Volume 1, Issue 1, June 2010

Professor Anthony P. F. Turner: An Innovative Educator And Pioneer Of Biosensors In The 21st Century (On His 60th Birth Anniversary)

Ashutosh Tiwari; Songjun Li; Yi Ge

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 2-3
DOI: 10.5185/amlett.2010.5102

The biosensors community would like to take this opportunity to pay rich tributes to Professor Anthony P. F. Turner for his pioneering research and notable contributions to this branch of science. Professor Turner, who is celebrating his 60th birthday on June 5, 2010, is a distinguished professor, scientist and academician with an illustrious scientific career that spans more than 30 years. He has contributed extensively to various aspects of biosensors and biomimetic sensors.

A PH-responsive, Low Crosslinked, Molecularly Imprinted Insulin Delivery System

Songjun Lia; Ashutosh Tiwari; Yi Gec; Dan Fei

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 4-10
DOI: 10.5185/amlett.2010.4110

A new type of insulin delivery system capable of better self-regulating the release of insulin was reported in this study. This insulin delivery system was made of a low crosslinked insulin-imprinted hydrogel that exhibited pH-dependent interpolymer interactions between poly(methacrylic acid) (PMAA) and poly(ethylene glycol) (PEG). At acidic conditions (such as pH 3.5), this delivery system resembled a highly crosslinked imprinted hydrogel and demonstrated a relatively slow release due to the formation of the PMAA-PEG complexes, which significantly increased physical crosslinking within the hydrogel interior and largely fixed the imprinted networks. On the contrary, at neutral or basic conditions (such as pH 7.4), this delivery system was comparable to a non-imprinted hydrogel and caused a rapid release resulting from the dissociation of the PMAA-PEG complexes. Unlike previously reported non-imprinted hydrogels and highly crosslinked imprinted polymers, which lack either molecular recognition ability or switchable imprinted networks, this unique insulin delivery system was composed of tunable and low crosslinked imprinted networks, which thereby enabled better self-regulation of insulin delivery.

Carboxymethyl Chitosan And Its Applications

V.K Mourya; Nazma N. Inamdara;Ashutosh Tiwari

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 11-33
DOI: 10.5185/amlett.2010.3108

Deacetylation of chitin affords chitosan, a polymer, widely studied for its pharmaceutical and nonpharmaceutical applications. The hurdle in comprehending these applications is its limited solubility. Carboxymethylation of chitosan helps to surmount this hurdle with its improved solubility in water. Though there is ample of research related to carboxymethyl chitosan (CMC) the focused review of the topic is unavailable. Hence an attempt is made in this review to cover the recent findings pertaining to synthesis, characterization of CMC and its applications especially in pharmaceutical field. CMC has been synthesized by ways as direct alkylation, reductive alkylation, Michael addition and characterized by FTIR, NMR spectroscopy, and DSC, titrimetry, viscometry, gel permeation chromatography, X-ray diffraction and capillary zone electrophoresis. The carboxymethyl group can be present at O or N or both the atoms of chitosan molecule. The CMC possess modulated physical and biological properties as chelating, sorption, moisture retention, cell functioning antioxidant, antibacterial, antiapoptotic etc. CMC is used in sustained or controlled release drug delivery, pH responsive drug delivery, DNA delivery as permeation enhancer etc. CMC can be further modified with alkylation, acylation, and grafting. Carboxyalkylation of chitosan yield carboxyethyl, carboxybutyl chitosans. These analogues of CMC may be helpful in substantiating the applications of chitosan.

Studies On The Interaction Of DNA With Vitamin B12 Based On The Immobilization Of DsDNA On Nano-scale Hydroxyapatite Coating

Nuo Zhang; Caixia Xu; Qin Wei; Bin Du; Ru Li; Tianguo Zhang; Dan Wu; Yuxue Dai

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 34-39
DOI: 10.5185/amlett.2010.3104

Nano-scale hydroxyapatite (HAp) was prepared by combining co-precipitation with microemulsion method, which exhibited strong adsorption for DNA due to its excellent biocompatibility and particular adsorbability. DNA and HAp could be modified onto glassy carbon electrode (GCE) by the simple and convenient “tip-coating” method. Cyclic voltammetry was used to investigate the interaction of DNA immobilized on the HAp film with vitamin B12 (VB12). The existence of DNA led to the decrease of reduction current of VB12. Both the electron transfer coefficient (α) and the standard rate constant (ks) were different obtained on GCE and dsDNA/HAp/GCE, which indicated the formation of an electrochemical inactive super molecular complex DNA-nVB 12 . The equilibrium constant of this complex was calculated to be 5.35 × 10 5 mol·L -1 and the binding number between DNA and VB12 of the complex were determined to be one.

Adsorption Behavior of Potato Starch-silica Nanobiocomposite

Vandana Singha; Sadanand Pandeya;Rashmi Sanghib; Somit Kumar Singha

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 40-47
DOI: 10.5185/amlett.2010.4107

In continuation to our recent study on the synthesis and characterization of starch-silica nanocomposite, in the present study the nanocomposite has been evaluated for the removal of Cd(II) from the aqueous solution. The conditions for the sorption have been optimized and kinetic and thermodynamic studies were performed to understand the adsorption behaviour of the composite. Though the cadmium sorption by the nanocomposite takes place in wide pH range, pH 7.5 was found most favorable and at this pH the adsorption equlibrium data were modeled using the Langmuir and Freundlich isotherms at 10°C, 20°C, 30°C and 40°C. At all the temperatures, the data fitted more satisfactorily to Langmuir isotherm indicating unilayer adsorption. Based on Langmuir model, Qmax was calculated to be 769.23 mg/g. The adsorption showed pseudo second order kinetics with a rate constant of 5.65 × 10 -5 g mg -1 min -1 (at 100 mg/L initial Cd(II) concentration) indicating chemisorption. The thermodynamic study revealed the endothermic and spontaneous nature of the adsorption. Effect of electrolyte on the adsorption was also studied. The nanocomposite was sucessfully recycled for six consecutive adsorption-desorption cycles with only a marginal loss in its efficiency indicating its high reusability. The composite was found to be a highly stable photoluminescent Cd(II) adsorbent which may be suitable for sensor applications in detecting the metal ions both in vivo and vitro as the material is natural polymer based.

Electrochemical DNA Biosensor For The Detection Of Sanguinarine In Adulterated Mustard Oil

Ravindra P. Singh; Da-Yeon Kang; Jeong-Woo Choi

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 48-54
DOI: 10.5185/amlett.2010.3106

PANi/ClO4 doped films were developed electrochemically to immobilize DNA as biosensing platform to detect sanguinarine from adulterated mustard oils. The principle of technique was based on the interaction/intercalation of sanguinarine with dsDNA using electrochemical method. Further, it was suggested that sanguinarine intercalates with DNA strands forming complexes, results in the decrease of redox peak currents. In addition, the decrease of the peak current is proportional to the concentration of sanguinarine. The results based on the voltammetric signals decreased in concomitant increase of sanguinarine concentrations due to base pairing in dsDNA. The bioelectrode exhibited the detection limits 2–64 μM. The recovery experiment results found between 89% and 121% from spiked edible mustard oil sources. The correlation found between the current vs. concentration of SA with a correlation coefficient of (r 2 ) of 0.995 at 95% confidence limit. UV–VIS, CV, DPV, AFM, and SEM. characterized the bioelectrodes. Thus, the proposed electrochemical DNA biosensor detected SA and promising for real-time analysis of small molecules of environmental interest.

Study Of Structural And Electrical Properties Of Pure And Zn-Cu Doped SnO2

Radheshyam Rai

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 55-58
DOI: 10.5185/amlett.2010.3101

Numerous metal oxide semiconductor materials were reported to be usable as semiconductor gas sensor, such as ZnO, SnO2, and TiO2 and so on. The samples of Zn and Cu doped SnO2 (SnZnO3 and SnCuO3) have been synthesized by solid-state reaction method. Some aspect of crystal structure of the compound at room temperature was studied using X-ray diffraction technique. The XRD study of the compound shows that there is a change in the basic crystal structure of SnO2 on substitutions of ZnO and CuO. The patterns of the SnO2 sample are indexed as tetragonal perovskite type with a = 7.3928 Å, c = 5.2879 Å but on substitution of ZnO and CuO the structure becomes orthorhombic with lattice constant a = 23.5237Å, b = 8.2183 Å and c =5.8017 Å or a = 21.8594 Å, b = 5.3200 Å, and c = 5.1803 Å, respectively. The temperature variation of resistance shows that compounds have negative temperature coefficient of resistance. The gas sensitivity for LPG (liquefied petroleum gas) showed a drastic change in conductivity.

Microwave Assisted Synthesis Of Chitosan-graft-styrene For Efficient Cr(VI) Removal

Ajit Kumar Sharma;Ajay Kumar Mishra

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 59-66
DOI: 10.5185/amlett.2010.4120

In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar condition of concentration of styrene and chitosan, 148% grafting was observed with potassium persulphate (K2S2O8)/ascorbic acid as redox initiator and atmospheric oxygen as co-catalyst in 1 h using conventional method at 35 o C. Microwave synthesized Ch-g-sty copolymer was characterized by Fourier transform-Infrared (FTIR) spectroscopy, thermo gravimetric analysis (TGA), X-ray diffraction (XRD) measurement and scanning electron microscopy (SEM). Maximum grafting was optimized by varying the microwave power, exposure time and styrene/chitosan concentration. Ch-g-sty copolymer was found to be more efficient for Cr(VI) removal as compare to conventionally and parent chitosan in aqueous solution. Sorption of Cr(VI) was depending upon pH and concentration, with pH=3 being the optimum value. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 526.3 mg/g, 312.5 mg/g and 166.7 mg/g for Ch-g-sty copolymer, conventional (thermostatic water bath) method and parent chitosan respectively.

Characterization Of Chitosan-chondroitin Sulfate Blended Membranes And Effects On The Growth Of Corneal Cells

Zi-Ang Yao;Hai-Ge Wu

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 67-74
DOI: 10.5185/amlett.2010.4113

In order to construct a suitable scaffold for corneal cell culture and transplantation in vitro, different chitosan-chondroitin sulfate blended membranes were prepared and the properties of blended membranes were studied. Corneal stroma cells and corneal endothelial cells were seeded onto the blended membrane surface and the effects of the blended membranes on corneal cell attachment and metabolism were investigated. The results showed that chitosan and chondroitin sulfate had good compatibility in blended membranes. Chondroitin sulfate improved the homogeneousness, crystallization, transparency, and tensile strength and decreased the water content of the blended membrane. Within the blending ratio of 1:0.1, chondroitin sulfate reduced the damage of chitosan membranes to cells and improved the biocompatibility between cells and membranes. Corneal cells grew and formed a confluent monolayer on chitosan-chondroitin sulfate blended membranes (CH-CS3). All results indicated that the blended membranes of chitosan and chondroitin sulfate could be used as a scaffold for corneal cell culture in vitro and have potential to be used as carriers for corneal endothelial cell transplantation.

In-situ Coating Of MWNTs With Solgel TiO2 Nanoparticles

Li Chen; Guangshui Yua;Jianming Zhanga; Xiujiang Pangb

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 75-78
DOI: 10.5185/amlett.2010.4117

Multi-walled carbon nanotubes (MWNTs) were in-situ coated with anatase TiO2 via sol-gel process followed by annealing of the composites using infrared (IR) lamp. SEM results showed that MWNTs were coated with 15-45 nm thick TiO2 layer depending on the composite ratios. Based on the XRD results, MWNTs were found to show heterogeneous nucleation for anatase TiO2 and promote the formation of larger anatase TiO2 crystalline particles with higher crystalline degree. The UV-Vis- NIR characterization indicated the MWNTs also enhanced the sensitivity of TiO2 matrix for both UV and visible light, and the bond edge absorption position of the TiO2  composites shifted toward higher wavelengths with the decrease of MWNTs content. The method could be utilized to fabricate MWNTs /TiO2 composites conveniently.

Structural And Dielectric Properties Of Dy2(Ba0.5R0.5)2O7 (R = W, Mo) Ceramics

N. K. Singh; Pritam Kumar; Hemchand Kumar; Radheshyam Rai

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 79-82
DOI: 10.5185/amlett.2010.3102

The polycrystalline samples of the pyrochlore-type Dy2(Ba0.5R0.5)2O7 (R = W, Mo) compounds have been prepared by a high-temperature solid-state reaction technique. Preliminary X-ray diffraction (XRD) studies and scanning electron micrographs (SEM) of the compounds at room temperature suggested that compounds have single phase orthorhombic crystal structures and grain distribution throughout the surface of the samples was uniform. Dielectric studies (dielectric constant (e´) and tangent loss (tan δ) obtained both as a function of frequency (4 kHz -1 MHz) at room temperature (RT) and temperature (RT 320 0 C) at 20 kHz and 100 kHz suggest that compounds do not have dielectric anomaly in the said frequency and temperature range.

Bio- Nanomaterials For Versatile Bio- Molecules Detection Technology

Ravindra P. Singh;Jeong-Woo Choi

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 83-84
DOI: 10.5185/amlett.2010.4109

Over the past few years, bionanomaterial research has emerged as a new exciting field and the importance of DNA, RNA and peptides in designing bionanomaterials for the fundamental development in biotechnology and nanomaterials has begun to be recognized as a new interdisciplinary frontier in field of life science and material science. Great advances in nanobiochip materials, nanoscale biomimetic materials, nanomotors, nanocomposite materials, interface biomaterials, and nanobiosensor and nano drug delivery systems have enormous prospect in industrial, defense, and clinical medicine applications. Bio-molecules are very important elements in nanoscience and nanotechnology. Peptide nucleic acids (PNAs) replace DNA as a probe for biomolecular tool in the molecular genetics diagnostics, cytogenetic, and various pharmaceutical potentials as well as for the development of sensors/arrays/chips and many more purposes.

Welcome Message

Anthony P. F. Turner

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages -
DOI: 10.5185/amlett.2010.5110

I am delighted to welcome you to the first issue of Advanced Materials Letters published by VBRI press. Publishing periodically undergoes small revolutions and we can see a plethora of activities at the current time, which are attempting to satisfy the voracious appetite of rapidly expanding sectors. Advanced Materials is one such area where advances in molecular science, chemistry and engineering are furnishing multifarious opportunities that will underpin new products and process for a wide variety of applications in medicine, the food industry, environmental materials and microfabrication. Such facilitating science is essential for the development of emerging areas such as plastic electronics, bionics, synthetic biology, energy harvesting and biodegradable materials.