Materials Science Forum Vol. 754

Abstract: Carbohydrates are attractive molecules for drug discovery because sugars are involved in many intricate human diseases including cancer and infectious diseases. Potential therapeutic and diagnostic benefits of sugar-based drugs, however, are offset by the poor pharmacologic properties of these molecules that include speedy serum clearance, poor cellular uptake, and the relatively high concentrations required for efficacy. To address these issues, carbohydrates are functionalized with nanocarrier as similar to peptides, proteins and DNA. Considering the vast relevance of Inorganic nanoparticles as promising candidates for electronic, optical, magnetic and biomedical applications, several metals linked glyconanoparticles (GNPs) are synthesized and applied for biomedical application. This article will elaborately discuss about the progress in the development of metallic GNPs for various biological applications as drug candidates and detection agents.

Abstract: Nanomedicine is a relatively new field of science and technology. By interacting with biomolecules, therefore at nanoscale, nanotechnology opens up a vast field of research and application. Current and potential applications of nanotechnology in medicine range from research involving diagnostic devices, drug delivery vehicles to enhanced gene therapy and tissue engineering procedures. Its advantage over conventional medicine lies on its size. Operating at nanoscale allows to exploit physical properties different from those observed at microscale such as the volume/surface ratio. This allows drugs of nanosize be used in lower concentration and has an earlier onset of therapeutic action. It also provides materials for controlled drug delivery by directing carriers to a specific location. Inorganic nanomedicine is likely to remain one of the most prolific fields of nanomedicine, which refers to the use of inorganic or hybrid (inorganic-inorganic or inorganic-organic) nanomaterials (INMs) and nanoparticles (INPs) to achieve innovative medical advances for body parts implantation, drug and gene discovery and delivery, discovery of biomarkers, and molecular diagnostics. Among the most promising INMs being developed are metal, silica, dendrimers, organic-inorganic hybrids, ceramics (e.g. ZrO₂, TiO₂, Al₂O₃, etc.) and bioinorganic hybrids. Metal NP contrast agents enhance magnetic resonance imaging and ultrasound results in biomedical applications of in vivo imaging. Hollow and porous INMs have been exploited for drug and gene delivery, diagnostic imaging, and photothermal therapy. Biomolecular inorganic nanohybrids and nanostructured biomaterials have been exploited for targeted imaging and therapy, drug and gene delivery, and regenerative medicine. Potential uses for fluorescent quantum dots (QDs) include cell labeling, biosensing, in vivo imaging, bimodal magnetic-luminescent imaging, and diagnostics. Biocompatible QD conjugates have been used successfully for sentinel lymph node mapping, tumor targeting, tumor angiogenesis imaging, and metastasis cell tracking. This article outlines present developments and future prospects for the use of Ti-based NPs and NMs in experimental in vivo and in vitro studies and in engineering nanodevices and biosensors for clinical and investigative use in diagnosis and therapy in diverse fields of medical sciences, such as oncology, infection control, orthopedics, dentistry, dermatology, genetics, cardiology, ophthalmology, etc. Toxicological considerations of these INPs and INMs are also discussed.

Abstract: Metal oxides form part of inorganic medicines called Bhasmas, which has been used in a non-allopathic medicine system practiced in India called Ayurveda. Bhasmas may be classified under the nanomedicines of ancient India. The traditional preparation methods involve time consuming and complicated preparation procedures. This paper highlights a novel ultrasound assisted technique called sonochemical synthesis of transition metal oxides in a facile, faster, inherently safer and environmentally benign (green chemistry) way which could be considered to be used for the synthesis of metal oxides such as copper oxide which form part of the copper based Ayurvedic nanomedicine called tamra bhasma, which is copper in its oxide form and used therapeutically as a source of copper. The synthesis procedure outlined here could be considered for the preparation of other types of Bhasmas also.

Abstract: There is a growing interest in the use of green resources for nanoparticle (NP) synthesis. Natural polymer, Chitosan (CH) has been employed as templates for the preparation of metal oxide NPs. They modify the surface characteristics of the nanometal oxides generated. In the presence of template CH, the spatial separation of the particles, enable the synthesis of highly crystalline, mono-dispersed particles of < 100 nm. The properties of metal oxides can be improved by combining with CH and the product can be employed for different applications. CH along with metal oxide NPs has recently been utilized as a stabilizing agent due to its excellent film-forming ability, mechanical strength, biocompatibility, non-toxicity, high permeability towards water, susceptibility to chemical modification and cost-effectiveness. Metal oxide NPs-CH based hybrid composites have attracted much interest for the development of desired biosensors, MRI agents, buffers, antibacterial agents etc.

Abstract: Nanoparticles are the cutting edge of the rapidly developing field of nanotechnology, which enables visualization and manipulation of matter down to the atomic level. Their unique size to volume ratio, shape and thermal stability make these materials superior, and rapidly usable in various bio-medical applications. This brief review summarize the recent advances in the field of applied nanomaterials with an emphasis in designing nanoscale devices with pre-defined structure, and their potential applications in the field of biology and medicine.

Abstract: Gadolinium complex of 2-aminothiophenol conjugated DTPA (DTPA=diethylenetriamine N,N,N',N",N" pentacetic acid) bis (amide) has been synthesized and characterized by various analytical techniques such as elemental analysis (EA), NMR, FAB-MS, IR, UV etc. This thiolated GdL (where L is a conjugate of DTPA and 2-aminothiophenol) has been anchored on the gold nanoparticles surfaces through thiols functionalites. These gold nanoparticles (AuNPs) have been synthesized by the reduction of gold tetrachloride (HAuCl₄) using sodium citrate as reducing agent. The surface functionalization has been performed by the replacement of citrate coat on the gold nanoparticle surface with thiolated Gd-chelate, Au@GdL. The Au@GdL has been analyzed by XRD, transmission electron microscope (HRTEM), UV, ICP-MS etc. The average size of nanoparticles is about 22 nm with a uniform spherical shape. A very high number of GdL has been loaded on nanoparticle surface reaching up to 7.9x10³ of Gd (III)- chelates per nanoparticle and they demonstrate very high r₁ relaxivity and the r₁ relaxivity per [G is much higher than the Gd (III)-chelate alone. The bimodality has also been tested using in-vitro x-ray computed tomography (x-ray CT). These nanoparticles (GNPs) are very stable and homogeneously dispersed in aqueous solution.

Abstract: A brief review on the antimicrobial application of Ag nanoparticles (AgNP) is presented. Ag in nanoform is considered less toxic than Ag⁺ ions and hence, a considerable amount of research has been carried out on the antibacterial, antifungal and antiviral activities of Ag nanoparticles. Poly (vinyl alcohol) (PVA) stabilized AgNPs provide overwhelming evidence on their potency against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumonia etc. A recent study using biostabilized AgNPs have shown their efficacies against a vast range of bacteria. The antibacterial activity of AgNPs has also resulted in the development of wound dressings and medical devices. Some results on the antifungal activities exhibited by them are also highlighted.

Abstract: Although surface-enhanced Raman scattering (SERS) has crossed its infancy long ago, it is yet to persuade different challenges to make it available in day-to-day applications. SERS is being criticized mainly due to the quality of the SERS analyses that uses substrates to get the giant enhancement for respective Raman signal of the target molecule. Hence, understanding the phenomena behind substrates, cost-effective development and optimization of such substrates for routine analytical purposes and utilization of modern modalities to get the insights out has become a very wide-spreading and interesting area of research. In this piece of work, several key terminologies related to SERS have been presented in brief. Since SERS is a localized surface plasmon resonance (LSPR) mediated signal-enhancing phenomena, it is indispensable to understand the correlation between LSPR excitations originated from substrate and SERS signal originated from molecules. A wide range of SERS-active substrates including scattered nanoaggregates, anisotropic assembly, two-dimensional nanostructure, multi-layered nanostructure of gold nanoparticles and colloidal approach have been used to interpret such correlation between LSPR excitations and SERS characteristics. Few exemplary applications of SERS have been also mentioned followed by typical simulative work how nanoobject behaves at different excitations and polarizations.