This study aims to assess the effects of Ag particles synthesised by a chemical (Ag 20, 200 nm) and biological method (Ag 23, 27 nm) in aquatic organisms: the bacterium Vibrio fischeri, the alga Desmodesmus subspicatus and the crustacean Daphnia magna. Ag particles exerted toxic effects in all organisms studied with Ag particles 23 nm being the most potent. Although soluble Ag was released in all media, the differences between the tested Ag particles still cannot be explained solely based on soluble Ag. NanoSIMS analysis performed with D. magna showed that apart from their localisation in the gut lumen, Ag 200 nm and Ag NPs 23 nm seemed to pass through the epithelial barrier as well. Ag NPs 23 nm localised in specific areas seemed to be within the ovaries. This study strengthens the argument that size, method of synthesis as well as surface chemistry may affect the uptake and toxic effects of Ag NPs.
One of the biggest obstacles for the development of HIV vaccines is how to sufficiently trigger crucial anti-HIV immunities via a safe manner. We herein integrated surface modification-dependent immunostimulation against HIV vaccine and shape-dependent biosafety and designed a safe noncarrier adjuvant based on silver nanorods coated by both polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG). Such silver nanorods can significantly elevate crucial immunities of HIV vaccine and overcome the toxicity, which is a big problem for other existing adjuvants. This study thus provided a principle for designing a safe and high-efficacy material for an adjuvant and allow researchers to really have a safe and effective prophylaxis against HIV. We expect this material approach to be applicable to other types of vaccines, whether they are preventative or therapeutic.
Generally, limited research is extended in studying stability and applicational properties of silver nanoparticles (Ag NPs) synthesized by adopting ‘green chemistry’ protocol. In this work, we report on the synthesis of stable Ag NPs using plant-derived materials such as leaf extract of Neem (Azadirachta indica) and biopolymer pectin from apple peel. In addition, the applicational properties of Ag NPs such as surface-enhanced Raman scattering (SERS) and antibacterial efficiencies were also investigated. As-synthesized nanoparticles (NPs) were characterized using various instrumentation techniques. Both the plant materials (leaf extract and biopolymer) favored the synthesis of well-defined NPs capped with biomaterials. The NPs were spherical in shape with an average particle size between 14-27 nm. These bio-NPs exhibited colloidal stability in most of the suspended solutions such as water, electrolyte solutions (NaCl; NaNO3), biological solution (bovine serum albumin), and in different pH solutions (pH 7; 9) for a reasonable time period of 120 hrs. Both the bio-NPs were observed to be SERS active through displaying intrinsic SERS signals of the Raman probe molecule (Nile blue A). The NPs were effective against the Escherichia coli bacterium when tested in nutrient broth and agar medium. Scanning and high-resolution transmission electron microscopy (SEM and HRTEM) images confirmed cellular membrane damage of nanoparticle treated E. coli cells. These environmental friendly template Ag NPs can be used as an antimicrobial agent and also for SERS based analytical applications.
Aggregation-induced emission (AIE) produce strong, stable fluorescence upon aggregation, thus it is pushing a new frontier in bio-detection, cell imaging and other biomedical applications. In this review, we summarize the recent developments of AIEgens about design strategy, bio-detection, cell imaging, tumor imaging, vascular imaging and image-guided tumor therapy. We especially highlight a section on the microfluidic approach to synthesize AIE nanoparticles (NPs) and current challenges and promising prospects of AIE NPs.
Targeted delivery of therapeutic molecules using nanomaterials is desired to elicit specific responses toward diseases. Such an integrated synthesis of functional material using a microfluidic approach is a great challenge. Functional metal organic frameworks (MOFs) with unique structural diversity possess a complicated synthesis procedure thereby requiring a modest, straightforward approach to synthesize sizecontrollable MOFs. Here, we develop an integrated microfluidic chip to synthesize the aptamer-modified biozeolitic imidazolate framework (BioZIF-8) to target the lymph node and tumor. The first stage of the microfluidic chip forms the ZIF-8 encapsulating biomolecules (bovine serum albumin, small interfering ribonucleic acid, and doxorubicin). The second stage modifies the surface of BioZIF-8 with the aptamer. Our approach reduces the overall synthesis time (∼3 mg/10 min against 15 h for the conventional two-step method) and encapsulates a higher number of biomolecules. The microfluidic approach realizes the rapid and fine-tuned synthesis of functional MOFs integrated into one-step.
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