Publications by authors named "Abhijit Biswas"

29 Publications

  • Page 1 of 1

Modeling Drug Absorption from the Dermis after an Injection.

J Pharm Sci 2021 03 25;110(3):1279-1291.e1. Epub 2020 Nov 25.

Temple University, Department of Mathematics, 1805 N Broad Street, Philadelphia, PA 19122, USA. Electronic address:

A dermal absorption model for small and macromolecules was previously proposed by Ibrahim et al. This model estimated absorption of therapeutics from the dermal tissue based on their molecular size and protein binding through blood and lymphatics. Blood absorption followed a two-pore theory and the lymphatic absorption was limited by the constant lymphatic flow rate. Current work builds on this steady-state concept by modeling the absorption from the dermis immediately after an injection is given (unsteady state). An injection in the dermis creates a localized pressure gradient which resolves itself over time. This phenomenon is captured in the model to estimate the impact of injection volume on the absorption rate constant. Blood absorption follows the two-pore theory but is time-dependent and the lymphatic absorption is determined based on valve opening and pressure driven convective flow, returning to steady-state as the molecule is absorbed. A direct comparison of the steady-state analysis, experimental data and the current model is made. The results indicate that accounting for the localized time-varying pressure can better predict the experimental absorption rate constants. This work significantly improves the existing understanding of macromolecule uptake from the interstitial fluid following intradermal injection.
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http://dx.doi.org/10.1016/j.xphs.2020.10.042DOI Listing
March 2021

Enhanced accumulation of reduced glutathione by Scopoletin improves survivability of dopaminergic neurons in Parkinson's model.

Cell Death Dis 2020 09 10;11(9):739. Epub 2020 Sep 10.

Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.

Parkinson's disease (PD) is a neuromotor disorder, primarily manifested by motor anomalies due to progressive loss of dopaminergic neurons. Although alterations in genetic factors have been linked with its etiology, exponential accumulation of environmental entities such as reactive oxygen species (ROS) initiate a cyclic chain reaction resulting in accumulation of cellular inclusions, dysfunctional mitochondria, and overwhelming of antioxidant machinery, thus accelerating disease pathogenesis. Involvement of oxidative stress in PD is further substantiated through ROS induced Parkinsonian models and elevated oxidative markers in clinical PD samples; thereby, making modulation of neuronal oxidative load as one of the major approaches in management of PD. Here we have found a potent antioxidant moiety Scopoletin (Sp), a common derivative in most of the nootropic herbs, with robust neuroprotective ability. Sp increased cellular resistance to ROS through efficient recycling of GSH to prevent oxidative damage. The Sp treated cells showed higher loads of reduced glutathione making them resistant to perturbation of antioxidant machinery or neurotoxin MPP. Sp could restore the redox balance, mitochondrial function, and prevented oxidative damage, leading to recovery of dopaminergic neural networks and motion abilities in Drosophila genetic model of PD. Our data also suggest that Sp, in combination increases the therapeutic potency of L-DOPA by mitigating its chronic toxicity. Together, we highlight the possible ability of Sp in preventing oxidative stress mediated loss of dopaminergic neurons and at the same time enhance the efficacy of dopamine recharging regimens.
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http://dx.doi.org/10.1038/s41419-020-02942-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7484898PMC
September 2020

Dynamics of Photo-Generated Carriers across the Interface between CsPbBr Nanocrystals and Au-Ag Nanostructured Film, and Its Control via Ultrathin MgO Interface Layer.

ACS Omega 2020 Jun 18;5(21):11915-11922. Epub 2020 May 18.

Department of Physics and Centre for Energy Science, Indian Institute of Science Education and Research (IISER), Pune, Pune, Maharashtra 411008, India.

The dynamics and control of charge transfer between optoelectronically interesting and size-tunable halide perovskite quantum dots and other juxtaposed functional electronic materials are important issues for the emergent device interest involving such a family of materials in heterostructure configurations. Herein, we have grown bimetallic Au-Ag thin films on glass by pulsed laser deposition at room temperature, which bear nanoparticulate character, and the corresponding optical absorption spectra reveal the expected surface plasmon resonance signature(s). Subsequently, spin-coated CsPbBr nanoparticle films onto the bimetallic Au-Ag films exhibit surface-enhanced Raman scattering as well as strong photoluminescence quenching, the latter reflecting highly efficient transfer of photo-generated carriers across the CsPbBr/Au-Ag interface. Surprisingly, when an ultrathin MgO (insulating) layer of optimum thickness is introduced between the CsPbBr and Au-Ag films, the charge transfer is further facilitated with the average lifetime of carriers becoming even shorter. By changing the thickness of the thin MgO layer, the carrier lifetime can in fact be tuned; with the charge transfer getting fully blocked for thick enough MgO layers, as expected. Our study thus throws light on the charge-carrier dynamics in halide perovskites, which is of importance to emergent optoelectronic applications.
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http://dx.doi.org/10.1021/acsomega.9b03817DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7271035PMC
June 2020

Designing a new family of oxonium-cation based structurally diverse organic-inorganic hybrid iodoantimonate crystals.

Chem Commun (Camb) 2019 Jul 13;55(52):7562-7565. Epub 2019 Jun 13.

Department of Physics and Centre for Energy Science, Indian Institute of Science Education and Research, Pune, Pune-411008, Maharashtra, India.

Several new structurally diverse carbonyl functional group-based iodoantimonate organic-inorganic hybrid crystals are synthesized using an in situ formed oxonium cationic precursor. These crystals exhibit interesting optoelectronic properties consistent with DFT calculations. Charge transfer and photoluminescence quenching between these crystals and Au nanoparticulate films are examined for potential application interest.
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http://dx.doi.org/10.1039/c9cc03485dDOI Listing
July 2019

Engineered Histidine-Enriched Facial Lipopeptides for Enhanced Intracellular Delivery of Functional siRNA to Triple Negative Breast Cancer Cells.

ACS Appl Mater Interfaces 2019 Feb 24;11(5):4719-4736. Epub 2019 Jan 24.

Computational Science Division , Saha Institute of Nuclear Physics, Kolkata , 1/AF Bidhannagar , Kolkata 700064 , India.

Cytosolic delivery of functional siRNA remains the major challenge to develop siRNA-based therapeutics. Designing clinically safe and effective siRNA transporter to deliver functional siRNA across the plasma and endosomal membrane remains a key hurdle. With the aim of improving endosomal release, we have designed cyclic and linear peptide-based transporters having an Arg-His-Arg template. Computational studies show that the Arg-His-Arg template is also stabilized by the Arg-His side-chain hydrogen bonding interaction at physiological pH, which dissociates at lower pH. The overall atomistic interactions were examined by molecular dynamics simulations, which indicate that the extent of peptide_siRNA assembly formation depends greatly on physicochemical properties of the peptides. Our designed peptides having the Arg-His-Arg template and two lipidic moieties facilitate high yield of intracellular delivery of siRNA. Additionally, unsaturated lipid, linoleic acid moieties were introduced to promote fusogenicity and facilitate endosomal release and cytosolic delivery. Interestingly, such protease-resistant peptides provide serum stability to siRNA and exhibit high efficacy of erk1 and erk2 gene silencing in the triple negative breast cancer (TNBC) cell line. The peptide having two linoleyl moieties demonstrated comparable efficacy with commercial transfection reagent HiPerFect, as evidenced by the erk1 and erk2 gene knockdown experiment. Additionally, our study shows that ERK1/2 silencing siRNA and doxorubicin-loaded gramicidin-mediated combination therapy is more effective than siRNA-mediated gene silencing-based monotherapy for TNBC treatment.
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http://dx.doi.org/10.1021/acsami.8b13794DOI Listing
February 2019

Serratus Plane Block: A Cadaveric Study to Evaluate Optimal Injectate Spread.

Reg Anesth Pain Med 2018 Nov;43(8):854-858

Department of Anesthesia, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.

Background And Objectives: Although serratus plane block reportedly provides satisfactory analgesia for breast and thoracic surgeries, the optimal technique for consistent success has not been studied. The goal of this anatomical study was to evaluate the impact of volume, level, and site of injection on the extent of injectate spread that can influence anesthetic coverage.

Methods: Ultrasound-guided dye injection and subsequent dissection were performed in 39 cadaveric hemithoraces. Methylene blue was injected according to 1 of 4 injection protocols as follows: one 20-mL bolus, either superficial or deep to the serratus anterior muscle (SAM), at the fifth rib level (groups SUP-20 and DEEP-20, respectively), or two 20-mL boluses, either superior or deep to the SAM, one at the third rib and one at the fifth rib level (group SUP-40 and group DEEP-40, respectively). Following injection, dissection and 3-dimensional digitization were performed to map the area of dye spread.

Results: We found that the extent of dye spread was mostly influenced by the volume of injection rather than the plane of injection (superficial vs deep to SAM). Increasing the volume from 20 to 40 mL doubled the area of injectate spread and promoted dye spread preferentially to the anterior chest wall, with some impact on cephalad-to-caudad spread and no impact on posterior spread. Dye was found most consistently in the axilla when a separate injection was performed at the third rib level.

Conclusions: Our data showed that a high-volume double-injection technique provides extensive and consistent dye spread in the anterior chest wall and axilla, regardless of the plane of injection relative to the SAM. This technique likely provides more reliable analgesic coverage for breast procedures especially those that involve the axilla, pending confirmation in future clinical studies.
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http://dx.doi.org/10.1097/AAP.0000000000000848DOI Listing
November 2018

Use of Serratus Plane Block for Repair of Coarctation of Aorta: A Report of 3 Cases.

Reg Anesth Pain Med 2018 Aug;43(6):641-643

Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.

Objectives: The practice of regional anesthesia techniques (thoracic, epidural, paravertebral) in pediatric cardiac surgery enhances perioperative outcomes such as improved perioperative analgesia, decreased stress response, early extubation, and shortened hospital stay. However, these blocks can be technically challenging and can be associated with unacceptable failure rate and complications in infants. For these reasons, regional anesthesia is sometimes avoided in pediatric cardiac surgery. We describe the simple and effective serratus plane block for thoracotomy analgesia in 2 neonates and a child.

Case Report: We present 3 pediatric patients, each of whom was having coarctation repair and received an ultrasound-guided serratus plane block for thoracotomy analgesia. The patients were 3 days, 14 days, and 4 years old, weighing from 1.9 to 16 kg. The serratus plane block was performed prior to surgical incision. The block was technically simple compared with thoracic epidural or paravertebral block. All patients were extubated immediately after completion of surgery. Apart from the induction dose of fentanyl (2 μg/kg), no further opioids were required intraoperatively. Postoperative opioid requirements as well as duration of intensive care and hospital stay were lower than recent averages (for the same demographic and procedure) in our hospital.

Conclusions: We propose that the serratus plane block is a simple procedure that provides good perioperative analgesia for infant thoracotomy, potentially facilitating early extubation and a shorter hospital stay.
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http://dx.doi.org/10.1097/AAP.0000000000000801DOI Listing
August 2018

Relative Contributions of Adductor Canal Block and Intrathecal Morphine to Analgesia and Functional Recovery After Total Knee Arthroplasty: A Randomized Controlled Trial.

Reg Anesth Pain Med 2018 Feb;43(2):154-160

From the Department of Anesthesia and Pain Management, Toronto Western Hospital, University Health Network, Toronto, Canada.

Background And Objectives: Effective postoperative analgesia may enhance early rehabilitation after orthopedic surgery. This randomized double-blind trial investigates the relative contributions of adductor canal block and low-dose intrathecal morphine (ITM) to postoperative analgesia and functional recovery after total knee arthroplasty.

Methods: Two-hundred one patients undergoing elective unilateral total knee arthroplasty under spinal anesthesia were randomized to 3 groups. All patients received standardized intraoperative local infiltration analgesia and postoperative oral analgesics. Patients in group 1 received a "sham" adductor canal block with 30 mL of normal saline. Patients in group 2 received an adductor canal block with 30 mL of ropivacaine 0.5% with 1:400,000 epinephrine, whereas patients in group 3 received the adductor canal block with the active drug and 100 μg of ITM. The primary outcome measure was the Timed Up and Go (TUG) test on the second postoperative day. Secondary outcomes included postoperative pain scores and opioid requirements, distance walked, time to hospital discharge, and self-reported functional outcomes at 3 months.

Results: All 3 groups had similar values of TUG test on postoperative day (POD) 2 (46 [36-62], 45 [33-61], and 52 [41-69]; P = 0.166) as well as other short-term and 3-month functional outcomes. Patients in group 3 showed a favorable analgesic profile as evidenced by 3 positive secondary outcomes. These positive outcomes were lower pain scores 12 hours postoperatively both at rest (4 [2-6.3], 4 [2.3-6], and 3 [1-4]; P = 0.007) and on movement (6 [4-8], 6 [3-8], and 4 [2-6]; P = 0.002), a lower incidence of "rescue" intravenous patient-controlled analgesia (42%, 34%, and 20%; P = 0.031), and the lowest cumulative opioid requirements for the first 48 hours postoperatively (86 ± 71, 68 ± 46, and 59 ± 39; P < 0.005, group 3 compared with group 1).

Conclusions: Our data suggest that there is no difference in either the primary outcome of TUG test on POD 2, other immediate functional secondary outcomes, or in global functional outcome at 3 months postoperatively across all 3 groups. Our data also suggest an improved analgesic profile in the first 48 hours postoperatively when both adductor canal block and low-dose ITM (100 μg) are added to local infiltration analgesia as evidenced by several positive secondary outcomes of lower pain scores and opioid requirements.

Clinical Trial Registration: This study was registered at ClinicalTrials.gov, identifier NCT02411149.
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http://dx.doi.org/10.1097/AAP.0000000000000724DOI Listing
February 2018

Adaptive optics correction into single mode fiber for a low Earth orbiting space to ground optical communication link using the OPALS downlink.

Opt Express 2015 Dec;23(26):33705-12

An adaptive optics (AO) testbed was integrated to the Optical PAyload for Lasercomm Science (OPALS) ground station telescope at the Optical Communications Telescope Laboratory (OCTL) as part of the free space laser communications experiment with the flight system on board the International Space Station (ISS). Atmospheric turbulence induced aberrations on the optical downlink were adaptively corrected during an overflight of the ISS so that the transmitted laser signal could be efficiently coupled into a single mode fiber continuously. A stable output Strehl ratio of around 0.6 was demonstrated along with the recovery of a 50 Mbps encoded high definition (HD) video transmission from the ISS at the output of the single mode fiber. This proof of concept demonstration validates multi-Gbps optical downlinks from fast slewing low-Earth orbiting (LEO) spacecraft to ground assets in a manner that potentially allows seamless space to ground connectivity for future high data-rates network.
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http://dx.doi.org/10.1364/OE.23.033705DOI Listing
December 2015

Molecular diagnostics of neurodegenerative disorders.

Front Mol Biosci 2015 22;2:54. Epub 2015 Sep 22.

Department of Electrical Engineering, Center for Nano Science and Technology, University of Notre Dame Notre Dame, IN, USA.

Molecular diagnostics provide a powerful method to detect and diagnose various neurological diseases such as Alzheimer's and Parkinson's disease. The confirmation of such diagnosis allows early detection and subsequent medical counseling that help specific patients to undergo clinically important drug trials. This provides a medical pathway to have better insight of neurogenesis and eventual cure of the neurodegenerative diseases. In this short review, we present recent advances in molecular diagnostics especially biomarkers and imaging spectroscopy for neurological diseases. We describe advances made in Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD), and finally present a perspective on the future directions to provide a framework for further developments and refinements of molecular diagnostics to combat neurodegenerative disorders.
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http://dx.doi.org/10.3389/fmolb.2015.00054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4585189PMC
October 2015

Sunlight induced unique morphological transformation in graphene based nanohybrids: appearance of a new tetra-nanohybrid and tuning of functional property of these nanohybrids.

Soft Matter 2015 Jun;11(21):4226-34

Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700032, India.

In this study, sunlight was used for in situ preparation of gel-based various nanohybrid systems. A naturally occurring amino acid, l-phenylalanine derivative formed a hydrogel with graphene oxide (GO)/reduced graphene oxide (rGO) at physiological pH. This hydrogel was then used in the presence of silver ions and diffuse sunlight to form initially a tri-nanohybrid system consisting of six atom silver nanoclusters, nanosheets, and nanofibers. Interestingly, a time-dependent morphological transformation occurs in this nanohybrid system to form one tri-nanohybrid to another tri-nanohybrid with the appearance of a novel, nanoscopic intermediate tetra-nanohybrid system consisting of four distinctly different nanomaterials (nanofibers, nanosheets, nanospheres, and nanoparticles). UV-Vis and fluorescence spectroscopic analyses, transmission electron microscopic, X-ray photo electron spectroscopic and MALDI-TOF mass spectral analyses with time were applied to characterise these morphological transformations in gel based nanohybrids. Time-dependent X-ray photo electron spectroscopic (XPS) analysis was used to uncover the mechanism for the transformation of silver nanoclusters to silver nanoparticles in the hydrogel matrix. Sunlight was used to trigger time-dependent structural transformation in the nanohybrid systems. Interestingly, one of these tri-nanohybrid systems (silver nanoparticles containing rGO based hydrogel) shows a catalytic property of reducing nitroarenes to aminoarenes and the catalytic efficiency can be modulated by changing the size of the silver nanoparticles with time in diffuse sunlight. The mechanism for different catalytic activities for different hybrids with varying size of silver nanoparticles has also been deciphered.
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http://dx.doi.org/10.1039/c5sm00359hDOI Listing
June 2015

Vibrotactile sensitivity threshold: nonlinear stochastic mechanotransduction model of the Pacinian Corpuscle.

IEEE Trans Haptics 2015 Jan-Mar;8(1):102-13. Epub 2014 Nov 11.

Based on recent discoveries of stretch and voltage activated ion channels in the receptive area of the Pacinian Corpuscle (PC), this paper describes a two-stage mechanotransduction model of its near threshold Vibrotactile (VT) sensitivity valid over 10 Hz to a few kHz. The model is based on the nonlinear and stochastic behavior of the ion channels represented as dependent charge sources loaded with membrane impedance. It simulates the neural response of the PC considering the morphological and statistical properties of the receptor potential and action potential with the help of an adaptive relaxation pulse frequency modulator. This model also simulates the plateaus and nonmonotonic saturation of spike rate characteristics. The stochastic simulation based on the addition of mechanical and neural noise describes that the VT Sensitivity Threshold (VTST) at higher frequencies is more noise dependent. Above 800 Hz even a SNR = 150 improves the neurophysiological VTST more than 3 dBμ. In that frequency range, an absence of the entrainment threshold and a lower sensitivity index near the absolute threshold make the upper bound of the psychophysical VTST more dependent on the experimental protocol and physical set-up. This model can be extended to simulate the neural response of a group of PCs.
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http://dx.doi.org/10.1109/TOH.2014.2369422DOI Listing
November 2015

Multiscale layered biomechanical model of the pacinian corpuscle.

IEEE Trans Haptics 2015 Jan-Mar;8(1):31-42. Epub 2014 Nov 11.

This paper describes a multiscale analytical model of the lamellar structure and the biomechanical response of the Pacinian Corpuscle (PC). In order to analyze the contribution of the PC lamellar structure for detecting high-frequency vibrotactile (VT) stimuli covering 10 Hz to a few kHz, the model response is studied against trapezoidal and sinusoidal stimuli. The model identifies a few generalizable features of the lamellar structure which makes it scalable for different sizes of PC with different number of lamellae. The model describes the mechanical signal conditioning of the lamellar structure in terms of a recursive transfer-function, termed as the Compression-Transmittance-Transfer-Function (CTTF). The analytical results show that with the increase of the PC layer index above 15, the PC inner core (IC) relaxes within 1 ms against step compression of the outermost layer. This model also considers the mass of each PC layer to investigate its effect on the biomechanical response of the lamellar structure. The interlamellar spacing and its biomechanical properties along with the model response are validated with experimental data in the literature. The proposed model can be used for simulating a network of PCs considering their diversity for analyzing the high-frequency VT sensitivity of the human skin.
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http://dx.doi.org/10.1109/TOH.2014.2369416DOI Listing
November 2015

Tailored synthesis of various nanomaterials by using a graphene-oxide-based gel as a nanoreactor and nanohybrid-catalyzed C-C bond formation.

Chem Asian J 2014 Dec 15;9(12):3451-6. Epub 2014 Sep 15.

Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700032 (India), Fax: (+91) 33-2473-2805.

New graphene oxide (GO)-based hydrogels that contain vitamin B2/B12 and vitamin C (ascorbic acid) have been synthesized in water (at neutral pH value). These gel-based soft materials have been used to synthesize various metal nanoparticles, including Au, Ag, and Pd nanoparticles, as well as nanoparticle-containing reduced graphene oxide (RGO)-based nanohybrid systems. This result indicates that GO-based gels can be used as versatile reactors for the synthesis of different nanomaterials and hybrid systems on the nanoscale. Moreover, the RGO-based nanohybrid hydrogel with Pd nanoparticles was used as an efficient catalyst for C-C bond-formation reactions with good yields and showed high recyclability in Suzuki-Miyaura coupling reactions.
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http://dx.doi.org/10.1002/asia.201402695DOI Listing
December 2014

Applications of surface-enhanced Raman scattering in advanced bio-medical technologies and diagnostics.

Drug Metab Rev 2014 May 27;46(2):155-75. Epub 2014 Jan 27.

Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock , Little Rock, AR , USA .

In this review of the literature on surface-enhanced Raman scattering (SERS), we describe recent developments of this technique in the medical field. SERS has developed rapidly in the last few years as a result of the fascinating advancements in instrumentation and the ability to interpret complex Raman data using high-processional, computer-aided programs. This technique, has many advantages over ordinary spectroscopic analytical techniques - such as extremely high sensitivity, molecular selectivity, intense signal and great precision - that can be leveraged to address complex medical diagnostics problems. This review focuses on the SERS-active substrate, as well as major advances in cancer and bacteria detection and imaging. Finally, we present a perspective on anticipated future advancements in SERS techniques to address some of the most critical challenges in the areas of diagnostics, detection, and sensing.
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http://dx.doi.org/10.3109/03602532.2013.873451DOI Listing
May 2014

Advances in bionanomaterials for bone tissue engineering.

J Nanosci Nanotechnol 2013 Jan;13(1):1-22

Center for Nano Science and Technology, Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.

Bone is a specialized form of connective tissue that forms the skeleton of the body and is built at the nano and microscale levels as a multi-component composite material consisting of a hard inorganic phase (minerals) in an elastic, dense organic network. Mimicking bone structure and its properties present an important frontier in the fields of nanotechnology, materials science and bone tissue engineering, given the complex morphology of this tissue. There has been a growing interest in developing artificial bone-mimetic nanomaterials with controllable mineral content, nanostructure, chemistry for bone, cartilage tissue engineering and substitutes. This review describes recent advances in bionanomaterials for bone tissue engineering including developments in soft tissue engineering. The significance and basic process of bone tissue engineering along with different bionanomaterial bone scaffolds made of nanocomposites and nanostructured biopolymers/bioceramics and the prerequisite biomechanical functions are described. It also covers latest developments in soft-tissue reconstruction and replacement. Finally, perspectives on the future direction in nanotechnology-enabled bone tissue engineering are presented.
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http://dx.doi.org/10.1166/jnn.2013.6733DOI Listing
January 2013

Control of the size and shape of TiO2 nanoparticles in restricted media.

Nanotechnology 2013 May 12;24(19):195601. Epub 2013 Apr 12.

Department of Chemistry, University of Kalyani, Kalyani, West Bengal, India.

Template-capped TiO2 nanostructures have been synthesized. In certain template conditions, TiO2 hexagons are found to form. These hexagonal structures can be effectively sensitized by fluorescein dye without any change in the protonation state of the dye. Bare TiO2 nanoparticles are not so useful for sensitization with dyes like fluorescein as they alter the dye protonation state. The novelty of this work is twofold-the hitherto elusive hexagonal phase of TiO2 nanoparticles has been stabilized and the synthesis of TiO2 in the rutile phase has been achieved under mild conditions.
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http://dx.doi.org/10.1088/0957-4484/24/19/195601DOI Listing
May 2013

A gel-based trihybrid system containing nanofibers, nanosheets, and nanoparticles: modulation of the rheological property and catalysis.

Angew Chem Int Ed Engl 2013 May 8;52(19):5041-5. Epub 2013 Apr 8.

Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.

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http://dx.doi.org/10.1002/anie.201301128DOI Listing
May 2013

Bionanomaterials for bone tumor engineering and tumor destruction.

J Mater Chem B 2013 Mar 29;1(11):1519-1534. Epub 2013 Jan 29.

Center for Nano Science and Technology, Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.

Recent advances have led to the development of multifunctional bionanomaterials that can target a bone tumor and deliver therapeutic drugs or genes. Bionanomaterial-based bone cancer treatment offers hope for treating bone cancer and provides many exciting possibilities to enable important new therapeutic outcomes. Physicists, chemists, engineers, biologists, and clinicians will continue to address research questions at the level of fundamental biology and science to develop novel biomaterials and systems, particularly enabling cost-effective and large-scale production of multifunctional nanomaterial systems. This review provides a comprehensive reflection of the recent advancements in bionanomaterials for use in bone cancer treatment. The review examines in detail different bionanomaterials (hydroxyapatite nanocrystals and nanometals, nanoscale conjugated copolymer, selenium and liposome) that have been researched and developed over the last six years for bone tissue engineering. It also discusses an important area of research - the use of engineered bone scaffolds in cancer treatment. Recently, bone scaffolds have been identified as potential targets for metastatic spread as well as a means by which escape from tumor dormancy can be studied. This review also includes discussions of a highly potent new class of anticancer compounds, e.g., geminal bisphosphonates, that has been shown to have strong affinity towards various hydroxyapatite-based bone scaffolds with controlled adsorption and release for anticancer activity. Finally, perspectives on future directions in nanotechnology-enabled bone tumor treatment are presented.
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http://dx.doi.org/10.1039/c3tb00536dDOI Listing
March 2013

Graphene oxide-based hydrogels to make metal nanoparticle-containing reduced graphene oxide-based functional hybrid hydrogels.

ACS Appl Mater Interfaces 2012 Oct 1;4(10):5472-82. Epub 2012 Oct 1.

Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.

In this study, stable supramolecular hydrogels have been obtained from the assembly of graphene oxide (GO) in presence of polyamines including tris(aminoethyl)amine, spermine, and spermidine [biologically active molecule]. One of these hydrogels has been well characterized by various techniques including field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD) study, and Raman spectroscopy. TEM and AFM studies of one of these hydrogels have revealed the presence of a network structure of cross-linked nanosheets. This suggests the supramolecular assembly of GO in the presence of polyamines using the acid-base type electrostatic interaction. In presence of a mild reducing agent (vitamin C), one of these GO hydrogels has been transformed into a reduced graphene oxide (RGO)-based hydrogel by a simple in situ reduction of GO sheets within the hydrogel matrix. Moreover, noble metal nanoparticle containing RGO based hybrid hydrogels have been obtained using in situ and simultaneous co-reduction of GO and noble metal precursors within the GO gel matrix. The elegance of this method is in situ, "green chemical" and simultaneous reduction of GO and metal salts within the hydrogel matrix to form RGO-based hybrid gel and concomitant stabilization of metal nanoparticles (MNPs) within the gel system. The nascently formed MNPs are homogeneously and uniformly distributed on the surface of the RGO nanosheets within the hybrid gel. Interestingly, this MNP containing RGO-based hybrid hydrogel matrix acts as a potential catalyst for the reduction of aromatic nitro to amino group. The catalyst (hybrid gel matrix) can be separated easily after the reaction and reused several times.
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http://dx.doi.org/10.1021/am301373nDOI Listing
October 2012

Synthesis of gold nanoparticles in niosomes.

J Colloid Interface Sci 2012 Nov 16;386(1):9-15. Epub 2012 Jul 16.

Department of Chemistry, University of Kalyani, Kalyani, West Bengal, India.

This work outlines a novel method for the synthesis of stable gold nanoparticles within the spatially confined region of vesicles. For the first time, Span/cholesterol based niosomes have been used for nanoparticle synthesis. The restricted geometry within niosomes prevents nanoparticle aggregation. The results have important implications for controlled delivery of nanoparticles for therapeutic applications.
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http://dx.doi.org/10.1016/j.jcis.2012.06.073DOI Listing
November 2012

Advances in top-down and bottom-up surface nanofabrication: techniques, applications & future prospects.

Adv Colloid Interface Sci 2012 Jan 16;170(1-2):2-27. Epub 2011 Nov 16.

Center for Nano Science and Technology (NDnano), Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.

This review highlights the most significant advances of the nanofabrication techniques reported over the past decade with a particular focus on the approaches tailored towards the fabrication of functional nano-devices. The review is divided into two sections: top-down and bottom-up nanofabrication. Under the classification of top-down, special attention is given to technical reports that demonstrate multi-directional patterning capabilities less than or equal to 100 nm. These include recent advances in lithographic techniques, such as optical, electron beam, soft, nanoimprint, scanning probe, and block copolymer lithography. Bottom-up nanofabrication techniques--such as, atomic layer deposition, sol-gel nanofabrication, molecular self-assembly, vapor-phase deposition and DNA-scaffolding for nanoelectronics--are also discussed. Specifically, we describe advances in the fabrication of functional nanocomposites and graphene using chemical and physical vapor deposition. Our aim is to provide a comprehensive platform for prominent nanofabrication tools and techniques in order to facilitate the development of new or hybrid nanofabrication techniques leading to novel and efficient functional nanostructured devices.
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http://dx.doi.org/10.1016/j.cis.2011.11.001DOI Listing
January 2012

Graphene oxide-based supramolecular hydrogels for making nanohybrid systems with Au nanoparticles.

Langmuir 2012 Jan 23;28(2):1460-9. Epub 2011 Dec 23.

Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.

In the presence of a small amount of a proteinous amino acid (arginine/tryptophan/histidine) or a nucleoside (adenosine/guanosine/cytidine), graphene oxide (GO) forms supramolecular stable hydrogels. These hydrogels have been characterized by field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) analysis, Raman spectroscopy, and rheology. The morphology of the hydrogel reveals the presence of nanofibers and nanosheets. This suggests the supramolecular aggregation of GO in the presence of an amino acid/nucleoside. Rheological studies of arginine containing a GO-based hydrogel show a very high G' value (6.058 × 10(4) Pa), indicating the rigid, solid-like behavior of this gel. One of these hydrogels (GO-tryptophan) has been successfully utilized for the in situ synthesis and stabilization of Au nanoparticles (Au NPs) within the hydrogel matrix without the presence of any other external reducing and stabilizing agents to make Au NPs containing the GO-based nanohybrid material. The Au NPs containing the hybrid hydrogel has been characterized by using UV/vis spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). In this study, gold salt (Au(3+)) has been bioreduced by the tryptophan within the hydrogel. This is a facile "green chemical" method of preparing the GO-based nanohybrid material within the hydrogel matrix. The significance of this method is the in situ reduction of gold salt within the gel phase, and this helps to decorate the nascently formed Au NPs almost homogeneously and uniformly on the surface of the GO nanosheets within the gel matrix.
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http://dx.doi.org/10.1021/la203498jDOI Listing
January 2012

Design and synthesis of biomimetic multicomponent all-bone-minerals bionanocomposites.

Biomacromolecules 2010 Oct;11(10):2545-9

Center for Nanoscience and Technology (NDnano), Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, United States.

We report a simple and novel top-down method based on a drop-casting process for the controlled synthesis of all-bone-minerals biomimetic multicomponent bionanocomposites. Integration of micro- and nanoscale binary features into nanofibrous biocompatible polymer scaffold structures is successfully demonstrated. Compositional control of the constituents of the bionanocomposites resulted in uniform dispersion of hydroxyapatite nanospheres (~100-500 nm) among collagen nanofibers (~100 nm). The composites also present high calcium and oxygen contents and adequate phosphorus compositions comparable to the levels of bone tissues. Our preliminary results open up further possibilities to develop advanced tissue-engineered bionanocomposites for bone grafting.
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http://dx.doi.org/10.1021/bm1009359DOI Listing
October 2010

Molecularly ordered decanethiolate self-assembled monolayers on Au(111) from in situ cleaved decanethioacetate: an NMR and STM study of the efficacy of reagents for thioacetate cleavage.

Langmuir 2010 Aug;26(16):13221-6

Department of Chemistry and Biochemistry, 620 Parrington Oval, University of Oklahoma, Norman, Oklahoma 73019, USA.

The cleavage of decanethioacetate (C10SAc) has been studied by (1)H nuclear magnetic resonance (NMR) spectroscopy and scanning tunneling microscopy (STM) imaging of in situ prepared decanethiolate self-assembled monolayers (SAMs) on Au(111). Solutions of C10SAc (46 mM) and previously reported cleavage reagents (typically 58 mM) in CD(3)OD were monitored at 20 degrees C by NMR spectroscopy. Cleavage by ammonium hydroxide, propylamine, or hydrochloric acid was not complete within 48 h; cleavage by potassium carbonate was complete within 24 h and that by potassium hydroxide or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) within 2 h. Similar cleavage rates were observed for phenylthioacetate. The degree of molecular ordering determined by STM imaging increased with increasing extent of in situ cleavage by these same reagents (2.5 mM C10SAc and 2.5 mM reagent in ethanol for 1 h, then 16 h immersion of Au/mica). Less effective cleavage reagents did not cleave the C10SAc sufficiently to decanethiol (C10SH) and gave mostly disordered SAMs. In contrast, KOH or DBU completely cleaved the C10SAc to C10SH and led to well-ordered SAMs composed of (square root(3) x square root(3))R30 degrees domains that are indistinguishable from SAMs grown from C10SH. Monolayer formation from thioacetates in the absence of cleavage agents is likely due to thiol or disulfide impurity in the thioacetates. Eliminating disulfide by using Bu(3)P as a sacrificial reductant also helped to produce good molecular order in the SAM. The methods presented here allow routine growth of molecularly ordered alkanethiolate SAMs from thioacetates using reagents of ordinary purity under ambient, benchtop conditions.
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http://dx.doi.org/10.1021/la100103kDOI Listing
August 2010

Single metal nanoparticle spectroscopy: optical characterization of individual nanosystems for biomedical applications.

Nanoscale 2010 Sep 27;2(9):1560-72. Epub 2010 Jul 27.

Center for Nanoscience and Technology (NDnano), Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.

The last decade has witnessed the development of a variety of single nanoparticle spectroscopy methods. This has facilitated unprecedented growth of knowledge and understanding of fascinating optical properties of individual metal nanoparticles. This has opened up exciting possibilities of single nanoparticles for applications in many areas including advanced photonics, biomedical imaging and sensing. The field of single nanoparticles detection and characterization is still growing. This paper reviews recent advances in single nanoparticles spectroscopy using both near-field and far-field optics. It covers spectroscopy methods for extremely small (approximately 1 nm) to relatively large nanoparticles (approximately 200 nm) and their optical properties. Different optical techniques are described. Finally, a perspective on possible practical applications of single nanoparticle spectroscopy focusing on biomedical fields is given.
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http://dx.doi.org/10.1039/c0nr00133cDOI Listing
September 2010

Tailored polymer-metal fractal nanocomposites: an approach to highly active surface enhanced Raman scattering substrates.

Nanotechnology 2009 Aug 21;20(32):325705. Epub 2009 Jul 21.

Center for Semiconductor Physics in Nanostructures, Homer L Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA.

An important design approach for sensitive and robust surface enhanced Raman scattering (SERS) substrates is the use of metal nanoparticle aggregates with nanometer tailored interstitial distances between their surfaces, in order to confine the electromagnetic energy. The nanostructural instability of the aggregates to agglomeration due to their strong van der Waals force poses a challenge for the preparation of large-scale, reliable SERS substrates. We present a novel route for preparing stable and highly active SERS substrates using polymer-metal fractal nanocomposites. This methodology is based on the unique morphology of fractal nanocomposite structures formed just below the percolation threshold that consists of extremely narrow (approximately 0.8 nm) interstitial polymer junctions between the Ag nanoparticle aggregates along with the appropriate nanoscale (<100 nm) surface roughness. Such nanomorphology allows the formation of well-defined and large numbers of hot spots where the localization of electromagnetic energy can result in very large enhancement of the Raman signal. We applied a simple plasma etching process to remove the polymer structures that allowed the formation of Ag structures with very uniform and controllable inter-particle gaps that were proved to provide significant SERS enhancement of typical biological systems such as double-stranded deoxyribonucleic acid (dsDNA). These advanced nanocomposite films could be used for the development of large-scale spectroscopy-based sensors for direct detection and analysis of various biological and chemical samples.
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http://dx.doi.org/10.1088/0957-4484/20/32/325705DOI Listing
August 2009

Large-scale graphene production by RF-cCVD method.

Chem Commun (Camb) 2009 Jul 27(27):4061-3. Epub 2009 May 27.

Applied Science Department, University of Arkansas at Little Rock, AR 72204, USA.

In this work, we report a low-cost facile method for the production of few-layer graphene sheets in large quantities through radio-frequency chemical vapor deposition.
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http://dx.doi.org/10.1039/b906323dDOI Listing
July 2009

Strain-controlled growth of nanowires within thin-film cracks.

Nat Mater 2004 Jun 9;3(6):375-9. Epub 2004 May 9.

Lehrstuhl für Materialverbunde, Technische Fakultät der Universität Kiel, Germany.

There is continued interest in finding quicker and simpler ways to fabricate nanowires, even though research groups have been investigating possibilities for the past decade. There are two reasons for this interest: first, nanowires have unusual properties-for example, they show quantum-mechanical confinement effects, they have a very high surface-to-volume ratio, enabling them to be used as sensors, and they have the ability to connect to individual molecules. Second, no simple method has yet been found to fabricate nanowires over large areas in arbitrary material combinations. Here we describe an approach to the generation of well-defined nanowire network structures on almost any solid material, up to macroscopic sample sizes. We form the nanowires within cracks in a thin film. Such cracks have a number of properties that make them attractive as templates for nanowire formation: they are straight, scalable down to nanometre size, and can be aligned (by using microstructure to give crack alignment via strain). We demonstrate the production of nanowires with diameter <16 nm, both singly and as networks; we have also produced aligned patterns of nanowires, and nanowires with individual contacts.
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http://dx.doi.org/10.1038/nmat1128DOI Listing
June 2004