यहाँ हम जैविक शर्तों के तहत और तरल मीडिया में उपन्यास, उच्च पहलू अनुपात biocomposites के संश्लेषण के लिए एक प्रोटोकॉल उपस्थित थे। biocomposites क्रमशः, व्यास और लंबाई में माइक्रोमीटर नैनोमीटर से पैमाने। Cystine के साथ संयुक्त कॉपर नैनोकणों (CNPs) और तांबा सल्फेट संश्लेषण के लिए प्रमुख घटक हैं।
इस प्रोटोकॉल के लक्ष्य के उच्च पहलू अनुपात संरचनाओं के साथ दो उपन्यास biocomposites के संश्लेषण का वर्णन करने के लिए है। biocomposites तांबा नैनोकणों (CNPs) या धातु घटक योगदान तांबा सल्फेट के साथ या तो, तांबा और cystine से मिलकर बनता है। संश्लेषण जैविक शर्तों (37 डिग्री सेल्सियस) और 24 घंटे के बाद आत्म इकट्ठे कंपोजिट फार्म के नीचे तरल में किया जाता है। गठन के बाद, इन कंपोजिट दोनों तरल मीडिया में और एक सूखे के रूप में अत्यधिक स्थिर रहे हैं। कंपोजिट लंबाई में सीमा सूक्ष्म करने के लिए नैनो से पैमाने पर, और कुछ माइक्रोन से व्यास में 25 एनएम के लिए। ऊर्जा फैलानेवाला एक्स-रे स्पेक्ट्रोस्कोपी (EDX) के साथ क्षेत्र उत्सर्जन स्कैनिंग इलेक्ट्रॉन माइक्रोस्कोपी यह इस प्रकार अंतिम nanocomposites में सल्फर के स्रोत के रूप में cystine, पुष्टि शुरू कर CNP सामग्री से अनुपस्थित था, जबकि सल्फर, एनपी व्युत्पन्न रैखिक संरचनाओं में मौजूद था कि प्रदर्शन । इन रैखिक नैनो और सूक्ष्म कंपोजिट के संश्लेषण, एसटीआर की लंबाई की एक विविध रेंज के दौरानuctures संश्लेषण पोत में बनाई है। संश्लेषण के बाद तरल मिश्रण के sonication sonication के क्षेत्र की वृद्धि हुई समय के साथ औसत लंबाई ह्रासमान द्वारा संरचनाओं का औसत आकार को नियंत्रित करने में सहायता करने के लिए प्रदर्शन किया गया। का गठन संरचनाओं अत्यधिक agglomerate नहीं है, स्थिर, और तरल चरण में बनते हैं कर रहे हैं, centrifugation के भी ध्यान दे और गठन कंपोजिट को अलग करने में सहायता करने के लिए इस्तेमाल किया जा सकता है।
Copper is a highly reactive metal that in the biological world is essential in some enzyme functions 1,2, but in higher concentrations is potently toxic including in the nanoparticulate form 3,4. Concern over copper toxicity has become more relevant as CNPs and other copper-based nanomaterials are utilized, due to the increased surface area/mass for nanostructures. Thus, even a small mass of copper, in nanoparticle form, could cause local toxicity due to its ability to penetrate the cell and be broken down into reactive forms. Some biological species can complex with and chelate metal ions, and even incorporate them into biological structures as has been described in marine mussels 5. In studying the potential toxic effects of nanomaterials 4, it was discovered that over time, and under biological conditions used for typical cell culturing (37 °C and 5% CO2), stable copper biocomposites could be formed with a high-aspect ratio (linear) structure.
By a process of elimination, the initial discovery of these linear biocomposites, which occurred in complete cell culture media, was simplified to a defined protocol of essential elements needed for the biocomposites to self-assemble. Self-assembly of two types of highly linear biocomposites was discovered to be possible with two starting metal components: 1) CNPs and 2) copper sulfate, with the common biological component being cystine. Although more complex, so called “urchin” and “nanoflower” type copper-containing structures with nanoscale and microscale features have been previously reported, these were produced under non-biological conditions, such as temperatures of 100 °C or greater 6-8. To our knowledge, synthesis of individual, linear copper-containing nanostructures that are scalable in liquid phase under biological conditions has not been previously described.
One of the starting materials utilized for synthesis of nanocomposites, namely CNPs, has been reported previously to be very toxic to cells 4. It has recently been reported that after the nanocomposites are formed, these structures are less toxic on a per mass basis than the starting NPs 9. Thus, the synthesis described here may be derived from a biological and biochemical reaction that has utility in stabilizing reactive copper species, both in the sense of transforming the NP form into larger structures and in producing composites less toxic to cells.
In contrast to many other nanomaterial forms which are known to aggregate or clump upon interaction with biological liquid media 10,11, once formed, the highly linear composites described here avoid aggregation, possibly due to a redistribution of charge which has been previously reported 9. As detailed in the current work, this avoidance of aggregation is convenient for the purposes of working with the structures once formed for at least 3 reasons: 1) composite structures once formed may be concentrated using centrifugation and then easily dispersed again using vortex mixing; 2) formed structures can be decreased in average size by sonication for different periods of time; and 3) the formed linear structures may provide an additional tool for avoiding the recently described “coffee ring effect” 12 and thus provide a dopant for creating more evenly distributed coatings of materials, especially those containing spherical particulates.
CNPs सहित nanomaterials के संभावित विषाक्त प्रभाव का मूल्यांकन है, यह लंबे समय से अधिक, CNPs एक बड़ा, एकत्रित प्रपत्र को शुरू में एक अधिक बिखरे कण वितरण (चित्रा 2) से बदल रहे थे कि मनाया गया। कुछ मामलों में, जैविक श?…
The authors have nothing to disclose.
The authors would like to acknowledge the technical assistance of Alfred Gunasekaran in electron microscopy studies at the Institute of Micromanufacturing at Louisiana Tech University, and Dr. Jim McNamara for assistance with additional microscopy studies. The work described was supported in part by Louisiana board of Regents PKSFI Contract No. LEQSF (2007-12)-ENH-PKSFI-PRS-04 and the James E. Wyche III Endowed Professorship from Louisiana Tech University (to M.D.).
Mini Vortexer | VWR (https://us.vwr.com) | 58816-121 | |
CO2 Incubator Model # 2425-2 | VWR (https://us.vwr.com) | Contact vendor | Current model calalog # 98000-360 |
Eppendorf Centrifuge (Refrigerated Microcentrifuge) | Labnet (http://labnetinternational.com/) | C2500-R | Model Prism R |
Cell Culture Centrifuge Model Z323K | Labnet (http://labnetinternational.com/) | Contact vendor | Current model Z206A catalog # C0206-A |
Sonicator (Ultrasonic Cleaner) | Branson Ultrasonics Corporation (http://www.bransonic.com/) | 1510R-MTH | |
Balance | Sartorius (http://dataweigh.com) | Model CP225D similar model CPA225D | |
Olympus IX51 Inverted Light Microscope | Olympus (http://olympusamerica.com | Contact vendor | |
Olympus DP71 microscope digital camera | Olympus (http://olympusamerica.com | Contact vendor | |
external power supply unit- white light for Olympus microscope | Olympus (http://olympusamerica.com | TH4-100 | |
10x, 20, and 40x microscope objectives | Olympus (http://olympusamerica.com | Contact vendor | |
Scanning Electron Microscope | Hitachi (http://hitachi-hitec.com/global/em/sem/sem_index.html) | model S-4800 | |
Transmission Electron Microscope | Zeiss (http://zeiss.com/microscopy/en_de/products.html) | model Libra 120 | |
Table Top Work Station Unidirectional Flow Clean Bench | Envirco (http://envirco-hvac.com) | model PNG62675 | Used for sterile cell culture technique |