Optically active organic and inorganic nanomaterials for biological imaging applications: A review

Recent advancements in the field of nanotechnology have enabled targeted delivery of drug agents in vivo with minimal side effects. The use of nanoparticles for bio-imaging has revolutionized the field of nanomedicine by enabling non-invasive targeting and selective delivery of active drug moieties in vivo. Various inorganic nanomaterials like mesoporous silica nanoparticles, gold nanoparticles, magnetite nanoparticles graphene-based nanomaterials etc., have been created for multimodal therapies with varied multi-imaging modalities. These nanomaterials enable us to overcome the disadvantages of conventional imaging contrast agents (organic dyes) such as lack of stability in vitro and in vivo, high reactivity, low-quantum yield and poor photo stability. Inorganic nanomaterials can be easily fabricated, functionalised and modified as per requirements. Recently, advancements in synthesis techniques, such as the ability to generate molecules and construct supramolecular structures for specific functionalities, have boosted the usage of engineered nanomaterials. Their intrinsic physicochemical properties are unique and they possess excellent biocompatibility. Inorganic nanomaterial research has developed as the most actively booming research fields in biotechnology and biomedicine. Inorganic nanomaterials like gold nanoparticles, magnetic nanoparticles, mesoporous silica nanoparticles, graphene-based nanomaterials and quantum dots have shown excellent use in bioimaging, targeted drug delivery and cancer therapies. Biocompatibility of nanomaterials is an important aspect for the evolution of nanomaterials in the bench to bedside transition. The conduction of thorough and meticulous study for safety and efficacy in well-designed clinical trials is absolutely necessary to determine the functional and structural relationship between the engineered nanomaterial and its toxicity. In this article an attempt is made to throw some light on the current scenario and developments made in the field of nanomaterials in bioimaging.

Nanomaterials in anticancer applications and their mechanism of action - A review

The current challenges in cancer treatment using conventional therapies have made the emergence of nanotechnology with more advancements. The exponential growth of nanoscience has drawn to develop nanomaterials (NMs) with therapeutic activities. NMs have enormous potential in cancer treatment by altering the drug toxicity profile. Nanoparticles (NPs) with enhanced surface characteristics can diffuse more easily inside tumor cells, thus delivering an optimal concentration of drugs at tumor site while reducing the toxicity. Cancer cells can be targeted with greater affinity by utilizing NMs with tumor specific constituents. Furthermore, it bypasses the bottlenecks of indiscriminate biodistribution of the antitumor agent and high administration dosage. Here, we focus on the recent advances on the use of various nanomaterials for cancer treatment, including targeting cancer cell surfaces, tumor microenvironment (TME), organelles, and their mechanism of action. The paradigm shift in cancer management is achieved through the implementation of anticancer drug delivery using nano routes.

The impact of engineered nanomaterials on the environment: Release mechanism, toxicity, transformation, and remediation

The presence and longevity of nanomaterials in the ecosystem, as well as their properties, account for environmental toxicity. When nanomaterials in terrestrial and aquatic systems are exposed to the prevailing environmental conditions, they undergo various transformations such as dissociation, dissolution, and aggregation, which affects the food chain. The toxicity of nanomaterials is influenced by a variety of factors, including environmental factors and its physico-chemical characteristics. Bioaccumulation, biotransformation, and biomagnification are the mechanisms that have been identified for determining the fate of nanomaterials. The route taken by nanomaterials to reach living cells provides us with information about their toxicity profile. This review discusses the recent advances in the transport, transformation, and fate of nanomaterials after they are released into the environment. The review also discusses how nanoparticles affect lower trophic organisms through direct contact, the impact of nanoparticles on higher trophic organisms, and the possible options for remediation.

Utilization of Carica papaya latex on coating of SPIONs for dye removal and drug delivery

Latex, a milky substance found in a variety of plants which is a natural source of biologically active compounds. In this study, Latex was collected from raw Carica papaya and was characterized using UV-Vis, FTIR and GC-MS analyses. Super Paramagnetic Iron Oxide Nanoparticles (SPIONs) were synthesized, coated with C. papaya latex (PL-Sp) and characterized using UV-Vis, FT-IR, SEM-EDX, XRD, VSM and Zeta potential analyses. SPIONs and latex coated SPIONs (PL-Sp) were used in batch adsorption study for effective removal of Methylene blue (MB) dye, where (PL-Sp) removed MB dye effectively. Further the PL-Sp was used to produce a nanoconjugate loaded with curcumin and it was characterized using UV-Vis spectrophotometer, FT-IR, SEM-EDX, XRD, VSM and Zeta potential. It showed a sustained drug release pattern and also found to have good antibacterial and anticancer activity.

Effect of biosynthesized gold nanoparticles by Sargassum swartzii in alloxan induced diabetic rats

Biosynthesis of gold nanoparticles (AuNPs) using Sargassum swartzii and its anti-diabetic effect were studied using male wistar Albino rats. Formation of AuNPs were confirmed by UV-vis spectroscopy, Fourier transformed infrared (FTIR) spectroscopy, High-Resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD). Fasting blood glucose levels, serum insulin, hemoglobin and glycosylated hemoglobin levels in diabetic treated rats with AuNPs were significantly decreased compared to the control group. The results of the blood glucose level and serum insulin levels indicated that AuNPs could significantly improve the insulin resistance and glucose level in diabetic rats. AuNPs also shows reduction in anti-inflammation, tumor necrosis factor-alpha, interleukin-6 and high-sensitive C-reactive protein in diabetic rats. The data showed that AuNPs synthesized using S. swartzii exerted antidiabetic effect, accordingly improve pancreas, liver and kidney damage caused by alloxan induced diabetic rats.

Size controlled biogenic silver nanoparticles as antibacterial agent against isolates from HIV infected patients

Silver nanoparticles (AgNPs) are synthesized using biological sources due to its high specificity in biomedical applications. Herein, we report the size and shape controlled synthesis of AgNPs using the aqueous extract of blue green alga, Spirulina platensis. Size, shape and elemental composition of AgNPs were characterized using UV-vis spectroscopy, Fluorescence spectroscopy, FT-IR (Fourier Transform-Infrared Spectroscopy), FT-RS (Fourier Transform-Raman Spectroscopy), SEM-EDAX (Scanning Electron Microscopy-Energy Dispersive X-ray analysis) and HR-TEM (High Resolution Transmission Electron Microscopy). AgNPs were stable, well defined and monodispersed (spherical) with an average size of 6 nm. The synthesized AgNPs were tested for its antibacterial potency against isolates obtained from HIV patients.

Biosynthesis of Gold Nanoparticles and Identification of Capping Agent Using Gas Chromatography-Mass Spectrometry and Matrix Assisted Laser Desorption Ionization-Mass Spectrometry

In the present study, gold nanoparticles (AuNPs) were synthesized using leaf extract of Syzygium jambolanum and capping agent has been explored. The synthesized AuNPs have been characterized using UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HRTEM) and atomic force microscopic (AFM) analysis. The AuNPs show intense surface plasmon resonance (SPR) band at 528 nm and were found to be spherical and hexagonal in shape with particle size ranging from 20-30 nm. Transmission electron microscopy and atomic force microscopy were used to analyze the surface morphology of synthesized AuNPs. The capping ligand has been evaluated using matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) and gas chromatography-mass spectrometry (GC-MS) analysis.

Biosynthesis of gold nanoparticles using Sargassum swartzii and its cytotoxicity effect on HeLa cells

In this investigation, biological synthesis of gold nanoparticles (AuNPs) using Sargassum swartzii and its cytotoxicity against human cervical carcinoma (HeLa) cells is reported. The biological synthesis involved the reduction of chloroauric acid led to the formation of AuNPs within 5min at 60°C and the formation of AuNPs was confirmed using UV-vis spectrophotometer. The AuNPs were stable; spherical in shape with well-defined dimensions, and the average size of the particle is 35nm. A zeta potential value of -27.6mV revealed synthesized AuNPs were highly stable. The synthesized AuNPs exhibited a dose-dependent cytotoxicity against human cervical carcinoma (HeLa) cells. Furthermore, induction of apoptosis was measured by DAPI (4',6-Diamidino-2-phenylindole dihydrochloride) staining.

Effect of biologically synthesized gold nanoparticles on alloxan-induced diabetic rats-an in vivo approach

Development of novel antidiabetic agents using various organic compounds and biomolecules has been in practice for a long time. Recently, nanomaterials are also being used in antidiabetic studies for their unique properties such as small size, biocompatibility and ability to penetrate cell membrane for carrying drugs. Herein, in vivo antidiabetic activity of gold nanoparticles (AuNPs) synthesized using the antidiabetic potent plant Gymnema sylvestre R. Br on wistar albino rats has been evaluated. The formation of AuNPs and their morphology were confirmed using spectroscopic and microscopic analyses, respectively. The treatment of AuNPs has shown significant reduction in blood glucose level on diabetic rats. AuNPs were also tested for its anti-inflammatory effect by estimating the serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and high-sensitive C-reactive protein (CRP).

Facile synthesis of silver chloride nanoparticles using marine alga and its antibacterial efficacy

Exploitation of advancements in antimicrobial agent synthesis assisted by nanomaterials has received considerable attention in the recent years. Based on this, an eco-friendly approach for the synthesis of silver chloride nanoparticles (AgClNPs) using aqueous extract of Sargassum plagiophyllum is emphasized. UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FESEM) were used to characterize the formation of AgClNPs. X-ray diffraction (XRD) patterns clearly illustrate the presence of AgClNPs. The synthesized AgClNPs were tested for its antibacterial activity and it was found to cause considerable amount of deterioration to bacterial cells, when examined using electron microscope and cell viability analysis.

Sargassum myriocystum mediated biosynthesis of gold nanoparticles

Functionalized metal nanoparticles are unique in nature and are being developed for its specificity in drug targeting. In the present study, aqueous extract of Sargassum myriocystum is used for the biosynthesis of gold nanoparticles (AuNPs) by the reduction of chloroauric acid. The formation of nanoparticles reaction was complete within 15 min at 76 °C. The size, shape and elemental analysis of AuNPs were carried out using UV-visible absorption spectroscopy, FT-IR, TEM, SEM-EDAX, and XRD analysis. The newly formed AuNPs are stable, well-defined, polydispersed (triangular and spherical) and crystalline with an average size of 15 nm. The biomolecule involved in stabilizing AuNPs was identified using GC-MS.