtained from the Al electrolytic bath by dispersing GO in it. GO was prepared by oxidation of high purity graphite. The Al deposition potential was noted by cyclic voltammetry (CV) method. Influence of GO on the morphology and microstructure of Al metal matrix was analysed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction spectroscopy (XRD). Inclusion of GO into the Al matrix enhanced the coating compactness thus nullifying the surface defects which were observed for the pristine Al deposit. The texture coefficient calculation showed that the addition of GO altered the growth texture from growth predominately along (002) plane for pure Al coating to growth predominantly along (111) and (022) plane for Al-GO composite coating. The morphological and microstructural changes occurred in the Al coating from GO incorporation influenced the anti-corrosion behaviour of the coatings. The electrochemical corrosion analysis by Tafel polarization and Impedance 2 Spectroscopy confirmed that the GO reinforced Al deposit possessed twofold enhanced anticorrosive property than pure Al coating.

Diamond and Related Materials, 2020

Graphene reinforced, Zn-rich, Zinc-Nickel-Iron (ZnNiFe-G) coatings were deposited on mild steel s... more Graphene reinforced, Zn-rich, Zinc-Nickel-Iron (ZnNiFe-G) coatings were deposited on mild steel substrate by electrolyzing the Zn-Ni-Fe acidic sulphate bath containing different amounts of dispersed graphene layers. Effect of graphene incorporation on composition, microstructure, morphology and electrochemical corrosion performance of coatings was investigated. X-ray diffraction studies revealed ZnNiFe coatings consists η Zn, γ Ni2Zn11 and Fe phases but the concentration of γ Ni2Zn11 phase increased with increasing graphene content in the coating.

Materials Chemistry and Physics, 2020

The article reports on the generation of Ru-morin nanocomposites using a simple methodology in pr... more The article reports on the generation of Ru-morin nanocomposites using a simple methodology in presence and in absence of γ-irradiation. The nanocomposites were characterized using several techniques including, N 2 adsorption-desorption, Brunauer−Emmett−Teller (BET) method, transmission electron microscopy (TEM), Fourier transform infra-red (FTIR) spectroscopy, powder X-ray diffractometric (XRD) technique, dynamic light scattering (DLS) and X-ray photoelectron spectroscopic (XPS) methods. The results revealed the production of comparatively smaller sized particles with smaller pores when prepared in presence of energetic γ-irradiation. The irradiated nanocomposite was found to be an eligible candidate for analytical sensing of Ce(IV), Ce(III) and Dy(III) out of a set of different lanthanoids. The lowest values of limit of detection (LOD) out of all the pH conditions for Ce(IV), Ce(III) and Dy(III) were 0.09 μM (at pH 12), 0.08 μM (at pH 12) and 5.37 µM (at pH 2) respectively using absorption spectroscopy. The LOD of Ce(IV) at pH 7 was found to be 0.35 μM by fluorescence spectroscopic method. It is established that the sensing is a pH dependent phenomenon which enables a selective and mutually exclusive sensing of these three lanthanoids individually. The study was also extended towards two environmental samples viz., tap water and ground water with significant recovery of Ce(IV), Ce(III) and Dy(III) from tap water and Ce(IV) and Dy(III) from ground water.

ACS Omega, 2019

A mild and sustainable synthetic route was followed for the generation of biomolecule-assisted Ru... more A mild and sustainable synthetic route was followed for the generation of biomolecule-assisted Ru nanocatalyst under open as well as inert atmosphere using the polyphenol morin. The nanocatalyst was characterized thoroughly by powder X-ray diffraction, N 2 adsorption− desorption, high-resolution transmission electron microscopy, dynamic light scattering, X-ray photoelectron spectroscopy, absorption spectroscopy, Fourier transform infrared spectroscopy, fluorescence spectroscopy, thermogravimetric analysis, and inductively coupled plasma optical emission spectrometry. The nanocatalyst reveals excellent catalytic activity for the reduction of several substituted nitrobenzene to aniline derivatives under simple, mild, and environment-friendly conditions. The catalyst can be reused for four consecutive cycles without significant loss in its catalytic activity.

RSC Advances, 2018

Agricultural production results in wastes that can be re-used to improve the quality of the envir... more Agricultural production results in wastes that can be re-used to improve the quality of the environment.

Nature communications, Dec 22, 2017

The spread of bacterial resistance to antibiotics poses the need for antimicrobial discovery. Wit... more The spread of bacterial resistance to antibiotics poses the need for antimicrobial discovery. With traditional search paradigms being exhausted, approaches that are altogether different from antibiotics may offer promising and creative solutions. Here, we introduce a de novo peptide topology that-by emulating the virus architecture-assembles into discrete antimicrobial capsids. Using the combination of high-resolution and real-time imaging, we demonstrate that these artificial capsids assemble as 20-nm hollow shells that attack bacterial membranes and upon landing on phospholipid bilayers instantaneously (seconds) convert into rapidly expanding pores causing membrane lysis (minutes). The designed capsids show broad antimicrobial activities, thus executing one primary function-they destroy bacteria on contact.

Org. Biomol. Chem., 2017

Silica-specific motifs templated into fibre-forming peptides effectively silicify protein fibres.

Angewandte Chemie (International ed. in English), Jan 29, 2017

Binary encoding of peptide sequences into differential antimicrobial mechanisms is reported. Such... more Binary encoding of peptide sequences into differential antimicrobial mechanisms is reported. Such sequences are random in composition, but controllable in chain length, are assembled from the same two amino acids, but differ in the stereochemistry of one. Regardless of chirality the sequences lyse bacteria including "superbugs" MRSA and VRE. Sequences with persistent chirality - homochiral sequences - assemble into antimicrobial pores and form contiguous helices that are biologically promiscuous and hemolytic. By contrast, heterochiral sequences that lack such persistence selectively attack bacterial membranes without oligomerising into visible pores. The results offer a mechanistic rationale for designing membrane-selective and sequence-independent antimicrobials.

Biointerphases, Dec 23, 2016

Engineered peptides capable of binding to silica have been used to provide contrast in chemical f... more Engineered peptides capable of binding to silica have been used to provide contrast in chemical force microscopy and tested for their capacity to selectively capture silica nanoparticles (NPs). Gold coated atomic force microscopy (AFM) microcantilevers with integrated tips and colloidal probes were functionalized with engineered peptides through a thiol group of a terminal cysteine which was linked via a glycine trimer to a 12-mer binding sequence. The functionalized probes demonstrated a significantly increased binding force on silicon oxide areas of a gold-patterned silicon wafer, whereas plain gold probes, and those functionalized with a random permutation of the silica binding peptide motif or an all-histidine sequence displayed similar adhesion forces to gold and silicon oxide. As the functionalized probes also allowed contact mode imaging subsequently to the adhesion mapping, also the associated friction contrast was measured and found to be similar to the adhesion contrast. F...

Journal of the American Chemical Society, Sep 21, 2016

A de novo topology of virus-like assembly is reported. The design is a trifaceted coiled-coil pep... more A de novo topology of virus-like assembly is reported. The design is a trifaceted coiled-coil peptide helix, which self-assembles into ultrasmall, monodisperse, anionic virus-like shells that encapsulate and transfer both RNA and DNA into human cells. Unlike existing artificial systems, these shells share the same physical characteristics of viruses being anionic, nonaggregating, abundant, hollow, and uniform in size, while effectively mediating gene silencing and transgene expression. These are the smallest virus-like structures reported to date, both synthetic and native, with the ability to adapt and transfer small and large nucleic acids. The design thus offers a promising solution for engineering bespoke artificial viruses with desired functions.

Chemical Engineering Journal, 2017

A modified graphene oxide-based Fenton's reaction has been investigated for the degradation of a ... more A modified graphene oxide-based Fenton's reaction has been investigated for the degradation of a challenging emerging contaminant which is not effectively removed in conventional water treatment. Metaldehyde, used as the challenge molecule in this study, is a common molluscicide that (like many highly soluble contaminants) has frequently breached European regulatory limits in surface waters. The new method involves graphene with higher hydrophilic characteristics (Single-Layer Graphene Oxide, SLGO) as a system that participates in a redox reaction with hydrogen peroxide and which can potentially stabilize the •OH generated, which subsequently breaks down organic contaminants. The modified Fenton's reaction has shown to be effective in degrading metaldehyde in natural waters (>92% removal), even at high contaminant concentrations (50 mg metaldehyde/L) and in the presence of high background organic matter and dissolved salts. The reaction is relatively pH insensitive. SLGO maintained its catalytic performance over 3 treatment cycles when immobilized. Its performance gradually decreased over time, reaching around 50% of starting performance on the 10 th treatment cycle. X-ray Photoelectron Spectroscopy (XPS) analysis of modifications caused in SLGO by the oxidizing treatment indicated that the oxidation of CC sp 2 to carbonyl groups may be the cause of the decrease in performance. The proposed modified Fenton's process has the potential to substitute traditional Fenton's treatment although regeneration of the nanocarbon is required for its prolonged use. Highlights:  SLGO and H 2 O 2 can degrade metaldehyde-contaminated water  pH and total organic carbon are not critical in the modified Fenton's process  SLGO has been immobilized and can be re-used  Regeneration of SLGO is needed to improve cost-effectiveness

Langmuir, 2015

I t has come to our attention that mutant NCAvd has one additional neutralizing mutation not ment... more I t has come to our attention that mutant NCAvd has one additional neutralizing mutation not mentioned in the article. In addition to mutations K9E, R124H, and K127E, mutant NCAvd also contains mutation R26N. However, this error does not have any effect on the results presented in the article.

Langmuir : the ACS journal of surfaces and colloids, Jan 17, 2015

We describe the development of a reference biosensor surface, based upon a binary mixture of olig... more We describe the development of a reference biosensor surface, based upon a binary mixture of oligo-ethylene glycol thiols, one of which has biotin at the terminus, adsorbed onto gold as self-assembled monolayers (SAMs). These surfaces were analyzed in detail by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) to establish the relationship between the thiol solution composition and the surface composition and structure. We report the use of argon cluster primary ions for the analysis of PEG-thiols, establishing that the different thiols are intimately mixed and that SIMS may be used to measure surface composition of thiol SAMs on gold with a detection limit better than 1% fractional coverage. The adsorption of neutralized chimeric avidin to these surfaces was measured simultaneously using ellipsometry and QCM-D. Comparison of the two measurements demonstrates the expected nonlinearity of the frequency response of the QCM but also reveals a strong vari...