स्पर्शरेखा फ्लो Ultrafiltration: आकार और कोलाइडयन चांदी नैनोकणों का चयन एकाग्रता के लिए एक "ग्रीन" विधि
Summary
स्पर्शरेखा प्रवाह ultrafiltration (TFU) एक recirculation biosamples के वजन के आधार पर जुदाई के लिए इस्तेमाल किया विधि है. TFU आकार का चयन करें (1-20 एनएम व्यास) के लिए अनुकूलित किया गया था और अत्यधिक polydisperse नैनोकणों चांदी की एक बड़ी मात्रा (15.2 ग्राम मिलीलीटर की 4 एल ध्यान<sup> -1</sup> 8,539.9 ग्राम मिलीलीटर की नीचे 4 मिलीलीटर<sup> -1</sup>) न्यूनतम एकत्रीकरण के साथ.
Abstract
Nowadays, AgNPs are extensively used in the manufacture of consumer products,1 water disinfectants,2 therapeutics,1, 3 and biomedical devices4 due to their powerful antimicrobial properties.3-6 These nanoparticle applications are strongly influenced by the AgNP size and aggregation state. Many challenges exist in the controlled fabrication7 and size-based isolation4,8 of unfunctionalized, homogenous AgNPs that are free from chemically aggressive capping/stabilizing agents or organic solvents.7-13 Limitations emerge from the toxicity of reagents, high costs or reduced efficiency of the AgNP synthesis or isolation methods (e.g., centrifugation, size-dependent solubility, size-exclusion chromatography, etc.).10,14-18 To overcome this, we recently showed that TFU permits greater control over the size, concentration and aggregation state of Creighton AgNPs (300 ml of 15.3 μg ml-1 down to 10 ml of 198.7 μg ml-1) than conventional methods of isolation such as ultracentrifugation.19
TFU is a recirculation method commonly used for the weight-based isolation of proteins, viruses and cells.20,21 Briefly, the liquid sample is passed through a series of hollow fiber membranes with pore size ranging from 1,000 kD to 10 kD. Smaller suspended or dissolved constituents in the sample will pass through the porous barrier together with the solvent (filtrate), while the larger constituents are retained (retentate). TFU may be considered a “green” method as it neither damages the sample nor requires additional solvent to eliminate toxic excess reagents and byproducts. Furthermore, TFU may be applied to a large variety of nanoparticles as both hydrophobic and hydrophilic filters are available.
The two main objectives of this study were: 1) to illustrate the experimental aspects of the TFU approach through an invited video experience and 2) to demonstrate the feasibility of the TFU method for larger volumes of colloidal nanoparticles and smaller volumes of retentate. First, unfuctionalized AgNPs (4 L, 15.2 μg ml-1) were synthesized using the well-established Creighton method22,23 by the reduction of AgNO3 with NaBH4. AgNP polydispersity was then minimized via a 3-step TFU using a 50-nm filter (460 cm2) to remove AgNPs and AgNP-aggregates larger than 50 nm, followed by two 100-kD (200 cm2 and 20 cm2) filters to concentrate the AgNPs. Representative samples were characterized using transmission electron microscopy, UV-Vis absorption spectrophotometry, Raman spectroscopy, and inductively coupled plasma optical emission spectroscopy. The final retentate consisted of highly concentrated (4 ml, 8,539.9 μg ml-1) yet lowly aggregated and homogeneous AgNPs of 1-20 nm in diameter. This corresponds to a silver concentration yield of about 62%.
Protocol
Discussion
यूवी विज़ अवशोषण स्पेक्ट्रोफोटोमेट्री और कोलाइडयन AgNPs की रमन स्पेक्ट्रोस्कोपी
यह सर्वविदित है कि एक colloid के अवशोषण स्पेक्ट्रम में सतह plasmon अनुनाद चोटियों की संख्या AgNPs बढ़ जाती है की समरूपता के ?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
इंजीनियरिंग और नेता कंसोर्टियम कार्यक्रम में NUE के माध्यम से राष्ट्रीय विज्ञान फाउंडेशन से अनुदान कृतज्ञता से स्वीकार किया है.
Materials
| Silver nitrate (AgNO3) | Acros Organics Inc. | CAS: 7761-88-8 | |
| Sodium borohydride (NaBH4) | Acros Organics Inc. | CAS: 16940-66-2 | |
| Nitric acid (HNO3, Optima) | Fisher Scientific Inc. | A467-1 | Trace metal grade for ICP analysis |
| 10,000 μg ml-1 silver standard, EnviroConcentrate | Ultra Scientific | US-IAA-047 | |
| KrosFlo Research IIi Tangential Flow Filtration System | Spectrum Laboratories Inc. | SYR2-U20-01N | |
| 0.05 μm PS (0.5 mm) 460 cm2 | Spectrum Laboratories Inc. | X30S-900-02N | |
| Midi 100 kD PS 200 cm2 | Spectrum Laboratories Inc. | X3-100S-901-02N | |
| Micro100 kD PS 20 cm2 | Spectrum Laboratories Inc. | X1AB-300-10N | |
| MasterFlex C-Flex tubing L/S Size 17 | Cole-Palmer Instrument Co. | 06424-17 | |
| MasterFlex C-Flex tubing L/S Size 14 | Cole-Palmer Instrument Co. | 06424-14 | |
| Cary 50 UV-VIS-NIR spectrophotometer | Varian Inc. | ||
| LabRam HR 800 system | Horiba Jobin Yvon Inc. | ||
| Varian 710ES ICP-OES | Varian Inc. |
Table 1. Specific reagents and equipment.
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