LK는 국립 과학 재단 대학원 연구 친교 프로그램 (DGE-1445197)와 밴 더 빌 트 대학 화학 부서에서 자금에 대 한 감사. LK와 EH 오시리스 가장 악기 (NSF EPS 1004083)에 대 한 자금 지원을 감사 하 고 싶습니다.

1. Synthesis and Characterization of AVL
<ol>
	<li>Place a magnetic stir bar inside a 2 neck 500 mL round bottom flask (Flask 1) and seal with an appropriate sized rubber septum and steel wire. Flame dry the flask to remove moisture by purging with nitrogen gas connected through an inlet needle and open outlet needle in the septum, while using a butane flame torch to gently heat the outside of the flask by moving the flame along the surface.
	<ol>
		<li>Continue heating the entire flask by running the flame across the surface until moisture clouding the inside of the flask is not seen. Remove the flame and let the flask cool to room temperature while continuing the nitrogen flow throughout the reaction.</li>
	</ol>
	</li>
	<li>Add 156.25 mL anhydrous tetrahydrofuran (THF) via a 30 mL syringe to Flask 1. Cool Flask 1 to -78 &#176;C with a dry ice/acetone bath. Monitor the temperature with a thermometer throughout the reaction and add dry ice as needed to maintain -78 &#176;C. Begin stirring the magnetic stir bar using a magnetic stir plate to create a gentle vortex.</li>
	<li>Add N,N-diisopropylethylamine (DIPA) (3.30 mL, 2.3 x 10-2 mol) via a 5 mL syringe, followed by the dropwise addition of 2.5 M n-Butyllithium (9.34 mL, 2.3 x 10-2 mol) via a 10 mL glass syringe equipped with a needle locking mechanism and metal needle to Flask 1. Continue to stir using a magnetic stir plate for 15 min at -78 &#176;C.</li>
	<li>Flame dry (as described in step 1.1) and purge with argon gas (as described in step 1.1 with nitrogen gas) a 100 mL round bottom flask (Flask 2). Remove the argon gas inlet and outlet at the same time once the flask is cool enough to touch. Add 56 mL anhydrous THF via a 30 mL syringe and &#948;-valerolactone (VL) (1.97 mL, 2.1 x 10-2 mol) via a 5 mL syringe.</li>
	<li>Add the solution in Flask 2 to Flask 1 via a small cannula dropwise over 45 min while continuously stirring via a magnetic stir bar. Once Flask 2 is empty, remove the cannula and allow Flask 1 to continue stirring for 15 min at -78 &#176;C.</li>
	<li>Flame dry (as described in step 1.1) and purge with argon gas (as described in step 1.1 with nitrogen gas) a 25 mL round bottom flask (Flask 3). Remove the argon gas inlet and outlet at the same time once the flask is cool enough to touch, to maintain positive pressure inside the flask. Add ally bromide (2.02 mL, 2.3 x 10-2 mol) and hexamethyphosphoramide (HMPA) (4.43 mL, 2.5 x 10-2 mol) each via a 5 mL syringe.</li>
	<li>Add Flask 3 to Flask 1 via a small cannula dropwise. Once Flask 3 is empty, remove the cannula.
	<ol>
		<li>Remove as much dry ice and cold acetone as possible from the dry ice/acetone bath in which Flask 1 is submerged using a scoop and plastic cup. Replace with room temperature acetone to raise the bath to -40 &#176;C and allow Flask 1 to continue stirring for 2 h while monitoring the temperature. If the temperature increases above -40 &#176;C, add a few pieces of dry ice to cool the acetone.</li>
		<li>Warm to -10 &#176;C by removing the cold acetone and dry ice and replace with room temperature acetone.</li>
	</ol>
	</li>
	<li>Remove the septum from Flask 1 and quench the reaction with a 150 mL saturated ammonium chloride solution while stirring via a magnetic stir bar. Place Flask 1 in a freezer at -20 &#176;C overnight for storage.</li>
	<li>Remove Flask 1 from the freezer and allow to warm to room temperature. Pour the solution from Flask 1 into a 500 mL separatory funnel.</li>
	<li>Add 50 mL dichloromethane (DCM), cap the separatory funnel, and rock gently to mix the DCM and aqueous/THF mixture to extract the product into the organic layer. Collect the organic layer into a 500 mL beaker containing an appropriately sized magnetic stir bar by opening the separatory funnel stopcock and set aside. Repeat two times.</li>
	<li>Collect all the organics into the same beaker and stir over magnesium sulfate (to remove any residual water) using a magnetic stir plate until the magnesium sulfate no longer clumps when added to solution. Discard the aqueous waste.</li>
	<li>Remove the magnesium sulfate solid from the organic product solution by using a filter paper inside a glass funnel and collect the organics in a 250 mL round bottom flask. Rinse the filter paper and solid magnesium sulfate with excess DCM to ensure that all the product is collected.</li>
	<li>Remove the solvent from the product by rotary evaporation while heating at 30 &#176;C and using a water aspirator as the vacuum source.</li>
	<li>Purify the crude product by column chromatography10 using a silica gel as the stationary phase and eluting beginning with 3% ethyl acetate/hexanes for 1 column volume (CV), increasing the gradient to 29% ethyl acetate/hexanes over 5 CVs. Collect the fractions in 16 x 150 mm2 borosilicate glass tubes.</li>
	<li>Perform thin layer chromatography using 20% ethyl acetate/hexanes as eluent to determine the product fractions.</li>
	<li>Combine all product fractions into an appropriately sized round bottom flask and remove the solvent using rotary evaporation at 40 &#176;C. Transfer to a pre-weighed product vial and place under a high vacuum at 0.05 torr to obtain pure AVL. Characterize the product by 1H NMR11 (CDCl3, 400 MHz): &#948; 5.75 (m, 1H), 5.06 (m, 2H), 4.26 (m, 2H), 2.54 (m, 3H), 2.28 (m, 1H), 2.03 (m, 1H), 1.87 (m, 1H), 1.54 (m, 1H). Yield: 2.07 g (70.56%).</li>
</ol>
2. Synthesis and Characterization of VL- co- AVL
<ol>
	<li>Flame dry and purge with nitrogen gas a 25 mL round bottom flask equipped with a magnetic stir bar and septum.
	<ol>
		<li>Flame dry the flask to remove moisture by purging with nitrogen gas connected through an inlet needle and open outlet needle in the septum, while using a butane flame torch to gently heat the outside of the flask by moving the flame along the surface.</li>
		<li>Continue heating the entire flask by running the flame across the surface until moisture clouding the inside of the flask is not seen. Remove the flame and let the flask cool to room temperature while continuing the nitrogen flow throughout the reaction.</li>
	</ol>
	</li>
	<li>Quickly remove the septum from the round bottom and add tin(II) triflate (2.5 mg, 5.9&#160; x 10-6 mol) to the very bottom of the flask using a spatula. Replace the septum.</li>
	<li>Add 3-methyl-1-butanol (72.6 &#181;L, 6.6 x 10-3 mol) via a 100 &#181;L microsyringe and 1.33 mL anhydrous DCM via a 2 mL syringe sequentially. Stir via a magnetic stir plate for 10 min.</li>
	<li>Add AVL (0.48 mL, 3.7 x 10-3 mol) and VL (1.37 mL, 1.4 x 10-2 mol) sequentially via a syringe. Allow to continue stirring for 18 - 20 h. 
	NOTE: The AVL and VL percentage in the final copolymer can be altered by stoichiometry in this step.</li>
	<li>Quench the reaction by adding ~5 mL methanol (MeOH). Add ~100 mg solid-support tin scavenger and stir for 2 h. Filter by gravity filtration to remove the solid.</li>
	<li>Remove the solvent under rotary evaporation with a water aspirator as the vacuum source while heating at 30 &#176;C until the solution is viscous. Precipitate the solution dropwise into 500 mL cold MeOH (chilled with dry ice for at least 1 h) to produce flakes of white solid. Filter the solution by vacuum filtration into a funnel containing a fritted glass disc with filter paper to collect the solid. 
	NOTE: If precipitation produces a cloudy supernatant or fine powder which goes through the filter paper, then the product solution is too dilute. All supernatant solvent should be removed by rotary evaporation with a water aspirator as the vacuum source while heating at 30 &#176;C until the solution is viscous and then precipitation should be performed again.</li>
	<li>Transfer the solid product to a pre-weighed vial via a spatula and dry overnight via high vacuum pressure of 0.05 torr to collect the white, flaky solid.</li>
	<li>Characterize the polymer by 1H NMR11 (CDCl3, 400 MHz): &#948; 5.71 (m, 1H), 5.03 (t, 2H), 4.08 (m, 4H), 3.65 (t, 2H), 2.15 - 2.50 (m, 5H), 1.47-1.78 (m, 9H), 0.91 (d, 6H). 81.42% VL, 18.58% AVL, 2,940 g/mol, 578 g/mol repeat unit of AVL. Yield: 1.43 g, (73.43%).</li>
</ol>
3. Post-polymerization Epoxidation to Produce Epoxy-valerolactone (EVL) Copolymer Units
<ol>
	<li>Add VL-co-AVL copolymer (500 mg, 1.7&#160; x 10-4 mol, 2,940 g/mol) to a 6-dram vial with a magnetic stir bar. Add 6.15 mL anhydrous DCM to the vial and vortex to solubilize the polymer.</li>
	<li>Add meta-chloroperoxybenzoic acid (mCPBA) (74.53 mg, 4.3 x 10-4 mol) to a second 6-dram vial. Add 6.15 mL anhydrous DCM and vortex until the mCPBA is solubilized completely. 
	NOTE: The conversion ratio of allyls to epoxides can be varied by altering the stoichiometry in this step. The final allyl concentration in the solvent should be 0.065 M.</li>
	<li>Transfer the mCPBA solution to the VL-AVL solution. Cap the reaction and cover with a plastic paraffin film. Allow to stir for 48 h.</li>
	<li>Transfer the reaction mixture to a 50 mL separatory funnel. Add 15 mL saturated sodium bicarbonate, cap the separatory funnel, and rock gently to mix. Collect the organic layer containing the product into a 50 mL Erlenmeyer flask with an appropriate sized magnetic stir bar (product flask).
	<ol>
		<li>Add 5 mL DCM to the aqueous layer that is still in the separatory funnel, cap, and then rock gently. Collect the organics into the product flask. Discard the aqueous waste. Transfer the organic layer back into a separatory funnel. Repeat this aqueous wash two times.</li>
	</ol>
	</li>
	<li>Add magnesium sulfate (to remove any residual water) to the product flask while stirring over a magnetic stir plate. Continue adding small scoops of magnesium sulfate until it no longer clumps when added. Use a glass funnel fitted with a filter paper to remove the solid magnesium sulfate while transferring the mixture to a 50 mL round bottom flask.</li>
	<li>Remove the solvent by rotary evaporation with a water aspirator as the vacuum source and heating at 25 &#176;C. Transfer the contents of the round bottom flask to a pre-weighed product vial and remove the solvent by rotary evaporation. Place on high vacuum at 0.05 torr overnight to produce a white, waxy solid.</li>
	<li>Characterize by 1H NMR11 (CDCl3, 400 MHz): &#948; 5.71 (m, 1H), 5.03 (t, 2H), 4.08 (m, 4H), 3.65 (t, 2H), 2.94 (d, 1H), 2.90 (s, 1H), 2.74 (s, 1H), 2.15-2.50 (m, 5H), 1.47-1.78 (m, 9H), 0.92 (d, 6H). 84.53% VL, 9.65% AVL, 5.82% EVL, 2,855 g/mol, 1,841 g/mol repeat unit of EVL. Yield: 417.3 mg, (83.46%).</li>
</ol>
4. Nanosponge Synthesis and Characterization
<ol>
	<li>Dissolve the VL-co-AVL-co-EVL polymer (200 mg, 7.0 x 10-5 mol, 2,855 g/mol) in 20.01 mL anhydrous DCM for an epoxide concentration of 0.0054 M. Transfer to a 100 mL round bottom flask with a 14/20 neck. 
	NOTE: To catalyze the reaction, 100 &#181;L aqueous saturated sodium bicarbonate can be added in this step.</li>
	<li>Place the reaction flask in an oil bath at 50 &#176;C. Stir the solution with a fast vortex and add 2,2&#39;-(ethylenedioxy)bis(ethylamine) (21.45 &#181;L, 2.9 10-4 mol) via a microsyringe dropwise. Fit the neck of the flask with a water-jacketed condenser with cool water flowing through it, fitted with a 14/20 neck adapter, and reflux the solution for 12 h. Ensure a very tight seal between the neck of the flask and the condenser to avoid solvent evaporation.</li>
	<li>Remove excess solvent from the reaction flask by rotary evaporation at 25 &#176;C until a viscous solution is obtained.</li>
	<li>Place a large magnetic stir bar into a 2 L beaker. Cut an approximately six-inch section of 10 K molecular weight cut-off (MWCO) dialysis tubing and fold one end then close with a dialysis clip.
	<ol>
		<li>Transfer the product to 10 K MWCO dialysis tubing. Rinse the flask with excess DCM and transfer it to the tubing.Fold the top of the tubing and close with a dialysis clip that has a wire for hanging. Hang the dialysis tubing on the side of the beaker using the wire and fill the beaker with DCM until the dialysis tubing is completely submerged.</li>
		<li>Place on a magnetic stir plate and stir gently. Cover the beaker with aluminum foil to prevent solvent evaporation. Remove the solvent by pouring into a waste container and replace with fresh DCM three times daily for 48 h to remove the unreacted polymer and crosslinker.</li>
	</ol>
	</li>
	<li>Remove all solvent from the beaker and transfer the contents of the dialysis tubing to a 10 mL syringe fitted with a 0.45 &#181;m polytetrafluoroethylene (PTFE) syringe filter. Push the solution through the filter directly into a pre-weighed product vial to remove any remaining impurities. Remove the solvent by rotary evaporation at 25 &#176;C, then place on high vacuum at 0.05 torr overnight to collect the light yellow, waxy solid.</li>
	<li>Characterize by 1H NMR11 (CDCl3, 400 MHz): &#948; 5.71 (m, 1H), 5.03 (t, 2H), 4.08 (m, 4H), 3.60-3.67 (t, 14H), 2.94 (d, 1H), 2.90 (s, 1H), 2.74 (s, 1H), 2.15-2.50 (m, 5H), 1.47-1.78 (m, 9H), 0.92 (d, 6H). Yield: 176.9 mg (88.45%).</li>
</ol>
5. TEM Imaging of Nanosponge Morphology and Size
<ol>
	<li>Filter 5 mL cell culture water through a 0.2 &#181;m PTFE syringe filter.</li>
	<li>Place 0.5 mg nanosponges into a 1.5 mL centrifuge tube. Add 1 mL filtered cell culture water. Use a probe sonicator (20 kHz, 40 a) to sonicate the solution with 2 s bursts 4 - 5 times at room temperature until the particles have developed a fine suspension. Do not use prolonged sonication or let the solution heat up as this will cause aggregation.</li>
	<li>Add 30 mg phosphotungstic acid hydrate (PTA) to 1 mL filtered cell culture water in a 1.5 mL centrifuge tube. Vortex on the highest setting for 10 s or until the PTA is completely solubilized to produce 3% PTA solution.</li>
	<li>Use a 1 mL syringe with 22 G needle to draw up 0.5 mL 3% PTA solution. Add 4 drops of the 3% PTA solution to the particles and vortex on the highest setting for 10 s. Use a pair of self-closing tweezers to pick up a TEM grid then dip it into the particles solution quickly, three times. Let the grid dry for 5 h under a cover to reduce dust collection on the grid.</li>
	<li>Perform TEM imaging12 of the sample using high contrast and 40 &#181;m objective.</li>
</ol>

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저자는 공개 없다.

재현할 수 nanosponge 크기를 얻는 것은 약물 전달 응용 프로그램에 매우 중요입니다. 여러 매개 변수 중 합 및 nanosponge 합성 결과 입자의 크기와 crosslink 밀도를 영향을 줍니다. 세 가지 중요 한 매개 변수 분석에서 확인 되었다: 분자량 폴리머, 에폭시 펜 던 트 기능, 및 crosslinker에 해당. 다양 한 분자 무게와 nanosponge 합성에 대 한 에폭시 기능을 일으키기 위하여는 VL-co-AVL 공중 합체의 산출할 변...

Intermolecular 가교에 따라 나노 입자의 크기와 가교 밀도 정확 하 게 튜닝 영향 및 이러한 nanosystems1의 약물 방출 프로 파일을 안내에 매우 중요입니다. 디자인 nanosponge tunability, 즉, 다른 네트워크 밀도의 입자를 준비 하 고, 전조 폴리머의 펜 던 트 기능 및 통합 친수성 crosslinker의 등가물에 의존. 이 방법에서는, 선구자 및 용 매에 crosslinker의 농도 대량 젤 보다는 개별 크기의 나노 입자 형성에 중요 하다. 특성화 기법으로 양적 핵 자기 공명 분광학 (NMR)을 이용 하 여 법인된 펜 던 트 기능 및 고분자 분자량의 정확한 결정 수 있습니다. 나노 입자 형성 된다, 일단 그들은 집중 고는 nanogel의 문자 하지 않고 생명체에서 solubilized.
나노 약물 전달에서 최근 작품 폴 리의 사용에 집중 했다 (유산-co-글리콜 산) (PLGA) 자기 조립 나노2,,34,,56. PLGA 분해 에스테 르 결합 약물 전달 응용 프로그램에 적합 하 게 있으며 종종 그 스텔스 속성7인 poly(ethylene glycol) (PEG)와 결합. 그러나, PLGA 입자 형성의 자기 조립 특성, 입자는 더 기능화에 대 한 생명체에서 solubilized 수 없습니다. PLGA 나노 입자, 달리 제안된 된 방법 정의 된 크기와 형태, 생명체에 안정 하 고 저하 수성 솔루션1나노 입자를 형성 하는 화학식 가교를 제공 합니다. 이 방법의 장점은 추가 화학적 functionalize nanosponge8의 표면 수 그리고 유기 용 매에 있는 그것의 안정성 제약 화합물1,9입자의 포스트 로드에 사용할 수 있습니다. 이 방법으로 수성 매체에 강 수에 의해 소수 작은 분자의 캡슐화를 구현할 수 있습니다. 친수성 짧은 crosslinker 함께 폴 리 에스테 등뼈의 hydrophobicity는 체온에 비정 질 문자가이 입자를 제공합니다. 또한, 마약 로드, 후 입자 형성할 수 있다 좋은 정지 쉽게 주입된 비보수 수성 매체에서. 이러한 폴 리 에스테 르 nanosponges의 합성에 대 한 매개 변수를 평가 하 고 그 극히 중요 한 설계 및 제어의 크기와 형태를 결정 하는이 작품에서 우리의 목표 이다.

<table><tbody><tr><td>2,2&#039;-(Ethylenedioxy)bis(ethylamine)</td><td>Sigma-Aldrich</td><td>385506-100ML</td><td></td></tr><tr><td>3-methyl-1-butanol</td><td>Sigma-Aldrich</td><td>309435-100ML</td><td>anhydrous, &amp;ge;99%</td></tr><tr><td>Acetone</td><td>Sigma-Aldrich</td><td>179124-4L</td><td></td></tr><tr><td>Allyl bromide</td><td>Sigma-Aldrich</td><td>A29585-5G</td><td>&amp;ge;99%</td></tr><tr><td>Ammonium chloride</td><td>Fisher Scientific</td><td>A661-500</td><td>saturated solution in DI water</td></tr><tr><td>Cell culture water</td><td>Sigma-Aldrich</td><td>W3500-500ML</td><td>Filtered through 0.45 &amp;mu;m syringe filter</td></tr><tr><td>Dichloromethane (DCM)</td><td>Sigma-Aldrich</td><td>270997-100ML</td><td>anhydrous, &amp;ge;99%, contains 40 - 150 ppm amylene as stabilizer</td></tr><tr><td>Ethyl Acetate</td><td>Fisher Scientific</td><td>E145SK-4</td><td></td></tr><tr><td>EZFlow 0.2 &amp;mu;m Syringe Filter</td><td>Foxx Life Sciences</td><td>386-2116-OEM</td><td>Hydrophillic PTFE, 13 mm</td></tr><tr><td>EZFlow 0.45 &amp;mu;m Syringe Filter</td><td>Foxx Life Sciences</td><td>386-3126-OEM</td><td>Hydrophillic PTFE, 25 mm</td></tr><tr><td>Fisherbrand Disposable Borosilicate Glass Test Tubes with Plain End</td><td>Fisher Scientific</td><td>14-961-31</td><td></td></tr><tr><td>Fisherbrand Microcentrifuge Tubes</td><td>Fisher Scientific</td><td>14-666-318</td><td>1.5 mL</td></tr><tr><td>Hamilton Microliter Syringe, 100 &amp;mu;L</td><td>Hamilton Company</td><td>80600</td><td>Model 710 N SYR, Cemented NDL, 22s ga, 2 in, point style 2</td></tr><tr><td>Hexamethylphosphoramide</td><td>Sigma-Aldrich</td><td>H11602-100G</td><td>&amp;ge;99%, contains &amp;le;1,000 ppm propylene oxide as stabilizer</td></tr><tr><td>Hexanes</td><td>Fisher Scientific</td><td>H292-4</td><td></td></tr><tr><td>Magnesium sulfate anhydrous</td><td>Fisher Scientific</td><td>M65-500</td><td></td></tr><tr><td>Meta-chloroperoxybenzoic acid</td><td>Sigma-Aldrich</td><td>273031-100G</td><td>Purified to &amp;ge;99% by buffer wash</td></tr><tr><td>Methanol (MeOH)</td><td>Sigma-Aldrich</td><td>322415-100ML</td><td>anhydrous, &amp;ge;99%</td></tr><tr><td>N-butyllithium solution</td><td>Sigma-Aldrich</td><td>230707-100ML</td><td>2.5 M in hexanes</td></tr><tr><td>N,N-diisopropylethylamine</td><td>Sigma-Aldrich</td><td>550043-500ML</td><td>&amp;ge;99%</td></tr><tr><td>Parafilm M</td><td>Sigma-Aldrich</td><td>P7793-1EA</td><td></td></tr><tr><td>PELCO Pro Reverse (Self-Closing) Tweezers</td><td>Ted Pella, Inc.</td><td>5375-NM</td><td></td></tr><tr><td>Phosphotungstic acid hydrate</td><td>Alfa Aesar</td><td>40116</td><td></td></tr><tr><td>Q55 Sonicator</td><td>Qsonica</td><td>Q55-110</td><td>55 Watts, 20 kHz</td></tr><tr><td>SiliaMetS Cysteine</td><td>Silicycle</td><td>R80530B-10g</td><td></td></tr><tr><td>SnakeSkin Dialysis Clips</td><td>Thermo Scientific</td><td>68011</td><td></td></tr><tr><td>SnakeSkin Dialysis Tubing, 10K MWCO</td><td>Thermo Scientific</td><td>68100</td><td></td></tr><tr><td>Sodium bicarbonate</td><td>Fisher Scientific</td><td>5233-500</td><td>saturated solution in DI water</td></tr><tr><td>TEM grid</td><td>Ted Pella, Inc.</td><td>01822-F</td><td>Ultrathin Carbon Type-A, 400 mesh, Copper, approx. grid hole size: 42 &amp;micro;m</td></tr><tr><td>Tetrahydrofuran (THF)</td><td>Sigma-Aldrich</td><td>401757-1L</td><td>Anhydrous, &amp;ge;99.9%, inhibitor-free</td></tr><tr><td>Tin(II) trifluoromethanesulfonate</td><td>Sigma-Aldrich</td><td>388122-1G</td><td></td></tr><tr><td>Vortex-Genie 2</td><td>Scientific Industries</td><td>SI-0236</td><td></td></tr><tr><td>Whatman Filter Paper, Grade 1</td><td>Fisher Scientific</td><td>09-805H</td><td>Circles, 185 mm</td></tr><tr><td>&amp;delta;-valerolactone</td><td>Sigma-Aldrich</td><td>389579-100ML</td><td>Purified by vacuum distillation</td></tr></tbody></table>

nanosponge tunability in size and crosslinking density

우리는 펜 던 트 에폭시 기능 및 제어 치수와 nanosponge에 그들의 설립을 포함 하는 선형 폴 리 에스테의 합성에 대 한 프로토콜을 설명 합니다. 이 방법은 결과 폴리머의 펜 던 트 기능화에 열쇠는 기능성된 lactone의 합성으로 시작 됩니다. Valerolactone (VL) 및 알릴-valerolactone (AVL)는 반지 개통 중 합을 사용 하 여 다음 copolymerized 있습니다. 후 중 합 수정 다음 펜 던 트 알릴 그룹의 일부 또는 전부에 에폭시 moiety를 설치 하는 데 사용 됩니다. 에폭시-아민 화학 형태 나노 입자를 고분자의 분자 diamine crosslinker 원하는 nanosponge 크기와 가교 밀도에 따라 묽 게 한 해결책에서 채택 된다. Nanosponge 크기는 전송 전자 현미경 (TEM) 이미징 차원 및 배포 결정에 의해 특징 수 있습니다. 이 메서드는 높게 가변 폴리에스터 가변 나노 입자, 작은 분자 약물 캡슐화에 사용 될 수 있는 만들 수 있는 통로 제공 합니다. 등뼈의 특성상,이 입자는 소수 작은 분자의 광범위의 제어 릴리스에 대 한 가수분해로 및 효소 분해.

결과 크기는 nanosponge의 합성 매개 변수 사이의 관계를 평가 하려면 각 중합체 선구자의 농도 및 펜 던 트 기능 중요 하다. 그림 1, nanosponges의 successfulsynthetic 계획 두 선구자 폴리머와 diamine crosslinker DCM에 12 h에 대 한 통합 후 환류 조건 하에서 밖으로 수행 됩니다. 솔루션에서 epoxides의 농도 또한 개별 입자 형성에 긴요 하다. Nanosponges 합성 했다, 일단 ?...

Watch this Scientific Journal Video about Nanosponge Tunability in Size and Crosslinking Density at JoVE.com

Nanosponge Tunability in Size and Crosslinking Density

이 문서는 펜 던 트 기능을 포함 하는 선형 폴 리 에스테에서 covalently 가교 된 나노 입자의 크기와 가교 밀도 조정 프로세스를 설명 합니다. 합성 매개 변수 (고분자 분자량, 펜 던 트 기능 통합, 및 crosslinker에 해당)을 조정 하면, 약물 전달 응용 프로그램에 대 한 원하는 나노 크기와 가교 밀도 얻을 수 있습니다.

Nanosponge Tunability 크기와 가교 밀도

We describe a protocol for the synthesis of linear polyesters containing pendant epoxide functionality and their incorporation into a nanosponge with ...

nanosponge-tunability-in-size-and-crosslinking-density

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Ethers, Epoxides, Sulfides

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7.5K 조회수.  Vanderbilt University. 이 문서는 펜 던 트 기능을 포함 하는 선형 폴 리 에스테에서 covalently 가교 된 나노 입자의 크기와 가교 밀도 조정 프로세스를 설명 합니다. 합성 매개 변수 (고분자 분자량, 펜 던 트 기능 통합, 및 crosslinker에 해당)을 조정 하면, 약물 전달 응용 프로그램에 대 한 원하는 나노 크기와 가교 밀도 얻을 수 있습니다.

비디오: Nanosponge Tunability in Size and Crosslinking Density

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

3D 카본 나노튜브 Microstructures의 제조, Densification 및 복제 성형

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

연구

공학

Dispersion of Nanomaterials in Aqueous Media: Towards Protocol Optimization

The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and stability of the suspension. In this study, a systematic step-wise approach is carried out to identify optimal sonication conditions in order to achieve a stable dispersion. This approach has been adopted and shown to be suitable for several nanomaterials (cerium oxide, zinc oxide, and carbon nanotubes) dispersed in deionized (DI) water. However, with any change in either the nanomaterial type or dispersing medium, there needs to be optimization of the basic protocol by adjusting various factors such as sonication time, power, and sonicator type as well as temperature rise during the process. The approach records the dispersion process in detail. This is necessary to identify the time points as well as other above-mentioned conditions during the sonication process in which there may be undesirable changes, such as damage to the particle surface thus affecting surface properties. Our goal is to offer a harmonized approach that can control the quality of the final, produced dispersion. Such a guideline is instrumental in ensuring dispersion quality repeatability in the nanoscience community, particularly in the field of nanotoxicology.

Here, we present a step-wise protocol for the dispersion of nanomaterials in aqueous media with real-time characterization to identify the optimal sonication conditions, intensity, and duration for improved stability and uniformity of nanoparticle dispersions without impacting the sample integrity.

수성 미디어에 나노 재료의 분산: 프로토콜 최적화 쪽으로

The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and ...

환경과학

Functionalization of Single-walled Carbon Nanotubes with Thermo-reversible Block Copolymers and Characterization by Small-angle Neutron Scattering

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous solution. In a carbon nanotube/PEO105-PPO70-PEO105 (poloxamer 407) aqueous solution, the amphiphilic poloxamer 407 adsorbs onto the carbon nanotube surfaces and self-assembles into continuous layers, driven by intermolecular interactions between constituent molecules. The addition of 5-methylsalicylic acid changes the self-assembled structure from spherical-micellar to a cylindrical morphology. The fabricated poloxamer 407/carbon nanotube hybrid particles exhibit thermo-responsive structural features so that the density and thickness of poloxamer 407 layers are also reversibly controllable by varying temperature. The detailed structural properties of the poloxamer 407/carbon nanotube particles in suspension can be characterized by small-angle neutron scattering experiments and model fit analyses. The distinct curve shapes of the scattering intensities depending on temperature control or addition of aromatic additives are well described by a modified core-shell cylinder model consisting of a carbon nanotube core cylinder, a hydrophobic shell, and a hydrated polymer layer. This method can provide a simple but efficient way for the fabrication and in-situ characterization of carbon nanotube-based nano particles with a structure-tunable encapsulation.

A method for the functionalization of carbon nanotubes with structure-tunable polymeric encapsulation layers and structural characterization using small-angle neutron scattering is presented.

작은 각도 중성자 산란에 의한 열 가역적 블록 공중 합체 및 특성 단일 벽 탄소 나노 튜브의 기능화

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous ...

화학

Grafting Multiwalled Carbon Nanotubes with Polystyrene to Enable Self-Assembly and Anisotropic Patchiness

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a free-radical polymerization strategy to enable the modulation of the nanotube surface properties and produce supramolecular self-assembly of the nanostructures. First, a selective hydroxylation of the pristine nanotubes through a biphasic catalytically mediated oxidation reaction creates superficially distributed reactive sites at the sidewalls. The latter reactive sites are subsequently modified with methacrylic moieties using a silylated methacrylic precursor to create polymerizable sites. Those polymerizable groups can address further polymerization of styrene to produce a hybrid nanomaterial containing PS chains grafted to the nanotube sidewalls. The polymer-graft content, amount of silylated methacrylic moieties introduced and hydroxylation modification of the nanotubes are identified and quantified by Thermogravimetric Analysis (TGA). The presence of reactive functional groups hydroxyl and silylated methacrylate are confirmed by Fourier Transform Infrared Spectroscopy (FT-IR). Polystyrene-grafted carbon nanotube solutions in tetrahydrofuran (THF) provide wall-to-wall collinearly self-assembled nanotubes when cast samples are analyzed by transmission electron microscopy (TEM). Those self-assemblies are not obtained when suitable blanks are similarly cast from analogous solutions containing non-grafted counterparts. Therefore, this method enables the modification of the nanotube anisotropic patchiness at the sidewalls which results into spontaneous auto-organization at the nanoscale.

A procedure for the synthesis of polystyrene-grafted multiwalled carbon nanotubes using successive chemical modification steps to selectively introduce the polymer chains to the sidewalls and their self-assembly via anisotropic patchiness is presented.

자기 집합에 있도록 폴리스 티 렌과 이방성 Patchiness Multiwalled 탄소 나노튜브를 접목

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a ...

Multiscale Structures Aggregated by Imprinted Nanofibers for Functional Surfaces

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing challenge in the field is the fabrication of hybrid micro-nano structures using a facile, cost-effective, and high-throughput method. To overcome these challenges, this paper proposes a protocol to fabricate multiscale structures using only an imprint process with an anodic aluminum oxide (AAO) filter and an evaporative self-aggregation process of nanofibers. Unlike previous attempts that have aimed to straighten nanofibers, we demonstrate a unique fabrication method for multiscale aggregated nanofibers with high aspect ratios. Furthermore, the surface morphology and wettability of these structures on various liquids were investigated to facilitate their use in multifunctional surfaces.

Presented is an easy method to fabricate nano-micro multiscale structures, for functional surfaces, by aggregating nanofibers fabricated using an anodic aluminum oxide filter.

기능성 표면에 찍힌된 Nanofibers 여 집계 multiscale 구조

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing ...

Fabricating Degradable Thermoresponsive Hydrogels on Multiple Length Scales via Reactive Extrusion, Microfluidics, Self-assembly, and Electrospinning

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), their ultimate clinical use has been hampered by the lack of biologically-relevant degradation observed for most smart materials. This is particularly true for temperature-responsive hydrogels, which are almost uniformly based on polymers that are functionally non-degradable (e.g., poly(N-isopropylacrylamide) (PNIPAM) or poly(oligoethylene glycol methacrylate) (POEGMA)). As such, to effectively translate the potential of thermoresponsive hydrogels to the challenges of remote-controlled or metabolism-regulated drug delivery, cell scaffolds with tunable cell-material interactions, theranostic materials with the potential for both imaging and drug delivery, and other such applications, a method is required to render the hydrogels (if not fully degradable) at least capable of renal clearance following the required lifetime of the material. To that end, this protocol describes the preparation of hydrolytically-degradable hydrazone-crosslinked hydrogels on multiple length scales based on the reaction between hydrazide and aldehyde-functionalized PNIPAM or POEGMA oligomers with molecular weights below the renal filtration limit. Specifically, methods to fabricate degradable thermoresponsive bulk hydrogels (using a double barrel syringe technique), hydrogel particles (on both the microscale through the use of a microfluidics platform facilitating simultaneous mixing and emulsification of the precursor polymers and the nanoscale through the use of a thermally-driven self-assembly and cross-linking method), and hydrogel nanofibers (using a reactive electrospinning strategy) are described. In each case, hydrogels with temperature-responsive properties similar to those achieved via conventional free radical cross-linking processes can be achieved, but the hydrazone cross-linked network can be degraded over time to re-form the oligomeric precursor polymers and enable clearance. As such, we anticipate these methods (which may be generically applied to any synthetic water-soluble polymer, not just smart materials) will enable easier translation of synthetic smart materials to clinical applications.

Protocols are described for the fabrication of degradable thermoresponsive hydrogels based on hydrazone cross-linking of polymeric oligomers on the bulk scale, microscale, and nanoscale, the latter for preparation of both gel nanoparticles and nanofibers.

자기 조립, 분해 Thermoresponsive Hydrogels 반응 압출, 마이크로, 통해 여러 길이 가늠 자에를 조작 하 고 전기

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), ...

생체공학

DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of flexible polymers nor of rigid rods. Underlying filaments remain outstretched due to their non-vanishing backbone stiffness, which is quantified via the persistence length (lp), but they are also subject to strong thermal fluctuations. Their finite bending stiffness leads to unique, non-trivial collective mechanics of bulk networks, enabling the formation of stable scaffolds at low volume fractions while providing large mesh sizes. This underlying principle is prevalent in nature (e.g., in cells or tissues), minimizing the high molecular content and thereby facilitating diffusive or active transport. Due to their biological implications and potential technological applications in biocompatible hydrogels, semiflexible polymers have been subject to considerable study. However, comprehensible investigations remained challenging since they relied on natural polymers, such as actin filaments, which are not freely tunable. Despite these limitations and due to the lack of synthetic, mechanically tunable, and semiflexible polymers, actin filaments were established as the common model system. A major limitation is that the central quantity lp cannot be freely tuned to study its impact on macroscopic bulk structures. This limitation was resolved by employing structurally programmable DNA nanotubes, enabling controlled alteration of the filament stiffness. They are formed through tile-based designs, where a discrete set of partially complementary strands hybridize in a ring structure with a discrete circumference. These rings feature sticky ends, enabling the effective polymerization into filaments several microns in length, and display similar polymerization kinetics as natural biopolymers. Due to their programmable mechanics, these tubes are versatile, novel tools to study the impact of lp on the single-molecule as well as the bulk scale. In contrast to actin filaments, they remain stable over weeks, without notable degeneration, and their handling is comparably straightforward.

Semiflexible polymers display unique mechanical properties that are extensively applied by living systems. However, systematic studies on biopolymers are limited since properties such as polymer rigidity are inaccessible. This manuscript describes how this limitation is circumvented by programmable DNA nanotubes, enabling experimental studies on the impact of filament rigidity.

Semiflexible 고분자 공부를 다양 한 도구로 DNA 나노튜브

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of ...

Microhoneycomb Monoliths Prepared by the Unidirectional Freeze-drying of Cellulose Nanofiber Based Sols: Method and Extensions

Monolithic honeycomb structures have been attractive to multidisciplinary fields due to their high strength-to-weight ratio. Particularly, microhoneycomb monoliths (MHMs) with micrometer-scale channels are expected as efficient platforms for reactions and separations because of their large surface areas. Up to now, MHMs have been prepared by a unidirectional freeze-drying (UDF) method only from very limited precursors. Herein, we report a protocol from which a series of MHMs consisting of different components can be obtained. Recently, we found that cellulose nanofibers function as a distinct structure-directing agent towards the formation of MHMs through the UDF process. By mixing the cellulose nanofibers with water soluble substances which do not yield MHMs, a variety of composite MHMs can be prepared. This significantly enriches the chemical constitution of MHMs towards versatile applications.

Here, we present a general protocol to prepare a variety of microhoneycomb monoliths (MHMs) in which fluid can pass through with an extremely low pressure drop. MHMs obtained are expected to be used as filters, catalyst supports, flow-type electrodes, sensors and scaffolds for biomaterials.

셀 루 로스 Nanofiber 단방향 동결에 의해 준비 Microhoneycomb Monoliths 기반 Sols: 메서드 및 확장

Monolithic honeycomb structures have been attractive to multidisciplinary fields due to their high strength-to-weight ratio. Particularly, microhoneycomb ...

Synthesis of Stimuli-responsive Nanogels using Aqueous One-step Crosslinking and Co-nanopolymerization

Nanogels consisting of crosslinked-polymeric nanoparticles have been developed for the delivery of numerous chemical and biological therapeutics, owing to their versatile bottom-up synthesis and biocompatibility. While various methods have been employed for nanogel synthesis to date, very few have achieved it without the use of harsh organic solvents or high temperatures that can damage the integrity of the biological payload. In contrast, the methodology presented here accomplishes the synthesis of sub-100 nm sized, protein-loaded nanogels using mild reaction conditions. Here, we present a method for the non-covalent encapsulation of protein-based payloads within nano-gels that were synthesized using an aqueous-based, single-step, crosslinking copolymerization technique. In this technique, we initially electrostatically bind a protein-based payload to a cationic quaternary ammonium monomer and simultaneously cross-link and co-polymerize it using ammonium persulfate and N,N,N&#39;,N&#39;-tetramethylethylenediamine to form nanogels that entrap the protein payload. The size and polydispersity index of the nanogels is determined using dynamic light scattering (DLS), while the surface morphology is assessed by transmission electron microscopy (TEM). The mass of protein entrapped within nanogels is determined by calculating the encapsulation efficiency. Furthermore, the controlled-release ability of the nanogels via the gradual degradation of redox-responsive structural elements is also assessed in bioreduction assays. We provide examples of nanoparticle optimization data to demonstrate all caveats of nanogel synthesis and characterization using this technique. In general, uniformly sized nanogels were obtained with an average size of 57 nm and a polydispersity index value of 0.093. A high encapsulation efficiency of 76% was achieved. Furthermore, the nanogels exhibited controlled release of up to 86% of the encapsulated protein by gradual degradation of novel redox-responsive components in the presence of glutathione over 48 h.

Nanogels are an excellent and versatile nanoparticle platform for the delivery of biologics. Stimuli-responsive poly(ethylene) glycol-based polymeric nano-gels, capable of encapsulating protein-based payloads, were synthesized using a one-step cross-linking co-nanopolymerization strategy in aqueous conditions. The optimal fabrication and characterization of these novel nanoparticles are presented here.

Aqueous One-step Crosslinking 및 Co-nanopolymerization을 이용한 Stimuli-responsive Nanogel 합성

Nanogels consisting of crosslinked-polymeric nanoparticles have been developed for the delivery of numerous chemical and biological therapeutics, owing to ...

Procedure for Fabricating Biofunctional Nanofibers

Electrospinning is an effective processing method for preparing nanofibers decorated with functional groups. Nanofibers decorated with functional groups may be utilized to study material-biomarker interactions i.e. act as biosensors with potential as single molecule detectors. We have developed an effective approach for preparing functional polymers where the functionality has the capacity of specifically binding with a model protein. In our model system, the functional group is 2,4-dinitrophenyl (DNP) and the protein is anti-DNP IgE (Immunoglobulin E). The functional polymer, &alpha;,&omega;-bi[2,4-dinitrophenyl caproic][poly(ethylene oxide)-b-poly(2-methoxystyrene)-b-poly(ethylene oxide)] (CDNP-PEO-P2MS-PEO-CDNP), is prepared by anionic living polymerization. The difunctional initiator utilized in the polymerization was prepared by electron transfer reaction of &alpha;-methylstyrene and potassium (mirror) metal. The 2-methoxystyrene monomer was added first to the initiator, followed by the addition of the second monomer, ethylene oxide, and finally the living polymer was terminated by methanol. The &alpha;,&omega;-dihydroxyl polymer [HO-PEO-P2MS-PEO-OH] was reacted with N-2,4-DNP-&isin;-amino caproic acid, by DCC coupling, resulting in the formation of &alpha;,&omega;-bi[2,4-dinitrophenylcaproic][poly(ethyleneoxide)-b-poly(2-methoxystyrene)-b-poly(ethylene oxide)] (CDNP-PEO-P2MS-PEO-CDNP). The polymers were characterized by FT-IR, 1H NMR and Gel Permeation Chromatography (GPC). The molecular weight distributions of the polymers were narrow (1.1-1.2) and polymers with molecular weights greater than 50,000 was used in this study. The polymers were yellow powders and soluble in tetrahydrofuran. A water soluble CDNP-PEO-P2MS-PEO-CDNP/ DMEG (dimethoxyethylene glycol) complex binds and achieves steady state binding with solution IgE within a few seconds. Higher molecular weight (water insoluble i.e. around 50,000) CDNP-PEO-P2MS-PEO-CDNP polymers, containing 1% single wall carbon nanotubes (SWCNT) were processed into electroactive nanofibers (100 nm to 500 nm in diameter) on silicon substrate. Fluorescence spectroscopy shows that anti-DNP IgE interacts with the nanofibers by binding with the DNP functional groups decorating the fibers. These observations suggest that appropriately functionalized nanofibers hold promise for developing biomarker detection device.

An efficient approach for preparing nanofibers decorated with functional groups capable of specifically interacting with proteins is described. The approach first requires the preparation of a polymer functionalized with the appropriate functional group. The functional polymer is fabricated into nanofibers by electrospinning. The effectiveness of the binding of the nanofibers with a protein is studied by confocal microscopy.

Biofunctional Nanofibers를 제조 절차

Electrospinning is an effective processing method for preparing nanofibers decorated with functional groups. Nanofibers decorated with functional groups ...